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Characterization of a Novel Mesophilic Bacterial Amylase Secreted by ZW2531-1, a Strain Newly Isolated from Soil

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Chemical Research in Chinese Universities 2009年第2期25卷 198-202页

作者： WANG yang li fan GAO Chao-hui ZHANG Ying-Jiu Key Laboratory for Molecular Enzymology and Engineering of Ministry of Education Jilin University Changchun 130021 P. R. China

A novel mesophilic bacterial amylase, named oligosaccharide-producing multifunctional amylase（OPMA）, was discovered and characterized. OPMA is an extracellular enzyme secreted by ZW253 1-1, a strain newly isolated from Chinese soil. It could be purified to homogeneity from the culture supernatant of ZW2531-1 by 30%-60% saturated ammonium sulfate precipitation, followed by twice Sephadex gel filtration chromatography. OPMA is a 66 kDa protein based on SDS-PAGE and has an isoelectric point（p/） at pH=5.3 by Isoelectric focusing electrophoresis（WE）. It only catalyzes the degradation of starch, rather than other alpha-l,4- and/or 1,6-glucan polysaccbarides such as fl-cyclomaltodextrin and pullulan. OPMA degraded starch to produce several oligosccharides including maltose, maltotriose, and isomaltotriose as the major end-products, and perhaps other oligosaccharides such as isomalto- tetraose, rather than glucose. OPMA exhibited optimal catalytic activity at a reaction temperature of 50 ℃ and pH=6.0, as determined by orthogonal test. Under the optimal reaction conditions, purified OPMA bad a specific activity of 13.75 U/rag. These findings suggest that OPMA could be used for the production of some oligosaccharides beneficial to the food industry and medicine.

关键词： Amylase Bacterium Oligosaccharide Purification Starch

Evolution of inner wall wrinkle defects in the sinking zone of a thick-walled steel tube during radial forging

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Advances in Manufacturing 2024年第2期12卷 396-408页

作者： Yu-Zhao yang Cheng Xu li-Xia fan School of Mechanical Engineering Nanjing University of Science and TechnologyNanjing210094People’s Republic of China

An axial wrinkle defect was observed in the inner wall of the sinking zone of a thick-wall steel tube processed by cold radial *** can evolve into *** present study focuses on the evolution of wrinkles and the effects of process parameters on them using a three-dimensional radial forging process finite element model,radial forging experiments,and surface morphology *** results indicated that the vertical section angle of the hammer die and the size of the tube blank significantly affect the evolution of *** height-to-width ratioλwas introduced to describe the morphology of *** had an approximately linear relationship with the radius reduction in the sinking *** was a linear correlation between the growth slope ofλand the axial to circumferential strain ratio|εr/εθ|,which can predict theλunder few process *** the 30SiMn2MoVA steel,at the junction of the forging and sinking zones,the threshold ofλof the wrinkle that can evolve into a fissure is approximately 1.123.

关键词： Radial forging Inner wall Wrinkle defects Evolution Sinking zone

Tolerability and toxicity of adjuvant cisplatin and gemcitabine for treating non-small cell lung cancer

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Chinese Medical Journal 2013年第11期126卷 2087-2091页

作者： yang fan li Xiao CHEN Ke-zhong JIANG Guan-chao WANG Jun Department of Thoracic Surgery Peking University Peoples'Hospital Beijing 100044 China

Background The combination of cisplatin and vinorelbine is an evidence-supported regimen for adjuvant chemotherapy for treating non-small cell lung cancer （NSCLC）. But this doublet has considerable toxicity and unfavorable tolerability, and results in poor compliance. The cisplatin and gemcitabine regimen is one of the most active and well-tolerated regimens against advanced NSCLC, but its toxicity and tolerability has not been adequately evaluated in the adjuvant setting. Methods From a lung cancer database we retrospectively reviewed NSCLC patients receiving adjuvant chemotherapy of cisplatin （75 mg/m2） and gemcitabine （1250 mg/m2） between January 2005 and December 2011. Postoperative demographics, compliance to adjuvant therapy and toxicity were retrieved from medical records. Results A total of 132 patients met the criteria and were included in the study, 96 were male （72.7%） and 36 were female （27.3%）. Median age was 60.5 years old, range 29-75 years, and 41.7% of patients were 〉65 years old. Overall, 68.2% patients received all four planned cycles, and the cumulative dose delivered for gemcitabine was 8333 mg （83.3% of the planned dose） and cisplatin 248 mg （82.7% of the planned dose）. There were no treatment-related deaths. Grade 3/4 neutropenia developed in 47 patients （35.6%） and was the predominant hematologic toxicity. Common grade 3/4 non- hematologic toxicities were nausea/vomiting （22.0%）, infection （12.3%）, and febrile neutropenia （11.4%）. Conclusion Cisplatin and gemcitabine are feasible for use in the adjuvant setting with a favorable toxicity profile and superior tolerabilitv compared with Dublished data on cisDlatin and vinorelbine.

关键词： non-small cell lung cancer adjuvant drug therapy toxicity tolerability

WEAK-STRONG UNIQUENESS FOR THREE DIMENSIONAL INCOMPRESSIBLE ACTIVE liQUID CRYSTALS

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Acta Mathematica Scientia 2024年第4期44卷 1415-1440页

作者： fan yang Congming li School of Mathematical Sciences CMA-ShanghaiShanghai Jiao Tong UniversityShanghai 200240China

The hydrodynamics of active liquid crystal models has attracted much attention in recent years due to many applications of these *** this paper,we study the weak-strong uniqueness for the Leray-Hopf type weak solutions to the incompressible active liquid crystals in R^(3).Our results yield that if there exists a strong solution,then it is unique among the Leray-Hopf type weak solutions associated with the same initial data.

关键词： analysis of parabolic and elliptic types weak-strong uniqueness active liquid crystals weak solution energy equality

A muon high-resolution pseudorange measurement method: Application to muon navigation in confined spaces

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Chinese Journal of Aeronautics 2024年第4期37卷 391-404页

作者： Haoyang li Chunxi ZHANG Xingming fan Longjie TIAN Tianqi li yang PANG Yanqiang yang Institute of Optics and Electronics School of Instrumentation Science and Optoelectronics EngineeringBeihang UniversityBeijing 100191China Institute of High Energy Physics Chinese Academy of SciencesBeijing 100049China

Confined spaces such as polar regions, deep earth and deep ocean are crucial navigation scenarios where traditional navigation techniques have difficulty in obtaining external signals for positioning. The cosmic ray muons, which carry the spatial and energetic information, are easy to penetrate these confined spaces. Therefore, the unique muon characteristic provides a new perspective to estimate detector position, which can be considered using in confined spaces *** this paper, a well-developed theory of muon navigation is established by combining a muon pseudorange measurement method. Moreover, an Equivalent Velocity Calculation Model(EVCM)and a Muon Sequence Matching Technology(MSMT) are proposed. The first model corrects flight pseudorange error caused by the relativistic energy loss and the second technology compensates the random error in pseudorange measurement. Further, a series of simulations are performed to analyze the muon events number which can be received by detector in different scenarios with the variations of zenith angle, detector area, varied detector plates gap, and muon flight ***, the simulation results demonstrate that the muon navigation update rate every 10 minutes can reach 5.989 in confined spaces at 100 m, and further pseudorange error analysis indicates that the meter-level positioning accuracy can be acquired. Finally, we construct a muon coincidence measurement scheme and verify that the laws of the muon positioning system for high-energy muons are consistent with the simulation results.

关键词： Muon navigation Cosmic ray muons Muon detection technology Muon transmission technology Pseudorange measurement

Energy mechanism of bolt supporting effect to fissured rock under static and dynamic loads in deep coal mines

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International Journal of Mining Science and Technology 2024年第3期34卷 371-384页

作者： Deyuan fan Xuesheng liu Yunliang Tan Xuebin li Shenglong yang College of Energy and Mining Engineering Shandong University of Science and TechnologyQingdao 266590China State Key Laboratory of Mining Disaster Prevention and Control Shandong University of Science and TechnologyQingdao 266590China National Energy Group Ningxia Coal Industry Co. Ltd.Yinchuan 753001China

The stability control of fissured rock is difficult,especially under static and dynamic loads in deep coal *** this paper,the dynamic mechanical properties,strain rate evolution and energy dissipation of fissured and anchored rocks were respectively obtained by SHPB *** was found that bolt can provide supporting efficiency-improving effect for fissured rock against dynamic disturbance,and this effect increased quadratically with decrease in anchoring ***,the energy dissipation mechanism of anchored rock was obtained by slipping ***,bolt energy-absorbing mechanism by instantaneous tensile-shear deformation was expressed based on material mechanics,which was the larger the anchoring angle,the smaller the energy absorption,and the less the contribution to supporting efficiency *** this basis,the functional relationship between energy dissipation of anchored rock and energy absorption of bolt was *** the coal-gangue separation system of Longgu coal mine as an example,the optimal anchoring angle can be determined as 57.5°–67.5°.Field monitoring showed fissured rock with the optimal anchoring angle,can not only effectively control the deformation,but also fully exert the energy-absorbing and efficiency-improving effect of bolt *** study provides guidance to the stability control and supporting design for deep engineering under the same or similar conditions.

关键词： Static and dynamic loads Anchored rock Energy absorption Anchoring angle Engineering verification

A multi-scale framework for life reduction assessment of turbine blade caused by microstructural degradation

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Chinese Journal of Aeronautics 2024年第1期37卷 186-200页

作者： Xiaoguang yang Menglei WANG Duoqi SHI Zhenlei li Yongsheng fan School of Energy and Power Engineering Beihang UniversityBeijing 102206China Research Institute of Aero-Engine Beihang UniversityBeijing 102206China National Key Laboratory of Science and Technology on Aero-Engine Aero-Thermodynamics Beihang UniversityBeijing 102206China

The prolonged thermal exposure with centrifugal load results in microstructural degradation,which ultimately leads to a reduction in the fatigue and creep resistance of the turbine *** present work proposes a multi-scale framework to estimate the life reduction of turbine blades,which combines a microstructural degradation model,a two-phase constitutive model,and a microstructure-dependent fatigue and creep life reduction *** framework with multi-scale models is validated by a Single Crystal(SC)Ni-based superalloy at the microstructural length-scale and is then applied to calculate the microstructural degradation and the fatigue and creep life reduction of turbine blades under two specific service *** simulation results and quantitative analysis show that the microstructural degradation and fatigue and creep life reduction of the turbine blade are heavily influenced by the variations in the proportion of the intermediate state,namely,the maximum rotor speed status,in the two specific service *** intermediate state accelerates the microstructural degradation and leads to a reduction of the life,especially the effective fatigue life reserve due to the higher temperature and rotational speed than that of the 93%maximum rotor speed status marked as the reference *** proposed multi-scale framework provides a capable approach to analyze the reduction of the fatigue and creep life for turbine blade induced by microstructural degradation,which can assist to determine a reasonable Time Between Overhaul(TBO)of the engine.

关键词： Creep Fatigue life reduction Microstructural degradation Multi-scale modeling Turbine blades

Data complexity-based batch sanitization method against poison in distributed learning

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Digital Communications and Networks 2024年第2期10卷 416-428页

作者： Silv Wang Kai fan Kuan Zhang Hui li Yintang yang State Key Laboratory of Integrated Service Networks Xidian UniversityXi'an710126China Department of Electrical and Computer Engineering University of Nebraska-LincolnLincolnNE68588USA Key Lab.of the Minist.of Educ.for Wide Bandgap Semiconductor Materials and Devices Xidian UniversityXi'an710071China

The security of Federated Learning(FL)/Distributed Machine Learning(DML)is gravely threatened by data poisoning attacks,which destroy the usability of the model by contaminating training samples,so such attacks are called causative availability indiscriminate *** the problem that existing data sanitization methods are hard to apply to real-time applications due to their tedious process and heavy computations,we propose a new supervised batch detection method for poison,which can fleetly sanitize the training dataset before the local model *** design a training dataset generation method that helps to enhance accuracy and uses data complexity features to train a detection model,which will be used in an efficient batch hierarchical detection *** model stockpiles knowledge about poison,which can be expanded by retraining to adapt to new *** neither attack-specific nor scenario-specific,our method is applicable to FL/DML or other online or offline scenarios.

关键词： Distributed machine learning security Federated learning Data poisoning attacks Data sanitization Batch detection Data complexity

Cooperative decision-making algorithm with efficient convergence for UCAV formation in beyond-visual-range air combat based on multi-agent reinforcement learning

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Chinese Journal of Aeronautics 2024年第8期37卷 311-328页

作者： Yaoming ZHOU fan yang Chaoyue ZHANG Shida li Yongchao WANG School of Aeronautic Science and Engineering Beihang UniversityBeijing 100191China Key Laboratory of Industrial Control Technology Institute of Cyber-Systems and ControlZhejiang UniversityHangzhou 310027China

Highly intelligent Unmanned Combat Aerial Vehicle(UCAV)formation is expected to bring out strengths in Beyond-Visual-Range(BVR)air *** Multi-Agent Reinforcement Learning(MARL)shows outstanding performance in cooperative decision-making,it is challenging for existing MARL algorithms to quickly converge to an optimal strategy for UCAV formation in BVR air combat where confrontation is complicated and reward is extremely sparse and *** to solve this problem,this paper proposes an Advantage Highlight Multi-Agent Proximal Policy Optimization(AHMAPPO)***,at every step,the AHMAPPO records the degree to which the best formation exceeds the average of formations in parallel environments and carries out additional advantage sampling according to ***,the sampling result is introduced into the updating process of the actor network to improve its optimization ***,the simulation results reveal that compared with some state-of-the-art MARL algorithms,the AHMAPPO can obtain a more excellent strategy utilizing fewer sample episodes in the UCAV formation BVR air combat simulation environment built in this paper,which can reflect the critical features of BVR air *** AHMAPPO can significantly increase the convergence efficiency of the strategy for UCAV formation in BVR air combat,with a maximum increase of 81.5%relative to other algorithms.

关键词： Unmanned combat aerial vehicle(UCAV)formation Decision-making Beyond-visual-range(BVR)air combat Advantage highlight Multi-agent reinforcement learning(MARL)