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Auto-parametric resonance of a continuous-beam-bridge model under two-point periodic excitation:an experimental investigation and stability analysis

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Earthquake Engineering and Engineering Vibration 2024年第2期23卷 445-454页

作者： li Yuchun Shen Chao liu wei li Dong Department of Hydraulic Engineering College of Civil EngineeringTongji UniversityShanghai 200092China

The auto-parametric resonance of a continuous-beam bridge model subjected to a two-point periodic excitation is experimentally and numerically investigated in this *** auto-parametric resonance experiment of the test model is conducted to observe and measure the auto-parametric resonance of a continuous beam under a two-point excitation on *** parametric vibration equation is established for the test model using the finite-element *** auto-parametric resonance stability of the structure is analyzed by using Newmark's method and the energy-growth exponent *** effects of the phase difference of the two-point excitation on the stability boundaries of auto-parametric resonance are studied for the test *** with the experiment,the numerical instability predictions of auto-parametric resonance are consistent with the test phenomena,and the numerical stability boundaries of auto-parametric resonance agree with the experimental *** a continuous beam bridge,when the ratio of multipoint excitation frequency(applied to the columns)to natural frequency of the continuous girder is approximately equal to 2,the continuous beam may undergo a strong auto-parametric *** with the present experiment and analysis,a hypothesis of Volgograd Bridge's serpentine vibration is discussed.

关键词： auto-parametric resonance continuous beam bridge model two-point excitation experimental investigation stability analysis vibration of Volgograd Bridge

Non-Convex Optimization of Resource Allocation in Fog Computing Using Successive Approximation

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Journal of Systems Science & Complexity 2024年第2期37卷 805-840页

作者： li Shiyong liu Huan li Wenzhe SUN wei School of Economics and Management Yanshan UniversityQinhuangdao 066000China

Fog computing can deliver low delay and advanced IT services to end users with substantially reduced energy ***,with soaring demands for resource service and the limited capability of fog nodes,how to allocate and manage fog computing resources properly and stably has become the ***,the paper investigates the utility optimization-based resource allocation problem between fog nodes and end users in fog *** authors first introduce four types of utility functions due to the diverse tasks executed by end users and build the resource allocation model aiming at utility ***,for only the elastic tasks,the convex optimization method is applied to obtain the optimal results;for the elastic and inelastic tasks,with the assistance of Jensen’s inequality,the primal non-convex model is approximated to a sequence of equivalent convex optimization problems using successive approximation ***,a two-layer algorithm is proposed that globally converges to an optimal solution of the original ***,numerical simulation results demonstrate its superior performance and *** with other works,the authors emphasize the analysis for non-convex optimization problems and the diversity of tasks in fog computing resource allocation.

关键词： Fog computing non-convex optimization optimal resource allocation successive approximation method utility function

VKORC1 genotypes are associated with response to warfarin but free warfarin concentration during initial anticoagulation in healthy Chinese volunteers

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Chinese Medical Journal 2009年第18期122卷 2117-2122页

作者： XIE Shuang liu Hong TIAN Lei JIANG Juan-juan CHEN Guo-liang liu li-wei XU li li Yi-shi Key Laboratory of Clinical Trial Research in Cardiovascular Drugs Ministry of Health Fu Wai Hospital Chinese Academy of Medical Sciences Beijing 100037 China Peking Union Medical College Chinese Academy of Medical Sciences Beijing 100037 China

Background The genetic variations in VKORC1 modulate the stable responses to warfarin administration. But the role of VKORC1 polymorphisms during the initial anticoagulation and elimination period in the Hart Chinese population is not clear. Methods Twenty-four healthy Chinese volunteers were grouped according to their VKORC1 genotype. Twelve subjects were in the 3 mg group and 12 in the 6 mg group. VKORC1 genotypes were determined by a polymerase chain reaction （PCR） based restriction fragment length polymorphism （RFLP） assay and sequencing. The international normalized ratio （INR） was measured with an ACL9000 coagulation analyser. Plasma free warfarin concentration was measured with LC/MS/MS. Results In the initial anticoagulation period, the -1639AG and 1173TC carriers compared with the -1639AA and 1173TT carriers had a low INR value. The differences between genotypes with regard to INR values were more obvious in the 3 mg subjects （P 〈0.05）, and were not significantly different among the 6 mg subjects （P〉0.05）. On the contrary, no significant difference of plasma free warfarin concentration between genotypes was observed in each dosage group. It took 96 hours for the INR value and 144 hours for the free warfarin plasma concentration to come back to baselines after the last dose. No significant difference among genotypes and dosing groups was detected in the elimination phase （P〉0.05）. Conclusion VKORC1 polymorphisms are associated with differences in the initial response to warfarin when given at fixed doses, without affecting, as expected, its plasma concentration.

关键词： warfarin VKORC1 genotype international normalized ratio free warfarin plasma concentration

Transient Monte Carlo simulation of phonon transport in silicon nanofilms with the local heat source

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Science China(Technological Sciences) 2024年第7期67卷 2087-2098页

作者： li JiaQi CAI JiuQing li Rui liu ZhiChun liu wei School of Energy and Power Engineering Huazhong University of Science and TechnologyWuhan 430074China Wuhan Second Ship Design and Research Institute Wuhan 430205China

Accurate prediction of junction temperature is crucial for the efficient thermal design of silicon nano-devices. In nano-scale semiconductor devices, significant ballistic effects occur due to the mean free path of phonons comparable to the heat source size and device scale. We employ a three-dimensional non-gray Monte Carlo simulation to investigate the transient heat conduction of silicon nanofilms with both single and multiple heat sources. The accuracy of the present method is first verified in the ballistic and diffusion limits. When a single local heat source is present, the width of the heat source has a significant impact on heat conduction in the domain. Notably, there is a substantial temperature jump at the boundary when the heat source width is 10 *** increasing heat source width, the boundary temperature jump weakens. Furthermore, we observe that the temperature excitation rate is independent of the heat source width, while the temperature influence range expands simultaneously with the increase in heat source width. Around 500 ps, the temperature and heat flux distribution in the domain stabilize. In the case of dual heat sources, the hot zone is broader than that of a single heat source, and the temperature of the hot spot decreases as the heat source spacing increases. However, the mean heat flux remains unaffected. Upon reaching a spacing of 200 nm between the heat sources, the peak temperature in the domain remains unchanged once a steady state is reached. These findings hold significant implications for the thermal design of silicon nano-devices with local heat sources.

关键词： phonon transport Monte Carlo simulation transient heat conduction silicon nanofilms local heat source

Estimates on Blow-up Rate of Nonlinear Parabolic Systems with Nonlinear Boundary Conditions

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Chinese Quarterly Journal of Mathematics 2005年第4期20卷 401-405页

作者： liu wei-ling li Guo-fu Department of Mathematics Zhengzhou Teacher＇s College Zhengzhou 450044 China

In this paper, the estimate on blow-up rate of the following nonlinear parabolic system is considered：{ut=uxx＋u^l 11v^l 12,vt=vxx＋u^l21v^l22,（x,t）∈（0,1）×（0,T）,ux（0,t）=0,vx（0,t）=0,t∈（0,T）,ux（1,t）=（u^p11v^p12）（1,t）,vx（1,t）=（u^p21v^p22）（1,t）,t∈（0,T）,u（x,0）=u0（x）,v（x,0）=v0（x）,x∈（0,1）We will prove that there exist two positive constants such that：c≤max x∈[0,1]u（x,t）（T-t）^r（l1-1）≤C,0〈t〈T,c≤max x∈[0,1] v（x,t）（T-t）^1/（t1-1）≤C,0〈t〈*** l1=l21α/α2＋l22,r=α1/α2〉1,α1≤α2〈0.

关键词： nonlinear boundary condition nonlinear parabolic system blow-up rate

Effect of sorbed and desorbed Zn(Ⅱ) on the growth of a green alga (Chlorella pyrenoidosa)

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Journal of Environmental Sciences 2007年第9期19卷 1028-1031页

作者： CHANG Guo-hua CHEN Hao CHEN Hai-liu li wei PAN Gang State Key Laboratory of Environmental Aquatic Chemistry Research Center for Eco-Environmental Sciences Chinese Academy of Sciences Beijing 100085 China

Toxic effect of Zn（II） on a green alga （Chlorella pyrenoidosa） in the presence of sepiolite and kaolinite was investigated. The Zn-free clays were found to have a negative impact on the growth of C. pyrenoidosa in comparison with control samples （without adding any clay or Zn（II））. When Zn（II） was added, the algae in the presence of clays could be better survived than the control samples, which was actually caused by a decrease in Zn（II） concentration in the solution owing to the adsorption of Zn（II） on the clays. When the solution system was diluted, the growth of algae could be further inhibited as compared to that in a system which had the same initial Zn（II） concentration as in the diluted system. This in fact resulted from desorption of Zn（II） from the zinc-contaminated clays, although the effect varied according to the different desorption capabilities of sepiolite and kaolinite. Therefore the adsorption and desorption processes of Zn（H） played an important part in its toxicity, and adsorption and desorption of pollutants on soils/sediments should be well considered in natural eco-environmental systems before their risk of toxicity to aquatic organisms was assessed objectively.

关键词： Chlorella pyrenoidosa clays adsorption and desorption toxicity

Common causes of geriatric medical emergencies in China

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Journal of Geriatric Cardiology 2015年第1期12卷 91-92页

作者： Hong-wei liu li-Na Han Yue-Xiang Zhao wei Zhang Department of Cardiovascular Disease South Building of PLA General Hospital Beijing 100853 China.

To the Editor One of the most significant demographic changes in our cotmtry is the increase in the elderly population. In China Mainland, the population aged 60 and older was 194 million in 2012, accounting for 14.3% of the total population. However, by 2053, it is estimated that the number of elderly will reach 487 million, representing 34.8% of the total population. Elderly patients represent an everncreasing populace in emergency medicine who often present with atypical signs and symptoms as well as eomorbidities that can complicate diagnoses and *** The geographic factors and the developmental status of the country can influence the spectrum of common geriatric emergencies. Thus, this study presents a retrospective analysis of common causes of geriatric emergencies involving 9,628 elderly patients from Jan. 2008 to Dec. 2013 in an emergency department in Beijing, China.

关键词： China Comorbidity Emergency medicine The elderly

胆管损伤对PD-1抑制剂相关肝损伤临床病理特征影响分析

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肝脏 2024年第8期29卷 965-970页

作者：王艳刘立伟赵梦鱼陈炜赵新颜首都医科大学附属北京友谊医院肝病中心国家消化系统疾病临床医学研究中心首都医科大学附属北京佑安医院肝病四科首都医科大学附属北京友谊医院消化内科国家消化系统疾病临床医学研究中心

目的探索PD-1抑制剂相关的免疫介导肝损伤临床特征。方法回顾分析2016年4月—2022年12月首都医科大学附属北京友谊医院住院的使用PD-1抑制剂且出现免疫介导肝损伤的恶性肿瘤患者。根据血清碱性磷酸酶水平，分为CTCAE 0级、1级、2级、... 详细信息

目的探索PD-1抑制剂相关的免疫介导肝损伤临床特征。方法回顾分析2016年4月—2022年12月首都医科大学附属北京友谊医院住院的使用PD-1抑制剂且出现免疫介导肝损伤的恶性肿瘤患者。根据血清碱性磷酸酶水平，分为CTCAE 0级、1级、2级、3级。比较上述各组患者的临床表现、影像及病理表现。连续变量采用ANOVA检验或非参数检验，分类变量采用卡方检验，多重比较采用Bonferroni校正，P<0.05为差异有统计学意义。结果共纳入42例出现免疫介导肝损伤。根据CTCAE中ALP分级标准，有13例免疫介导肝损伤患者符合CTCAE 0级，14例1级，8例2级，7例3级。4个组间，肝损伤后CTCAE 3级患者血清胆红素明显高于CTCAE 0～2级患者分别为24.5 (17.2, 47.1)、25.5 (17.2, 65.5)、21.3 (19.6, 263.8)和153.0 (43.0, 525.3)μmol/L,P=0.036]。3例患者腹部CT或MRI出现胆道系统的信号改变：包括胆囊壁增厚水肿、肝外胆管不均匀狭窄及扩张等。有2例病例有肝穿刺活检，病理可见胆管增生、胆管上皮排列不整、汇管区间质疏松水肿等胆管损伤表现。结论超过50%的PD-1相关肝损伤患者可出现胆管酶升高，提示有胆管受损；部分患者可出现胆道系统受累的影像学表现；肝脏病理对发现小胆管炎症及破坏受损有意义。

关键词：免疫检查点抑制剂免疫介导胆管损伤碱性磷酸酶常见不良反应分级5.0

来源：博看期刊

Input-to-State Stability of Impulsive Switched Systems Involving Uncertain Impulse-Switching Moments

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IEEE/CAA Journal of Automatica Sinica 2024年第6期11卷 1515-1517页

作者： Chang liu Wenlu liu Tengda wei Xiaodi li School of Mathematical and Statistics Shandong Normal UniversityJinan 250014China

Dear Editor,This letter studies the input-to-state stability(ISS)for a class of impulsive switched systems,where uncertain impulse-switching moments are *** robustness of ISS with respect to the perturbations of the occurrence time of impulse-switching moments is revealed by several less conservative dwell-time conditions for the uncertain impulse-switching moments combined with Lyapunov ***,the Lyapunov conditions have multiple coefficients at discrete time so as to handle the hybrid effect of impulse-switching moments,and the case that time derivative of Lyapunov function is indefinite is also taken into ***,a numerical example is proposed to illustrate the effectiveness of the theoretical results.

关键词： letter conservative derivative