bluuebunny/crossref_metadata_2025 huggingface dataset:
Macrophage activation syndrome in patients with adult-onset Still’s disease under tocilizumab treatment: A single-center observational study
Authors: Yamabe Toru , Ohmura Shin-ichiro , Uehara Koji , Naniwa Taio
Published: March 2021

Objectives

Macrophage activation syndrome (MAS) developed under tocilizumab treatment poses a diagnostic challenge. This study aims to demonstrate the frequency and the clinical features of MAS developed in patients with adult-onset Still’s disease (AOSD) receiving tocilizumab.

Methods

The consecutive AOSD patients treated with tocilizumab in our institution from April 2008 to March 2020 were studied. The frequency of clinically diagnosed MAS during tocilizumab treatment, their conformity to the several criteria relevant for MAS, and laboratory characteristics compared to AOSD flare were investigated.

Results

Of the 20 AOSD patients treated with tocilizumab, six developed clinically diagnosed MAS, four immediately after starting tocilizumab and two after long-term treatment. Some of them had already met the MAS criteria before starting tocilizumab. At MAS diagnosis, although some did not meet the MAS criteria due to lack of fever and/or the lower ferritin levels, all consistently showed sharp increases in ferritin along with marked abnormal changes in two or more different markers of organ damage, unlike the AOSD flares.

Conclusion

MAS is not a rare complication in AOSD patients receiving tocilizumab. The clinical similarities between systemic AOSD and MAS, and substantial alterations in MAS features by inhibition of interleukin-6 signaling may limit the utility of the existing diagnostic/classification criteria in diagnosing MAS under tocilizumab treatment. The emergence of abnormalities in MAS-related organ damage markers with a rapid elevation of ferritin should be considered as MAS development in AOSD patients receiving tocilizumab even if the patients are afebrile or have relatively low ferritin levels.
FXYD proteins and sodium pump regulatory mechanisms
Authors: Yap John Q. , Seflova Jaroslava , Sweazey Ryan , Artigas Pablo , Robia Seth L.
Published: March 2021

The sodium/potassium-ATPase (NKA) is the enzyme that establishes gradients of sodium and potassium across the plasma membrane. NKA activity is tightly regulated for different physiological contexts through interactions with single-span transmembrane peptides, the FXYD proteins. This diverse family of regulators has in common a domain containing a Phe-X-Tyr-Asp (FXYD) motif, two conserved glycines, and one serine residue. In humans, there are seven tissue-specific FXYD proteins that differentially modulate NKA kinetics as appropriate for each system, providing dynamic responsiveness to changing physiological conditions. Our understanding of how FXYD proteins contribute to homeostasis has benefitted from recent advances described in this review: biochemical and biophysical studies have provided insight into regulatory mechanisms, genetic models have uncovered remarkable complexity of FXYD function in integrated physiological systems, new posttranslational modifications have been identified, high-resolution structural studies have revealed new details of the regulatory interaction with NKA, and new clinical correlations have been uncovered. In this review, we address the structural determinants of diverse FXYD functions and the special roles of FXYDs in various physiological systems. We also discuss the possible roles of FXYDs in protein trafficking and regulation of non-NKA targets.
cMyBPC phosphorylation modulates the effect of omecamtiv mecarbil on myocardial force generation
Authors: Mamidi Ranganath , Holmes Joshua B. , Doh Chang Yoon , Dominic Katherine L. , Madugula Nikhil , Stelzer Julian E.
Published: March 2021

Omecamtiv mecarbil (OM), a direct myosin motor activator, is currently being tested as a therapeutic replacement for conventional inotropes in heart failure (HF) patients. It is known that HF patients exhibit dysregulated β-adrenergic signaling and decreased cardiac myosin-binding protein C (cMyBPC) phosphorylation, a critical modulator of myocardial force generation. However, the functional effects of OM in conditions of altered cMyBPC phosphorylation have not been established. Here, we tested the effects of OM on force generation and cross-bridge (XB) kinetics using murine myocardial preparations isolated from wild-type (WT) hearts and from hearts expressing S273A, S282A, and S302A substitutions (SA) in the M domain, between the C1 and C2 domains of cMyBPC, which cannot be phosphorylated. At submaximal Ca2+ activations, OM-mediated force enhancements were less pronounced in SA than in WT myocardial preparations. Additionally, SA myocardial preparations lacked the dose-dependent increases in force that were observed in WT myocardial preparations. Following OM incubation, the basal differences in the rate of XB detachment (krel) between WT and SA myocardial preparations were abolished, suggesting that OM differentially affects the XB behavior when cMyBPC phosphorylation is reduced. Similarly, in myocardial preparations pretreated with protein kinase A to phosphorylate cMyBPC, incubation with OM significantly slowed krel in both the WT and SA myocardial preparations. Collectively, our data suggest there is a strong interplay between the effects of OM and XB behavior, such that it effectively uncouples the sarcomere from cMyBPC phosphorylation levels. Our findings imply that OM may significantly alter the in vivo cardiac response to β-adrenergic stimulation.
Addendum: Measurement of emissivity in student laboratories (2020 Eur. J. Phys.
41 015101)
Authors: Ficker T
Published: March 2021

In the preceding paper Ficker (2020 Eur. J. Phys.
41 015101 https://doi.org/10.1088/
1361-6404/ab4c1e), two alternative methods for measuring emissivity of opaque grey diffuse materials have been presented. In both these methods, the contactless temperature measured by the infrared thermometer has been employed. The thermometer has been set at emissivity ɛ = 1 chosen in the settings menu of the thermometer. This ideal value has been incorporated into the derived relations determining emissivity of material samples. However, no infrared thermometer can work with such an ideal value due to the calibration restrictions during its manufacturing. Thus, a modification of the measured values of contactless temperatures is desirable. The present addendum specifies the corresponding modification of the contactless temperature used in the suggested experimental methods.
Novel double negative curvature elliptical aperture core fiber for terahertz wave transmission
Authors: Meng Miao , Yan Dexian , Yuan Ziwei , Feng Qinyin , Li Xiangjun , Qiu Guohua , Li Jining , Li Jiusheng
Published: March 2021

A novel double negative curvature terahertz fiber with elliptical tubes as cladding structure is designed and investigated. Six uniformly arranged elliptical hole tubes and six circular tubes are connected to each other as the cladding structure of the fiber. The confinement loss, bending loss, dispersion, and effective mode field area of the fiber are calculated in two different frequency regions. The simulation shows that the lowest confinement loss of 3.2 × 10−6 dB cm−1 can be achieved at 2.44 THz. The confinement loss is always in the order of 10−5–10−6 dB cm−1 in the frequency band of 2.22–2.5 THz. The waveguide dispersion of fiber remains between −0.18 and 0.05 ps/(THz × cm) in the frequency band of 2.04–2.4 THz. Moreover, the bending loss of 4.4 × 10−5 dB cm−1 can be obtained when the bending radius is 25 cm. The debut of this double negative curvature terahertz fiber, with combined advantages of ultralow confinement loss, low bending loss, low and flat dispersion and simple structure forebodes a new approach to completely release the potential of fiber in terahertz applications.
Phase-space sensitivity (weight functions) of 3 MeV proton diagnostics
Authors: Heidbrink W W , Garcia A , Boeglin W , Salewski M
Published: March 2021

The weight function W(X) is a diagnostic sensitivity to phase-space variables X that relates the measured signal C to the distribution function F(X) through the equation

C
=
∫
W
(
X
)
F
(
X
)
d
X

. In the present work, an algorithm to calculate W for a diagnostic that measures 3 MeV protons produced in d(d,p)t fusion reactions between a fast ion and a thermal deuteron is developed. The emitted protons escape the tokamak on curved orbits and are detected. These curved orbits constitute effective diagnostic ‘sightlines’. The presented algorithm accounts for the complications associated with these curved sightlines. An initial calculation of time-reversed proton orbits computes effective solid angles and sightlines for the relevant range of incident proton velocity vectors. These precomputed orbits are then used within the framework of FIDASIM (2020 Plasma Phys. Cont. Fusion
62 105008) to calculate the reactivity averaged over the thermal distribution of the ‘target’ deuterons and the probability that a fast ion of specified energy and pitch has a gyroangle that is consistent with the kinematic equations along each of the sightlines. Comparisons with analytic formulas and with independent calculations for the Mega Amp Spherical Tokamak 3 MeV proton diagnostic verify the algorithm.
High order plasmonic vortex generation based on spiral nanoslits
Authors: Fang Jing , Zhou Changda , Mou Zhen , Wang Shuyun , Yu Jiayi , Yang Yuanjie , Gbur Gregory J , Teng Shuyun , Cai Yangjian
Published: March 2021

Highly localized plasmonic vortices carrying orbital angular momentum are of importance for many applications. Yet, it is a challenge to generating plasmonic vortex with a high topological charge because of no available technique. Here, a novel plasmonic vortex generator is proposed based on spiral nanoslits etched in a metal film, which can produce a high order plasmonic vortex. The consecutive spiral nanoslit can generate plasmonic vortex with high intensity and the segmented nanoslits enhances the controllability of the plasmonic vortex, which are demonstrated numerically and experimentally. High order plasmonic vortex generation will broaden the prospects for plasmonic vortices in practical applications for nanomanipulation and nanofabrication.
A color image encryption algorithm based on an improved Hénon map
Authors: Gao Xiaohong
Published: March 2021

Chaos is widely used in secure communication and cryptography due to its randomness, unpredictability, non-periodicity and high sensitivity to initial values and parameters. However, there are many risks in some existing chaotic image encryption algorithms because they use the the chaotic map without complex dynamic characteristics. To overcome these weaknesses, in this paper introduced an improved Hénon map, and the dynamic analysis results show that the improved Hénon map has more rich chaotic behaviors and better complexity. In addition, we designed a color image encryption scheme using the improved Hénon sequences. For this encryption algorithm, color image is divided into R, G, B primary colors, then R, G, B primary colors are scrambled and diffused by the improved Hénon sequences. The simulation results illustrate that color image encryption algorithm security is advanced by usingimproved Hénon map.
The P-branch high-lying rovibrational transition spectral lines of BiLi molecule
Authors: Lei Jiao , Fan Qun Chao , Li Bao Lin , Fan Zhi Xiang , Fu Jia , Ma Jie , Xie Feng , Li Hui Dong , Xu Yong Gen
Published: March 2021

Starting from the classical expression of the rovibrational transition spectra of diatomic molecule, the Difference Converging Method (DCM) is used again to derive a new convenient and easy-to-use analytical formula for predicting the P-branch transitional spectral lines in the highly rovibrational excited states of diatomic molecule. Based on the limited experimental low-lying transition spectra the emission spectral lines up to the rotational quantum number

J
=
80

of (0–0) band in the

A

Π

3

A

2

0

+

→

X

3

∑

−

X

1

0

+

,

X

2

1

transition systems of BiLi molecule are predicted and studied. The accuracy of prediction is analyzed in detail by using the prediction error Δδ, which gives a quantitative conclusion for the reliability of prediction data. Compared the data obtained by DCM method with experimental ones, and analyzed the

v

E
x
p
t

−

v

D
C
M

,

Δ

E
x
p
t

,

Δ

D
C
M

,

Δ
δ

in deeply, the results show that the DCM method can use 11 known P-branch emission spectral lines to reliably reproduce the experimental values and accurately predict the high-excited transition spectral lines which may be difficult obtained in the experiment. It provides a new method to solve the problem of lack of high excited state transition spectra of diatomic molecules and the application of molecular spectrum in other fields.
Photoresponsive characteristics of EFG-grown iron-doped (100) Ga2O3 substrate with low dark current
Authors: Chu Xulong , Liu Zeng , Zhang Shaohui , Li Peigang , Tang Weihua
Published: March 2021

Low dark current is more desired in photodetector, that contributes to high photo-to-dark current ratio and high sensitivity. Therefore, in this paper, we use the edge-defined-film-fed (EFG)-grown iron (Fe)-doped Ga2O3 substrate to fabricate a solar-blind ultraviolet (UV) photodetector. Fortunately, the photodetector shows a low dark current of ∼10–13 A, which are more promised to advance the solar-blind photodetections. The responsivity (R) of 0.145 mA W−1, specific detectivity (D*) of 6

×

1010 cm Hz1/2 W−1 (Jones), linear dynamic region (LDR) of 75.56 dB and rise/decay time of 0.28 s/0.43 s are achieved in this Fe-doped β-Ga2O3 solar-blind UV photodetector.
Impact of internal-delensing biases on searches for primordial 𝖡-modes of CMB polarisation
Authors: Baleato Lizancos Antón , Challinor Anthony , Carron Julien
Published: March 2021

Searches for the imprint of primordial gravitational waves
in degree-scale CMB B-mode polarisation data must account for
significant contamination from gravitational lensing. Fortunately,
the lensing effects can be partially removed by combining
high-resolution E-mode measurements with an estimate of the
projected matter distribution. In the near future, experimental
characteristics will be such that the latter can be reconstructed
internally with high fidelity from the observed CMB, with the
EB quadratic estimator providing a large fraction of the
signal-to-noise. It is a well-known phenomenon in this context that
any overlap in modes between the B-field to be delensed and the
B-field from which the reconstruction is derived leads to a
suppression of delensed power going beyond that which can be
attributed to a mitigation of the lensing effects. More importantly,
the variance associated with this spectrum is also
reduced, posing the question of whether the additional power
suppression could help better constrain the tensor-to-scalar ratio,
r. In this paper, we show this is not the case, as suggested but not quantified in previous work.
We develop an analytic model for the biased delensed B-mode angular power spectrum, which suggests a simple renormalisation prescription to avoid bias on the inferred tensor-to-scalar ratio. With this approach, we learn that the bias necessarily leads to a degradation of the signal-to-noise on a primordial component compared to “unbiased delensing”. Next, we assess the impact of removing from the lensing reconstruction any overlapping B-modes on our ability to constrain r, showing that it is in general advantageous to do this rather than modelling or renormalising the bias. Finally, we verify these results within a maximum-likelihood inference framework applied to simulations.
Improving helium abundance determinations with Leo P as a case study
Authors: Aver Erik , Berg Danielle A. , Olive Keith A. , Pogge Richard W. , Salzer John J. , Skillman Evan D.
Published: March 2021

Currently, the primordial helium abundance is best estimated
through spectroscopic observations of H II regions in
metal-poor galaxies. However these determinations are limited by
several systematic uncertainties which ultimately limit our ability
to accurately ascertain the primordial abundance. In this study, we
improve the methodologies for solving for the reddening, the
emission contributions from collisional excitation of the H I
atoms, the effects underlying absorption in the H I and
He I emission lines, and the treatment of the blended H I and He I emission at λ3889 with the aim of
lowering the systematic uncertainties in helium abundance
determinations. To apply these methods, we have obtained
observations of the He I λ10830 emission line in the
brightest H II region in the extremely metal-poor (3%
Z⊙) galaxy Leo P with the LUCI1 instrument on the LBT. We
combine this measurement with previous MODS/LBT observations to
derive an improved helium abundance. In doing so, our present
analysis results in a decrease in the uncertainty in the helium
abundance of Leo P by approximately 70%. This result is combined
with data from other observations to estimate the primordial helium
mass fraction, Yp= 0.2453 ± 0.0034.
EEG-inception: an accurate and robust end-to-end neural network for EEG-based motor imagery classification
Authors: Zhang Ce , Kim Young-Keun , Eskandarian Azim
Published: March 2021

Objective. Classification of electroencephalography (EEG)-based motor imagery (MI) is a crucial non-invasive application in brain–computer interface (BCI) research. This paper proposes a novel convolutional neural network (CNN) architecture for accurate and robust EEG-based MI classification that outperforms the state-of-the-art methods. Approach. The proposed CNN model, namely EEG-inception, is built on the backbone of the inception-time network, which has showed to be highly efficient and accurate for time-series classification. Also, the proposed network is an end-to-end classification, as it takes the raw EEG signals as the input and does not require complex EEG signal-preprocessing. Furthermore, this paper proposes a novel data augmentation method for EEG signals to enhance the accuracy, at least by 3%, and reduce overfitting with limited BCI datasets. Main results. The proposed model outperforms all state-of-the-art methods by achieving the average accuracy of 88.4% and 88.6% on the 2008 BCI Competition IV 2a (four-classes) and 2b datasets (binary-classes), respectively. Furthermore, it takes less than 0.025 s to test a sample suitable for real-time processing. Moreover, the classification standard deviation for nine different subjects achieves the lowest value of 5.5 for the 2b dataset and 7.1 for the 2a dataset, which validates that the proposed method is highly robust. Significance. From the experiment results, it can be inferred that the EEG-inception network exhibits a strong potential as a subject-independent classifier for EEG-based MI tasks.
HAT ALARM SYSTEM TO PROTECT EYES, NOSE AND MOUTH FROM CORONA VIRUS CONTAMINATED HAND
Authors: Chatterjee Sarthak , Pal Saikat , Dey Sankha , Chowdhuri Swati , Sen Sabyasachi , Neogi Biswarup
Published: March 2021

Self-inoculation takes major part for the transmission of infections. Basically self-inoculation is nothing but a type of contact transmission. A person’s contaminated hands make contact with other parts of the body by Self-inoculation. Many infections mainly respiratory infections (e.g., influenza, coronavirus) can transmit via self-inoculation. In this pandemic situation it is very necessary to resist the transmission of infection (corona virus) via self-inoculation. In this paper a module of personal protective intelligent hat has been proposed for the protection of human being. The protective intelligent hat fabricates with two ends (i) Face Side End System (FSES) and (ii) Hand Side End System (HSES). FSES is made up with hall sensor whereas HSES is set up with magnet set ring or band. The novel corona virus enters the human body by eyes, nose and mouth when all are touched by infected hand. Avoid touching of contaminated hand is one of the key to survive from the attack of corona virus as well as other bacteria. The smart hat not only applicable to protect COVID-19, it is also applicable to protect various diseases which caused by contaminated hand like Influenza, Common cold, Chicken Pox etc.
Research on Power Quality Evaluation Method for High Energy-consuming Enterprises
Authors: Liu Yu , Liu Junde , Yang Bo , Ning Liaoyi , Zhu Xiangbo , Wang Xue , Bian Shenghua
Published: March 2021

With the increase of the voltage level of the power system, the demand for electric energy of high energy-consuming enterprises continues to increase, which puts forward higher requirements on the power quality. As power quality problems become more and more prominent, how to manage power quality scientifically and reasonably has attracted more and more attention from power quality workers. At the same time, users have increased their power quality requirements and the continuous development of power marketization. To achieve comprehensive power quality management, it is necessary to have a scientific, accurate, and standardized assessment of power quality. In-depth understanding and understanding of power quality, attach great importance to the harm and impact of power quality degradation on the operation of the power supply system, and it is particularly urgent to achieve comprehensive power quality management.
Application and Optimization Design of Titanium Alloy in Sports Equipment
Authors: Li Ming , Pan Yang , Zou Yunpeng
Published: March 2021

Titanium (Ti) was discovered in 1789. Norway and the United States began to produce titanium dioxide with the sulfuric acid method in 1908, the titanium sponge was prepared by the sponge titanium in the laboratory for the first time in 1910, and the United States Dupont company used the magnesium method to produce tons of titanium sponge in 1948, which marks the beginning of the industrial production of titanium sponge. Titanium and its alloys are one of the most promising light alloy structural materials in the 21st century due to their advantages of low density, high specific strength and specific stiffness, corrosion and fatigue resistance, high temperature resistance and weldability. In recent years, the world titanium industry and titanium processing technology has developed rapidly. The production and consumption of sponge titanium, wrought titanium alloy and ferroalloy processed materials have reached a very high level, and their application fields have been extended to almost all military and civilian industrial sectors. This paper focuses on the application of titanium alloy in sports equipment, and the optimization design of titanium alloy sports equipment.
Dynamic simulation method of adjustable nozzle considering clearance fit
Authors: Zhu Haitian , Jin Xin , Zhang Zhongqing , Zhou Kai , Li Chaojiang
Published: March 2021

Aiming at the motion stagnation and local damage failure of a 2D needled Cf/SiC adjustable nozzle during operation, the motion performance of the nozzle and the contact stress at the key parts were studied. A dynamic simulation method of the nozzle with adjustable nozzle considering clearance fit was established, and the throat contraction process was analyzed by a simulation example. Firstly, the critical analysis positions of the nozzle were determined by trial calculation, and the model was simplified and the mesh was optimized. Then, the simulation was carried out under the boundary conditions involving multiple fields. The motion characteristics of the nozzle throat during the throat contraction process were analyzed due to the velocity results, and the stress state and failure state at the key position of the nozzle during the impact process were finally determined.
The research of compressibility of compressed air foam
Authors: Chen Y , Chen T , Fu X C , Bao Z M , Hu C
Published: March 2021

The compressibility of compressed air foam was an important mechanical parameter in hydrodynamic calculations. The compression coefficient was set by the theoretical model in the current study of foam computational fluid mechanics. Here are many types of fire foam and each of them is different with different compressible performance. The compression coefficient obtained by theoretical calculation has a certain error and the experimental method test is needed. In this study, the equipment for measuring the foam compressibility was designed and developed. The compressibility of compressed air foam was preliminary studied in this article.
Analysis of Cracking Causes of P91 Welding Seam of High Pressure Steam Guide Pipe of Supercritical Unit
Authors: Li Xiuneng , Hou Shuang , Han Lizhe , Yan He , Yang Chao , Tian Zhiyong
Published: March 2021

A 600MW supercritical unit in a thermal power plant has been in operation for 63,000 hours, and a P91 weld leak occurred between the high-pressure steam guide pipe and the high-pressure governor valve. After macroscopic morphology analysis, alloy composition analysis, metallographic structure observation, and microhardness test analysis, it is found that the cracking of the base metal and weld on the high-pressure speed control valve is caused by structural stress and welding stress, which leads to cracking due to creep. The crack originated in the fine-grained area of the heat-affected zone, and it has been operating in a high-temperature operating environment for a long time. The P91 weld on the high-pressure steam guide tube produces creep holes in the fine-grained heat-affected zone, which gradually grow to form creep cracks, and eventually lead to cracks and leakage. Therefore, the failure of pipeline cracking is caused by the joint action of tensile stress and type IV crack.
Design and Control of High Precision two Axis Servo Scanning System in Space
Authors: Li Jing , Zhang Ai , Wang Qingying , Lin Zhe
Published: March 2021

A high precision direct drive control two axis servo scanning system in space is designed and developed. Based on the requirement of technical indicators, the high-precision direct drive control two axis servo scanning system is divided into an rotating telescope and a half angle mirror servo system. The design and analysis of the servo system’s structural design, shafting accuracy and motor options are carried out. Taking the half angle mirror servo system as an example, the electrical structure of servo system is expounded, and a compound control strategy based on all digital control drive and high precision photoelectric encoder is established, which directly drives PMSM. The circuit design and working process of servo control module are described in detail. The test results show that the speed stability performance of the scanning system can reach ±0.28%, and the servo precision can reach ±16″, and it has the characteristics of long life, anti pollution, etc, which can meet the requirements of the space high precision and long life scanning system.
Durability Test Bench Design for Electric Lock of Sliding Door
Authors: Yao Zhipeng , Lu Wei , Yao Jia , Lin Feng , Zhu Fengming
Published: March 2021

With the rapid development of automobile industry, electric door locks have widely used in various vehicle doors, especially for sliding doors. Among all performances, durability performance for electric locks is virtual for safety, so miniaturized durability test bench has been designed in the research according to the national standard of electric lock. Firstly, four-bar linkage mechanism has been adopted as the main actuator for the motion track achievement, the real motion track of sliding door can be guaranteed through the verification of ADAMS simulation. Secondly, the compression test has been carried out to calculate the reaction force of door sealing strips, thus the resistance device of test bench for simulating reliable locking process of electric lock has been designed. The miniaturized durability test bench can replace the existing durability test method which only performed by the whole vehicle testing, thus providing a low-cost and reliable test device for relevant manufacturers.
Identification Method of Key Risk Control Points in Mechanical Product Assembly Process
Authors: Ju Pinghua , Xu Wenlin , Gu Haodong , Ran Yan
Published: March 2021

In order to improve the assembly process quality of mechanical products, a structuralized decomposition method of Function-Movement-Action (FMA) was used to obtain the meta-action (MA) of minimum assembly granularity of mechanical products. Secondly, taking the performance index of the moving layer as the object of assembly process quality analysis, the state space model of the hybrid type MA was established, and the relationship models between the quality of the serial, parallel and hybrid type assembly process and the internal influencing factors were given. Then, the Partial Least Squares Regression (PLSR) method was used to solve the problem of multicollinearity and small sample among the influencing factors of each MA, and the key risk control points in the assembly process were obtained by the importance index analysis of variable projection. Finally, the effectiveness of the proposed method is proved by taking a numerical control turntable as an example.
Meshing efficiency analysis of double helical gears considering tribo-dynamic coupling effect
Authors: Wang Jietian , Lin Tengjiao , Yang Jin
Published: March 2021

In order to obtain accurate meshing efficiency of double helical gears, a calculation method of sliding friction power loss is proposed considering the tribo-dynamic coupling effect. Based on the mixed elastohydrodynamic lubrication (EHL) theory, the initial friction coefficient of tooth surface is obtained and the friction excitation is calculated. Considering the tribo-dynamic coupling effect, a sixteen-degree-of-freedom tribo-dynamic model of double helical gear pair is established, including time-varying mesh stiffness, friction excitation, backlash and transmission error. The tribo-dynamic behaviours of gear pair are analysed before and after coupling, and then the sliding friction power loss and meshing efficiency of double helical gears are obtained. The research results show that after tribo-dynamic coupling, the friction coefficient and friction excitation of double helical gear pair increase, and the meshing efficiency decreases. The meshing efficiency of gear pair increases with the increase of helix angle and pressure angle, and decreases with the increase of surface roughness.
Welding procedure Research of Niobium Heat Exchanger
Authors: Jiang Chengjun , Zhang Xiaoli , Du Yannan , Wang Wei
Published: March 2021

The weldability of R04200 niobium tube-to-tubesheet is analyzed. The macroscopic examination, penetration testing, hydrostatic testing and metallographic examination are tested by the method of GTAW. The results show that specific welding structures with He-Ar mixed gas as shielding gas can improve the arc stiffness, thermal efficiency and penetration. It expresses the great significance of formulating the welding methods guidance of niobium pressure vessels.
Design and Implementation of Ultrafast Broadband Sweep Source based on AD9914
Authors: Cai Kaida , Zhang Zhongyang , Huang Qingchun , Xiao Jing
Published: March 2021

To address a technical difficulty of long scanning cycle of broadband (100 MHz~900 MHz) frequency sweep source, an ultrafast broadband sweep source was designed based on the basic principle of direct digital-frequency synthesis (DDS) theory by using the high-performance DDS chip AD9914. During the design, the DSP28335 chip was used as the control device. The designed source can output 100MHz~900 MHz swept-frequency signals and it can realize sawtooth wave frequency-modulated signals in the shortest cycle (8us) by configuring the digital ramp generator in the chip. Moreover, a microstrip stepped impedance low-pass filter was designed using ADS to eliminate spurious signals in the direct synthesizer and decrease the in-band attenuation, thus making the curve flatter. According to final test and experimental data analysis, the designed sweep source has a large output broadband, short sweeping cycle and strong inhibition of spurious signals. It possesses great application values.
Optical Design of A CaF2-free 5× Flat-field Apochromatic Metallographic Micro-objective with Long Working Distance
Authors: Han Haimei
Published: March 2021

Based on the apochromatic system theory, an innovative CaF2-free 5× plan apochromatic metallographic micro-objective with long working distance was designed using the OSLO software through the iterative optimization technique. The designed metallographic microscope objective used the relevant photographic field lens as the initial structure. The final lens structure is composed of 7 lenses of 4 components in coaxial array. The object surface is imaged at infinity through an optical system. According to analysis results of the design, this metallographic microscope objective has following characteristics. Firstly, all lens are CaF2-free and manufactured by optical glass produced. Secondly, it can achieve flat-field chromatic aberration. Thirdly, it has a large field of view and long working distance.
Finite element reduction modeling and vibration analysis of mistuned coating thickness blisk
Authors: Kuang Ziqi , Shi Pingyi , Wu Zhengqiang , Bi Jun , Zhu Pailong
Published: March 2021

The application of hard coating damping technology to the blades ofblisk can effectively reduce the vibration stress and improve its service life. In this paper, a three-dimensional eight-node laminated incompatible element is proposed, which only needs the node coordinates of the structure without the coating. In the coating damping design process, it could avoid reconstructing the finite element mesh when changes the coating thickness. Based on the cyclic symmetry algorithm and the SNM method, a finite element reduction model to analyze the vibration characteristics of the coated blisk with coating thickness mistuning was established andverified by ANSYS. The results indicate that the proposed finite element model can be used to analyze the vibration characteristics with the changed coating thicknessand it shows great consistence with the result of ANSYS. On the other side, the SNM still has high accuracy when the coating thickness varies from 0 mm to 0.3 mm.
Experimental investigation and numerical simulation of the stress and deformation behavior for selective laser sintering of PA6
Authors: Zhou Mengyuan , Han Yuchen , Si Liang , Li Maoyuan
Published: March 2021

The uneven temperature field caused by the local instantaneous heating of the laser generates the thermal stress during the selective laser sintering. The stress causes the deformation of parts, affecting the precision and mechanical properties. However, it’s difficult to directly measure the stress history and deformation behavior during processing through experimental methods due to its ultra-high temperature and closed cavity. In this paper, the effects of laser power and scanning speed on the stress field and deformation of polyamide 6 by selective laser sintering were systematically investigated. The results showed that as the laser power increased or the scanning speed decreased, the z-direction stress and deformation of the specimens increased. Based on the inherent strain method, the deformation behavior of large-size parts was evaluated and in good agreement with experiments, which can guarantee the accuracy of the model and predict the deformation of parts.
Effects of External Heat Flux during Orbital Period of Spacecraft on Operating Characteristics of Loop Heat Pipe
Authors: Yang Tao , Zhao Shilei , Gao Teng , Zhao Zhenming , Zhang Ping
Published: March 2021

Effects of external heat flux during orbital period on operating characteristics of loop heat pipe were discussed through a thermal vacuum experimental study based on the orbit of remote sensing satellite. Results demonstrate that changes external heat flux of orbit causes periodic fluctuation of temperature on the heat delivery surface of loop heat pipe (LHP), thus causing period changes of state of working media in the LHP. Changes of state of working media further lead to “backflow” of working media, thus causing adverse impacts on stable operation of LHP. The adverse effects of backflow on operation of LHP were verified through a thermal vacuum experiment. Research conclusions have high guidance to the in-orbit application of LHP.
A False Bank Accounts Detection Method Based on Naive Bayesian Network
Authors: Wan Weiqing , Li Weihong
Published: March 2021

At present, more and more cases of economic fraud are based on false bank accounts. Due to the limitation of the bank’s technology and ability to verify the true identity of customers, the online verification system of banks can only check the authenticity of the ID card, while the consistent verification of people and cards can only be completed manually by bank tellers. It is easy to produce errors if the consistency is judged by the teller’s manual naked eye. In this paper was proposed a method of constructing a naive Bayesian network classification model by automatically detect the authenticity of bank accounts to avoid the problem of economic fraud of false bank accounts, and verified the feasibility of this method through specific examples. The experimental results show that the method which has certain theoretical and practical significance, and provides reference for the detection of other false accounts.
Research on modal analysis method of Multiple Units car body in the preparation conditions
Authors: Li Ya-Na , Li Shuo
Published: March 2021

The first-order vertical bending frequency is an important parameter to evaluate the vibration performance of car body in the preparation conditions. Increasing its frequency value can avoid the resonance between the car body and the bogie frame, reduce the vibration, and improve the running stability and riding comfort. Due to the low first-order vertical bending frequency, combined with layout optimization of equipment under vehicle and structure optimization, the optimal equipment layout scheme and the thickness of the key parts were obtained based on the refined modeling. The first-order vertical bending frequency of car body was increased from 7.63Hz to 8.35Hz, which was increased by 9.4%.
The Research and Implementation in Digital Transformation of Manufacturing Enterprises
Authors: Di Peng
Published: March 2021

This article introduces in detail the typical problems that exist in digital transformation of manufacturing enterprises. It describes the specific methods and strategies for manufacturing enterprises to achieve digital transformation from two aspects: the application of digital resources outside the enterprises and the internal value chain throughout the enterprise. Combined with the implementation case of a specific manufacturing enterprise, it demonstrates the process of the enterprise’s digital transformation.
Structure Optimization and Verification of Portable Intelligent Gauge Calibrator
Authors: Chen Hao , Sun Xiao Guang , Zhu Hui Chen
Published: March 2021

Portable intelligent gauge calibrator is a new type of gauge calibrator to replace the traditional gauge calibrator. It can effectively solve the problems of traditional gauge calibrator, such as unable to carry out on-site measurement, too large volume, low degree of intelligence and so on. In view of the problem that the maximum stress of the connector of the horizontal measuring platform is too large in the trial operation of the portable intelligent gauge calibrator, this paper puts forward a solution combining topology optimization with practical experience. The test shows that the method is effective and feasible.
Vibration synchronization intelligent control with trajectory tracking
Authors: Wu Shilling , Zhang Nan , Jia Yijun
Published: March 2021

Based on the dynamic model of the double-mass vibrating mechanical system, the adaptive control theory is introduced to study the motor control synchronization problem in the vibrating mechanical system. First, the dynamic model of the dual-mass nonlinear vibration system is studied, and the overall relationship between the motor motion and the vibration system is analyzed. Then, a dual-motor adaptive control strategy is designed, so that the parameters in the control system can be intelligently adjusted with the synchronization state of the motors, and the synchronization stability and motion trajectory between the motors are studied. Lyapunov stability criterion is used to verify the stability of the synchronous control system. Finally, MATLAB/Simulink is used to simulate the effectiveness of the dual-motor adaptive control system, which proves that the system has good robustness. Through research, it is found that the dual-motor vibration synchronization adaptive control strategy can keep the motors in the dual-mass nonlinear vibration system with good synchronization effects, and the system has good robustness. The research content can provide a certain theoretical reference for the research and design of multi-motor synchronous machinery.
A Contactless Measurement Instrument Based on Fusion of A Single-Point Laser Range Finder and A VIO System
Authors: Yuan Xinran , Liu Gang , Sun Boyang , Li Yanhui
Published: March 2021

To improve the safety and convenience of the traditional measurement instruments (such as Total station, Laser tracker), while reducing the system cost, a contactless measurement instrument consists of a single-point laser range finder (LRF) and a tracking module (a VIO system providing the measurement system 6DoF poses) is proposed in this paper. Its measuring procedure includes three steps: 1) Obtain the calibrated relative position parameters from a 3D position of the LRF. 2) Determine the remote target 3D point positions by fusing the measurement value of LRF. 3) In order to improve measurement accuracy, design a practical case-specific framework by analysing two typical measurement situations. This allows us to measure all scale factor information such as distance, height and clearance of a spatial structure in a convenient or portable way. Through the remote 3D point positions estimation experiment, the contactless measurement instrument exhibits the capability to satisfy the need of majority measurement applications for indoor architecture.
Effect of Volume Fraction Whiskers on Tensile and Thermal Expansion Properties of Mg2B2O5 Whisker-reinforced Aluminum Composite
Authors: Zhang Lei , Qiu Peng , Li Bin
Published: March 2021

This paper prepared magnesium borate whisker reinforced aluminum matrix composites by extrusion casting, and studied the effects of the volume fraction of the reinforced phase on the mechanical properties, thermal expansion properties and microstructure of the composites. The test results show that the reinforced magnesium borate whisker in the composite can be uniformly dispersed in the aluminum matrix to improve the strength. With the increase of the volume fraction, the strength of the composite material increases and the plasticity decreases. When the whisker volume fraction is 30%, the strength of the composite material reaches the maximum, with its tensile strength reaching 244 MPa and elastic modulus 107.6 GPA. When the whisker volume fraction is 20%, the composite has the best plasticity and the fracture elongation is 0.47%. The thermal expansion curve of the composite shows that the increase of whisker volume fraction will reduce the thermal expansion coefficient of the composite.
Research on Strengthening Process of Laser Additive Remanufacturing of Mill Housing
Authors: Huo Lijun , Zhang Yong , Qu Xiukun , Tang Rongjiang , Zhang Quanhong
Published: March 2021

Based on the analysis of the wear mechanism of the mill housing, the results show that the main failure forms of the mill housing are corrosion wear and stress wear. Therefore, it is proposed to remanufacture and repair the housing to improve the hardness and impact resistance of the wear part of the housing. In order to strengthen the wear resistance of the wear part of the housing, Fe45+5%WC alloy powder was prepared to strengthen the wear resistance of the worn part of the housing. The sample of the alloy layer was produced by high power semi-conductor laser, the hardness, impact toughness and surface PT were tested, and the microstructure was observed by metallographic and EDS experiments. The results show that the alloy layer has high hardness and wear resistance, and the grains are fine and the alloy layer is metallurgical bonded to the substrate. The 3500mm reversing mill housing was repaired by laser re-manufacturing technology, and it was found that the alloy layer had good bonding and surface hardness was improved, thus strengthening the housing.
A novel silicone rubber key automatic assembly system using placement machine
Authors: Ma Xiaosong , Zhang Yukun , Wu Keye , Tang Changhua , Ming Zihao , Zhong Zhengqi , Wang Hua
Published: March 2021

Silicone rubber key is an on and off component assembled on PCB. However, the assembly of silicone rubber key has been by manual and it is low efficiency and higher labor cost. In order to solve this problem a new assembly method by using the surface mount placement machine is invented. The main improvement of this new products is that human work can be completely replaced. And the advantage of the new invention is that the production line does not need to change for the surface mount assembly. The only change is the placement nozzle which is to suck the component and then assembly the silicone rubber key on the PCB. Furthermore, the newly designed vibration materials loading device is equipped to increase the production rate.
Enhanced the dielectric and tunable properties of Pb0.3Sr0.7TiO3 and (Bi1.5Zn0.5)(Nb0.5Ti1.5)O7 trilayer film through adjusting heat treatment process
Authors: Hou Shuang , Li Xiuneng , Ma Yijian , Tang Jianfu , Wu Xujing
Published: March 2021

Pb0.3Sr0.7TiO3(PST) and Bi1.5Zn0.5Nb0.5Ti1.5O7 (BZNT) thin films were deposited on Pt/Ti/SiO2/Si substrates by Sol-gel and radio frequency (rf) magnetron sputtering, respectively. The dielectric and tunable properties of thin films were investigated as a function of heat treatment processes. It’s found that the heat treatment process at the appropriate temperature and time can be used to obtain a good thin film. The film has the best comprehensive dielectric properties by annealing at 650°C for 45min, the figure of merit (FOM) is 20.1.
Effects of Stone-Wales and vacancy defects in fracture behavior of defective graphene
Authors: Zhang Cheng , Zhou Jiang , Zhang Cheng-Wei , Chen Xiao-Fei
Published: March 2021

Graphene has much higher mechanical strength than other materials, but can be significantly influenced by the vacancy defect or Stone-Wales defect in the lattices. In this paper, we use molecular dynamics simulation to study the effects of vacancy and Stone-Wales defects in fracture behavior of the defective graphene. The results show that the fracture strength of graphene is more sensitive to the vacancy defects than that of Stone-Wales defect. When the defect is located in the center of graphene, the fracture strength of defect graphene is less than that of defect-free graphene. When the defect is far away from the center of graphene, the fracture strength of defect graphene will be enhanced, even greater than that of defect-free graphene. This study may help to understand the properties of graphene with defect, but also show the potential for graphene-based materials in engineering.