检索结果-内蒙古大学图书馆

rate-dependent constitutive modelling blasting crack initiation and propagation in rock masses

国际煤炭科学技术学报（英文版） 2023年第6期10卷 102-119页

作者： Yongjun Zhang Meng Xu Sijia Liu Fei Liu Qingsong Wang School of Civil Engineering Qingdao University of TechnologyQingdao 266033China School of Civil Engineering Qingdao University of TechnologyQingdao 266033China China State Construction Engineering Corporation International Construction CO. LTD.Suzhou 215011China CRCC Plateau Tunnel Construction Technology and Equipment R&D Center China Railway 20th Bureau Group CorporationXi'an 710016China

This study examines the fracture mechanism of cracks and the final blasting effects on defective rock masses under blasting *** failure processes of jointed rock with two prefabricated joints are investigated through numerical simulations using a two-dimensional finite element ***,simulations are performed to analyze the blasting of granite specimens with various joint arrangements,focusing on the influence of front joint length,inclination angle,and blast hole distance on failure patterns,displacement,velocity,and stress at the joint *** numerical results provide a compre-hensive summary of various typical failure modes near blast holes and joints for the first ***,the simulation successfully captures the characteristics of the ring crack zone,wing cracks,and main crack deflection affected by the front ***,the results highlight the shielding effect of the front joint,which enhances damage in the medium between the borehole and the joint while exhibiting the opposite effect behind the joint in terms of stress wave ***,this study offers objective insights into the mechanics and failure characteristics of jointed rock masses under blasting loads and serves as a valuable reference for the design and optimization of blasting operations.

关键词： Blasting failure rHT model double-jointed granite specimen dynamic crack propagation Stress wave spreading

来源：评论

学校读者我要写书评

暂无评论

Study on the Fluid-Solid coupling Seepage of the deep Tight reservoir Based on 3d digital core Modeling

引用

Energy engineering 2025年第2期122卷 537-560页

作者： Haijun Yang Zhenzhong Cai Hui Zhang Chong Sun Jing Li Xiaoyu Meng Chen Liu Chengqiang Yang PetroChina Tarim Oilfield Company Korla841000China CNPC R&D Center for Ultra-Deep Complex Reservoir Exploration and Development Korla841000China National Key Laboratory of Deep Oil and Gas China University of Petroleum(East China)Qingdao266580China Structure and Shipping Department Offshore Oil Engineering(Qingdao)Co.Ltd.Qingdao266520China

deep tight reservoirs exhibit complex stress and seepage fields due to varying pore structures,thus the seepage characteristics are significant for enhancing oil *** study conducted triaxial compression and permeability tests to investigate the mechanical and seepage properties of tight sandstone.A digital core of tight sandstone was built using computed Tomography(CT)scanning,which was divided into matrix and pore phases by a pore equivalent diameter threshold.A fluid-solid coupling model was established to investigate the seepage characteristics at *** results showed that increasing the confining pressure decreased porosity,permeability,and flow velocity,with the pore phase becoming the dominant seepage *** and large pores closed first under increasing pressure,resulted in a steep drop in ***,permeability slightly decreased under high confining pressure,which followed a first-order exponential *** velocity increased with seepage *** the damage mainly occurred in stress-concentration regions under low seepage *** behavior followed linear darcy flow,the damage emerged at seepage entrances under high pressure,which decreased rock elastic modulus and significantly increased permeability.

关键词： digital core fluid-solid coupling pore structure microscopic seepage

来源：评论

学校读者我要写书评

暂无评论

Sulfation of the extracellular polysaccharide from the edible fungus Stropharia rugosoannulata with its antioxidant activity

引用

Journal of Future Foods 2023年第1期3卷 37-42页

作者： Hui Hao Chun Cui Yuqing Xing Xuewei Jia Bingjie Ma Wenyi Kang Tianxiao Li Mingqi Gao Chunping Xu China Tobacco Henan Industry Co.Ltd. Zhengzhou 450000China College of Food and Biological Engineering Zhengzhou University of Light IndustryZhengzhou 450000China National R&D Center for Edible Fungus Processing Technology Henan UniversityKaifeng 475004China

An acidic extracellular polysaccharide(EPS)was gained from Stropharia rugosoannulata fermentation broth by the alcohol precipitate *** derivative of EPS(S-EPS)was gained by chlorosulfonic acid-pyridine method and the conditions were as follows:pyridine as the reaction solvent,temperature 80°C,and reaction time 90 *** chemical structure and chain conformation of EPS and S-EPS were characterized by FT-Ir,NMr and size exclusion chromatography(SEC)coupled with multi-angle laser light scattering(MALLS)***-Ir spectra indicated the sulfated group was linked to the *** EPS mainly consists of mannose,glucose and glucuronic acid,and the glycosidic bond type is mainly(1→4)-linked and(1→6)-linked.C6 and C2 were substituted by sulfate *** EPS was degraded into smaller molecular weight(Mw)polysaccharides with the larger molecular size(rg)after sulfation and S-EPS has better ***,the sulfated derivative S-EPS was found to have a better scavenging ability on hydroxyl radicals than *** proved that the chemical modification of *** polysaccharides by sulfation effectively enhanced their antioxidant activity.

关键词： Polysaccharides Stropharia rugosoannulata Sulfation Antioxidant activity

来源：评论

学校读者我要写书评

暂无评论

Measurement and Frequency Characteristics Analysis of 500 kV Transformer Surface Vibration Signals 8

Measurement and Frequency Characteristics Analysis of 500 kV...

引用

8th Asia conference on Power and Electrical engineering, ACPEE 2023

作者： Li, Jingsong Sui, Xuewei Xu, Xinyu Li, Guofeng Zheng, Nianfeng Wang, Zhongqing Dalian University of Technology School of Electrical Engineering Dalian China R&D LUTE Electric Co. Ltd. Jining China

ISBN: (纸本)9798350345520

In this paper, the surface vibration signals of 500 kV autotransformer with different structures are measured, and the frequency domain characteristics of which are analyzed. Firstly, the surface vibration signal measuring points are set according to the specific arrangement of the core and windings of the transformer. Secondly, the vibration signals at different transformer measuring points under the same load and different loads are measured respectively. Finally, the frequency characteristics of the measured vibration signals are compared and analyzed. Then, use adaptive blind source separation algorithm (ABSSA) for transformer surface vibration signal processing, the two signals obtained are close to the vibration characteristics of core and windings respectively, and the same is true of the separated signals. It is proved that the accurate vibration signals of core and windings can be obtained by blind source separation, and is helpful for further analysis of the operation state of the transformer core and windings. © 2023 IEEE.

关键词： Frequency domain analysis

来源：评论

学校读者我要写书评

暂无评论

Optimizing environmental insulation thickness of buildings with CHP-based district heating system based on amount of energy and energy grade

引用

Frontiers in Energy 2022年第4期16卷 613-628页

作者： Yumei ZHANG Pengfei JIE Chunhua LIU Jing LI School of Mechanical Engineering Beijing Institute of Petrochemical TechnologyBeijing 102617China Engineering and Technology R&D Center of Clean Air Conditioning in Colleges of Shandong Shandong Huayu University of TechnologyDezhou 253000China China Environmental Resources Technology Co. LtdBeijing 100012China

The increase of insulation thickness(IT)results in the decrease of the heat demand and heat medium temperature.A mathematical model on the optimum environmental insulation thickness(OEIT)for minimizing the annual total environmental impact was established based on the amount of energy and energy grade ***,a case study was conducted based on a residential community with a combined heat and power(CHP)-based district heating system(dHS)in Tianjin,***,the effect of IT on heat demand,heat medium temperature,exhaust heat,extracted heat,coal consumption,carbon dioxide(co_(2))emissions and sulfur dioxide(SO_(2))emissions as well as the effect of three types of insulation materials(i.e.,expanded polystyrene,rock wool and glass wool)on the OEIT and minimum annual total environmental impact were *** results reveal that the optimization model can be used to determine the *** the OEIT of expanded polystyrene,rock wool and glass wool is used,the annual total environmental impact can be reduced by 84.563%,83.211%,and 86.104%,*** can be found that glass wool is more beneficial to the environment compared with expanded polystyrene and rock wool.

关键词： optimum environmental insulation thickness heat medium temperature energy grade extracted heat exhaust heat

来源：评论

学校读者我要写书评

暂无评论

Optimization of High Voltage and Large Capacity Circuit Breakers Based on Parallel Flow Field Calculation 13

Optimization of High Voltage and Large Capacity Circuit Brea...

引用

13th International conference on Power and Energy Systems, ICPES 2023

作者： Zhang, Hao Wang, Zhijun Song, Yunlei Li, Miaoxin Liu, Yapei Yao, Yongqi Pinggao Group Co. Ltd R&d Centre Pingdingshan China Shenyang University of Technology School of Electric Engineering Shenyang China

ISBN: (纸本)9798350345063

In the process of high-voltage circuit breaker breaking, the arc extinguishing chamber is a complex multi-field coupling physical process, and the simulation technology of the flow field in the arc extinguishing chamber is the core technology of circuit breaker design. The early simulation technology of airflow field in arc extinguishing chamber uses single core calculation, which takes a long time and cannot meet the requirements of product development cycle. Based on the arc mathematical model, this paper developed the parallel simulation technology of the gas field in the arc extinguishing chamber, analyzed the calculation results of the pressure and temperature of the arc extinguishing chamber under the typical short-circuit breaking condition. The influence of different nozzle throat diameters on the airflow field of high-voltage and large-capacity interrupter was studied, and the optimization direction of the interrupter structure was determined to complete the product optimization design. © 2023 IEEE.

关键词： Flow fields

来源：评论

学校读者我要写书评

暂无评论

Novel polyimide binder for achieving high-rate capability and long-term cycling stability of LiNi_(0.8)co_(0.1)Mn_(0.1)O_(2) cathode via constructing polar and micro-branched crosslinking network structure

引用

Journal of Energy Chemistry 2023年第1期76卷 19-31,I0002页

作者： Yueming Xu Yali Wang Nanxi dong Chuanzhi Pu Bingxue Liu Guofeng Tian Shengli Qi dezhen Wu State Key Laboratory of Chemical Resource Engineering Beijing University of Chemical TechnologyBeijing 100029China ENFI R&D Institute China ENFI EngineeringCorporationBeijing 100038China China Automotive Battery Research Institute Co. Ltd.Beijing 101407China

LiNi_(0.8)co_(0.1)Mn_(0.1)O_(2)(NCM811)material,as the promising cathode candidate for next-generation highenergy lithium-ion batteries,has gained considerable attention for extremely high theoretical capacity and low ***,the intrinsic drawbacks of NCM811 such as unstable structure and inevitable interface side reaction result in severe capacity decay and thermal ***,a novel polyimide(denoted as PI-Om dT)constructed with the highly polar and micro-branched crosslinking network is reported as a binder material for NCM811 *** micro-branched crosslinking network is achieved by using 1,3,5-Tris(4-aminophenoxy)benzene(TAPOB)as a crosslinker via condensation reaction,which endows excellent mechanical properties and large free ***,the massive polar carboxyl(-coOH)groups provide strong adhesion sites to active NCM811 *** functions of PIOm dT binder collaboratively benefit to forming the mechanically robust and homogeneous coating layer with rapid Li+diffusion on the surface of NCM811,significantly stabilizing the cathode structure,suppressing the detrimental interface side reaction and guaranteeing the shorter ion-diffusion and electron-transfer paths,consequently enhancing electrochemical *** compared to the NCM811 with PVdF binder,the NCM811 using PI-Om dT binder delivers a superior high-rate capacity(121.07 vs.145.38 m Ah g^(-1))at 5 C rate and maintains a higher capacity retention(80.38%vs.91.6%)after100 cycles at 2.5–4.3 ***,at the high-voltage conditions up to 4.5 and 4.7 V,the NCM811 with PI-Om dT binder still maintains the remarkable capacity retention of 88.86%and 72.5%after 100 cycles,respectively,paving the way for addressing the high-voltage operating stability of the NCM811 ***,the full-charged NCM811 cathode with PI-Om dT binder exhibits a significantly enhanced thermal stability,improving the safety performance of *** work opens a new avenue for developing

关键词： Polyimide Binder Micro-branched crosslinking network NCM811 cathode Lithium-ion battery

来源：评论

学校读者我要写书评

暂无评论

design of Hydrodynamic Journal Bearing for Integrally Geared Centrifugal compressor 6

Design of Hydrodynamic Journal Bearing for Integrally Geared...

引用

6th International conference on contemporary computing and Informatics, IC3I 2023

作者： More, Kaushik Korwar, Ganesh Satpute, Nitin Masal, Kushal Patel, Viralkumar Vishwakarma Institute of Technology Department of Mechanical Engineering Pune India R&D Kirloskar Pneumatics Co. Ltd. Pune India

ISBN: (纸本)9798350304480

With performance considerations driving the design of rotating equipment, operating speeds and journal loads have increased greatly in recent years, often exceeding generally accepted design limits. For high performance applications including integrally geared compressors, tilting pad bearings are often used as they are subjected to both high speeds and loads. This paper presents design of tilting pad bearing for an integrally geared centrifugal compressor where the shaft stiffness and the bearing stiffness are in the moderate range. A rotor model was created to study the response of the system. Critical speed mode shapes, undamped critical speed map and Bode plot are plotted for this rotor model. The analysis is carried out at maximum continuous operating speed of 31000 rpm (± 5%) which lies between the 2nd and 3rd critical speeds. This paper illustrates design of tilting pad bearing along with rotordynamic analysis which helps to explain the rotor response and provide assurance that Separation Margin are within acceptable limits mentioned in API-672. Speed at the vibration probe location of the rotor from the dyroBeS software and on-site data of the same are compared in which we observed a percentage variation of 3.29% in first stage vibration probe location and 10.9% in second stage vibration probe location which are within acceptable limits. © 2023 IEEE.

关键词： Bode plot compressor critical speed stiffness tilting pad bearing vibration

来源：评论

学校读者我要写书评

暂无评论

A deoxidation thermodynamic model for 304 stainless steel considering multiple-components coupled reactions

引用

Journal of Iron and Steel research International 2024年第1期31卷 74-91页

作者： Yan Yan Guang-hao Shang Li-ping Zhang Shao-ying Li Han-jie Guo School of Metallurgical and Ecological Engineering University of Science and Technology BeijingBeijing100083China Beijing Key Laboratory of Special Melting and Preparation of High-End Metal Materials Beijing100083China Henan Jinhui Stainless Steel Industry Group Co. Ltd.Xuchang461500HenanChina Changge Jinhui Recycling Metal R&D Co. Ltd.Xuchang461500HenanChina

A thermodynamic model for predicting the equilibrium oxygens of 304 stainless steel was developed based on the theory of slag-steel equilibrium,the law of mass conservation,and the ion and molecule coexistence *** the developed model,the Fe-Cr-Mn-Si-Al-S-O-melts reaction system and CaO-MgO-CaF_(2)-FeO-MnO-Al_(2)O_(3)-SiO_(2)-Cr2O_(3)slags were *** oxygen contents calculated by the model are in good agreement with experimental results and reference *** equilibrium oxygen contents in 304 stainless steel mainly decrease with increasing binary basicity(w(CaO)/w(SiO_(2)),where w(i)is the mass percentage of component i)and decreasing *** binary basicity at 2.0 while maintaining temperatures lower than 1823 K will keep the oxygen contents in the 304 stainless steel lower than 15×10^(-6).The equilibrium oxygen contents may also be decreased with increasing content of MgO in slags,which is more significant at lower binary ***,a small amount of FeO,MnO,and Al_(2)O_(3)(about 0-2.5 wt.%)in slags has little effect on equilibrium oxygen ***,it is found that the[C]-[O]reaction may occur during refining process but will not significantly affect the equilibrium oxygen contents.

关键词： complex deoxidation Thermodynamic model Ion and molecule coexistence theory 304 stainless steel Slag-steel reaction

来源：评论

学校读者我要写书评

暂无评论

Efficient drilling technology of Horizontal Wells in the duverney Block in Canada

Efficient Drilling Technology of Horizontal Wells in the Duv...

引用

2021 Abu dhabi International Petroleum Exhibition and conference, AdIP 2021

作者： Han, Haochen Yang, Guobin Zhang, Guobin Chen, Jia Chen, Peter Fu, Jin Wang, Siqi CNPC Engineering and Technology R&D Company CNPC Materials Procurement Center CNPC GreatWall Drilling Company Ltd.

ISBN: (纸本)9781613998342

recent years, both exploration and development have made considerable progress in the duverney block shale gas in Canada. However, technical problems exposed in horizontal drilling engineering need to be optimized: 1) Loss is common in shallow formations;2) High downhole friction torque, low rOP and drilling cuttings accumulation in long horizontal well section;3) Borehole instability leads to hanger or packer failure;4) drill bits and PdM have short servicing life and low efficiency. Optimization comes from three aspects: (1) Based on previous drilling experience and latest formation condition and development requirement, we design a new well profile for the block taking into drilling safety and further development account;(2) Optimize strong inhibitive, easy-maintenance and high cutting-carrying capacity OBM to ensure the safety requirements in the ultra-long open hole section;(3) BHA and parameters optimization. Optimize drill bit with high-abrasiveness and axial efficiency according to logging data, drillability and UCS. Upgrade conventional PdM into high-performance PdM with even-wall thickness. By means of simulation and calculation, drilling parameters suitable for duverney block has been optimized. Based on the optimization above, a stable and efficient well profile has been improved solving hanger failure on-site efficiently and complete with composite casing design (4-1/2 inch plus 5 inch) in reservoir section;a 90/10 oil-water ratio OBM has been optimized and applied onsite;combined with high performance PdC bit and even-wall PdM as well as optimized drilling parameters, higher rOP and longer horizontal section have been achieved. The optimization has made successful field application results:(1) completion depth has been deepened gradually, from 18,080 ft in 2013 to 23,208 ft at present, with an increase of 28.3%;(2) Horizontal section length has been increasing dramatically, from 6,190 ft in 2013 to 10,301 ft at present, with an increase of 66.4%;(3) Th

关键词： Horizontal wells

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：