检索结果-南通市图书馆

在线全文

学校读者我要写书评

暂无评论

水泥砂浆在主动围压下的动态力学性能

爆炸与冲击 2008年第6期28卷 561-564页

作者：薛志刚胡时胜中国科学技术大学中国科学院材料力学行为和设计重点实验室安徽合肥230026

水泥砂浆等脆性材料的力学性能与所受围压的大小密切相关。为了研究水泥砂浆在围压下的动态力学性能,研制了适于分立式Hopkinson压杆加载的主动围压装置,最大预加载主动围压大于30 MPa。实验得到了水泥砂浆在不同围压、不同应变率下的... 详细信息

水泥砂浆等脆性材料的力学性能与所受围压的大小密切相关。为了研究水泥砂浆在围压下的动态力学性能,研制了适于分立式Hopkinson压杆加载的主动围压装置,最大预加载主动围压大于30 MPa。实验得到了水泥砂浆在不同围压、不同应变率下的轴向应力应变曲线,发现材料在围压作用下抗压强度和韧性大大提高并且整体进入了伪塑性,而材料的应变率效应也是显著的。

关键词：固体力学动态力学性能主动围压水泥砂浆霍普金森压杆

Hourglass Control in Dynamic Explicit Simulation of Cold Ring Rolling Process

在线全文

学校读者我要写书评

暂无评论

Computer Aided Drafting,Design and Manufacturing 2007年第2期17卷 37-42页

作者： ZHANG xue-bin LI zhi-gang LIU Yu-qi State Key Laboratory of Material Processes and Die ＆ Mould Technology Huazhong University of Science and Technology Wuhan 430074 China

Hourglass is remarkably aroused in ring rolling simulation with reduced integration element because of violent ring vibration and small contact area of ring with forming rollers. Hourglass energy can be reduced by improving mesh density. Combined approach of artificial damping and artificial stiffness can control the hourglass. A ring with rectangular section is simulated with the weight factor of artificial stiffness resistance set to 0.2. The artificial damping hourglass control coefficient is set to 0.1, and the artificial stiffness hourglass control coefficient is set to 0.001. The ratio of hourglass energy to internal energy is reduced to 2.5 percent. Compared with axial spread width test, the effectiveness of hourglass control in ring rolling simulation is verified.

关键词： hourglass control finite element cold ring rolling combined method

Comparison of Rotating Stall Warning by Different Methods for Variable Speed Configurations in a Contra-Rotating Compressor

在线全文

学校读者我要写书评

暂无评论

Journal of Thermal Science 2024年第4期33卷 1379-1393页

作者： xue Fei WANG Yan'gang LIU Qian WU Tong LIU Hanru School of Power and Energy Northwestern Polytechnical UniversityXi’an710072China

Stall in compressors can cause performance degradation and even lead to *** unacceptable consequences can be avoided by timely monitoring stall inception and taking effective *** paper focused on the rotating stall warning in a low-speed axial contra-rotating ***,the stall disturbance characteristics under different speed configurations were *** results showed that as the speed ratio(RR)increased,the stall disturbance propagation speed based on the rear rotor speed gradually ***,the standard deviation(SD)method,the cross-correlation(CC)method,and the discrete wavelet transform(DWT)method were employed to obtain the stall initiation moments of three different speed *** was found that the SD and CC methods did not achieve significant stall warning results in all three speed ***,the stall initiation moment obtained by the DWT method at RR=1.125 was one period after the stall had fully developed,which was ***,a stall warning method was developed in the present work based on the long short-term memory(LSTM)regression *** applying the LSTM model,the predicted stall initiation moments of three speed configurations were at the 557th,518th,and 333rd revolution,which were44,2,and 74 revolutions ahead of stall onset moments,***,in scenarios where a minor disturbance preceded the stall,the stall warning effect of the LSTM was greatly improved in comparison with the aforementioned three *** contrast,when the pressure fluctuation before the stall was relatively small,the differences between the stall initiation moments predicted by these four methods were not significant.

关键词： contra-rotating compressor stall disturbance stall initiation moment long short-term memory(LSTM) stall warning

Facile molybdenum and aluminum recovery from spent hydrogenation catalyst

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemical Engineering 2024年第5期69卷 72-78页

作者： Zhenhui Lv Jianan Li Dong xue Tao Yang gang Wang Chong Peng State Key Laboratory of Fine Chemicals School of Chemical EngineeringDalian University of TechnologyDalian 116024China Dalian Research Institute of Petroleum and Petrochemicals SINOPECDalian 116041China

Industrial catalyst waste has emerged as a hazardous pollutant that requires safe and proper disposal after the unloading *** a valuable and sustainable strategy for its treatment is a significant challenge compared to traditional *** this study,we present a facile method for the recovery of molybdenum and aluminum contents from spent Mo-Ni/Al_(2)O_(3) hydrogenation catalysts through crystallization separation and ***,the recovered molybdenum and aluminum are utilized as active metals and carriers for the preparation of new *** properties were thoroughly analyzed and investigated using various characterization *** hydrogenation activity of these newly prepared catalysts was evaluated on a fixed-bed small-scale device and compared with a reference catalyst synthesized from commercial raw ***,the hydrogenation activity of the catalysts was further assessed by using the entire distillate oil of coal liquefaction as the raw oil,specifically focusing on denitrogenation and aromatic *** work not only offers an effective solution for recycling catalysts but also promotes sustainable development.

关键词： Waste treatment Alumina Hydrogenation Catalyst Crystallization Precipitation

室内超宽带通信最大似然均衡算法的误码率性能分析

在线全文

学校读者我要写书评

暂无评论

哈尔滨工程大学学报 2007年第10期28卷 1156-1159,1170页

作者：薛志刚王石记顾学迈哈尔滨工业大学通信技术研究所黑龙江哈尔滨150001

为了分析高速率室内超宽带系统能量收集接收的误码率性能并建立相应的理论分析框架,首先要得到理想的全波形匹配和实际中的部分波形匹配下的最大似然均衡等效信号接收模型,再采用维特比算法来实现最大似然均衡.能量收集通过在接收端进... 详细信息

为了分析高速率室内超宽带系统能量收集接收的误码率性能并建立相应的理论分析框架,首先要得到理想的全波形匹配和实际中的部分波形匹配下的最大似然均衡等效信号接收模型,再采用维特比算法来实现最大似然均衡.能量收集通过在接收端进行匹配接收来实现,即采用积分窗口法收集接收信号能量.在维特比算法实现过程中需要合理设计白化滤波器参数.理论推导与仿真结果表明,可以有效消除符号间干扰影响,接近无符号间干扰的性能.该方法在抑制符号间干扰方面切实可行的.

关键词：超宽带信道模型积分窗口能量收集符号间干扰最大似然算法

Investigations of methane adsorption characteristics on marine-continental transitional shales and gas storage capacity models considering pore evolution

在线全文

学校读者我要写书评

暂无评论

Petroleum Science 2024年第4期21卷 2273-2286页

作者： Chen-gang Lu Xian-Ming Xiao Zhen-Qian xue Zhang-Xin Chen Yin-Tao Dong Yue Feng gang Li School of Energy Resources China University of Geosciences (Beijing) School of Civil and Environmental Engineering Nanyang Technological University Chemical and Petroleum Engineering University of Calgary Eastern Institute of Technology (tentative) CNOOC Research Institute

Methane adsorption is a critical assessment of the gas storage capacity(GSC) of shales with geological conditions. Although the related research of marine shales has been well-illustrated, the methane adsorption of marine-continental transitional(MCT) shales is still ambiguous. In this study, a method of combining experimental data with analytical models was used to investigate the methane adsorption characteristics and GSC of MCT shales collected from the Qinshui Basin, China. The Ono-Kondo model was used to fit the adsorption data to obtain the adsorption parameters. Subsequently, the geological model of GSC based on pore evolution was constructed using a representative shale sample with a total organic carbon(TOC) content of 1.71%, and the effects of reservoir pressure coefficient and water saturation on GSC were explored. In experimental results, compared to the composition of the MCT shale, the pore structure dominates the methane adsorption, and meanwhile, the maturity mainly governs the pore structure. Besides, maturity in the middle-eastern region of the Qinshui Basin shows a strong positive correlation with burial depth. The two parameters, micropore pore volume and non-micropore surface area, induce a good fit for the adsorption capacity data of the shale. In simulation results, the depth,pressure coefficient, and water saturation of the shale all affect the GSC. It demonstrates a promising shale gas potential of the MCT shale in a deeper block, especially with low water saturation. Specifically,the economic feasibility of shale gas could be a major consideration for the shale with a depth of 60% in the Yushe-Wuxiang area. This study provides a valuable reference for the reservoir evaluation and favorable block search of MCT shale gas.

关键词： High-pressure methane adsorption Marine-continental transitional shale gas Ono-Kondo model Adsorption thermodynamics Gas storage capacity model

Design of weak current measurement system and research on temperature impact

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Nuclear Science and Techniques 2024年第4期35卷 46-56页

作者： Chu-Xiang Zhao San-gang Li Rong-Rong Su Li Yang Ming-Zhe Liu Qing-Yue xue Shan Liao zhi Zhou Qing-Shan Tan Xian-Guo Tuo Yi Cheng College of Nuclear Technology and Automation Engineering Chengdu University of Technology1#DongsanluErxianqiaoChengdu 610059China Applied Nuclear Technology in Geosciences Key Laboratory of Sichuan Province Chengdu University of Technology1#DongsanluErxianqiaoChengdu 610059China University of Science and Technology of China Hefei 230026China School of Physics and Electronic Engineering Sichuan University of Science and EngineeringZigong 643000China

A dedicated weak current measurement system was designed to measure the weak currents generated by the neutron ionization *** system incorporates a second-order low-pass filter circuit and the Kalman filtering algorithm to effectively filter out noise and minimize interference in the measurement *** conducted under normal temperature conditions has demonstrated the system's high precision ***,it was observed that temperature variations can affect the measurement *** were collected across temperatures ranging from -20 to 70℃,and a temperature correction model was established through linear regression fitting to address this *** feasibility of the temperature correction model was confirmed at temperatures of -5 and 40℃,where relative errors remained below 0.1% after applying the temperature *** research indicates that the designed measurement system exhibits excellent temperature adaptability and high precision,making it particularly suitable for measuring weak currents.

关键词： Weak current measurement system Neutron ionization chamber Kalman filter algorithm Temperature correction model

Research on a TOPSIS energy efficiency evaluation system for crude oil gathering and transportation systems based on a GA-BP neural network

在线全文

学校读者我要写书评

暂无评论

Petroleum Science 2024年第1期21卷 621-640页

作者： xue-Qiang Zhang Qing-Lin Cheng Wei Sun Yi Zhao zhi-Min Li Key Lab of Ministry of Education for Enhancing the Oil and Gas Recovery Ratio Northeast Petroleum UniversityDaqing163318HeilongjiangChina China Petroleum Pipeline Material and Equipment Co. LtdLangfang065000HebeiChina Research Institute of Petroleum Engineering and Technology Sinopec Northwest Oilfield CompanyUrumqi830011XinjiangChina

As the main link of ground engineering,crude oil gathering and transportation systems require huge energy consumption and complex *** is necessary to establish an energy efficiency evaluation system for crude oil gathering and transportation systems and identify the energy efficiency *** this paper,the energy efficiency evaluation system of the crude oil gathering and transportation system in an oilfield in western China is *** with the big data analysis method,the GA-BP neural network is used to establish the energy efficiency index prediction model for crude oil gathering and transportation *** comprehensive energy consumption,gas consumption,power consumption,energy utilization rate,heat utilization rate,and power utilization rate of crude oil gathering and transportation systems are *** the efficiency and unit consumption index of the crude oil gathering and transportation system,the energy efficiency evaluation system of the crude oil gathering and transportation system is established based on a game theory combined weighting method and TOPSIS evaluation method,and the subjective weight is determined by the triangular fuzzy analytic hierarchy *** entropy weight method determines the objective weight,and the combined weight of game theory combines subjectivity with objectivity to comprehensively evaluate the comprehensive energy efficiency of crude oil gathering and transportation systems and their ***,the weak links in energy utilization are identified,and energy conservation and consumption reduction are *** above research provides technical support for the green,efficient and intelligent development of crude oil gathering and transportation systems.

关键词： Crude oil gathering and transportation system GA-BP neural network Energy efficiency evaluation TOPSIS evaluation method Energy saving and consumption reduction

Surviving winter on the Qinghai-Xizang Plateau:Extensive reversible protein phosphorylation plays a dominant role in regulating hypometabolism in hibernating Nanorana parkeri

在线全文

学校读者我要写书评

暂无评论

Zoological Research 2024年第1期45卷 1-12页

作者： Yong-gang Niu Deng-Bang Wei xue-Jing Zhang Ti-Sen Xu Xiang-Yong Li Hai-Ying Zhang zhi-Fang An Kenneth B.Storey Qiang Chen Department of Life Sciences Dezhou UniversityDezhouShandong 253023China State Key Laboratory of Plateau Ecology and Agriculture Qinghai UniversityXiningQinghai 810016China School of Life Sciences Lanzhou UniversityLanzhouGansu 730000China Department of Biology Carleton UniversityOttawaON K1S 5B6Canada

Changes in protein abundance and reversible protein phosphorylation(RPP)play important roles in regulating hypometabolism but have never been documented in overwintering frogs at high *** test the hypothesis that protein abundance and phosphorylation change in response to winter hibernation,we conducted a comprehensive and quantitative proteomic and phosphoproteomic analysis of the liver of the Xizang plateau frog,Nanorana parkeri,living on the Qinghai-Xizang *** total,5170 proteins and 5695 phosphorylation sites in 1938 proteins were *** on proteomic analysis,674 differentially expressed proteins(438 up-regulated,236 down-regulated)were screened in hibernating *** versus summer *** enrichment analysis revealed that higher expressed proteins in winter were significantly enriched in immune-related signaling pathways,whereas lower expressed proteins were mainly involved in metabolic processes.A total of 4251 modified sites(4147 up-regulated,104 down-regulated)belonging to 1638 phosphoproteins(1555 up-regulated,83 down-regulated)were significantly changed in the *** hibernation,RPP regulated a diverse array of proteins involved in multiple functions,including metabolic enzymatic activity,ion transport,protein turnover,signal transduction,and alternative *** changes contribute to enhancing protection,suppressing energy-consuming processes,and inducing metabolic ***,the activities of phosphofructokinase,glutamate dehydrogenase,and ATPase were all significantly lower in winter compared to *** conclusion,our results support the hypothesis and demonstrate the importance of RPP as a regulatory mechanism when animals transition into a hypometabolic state.

关键词： Nanorana parkeri Proteomic Phosphoproteomic Hibernation Reversible protein phosphorylation Metabolism