bluuebunny/crossref_metadata_2025 huggingface dataset:
Biomechanical Comparisons of Anterior Cruciate Ligament Avulsion Fracture Fixation Using High-Strength Suture and Ultra-High Molecular Weight Polyethylene Suture Tape in a Porcine Model
Authors: Kubo Tatsuya , Takahashi Tsuneari , Kimura Masashi , Takeshita Katsushi
Published: January 2021

A wide variety of fixation methods have been reported to fix anterior cruciate ligament (ACL) tibial avulsion fractures, but there have been no studies into the fixation of these fractures with ultra-high molecular weight polyethylene (UHMWPE) suture tape as an alternative to conventional thread. Type III ACL tibial avulsion fractures were created in 20 skeletally immature porcine knees. All specimens were randomized into two treatment groups: (1) pullout repair using no. 2 suture fixation and (2) pullout repair using UHMWPE suture tape fixation. The specimens were tested cyclically (20 cycles, 0–40 N, 100 mm/min) in the direction of the native ACL and loaded to failure (100 mm/min) on a tensile tester. Statistically significant differences between the structural properties (displacement, upper yield load, maximum load, linear stiffness, and elongation at failure) under cyclic loading and single-cycle loading were analyzed. Displacement during cyclic testing was 1.56 ± 1.03 mm in the UltraBraid group and 0.99 ± 0.48 mm in the SUTURETAPE group, with no significant differences found between the groups (p = 0.13). There were no significant differences in upper yield load (161.9 ± 68.9 N in the UltraBraid group, 210.4 ± 60.1 N in the SUTURETAPE group, p = 0.11), linear stiffness (14.7 ± 4.7N/mm in the UltraBraid group, 18.1 ± 7.9 N/mm in the SUTURETAPE group, p = 0.27), or elongation at failure (20.1 ± 8.0 mm in the UltraBraid group, 21.5 ± 7.2 mm in the SUTURETAPE group, p = 0.69). On the other hand, significant differences were observed in maximum load in the SUTURETAPE group (219.7 ± 89.2 N in the UltraBraid group, 319.3 ± 92.6 N in the SUTURETAPE group, p = 0.025).
Short- to Midterm Outcomes of a Novel Guided-Motion Rotational Hinged Total Knee Arthroplasty
Authors: Yeroushalmi David , Laarhoven Simon Van , Tang Alex , Heesterbeek Petra J. C. , Hellemondt Gijs Van , Schwarzkopf Ran
Published: January 2021

Hinged prostheses have been increasingly utilized in complex and revision total knee arthroplasty (TKA) cases requiring additional mechanical support and global stability. However, there is limited data detailing the outcomes of modern hinge designs in these procedures. The aim of this study is to report a minimum 2-year functional outcomes and survivorship of a novel-guided motion-hinged knee TKA system. A multicenter, retrospective cohort study was conducted on consecutive TKA patients between March 2013 and August 2017 with a novel-guided motion-hinged knee system. Demographics, change in range of motion (ΔROM), quality metrics, and implant survivorship were collected with a minimum of 2-year follow-up. Implant survival was analyzed by using the Kaplan–Meier method. Overall, 147 hinged knee cases (18 complex primaries and 129 revisions) were identified with an average follow-up duration of 3.8 ± 1.2 years. Patients presented with an average of 2.4 ± 1.6 prior knee surgeries, and 51 (34.7%) had a history of knee infections. The ROM improved postoperatively: Δ extension = 2 ± 1 degrees, Δflexion = 7 ± 3 degrees, Δtotal ROM = 9 ± 4 degrees. Kaplan–Meier survivorship analysis for implant revision at 2- and 5-year follow-up showed a survival rate of 100 and 98.5% (95% confidence interval: 94.3–99.6%), respectively, with one patient undergoing two-stage revision for infection and another undergoing femoral revision for aseptic loosening. Survivorship for aseptic all-cause reoperation at 2- and 5-year follow-up was 93.2% (87.7–96.3%) and 88.2% (80.0–93.2%), respectively. Fourteen patients underwent aseptic reoperation (patellar complications: n = 7 [4.8%]; instability: n = 5 [3.4%]; tuberosity fixation: n = 1 [0.7%]; extensor mechanism failure: n = 1 [1.1%]). Survivorship for all-cause reoperation at 2- and 5-year follow-up were 85% (78.2–90.0%) and 77.7% (68.8–84.3%), respectively. Fifteen patients underwent reoperation for infection (DAIR: n = 14 (9.5%); two-stage revision: n = 1 [0.7%]). Despite some reoperations, this guided-motion hinged-knee TKA system demonstrates excellent survivorship for component revision compared to other modern hinged knee implants reported in the literature. Patients also displayed an improvement in knee ROM at their latest follow-up.
Dual Antibiotic Prophylaxis in Primary Total Knee Arthroplasty—No Benefit for Extremely Obese Patients
Authors: Lane Mark K. , Keeney James A.
Published: January 2021

We performed this study to assess the effectiveness of multimodal total knee arthroplasty prosthetic joint infection (TKA-PJI) prophylaxis including “on-time” dual-antibiotic prophylaxis, and the influence of body mass index (BMI) on prophylaxis effectiveness. After obtaining Institutional Review Board approval, we assessed 1,802 primary TKAs (1,496 patients) who received cefazolin alone or cefazolin combined with vancomycin for TKA-PJI prophylaxis. A detailed chart review was performed to determine patient demographic features (age, gender, BMI, American Society of Anesthesiologists Score), antibiotic selection, vancomycin administration timing, and 1-year PJI rates. Statistical assessment was accomplished using a two-sided Student's t-test or Fisher's exact test. Patients who received dual-antibiotic prophylaxis with “on time” vancomycin infusion (Group CVt) had significantly lower infection rates than other TKA patients (0.8 vs. 2.7%, p < 0.01). “On Time” vancomycin administration was associated with a lower TKA-PJI rate for patients with a BMI < 45 kg/m2 (0.5 vs. 2.6%, p < 0.01) with no infections in 120 TKA patients with a BMI between 40 and 44.9 kg/m2 (p < 0.01). No difference was noted for patients with a BMI ≥ 45 kg/m2 (3.3 vs. 2.6%, p = 0.71). There were no infections in 150 TKA patients with a normal BMI (18–25 kg/m2) in any PJI-prophylaxis treatment group. Adoption of a dual-antibiotic prophylaxis approach can successfully reduce TKA-PJI rates among overweight and moderately obese patients. The approach does not appear to influence outcomes for low risk patients with a normal BMI (18–25 kg/m2) or for higher risk patients with a BMI > 45 kg/m2.
Revision TKA for Instability: Poorer Outcomes after a Previous Aseptic Revision
Authors: Tegethoff Jason D. , Walker-Santiago Rafael , Ralston William M. , Keeney James A.
Published: January 2021

Instability is a common indication for early revision total knee arthroplasty (rTKA). The comparative performance of instability rTKA performed after primary TKA and instability rerevision TKA (rrTKA) performed after a previous rTKA performed for any aseptic indication have not been defined. This study was performed to determine the rate of adverse outcomes for patients undergoing aseptic instability TKA revision following a primary TKA or a previous aseptic any-cause rTKA. After obtaining Institutional Review Board approval, we retrospectively identified 126 rTKA and 28 rrTKA component revision procedures performed for an exclusive instability diagnosis between January 1, 2011 and April 30, 2018. We excluded patients undergoing isolated liner exchange, single component revision for mid-flexion instability, and patients treated with a constrained hinge. Patient demographic characteristics, medical comorbidities, time to initial revision TKA, and adverse postrevision outcomes (reoperation, component revision, infection, amputation) were assessed using paired Student's t-test or Fisher's exact test with a p-value < 0.05 used to determine significance. Patients in the rrTKA cohort were more commonly female (57.1 vs. 27.8%, p < 0.01), with no other demographic differences. The rrTKA cohort had higher reoperation (39.3 vs. 18.4%, p = 0.02) and component revision rates (25.0 vs. 8.7%, p = 0.03), with a trend towards early reoperation < 2 years after surgery (25.0 vs. 11.1%, p = 0.07). The rrTKA cohort also had higher adverse outcomes related to infection (14.3 vs. 1.6%, p = 0.01), extensor mechanism failure (14.3 vs. 3.2%, p = 0.04) and above-knee amputation (14.3 vs. 2.4%, p = 0.02). Component revision is beneficial for patients with TKA instability; however, higher adverse outcome rates occur after instability rrTKA performed after a previous aseptic any-cause rTKA. Infection prevention and extensor mechanism protection are important to minimize the most common adverse outcomes identified among patients undergoing aseptic rrTKA for instability.
Evaluation of Tibial Tunnel Location with the Femoral Tunnel Created Behind the Resident's Ridge in Transtibial Anterior Cruciate Ligament Reconstruction
Authors: Takahashi Tsuneari , Saito Tomohiro , Kubo Tatsuya , Hirata Ko , Sawamura Hideaki , Suzuki Takahiro , Takeshita Katsushi
Published: January 2021

Few studies have determined whether a femoral bone tunnel could be created behind the resident's ridge by using a transtibial (TT) technique-single bundle (SB)-anterior cruciate ligament (ACL) reconstruction. The aim of this study was to clarify (1) whether it is possible to create a femoral bone tunnel behind the resident's ridge by using the TT technique with SB ACL reconstruction, (2) to define the mean tibial and femoral tunnel angles during anatomic SB ACL reconstruction, and (3) to clarify the tibial tunnel inlet location when the femoral tunnel is created behind resident's ridge. Arthroscopic TT-SB ACL reconstruction was performed on 36 patients with ACL injuries. The point where 2.4-mm guide pin was inserted was confirmed, via anteromedial portal, to consider a location behind the resident's ridge. Then, an 8-mm diameter femoral tunnel with a 4.5-mm socket was created. Tunnel positions were evaluated by using three-dimensional computed tomography (3D-CT) 1 week postoperatively. Quadrant method and the resident's ridge on 3D-CT were evaluated to determine whether femoral tunnel position was anatomical. Radiological evaluations of tunnel positions yielded mean ( ±  standard deviation) X- and Y-axis values for the tunnel centers: femoral tunnel, 25.2% ± 5.1% and 41.6% ± 10.2%; tibial tunnel, 49.2% ± 3.5%, and 31.5% ± 7.7%. The bone tunnels were anatomically positioned in all cases. The femoral tunnel angle relative to femoral axis was 29.4 ± 5.5 degrees in the coronal view and 43.5 ± 8.0 degrees in the sagittal view. The tibial tunnel angle relative to tibial axis was 25.5 ± 5.3 degrees in the coronal view and 52.3 ± 4.6 degrees in the sagittal view. The created tibial bone tunnel inlet had an average distance of 13.4 ± 2.7 mm from the medial tibial joint line and 9.7 ± 1.7 mm medial from the axis of the tibia. Femoral bone tunnel could be created behind the resident's ridge with TT-SB ACL reconstruction. The tibial bone tunnel inlet averaged 13.4 mm from the medial tibial joint line and 9.7 mm medial from the tibia axis.
Four-Dimensional CT Analysis of Dorsal Intercalated Segment Instability in patients with Suspected Scapholunate Instability
Authors: Athlani Lionel , Granero Jonathan , Rouizi Kamel , Hossu Gabriela , Blum Alain , Dautel Gilles , Gondim Teixeira Pedro Augusto
Published: January 2021

Background In this study we sought to evaluate the contribution of dynamic four-dimensional computed tomography (4DCT) relative to the standard imaging work-up for the identification of the dorsal intercalated segment instability (DISI) in patients with suspected chronic scapholunate instability (SLI).

Methods Forty patients (22 men, 18 women; mean age 46.5 ± 13.1 years) with suspected SLI were evaluated prospectively with radiographs, arthrography, and 4DCT. Based on radiographs and CT arthrography, three groups were defined: positive SLI (n = 16), negative SLI (n = 19), and questionable SLI (n = 5). Two independent readers used 4DCT to evaluate the lunocapitate angle (LCA) (mean, max, coefficient of variation [CV], and range values) during radioulnar deviation.

Results The interobserver variability of the 4DCT variables was deemed excellent (intraclass correlation coefficient = 0.79 to 0.96). Between the three groups, there was no identifiable difference for the LCAmean. The LCAmax values were lower in the positive SLI group (88 degrees) than the negative SLI group (102 degrees). The positive SLI group had significantly lower LCAcv (7% vs. 12%, p = 0.02) and LCArange (18 vs. 27 degrees, p = 0.01) values than the negative SLI group. The difference in all the LCA parameters between the positive SLI group and the questionable SLI group was not statistically significant. When comparing the negative SLI and questionable SLI groups, the LCAcv (p = 0.03) and LCArange (p = 0.02) values were also significantly different. The best differentiation between patients with and without SLI was obtained with a LCAcv and LCArange threshold values of 9% (specificity of 63% and sensitivity of 62%) and 20 degrees (specificity of 71% and sensitivity of 63%), respectively.

Conclusion In this study, 4DCT appeared as a quantitative and reproducible relevant tool for the evaluation of DISI deformity in cases of SLI, including for patients presenting with questionable initial radiography findings.

Level of evidence This is a Level III study.
Response Function Simulation of Labr3 (Ce) Scintillation Detector
Authors: Fida M A , Liu Fang , Li Min , Jiang Tianze , Fan Xiaoxue
Published: January 2021

In Nuclear physics, gamma detection techniques are the most common ones being used for spectroscopy. Scintillation detectors find their applications in a large number of fields. The most commonly used and famous scintillation detector was NaI(Tl) that has been in use since the last 50 years. Recently, several new detectors have also been introduced commercially and they include lanthanum-based detectors. This study focuses on the response function simulation of the LaBr3(Ce) detector crystal. This is accomplished by developing a model that calculates various key properties for the detector crystal. This is done by using the Monte Carlo N-Particle (MCNP) transport code. A complete model for the detector is developed to simulate the lab setup. The simulation is then used to obtain the energy distribution of pluses that are created in the detector. Several gamma sources are used to obtain the pulse height spectra to calculate our properties of interest. The effect of distance on the spectra is also simulated. For Cs137 (662KeV), the energy resolution comes out to be 3.447% and FWHM is 22.12 KeV. An increase in the incident gamma energy results in increased FWHM whereas energy resolution and detection efficiency show a decreasing trend. After simulations, the crystal was also studied experimentally. In this case, both the simulation and experimental coincided. This proves the validity of the model developed.
Accuracy Evaluation and Modification Method for Estimating Point Light Spot Positions with Gaussian Fitting Algorithm
Authors: Mao Shuai , Shen Jin , Wang Yajing
Published: January 2021

This paper presents an accuracy evaluation method for point light spot position estimation with a Gaussian fitting algorithm combined with a centroid algorithm. Using centroid algorithm in the region around the Gaussian fitting distribution position estimation gets a position estimation value, and it is found that the deviation between this value and the Gaussian fitting algorithm position estimation approximately indicates the deviation between the Gaussian fitting algorithm position estimation and the real one. And at the basis of this finding, a modification method is proposed for position estimation with the Gaussian fitting algorithm. Experimental results show that the accuracy evaluation errors are less than 0.62 nm for 100- and 500-nm diameter fluorescent nanospheres, and the proposed modification method can enhance the accuracy by 3.1 nm.
Free Response Approach for the Second Order Partial Differential System with Time Periodic Coefficient
Authors: Huang Dishan , Liang Jiacheng , Xiao Liang
Published: January 2021

In this paper, a new method to approach the free response of the second order partial differential system with time periodic coefficient is presented with a special form of a trigonometric series with mode functions, and it can be expressed in a closed-form solution. As a result that the partial differential equation with time periodic coefficient can be transformed into a linear algebra equations, from which a characteristic equation can be obtained. Then, complex oscillation frequency and all harmonic coefficients can be computed. All arbitrary constants in a general solution can be obtained with initial conditions. Investigations show that the proposed approach not only computes free vibration with multiple modes with higher accuracy, but also it is suitable to analyze vibration instability. So this study is valuable for vibration analysis in an elastic continuum with time periodic coefficient.
Measurement of Black Hole Spin via X-ray Reflection Spectra
Authors: Gan Ling
Published: January 2021

The measurement of black hole spin is of great significance. The methods of measuring the spin have been discussed for a long time. For this important astrophysical problem, the paper begins with the significance of measuring a black hole spin and focuses on the theory of measuring the spin via the X-ray reflection recognized as iron line spectrum method. The paper also discusses the popular reflection models and explains the important parameters. Besides, the other methods of spin measurement are introduced, mainly comparing them with the X-ray reflection method. Finally, the advantages and disadvantages of the X-ray reflection method are summarized.
Perception of Sound Source Localization in Wave Field Synthesis
Authors: Zhao X , Meng Z H
Published: January 2021

The subjective perception of traditional spatial sound reproduction is limited by the position of the listener. Wave field synthesis (WFS) generate accurate sound reproduction in a large area by using speaker array without the limitation of the position of the listener. In the past, the research of WFS mainly focused on theoretical algorithm and simulation experiment. In this paper, the subjective location perception of sound source in actual WFS system is studied. The subjective experiments use three types of virtual sound sources with different distances and angles. It is found that distance has little effect on location perception overall. Subjective location perception is most accurate when the virtual sound source is 0 degrees. Perception of virtual sound source directions at 15 degrees, 30 degrees, and 45 degrees are all around 30 degrees, and the standard deviation of perception of virtual sound sources location at 45 degrees is largest. In terms of sound source type, there is not much difference between pure tone and narrow band noise.
The Optical Measuring System of Universal Time: Digital Zenith Tube
Authors: Cai Hongbing , Xu Jingsong , Chen Shaojie
Published: January 2021

Universal Time is one of the Earth Orientation Parameters, which reflects the Earth’s rotation. Universal Time is the necessary parameter to build up the connection between the celestial reference frame and the terrestrial reference frame. In present, to measure Universal time relies mainly on Very Long Baseline Interferometry technique, but the period of gaining the observing result is a few weeks later although its measuring accuracy is very high. For shortening the data period and cutting the cost of observations, National Time Service Center constructed the Digital Zenith Tube net. In this paper, we state the structure of Digital Zenith Tube, its observation principle, observing features, observing process, and the system composing of the observing net. The Digital Zenith Tube net can also measure the deflections of the vertical of local stations which is an important parameter in the geodesy.
Calculation of Electric Field Distribution in the Simulating Device for Animal Experiment
Authors: Sun Tong , Chen Tao , Xie Ziyin , Kim Hakbong
Published: January 2021

A main way to investigate the biological effects of 50Hz electromagnetic field is to conduct animal experiments by using the simulating device of 50Hz electromagnetic field. In order to determine the exposure strength of experimental animals in rearing cages in simulating device more accurately, the distribution of electric field should be simulated. Based on ANSYS, a software of finite element analysis, we simulated two-dimensional (2D) electric field distribution of the proposed simulating device of high voltage 50Hz electric field for a case when there were no rearing cages, and we validated those simulation results by comparison with actual measurements. Additionally, we simulated three-dimensional (3D) electric field distribution in the rearing cages for the cases when there was one rearing cage and when there were 8 rearing cages in the simulating device respectively. The simulation results showed that distribution of 50Hz electric field in rearing cage was not uniform when there were rearing cages in the simulating device, and the maximum difference was about 9kV/m. Therefore, based on the movement tracking of animals and the distribution of 50Hz electric field in rearing cages, the cumulative exposure dose of experimental animals could be determined accurately through integral method in order to increase the accuracy of experiments.
An Inversion Method for Geoacoustic Parameters of Multilayer Seabed in Shallow Water
Authors: Xue Yangyang , Lei Fuqiang , Zhu Hanhao , Xiao Rui , Chen Chao , Cui Zhiqiang
Published: January 2021

To solve the problem of obtaining geoacoustic parameters of multi-layer seabed in shallow water, a geoacoustic inversion method based on Bayesian theory is studied in this paper. In this study, the seabed is assumed to be a horizontal layered elastic medium, and the error function is established according to the sound pressure field in the water layer and bayesian theory. The global optimization algorithm is used to obtain the three target parameters of wave velocity, density and wave velocity attenuation in each layer of the seabed. The designed optimization method can correct the parameters in the process of finding the solution according to the physical characteristics of the upper and lower layers. The simulation results show that this method greatly improves the stability and accuracy of the inversion results for the multi-layer seabed model.
Noise Intensity Estimation Method Based on PCA and Weak Textured Block Selection for Neutron Image
Authors: Pan Yao , Qiao Shuang , Zhao Chenyi
Published: January 2021

Noise intensity estimation has a very important application in image denoising. In image processing, the denoising method can achieve an ideal denoising effect under the assumption that the Gaussian noise intensity in the image is known. But in real denoising applications, especially the neutron image, the noise level is unknown, which will greatly affect the denoising effect of neutron image processing. In this paper, a method which combined the principal component analysis with weak texture block selection is proposed for noise intensity estimation of neutron images. The experimental results show that the proposed method can accurately estimate the Gaussian noise in the neutron image. Compared with the existing noise intensity estimation methods, the qualitative and quantitative results show that the proposed method has higher accuracy and stability.
Signal Detection and Signal Source Integrated System Design
Authors: Lai Wanchang , Ma Hengxu , Wang Guangxi , Lin Hongjian , Huang Jinchu
Published: January 2021

A signal detection and nuclear signal generator is designed with a 7 and a half high-precision measurement module, high-precision reference source, and digital potentiometer, which integrates the measurement of three signals of bipolar high voltage, micro/high current, and large resistance. And precision adjustable voltage source and current source of microvolt level and picoamp level. Experimental tests show that the system can accurately measure a variety of IVR signals, while providing a stable and precise voltage source and current source, and is easy to operate and easy to carry.
Development of the Long Duration Chemical Oxygen Iodine Laser
Authors: Zhao Weili , Fang Benjie , Zhang Yuelong
Published: January 2021

The development of Chemical Oxygen Iodine Laser (COIL) with a long duration is of important for the industry application of COIL. The aim of this research was to achieve a stable and longtime COIL operation. A systemic study of output power stability was performed from three aspects: influencing factors, solutions, and experimental verification. A 100s duration COIL in the power level of 5kW was firstly developed in our laboratory. The fluctuant range of power is about 5%, and the filling factor f (Imin/Imax) is about 0.4.
Research and Application of Broadband Matching Technology for Single Crystal Underwater Acoustic Transducer
Authors: Li Haonan , Zheng Hong , Tang Yunfeng , Zhang Xufeng
Published: January 2021

To solve the broadband matching problem of underwater acoustic transducer, a matching method based on network theory analysis and Monte Carlo algorithm is studied in this paper. In this study, the network function expression is obtained by designing the matching network, and then the objective function is constructed. Monte Carlo algorithm is used to find the optimal solution of the matching network parameters to realize the broadband matching of a piezoelectric single crystal underwater acoustic transducer. By comparing the broadband matching of traditional piezoelectric ceramic transducer, the performance of single crystal material transducer is better after matching, that is to say, it can obtain good gain and broaden the frequency band at the same time. The whole matching process is simple and efficient, the matching effect is good. It provides a feasible reference for broadband matching of new single crystal underwater acoustic transducer.
Microchannel Heat Sink with High Thermal Conductivity Path for Diode Partially End-Pumped Slab Laser
Authors: Guo Zhanfeng , Wu Yongjin , Sun Yunna , Wang Yan , Ding Guifu
Published: January 2021

The thermal effect of diode pumped solid-state laser (DPSSL) has always been a main problem limiting the further improvement of laser performance. In this paper, based on the special heat load distribution of the laser crystal of diode partially end-pumped slab (Innoslab) laser, a multi-stage manifold rectangular microchannel heat sink (MCHS) with high thermal conductivity path (HTCP) is designed. The multi-stage manifold provides the MCHS more fluid-solid heat transfer area near the heat gathering area, while the HTCP provides a path for heat transmission from pump end to the body of MCHS. According to simulation calculation, the highest temperature of laser crystal has been reduced by nearly 50? due to the addition of HTCP. Then the MCHS is fabricated by MEMS technology and the laser crystal is replaced by simulated heat source. Compared with the MCHS without the HTCP, the thermal resistance of the MCHS with HTCP is reduced by 6.4%, which proves the effectiveness of HTCP in heat dissipation of Innoslab laser crystal.
Gamma Spectrum Measurement Following the Nuclear Decay
Authors: Shen Shuifa , Wang Feipeng , Yan Yupeng , Shen Jiejie , Li Yan , Jiang Haibing
Published: January 2021

In the present work, the detection systems and the data acquisition methods used in the nuclear decay study in our laboratory at Shanghai Institute of Applied Physics, CAS are introduced. These two detection systems include the low-background anti-Compton spectrometer and the three-parameter (γ-γ-t) coincidence system of HPGe-HPGe detectors, both of which are used to measure the γ rays following the nuclear β- and β++EC decays. In addition, as an example, the detection of γ rays following the β++EC decay of 74As, by using these two spectrometers, is described in detail.
Birdsong Recognition Based on Improved DTW
Authors: Jiang Hui , Qiao Qian , Zheng Hong , Wang Rui , Zhu Hanhao
Published: January 2021

In this study, the improved Dynamic Time Warping (DTW) algorithm is used in MATLAB to perform simulation classification and recognition simulation on the sounds of Nycticorax nycticorax and other 10 birds in the Wuzhishan Islands Reserve in Zhoushan, Zhejiang. By setting the slope of the path, the path is restricted in a fixed parallelogram. The algorithm combines with global restrictions can effectively speed up the path search, reduce the amount of calculation, reduce the memory requirements, reduce the recognition time, and thus improve the recognition efficiency. Experimental results show that compared with the traditional DTW algorithm, the improved DTW algorithm increases the recognition speed by 36.49%, the accuracy rate by 4.08%, and the recognition efficiency is greatly improved.
Geometrical Size Detection on Key Contours of Safety Seat Base
Authors: Chen Jiaxu , Lu Yonghua , Tan Jie , Ye Zhibin , Zhu Huayu
Published: January 2021

According to the plastic base without clear benchmark, the contour features are extracted by the image processing method such as image matching and feature extraction. With the reference of the waist groove, the measuring coordinate system is established. The coordinate transformation relation is determined by the calibration of visual inspection system. Thus, the geometric relation of the arc groove with respect to the measuring coordinate system is obtained. The geometric dimensions of the safety seat base are measured. The experiment result shows that the relative error of measuring the waist-shaped groove’s width is 2.7%, the one of measuring the length is 2.1%. And the relative error of measuring the arc-shaped groove’s width is 0.7%.
Research on the Maintenance Effectiveness Evaluation of Electronic Information Equipment
Authors: Cao Xianyuan , Wang Yande , Shi Zhiyong
Published: January 2021

An effectiveness evaluation model is provided considering the construction of effectiveness index system, index weight distribution and evaluation algorithm to help evaluate the electronic information equipment’s maintenance support effectiveness. The analysis results of an example demonstrate that the model effectively validates the effectiveness, reliability and consistency of the electronic information equipment’s maintenance support. Thus, it can work as the scientific basis of selections on the electronic information equipment’s maintenance support methods.
A Solution to an Extreme Value Problem in Discrete Geometry
Authors: Zhu Yuyang , Huang Jing , Yang Xingxing , Liu Xueling
Published: January 2021

Subdivide n-dimensional space En
into disjoint n-dimensional unit cubes, and let the set of these cubes be Λn. The vertices of each cube are called nodes. Let LPT
be the set of allcontinuous curve passing through node P(s1,s2
,…,sn)and nodeT(t1,t2
,…,tn) . ∀Γ ∊ LpT, α∊Λ
n
define the characteristic function of Γ to oc,

χ
Γ

(
α
)

=

{

0
,

when

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(

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)

=
0
,

1
,

when

μ

(

α
∩
Γ

)

>
0
,

Where μ(α ∩ Γ) is Lebesgue measure of point set α ∩ Γ. Name all its non-empty element as α
Γ(1),α
Γ(2),…,α
Γ(r(Γ)), and let λ
k(α
Γ(k)) be the weighting coefficients of α
Γ(k)(k=1,2…,r(Γ)) on Γ . This paper investigated the value of

Γ
∈

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P
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inf

{

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r

(
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(

α

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(
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(

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(
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, and by using discrete mathematics theory and construction method, proved that if all weighting coefficients are equal to 1, then max

{

m
1

,

m
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,
⋯

m
n

}

≤

Γ
∈

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P
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inf

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n

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Where

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|

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−

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, i = 1,2, …, n. The paper also generalizes the result to a wedge-shaped case.
Mode Analysis Theory of Small Disturbance Operation Process of Power System
Authors: Zhao Yuxiao , Wang Yang
Published: January 2021

The power system currently has the problem that transient steady-state low-frequency oscillations after the power system suffers from small disturbances will affect the normal operation of the power grid. This paper proposes a model analysis of engineering mathematics for the power system’s small-disturbance transient low-frequency oscillations. First, this paper constructs the mathematical model and simplified model of the power system. Next, this paper calculates the initial steady state of the model and builds a linearized model. Then small disturbances are added to the model in order to simulate the transient steady-state process of a single-machine infinite-bus system under real conditions. Finally, the power system stabilizer (Power system stabilizer PSS) is designed through model analysis. Compared the transient steady-state process the PSS isn’t installed and the PSS is installed in the singlemachine infinite power system, we can get experimental results, which show that the power system can obtain a new steady state after receiving small disturbances and eliminating small disturbances in time. At the same time, the installation of PSS can effectively increase the stability of the power system and the tolerance for the existence of interference.
Legendre Spectral Method for the 1-D Maxwell Equation
Authors: Fu Ying , Ma HePing
Published: January 2021

A time and space Legendre spectral method is established for the 1-D Maxwell equation, that is, both the time and the space are discretized by the Legendre-tau method. The specific scheme of the method and the implementation process of the algorithm are given. Also, the time multi-interval method is considered and the specific scheme is given.By taking appropriate basis functions, the unknown functions can be decoupled in computation. Numerical results show that the two methods are efficient.
Mammograms Classification Using ELM Based on Improved Sunflower Optimization Algorithm
Authors: Sun Yeheng
Published: January 2021

To assist specialists in detecting breast cancer on mammograms with better accuracy and less time consuming, this paper proposes an approach based on improved sunflower optimization algorithm (ISFO) and extreme learning machine (ELM). Firstly, features were extracted by using lifting scheme and gray-level co-occurrence matrix (GLCM). Then, the parameters of ELM were optimized by (ISFO) to obtain the final classification results. Finally, in order to avoid overfitting, the proposed model’s performance was evaluated with k-fold random stratified cross validation, and the experiments compared the model with other models on MIAS datasets. The experimental results show that the proposed model has higher classification accuracy, shorter learning time and stronger robustness on mammograms classification task. Thus, this method could be a promising application in bio-medical and provide a basis for the early diagnosis of breast cancer.
Efficient Green Fluorescent Organic Light-Emitting Devices with Stepwise Energy Levels
Authors: Zhao Xuesen , Mi Xiaoyun
Published: January 2021

In our work, efficient devices with double-EMLs with step energy based on green fluorescent emitter C545T were reported. Due to the matched energy, TcTa and 26DCzPPy were selected as the host materials of double-EMLs. The devices with double-EMLs displayed more excellent EL efficiency and higher brightness compared with devices with single-EML, which attributed to better balance of carriers, broadening recombination zone. Finally, efficient green EL device obtained maximum CE, EQE, PE and brightness of 10.13 cd/A, 2.8%, 9.36 lm/W and 11490 cd/m2.
Order amidst Disorder in 2D+3D Quantum Dragon Composite Nanodevices with varying Breadth
Authors: Novotny M. A. , Novotný Tomáš
Published: January 2021

A disordered quantum dragon nanodevice from a composite of 2D and 3D graphs is constructed. The nanodevice has a different number of atoms in every slice, in other words has a varying breadth. When connected to appropriate uniform semi-infinite leads, the device is shown to be a quantum dragon, namely the transmission probability is unity for all energies of incoming electrons. The device shows order amidst disorder, in that the local density of states as obtained from the Green’s function is ordered for the disordered device. For additional uncorrelated on site disorder in the tight-binding model, universal scaling of the average transmission is shown to be an effective analysis method.
Simulation of non-equilibrium critical behavior of the 3D isotropic and anisotropic Heisenberg models
Authors: Prudnikov V V , Prudnikov P V , Pospelov E A , Lyakh A S
Published: January 2021

Monte Carlo study of non-equilibrium critical behavior of three-dimensional Heisenberg model in isotropic case and with anisotropy of easy axis type is carried out. Relaxational Glauber-like dynamics of these models with evolution from high-temperature initial state is investigated. Realization of aging is demonstrated for two-time dependence of the autocorrelation function and dynamical susceptibility. Asymptotic fluctuation-dissipation ratios are determined for isotropic X
∞ = 0.383(6) and anisotropic X
∞ = 0.392(7) Heisenberg models. Significant influence of easy-axis anisotropy on non-equilibrium critical behavior of the 3D Heisenberg model leading to characteristics typical for the 3D Ising model is revealed.
Non-equilibrium phenomena in magnetic multilayer nanostructures and aging in magnetoresistance
Authors: Mamonova M V , Prudnikov P V , Prudnikov V V
Published: January 2021

A Monte Carlo simulation of the non-equilibrium behavior of multilayer magnetic structures Co/Cu(100)/Co and Pt/Co/Cu(100)/Co/Pt characterizing different types of magnetic anisotropy is realized. Simulation of transport properties gives possibility to reveal a nontrivial aging effects in the magnetoresistance of these structures and influence of initial states on two-time dependence of magnetoresistance.
Identification of a current-carrying subset of a percolation cluster using a modified wall follower algorithm
Authors: Akhunzhanov Renat K , Eserkepov Andrei V , Tarasevich Yuri Y
Published: January 2021

We have proposed and implemented a modification of the well-known wall follower algorithm to identify a backbone (a current-carrying part) of the percolation cluster. The advantage of the modified algorithm is identification of the whole backbone without visiting all edges. The algorithm has been applied to backbone identification in networks produced by random deposition of conductive sticks onto an insulating substrate. We have found that (i) for concentrations of sticks above the percolation threshold, the strength of the percolating cluster quickly approaches unity; (ii) simultaneously, the percolation cluster is identical to its backbone plus simplest dead ends, i.e., edges that are incident to vertices of unit degree.
Simulation of hysteresis phenomena in multilayer magnetic nanostructures
Authors: Prudnikov P V , Prudnikov V V , Saifutdinov I K
Published: January 2021

The Monte Carlo simulation of magnetic properties of artificial multilayer nanostructures in which ultrathin ferromagnetic films divided by layer of non-magnetic metal and coupled antiferromagnetically is realized. The anisotropic Heisenberg model is applied for description of magnetic properties. Dependence of hysteresis phenomena on thickness of ferromagnetic films and various values of interlayer exchange interaction is revealed. It is shown that horizontal sections appearing on the hysteresis loops are connected with magnetization flips of individual monolayers in ferromagnetic films. It is revealed that number of the hysteresis loops depends on interlayer interaction and temperature.
Statistical Analysis of Protein Side-chain Conformations
Authors: Ignatov Andrei
Published: January 2021

In the paper, three algorithms for predicting protein side-chain conformations are suggested and discussed. All proposed approaches analyze the local neighborhood of the target residue to avoid ‘steric clashes’. Strong and weak points of the algorithms are described, and ways of improving their outcomes are suggested. The approach based on predicting conformations for all residues in a protein chain segment appears to be the most promising.
Globule-coil transition in the dynamic HP model
Authors: Faizullina Kamilla , Burovski Evgeni
Published: January 2021

We consider a dynamic version of the HP model of a linear polymer: a self-avoiding walk on the square lattice, with monomers being either hydrophobic (H) or polar (P). We simulate the model in two dimensions in the grand canonical assemble via the Berretti-Sokal algorithm across the globule-coil transition and map out the phase diagram. Our results are consistent with the universality class of the transition being the same as the universality class of the theta-transition of an interacting self-avoiding walk.
Galaxy Clusters Reconstruction
Authors: Zarodnyuk A , Trofimova E , Solovyov A , Gradoboev D
Published: January 2021

In the present work, we introduce a machine learning-based approach for galaxy clustering. It requires to determine clusters to provide further galaxies groups’ masses estimation. The knowledge of mass distribution is crucial in dark matter research and study of the large-scale structure of the Universe. State-of-the-art telescopes allow various spectroscopy range data accumulation that highlights the need for algorithms with a substantial generalization property. The data we deal with is a combination of more than twenty different catalogues. It is required to provide clustering of all combined galaxies. We produce a regression on the redshifts with the coefficient of determination R
2 equals 0.99992 on the validation dataset with training dataset for 3,154,894 of galaxies (0.0016 < z < 7.0519). The application of a modern hierarchical density clustering algorithm for the separation of the groups of the galaxies allows us to obtain a result that is consistent with the work [4].
Computer Simulation of Station Keeping Costs of Halo Orbits in Sun-Earth system
Authors: Nugmanov Arthur , Bober Stanislav
Published: January 2021

Spacecraft missions to the collinear libration points of the Sun-Earth system have long proved scientific merit by providing valuable observational data. The unstable nature of the orbits around the mentioned points in space requires the development of control strategies for such missions in order to hold the spacecraft in vicinity of the libration points. We investigate a possible control strategy for the spacecraft on the halo orbits around the L1 and L2 collinear libration points aiming to evaluate the station keeping performance. The station-keeping strategy is based on the elimination of unstable component of motion by periodical velocity corrections performed in unstable directions. The simulations were performed in circular restricted three body problem. The impact of spacecraft position and velocity measurement accuracy, as well as the precision of the control maneuvers, on the station keeping costs, was calculated and studied. It was found that the measurement accuracy of the velocity components of motion and the precision of control burns implementation have the highest impact on the performance of the control strategy.
Investigation of Filtering and Sensing Properties of Complementary Metamaterial Resonant Cells by Computer Simulation
Authors: Skuridin A A , Yelizarov A A , Nazarov I V , Zakirova E A
Published: January 2021

In this paper we propose a resonant structure based on complementary metamaterial that can be used to control and monitor parameters of a material under test. We used CST Studio Suite to create a computer model of the proposed device and simulate it performance. The performance of the sensor is characterized by its scattering parameters that can be calculated by simulation. The results obtained are then analyzed and used to derive the relation between the sensor’s resonant frequency and the characteristics of the analyte. The proposed resonant structure and method can be used for nondestructive evaluation of dielectric substances, defect control, monitoring and measurement applications.
Algorithm for foam generation in plane
Authors: Klimenkova Olga , Shchur Lev
Published: January 2021

We propose a novel algorithm for the construction of the sparse, nonetheless the massive and rigid structure. The generated structures possess two significant properties reminiscent of the metallic foams. Firstly, the weight of the structures can be as low as the percent of the bulk one. Secondly, the structures are mechanically rigid. The structures are necessary for the simulation of the physical models of the foam properties.
Deep learning based methods for estimating distribution of coalescence rates from genome-wide data
Authors: Khomutov Evgeniy , Arzymatov Kenenbek , Shchur Vladimir
Published: January 2021

Demographic and population structure inference is one of the most important problems in genomics. Population parameters such as effective population sizes, population split times and migration rates are of high interest both themselves and for many applications, e.g. for genome-wide association studies. Hidden Markov Model (HMM) based methods, such as PSMC, MSMC, coalHMM etc., proved to be powerful and useful for estimation of these parameters in many population genetics studies. At the same time, machine and deep learning have began to be used in natural science widely. In particular, deep learning based approaches have already substituted hidden Markov models in many areas, such as speech recognition or user input prediction. We develop a deep learning (DL) approach for local coalescent time estimation from one whole diploid genome. Our DL models are trained on simulated datasets. Importantly, demographic and population parameters can be inferred based on the distribution of coalescent times. We expect that our approach will be useful under complex population scenarios, which cannot be studied with existing HMM based methods. Our work is also a crucial step in developing a deep learning framework which would allow to create population genomics methods for different genomic data representations.
Molecular dynamics simulations of the Ba+ ion mobility in liquid xenon
Authors: Ozerov Georgiy K. , Bezrukov Dmitry S. , Buchachenko Alexei A.
Published: January 2021

Improved molecular dynamics approach is proposed to simulate the mobility of atomic ion in the non-polar solvents such as liquefied rare gases. The many-body solvent polarization is described in the dipole approximation as the Car-Parrinello degrees of freedom of the Nosé-Poincaré-Anderson extended Hamiltonian function for NPT ensemble. Separation of the dipole induction from other ion-neutral interaction terms retained in the force field is accomplished by reparameterizing the accurate ab initio potential energies for di- and tri-atomic fragments. Effect of the external electric field is treated perturbatively, by reconstructing the trajectories at a finite external field from those propagated in the field-free case. Mobility definitions that use ensemble averages of ion velocity and field-induced dragging force are analyzed together with their Green-Kubo counterparts. The simulations of the Ba+ mobility in liquid Xe are in good agreement with the experimental data [Jeng S-C et al. 2020 J. Phys. D
42 035302].
On some problems of mathematical modeling of diffusion of non-equilibrium minority charge carriers generated by kilovolt electrons in semiconductors
Authors: Stepovich M A , Seregina E V , Kalmanovich V V , Filippov M N
Published: January 2021

Some problems of mathematical modeling of the diffusion of non-equilibrium minority charge carriers generated by kilovolt electrons in semiconductor targets are considered. The calculations were carried out by the matrix method, which makes it possible to solve the equations of heat and mass transfer in multilayer planar structures with an arbitrary number of layers. Estimates of the distributions of minority charge carriers in two-layer semiconductor structures of the "film-substrate" type are obtained.