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An optimization method for passive muzzle arc control devices in augmented railguns

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Defence Technology（防务技术） 2022年第2期18卷 271-279页

作者： Bo Tang Qing-hua lin Bao-ming li National Key Laboratory of Transient Physics Nanjing University of Science and TechnologyNanjing210094JiangsuChina China Academy of Ordnance 100089BeijingChina

In this paper,a passive muzzle arc control device(PMACD)of the augmented railguns is studied.By discussing its performance at different numbers of extra rails,a parameter optimization model is proposed.Through the calculation model,it is found that the PMACD works well in the simple railgun,which refers to the gun that there is only one pair of rails in the inner bore.The PMACD may decrease the simple railgun’s armature peak current and muzzle arc,but affect its muzzle velocity not much.However,in the augmented railguns it has different characteristics.If the parameters of the PMACD are not selected suitable.It may increase the armature peak current and muzzle arc,but greatly decrease the velocity.The reason for this problem is that the extra rails generate a strong magnetic field in front of the armature,which induces a large current to change the armature current.It is also found that when the resistance and inductance parameters of the PMACD satisfy with the optimization formula,the PMACD can also play a good role in arc suppression in the augmented railguns.Experiments of an augmented railgun with a stainless steel PMACD are carried out to verify this optimization method.Results show that the muzzle arc is obviously controlled.This work may provide a reference for the design of the muzzle arc control device.

关键词： Augmented railguns Arc suppression Muzzle device Optimization method Shunts

Self-assembled Conformations of a Core-shell Comb-like Chain with Adjustable Architectural Parameters

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Chinese Journal of Polymer Science 2023年第9期41卷 1439-1446,I0008页

作者： huan-li Qi Heng-Wei Zhou Chao Duan Wei-hua li ming-ming Ding Xinjiang Laboratory of Phase Transitions and Microstructures in Condensed Matter Physics College of Physical Science and TechnologyYili Normal UniversityYining835000China State Key Laboratory of Molecular Engineering of Polymers Department of Macromolecular ScienceFudan UniversityShanghai200433China School of Chemical Engineering and light Industry Guangdong University of TechnologyGuangzhou510006China

Combining Brownian dynamics simulations and self-consistent field theory,we demonstrate that the architectural parameters of coreshell comb-like chains have a decisive influence on their final self-assembled conformations.When the ratio of hydrophilic and hydrophobic segments is N_(g,g)∶N_(g,r)=3∶1,no core-shell structure is observed,and unsegregated chains or clusters are substituted.When N_(g,g)∶N_(g,r)=3∶2or 3∶3,the core-shell comb-like chains can be assembled into single micelles or structures where several small micelles are strung together by the backbone,which is similar to the pearl-necklace structure formed by the polyelectrolytes in poor solvent.With the increase of backbone length or grafting density,the probability of forming single micelles becomes lower,but the structures of two,three or more small micelles strung together are more observed.Our results indicate how to obtain the desired self-assembled structures of core-shell comb-like chains by regulating the architectural parameters,which could provide insights for the optimization of molecular design in various applications.

关键词： Comb-like polymer Self-assembled conformations Brownian dynamics simulations

Instability of solution-processed perovskite films:origin and mitigation strategies

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Materials Futures 2023年第1期2卷 26-59页

作者： Shuo Wang ming-hua li Yan Jiang Jin-Song Hu Beijing National Laboratory for Molecular Sciences(BNLMS) Institute of ChemistryChinese Academy of SciencesBeijing 100190People’s Republic of China School of Materials Science and Engineering Beijing Institute of TechnologyBeijing 100081People’s Republic of China University of Chinese Academy of Sciences Beijing 100049People’s Republic of China

Perovskite solar cells(PSCs)are promising next-generation photovoltaics due to their unique optoelectronic properties and rapid rise in power conversion efficiency.However,the instability of perovskite materials and devices is a serious obstacle hindering technology commercialization.The quality of perovskite films,which is an important prerequisite for long-term stable PSCs,is determined by the quality of the precursor solution and the post-deposition treatment performed after perovskite formation.Herein,we review the origin of instability of solution-processed PSCs from the perspectives of the precursor solutions and the perovskite films.In addition,we summarize the recent strategies for improving the stability of the perovskite films.Finally,we pinpoint possible approaches to further advance their long-term stability.

关键词： stability perovskite solar cells precursor solution perovskite films degradation

Study on Evaluation Method of Failure Pressure for Pipeline with Axially Adjacent Defects

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中国海洋工程:英文版 2023年第4期37卷 598-612页

作者： SUN ming-ming FANG Hong-yuan DU Xue-ming WANG Wen-hua li Xin School of Water Conservancy and Transportation Zhengzhou UniversityZhengzhou 450001China National Local Joint Engineering Laboratory of Major Infrastructure Testing and Rehabilitation Technology Zhengzhou 450001China Collaborative Innovation Center of Water Conservancy and Transportation Infrastructure Safety Zhengzhou 450001China Yellow River Laboratory Zhengzhou UniversityZhengzhou 450001China State Key Laboratory of Coastal and Offshore Engineering Dalian University of TechnologyDalian 116024China School of Hydraulic Engineering Faculty of Infrastructure EngineeringDalian University of TechnologyDalian 116024China

The interaction between axially adjacent defects is more significant than that between circumferentially aligned defects.However,the existing failure pressure assessment methods cannot accurately predict the failure pressure of axial adjacent defects.In the paper,the finite element model is adopted to analyze the influence of defect size,distribution mode and spacing between adjacent defects on failure pressure.A new failure pressure evaluation method is proposed by establishing the effective depth calculation model of corrosion colony with different distribution model.The burst test of X52 pipeline is carried out to verify the applicability of the method.It shows that the results of new method are consistent with the test results of pipeline with various defects and steel grades.

关键词： steel pipeline effective depth axially adjacent defects burst test evaluation method

Primary Systemic Amyloidosis Presenting as Skin Vegetations:A Case Report

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International Journal of Dermatology and Venereology 2022年第3期5卷 178-180页

作者： Meng-hua li li-ming Wu Department of Dermatology Affiliated Hangzhou First People’s HospitalZhejiang University School of MedicineHangzhouZhejiang 310006China

Introduction:Primary systemic amyloidosis is characterized by clonal plasma cell disorder,and its signs and symptoms are various and complex,damage to the skin and mucous membrane is often more likely to attract attention.Here we reported a case of a 61-year-old male patient who presented with topical mucocutaneous lesion,as well unusual skin vegetations.Case presentation:A 61-year-old man was hospitalized due to repeated burning sensation on his back,multiple ecchymosis,and skin vegetations.Through a series of examinations(mainly including skin histopathology,bone marrow cytology,bone marrow flow cytometry,immunofixation electrophoresis),Primary systemic amyloidosis was diagnosed,but multiple myeloma could not be diagnosed.Subsequently,he received chemotherapy.In the half-year follow-up,there was no significant change in his symptoms and signs.Discussion:In this case,in addition to the typical skin damage of primary amyloidosis,the multiple skin vegetations in the buttocks,abdomen,and arms are particularly noteworthy.According to the histopathology and Immunohistochemistry of the skin vegetation,we infer that the formation mechanism of these skin vegetation is lymphatic obstruction caused by amyloid,which leads to lymphatic dilatation,lymph leakage,and dermal edema.Conclusion:Primary systemic amyloidosis is a rare disease,which is often difficult to diagnose.We should be alert to those atypical skin features so as not to delay diagnosis.

关键词： primary systemic amyloidosis skin vegetations case report

Advantage in Bright-blood and Black-blood Magnetic Resonance Imaging with High-resolution for Analysis of Carotid Atherosclerotic Plaques

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Chinese Medical Journal 2015年第18期128卷 2478-2484页

作者： Mei li Wei-Jie Le Xiao-Feng Tao ming-hua li Yue-hua li Nan Qu Department of Radiology Shanghai Sixth People's Hospital Affiliated to Shanghai Jiao Tong University Shanghai 200233 China Department of Radiology Shanghai Ninth People's Hospital Shanghai Jiao Tong University School of Medicine Shanghai 200011 China

Background： About 50% of the cerebral ischemia events are induced by intracranial and extracranial atheroscterosis. This study aimed to evaluate the feasibility and accuracy for displaying atherosclerotic plaques in carotid arteries and analyzing their ingredients by using high-resolution new magnetic resonance imaging （MRI） techniques. Methods： Totally, 49 patients suspected ofextracranial carotid artery stenosis were subjected to cranial MRI scan and magnetic resonance angiography （MRA） examination on carotid arteries, and high-resolution bright-blood and black-blood MRI analysis was carried out within 1 week. Digital subtraction angiography （DSA） examination was carried out for 16 patients within I month. Results： Totally, 103 plaques were detected in the 49 patients, which were characterized by localized or diffusive thickening of the vessel wall, with the intrusion of crescent-shaped abnormal signal into lumens. Fibrous cap was displayed as isointensity in T I -weighted image （T I WI） and hyperintensities in proton density weighted image （PDWI） and T2-weighted image （T2WI）, lipid core was displayed as isointensity or slight hyperintensities in T1WI, isointensity, hyperintensities or hypointensity in PDWI, and hypointensity in T2WI. Calcification in plaques was detected in 11 patients. Eight patients were detected with irregular plaque surface or ulcerative plaques, which were characterized by irregular intravascular space surface in the black-blood sequences, black hypointensity band was not detected in three-dimensional time-of-flight, or the hypointensity band was not continuous, and intrusion of hyperintensities into plaques can be detected. Bright-blood and black-blood techniques were highly correlated with the diagnosis of contrast-enhanced MRA in angiostenosis degree, Rs 0.97, P 〈 0.001. In comparison to DSA, the sensitivity, specificity, and accuracy of MRI diagnosis of stenosis for ≥50% were 88.9%. 100%, and 97.9%, respectively. Conclusions： High-resolution bright-blood and black-blood sequential MRI

关键词： Atherosclcrosis Black-blood Bright-blood Carotid Arteries Magnetic Resonance Image

Numerical simulation of dynamic large deformation and fracture damage for solid armature in electromagnetic railgun

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Defence Technology（防务技术） 2020年第2期16卷 348-353页

作者： Qing-hua lin Bao-ming li National Key Laboratory of Transient Physics Nanjing University of Science and TechnologyP.O.Box210094NanjingPR China

The design of solid armature of railgun should take full account of its operating conditions and material properties because the armature is subjected to dynamic loading conditions and experiences a complicated electrical,thermal and mechanical process in the interior ballistic cycle.In this paper present,we first introduced a multi-physical field model of railgun,followed by several examples to investigate the launching process.Especially,we used the explicit finite element method,in which material nonlinearity and geometric nonlinearity were accounted,to investigate the deform behaviors of solid armature.The results show that the dynamic mechanical process of armature is dependent on the armature geometry,material and exciting electric current.By the numerical simulation,the understanding of the fracture mechanism of solid armature was deepened.

关键词： Electromagnetic railgun Solid armature Fracture Explicit finite element Numerical simulation

The Immune Responses Induced by licensed Flavivirus Vaccines against Zika Virus

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Biomedical and Environmental Sciences 2022年第8期35卷 750-754页

作者： WANG ling liU Jing Jing FANG En Yue li ming liU ming Lei li Yu hua State Key Laboratory of Biotherapy and Cancer Center West China HospitalSichuan Universityand Collaborative Innovation Center for BiotherapyChengdu 610041SichuanChina National Institutes for Food and Drug Control Beijing 102629China

Zika virus(ZIKV) is a mosquito-borne virus of the Spondweni group that belongs to the Flaviviridae family and genus Flavivirus. Microcephaly(small head size, decreased brain size, and poor neurocognitive development) was linked to ZIKV infection in Brazil in 2015. Outbreaks and indications of transmission have spread quickly over the Americas, Africa, and other parts of the globe.Over 80 nations and territories have documented symptoms of Zika infection spread by mosquitoes,including microcephaly and Guillain-Barre syndrome(GBS).

关键词： infection Immune belongs

A Potential Degree Sequence Problem of the Loebl-Komlós-Sós Conjecture

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Acta Mathematicae Applicatae Sinica 2024年

作者： Guang-ming li Jian-hua YIN School of Mathematics and Statistics Hainan University

A non-increasing sequenceπ=(d1,..., dn) of nonnegative integers is said to be a graphic sequence if it is realizable by a simple graph G on n vertices. In this case, G is referred to as a realization ofπ. In terms of graphic sequences, the Loebl-Komlós-Sós conjecture states that for any integers k and n, if π=(d1,..., dn)is a graphic sequence with d「n/2」≥k, then every realization ofπcontains all trees with k edges as subgraphs.This problem can be viewed as a forcible degree sequence problem. In this paper, we consider a potential degree sequence problem of the Loebl-Komlós-Sós conjecture, that is, we prove that for any integers k and n, ifπ=(d1,..., dn) is a graphic sequence with d「n/2」≥k, then there is a realization ofπcontaining all trees with k edges as subgraphs.

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