检索结果-南通市图书馆

Three-dimensional ray-tracing simulation of fast magnetoacoustic waves in a stratified solar atmosphere

在线全文

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2017年第10期60卷 1570-1576页

作者： liu NiGang ZHENG HuiNan su ZhenPeng CAS Key Laboratory of Geospace Environment Department of Geophysics and Planetary Sciences University of Science and Technology of China Hefei 230026 China Collaborative Innovation Center of Astronautical Science and Technology University of Science and Technology of China Hefei 230026 China

In the solar atmosphere, there exist two frequently-observed phenomena, Moreton waves and EIT(extreme-ultraviolet imaging telescope) waves, whose physical nature is still under debate. In this work, we perform a three-dimensional ray-tracing simulation for the propagation of fast magnetoacoustic waves. We build a stratified solar atmosphere model and take partial ionization into consideration to give an exact description of chromosphere and transition region. The calculated result is compared with a flare event observation in which both Moreton waves and EIT waves were present. In agreement with observations, the calculated wavefront show different kinematical characteristics in different propagation directions during different *** waves and EIT waves have higher propagation speeds near the active region where the magnetic field strength is strong. The result suggests that both Moreton waves and EIT waves of this event can be interpreted as the fast magnetoacoustic waves propagating at different heights in the solar atmosphere.

关键词： solar atmosphere fast waves ray-tracing

Non-Markovian and Non-Perturbative Entanglement Dynamics of Biomolecular Excitons

在线全文

学校读者我要写书评

暂无评论

Chinese Physics Letters 2011年第8期28卷 344-347页

作者： liu Zhi-Qiang LIANG xian-Ting Department of Physics and Institute of Modern Physics Ningbo UniversityNingbo 315211

We investigate the entanglement dynamics of two coupled chromophore pairs embedded in a protein-solvent *** non-Markovian and non-perturbative hierarchical expansion technique is used in the solution of the quantum *** spectral distribution function of the bath is set with the Drude–Lorentz *** is shown that the evolutions of the entanglement described by the measures of negativity and concurrence are in agreement with each *** decay to zero in a short time and the sudden death and sudden birth can be observed in the process of the evolutions of the entanglement.

关键词： dynamics decay Lorentz

Inhibition of thrombin by functionalized C_(60)nanoparticles revealed via in vitro assays and in silico studies

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2018年第1期30卷 285-295页

作者： Yanyan liu Jianjie Fu Wenxiao Pan Qiao Xue xian liu Aiqian Zhang State Key Laboratory of Environmental Chemistry and Ecotoxicology Research Center for Eco-Environmental SciencesChinese Academy of SciencesBeijing 100085China College of Resources and Environment University of Chinese Academy of SciencesBeijing 100190China Institute of Environment and Health Jianghan UniversityWuhan 430056China

The studies on the human toxicity of nanoparticles（NPs） are far behind the rapid development of engineered functionalized NPs. Fullerene has been widely used as drug carrier skeleton due to its reported low risk. However, different from other kinds of NPs, fullerene-based NPs（C_（60） NPs） have been found to have an anticoagulation effect, although the potential target is still unknown. In the study, both experimental and computational methods were adopted to gain mechanistic insight into the modulation of thrombin activity by nine kinds of C_（60） NPs with diverse surface chemistry properties. In vitro enzyme activity assays showed that all tested surface-modified C_（60） NPs exhibited thrombin inhibition ability. Kinetic studies coupled with competitive testing using 3 known inhibitors indicated that six of the C_（60） NPs, of greater hydrophobicity and hydrogen bond（HB） donor acidity or acceptor basicity, acted as competitive inhibitors of thrombin by directly interacting with the active site of thrombin. A simple quantitative nanostructure-activity relationship model relating the surface substituent properties to the inhibition potential was then established for the six competitive *** docking analysis revealed that the intermolecular HB interactions were important for the specific binding of C_（60） NPs to the active site canyon, while the additional stability provided by the surface groups through van der Waals interaction also play a key role in the thrombin binding affinity of the NPs. Our results suggest that thrombin is a possible target of the surface-functionalized C_（60） NPs relevant to their anticoagulation effect.

关键词： Thrombin C_(60) nanoparticle(NP) surface modification Activity inhibition Quantitative nanostructure-activity relationship Molecular docking

Recent advances in active sites identification and regulation of M-N/C electro-catalysts towards ORR

在线全文

学校读者我要写书评

暂无评论

Science China Chemistry 2019年第6期62卷 669-683页

作者： Jie liu Zhao Jin xian Wang Junjie Ge Changpeng liu Wei Xing State Key Laboratory of Electroanalytical Chemistry Changchun Institute of Applied Chemistry Chinese Academy of Sciences University of Science and Technology of China Laboratory of Advanced Power Sources Changchun Institute of Applied Chemistry Chinese Academy of Sciences Jilin Province Key Laboratory of Low Carbon Chemical Power Sources

Transition metal and nitrogen co-doped carbon(M–N/C) catalysts are recognized as the most prospective alternatives for platinum-based electro-catalysts towards oxygen reduction reaction(ORR) in polymer electrolyte fuel cells. Recently, significant progress has been achieved in the identification and regulation of active sites of this kind of catalysts. In this mini review,we summarize the techniques and strategies to identify active sites in M–N/C catalysts, the main debates on active sites types, the measurement method for active site density, the reactivity descriptors for M–N/C catalysts, and directions to the design of ORR M–N/C catalysts.

关键词： ORR electro-catalysts M–N/C active sites

Development and Application of On-line Wind Power Risk Assessment System

在线全文

学校读者我要写书评

暂无评论

电力系统自动化 2012年第8期36卷 161-165页

作者： su, Feng Zhou, Xiaoxin Yu, Haiguo xian, Wenjun Lü, Ying Ren, Lingyu Power System Department China Electric Power Research Institute Beijing 100192 China Qinghai Electric Power Dispatch Center Xining 810008 China

Because of the large-scale integration of wind power,the dynamic characteristics of power system have many uncertain *** on deterministic analysis methods,traditional on-line security assessment system cannot quantitatively estimate the actual operating conditions of the power system for only considering the most serious and credible ***,the risk theory is introduced into an on-line security assessment system and then an on-line risk assessment system for wind power is designed and implemented by combining with the dynamic security assessment *** on multiple data integration,the wind power disturbance probability is available and the security assessment of the power grid can obtain security indices in different *** operating risk index is an expectation of severity,computed by summing up all the products of the result probability and its *** results are reported to the dispatchers in on-line environment,while the comprehensive weak links are automatically provided to the power dispatching *** risk assessment system in operation can verify the reasonableness of the system.

关键词：安全评估系统风力发电系统风险理论应用开发定性分析方法动态安全评估电力调度中心

Undersea safety mining of the large gold deposit in Xinli District of Sanshandao Gold Mine

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2012年第7期19卷 574-583页

作者： Zhi-xiang liu Wen-gang Dang xian-qun He School of Resources and Safety Engineering Central South University Changsha 410083 China

The exploration of undersea resources becomes popular as land resources decrease. Researches were conducted with emphasis on the safety and efficiency of undersea mining of the large gold deposit in Xinli District of Sanshandao Gold Mine. A series of tests for the physical and mechanical characteristics of rock mass were carried out, and the three-dimensional geo-stress distribution was tested in the mining area. Further, a similar experimental simulation platform, which revealed the mechanism of water inrush and ascertained the reason- able thickness of the safety isolate layer, was established for the undersea mining. Meanwhile, the feasibility of cancelling the ore pillars and the safety conditions was checked by numerical simulation. The simulation results show that it is safe to exploit the ore body below the -85 m level （presently, the exploitation level is below -160 m in Xinli District）, and the ore pillars can be cancelled below the -560 m level. Fur- thermore, a novel backfill method was designed to reduce the rock strata disturbance and settlement, and the settlement of roof strata was monitored during the mining process. Engineering practice shows that the settlement of roof strata was small and that no disaster happened. This indicates that the undersea safety mining technology of the large gold deposit is achieved in Xinli District.

关键词： undersea mining gold deposits rock mechanics mine roof control computer simulation

Mechanical properties and microstructure of 3D-printed high Co–Ni secondary hardening steel fabricated by laser melting deposition

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2017年第9期24卷 1027-1033页

作者： Hui-ping Duan Xiao liu xian-zhe Ran Jia Li Dong liu School of Materials Science and Engineering Beihang UniversityBeijing 100191China National Engineering Laboratory of Additive Manufacturing for Large Metallic Components Beijing 100191China Engineering Research Center of Ministry of Education on Laser Direct Manufacturing for Large Metallic Component Beijing 100191China

The mechanical properties and microstructure of the 3D-printed high Co–Ni secondary hardening steel fabricated by the laser melting deposition technique was investigated using a material testing machine and electron microscopy. A microstructure investigation revealed that the samples consist of martensite laths, fine dispersed precipitates, and reverted austenite films at the martensite lath boundaries. The precipitates are enriched with Co and Mo. Because the sample tempered at 486°C has smaller precipitates and a higher number of precipitates per unit area, it exhibits better mechanical properties than the sample tempered at 498°C. Although the 3D-printed samples have the same phase constituents as Aer Met 100 steel, the mechanical properties are slightly worse than those of the commercial wrought Aer Met 100 steel because of the presence of voids.

关键词： laser deposition high strength steel mechanical properties microstructure

Hydration process in Portland cement blended with activated coal gangue

在线全文

学校读者我要写书评

暂无评论

Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2011年第7期12卷 503-510页

作者： xian-ping liu Pei-ming WANG Min-ju DING Key Laboratory of Advanced Civil Engineering Materials (Tong/i University) Ministry of Education Shanghai 201804 China State Key Laboratory Breeding Base of Crime Scene Evidence Shanghai 200083 China

This paper deals with the hydration of a blend of Portland cement and activated coal gangue in order to determine the relationship between the degree of hydration and compressive strength *** hydration process was investigated by various means:isothermal calorimetry,thermal analysis,non-evaporable water measurement,and X-ray diffraction *** results show that the activated coal gangue is a pozzolanic material that contributes to the hydration of the cement *** pozzolanic reaction occurs over a period of between 7 and 90 d,consuming portlandite and forming both crystal hydrates and ill-crystallized calcium silicate *** hydrates are similar to those found in pure Portland *** results show that if activated coal gangue is substituted for cement at up to 30%(w/w),it does not significantly affect the final compressive strength of the blend.A long-term compressive strength improvement can in fact be achieved by using activated coal gangue as a sup-plementary cementing *** relationship between compressive strength and degree of hydration for both pure Portland cement and blended cement can be described with the same ***,the parameters are different since blended cement produces fewer calcium silicate hydrates than pure Portland cement at the same degree of hydration.

关键词： Activated coal gangue Portland cement Blended cement Hydration Strength

Test research on sticking mechanism during hot rolling of suS 430 ferritic stainless steel

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2010年第5期17卷 573-578页

作者： Jun-xian liu Yong-jun Zhang Jing-tao Han School of Materials Science and Engineering University of Science and Technology Beijing Beijing 100083 China

The sticking phenomenon during hot rolling of suS 430 ferritic stainless steel was investigated by means of a two-disc type high-temperature wear tester. The test results indicate that sticking particles on the surfaces of high chromium steel （HiCr） and high-speed steel （HSS） rolls undergo nucleation, growth, and saturation stages. Grooves on the roll surface generated by grinding provide nucleation sites for sticking particles. The number of sticking particles on the HiCr roll surface is greater than that on the HSS roll surface. The average surface roughnesses （Ra） of HiCr and HSS rolls change from 0.502 and 0.493 μm at the initial stage to 0.837 and 0.530 μm at the saturation stage, respectively. The test further proves that the sticking behavior is strongly dependent on roll materials, and the HSS roll is more benefi- cial to prevent particles sticking compared with the HiCr roll under the same hot-rolling conditions.

关键词： ferritic steel stainless steel hot rolling sticking rolls