检索结果-南通市图书馆

Numerical analysis of uncertain temperature field by stochastic finite difference method

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(Physics,Mechanics & Astronomy) 2014年第4期57卷 698-707页

作者： WANG Chong qiu ZhiPing WU di School of Aeronautic Science and Engineering Beihang University China Academy of Launch Vehicle Technology

Based on the combination of stochastic mathematics and conventional finite difference method,a new numerical computing technique named stochastic finite difference for solving heat conduction problems with random physical parameters,initial and boundary conditions is *** with the analysis of steady-state heat conduction problems,difference discrete equations with random parameters are established,and then the computing formulas for the mean value and variance of temperature field are derived by the second-order stochastic parameter perturbation ***,the proposed random model and method are extended to the field of transient heat conduction and the new analysis theory of stability applicable to stochastic difference schemes is *** layer-by-layer recursive equations for the first two probabilistic moments of the transient temperature field at different time points are quickly obtained and easily solved by ***,by comparing the results with traditional Monte Carlo simulation,two numerical examples are given to demonstrate the feasibility and effectiveness of the presented method for solving both steady-state and transient heat conduction problems.

关键词： heat conduction uncertainty stochastic finite difference parameter perturbation stability

法压式冲泡对海南罗布斯塔咖啡感官品质的影响

在线全文

学校读者我要写书评

暂无评论

食品科学 2025年第1期46卷 108-120页

作者：刘迪劳菲董文江于鑫欣中国农业大学食品科学与营养工程学院国家果蔬加工工程技术研究中心农业农村部果蔬加工重点实验室北京市食品非热加工重点实验室北京100083 中国热带农业科学院香料饮料研究所海南万宁571533 海南省特色热带作物适宜性加工与品质控制重点实验室国家重要热带作物工程技术研究中心海南万宁571533

以中度烘焙海南罗布斯塔咖啡为研究对象,制备可溶性固形物质量分数为2%的法压式咖啡,采用喜好度评价对4种冲泡参数进行单因素和响应面试验优化,通过感官定量描述分析结合气相色谱-质谱联用法、超高效液相色谱法挖掘咖啡喜好度与其感官... 详细信息

以中度烘焙海南罗布斯塔咖啡为研究对象,制备可溶性固形物质量分数为2%的法压式咖啡,采用喜好度评价对4种冲泡参数进行单因素和响应面试验优化,通过感官定量描述分析结合气相色谱-质谱联用法、超高效液相色谱法挖掘咖啡喜好度与其感官特性及风味物质之间的相关性信息。结果表明,咖啡萃取质量浓度会随着咖啡粒径减小、粉水比增加、冲泡水温升高或冲泡时间延长而显著增大(P<0.05)。咖啡喜好度(0~6分,七点法)在粉水比1∶5(m/m)、研磨度8、冲泡水温92℃、冲泡6min时达到最高(3.3±1.6)。咖啡中共检测出78种挥发性成分,通过气味活性值分析得大马士酮、3-乙基-2,5-甲基吡嗪等关键香气化合物10种。Pearson相关性分析表明,喜好度与咖啡的圆润感、巧克力香属性呈正相关,与咖啡因、具有丁香味和酚味的4-乙基愈创木酚、4-乙烯基愈创木酚及具有粪臭味的3-甲基吲哚呈负相关。本研究能为挖掘海南罗布斯塔咖啡的风味喜好及其物质基础提供一定理论依据。

关键词：罗布斯塔咖啡冲泡参数感官定量描述分析气相色谱-质谱联用 Pearson相关性

Hot deformation behavior and microstructure features of FeCrAl-ODS alloy

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2022年第9期29卷 1455-1463页

作者： di-jun Long Shao-yu qiu Wen-bo liu Yong-duo Sun Wei Luo Hui-qun liu Rui-qian Zhang Nuclear Power Institute of China Chengdu 610213SichuanChina School of Materials Science and Engineering Central South UniversityChangsha 410083HunanChina

The hot deformation behavior of FeCrAl-ODS alloys at temperatures of 1050-1200℃ and strain rates of 0.001-1 s^(-1),*** peak stress of FeCrAl-ODS alloy during hot deformation decreased with increasing temperature and decreasing strain *** addition,the stress-strain curves show a dynamic softening phenomenon according to the shape of the flow *** on the Arrhenius-type model,a constitutive equation and processing map of FeCrAl-ODS alloy were ***,we proposed optimum processing parameters of 1200℃ and 0.001 s^(-1)based on the processing *** with FeCrAl alloys,there was no significant phenomenon of grain coarsening during hot deformation in FeCrAl-ODS *** the electron backscattered diffraction images,both recrystallized and recovered grains were observed in the matrix under dfferent deformation *** fraction of dynamically recrystallized grains in the matrix under the deformation of 1100 C/0.001 s^(-1)(42.5%)was significantly higher than that at 1200℃/0.001 s^(-1)(10.6%),which was consistent with the stress-strain curves.

关键词： FeCrAl-ODS steel Oxide dispersion strengthening High-temperature deformation Processing map

A copper-iodide cluster microcube-based X-ray scintillator

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Light(Science & Applications) 2023年第11期12卷 2261-2263页

作者： Jian qiu Xiaogang liu Joint School of the National University of Singapore and Tianjin University International Campus of Tianjin UniversityBinhai New City350207 FuzhouChina Department of Chemistry National University of SingaporeSingapore 117543Singapore Institute of Materials Research and Engineering Agency for ScienceTechnology and ResearchSingapore 138634Singapore

Newly developed copper-iodide cluster microcubes offer a solution to the issues commonly faced by powder scintillation *** problems include inadequate scintillation performance and significant light scattering,resulting in poor image *** the advent of monodisperse copper-iodide cluster microparticle scintillators,efficient and long-term stable scintillation is achieved,while ensuring ***,they enable highresolution static and dynamic X-ray imaging,providing high image quality.

关键词： cluster copper disperse

Atomic design of carbon-based dual-metal site catalysts for energy applications

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Nano Research 2023年第5期16卷 6477-6506页

作者： Huishan Shang di liu School of Chemical Engineering Zhengzhou UniversityZhengzhou 450001China Department of Chemistry Tsinghua UniversityBeijing 100084China

Carbon-based dual-metal sites catalysts(DMSCs)have emerged as a new frontier in the field of sustainable energy due to their unique coordination environments,electronic structure,the maximized atom *** reasonable utilization of carbonbased DMSCs provides new possibilities to achieve the outstanding catalytic performance,remarkable selectivity,recyclability in energy-related *** on this,this review intends to summarize the recent breakthroughs in carbonbased DMSCs for the energy ***,the definition and classifications of DMSCs are proposed,mainly dividing into three types(isolated dual-metal site pairs,binuclear homologous dual-metal sites pairs,binuclear heterologous dual-metal sites pairs).Subsequently,we discuss the potential of DMSCs targeting on energy conversion reactions,such as electrocatalytic hydrogen evolution reaction(HER),oxygen evolution reaction(OER),oxygen reduction reaction(ORR),CO_(2)reduction reaction(CO_(2)RR),N_(2) reduction reaction(NRR).Finally,we predict the remaining challenges and possible opportunities on the unique carbon-based DMSCs for energy applications in the future.

关键词： dual-metal site catalysts carbon atomic design energy applications

马铃薯淀粉同步糖化发酵制备L-乳酸条件的统计学优化

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

生物加工过程 2010年第4期8卷 6-11页

作者：赵国振熊向峰陈朝银葛锋刘迪秋韩本勇昆明理工大学生命科学与技术学院昆明650224

以马铃薯淀粉为原料,采用同步糖化发酵方法制备乳酸。通过Plackett-Burman实验设计对影响乳酸产量的7个因子进行筛选,结果表明淀粉质量浓度、糖化酶用量和发酵温度3个因素对乳酸产量影响显著。利用最陡爬坡试验逼近最大响应区,采用中心... 详细信息

以马铃薯淀粉为原料,采用同步糖化发酵方法制备乳酸。通过Plackett-Burman实验设计对影响乳酸产量的7个因子进行筛选,结果表明淀粉质量浓度、糖化酶用量和发酵温度3个因素对乳酸产量影响显著。利用最陡爬坡试验逼近最大响应区,采用中心复合实验设计及响应面分析法进行回归分析,建立影响乳酸产量的二次模型。模型求解得出最优淀粉质量浓度为271.89g/L,糖化酶用量为265.09U/g,发酵温度为39.05℃,最大理论乳酸产量为196.99g/L。3批验证实验结果平均值与预测值接近,表明该模型与实际情况拟合良好,实际最大乳酸产量为193.6g/L,较优化前提高了13.9%,L-乳酸的平均纯度达到95.2%。

关键词：发酵 L-乳酸马铃薯淀粉同步糖化发酵

Strong convergence rate of principle of averaging for jump-diffusion processes

在线全文

学校读者我要写书评

暂无评论

Frontiers of Mathematics in China 2012年第2期7卷 305-320页

作者： di liu Department of Mathematics Michigan State University East Lansing MI 48824 USA

We study jump-diffusion processes with two well-separated time scales. It is proved that the rate of strong convergence to the averaged effective dynamics is of order O（ε1/2）, where s 〈〈 1 is the parameter measuring the disparity of the time scales in the system. The convergence rate is shown to be optimal through examples. The result sheds light on the designing of efficient numerical methods for multiscale stochastic ,dynamics.

关键词： Stochastic differential equation time scale separation averaging ofperturbations

Resolving the developmental mechanisms of cardiac microthrombosis of SARS-CoV-2 based on single-cell transcriptome analysis

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 Life Sciences 2025年第1期 103-115页

作者： Xizi Luo Nan Zhang Yuntao liu Beibei Du Xuan Wang Tianxu Zhao Bingqiang liu Shishun Zhao Jiazhang qiu Guoqing Wang State Key Laboratory for diagnosis and Treatment of Severe Zoonotic Infectious diseases Key Laboratory for Zoonosis Research of the Ministry of EducationCollege of Basic MedicineJilin University State Key Laboratory for diagnosis and Treatment of Severe Zoonotic Infectious diseases Key Laboratory for Zoonosis Research of the Ministry of EducationCollege of Veterinary MedicineJilin University College of Mathematics Jilin University Bioinformatic Lab School of MathematicsShandong University Department of Cardiology China-Japan Union HospitalJilin University

The coronavirus disease 2019（COVID-19） outbreak caused by the severe acute respiratory syndrome coronavirus-2（SARS-CoV-2） developed into a global health emergency. Systemic microthrombus caused by SARS-CoV-2 infection is a common complication in patients with COVID-19. Cardiac microthrombosis as a complication of SARS-CoV-2 infection is the primary cause of cardiac injury and death in patietns with severe COVID-19. In this study, we performed single-cell sequencing analysis of the right ventricular free wall tissue from healthy donors,patients who died during the hypercoagulable period of characteristic coagulation abnormality（CAC）, and patients who died during the fibrinolytic period of CAC. We collected 61,187 cells enriched in 24 immune cell subsets and 13 cardiac-resident cell subsets. We found that in the course of SARS-CoV-2 infected heart microthrombus, MYO1EhighRASGEF1Bhighmonocyte-derived macrophages promoted hyperactivation of the immune system and initiated the extrinsic coagulation pathway by activating chemokines CCL3, CCL5. This series of events is the main cause of cardiac microthrombi following SARS-CoV-2 infection. In a SARS-CoV-2 infected heart microthrombus, excessive immune activation is accompanied by an increase in cellular iron content, which in turn promotes oxidative stress and intensifies intercellular competition. This induces cells to alter their metabolic environment, resulting in increased sugar uptake via the glycosaminoglycan synthesis pathway. In addition, high levels of reactive oxygen species generated by elevated iron levels promote increased endogenous malondialdehyde synthesis in a subpopulation of cardiac endothelial cells. This exacerbates endothelial cell dysfunction and exacerbates the coagulopathy process.

关键词：

同方期刊数据库

A novel optimal data fusion algorithm and its application for the integrated navigation system of missile

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2022年第5期35卷 53-68页

作者： di liu Xiyuan CHEN Xiao liu Key Laboratory of Micro-Inertial Instrument and Advanced Navigation Technology Ministry of Education School of Instrument Science and EngineeringSoutheast UniversityNanjing 210096China School of Electronic and Information Engineering(Department of Physics) Qilu University of TechnologyJinan 250353China

For Inertial Navigation System(INS)/Celestial Navigation System(CNS)/Global Navigation Satellite System(GNSS)integrated navigation system of the missile,the performance of data fusion algorithms based on the Cubature Kalman Filter(CKF)is seriously degraded when there are non-Gaussian noise and process-modeling errors in the system ***,a novel method is proposed,which is called Optimal Data Fusion algorithm based on the Adaptive Fading maximum Correntropy generalized high-degree CKF(AFCCKF-ODF).First,the Adaptive Fading maximum Correntropy generalized high-degree CKF(AFCCKF)is proposed and used as the local filter for the INS/GNSS and INS/CNS subsystems to improve the robustness of local state ***,the local state estimation is fused based on the minimum variance principle and highdegree cubature criterion to get the globally optimal ***,the experimental results verify that the proposed algorithm can significantly improve the robustness of the missile-borne INS/CNS/GNSS integrated navigation system to non-Gaussian noise and process modeling error and obtain the global optimal navigation information.

关键词： Data fusion High-degree cubature Kalman filter Integrated navigation Non-Gaussian noise Process-modeling error