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Preventive and control system for the life cycle of a pandemic

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Journal of Safety Science and Resilience 2022年第4期3卷 321-329页

作者： Chenyang Wang Rui ba Ranpeng Wang Hui Zhang Department of Engineering Physics Tsinghua UniversityBeijing 100084China

Herein,a matching method for varied epidemic phase characteristics and appropriate strategies is presented,aiming at the complexities of the novel coronavirus disease 2019 pandemic and the hysteresis of *** classical diffusion dynamic models of the epidemic spread are ***,the bass diffusion model is selected to study more characteristics of an epidemic,such as the diversities in regional internal and external infection ***,the classical division method vis-à-vis a pandemic life cycle is improved.A specific approach is proposed to portray more detailed characteristics of the pandemic by dividing it into more ***,a four-level epidemic prevention and control measure system is *** applicable phases and strategic effectiveness of each measure are integrated into the different phases of the pandemic life ***,the matching method is applied to analyze two cases of the spread of the outbreak in cities and significant *** findings provide a certain reference for the effectiveness of the matching method in the post-peak epidemic period.

关键词： Pandemic Life cycle Prevention and control system

Velocity field of wave-induced local fluid flow in double-porosity media

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Science China(Physics,Mechanics & Astronomy) 2014年第6期57卷 1020-1030页

作者： ba Jing ZHANG Lin SUN WeiTao HAO ZhaoBing Geophysical Department Research Institute of Petroleum Exploration and Development School of Geosciences China University of Petroleum (Eastern China) Zhou Pei-Yuan Center for Applied Mathematics Tsinghua University Key Laboratory of Integrative Researches on Geophysics for Petroleum Institute of Geology and GeophysicsChinese Academy of Sciences

Under the excitation of elastic waves,local fluid flow in a complex porous medium is a major cause for wave dispersion and *** the local fluid flow process is simulated with wave propagation equations in the double-porosity medium,two porous skeletons are usually assumed,namely,host and *** them,the volume ratio of inclusion skeletons is *** previous studies have ignored the consideration of local fluid flow velocity field in inclusions,and therefore they can not completely describe the physical process of local flow oscillation and should not be applied to the situation where the fluid kinetic energy in inclusions cannot be *** this paper,we analyze the local fluid flow velocity fields inside and outside the inclusion,rewrite the kinetic energy function and dissipation function based on the double-porosity medium model containing spherical inclusions,and derive the reformulated Biot-Rayleigh(BR)equations of elastic wave propagation based on Hamilton’s *** present simulation examples with different rock and fluid *** between BR equations and reformulated BR equations show that there are significant differences in wave response ***,we compare the reformulated BR equations with the previous theories and experimental data,and the results show that the theoretical results of this paper are correct and effective.

关键词： double-porosity medium elastic wave propagation local fluid flow velocity dispersion Biot-Rayleigh equations petro-physical experiment

Optimization of antioxidant activity by response surface methodology in hydrolysates of jellyfish(Rhopilema esculentum) umbrella collagen

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Journal of Zhejiang University-Science B(Biomedicine & Biotechnology) 2009年第8期10卷 572-579页

作者： Yong-liang ZHUANG Xue ZHAO ba-fang LI College of Food Science and Engineering Ocean University of China Qingdao 266003 China

To optimize the hydrolysis conditions to prepare hydrolysates of jellyfish umbrella collagen with the highest hydroxyl radical scavenging activity, collagen extracted from jellyfish umbrella was hydrolyzed with trypsin, and response surface methodology （RSM） was applied. The optimum conditions obtained from experiments were pH 7.75, temperature （T） 48.77 ℃, and enzyme-to-substrate ratio （[E]/[S]） 3.50%. The analysis of variance in RSM showed that pH and [E]/[S] were important factors that significantly affected the process （P〈0.05 and P〈0.01, respectively）. The hydrolysates of jellyfish umbrella collagen were fractionated by high performance liquid chromatography （HPLC）, and three fractions （HF-1〉3000 Da, 1000 Da〈HF-2〈3000 Da, and HF-3〈1000 Da） were collected. The HF-2 fraction had the highest hydroxyl radical scavenging activity with the highest yield compared with the other two fractions. Furthermore, HF-2 also showed the strongest Cu^2＋-chelating ability and the best tyrosinase-inhibitory activity.

关键词： Jellyfish umbrella collagen Hydrolysis Antioxidant activity Response surface methodology (RSM)

Lower limit law of welding windows for explosive welding of dissimilar metals

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Journal of Iron and Steel Research International 2017年第8期24卷 852-857页

作者： Chang-gen Shi Xuan Yang Yu-heng Ge Jun You Hong-bao Hou PI.A University of Science and Technology Nanjing 210007JiangsuChina baicheng Ordnance Test Center Baicheng 137001JilinChina

The influence of explosive charge thickness on the quality of explosive welding of dissimilar metals was *** lower limit law should be followed in the course of explosive *** welding experiments of stainless steel（410S）and steel（Q345R）were carried out in three different kinds of explosive charge thicknesses,namely 15,25and *** of morphology and mechanical properties of three samples were observed and *** was found that micro and small wavy bonding is mainly formed for charge thickness of 15mm whose strength is the highest with minor deformation and few defects in the interface;small and middle wavy bonding are mainly formed for charge thickness of 25 mm whose strength is comparatively mediocre;big wavy bonding is mainly formed for charge thickness of 35 mm whose strength is the *** cause of high bonding strength of the micro and small wavy interface was analyzed and verified on the basis of the results of Electron Probe Micro-Analyzer（EPMA）tests of three selected samples.

关键词： Explosive welding Welding window Lower limit law Cladding plate Bonding interface

Variation of nutrient fluxes by rainfall redistribution processes in the forest canopy of an urban larch plantation in northeast China

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Journal of Forestry Research 2022年第4期33卷 1259-1269页

作者： Houcai Sheng na Guo Cunyong Ju Tijiu Cai Center for Ecological Research Northeast Forestry UniversityHarbin 150040People’s Republic of China Key Laboratory of Sustainable Forest Ecosystem Management-Ministry of Education Northeast Forestry UniversityHarbin 150040People’s Republic of China College of Food Engineering East University of HeilongjiangHarbin 150040People’s Republic of China

Atmospheric deposition(dry and wet deposition)is one of the primary sources of chemical inputs to terrestrial ecosystems and replenishes the nutrient pool in forest *** often acts as a primary transporting agent and solvent;thus,nutrient cycles in forests are closely linked to hydrological *** collected precipitation data during a growing season to explore variations in nutrient cycling and nutrient balances in the rainfall redistribution process(wet deposition)in a larch plantation in northeast *** measured nutrient(NO_(3)^(-),PO_(4)^(3−),Cl^(−),K,Ca,na,and Mg)inputs via bulk precipitation,throughfall and stemfl ow,and used a canopy budget model to estimate nutrient fl uxes via canopy *** results suggest that the average concentrations of the base cation(K,Ca,na,and Mg)showed the following order:stemfl ow>throughfall>bulk *** and stemfl ow chemistry dramatically fl uctuated over the growing season when net fl uxes(throughfall+stemfl ow—bulk precipitation)of NO−3,PO3−4,SO2−4,Cl−,K,Ca,na,and Mg were−6.676 kg·ha^(-1),−1.094 kg·ha^(-1),−2.371 kg·ha^(-1),1.975 kg·ha^(-1),0.470 kg·ha^(-1),−5.202 kg·ha^(-1),−0.336 kg·ha^(-1),and 1.397 kg·ha^(-1),*** results suggest that NO−3,PO3−4,SO2−4,Ca,and na were retained,while Cl−,K,and Mg were washed off by throughfall and stemfl ow.

关键词： Rainfall redistribution Aqueous fluxes Water chemistry Macronutrients input Plantation forest Harbin

Nonlinear Mathematical Modeling and Sensitivity Analysis of Hydraulic Drive Unit

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Chinese Journal of Mechanical Engineering 2015年第5期28卷 999-1011页

作者： KONG Xiangdong YU Bin QUAN Lingxiao ba Kaixian WU Liujie national Engineering Research Center for Local Joint of Advanced Manufacturing Technology and Equipment Yanshan University Hebei Provincial Key Laboratory of Heavy Machinery Fluid Power Transmission and Control Yanshan University School of Mechanical Engineering Yanshan University

The previous sensitivity analysis researches are not accurate enough and also have the limited reference value, because those mathematical models are relatively simple and the change of the load and the initial displacement changes of the piston are ignored, even experiment verification is not conducted. Therefore, in view of deficiencies above, a nonlinear mathematical model is established in this paper, including dynamic characteristics of servo valve, nonlinear characteristics of pressure-flow, initial displacement of servo cylinder piston and friction nonlinearity. The transfer function block diagram is built for the hydraulic drive unit closed loop position control, as well as the state equations. Through deriving the time-varying coefficient items matrix and time-varying free items matrix of sensitivity equations respectively, the expression of sensitivity equations based on the nonlinear mathematical model are obtained. According to structure parameters of hydraulic drive unit, working parameters, fluid transmission characteristics and measured friction-velocity curves, the simulation analysis of hydraulic drive unit is completed on the MATLAB/Simulink simulation platform with the displacement step 2 mm, 5 mm and 10 mm, respectively. The simulation results indicate that the developed nonlinear mathematical model is sufficient by comparing the characteristic curves of experimental step response and simulation step response under different constant load. Then, the sensitivity function time-history curves of seventeen parameters are obtained, basing on each state vector time-history curve of step response characteristic. The maximum value of displacement variation percentage and the sum of displacement variation absolute values in the sampling time are both taken as sensitivity indexes. The sensitivity indexes values above are calculated and shown visually in histograms under different working conditions, and change rules are analyzed. Then the sensitivity index

关键词： nonlinear mathematical model hydraulic drive unit valve-controlled symmetrical cylinder sensitivity analysis sensitivity index

International Szent-Gyorgyi Prize for Progress in Cancer Research:basic and translational research recognition Mary-Claire King received the 2016 Prize for her pioneering research that demonstrated the first evidence of genetic predisposition to breast cancer

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Chinese Journal of Cancer 2017年第11期36卷 533-536页

作者： Hali Hartmann Jie Zhao Sujuan ba national Foundation for Cancer Research

The Szent-Gy?rgyi Prize for Progress in Cancer Research is a prestigious scientific award sponsored by the national Foundation for Cancer Research(NFCR)-a leading cancer research charitable organization in the United States that supports innovative cancer research globally with the ultimate goal to cure cancer. The coveted Szent-Gy?rgyi Prize annually honors a scientist whose seminal discovery or body of work has resulted in, or led toward, notable contributions to cancer prevention, diagnosis, or treatment; and the discovery has had a high direct impact of saving people's lives. In addition, the prize promotes public awareness of the importance of basic cancer research and encourages the sustained investment needed to accelerate the translation of these research discoveries into new cancer treatments. In 2016, NFCR's Szent-Gy?rgyi Prize Selection Committee was unanimous in its decision to recognize an icon in human disease genetics, Dr. Mary-Claire King, for her pioneering research that demonstrated the first evidence of genetic predisposition to breast cancer. Her proof of existence of BRCA1 gene and its location has made genetic screening for breast and ovarian cancers possible, saving lives of many people who are at high risk with inherited BRCA1 mutations.

关键词： The national Foundation for Cancer Research The Szent-Gyorgyi Prize Mary-Claire King BRCA1 and genetic testing

Cracking Tendency of Restrained Concrete at Early Ages

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Journal of Wuhan University of Technology(Materials Science) 2008年第2期23卷 263-267页

作者： ba Hengjing SU Anshuang GAO Xiaojian TAO Qi School of Civil Engineering Harbin Institute of Technology Harbin 150006 China

A modified testing system characterized by full automation, steady operation and high accuracy of strain and stress measurements was developed to determine the cracking tendency of high strength concrete （HSC） in restrained condition at early ages. The shrinkage stress and the tensile creep behavior of HSC at early ages were investigated. The influence of W/C ratio and curing conditions on the early-age shrinkage stress and tensile creep was evaluated. It was found that the lower W/C ratio and drying curing condition resulted in higher shrinkage stress, stress induced tensile creep and greater cracking tendency.

关键词： cracking tendency shrinkage stress tensile creep concrete early ages

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风机叶片故障预测的振动方法研究

电力系统装备 2019年第7期 96-97页

作者：巴根那大唐新能源蒙西公司内蒙古呼和浩特010000

随着时代的发展,科学技术的发展,所有相关的领域都有了许多的进步和发展,以往许多的问题,也随着科学技术的不断发展,开始有了解决的方法,在科学技术不断发展的现在,我们已经有了很多的相关技术,来针对以往无法解决的还对整个领域造成极... 详细信息

随着时代的发展,科学技术的发展,所有相关的领域都有了许多的进步和发展,以往许多的问题,也随着科学技术的不断发展,开始有了解决的方法,在科学技术不断发展的现在,我们已经有了很多的相关技术,来针对以往无法解决的还对整个领域造成极大的负面影响的问题。风机叶片故障预测的振动方法就是其中之一,风叶的使用十分广泛,在家用的风扇,相关鼓风机,工业的吹风机,风源发动机等等,都会使用到风叶。而风叶由于内部体积较小,不容易发现问题,导致问题发生的时候,整个风机叶片所产生的故障就很难修复了,所以需要定期对风机叶片进行维修,随着科学技术的发展,这类问题随着振动方法的使用已经逐渐得到解决。本文主要阐释了风机叶片故障的问题,以及振动方法在预测风机叶片故障中的使用。

关键词：风机叶片故障预测振动方法问题研究