检索结果-南通市图书馆

Modeling and Validation of Diamagnetic Rotor Levitated by Permanent Magnetics

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Mechanical Engineering 2024年第3期37卷 224-235页

作者： Yuanping Xu Yue Zhang jin Zhou Chaowu jin College of Mechanical and Electrical Engineering Nanjing University of Aeronautics and AstronauticsNanjing 210016China

As an innovative,low-power consuming,and low-stiffness suspension approach,the diamagnetic levitation technique has attracted considerable interest because of its potential applicability in miniaturized mechanical *** foundation of a diamagnetic levitation system is mathematical modeling,which is essential for operating performance optimization and stability ***,few studies on systematic mathematical modeling have been *** this study,a systematic mathematical model for a disc-shaped diamagnetically levitated rotor on a permanent magnet array is *** on the proposed model,the magnetic field distribution characteristics,diamagnetic levitation force characteristics(i.e.,levitation height and stiffness),and optimized theoretical conditions for realizing stable levitation are *** are conducted to verify the feasibility of the proposed mathematical *** predictions and experimental results indicate that increasing the levitation height enlarges the stable ***,with a further increase in the rotor radius,the stable regions of the rotor gradually diminish and even ***,when the levitation height is fixed,a moderate rotor radius permits stable *** study proposes a mathematical modeling method for a diamagnetic levitation system that has potential applications in miniaturized mechanical systems.

关键词： Diamagnetic levitation Magnetic levitation Rotor Modeling Validation Stability

Shor's algorithm does not factor large integers in the presence of noise

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

Science China(Information Sciences) 2024年第7期67卷 305-320页

作者： jin-Yi CAI College of Letters and Science University of Wisconsin

We consider Shor's quantum factoring algorithm in the setting of noisy quantum gates. Under a generic model of random noise for(controlled) rotation gates, we prove that the algorithm does not factor integers of the form pq when the noise exceeds a vanishingly small level in terms of n—the number of bits of the integer to be factored, where p and q are from a well-defined set of primes of positive density. We further prove that with probability 1-o(1) over random prime pairs(p, q), Shor's factoring algorithm does not factor numbers of the form pq, with the same level of random noise present.

关键词： random noise Shor's algorithm rotation gates quantum computing prime factorization

同方期刊数据库

Mobility of rhenium and selenium during chemical weathering and their implication for petrogenic organic carbon oxidation

在线全文

学校读者我要写书评

暂无评论

Science China Earth Sciences 2024年第3期67卷 740-750页

作者： Yuhong ZHANG jin WANG Yuanxin QU Chao ZHU Zhangdong jin State Key Laboratory of Loess and Quaternary Geology Institute of Earth EnvironmentChinese Academy of SciencesXi'an 710061China University of Chinese Academy of Sciences Beijing 100049China Xi'an Institute for Innovative Earth Environment Research Xi'an 710061China Institute of Global Environmental Change Xi'an Jiaotong UniversityXi'an 710049China

The oxidative weathering of petrogenic organic carbon(OC_(petro)) is an important source of carbon dioxide(CO_(2)) into the atmosphere on geological timescales and significantly influences the carbon cycle and global climate change. However, at present, a robust proxy to assess OC_(petro)oxidation is lacking. Riverine rhenium(Re) has emerged as a potential proxy to trace OC_(petro)oxidation, but little is known about Re sources and its relationship with OC_(petro)oxidation. To better understand the robustness of this proxy, we analyzed a shale weathering profile from the early Cambrian Shuijingtuo Formation in Chengkou County, Chongqing City, to address the mobility of Re and selenium(Se) and their relationship with the oxidation of OC_(petro)by analyses of the elemental variation and sequential extraction. The results showed that the chemical index of alteration(CIA)increases from the fresh bedrock to the weathered sections, indicating enhanced weathering intensity. Based on the sequential extraction and mass transfer coefficients(τ), Re and Se mainly exist in the organic phase of shale and are paired lost with OC_(petro) during weathering, with no obvious correlation with sulfide minerals. Furthermore, the different proportions of Re and Se loss with OC_(petro) loss can be attributed to their different geochemical behaviors during weathering. Our study supports Re as a robust proxy to trace OC_(petro) oxidation, whereas Se is the potential one. In the future, combined studies on various sedimentary rock profiles with catchment basins are needed to determine the sources of riverine Re and Se and their relationships with OC_(petro) oxidation.

关键词： Rhenium and selenium Shale Mobility OC_(petro) Chemical weathering

同方期刊数据库

Semi-analytical Solutions for Wellbores with Graded Skin Zones in Poroelastic Media

在线全文

学校读者我要写书评

暂无评论

Acta Mechanica Solida Sinica 2024年第3期37卷 385-395页

作者： Zhiqiang Fan Zhihe jin School of Mechanics Civil Engineering and ArchitectureNorthwestern Polytechnical UniversityXi’an710072China Department of Mechanical Engineering University of MaineOronoME04469USA

In analyzing the complex interaction between the wellbore and the reservoir formation,the hydromechanical properties of the region proximal to the wellbore,referred to as the“wellbore skin zone”,play a pivotal role in determining flow dynamics and the resulting formation *** models of the wellbore skin zone generally assume a constant permeability throughout,resulting in a sharp permeability discontinuity at the skin-reservoir *** paper introduces a model for a wellbore with a continuously graded skin zone of finite thickness within a poroelastic *** solutions are derived using the Laplace transform method,addressing both positive and negative skin *** results are presented to illustrate the effects of graded permeability/skin zone thickness on pore pressures and stresses around a *** results highlight a distinct divergence in stress and pore pressure fields when comparing wellbores with negative skin zones to those with positive skin zones or no skin at all.

关键词： Poroelastic Graded permeability Analytical solution Wellbore Skin zone

Combined Treatment with Bojungikgi-tang(Buzhong Yiqi Decoction)and Riluzole Attenuates Cell Death in TDP-43-Expressing Cells

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

Chinese Journal of Integrative Medicine 2024年第7期30卷 616-622页

作者： Eun jin Yang Department of KM Science Research Korea Institute of Oriental MedicineDaejeonYuseong-gu34054Republic of Korea

Objective To examine the effect of combined treatment with Bojungikgi-tang(BJIGT,Buzhong Yiqi Decoction)and riluzole(RZ)in transactive response DNA-binding protein 43(TDP-43)stress granule(SG)cells,a amyotrophic lateral sclerosis(ALS)cell line using transcriptomic and molecular *** TDP-43 SG cells were pretreated with BJIGT(100µg/mL),RZ(50µmol/L),and combined BJIGT(100µg/mL)/RZ(50µmol/L)for 6 h before treatment with lipopolysaccharide(LPS,200µmol/L).Cell viability assay was performed to elucidate cell toxicity in TDP-43 SC cells using a cell-counting kit-8(CCK8)assay *** expression levels of cell death-related proteins,including Bax,caspase 1,cleaved caspase 3 and DJ1 in TDP-43 SG cells were examined by Western blot *** autophagy-related proteins,including pmTOR/mTOR,LC3b,P62,ATG7 and Bcl-2-associated athanogene 3(Bag3)were investigated using immunofluorescence and immunoblotting *** Cell viability assay and Western blot analysis showed that combined treatment with BJIGT and RZ suppressed LPS-induced cell death and expression of cell death-related proteins,including Bax,caspase 1,and DJ1(P<0.05 or P<0.01).Immunofluorescence and immunoblotting assays showed that combined treatment with BJIGT and RZ reduced LPS-induced formation of TDP-43 aggregates and regulated autophagy-related protein levels,including p62,light chain 3b,Bag3,and ATG7,in TDP-43-expressing cells(P<0.05 or P<0.01).Conclusion The combined treatment of BJIGT and RZ might reduce inflammation and regulate autophagy dysfunction in TDP-43-induced ALS.

关键词： Bojungikgi-tang Buzhong Yiqi Decoction transactive response DNA-binding protein 43 autophagy oxidative stress amyotrophic lateral sclerosis

Bi-Frobenius Algebra Structures on Quantum Complete Intersections

在线全文

学校读者我要写书评

暂无评论

Acta Mathematica Sinica,English Series 2024年第6期40卷 1481-1504页

作者： Hai jin Pu ZHANG School of Mathematical Sciences Shanghai Jiao Tong UniversityShanghai 200240P.R.China

This paper is to look for bi-Frobenius algebra structures on quantum complete intersections over field *** find a class of comultiplications,such that if√−1∈k,then a quantum complete intersection becomes a bi-Frobenius algebra with comultiplication of this form if and only if all the parameters qij=±***,it is proved that if√−1∈k then a quantum exterior algebra in two variables admits a bi-Frobenius algebra structure if and only if the parameter q=±√*** if−1/∈k,then the exterior algebra with two variables admits no bi-Frobenius algebra *** prove that the quantum complete intersections admit a bialgebra structure if and only if it admits a Hopf algebra structure,if and only if it is commutative,the characteristic of k is a prime p,and every ai a power of *** also provides a large class of examples of bi-Frobenius algebras which are not bialgebras(and hence not Hopf algebras).In commutative case,other two comultiplications on complete intersection rings are given,such that they admit non-isomorphic bi-Frobenius algebra structures.

关键词： Bi-Frobenius algebras coalgebras bialgebras Hopf algebras quantum complete intersections quantum exterior algebras

Innovation and Firm Co-ownership Network in China’s Electric Vehicle Industry

在线全文

学校读者我要写书评

暂无评论

Chinese Geographical Science 2024年第2期34卷 195-209页

作者： jin Zerun ZHU Shengjun College of Urban and Environmental Sciences Peking UniversityBeijing 100871China Laboratory for Earth Surface Pro-cesses of the Ministry of Education Peking UniversityBeijing 100871China

Firms are embedded in complex networks,where diverse ideas combine and generate new *** of firms are of-ten seen as critical external resources that have significant influence on firm *** current literature tends to focus on the rela-tionship between firms and their shareholders,while paying less attention to the connections between firms with the same *** article identifies two types of network spillover effects,intra-city network effect and inter-city network effect,by visualizing the co-ownership networks in China’s electric vehicle(EV)*** find that firms with the same shareholders,which are defined as co-owned EV firms,are more innovative than non-co-owned ***,there are two dominant types of firm co-ownership ties formed by corporate and financial institution *** corporate shareholders help exploiting local tacit knowledge,financial institutions are more active in bridging inter-city *** conclusion is confirmed at both firm and city *** paper theor-izes the firm co-ownership network as a new form of institutional proximity and tested the result *** policy consideration,we have emphasized the importance of building formal or informal inter-firm network,and the government should further enhance the knowledge flow channel by institutional construction.

关键词： firm co-ownership intra-city network inter-city network technological innovation electric vehicle China

Suitable region of dynamic optimal interpolation for efficiently altimetry sea surface height mapping

在线全文

学校读者我要写书评

暂无评论

Geodesy and Geodynamics 2024年第2期15卷 142-149页

作者： Jiasheng Shi Taoyong jin School of Geodesy and Geomatics Hubei Luojia LaboratoryWuhan UniversityWuhan 430079China MOE Key Laboratory of Geospace Environment and Geodesy Wuhan UniversityWuhan 430079China

The dynamic optimal interpolation(DOI)method is a technique based on quasi-geostrophic dynamics for merging multi-satellite altimeter along-track observations to generate gridded absolute dynamic topography(ADT).Compared with the linear optimal interpolation(LOI)method,the DOI method can improve the accuracy of gridded ADT locally but with low computational ***,considering both computational efficiency and accuracy,the DOI method is more suitable to be used only for regional *** this study,we propose to evaluate the suitable region for applying the DOI method based on the correlation between the absolute value of the Jacobian operator of the geostrophic stream function and the improvement achieved by the DOI *** verifying the LOI and DOI methods,the suitable region was investigated in three typical areas:the Gulf Stream(25°N-50°N,55°W-80°W),the Japanese Kuroshio(25°N-45°N,135°E-155°E),and the South China Sea(5°N-25°N,100°E-125°E).We propose to use the DOI method only in regions outside the equatorial region and where the absolute value of the Jacobian operator of the geostrophic stream function is higher than1×10^(-11).

关键词： Dynamic optimal interpolation Linearoptimal interpolation Satellite altimetry Sea surface height Suitable region

A self-centering and stiffness-controlled MEMS accelerometer

在线全文

学校读者我要写书评

暂无评论

Microsystems & Nanoengineering 2024年第1期10卷 27-40页

作者： Yiming jin Zhipeng Ma Ziyi Ye Mingkang Li Xudong Zheng Zhonghe jin School of Aeronautics and Astronautics Zhejiang UniversityHangzhou 310013China Key Laboratory of Micro/Nano-Satellite Research of Zhejiang Province Hangzhou 310007PR China

This paper presents a high-performance MEMS accelerometer with a DC/AC electrostatic stiffness tuning capability based on double-sided parallel plates(DSPPs).DC and AC electrostatic tuning enable the adjustment of the effective stiffness and the calibration of the geometric offset of the proof mass,respectively.A dynamical model of the proposed accelerometer was developed considering both DC/AC electrostatic tuning and the temperature *** on the dynamical model,a self-centering closed loop is proposed for pulling the reference position of the forceto-rebalance(FTR)to the geometric center of *** self-centering accelerometer operates at the optimal reference position by eliminating the temperature drift of the readout circuit and nulling the net electrostatic tuning *** stiffness closed-loop is also incorporated to prevent the pull-in instability of the tuned low-stiffness accelerometer under a dramatic temperature ***-time adjustments of the reference position and the DC tuning voltage are utilized to compensate for the residue temperature drift of the proposed *** a result,a novel controlling approach composed of a self-centering closed loop,stiffness-closed loop,and temperature drift compensation is achieved for the accelerometer,realizing a temperature drift coefficient(TDC)of approximately 7μg/℃ and an Allan bias instability of less than 1μg.

关键词： stiffness electrostatic centering