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Influence of the upstream axial magnetic mirror field on the plume characteristics in the full cylindrical Hall thruster

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ACTA ASTRONAUTICA 2022年 196卷 186-193页

作者： gao, Yuanyuan Wang, Weizong Xue, shuwen Li, Yifei Cai, Guobiao Beihang Univ Sch Astronaut Adv Space Prop & Energy Lab ASPEL Beijing 100191 Peoples R China Beihang Univ Ningbo Inst Technol Aircraft & Prop Lab Ningbo 315832 Peoples R China

Full cylindrical Hall thruster holds considerable promise in terms of its low wall erosion rate and long-lifetime performance advantages. As far as we know, its upstream magnetic mirror field plays a fundamental role in the determination of plasma behavior and hence the thruster performance. In this paper, a series of upstream axial magnetic mirror fields with different axial gradient values were generated by adjusting the inverse-electromagnetic coil currents near the upstream channel and its effect on the plume characteristics were investigated. The experiment results indicate that under a low magnetic mirror field with 44.8 G/mm gradient value, a bulb-like plasma discharge region emitting a visible high-intensity light is discovered near the thruster exhaust, its plume manifests a hollow profile with a plume angle of 77 degrees. In contrast, as the axial gradient value of magnetic mirror field increases from 44.8 G/mm to 72.5 G/mm, this bulb-like plasma region near exhaust shrink gradually to disappear along with the plume angle decreasing to 65 degrees. Meanwhile, the anode efficiency enhances significantly (from 16% to 28%) correspondingly. According to the analysis of ion current, electron current and ion energy distribution, the observed strong plasma discharge near the thruster exhaust should be intimately related with the extension of the ionization region towards exit due to the weak electron confinement under the low magnetic mirror field. However, the larger upstream magnetic mirror field could diminish the leaking of local electrons towards the anode efficiently, which could not only intensify the ionization, but also induce the shrink of the ionization region axially towards the upstream channel and the clearer separation of acceleration region from the ionization region. Ultimately, the enhanced propellant utilization and current utilization, higher ion energy and the collimated plume are achieved. This work provides a feasible way to recognize the io

关键词： Full cylindrical Hall thruster Magnetic mirror field Plume characteristics

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The effect of Maillard reaction on flavour development of protein hydrolysates from cheese

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FOOD CHEMISTRY 2024年第Part1期437卷 137569页

作者： gao, Peng Zhang, Wenyuan Zhao, Xiaoxuan Xu, Chen Pang, Xiaoyang Fauconnier, Marie-Laure Zhang, shuwen Lv, Jiaping Chinese Acad Agr Sci Inst Food Sci & Technol Beijing 100193 Peoples R China Univ Liege Lab Chim Mol Nat LCMN Gembloux Agro Bio Tech 2 Passage Deportes B-5030 Gembloux Belgium Wageningen Univ & Res Food Qual & Design Grp Dairy Sci & Technol Wageningen Netherlands Chinese Acad Agr Sci Inst Anim Sci 2 Yuan Ming Yuan West Rd Beijing 100193 Peoples R China

This study aims to explore the effect of the Maillard reaction (MR) on flavour development of cheese protein hydrolysates. In addition, the effects of proteolysis, lipolysis, and the degreasing process on the MR have been explored. Cheese protein hydrolysates subjected to different treatments were heated with glucose and xylose, and their amino reactant components, colour parameters, and volatile compounds were determined. The results showed that the MR significantly affected the content of free amino acids, peptides, and volatile flavours of cheese protein hydrolysates. Peptides below 1500 Da and most of the free amino acids were the important amino reactants during the MR. 3-Ethyl-2,5-dimethylpyrazine, 2,5-dimethylpyrazine, 2-undecanone and 2-heptanone were the key volatile components of the MR products. The results also indicated that N-terminal amino acids of the peptide chain were easier to be reacted than C-terminal amino acids and thus produce a pyrazine-like flavour in the MR.

关键词： Maillard reaction Flavour development Degrease Lipolysis Peptidomics

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Hydrogel-Coated Microelectrode Resists Protein Passivation of In Vivo Amperometric Sensors

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ANALYTICAL CHEMISTRY 2023年第6期95卷 3390-3397页

作者： Yin, Yongyue Zeng, Hui Zhang, Shuai gao, Nan Liu, Rantong Cheng, shuwen Zhang, Meining Renmin Univ China Dept Chem Beijing 100872 Peoples R China

Passivation of electrodes caused by nonspecific adsorption of protein can dramatically reduce sensing sensitivity and accuracy, which is a great challenge for in vivo neurochemical monitoring. However, most antipassivation strategies are not suitable to carbon fiber microelectrodes (CFMEs) for in vivo measurement, and these methods also do not work on electrochemical biosensors that fix biometric elements. In this study, we demonstrate that chitosan hydrogel-coated microelectrodes can avoid the current passivation caused by protein adsorption on the surface of carbon fiber because the chitosan hydrogel prepared by local pH gradient caused by hydrogen evolution reaction has three-dimensional networks containing large amounts of water. The highly hydrophilic three-dimensional structure of hydrogel not only forms a biocompatible interface to confine enzymes but also keeps the fast mass transfer of analytes, such as dopamine, ascorbic acid, and glucose. The consistency of the precalibration and postcalibration of the prepared sensor enables in vivo amperometric detection of both electroactive species based on their redox property and electroinactive species based on the enzyme. This study provides a simple and versatile strategy to constitute an amperometric sensor interface to resist passivation of protein adsorption in a complex biological environment such as the brain.

关键词： Amperometry

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The optimal dosage of aspirin for preventing preeclampsia in high-risk pregnant women: A network meta-analysis of 23 randomized controlled trials

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JOURNAL OF CLINICAL HYPERTENSION 2024年第5期26卷 455-464页

作者： Hu, Xuemei Chen, Dexin Wang, Hong Lv, Yinfeng Wang, Yulong gao, Xuelin Li, shuwen He, Rongxia Lanzhou Univ Hosp 2 Dept Obstet 82 Cuiying Gate Lanzhou Gansu Peoples R China

This study aimed to assess the effectiveness and optimal dosage of aspirin in preventing preeclampsia in high-risk pregnant women. Traditional and network meta-analyses were conducted on data from 23 randomized controlled trials involving 10 547 pregnant women. The findings demonstrated that aspirin significantly reduced the incidence of preeclampsia (OR = 0.66, 95%CI [0.58, 0.75]), with the best preventive effect observed at a dosage of 80-100 mg/day (OR = 0.51, 95%CI [0.36, 0.72]). No significant differences were found in the occurrence of postpartum hemorrhage (OR = 1.03, 95%CI [0.79, 1.33]), small for gestational age (OR = 0.83, 95%CI [0.50, 1.35]), placental abruption (OR = 0.96, 95%CI [0.53, 1.73]), and intrauterine growth restriction (OR = 0.63, 95%CI [0.45, 1.86]) between women taking aspirin and those taking placebos. Different doses of aspirin showed a reduction in preeclampsia incidence, but there was no significant difference in efficacy between the dosage groups. Side effects did not significantly differ between placebo and different aspirin dosage groups. SUCRA analysis suggested that 80-100 mg/day may be the optimal dosage, prioritizing both effectiveness and minimizing side effects. Sensitivity analysis confirmed the robustness of the findings. However, improvements are needed in addressing issues like loss to follow-up, reporting bias, and publication bias. In conclusion, a dosage of 80-100 mg/day is recommended for preventing preeclampsia in high-risk pregnant women, although individual circumstances should be considered for optimizing the balance between effectiveness and safety.

关键词： aspirin high-risk network meta-analysis optimal dosage preeclampsia

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Optimization of Ball Valve Housing Based on Xgboost Regression Model 21

Optimization of Ball Valve Housing Based on Xgboost Regressi...

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21st International Computer Conference on Wavelet Active Media Technology and Information Processing, ICCWAMTIP 2024

作者： Wenyi, Xu Jiawei, Dai Shun, gao Xiaoqin, Liang shuwen, Wang School of Mechanical and Electrical Engineering University of Electronic Science and Technology of China Chengdu China

ISBN: (纸本)9798331519254

Ball valves play a pivotal role in industrial piping systems, with their design directly influencing system safety, stability, and fluid control efficiency. The thickness of the shell is a crucial parameter for ensuring structural strength and safety. Traditionally, this parameter has been determined using empirical formulas or standard specifications based on nominal pressure, diameter, and material properties. However, these methods are based on idealized assumptions that do not account for complex working conditions such as high pressure and temperature. This can result in reduced accuracy and potential safety risks. To address this issue, this study employs the Extreme Gradient Boosting (XGBoost) regression algorithm, utilizing historical data to train a machine learning model for precise ball valve design predictions. © 2024 IEEE.

关键词： Safety valves

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CIAO: Cache Interference-Aware Throughput-Oriented Architecture and Scheduling for GPUs 32

CIAO: Cache Interference-Aware Throughput-Oriented Architect...

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32nd IEEE International Parallel and Distributed Processing Symposium (IPDPS)

作者： Zhang, Jie gao, shuwen Kim, Nam Sung Jung, Myoungsoo Yonsei Univ Sch Integrated Technol Seoul South Korea Intel Santa Clara CA USA Univ Illinois Champaign IL USA

ISBN: (纸本)9781538643686

A modern GPU aims to simultaneously execute more warps for higher Thread-Level Parallelism (TLP) and performance. When generating many memory requests, however, warps contend for limited cache space and thrash cache, which in turn severely degrades performance. To reduce such cache thrashing, we may adopt cache locality-aware warp scheduling which gives higher execution priority to warps with higher potential of data locality. However, we observe that warps with high potential of data locality often incurs far more cache thrashing or interference than warps with low potential of data locality. Consequently, cache locality-aware warp scheduling may undesirably increase cache interference and/ or unnecessarily decrease TLP. In this paper, we propose Cache Interference-Aware throughput-Oriented (CIAO) on-chip memory architecture and warp scheduling which exploit unused shared memory space and take insight opposite to cache locality-aware warp scheduling. Specifically, CIAO on-chip memory architecture can adaptively redirect memory requests of severely interfering warps to unused shared memory space to isolate memory requests of these interfering warps from those of interfered warps. If these interfering warps still incur severe cache interference, CIAO warp scheduling then begins to selectively throttle execution of these interfering warps. Our experiment shows that CIAO can offer 54% higher performance than prior cache locality-aware scheduling at a small chip cost.

关键词： GPGPU thread-level parallelism warp scheduling interference

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Understanding the evolution of mining-induced fractures using physical and numerical modeling

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ENVIRONMENTAL EARTH SCIENCES 2022年第1期81卷 22页

作者： gao, Fuqiang Li, Jianzhong Lou, Jinfu Cao, shuwen Liu, Xiaomin China Coal Res Inst State Key Lab Coal Min & Clean Utilizat Beijing Peoples R China CCTEG Coal Min Res Inst Beijing Peoples R China

The overburden rock strata fractures and collapses as the extraction of a longwall panel. Knowledge of the extents and characteristics of the fractured zone is important to evaluating many mining-induced issues including abutment pressure relief, methane production, and ground subsidence prediction. In this study, a physical model was initially created to produce the process of longwall mining with great attention focused on the caving and fracturing process of the overburden strata. A numerical model was then created according to the geological and geotechnical conditions of the physical model. Both the physical and numerical model successfully captured periodic weighting as the longwall face advances. It is found that periodic weighting does not just involve the local immediate and main roof that composes a cantilever beam right behind the longwall face, it may also involve the rupture of a rock bridge in the overburden strata above the fractured zone. The rock bridge forms and ruptures periodically as longwall mining proceeds. The permeability of a given region in the fractured zone can be evaluated by measuring the area of the voids and fractures within the region. The permeability increases as fracturing and collapse of rock mass within the region and then decreases as the collapsed rock mass compacts. The greater the horizontal-to-vertical stress ratio, the lower the maximum permeability. The more competent the main roof, the lower the maximum permeability.

关键词： Mining-induced fractures Permeability Roof bridge Physical model Numerical model

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Dandelion-like nickel/cobalt metal-organic framework based electrode materials for high performance supercapacitors

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JOURNAL OF COLLOID AND INTERFACE SCIENCE 2018年 531卷 83-90页

作者： gao, shuwen Sui, Yanwei Wei, Fuxiang Qi, Jiqiu Meng, Qingkun Ren, Yaojian He, Yezeng China Univ Min & Technol Sch Mat Sci & Engn Xuzhou 221116 Jiangsu Peoples R China

Metal-organic frameworks (MOFs), serving as a promising electrode material in the supercapacitors, have attracted tremendous interests in recent years. Here, through modifying the molar ratio of the Ni2+ and Co2+, we have successfully fabricated Ni-MOF and Ni/Co-MOF by a facile hydrothermal method. The Ni/Co-MOF with a dandelion-like hollow structure shows an excellent specific capacitance of 758 F g(-1) at 1 A g(-1) in the three-electrode system. Comparing with Ni-MOF, the obtained Ni/Co-MOF has a better rate capacitance (89% retention at 10 A g(-1)) and cycling life (75% retention after 5000 circulations). Besides, the assembled asymmetric supercapacitor based on Ni/Co-MOF and active carbon exhibits a high specific energy density of 20.9 W h kg(-1) at the power density of 800 W kg(-1). All these results demonstrate that the mixed-metal strategy is an effective way to optimize the morphology and improve the electrochemical property of the MOFs. (C) 2018 Elsevier Inc. All rights reserved.

关键词： Ni-MOF Ni/Co-MOF Supercapacitors

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Fatty acid and triglyceride molecular species of milk fat fractionated by short-path molecular distillation

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INTERNATIONAL JOURNAL OF FOOD SCIENCE AND TECHNOLOGY 2023年第7期58卷 3742-3751页

作者： Zhu, Huiquan Wang, Xiaodan Zhang, Wenyuan Zhang, Yumeng gao, Xixi Wang, Yunna gao, Peng Pang, Xiaoyang Zhang, shuwen Lv, Jiaping Chinese Acad Agr Sci Inst Food Sci & Technol Beijing 100193 Peoples R China Univ Liege Lab Chem Nat Mol Gembloux Agrobio Tech B-5030 Gembloux Belgium Wageningen Univ & Res Dept Anim Sci Adaptat Physiol Grp Wageningen Netherlands Wageningen Univ & Res Lab Biochem Wageningen Netherlands

Fractionation is important for the application of milk fat (MF). In this study, the contents of fatty acid (FA) and triglyceride (TAG) of MF and its fractions distilled by short-path molecular distillation (SPMD) were detected. The results showed that a total of 19 FAs and 109 TAG molecular species were detected. Moreover, the short-chain saturated FA, medium-chain saturated FA, low-molecular-weight TAG, medium-molecular-weight TAG, S-3 (TAG molecular species with three saturated FAs) and L2S (TAG molecular species with two long-chain FAs and one short-chain FA) were easily accumulated in the distillate, and the percentage of these components all increased first and then decreased during the whole distilling process. Compared with the distillate, polyunsaturated FA (PUFA) and high-molecular-weight TAG (HMW-TAG, with the carbon numbers: 41-54 and molecular weight: 704-888) were enriched in the residue, and the increasing ratio of PUFA and HMW-TAG was 393.75% and 8.58% respectively. Further analysis showed that the 16:0/4:0/16:0, 16:0/4:0/14:0, 16:0/12:0/4:0, etc. were the discrepant TAG molecular species during SPMD. Therefore, these results demonstrated that different fractions of MF could be obtained by adjusting the fractionation temperature, and it also would provide more important theoretical guidance for regulating MF fractionation, enriching the nutritional information of MF fractions.

关键词： Fatty acid Molecular species Short-path molecular distillation Triglyceride

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Enhancement of visible-light-driven oxidative amine coupling under aerobic and anaerobic conditions by photocatalyst with spatial separation of photoinduced charge carriers

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Nano Research 2023年第4期16卷 4715-4722页

作者： Shasha Wang Kuan gao Yang Cui shuwen Li Heyao Zhang Bin Zhang Jie Wu Hongwei Hou Shuangquan Zang Green Catalysis Center College of ChemistryZhengzhou UniversityZhengzhou 450001China School of Chemical Engineering Zhengzhou UniversityZhengzhou 450001China School of Science Xuchang UniversityXuchang 461000China

Spatial separation of oxidation/reduction cocatalyst is an effective means to improve the efficiency of charge separation in photocatalytic reaction ***,a yolk-shell Pd@NH_(2)-UiO-66@Cu_(2)O heterojunction was designed and synthesized by integration of electron collector Pd and hole collector Cu_(2)O inside and outside of a photoactive metal-organic framework(MOF)NH_(2)-UiO-66,*** obtained Pd@NH_(2)-UiO-66@Cu_(2)O heterojunction effectively inhibits the electron and hole recombination through the photo-induced electrons and holes flow inward and outward of the composite,and promotes the reduction and oxidation abilities for the oxidative coupling of benzylamine to *** with Pd/NH_(2)-UiO-66@Cu_(2)O,Pd@NH_(2)-UiO-66,and Pd/NH_(2)-UiO-66,Pd@NH_(2)-UiO-66@Cu_(2)O exhibits the highest photocatalytic *** importantly,Pd@NH_(2)-UiO-66@Cu_(2)O shows a conversion rate of benzylamine up to 99%either by oxidation under aerobic conditions or by strong adsorption of H atom(Hads)under anaerobic *** addition,the catalyst shows good stability and can be recycled at least ten *** work provides useful guidance on construction of MOFs-based composites with spatially separated photoinduced charge carriers to realize efficient oxidation coupling of benzylamine in both aerobic and anaerobic conditions.

关键词： metal-organic frameworks palladium nanoparticle photocatalysis cuprous oxide oxidative coupling of amines

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