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Design and testing of micro-tribometer with macro applied load

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Science China(Technological Sciences) 2016年第11期59卷 1666-1672页

作者： XU HongYi ZHANG ChenHui WU pu State Key Laboratory of Tribology Tsinghua University Shenzhen Key Laboratory of Micro-nano Manufacturing Research Institute of Tsinghua University in Shenzhen

With the development of superlubricity, the requirement for the accuracy of measuring super low friction force becomes more and more high. In this study, a novel micro-tribometer has been designed. The resolution and accuracy of friction force are 0.01 m N by using the dual frequency laser interferometer. Experiments were performed to investigate the ability of measuring friction force from different aspects. The interference signal mixed in the measured friction force curve was analyzed and can be removed by a designed filter. The results of experiment show that the tribometer is capable of measuring a super low friction force in the order of magnitude of 0.01 m N with an applied load up to 1 N.

关键词： friction test methods dual-frequency laser interferometer bender piezo actuator

Improved unequal interval grey model and its applications

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Journal of Systems Engineering and Electronics 2011年第3期22卷 445-451页

作者： Yuhong Wang Yaoguo Dang Xujin pu School of Business Jiangnan UniversityWuxi 214122P.R.China College of Economics and Management Nanjing University of Aeronautics and AstronauticsNanjing 210016P.R.China

A new method to improve prediction precision of GM（1,1） model with unequal time interval is *** grey derivative is multiplied by a parameter to guarantee the time response function satisfying approximately exponential function *** simplify the process of parametric estimation,an approximate value is taken for the multiplied *** the estimators of coefficient of development and grey action quantity can be *** the same time,the principle of the new information priority is also *** take the last item of the first-order accumulated generation operator（1-AGO） on raw data sequence as the initial condition in the time response *** the new information can be taken full advantage of through the improved initial *** properties of this new model are also *** presented method is actually a combination of improvement of grey derivative and improvement of the initial *** results of an example indicate that the proposed method can improve prediction precision prominently.

关键词： grey derivative initial condition GM(1 1) model unequal interval.

Experimental study of lightweight aggregate concrete under multiaxial stresses

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2010年第8期11卷 545-554页

作者： Han-yong LIU Yu-pu SONG Structural Engineering Institute School of Civil Engineering Faculty of lnfrastructure Engineering Dalian University of Technology Dalian 116024 China

Lightweight aggregate concrete cube specimens (100 mm×100 mm×100 mm) and plate specimens (100 mm×100 mm×50 mm) were tested under biaxial compression-compression (CC) and compression-tension (CT) load combinations. For comparison, normal concrete plate specimens (100 mm×100 mm×50 mm) were tested under the same load combinations. Based on the test results, a two-level strength criterion of lightweight aggregate concrete in both octahedral stress coordinate and principal stress coordinate was suggested. The lightweight aggregate concrete cube specimens (100 mm×100 mm×100 mm) were then tested under triaxial compression-compression-compression (CCC) load combination with corresponding tests on normal concrete cube specimens (100 mm×100 mm×100 mm). The effect of intermediate principal stress on triaxial compressive strength is further examined. A "plastic flow plateau" area was apparent in principal compressive stress-strain relationships of lightweight aggregate concrete but not in normal concrete. A quadratic formula was suggested for the expression of strength criterion under triaxial compression.

关键词： Lightweight aggregate concrete Normal concrete Biaxial loads Triaxial loads Compressive strength Tensile strength Stress-strain relationships Plastic flow plateau Lode angle

Understanding diabetic retinopathy

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Science China(Life Sciences) 2015年第6期58卷 519-520页

作者： pu MingLiang Department of Anatomy School of Basic Medical Sciences Peking University

A recent survey shows that diabetes affect 92.4 million people in China's Mainland [1], among which 16.9 million have diabetic retinopathy （DR） [2]. DR is one of the major causes of blindness in the working age population in both developing and developed countries. Although the exact mechanism by which diabetes causes retinopathy remains elusive, several hypotheses have been postulated to explain pathogenies of the disease. Here we invited five groups of scientists and clinicians to share their recent discoveries and expert opinions in molecular biology, pathophysiology, genetics, and epigenetics of DR.

关键词：糖尿病视网膜病变表观遗传学病性中国大陆地区发展中国家分子生物学病理生理学发达国家

TAILING WAVETRAIN GENERATION IN PRECURSOR SOLITON GENERATION IN TWO-LAYER FLOW

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Acta Mechanica Sinica 2000年第1期16卷 1-7页

作者：徐肇廷徐昊 Samuel Shan-pu Shen Institute of Physical Oceanography and Physical Oceanography Lab. Ocean University of QingdaoQingdao 266003China Key Lab.of Marine Science & Numerical Modeling State Oceanic AdministrationQingdao 266003China Department of Mathematical Sciences University of Alberta EdmontonAlberta T6G 2G1Canada

A theory of tailing wavetrain generation for the precursor soliton generation in two-layer flow is presented by using averaged KdV equations (AKdV), which are derived by the authors in terms of Whitham's method of averaging([1,2]). From the AKdV equations, group velocities of the tailing wavetrain generation are obtained by means of generating conditions of the tailing wavetrains, furthermore an analytical solution of the tailing wavetrain generation is found theoretically. A comparison between the theoretical and numerical results is carried out in the present paper, which shows that the theoretical results are in good agreement with the numerical ones, obtained from the fKdV equation in two-layer flow with the depth of unity in the rest.

关键词： tailing wavetrain group velocity soliton two-layer flow

Characterization of Lipschitz Functions via Commutators of Multilinear Singular Integral Operators in Variable Lebesgue Spaces

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Acta Mathematica Sinica,English Series 2023年第12期39卷 2465-2488页

作者： Jiang Long WU pu ZHANG Department of Mathematics Mudanjiang Normal UniversityMudanjiang 157011P.R.China

Let 6=(bi,b2,...,bm)be a collection of locally integrable functions and T,the com-mutator of multilinear singular integral operator *** by L(δ)and L(δ(·))the Lipschitz spaces and the variable Lipschitz spaces,*** main purpose of this paper is to establish some new characterizations of the(variable)Lipschitz spaces in terms of the boundedness of multilinear commutator T∑b in the context of the variable exponent Lebesgue spaces,that is,the authors give the necessary and sufficient conditions for bj(j=1,2,...,m)to be L(δ)or L(δ(·))via the boundedness of multilinear commutator from products of variable exponent Lebesgue spaces to variable exponent Lebesgue *** authors do so by applying the Fourier series technique and some pointwise esti-mate for the *** key tool in obtaining such pointwise estimate is a certain generalization of the classical sharp maximal operator.

关键词： Multilinear commutator singular integral operator Lipschitz function variable exponent

H _ index based fault estimation for micro quad-rotor

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Journal of Systems Engineering and Electronics 2014年第3期25卷 483-488页

作者： pu Yang Zhixia Yin Bin Jiang School of Automation Nanjing University of Aeronautics and Astronautics Flight Test Center of Commercial Aircraft Corporation of China Limited

Taking the attitude control system of micro quad-rotor as a research object, a design scheme of fault estimator based on generalized Kalman-Yakubovic-Popov （GKYP） lemma is put forward to deal with the problem of estimating multiple actuators malfunctions with couplings. Using an H_index and an appropriate algorithm, the goal of weakening the coupling can be achieved by limiting the fault frequency to a certain range, then different kinds of actuator faults can be estimated correctly. The simulations demonstrate the reliability and validity of the proposed method.

关键词： micro quad-rotor fault estimation generalized Kalman-Yakubovic-Popov (GKYP) lemma.

Precipitated phases of superaustenitic stainless steel 654SMO

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Journal of Iron and Steel Research International 2017年第7期24卷 743-749页

作者： Zhi-gang Song En-xiang pu Special Steel Institute Central Iron & Steel Research Institute School of Materials Science and Engineering Tsinghua University

The phase diagram of superaustenitic stainless steel 654SMO was calculated by thermodynamic software and the precipitated phases in the specimens aged at 800-1100°C for 1hwere studied by methods of physicochemical phase analysis,scanning electron microscopy and transmission electron *** results showed that the size of precipitated particles increased with increasing the *** amount of second phases reached the maximum value at 900°C,but decreased above 900°*** were about eight kinds of precipitated phases in 654SMO includingσphase,Cr_2N,μphase,χphase,Laves phase,M_（23）C_6,M_6C and M_3C,in which theσphase and Cr_2N were the dominant precipitated phases.

关键词： 654SMO Precipitation Superaustenitic stainless steel Precipitated phase Second phase

Experimental study on the seismic performance of new sandwich masonry walls

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Earthquake Engineering and Engineering Vibration 2013年第1期12卷 77-86页

作者： Xiao Jianzhuang pu Jie Hu Yongzhong Department of Building Engineering Tongji University State Key Laboratory for Disaster Reduction in Civil Eng. Tongji University

Sandwich masonry walls are widely used as energy-saving panels since the interlayer between the outer leaves can act as an insulation *** types of sandwich walls are continually being introduced in research and applications,and due to their unique bond patterns,experimental studies have been performed to investigate their mechanical properties,especially with regard to their seismic *** this study,three new types of sandwich masonry wall have been designed,and cyclic lateral loading tests were carried out on five *** results showed that the specimens failed mainly due to slippage along the bottom cracks or the development of diagonal cracks,and the failure patterns were considerably influenced by the aspect *** was undertaken on the seismic response of the new walls,which included ductility,stiffness degradation and energy dissipation capacity,and no obvious difference was observed between the seismic performance of the new walls and traditional *** were made between the experimental results and the calculated results of the shear *** is concluded that the formulas in the two Chinese codes（GB 50011 and GB 50003） are suitable for the calculation of the shear capacity for the new types of walls,and the formula in GB 50011 tends to be more conservative.

关键词： sandwich wall seismic performance shear behavior cyclic loading test