检索结果-南通市图书馆

A proposal on complementary determination of the effective electro-weak mixing angles via doubly heavy-flavored hadron production at a super Z-factory

在线全文

学校读者我要写书评

暂无评论

Science China(Physics,Mechanics & Astronomy) 2020年第8期63卷 61-70页

作者： Xu-chang Zheng Chao-Hsi chang Tai-Fu Feng Key Laboratory of Theoretical Physics Institute of Theoretical PhysicsChinese Academy of SciencesBeijing 100190China School of Physical Sciences University of Chinese Academy of SciencesBeijing 100049China Department of Physics Chongqing UniversityChongqing 401331China China Center of Advanced Science and Technology(CCAST)(world Laboratory) Beijing 100190China Department of Physics Hebei UniversityBaoding 071002China

To test the standard model(SM)precisely and to look for the clues deviating from SM,a proposal for determining the effective electro-weak mixing angles sin2θefff(particularly f=lept,c,b)is *** is via observing the asymmetries(the forward-backward one AFB,the left-right one ALR and the combined left-right forward-backward one ALRFB)of the doubly heavy-flavored hadrons in the production at a super Z-factory(an e+e-collider designed with a luminosity as high as possible for modernday techniques runs around the center-of-mass energy s1/2=mZ).To see the sensitivity,uncertainties as well as the event accumulation precisely,the observables for describing the asymmetries of the produced hadrons are computed numerically with varying effective mixing angles,and based on the result analyses,it is concluded that the proposal may offer an independent complement determination of the effective mixing angles.

关键词： electro-weak mixing angle production of doubly heavy-flavored hadron asymmetries super Z-factory

Effect of heat treatment on microstructure and mechanical properties of selective laser-melted PH13-8Mo stainless steel

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2024年第4期31卷 945-955页

作者： Yuan Zhang Xiang Liu chang-jun wang chang Liu School of Material Science and Engineering Kunming University of Science and TechnologyKunming 650093YunnanChina Central Iron&Steel Research Institute Co. Ltd.Beijing 100081China

PH13-8Mo stainless steel powder with high sphericity and well fluidity was prepared by the plasma rotating electrode *** formed parts with ultra-high purity were manufactured by selective laser *** tensile and impact mechanical properties of the printed parts under three heat treatment regimes were compared to those without heat *** microstructure,grain orientation and phase composition were characterized by electron-backscatter diffraction,X-ray diffraction and transmission electron *** characterization results reveal that the addition of heat treatment makes the grains enlarge,and after different heat treatments,the average grain size from 1.51μm in the printed state increases to 2.78,3.09 and 2.06μm,*** formed parts are mainly composed of martensite and retained ***,the NiAl and M23C precipitates form,which are the major strengthening phases of PH13-8Mo stainless *** optimal heat treatment process is 925℃×1 h water cooling.w.)+0℃×2 h air cooling(AC)+540℃×4 h *** this heat treatment process,PH13-8Mo formed parts have the optimal comprehensive mechanical properties:the tensile strength,yield strength and impact energy KU2 are 1492 MPa,1432 MPa and 63 J,*** strengthening and toughening via heat treatment are mainly attributed to dislocation strengthening,the formation of NiAl and M23Co precipitates and the change of volume fraction of the retained austenite.

关键词： High-strength stainless steel-Selective laser melting-Heat treatment Microstructure Mechanical property

Extensions of nonlinear error propagation analysis for explicit pseudodynamic testing

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

Earthquake Engineering and Engineering Vibration 2009年第1期8卷 77-86页

作者： Shuenn-Yih chang Department of Civil Engineering Taipei University of Technology NTUT Box 2653 Chinese Taipei 106-08

Two important extensions of a technique to perform a nonlinear error propagation analysis for an explicit pseudodynamic algorithm （chang, 2003） are presented. One extends the stability study from a given time step to a complete step-by-step integration procedure. It is analytically proven that ensuring stability conditions in each time step leads to a stable computation of the entire step-by-step integration procedure. The other extension shows that the nonlinear error propagation results, which are derived for a nonlinear single degree of freedom （SDOF） system, can be applied to a nonlinear multiple degree of freedom （MDOF） system. This application is dependent upon the determination of the natural frequencies of the system in each time step, since all the numerical properties and error propagation properties in the time step are closely related to these frequencies. The results are derived from the step degree of nonlinearity. An instantaneous degree of nonlinearity is introduced to replace the step degree of nonlinearity and is shown to be easier to use in practice. The extensions can be also applied to the results derived from a SDOF system based on the instantaneous degree of nonlinearity, and hence a time step might be appropriately chosen to perform a pseudodynamic test prior to testing.

关键词： nonlinear error propagation explicit pseudodynamic algorithm stability condition step-by-step integration procedure step degree of nonlinearity

Starting flow in a rotating parallel plate channel

在线全文

学校读者我要写书评

暂无评论

Acta Mechanica Sinica 2012年第5期28卷 1271-1276页

作者： chang Yi wang Department of Mathematics Michigan State University

The starting flow due to a suddenly applied pressure gradient in a parallel plate channel which is rotating as a system is studied. Exact analytic series solutions to the unsteady Navier-Stokes equations are found by both the Laplace transform method and the separation of parameters method, the latter is shown to be superior. Rotation not only induces a secondary transverse flow but also alters the character of the transient flow rate and velocity profiles. Back flow and inertial oscillations occur, especially at higher rota- tion rates.

关键词： Rotating system Flow - Starting

The effects of hydrogen on the helium behavior in palladium

在线全文

学校读者我要写书评

暂无评论

Nuclear Science and Techniques 2016年第5期27卷 114-119页

作者： chang-Ning Peng Electrical Engineering College Longdong University

As one candidate of tritium storage materials,palladium subjects to the damage from helium atoms introduced by the(3-decay of tritium *** mechanical properties of palladium will be greatly degraded deriving from the accumulation of helium atoms.A set of interatomic potentials has been fitted based on ab initio calculation according to the Morse *** dynamic methods are utilized to investigate the existence of H atoms on the release of helium atoms from palladium with the present fitted *** is found that hydrogen atoms play significant roles in the diffusion and release of helium *** presence of hydrogen atoms tends to obstacle the diffusion and release of helium atoms in palladium.

关键词：氦原子氢原子行为钯分子动力学存储材料机械性能莫尔斯

Nonlinear evaluations of unconditionally stable explicit algorithms

在线全文

学校读者我要写书评

暂无评论

Earthquake Engineering and Engineering Vibration 2009年第3期8卷 329-340页

作者： Shuenn-Yih chang Department of Civil Engineering Taipei University of Technology

Two explicit integration algorithms with unconditional stability for linear elastic systems have been successfully developed for pseudodynamic testing. Their numerical properties in the solution of a linear elastic system have been well explored and their applications to the pseudodynamic testing of a nonlinear system have been shown to be feasible. However, their numerical properties in the solution of a nonlinear system are not apparent. Therefore, the performance of both algorithms for use in the solution of a nonlinear system has been analytically evaluated after introducing an instantaneous degree of nonlinearity. The two algorithms have roughly the same accuracy for a small value of the product of the natural frequency and step size. Meanwhile, the first algorithm is unconditionally stable when the instantaneous degree of nonlinearity is less than or equal to 1, and it becomes conditionally stable when it is greater than 1. The second algorithm is conditionally stable as the instantaneous degree of nonlinearity is less than 1/9, and becomes unstable when it is greater than 1. It can have unconditional stability for the range between 1/9 and 1. Based on these evaluations, it was concluded that the first algorithm is superior to the second one. Also, both algorithms were found to require commensurate computational efforts, which are much less than needed for the Newmark explicit method in general structural dynamic problems.

关键词： explicit integration algorithms unconditional stability pseudodynamic algorithm nonlinear system instantaneous degree of nonlinearity

An updated constraint on the local stratigraphy at the chang'E-4 landing site

在线全文

学校读者我要写书评

暂无评论

Earth and Planetary Physics 2021年第1期5卷 19-31页

作者： YiRen chang ZhiYong Xiao YiChen wang ChunYu Ding Jun Cui YuZhen Cai State Key Laboratory of Lunar and Planetary Sciences Macao University of Science and TechnologyMacao 999078China Planetary Environmental and Astrobiological Research Laboratory School of Atmospheric SciencesSun Yat-sen UniversityZhuhaiGuangdong 519000China Center for Excellence in Comparative Planetology Chinese Academy of SciencesHefei 230000China National Astronomical Observations of China Chinese Academy of SciencesBeijing 100000China

The chang’E-4 mission has been exploring the lunar *** scientific targets of the rover onboard are(1)resolving the possible mineralogy related to the South Pole-Aitken basin and(2)understanding the subsurface processes at the lunar *** to date that are based on the reflectance spectra and radar data obtained by the rover have shown a persistent inconsistency about the local *** explain both the abnormal surface topography at the landing site and the unexpected radargram observed by the rover,the Alder crater has been frequently reported to be older than the mare basalts at that landing ***,this argument is not supported by earlier geological mapping nor recent crater *** this controversy is critical for a full understanding of the geological history of the landing area and for correct interpretations of the scientific data *** detailed crater statistics,rigorous statistical analyses,and an updated crater chronology function,this study is determined to resolve the relative ages of the Alder crater,Finsen crater,and the mare basalts on the floor of Von Kármá*** results reveal that while background secondaries and local resurfacing have widely occurred in the study area,affecting age determinations,the statistics are significant enough to conclude that the Alder crater is the oldest among the three *** independent constraint is consistent with both the crosscutting relationships of different terrains in this area and global stratigraphic *** results exclude Alder as a possible contributor of the post-mare deposits at the landing site,appealing for a more systematic stratigraphy study to resolve the provenances of these deposits.

关键词： Moon chang'E-4 impact craters absolute model age stratigraphy

Neurotoxicity of tetramethylammonium ion on larval and juvenile zebrafish:Effects on neurobehaviors and multiple biomarkers

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2024年第9期143卷 138-147页

作者： Ruixin Zhang Rui wang Jiajun chang gDaniel Sheng Daqiang Yin Key Laboratory of Yangtze River water Environment Ministry of EducationCollege of Environmental Science and EngineeringTongji UniversityShanghai 200092China Shanghai Institute of Pollution Control and Ecological Security Shanghai 200092China

Tetramethylammonium hydroxide(TMAH)is an important compound that utilized and released by the rapidly expanding semiconductor industry,which could hardly be removed by the conventional wastewater treatment *** a cholinergic agonist,the tetramethylammonium ion(TMA^(+))has been reported to induce toxicity to muscular and respiratory systems of mammals and human,however the toxicity on aquatic biota remains poorly *** investigated the neurotoxic effects of TMA^(+)exposure on zebrafish,based on neurobehavior tests and a series of *** inhibitions on the swimming distance of zebrafish larvae were observed when the exposure level exceeded 50 mg/L,and significant alterations on swimming path angles(straight and deflective movements)occurred even at 10 mg/*** tested neurobehavioral endpoints of zebrafish larvae were significantly positively correlated with reactive oxygen species(ROS)and malondialdehyde(MDA),significantly negatively related with the activities of antioxidant enzymes,but not significantly correlated with the level of acetylcholinesterase(AChE).Such relationship indicates that the observed neurotoxic effects on swimming behavior of zebrafish larvae is mainly driven by oxidative stress,rather than the alterations of *** the highest exposure concentration(200 mg/L),TMA^(+)evoked more severe toxicity on zebrafish juveniles,showing significantly stronger elevation on the MDA activity,and greater inhibitions on the activities of antioxidant enzymes and ACh E,suggesting juveniles were more susceptible to TMA^(+)exposure than larval zebrafish.

关键词： Tetramethylammonium Zebrafish Oxidative stress Acetylcholinesterase Neurobehavior

Overexpression of the promyelocytic leukemia gene suppresses growth of human bladder cancer cells by inducing gl cell cycle arrest and apoptosis

在线全文

学校读者我要写书评

暂无评论

Chinese Medical Journal 2003年第9期116卷 1394-1398页

作者：贺大林南勋义 chang Kun-Song 王亚峰 Chung Leland w.K. Department of Urology First Hospital Xi'an Jiaotong UniversityXi'an 710061 China Division of Laboratory Medicine University of Texas MD Anderson Cancer Center USA Department of Urology University of Virginia USA

Objectives To examine the anti-oncogenic effects of promyelocytic leukemia (PML) on bladder cancer and to explore its molecular mechanisms of growth *** wild-type PML was transfected into bladder cancer cells (5637 cell) and expressed in a replication-deficient adenovirus-mediated gene delivery system and introduced into human bladder cancer cells (5637 cell) in vitro and in vivo. The effect and mechanisms of the PML gene in cell growth, clonogenicity, and tumorigenicity of bladder cancer cells were studied using in vitro and in vivo growth assays, soft agar colony-forming assay, cell cycle analysis, apoptosis assay and in vivo tumorigenicity *** Overexpression of PML in 5637 cells significantly reduced their growth rate and clonogenicity on soft agar. PML suppressed bladder cancer cell growth by inducing g1 cell cycle arrest and apoptosis. Adenovirus-mediated PML ( Ad-PML) significantly suppressed the tumorigenicity and growth of bladder cancer cells. Intratumoral injection of Ad-PML into tumors induced by 5637 cells dramatically suppressed their *** The results indicated that overexpression of PML protein may promote efficient growth inhibition of human bladder cancer cells by inducing g1 cell cycle arrest and apoptosis, and adenovirus-mediated PML (Ad-PML) expression efficiently suppresses human bladder cancer growth.

关键词： bladder neoplasms.leukemia promyelocytic.g1 arrest .apoptosis