bluuebunny/crossref_metadata_2025 huggingface dataset:
Chemistry, biochemistry and clinical relevance of the glutamine metabolite α-ketoglutaramate/2-hydroxy-5-oxoproline
Authors: Denton Travis T. , Cooper Arthur J. L.
Published: July 2023

In the glutaminase II pathway (which we now refer to as the glutamine transaminase-ω-amidase (GTωA) pathway), l-glutamine is transaminated to α-ketoglutaramate (KGM), which, in turn, is hydrolyzed to α-ketoglutarate and ammonia by an enzyme known as ω-amidase. Despite the fact that the GTωA pathway was discovered more than 70 years ago, and is widespread in nature, the pathway has received limited attention. This is partly due to the broad amino acid/α-keto acid specificity of the glutamine transaminases, which has led to confusion over nomenclature and in assigning precise biological roles. Secondly, the α-keto acid product of glutamine transaminases – KGM – has not, until recently, become available in pure form. Here, we briefly discuss the metabolic importance of the GTωA pathway in microorganisms, plants and mammals. We pay special attention to the chemistry of KGM and methods for its synthesis. We discuss the importance of KGM as a biomarker for hyperammonemic diseases. We provide evidence that the GTωA pathway satisfies, in part, ‘glutamine addiction’ in a variety of cancer cells. We show that the anti-cancer drugs 6-diazo-5-oxo-l-norleucine and l-azaserine are transaminase and β-lyase substrates of glutamine transaminase K, respectively. We suggest that there is a pressing need for the development of: (1) inexpensive and scaled-up procedures for the synthesis of KGM to facilitate research on the biological importance of the GTωA pathway in mammalian and human tissues and in agricultural research; and (2) potent and selective inhibitors of ω-amidase, both as anti-cancer agents and as a means for investigating the detailed enzyme mechanism.
The extracellular chaperone clusterin prevents primary and secondary nucleation of an amyloidogenic variant of β2-microglobulin
Authors: Kumar Manjeet , Cantarutti Cristina , Thorn David C. , Bellotti Vittorio , Esposito Gennaro , Wilson Mark R. , Ecroyd Heath , Carver John A.
Published: July 2023

Amyloid fibril formation by the extracellular protein β2-microglobulin (β2m) and its subsequent accumulation in periarticular tissues have been linked to dialysis-related amyloidosis. A natural variant of human β2m responsible for aggressive systemic amyloidosis contains an aspartate to asparagine mutation at residue 76 (i.e. D76N β2m), which readily forms amyloid fibrils in vitro under physiological conditions. In this study, we examined the role of the extracellular molecular chaperone clusterin in modulating D76N β2m fibril formation in vitro under physiological conditions. The presence of extrinsic charged amino acids modulated D76N β2m fibril formation, implying that electrostatic interactions are involved in the protein’s aggregation. Thioflavin T (ThT) and 1-anilinonaphthalene-8-sulfonate fluorescence assays indicated that clusterin interacts via hydrophobic and electrostatic forces with the monomeric, prefibrillar and fibrillar species of D76N β2m. As a result, clusterin was incorporated into D76N β2m aggregates during the latter’s fibril formation, as indicated by SDS-PAGE of depolymerised fibrils. SYPRO Orange and ThT fluorescence assays suggested that, compared to pure D76N β2m fibrils, those formed in the presence of clusterin are chemically more stable with a reduced ability to act as nucleation seeds. Detailed 15N NMR relaxation studies of mixtures of 15N-labelled β2m with clusterin confirmed that the chaperone interacts transiently and non-specifically with monomeric β2m. Clusterin inhibits both primary and secondary nucleation of D76N β2m fibril formation. In doing so, clusterin binds to D76N β2m fibrils and stabilises them to prevent possible fragmentation. In vivo, the multifaceted chaperone action of clusterin may delay, if not prevent, β2m amyloid proliferation and deposition in tissues.
Factors influencing fine-scale occupancy and detectability of an insular Atlantic Forest frog
Authors: Flynn Caroline Norén , Ferreguetti Átilla Colombo , Ardenghi Fusinatto Luciana , Almeida-Santos Marlon , Dias-Silva Fernanda , Bergallo Helena Godoy , Rocha Carlos Frederico D.
Published: July 2023

Context Species of the tropical frog Family Hylodidae tend to be restricted to streams and, hence, have a small occupancy area. Hylodes fredi (Canedo and Pombal 2007), a diurnal stream-dwelling species endemic to the Atlantic Forest in Ilha Grande, south-eastern Brazil, is one such species. Because of scarce population studies, it is also categorised as Data Deficient (DD) in the IUCN Red List. Previous studies on the habitat use by this species did not account for imperfect detection, which could have led to biased results. Aims We aimed to systematically describe the microhabitats occupied by H. fredi, by generating a fine-scale occupancy model while accounting for imperfect detection. Methods We sampled six streams where the species is known to occur. Perpendicular transects were established in each stream and further subdivided into 10 sampling plots. Single-species and single-season occupancy models were created with the UNMARKED R package, and model selection was performed on the basis of the Akaike information criterion. Key results We observed the species in 70 of the 275 sampled sites, which resulted in a naïve occupancy of 0.28 and detectability of 0.25. The best models suggest that H. fredi occupancy increases positively with rock cover and inversely with leaf-litter cover. Detectability reduced with an increase in leaf litter cover and varied with the air temperature. Conclusions We conclude that H. fredi occupancy is affected by the presence of rock and leaf-litter cover. The data indicated that the species is restricted to the stream channel and does not seem to occupy forested areas that are distanced from the stream margins. Implications Considering that H. fredi and many other congeneric species are listed as ‘Data Deficient’ in the IUCN Red List, it is important to define a threat category so as to conserve them. Many stream-associated species tend to have their occupancy overestimated, leading to an underestimation of their threat risk. This study systematically demonstrated that H. fredi has a strict and reduced occupancy, mostly limited to the stream margins, that should be considered when determining conservation efforts for this and ecologically similar species.
Single-cell profiling reveals unique features of diabetogenic T cells in anti-PD-1-induced type 1 diabetes mice
Authors: Collier Jenna L. , Pauken Kristen E. , Lee Catherine A.A. , Patterson Dillon G. , Markson Samuel C. , Conway Thomas S. , Fung Megan E. , France Joshua A. , Mucciarone Kyla N. , Lian Christine G. , Murphy George F. , Sharpe Arlene H.
Published: July 2023

Immune-related adverse events (irAEs) are a notable complication of PD-1 cancer immunotherapy. A better understanding of how these iatrogenic diseases compare with naturally arising autoimmune diseases is needed for treatment and monitoring of irAEs. We identified differences in anti-PD-1-induced type 1 diabetes (T1D) and spontaneous T1D in non-obese diabetic (NOD) mice by performing single-cell RNA-seq and TCR-seq on T cells from the pancreas, pancreas-draining lymph node (pLN), and blood of mice with PD-1-induced T1D or spontaneous T1D. In the pancreas, anti-PD-1 resulted in expansion of terminally exhausted/effector-like CD8+ T cells, an increase in T-bethi CD4+FoxP3− T cells, and a decrease in memory CD4+FoxP3− and CD8+ T cells in contrast to spontaneous T1D. Notably, anti-PD-1 caused increased TCR sharing between the pancreas and the periphery. Moreover, T cells in the blood of anti-PD-1-treated mice expressed markers that differed from spontaneous T1D, suggesting that the blood may provide a window to monitor irAEs rather than relying exclusively on the autoimmune target organ.
Physics-Informed Neural Network Method for Predicting Soliton Dynamics Supported by Complex Parity-Time Symmetric Potentials
Authors: Liu Xi-Meng , Zhang Zhi-Yang , Liu Wen-Jun
Published: July 2023

We examine the deep learning technique referred to as the physics-informed neural network method for approximating the nonlinear Schrödinger equation under considered parity-time symmetric potentials and for obtaining multifarious soliton solutions. Neural networks to found principally physical information are adopted to figure out the solution to the examined nonlinear partial differential equation and to generate six different types of soliton solutions, which are basic, dipole, tripole, quadruple, pentapole, and sextupole solitons we consider. We make comparisons between the predicted and actual soliton solutions to see whether deep learning is capable of seeking the solution to the partial differential equation described before. We may assess whether physics-informed neural network is capable of effectively providing approximate soliton solutions through the evaluation of squared error between the predicted and numerical results. Moreover, we scrutinize how different activation mechanisms and network architectures impact the capability of selected deep learning technique works. Through the findings we can prove that the neural networks model we established can be utilized to accurately and effectively approximate the nonlinear Schrödinger equation under consideration and to predict the dynamics of soliton solution.
Effects of quantum fluctuations on macroscopic quantum tunneling and self-trapping of a BEC in a double-well trap
Authors: Kh Abdullaev Fatkhulla , Galimzyanov Ravil M , Shermakhmatov Akbar M
Published: July 2023

In this paper, we study the influence of quantum fluctuations (QFs) on the macroscopic quantum tunneling and self-trapping (ST) of a two-component Bose–Einstein condensate in a double-well trap. QFs are described by the Lee–Huang–Yang (LHY) term in the modified Gross–Pitaevskii (GP) equation. Employing the modified GP equation in a scalar approximation, we derive a dimer model using a two-mode approximation. The frequencies of Josephson oscillations and ST conditions under QFs are found analytically and proven by numerical simulations of the modified GP equation. The tunneling and localization phenomena are also investigated for the case of the LHY fluid loaded in a double-well potential.
Prostate segmentation accuracy using synthetic MRI for high-dose-rate prostate brachytherapy treatment planning
Authors: Kang Hyejoo , Podgorsak Alexander R , Venkatesulu Bhanu Prasad , Saripalli Anjali L , Chou Brian , Solanki Abhishek A , Harkenrider Matthew , Shea Steven , Roeske John C , Abuhamad Mohammed
Published: July 2023

Objective. Both computed tomography (CT) and magnetic resonance imaging (MRI) images are acquired for high-dose-rate (HDR) prostate brachytherapy patients at our institution. CT is used to identify catheters and MRI is used to segment the prostate. To address scenarios of limited MRI access, we developed a novel generative adversarial network (GAN) to generate synthetic MRI (sMRI) from CT with sufficient soft-tissue contrast to provide accurate prostate segmentation without MRI (rMRI). Approach. Our hybrid GAN, PxCGAN, was trained utilizing 58 paired CT-MRI datasets from our HDR prostate patients. Using 20 independent CT-MRI datasets, the image quality of sMRI was tested using mean absolute error (MAE), mean squared error (MSE), peak signal-to-noise ratio (PSNR) and structural similarity index (SSIM). These metrics were compared with the metrics of sMRI generated using Pix2Pix and CycleGAN. The accuracy of prostate segmentation on sMRI was evaluated using the Dice similarity coefficient (DSC), Hausdorff distance (HD) and mean surface distance (MSD) on the prostate delineated by three radiation oncologists (ROs) on sMRI versus rMRI. To estimate inter-observer variability (IOV), these metrics between prostate contours delineated by each RO on rMRI and the prostate delineated by treating RO on rMRI (gold standard) were calculated. Main results. Qualitatively, sMRI images show enhanced soft-tissue contrast at the prostate boundary compared with CT scans. For MAE and MSE, PxCGAN and CycleGAN have similar results, while the MAE of PxCGAN is smaller than that of Pix2Pix. PSNR and SSIM of PxCGAN are significantly higher than Pix2Pix and CycleGAN (p < 0.01). The DSC for sMRI versus rMRI is within the range of the IOV, while the HD for sMRI versus rMRI is smaller than the HD for the IOV for all ROs (p ≤ 0.03). Significance. PxCGAN generates sMRI images from treatment-planning CT scans that depict enhanced soft-tissue contrast at the prostate boundary. The accuracy of prostate segmentation on sMRI compared to rMRI is within the segmentation variation on rMRI between different ROs.
Shape memory polymers enable versatile magneto-active structure with 4D printability, variable stiffness, shape-morphing and effective grasping
Authors: Yao Haojie , Yu Miao , Fu Jie , Zhu Mi , Li Yaping , Li Shixu , Gan Ruyi , Zhou Hengqing , Qi Song
Published: July 2023

Magneto-active structures with non-contact actuation, precise controllability, strong penetrability, and biological harmlessness have wide application prospects in the fields of soft robots, bionic engineering, medical treatment, and flexible transmission, among others. This paper presents the design of a magneto-active shape memory polymer (MASMP) based on a blending matrix of polycaprolactone and thermoplastic polyurethane. The aim is to enhance the environmental adaptability, manufacturability, and diversification of actuation modes of magnetic-active actuators. We conducted an analysis of the magnetic/thermal switchable mechanical properties and shape memory properties of MASMP. The results demonstrate excellent shape fixation and shape recovery rates, as well as excellent flexibility and magnetorheological effects. We fabricated flexible printing filaments with a uniform diameter by using a screw extruder, which enables high-precision 4D printing for MASMP. We printed several magneto-active structures, which demonstrated variable stiffness, shape-morphing, and shape memory capabilities. The shape-morphing performance is in good agreement with the simulation results of the design process. Furthermore, we successfully printed and assembled a flexible claw that exhibits an effective grasping and release function activated by a magnetic field. Finally, we developed a magneto-active structure with negative Poisson’s ratio, showing great potential for application in metamaterial structure.
Revisiting (2+1)-dimensional Burgers’ dynamical equations: analytical approach and Reynolds number examination
Authors: Alharbi Rawan , Alshaery A A , Bakodah H O , Nuruddeen R I , Gómez-Aguilar J F
Published: July 2023

Classical Burgers’ equation is an indispensable dynamical evolution equation that is autonomously devised by Burgers and Harry Bateman in 1915 and 1948, respectively. This important model is featured through a nonlinear partial differential equation (NPDE). Furthermore, the model plays a crucial role in many areas of mathematical physics, including, for instance, fluid dynamics, traffic flow, nonlinear acoustics, turbulence phenomena, and linking convection and diffusion processes to state a few. Thus, in the present study, an efficient analytical approach by the name ‘generalized Riccati equation approach’ is adopted to securitize the class of (2+1)-dimensional Burgers’ equations by revealing yet another set of analytical structures to the governing single and vector-coupled Burgers’ equations. In fact, the besieged method of the solution has been proven to divulge various sets of hyperbolic, periodic, and other forms of exact solutions. Moreover, the method first begins by transforming the targeted NPDE to a nonlinear ordinary differential equation (NODE), and subsequently to a set of an algebraic system of equations; where the algebraic system is then solved simultaneously to obtain the solution possibilities. Lastly, certain graphical illustrations in 2- and 3-dimensional plots are set to be depicted - featuring the evolutional nature of the resulting structures, and thereafter, analyze the influence of the Reynolds number Ra on the respective wave profiles.
Putting all the X in one basket: Updated X-ray constraints on sub-GeV Dark Matter
Authors: Cirelli Marco , Fornengo Nicolao , Koechler Jordan , Pinetti Elena , Roach Brandon M.
Published: July 2023

Sub-GeV dark matter particles can annihilate or decay producing e
± pairs which
upscatter the low-energy photon fields in the Galaxy and generate an X-ray emission (via the
Inverse Compton effect). Using X-ray data from Xmm-Newton, Integral, NuStar
and Suzaku, we derive new constraints on this class of dark matter (DM). In the
annihilation case, our new bounds are the strongest available for DM masses above 180 MeV,
reaching 〈σv〉 ≲ 10-28 cm3/s for m
DM ≃
1 GeV. In the decay case, our bounds are the strongest to date over a large fraction of the
considered mass range, constraining τ ≳ 1028 s for m
DM ≃ 1
GeV and improving by up to 3 orders of magnitude upon existing limits.
Transient acceleration after non-minimal M-flation preheating
Authors: Ashoorioon Amjad , Rezazadeh Kazem
Published: July 2023

Light massive preheat fields acquire a non-vanishing dispersion during parametric resonance from their quantum particle production. This in turn will modify the inflaton potential, which in some cases can induce a transient period of acceleration. We illustrate this phenomenon in the setup of non-supersymmetric non-minimal M-flation (non-𝕄-flation) which has some motivations from the brane compactifications in string theory. Implementing a lattice simulation by the LATTICEEASY code, we compute the potential correction term in our scenario and show that the modified term indeed causes the Universe to make a transition from the decelerated expansion to a temporary phase of acceleration. The correction term reduces to some extent the number density of the particles generated during preheating, but the efficiency of preheating remains still enough to have successful particle production after inflation. We also compute the spectrum of the gravitational waves (GWs) generated during preheating in our setup by using the LATTICEEASY code. Although the peak frequency remains almost the same, the inclusion of the correction term reduces the amplitude of the gravitational spectrum by almost one order of magnitude.
Spins of primordial black holes formed with a soft equation of state
Authors: Saito Daiki , Harada Tomohiro , Koga Yasutaka , Yoo Chul-Moon
Published: July 2023

We investigate the probability distribution of the spins of primordial black holes (PBHs) formed in the universe dominated by a perfect fluid with the linear equation of state p = wρ, where p and ρ are the pressure and energy density of the fluid, respectively.
We particularly focus on the parameter region 0 < w ≤ 1/3 since the larger value of the spin is expected for the softer equation of state than that of the radiation fluid (w = 1/3).
The angular momentum inside the collapsing region is estimated based on the linear perturbation equation at the turn-around time which we define as the time when the linear velocity perturbation in the conformal Newtonian gauge takes the minimum value.
The probability distribution is derived based on the peak theory with the Gaussian curvature perturbation.
We find that the root mean square of the non-dimensional Kerr parameter √〈a
2
*〉 is approximately proportional to
(M/M
H)-1/3(6w)-(1+2w)/(1+3w), where M and M
H are the mass of the PBH and the horizon mass at the horizon entry, respectively.
Therefore the typical value of the spin parameter decreases with the value of w.
We also evaluate the mass and spin distribution P(a
*, M), taking account of the critical phenomena.
We find that, while the spin is mostly distributed in the range of 10-3.9 ≤ a
* ≤ 101.8 for the radiation-dominated universe, the peak of the spin distribution is shifted to the larger range 10-3.0 ≤ a
* ≤ 100.7 for w = 10-3.
A consistent view of interacting dark energy from multiple CMB probes
Authors: Zhai Yuejia , Giarè William , van de Bruck Carsten , Valentino Eleonora Di , Mena Olga , Nunes Rafael C.
Published: July 2023

We analyze a cosmological model featuring an interaction between dark energy and dark matter in light of the measurements of the Cosmic Microwave Background released by three independent experiments: the most recent data by the Planck satellite and the Atacama Cosmology Telescope, and WMAP (9-year data). We show that different combinations of the datasets provide similar results, always favoring an interacting dark sector with a 95% C.L. significance in the majority of the cases. Remarkably, such a preference remains consistent when cross-checked through independent probes, while always yielding a value of the expansion rateH0consistent with the local distance ladder measurements. We investigate the source of this preference by scrutinizing the angular power spectra of temperature and polarization anisotropies as measured by different experiments.
Searching for Intragroup Light in Deep U-band Imaging of the COSMOS Field
Authors: McCabe Tyler , Redshaw Caleb , Otteson Lillian , Windhorst Rogier A. , Jansen Rolf A. , Cohen Seth H. , Carleton Timothy , Borthakur Sanchayeeta , Ashcraft Teresa A. , Koekemoer Anton M. , Ryan Russell E. , Nonino Mario , Paris Diego , Grazian Andrea , Fontana Adriano , Giallongo Emanuele , Speziali Roberto , Testa Vincenzo , Boutsia Konstantina , O’Connell Robert W. , Rutkowski Michael J. , Scarlata Claudia , Teplitz Harry I. , Wang Xin , Rafelski Marc , Grogin Norman A. , Lucas Ray A.
Published: July 2023

We present the results of deep, ground based U-band imaging with the Large Binocular Telescope of the Cosmic Evolution Survey field as part of the near-UV imaging program, UVCANDELS. We utilize a seeing sorted stacking method along with night-to-night relative transparency corrections to create optimal depth and optimal resolution mosaics in the U-band, which are capable of reaching point source magnitudes of AB∼26.5 mag at 3σ. These ground-based mosaics bridge the wavelength gap between the Hubble Space Telescope WFC3 F275W and ACS F435W images and are necessary to understand galaxy assembly in the last 9–10 Gyr. We use the depth of these mosaics to search for the presence of U-band intragroup light (IGrL) beyond the local universe. Regardless of how groups are scaled and stacked, we do not detect any U-band IGrL to unprecedented U-band depths of ∼29.1–29.6 mag arcsec−2, which corresponds to an IGrL fraction of ≲1% of the total group light. This stringent upper limit suggests that IGrL does not contribute significantly to the Extragalactic Background Light at short wavelengths. Furthermore, the lack of UV IGrL observed in these stacks suggests that the atomic gas observed in the intragroup medium is likely not dense enough to trigger star formation on large scales. Future studies may detect IGrL by creating similar stacks at longer wavelengths or by pre-selecting groups which are older and/or more dynamically evolved similar to past IGrL observations of compact groups and loose groups with signs of gravitational interactions.
Mixed-field effect at the hyperfine level of 127I79Br in its rovibronic ground state: Toward field manipulation of cold molecules
Authors: Bao 包 Zhengbin 正斌 , Wang 王 Defu 得富 , Shao 邵 Xuping 旭萍 , Huang 黄 Yunxia 云霞 , Yang 杨 Xiaohua 晓华
Published: July 2023

The mixed-field effect at the hyperfine level of the rovibronic ground state of the 127I79Br (X1Σ, v = 0, J = 0) molecule is computed on the J–I uncoupled basis of |JMJI
1
M
1
I
2
M
2〉, where J is the molecular total angular momentum excluding nuclear spin, MJ
is the projection number of J, I
1 and I
2 are the nuclear spins of the iodine and bromine atoms, and M
1 and M
2 are the projection numbers of I
1 and I
2, respectively. When the two applied electric and magnetic fields are parallel, the perturbations are rare and only one perturbation is observed in a relatively large field regime in our computation range. However, when the two fields are off-parallel, the perturbations increase significantly and some sublevels show the Feshbach-like resonance phenomenon. Therefore, such sublevels transit between weak-field seeking and strong-field seeking repeatedly, which can be utilized to enhance or suppress cold molecular collision and chemical reaction rates. Such behavior of the molecular hyperfine structure in the mixed off-parallel fields may also be utilized to construct an electric-field-assisted anti-Helmholtz magnetic trap for cold molecules and to realize evaporative cooling of cold molecules (sub-mK) into the ultracold regime (μK).
Inferring light responses of primate retinal ganglion cells using intrinsic electrical signatures
Authors: Zaidi Moosa , Aggarwal Gorish , Shah Nishal P , Karniol-Tambour Orren , Goetz Georges , Madugula Sasidhar S , Gogliettino Alex R , Wu Eric G , Kling Alexandra , Brackbill Nora , Sher Alexander , Litke Alan M , Chichilnisky E J
Published: July 2023

Objective. Retinal implants are designed to stimulate retinal ganglion cells (RGCs) in a way that restores sight to individuals blinded by photoreceptor degeneration. Reproducing high-acuity vision with these devices will likely require inferring the natural light responses of diverse RGC types in the implanted retina, without being able to measure them directly. Here we demonstrate an inference approach that exploits intrinsic electrophysiological features of primate RGCs. Approach. First, ON-parasol and OFF-parasol RGC types were identified using their intrinsic electrical features in large-scale multi-electrode recordings from macaque retina. Then, the electrically inferred somatic location, inferred cell type, and average linear-nonlinear-Poisson model parameters of each cell type were used to infer a light response model for each cell. The accuracy of the cell type classification and of reproducing measured light responses with the model were evaluated. Main results. A cell-type classifier trained on 246 large-scale multi-electrode recordings from 148 retinas achieved 95% mean accuracy on 29 test retinas. In five retinas tested, the inferred models achieved an average correlation with measured firing rates of 0.49 for white noise visual stimuli and 0.50 for natural scenes stimuli, compared to 0.65 and 0.58 respectively for models fitted to recorded light responses (an upper bound). Linear decoding of natural images from predicted RGC activity in one retina showed a mean correlation of 0.55 between decoded and true images, compared to an upper bound of 0.81 using models fitted to light response data. Significance. These results suggest that inference of RGC light response properties from intrinsic features of their electrical activity may be a useful approach for high-fidelity sight restoration. The overall strategy of first inferring cell type from electrical features and then exploiting cell type to help infer natural cell function may also prove broadly useful to neural interfaces.
Optimization and test of working parameters of cutting device of vegetable grafting machine
Authors: Wang Chao , Song Chengyuan , Song Jian
Published: July 2023

To improve the grafting productivity and the healing survival rate of later grafted seedlings, the cutting device of the cucurbit vegetable grafting machine was designed. The ear wood and stock in the suitable grafting period were selected as the experimental objects for the cutting test. The influence of different cutting methods based on the sticking method on the cutting quality was studied. Taking cutting speed, cutter angle, and blade thickness as test factors, cutting success rate, and stalk drawing rate as test indicators, the optimal working parameters of the cutting device were determined through actual operation tests. The test results show that the cutting effect is the best when the cutting speed of the cutter of the seedling cutting device for grafting is 140 mm/s, the cutting angle of the cutter is 60°, and the thickness of the blade is 1.5 mm.
The influence of different runner widths on the performance of micro Pelton turbine
Authors: Chen Xueqing , Guo Yuxing , Zhu Guojun
Published: July 2023

Pelton turbine can not only utilize the high head hydraulic resources but also recover the flow kinetic energy in the pipeline. It is more and more widely used. Thus, the research on improving the efficiency and performance of Pelton turbine is important. In this paper, Boltzmann method is used to study the influence of different runner widths on the performance of a micro Pelton turbine. And two micro Pelton turbines with runner widths of 25mm and 20mm are taken as the research object. Then turbine efficiency is calculated and the internal flow characteristics of micro Pelton turbine are analyzed. The results show that the runner width has obvious influence on the efficiency. When the runner width decreases from 25mm to 20mm, the turbine efficiency decreases by 1.16%. Besides, the turbulence area in the runner decreases, and the velocity decreases. But the turbulence intensity and vorticity in the runner is enhanced, which causes more serious hydraulic loss.
Simulation of N-type 100V TDMOS Device Characteristics
Authors: Wang Li , Liu Shengyi , Song Zhe , Tao Ruilong , Li Peiqi , Zhang Xilai
Published: July 2023

This paper mainly introduces the TDMOS (Trench Double Diffused MOSFET). Through the simulation of device process parameters, the influence of process parameters on device breakdown characteristics, transfer characteristics, and output characteristics are analyzed from seven aspects from the epitaxial layer thickness, resistivity, implant dose and energy of P body and NSD, trench depth, the spacing and depth of the trench in the terminal structure. Thus, the design standard with a breakdown voltage greater than 100V, a threshold voltage of about 3V, and a resistance lower than 124 mΩ·um2 is reached.
Finite element analysis of bevel gear tooth side clearance and fatigue characteristics under alternating torque
Authors: He Ping , Mao Hongyong , Jing Manjun , Ma Jun , Lu Jinjin
Published: July 2023

In this paper, the effect of different tooth side clearances on the fatigue characteristics of bevel gears under alternating torque is investigated using finite element analysis technology. The article first determines the structure form and main parameters of the bevel gear and completes the establishment of the three-dimensional model of bevel gear transmission. Then, based on the principle of finite element analysis, the fatigue characteristics of the bevel gear under different tooth side clearances are simulated by ANSYS workbench software. Next, according to the simulation results, the changes in service life and safety coefficient of bevel gear with tooth side clearances are analyzed, and the relevant conclusions are drawn. Finally, combined with the finite element analysis results, the axial adjustment amount of the bevel gear assembly of this project is guided, and the actual use effect is verified. The results show that when the tooth side clearance jn is taken in the range of 0.04·m∼0.08·m, the fatigue safety coefficient and service life of bevel gear gradually decrease with the increase of tooth side clearance jn.
Influence of Base Oil Molecular Structure on the Tribological Performance of Diesel Engine Cylinder Liner and Piston Ring
Authors: Wang Weiwei , Yu Miao , Ma Jiandong , Jia Yuanming
Published: July 2023

Highly intensified diesel engines lead to severe lubricating condition, high performance lubricant is important to solve this problem. Base oil is the main composition of lubricant, which plays important role in lubricating performance. In this paper, three kinds of poly-α-olefin (PAO) base oil were prepared. Different olefin materials were used to produce PAO with different molecular structure. The tribological performance of diesel engine cylinder liner and piston ring lubricated with different base oil were evaluated by reciprocating test rig. Results show that PAO base oil synthesized with long carbon chain olefin has high viscosity index. The PC12 reduced the friction coefficient by 15.4%/19.6% in low speed/high speed friction compared with PC8. The wear of PC12 reduced 15.8% compared with PC8. The results were resulted from the long carbon chain of PC12, which produce high viscosity in high temperature and shear thin effect in high speed friction.
Particulate Matter Load Estimation and Distribution Characteristics of Diesel Particulate Filter
Authors: Wang Jiguang , Xu Feng , Wang Li , Chen Xudong , Chen Qiuling , Han Fei , Huang Youxian , Li Xuan , Xu Qingyun , Ge Yu , Gu Wangwen , Dai Xinghai
Published: July 2023

This paper focuses on the offline electric heating regeneration technology of DPF (Diesel Particulate Filter). Based on the actual operating conditions of the airport passenger elevator, the pressure drop changes before and after the offline regeneration of DPF, the passive regeneration process during the vehicle operation, and the capture efficiency of PM and PN after the offline regeneration of DPF are studied. The DPF pressure drop increases with the operation time because of the extremely low efficiency of passive regeneration before offline regeneration, and the initial pressure drop after regeneration is slightly higher than that of the fresh carrier due to the existence of ash. When the exhaust temperature reaches 420°C, the DPF passive regeneration rate is higher than the capture rate, and the DPF pressure drop drops rapidly when the passenger elevator continues to run. The mass fraction of fine particulate matter is more than 0.02μm in the cold start stage, while the mass fraction of fine particulate matter is more than 0.02μm in the hot start stage.
Research and Design of Arc Welding Parameters Control and Environment Monitoring System Based on DSP
Authors: Lu Lihui , Li Shuanghu , Guo Yingying , Si Pengcheng
Published: July 2023

In the process of the welding operation, a large number of welding smoke, toxic gas, and other pollutants will be produced, which can cause a variety of respiratory diseases. Therefore, the welder’s health is affected and the atmospheric environment is polluted. To monitor the detrimental soot substances produced in the arc welding process, an arc welding parameters control and environmental monitoring system was built by taking high-performance DSP (Digital Signal Processor) TMS320F2812 as the control core, which uses wireless communication technology. Multi-information sensing and welding parameters control can be carried out through the system in the arc welding process. The concentration of welding smoke, harmful gas, and other substances in the arc welding environment can be monitored in real time and the real-time environmental conditions are displayed visually. The functions of audible and visual alarms, automatic ventilation, and telecommunication are provided by the system. A lot of experimental verification and debugging results show that parameters control in the arc welding process and the monitor welding environment in real time could be realized by the built system and is running well.
Study on Difference of Gold Content Results of Electroplated Hard Gold Products
Authors: Yang Tingting , Wang Xuan , Zhu Yong , Yang Xihan , Li Lansen , Huang Wei , Li Simeng , Xu Tianchen , Li Miao , Wu Jing , Deng Junfa , Shen Jiani
Published: July 2023

The results of inductively coupled plasma spectrometry (ICP) and fire assay for the determination of gold content in electroplated hard gold products were compared, and the reasons for the differences were explored by transmission electron microscope, differential scanning synchronous thermal analyzer, high-frequency infrared carbon sulfur analyzer, etc. The result shows that the difference between the results of inductively coupled plasma spectrometry and fire assay is mainly due to the deposition of light elements such as K and Na and non-metallic elements such as C and S in the electroplating process caused by the complex electroplating liquid system. The above elements are not involved in the test of inductively coupled plasma spectrometry, so the final gold content is higher than the true value.
Study on The Method for Predicting The Explosion Source Point Based on The Characteristics of Shock Wave
Authors: Hou Feiyu , Wang Changli , Zhang Xin , Tian Haocheng , Li Kang , Bai Fengtao
Published: July 2023

To improve the accuracy in predicting the blast initiation position in tests from the measured data, a method of computing the blast source coordinates based on the average velocity of the blast shock and the corresponding correction and iteration methodology is proposed, and the accuracy of the method is verified and validated by comparing with the available data. The results show that: the accuracy of the method is good and its reliability is also high, and a spherical charge data correction method is proposed based on the characteristics of the shock wave, which can effectively improve the prediction accuracy. Using it, the coordinate error of the explosion source point is reduced from 0.656m to 0.084m, and the maximum relative error is reduced from 4.95% to 0.31%. The coordinate error of the dynamic explosion example is 1.68m, and the maximum relative error is 16.1%. The study found that the error of the original data has a great influence on prediction accuracy, and to ensure the high accuracy of the prediction results, the data with excessive errors should be excluded.
Research on Reliability of CNC Machine Tools Based on Sectional Model Involving Two Weibull Distributions
Authors: Chen Bingkun , Wang Zhiqiong , Zhang Yingzhi
Published: July 2023

To study the failure distribution rule of CNC machine tools and accurately fit the distribution model of failure time, the field test failure data from a series of CNC machine tools are analyzed in this paper. A sectional model involving two Weibull distributions is used to fit the failure time of CNC machine tools. The D-test method is used to examine the fit of the model. By comparing the goodness of fit with the ordinary Weibull distribution model, it is finally verified that the sectional model involving two Weibull distributions is more consistent with the failure data distribution rule of the CNC machine tools.
Research on Non-contact Bolt Preload Monitoring Based on DIC
Authors: Liu Zhenyao , Wang Decheng , Cheng Peng , Zang Yong
Published: July 2023

Bolt preload is a key parameter of the reliability of bolt connection. Traditional bolt preload detection generally uses torque wrench or high-precision strain sensor. In this paper, a new method of non-contact preload monitoring is realized by measuring the digital image of bolt elongation. A bolt tensile test device is designed, and the results of laser triangulation and three-dimensional point tracking are compared with those of optical measurement. The embedded load cell is used to monitor the bolt preload. The test results of M18 bolts with different bolt lengths and grades are evaluated. and it is found that the test values are close to the theoretical calculation, which can be used to predict the pretightening force.
Numerical simulation of the extruded process of Cased Telescoped Ammunition
Authors: Li Xiaofeng , Liang Lin , Mei Shuai
Published: July 2023

Compared with traditional guns, the cartridge belt of the Cased Telescope Ammunition (hereinafter referred to as CTA) is far away from the rifling when it is fired, which leads to a greater impact force in the process of extrusion, and further affects the barrel life and internal ballistic performance. A finite element model of the coupled projectile launching dynamics was established based on the elastic-plastic theory to study the mechanical characteristics of the extrusion process. The dynamic extrusion process of the conventional and CTA artillery projectile was simulated numerically, the corresponding data such as the extrusion velocity, extrusion resistance and the stress in the slope chamber were obtained, and the extrusion characteristics of the CTA artillery projectile were compared and analyzed. The results show that compared with the conventional artillery of the same caliber, the extrusion velocity and the extrusion resistance of the CTA guns are increased by 87.6% and 33.5%. The calculated results can provide a theoretical reference for the internal ballistics and structural design of the CTA guns.
Simulation of Auto Parts Polishing Control Strategy Based on PID Control
Authors: Tian Haopeng
Published: July 2023

With the large increase in automobile production, the demand for automobile parts is also increasing day by day. Aluminum alloy is the most widely used material in automobile parts. The production process of aluminum alloy parts has been automated, but the polishing process is still mainly manual. The high cost and low efficiency of manual polishing restrict the development of parts production technology. Therefore, it is imperative to develop a set of automatic polishing systems for aluminum alloy parts. Robot application in the polishing field has become a trend, but the force/bit coupling relationship in the polishing process of a robot is complicated, which brings great difficulty to the control of the polishing force. To solve the above problems, the key to obtaining stable polishing quality is to realize the force/bit decoupling of robot polishing and control the output constant polishing force. In this paper, an end-effector is used to realize the decoupling of force and position, and a new constant-force polishing control strategy is proposed to improve the automatic control level of robot polishing aluminum alloy auto parts. According to the nonlinear characteristics of the end-effector mathematical model and the feedback linearization characteristics of the backstepping method, a new type of backstepping PID constant force controller is designed, and the control flow is set up for simulation analysis. Simulink was used to build the simulation process and set up a reasonable controller gain for simulation verification. The simulation results of end-effector output polishing force under different strategies show that the reverse PID control has better response speed and anti-interference ability than the simple reverse control.
Fault Diagnosis Method of Planetary Gearbox Based on ISSA-VME and Multi-scale Fuzzy Entropy
Authors: Li Rongda , Xu Ke , Zhang Qing , Zhu Haifeng
Published: July 2023

To solve the problem of noise interference and difficulty in feature extraction of vibration signals of planetary gearbox, propose a fault diagnosis method of planetary gearbox based on improved sparrow search algorithm optimized variational mode extraction (ISSA-VME) and multi-scale fuzzy entropy (MFE). The vibration signal was decomposed by ISSA-VME, and the multi-scale fuzzy entropy of the original signal was calculated according to the IMF component. The fault feature set composed of MFE was applied to the SVM classifier optimized by the improved sparrow search algorithm for fault pattern recognition. The experimental results demonstrate that compared with ICEEMDAN and VMD methods, ISSA-VME has a better effect and higher efficiency on vibration signal decomposition. The identification rate of missing teeth, cracks, wear, and other faults of planetary gearbox sun gear by the proposed method reaches 97.50%.
Kinematics and Dynamics Simulation of Lower Limb Exoskeleton Walking Assist Mechanism
Authors: Zhao Yixuan , Li Haonan , Li Zheng , Wu Shuqin , Wang Yiming , Chai Chenwen
Published: July 2023

To solve the problem of rehabilitation training for patients with limited mobility of lower limbs, a scheme of lower limb exoskeleton walking assistance mechanism was proposed. The D-H model of the walking assist mechanism is established, and the forward kinematics is solved. The exoskeleton workspace is analyzed by the Monte Carlo method. The kinematics and dynamics simulation analysis of the walking assist mechanism is completed by using ADAMS software, and the rationality of the kinematics and dynamics performance is verified. The results show that the lower limb exoskeleton walking assist mechanism can meet the requirements of movement space, movement performance, and dynamic performance of patients with lower limb movement limitation and meet the basic needs of normal human wearing. The research results lay a foundation for the structural optimization of the following lower limb exoskeleton walking assist mechanism.
Machining Accuracy Allocation of Shaft System Considering Vibration and Cost
Authors: Shi Zhenyi , Sun Tao , Ma Zhenlai , Yu Wanbo , Shu Peng , Zhang Ji
Published: July 2023

In some important equipment such as vessels, the requirements for vibration reduction and cost-effectiveness of centrifugal pumps are becoming more and more stringent. It becomes really essential to present a method to assign manufacturing accuracy for shaft system assembly considering vibration and cost. A numerical model of the pump shaft system is developed to analyze the residual unbalance of the pump shaft system. The finite element model was verified through prototype tests. A machining accuracy allocation scheme is proposed by using an orthogonal design, and the cost and vibration intensity of the shaft system generated by vibration are evaluated. Based on this, a method to distribute shaft system machining accuracy is proposed to control the cost as much as possible while ensuring the vibration. Through orthogonal design, multiple sets of key parameter combinations are obtained, the vibration response of the shaft system under the parameter combination is calculated, and the contribution of each shaft system error to the shaft frequency vibration is analyzed. Combining the relative machining cost of the shaft system under different parameter combinations, the optimal allocation of the key parameters of the shaft system is completed based on vibration evaluation and relative cost.
Design and Analysis of A Two-stage Bionic Flapping Wing Aircraft
Authors: Fu Xiaokun , Hao Yongping , Ma Minghui , Zheng Xuyang
Published: July 2023

To develop an aircraft with a certain load capacity, high lift, and high bionics, a two-stage bionic flapping wing aircraft was designed according to the physiological structure of large birds. Firstly, the degrees of freedom of the transmission mechanism of flapping wing aircraft are calculated, and the dimensions of each component of the aircraft are determined. Secondly, we use the design software NX to draw the three-dimensional model of the aircraft. Then, the ADAMS software is used to simulate the dynamics of the aircraft, and the flapping amplitude and angular velocity changes during the flapping process are obtained, which verifies the rationality of the three-dimensional model design of the aircraft. Finally, a prototype of flapping wing aircraft is made. Experiments show that the flapping wing aircraft designed has good flapping stability. And the expectation is realized.
Study Effect of HIP & Heat Treatment on MIM Porous Tool Steel SKD11
Authors: Wu Xiaowei , Lan Fang
Published: July 2023

Hard tool steel SKD11 had a lot of industrial practical applications because it had super mechanical properties such as wear resistance and toughness. There is a trend to manufacture components with competitive costs. The wear resistance and hardness of the sintered components are insufficient to meet the cutter and dies’ strict requirements. The HIP process can further reduce pore size, quantity, and even distribution of pores of as-sinter blanks. As a result, the higher density, lower porosity, and high hardness of components can be obtained without obvious growing of grain size. After heat-treatment and subzero treatment, hardness increased up to HRC58-61, and wear resistance significantly improved.
Optimal Design of Stepping Self-moving Belt Tail
Authors: Hu Kaiyu , Yang Kangxin
Published: July 2023

This paper introduces the tail part of the belt conveyor, which is used to transport materials during the operation of the heading face and its forward form is a step forward. A bridge conveyor transfer machine is carried above the frame of the stepping self-moving belt tail, which is overlapped with the tail of the machine to realize material transfer. According to the force analysis during the movement of the lap joint trolley, the tail frame of the machine is optimized to form the optimal design parameters.