检索结果-南通市图书馆

Effects of the initiation position on the damage and fracture characteristics of linear-charge blasting in rock

International Journal of Minerals,Metallurgy and Materials 2024年第3期31卷 443-451页

作者： Chenxi Ding Renshu Yang xiao guo Zhe Sui Chenglong xiao Liyun Yang School of Civil and Resource Engineering University of Science and Technology BeijingBeijing 100083China School of Mechanics and Civil Engineering China University of Mining and Technology(Beijing)Beijing 100083China School of Mathematics and Physics University of Science and Technology BeijingBeijing 100083China State Key Lab of Explosion Science and Technology Beijing Institute of TechnologyBeijing 100081China

To study the effects of the initiation position on the damage and fracture characteristics of linear-charge blasting, blasting model experiments were conducted in this study using computed tomography scanning and three-dimensional reconstruction methods. The fractal damage theory was used to quantify the crack distribution and damage degree of sandstone specimens after blasting. The results showed that regardless of an inverse or top initiation, due to compression deformation and sliding frictional resistance, the plugging medium of the borehole is effective. The energy of the explosive gas near the top of the borehole is consumed. This affects the effective crushing of rocks near the top of the borehole, where the extent of damage to Sections Ⅰ and Ⅱ is less than that of Sections Ⅲ and Ⅳ. In addition, the analysis revealed that under conditions of top initiation, the reflected tensile damage of the rock at the free face of the top of the borehole and the compression deformation of the plug and friction consume more blasting energy, resulting in lower blasting energy efficiency for top initiation. As a result, the overall damage degree of the specimens in the top-initiation group was significantly smaller than that in the inverse-initiation group. Under conditions of inverse initiation, the blasting energy efficiency is greater, causing the specimen to experience greater damage. Therefore, in the engineering practice of rock tunnel cut blasting, to utilize blasting energy effectively and enhance the effects of rock fragmentation, using the inverse-initiation method is recommended. In addition, in three-dimensional(3D) rock blasting, the bottom of the borehole has obvious end effects under the conditions of inverse initiation, and the crack distribution at the bottom of the borehole is trumpet-shaped. The occurrence of an end effect in the 3D linear-charge blasting model experiment is related to the initiation position and the blocking condition.

关键词： blasting linear charge initiation position computed tomography three-dimensional reconstruction damage

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Design and Implementation of Nonlinear Precoding for MIMO-SDMA Toward 6G Wireless

引用

China Communications 2024年第1期21卷 69-87页

作者： Chaowu Wu Yue xiao Shu fang Gang Wu National Key Laboratory of Wireless Communications University of Electronic Science and Technology of ChinaChengdu 611731China

In this paper,we present a novel and robust nonlinear precoding(NLP)design and detection structure specifically tailored for multiple-input multipleoutput space division multiple access(MIMO-SDMA)systems toward 6G *** approach aims to effectively mitigate the impact of imperfect channel estimation by leveraging the channel fluctuation mean square error(MSE)for reconstructing a highly accurate precoding matrix at the ***,we introduce a simplified receiver structure that eliminates the need for equalization,resulting in reduced interference and notable enhancements in overall system *** conduct both computer simulations and experimental tests to validate the efficacy of our proposed *** results reveals that the proposed NLP scheme offers significant performance improvements,making it particularly well-suited for the forthcoming 6G wireless.

关键词： MIMO-SDMA nonlinear precoding Tomlinson-Harashima precoding(THP) vector perturbation(VP)

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Bald Eagle Search Optimization Algorithm Combined with Spherical Random Shrinkage Mechanism and Its Application

引用

Journal of Bionic Engineering 2024年第1期21卷 572-605页

作者： Wenyan guo Zhuolin Hou fang Dai xiaoxia Wang Yufan Qiang Department of Applied Mathematics School of ScienceXi'an University of TechnologyXian 710054ShaanxiChina

Over the last two decades,stochastic optimization algorithms have proved to be a very promising approach to solving a variety of complex optimization *** eagle search optimization(BES)as a new stochastic optimization algorithm with fast convergence speed has the ability of prominent optimization and the defect of collapsing in the local *** avoid BES collapse at local optima,inspired by the fact that the volume of the sphere is the largest when the surface area is certain,an improved bald eagle search optimization algorithm(INMBES)integrating the random shrinkage mechanism of the sphere is ***,the INMBES embeds spherical coordinates to design a more accurate parameter update method to modify the coverage and dispersion of the ***,the population splits into elite and non-elite groups and the Bernoulli chaos is applied to elite group to tap around potential solutions of the *** non-elite group is redistributed again and the Nelder-Mead simplex strategy is applied to each group to accelerate the evolution of the worst individual and the convergence process of the *** results of Friedman and Wilcoxon rank sum tests of CEC2017 in 10,30,50,and 100 dimensions numerical optimization confirm that the INMBES has superior performance in convergence accuracy and avoiding falling into local optimization compared with other potential improved algorithms but inferior to the champion algorithm and ranking *** three engineering constraint optimization problems and 26 real world problems and the problem of extracting the best feature subset by encapsulated feature selection method verify that the INMBES’s performance ranks first and has achieved satisfactory accuracy in solving practical problems.

关键词： Bald eagle search optimization algorithm Spherical coordinates Chaotic variation Simplex method Encapsulated feature selection

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Structural and magnetic properties of micropolycrystalline cobalt thin films fabricated by direct current magnetron sputtering

引用

International Journal of Minerals,Metallurgy and Materials 2024年第2期31卷 384-394页

作者： Kerui Song Zhou Li Mei fang Zhu xiao Qian Lei School of Materials Science and Engineering Central South UniversityChangsha 410083China State Key Laboratory of Powder Metallurgy Central South UniversityChangsha 410083China Hunan Key Laboratory of Super-Microstructure and Ultrafast Process School of Physics and electronicsCentral South UniversityChangsha 410083China Key Laboratory of Non-Ferrous Metal Materials Science and Engineering Ministry of EducationChangsha 410083China

Pure cobalt(Co)thin films were fabricated by direct current magnetron sputtering,and the effects of sputtering power and pres-sure on the microstructure and electromagnetic properties of the films were *** the sputtering power increases from 15 to 60 W,the Co thin films transition from an amorphous to a polycrystalline state,accompanied by an increase in the intercrystal pore ***,the resistivity decreases from 276 to 99μΩ·cm,coercivity increases from 162 to 293 Oe,and in-plane magnetic aniso-tropy *** the sputtering pressure decreases from 1.6 to 0.2 Pa,grain size significantly increases,resistivity significantly de-creases,and the coercivity significantly increases(from 67 to 280 Oe),which can be attributed to the increase in defect ***-pondingly,a quantitative model for the coercivity of Co thin films was *** polycrystalline films sputtered under pressures of 0.2 and 0.4 Pa exhibit significant in-plane magnetic anisotropy,which is primarily attributable to increased microstress.

关键词： cobalt thin film magnetron sputtering microstructure electromagnetic properties

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Physical neural networks with self-learning capabilities

引用

Science China(Physics,Mechanics & Astronomy) 2024年第8期67卷 23-42页

作者： Weichao Yu Hangwen guo Jiang xiao Jian Shen State Key Laboratory of Surface Physics and Institute for Nanoelectronic Devices and Quantum Computing Fudan UniversityShanghai 200433China Zhangjiang Fudan International Innovation Center Fudan UniversityShanghai 201210China Department of Physics Fudan UniversityShanghai 200433China Shanghai Research Center for Quantum Sciences Shanghai 201315China Collaborative Innovation Center of Advanced Microstructures Nanjing 210093China

Physical neural networks are artificial neural networks that mimic synapses and neurons using physical systems or *** networks harness the distinctive characteristics of physical systems to carry out computations effectively,potentially surpassing the constraints of conventional digital neural networks.A recent advancement known as“physical self-learning”aims to achieve learning through intrinsic physical processes rather than relying on external *** article offers a comprehensive review of the progress made in implementing physical self-learning across various physical *** learning strategies that contribute to the realization of physical self-learning are *** challenges in understanding the fundamental mechanism of learning,this work highlights the progress towards constructing intelligent hardware from the ground up,incorporating embedded self-organizing and self-adaptive dynamics in physical systems.

关键词： self-learning physical neural networks neuromorphic computing physical learning

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Adeno-associated virus vectors simultaneously encoding VEGF and angiopoietin-1 enhances neovascularization in ischemic rabbit hindlimbs

引用

Acta Pharmacologica Sinica 2007年第4期28卷 493-502页

作者： Feng CHEN Zui TAN Department of Vascular Surgery,Zhongnan Hospital,Wuhan UniversityChang-yuan DONG xiao CHEN Shu-fang guo State Key Laboratory of Virology,Medical College,Wuhan University,Wuhan 430071,China Department of Vascular Surgery Zhongnan Hospital Wuhan University Wuhan China State Key Laboratory of Virology Medical College Wuhan University Wuhan China

Aim:Angiopoietin-1 (Ang1) and vascular endothelial growth factor A (VEGF)play important roles in vascular formation and maturation,suggesting a combina-tion of these 2 would be a promising therapy for ischemic *** we con-structed an adeno-associated virus (AAV) vector,simultaneously encoding hu-man VEGF165and Ang 1 (AAV-VEGF/Ang 1),and investigated its therapeutic effectin a rabbit ischemic hind-limb ***:Four experimental groups wereused to prepare the rabbit ischemic hind-limb model following AAV vectors intra-muscular administration as follows:PBS (phosphate buffered solution),AAV-VEGF,AAV-Ang1,AAV-VEGF/***:Eight weeks after administration,humanVEGF165and Ang1 were detected by RT-PCR,Western blotting and histochemicalstaining methods in AAV-VEGF/Ang1 transduced *** AAV-VEGF/Ang1 showed a significantly increased blood-flow recovery in ischemic hind-limbs compared with the other *** staining for alkaline phos-phatase showed that capillary density of group AAV-VEGF/Ang1 or AAV-VEGFwas significantly higher than that of group PBS or *** for smooth muscle α-actin (α-SMA) revealed that group AAV-VEGF/Ang 1 had the highest density of α-SMA-positive vessels compared withthe other *** leakage,one of the major adverse effects induced byVEGF,was very severe in group AAV-VEGF,but the permeability was obviouslyreduced when VEGF was co-expressed with Ang1 in group AAV-VEGF/***:AAV vectors can simultaneously encode 2 proteins which can beefficiently and stably co-expressed in transduced ***-mediated VEGFand Ang1 gene transfer enhances neovascularization,prevents capillary leakage,and improves blood flow in a rabbit hind-limb ischemic *** findingssuggest that intramuscular administration of AAV-VEGF/Ang 1 may be useful inthe treatment of ischemic diseases.

关键词： adeno-associated virus vascular endothelial growth factor A angiopoietin-l neovascularization ischemia

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Distribution of oxide inclusions in H13 castings under super-gravity field with multi-stage rotation speeds

引用

Journal of Iron and Steel Research International 2024年第1期31卷 121-133页

作者： Shao-ying Li xiao-jun Xi Xing-ming Zhao Han-jie guo Jing guo School of Metallurgical and Ecological Engineering University of Science and Technology Beijing(USTB)Beijing100083China Beijing Key Laboratory of Special Melting and Preparation of High-End Metal Materials Beijing100083China Beijing Beiye Functional Materials Corporation Beijing100192China Shandong Tianwu Forming Technology Co. Ltd.Liaocheng252024ShandongChina

The 42 kg industrial H13 castings were prepared by different super-gravity fields with multi-rotation speeds,and the distribution of oxide inclusions in the castings was *** addition,the inward movement Reynolds number and inward movement time of oxide inclusions as well as the solidification time of molten steel at different positions in the castings were calculated to clarify the removal mechanism of oxide inclusions in super-gravity *** results show that the large size(i.e.,greater than 10μm)oxide inclusions are mainly concentrated in the inner and outer parts of the super-gravity castings with constant rotation speed(500 r min^(-1))and five-stage rotation speeds(500,600,750,850,and 950 r min^(-1)),respectively,while there are no large oxide inclusions in the super-gravity castings with three-stage rotation speeds(500,600,and 750 r min^(-1)).Although an increase in the particle size of inclusion and the rotation speed in super-gravity field is conducive to the increase in the inward movement Reynolds number of oxide inclusions and reduction in the inward movement time of oxide inclusions,it will reduce the local solidification time of molten *** the range of the rotation speed studied,the super-gravity field with three-stage rotation speeds has the best effect on the removal of inclusions in H13 molten steel.

关键词： Distribution Oxide inclusion H13 casting Super-gravity field Rotation speed

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Nomogram based on liver stiffness and spleen area with ultrasound for posthepatectomy liver failure:A multicenter study

引用

World Journal of Gastroenterology 2024年第27期30卷 3314-3325页

作者： Guang-Wen Cheng Yan fang Li-Yun Xue xiao-Hui Qiao Xue-Qi Li Yan Zhang Jia guo xiao-Yan Xie Hong Ding Department of Ultrasound Huashan HospitalFudan UniversityShanghai 200040China Department of Ultrasound Shuguang Hospital Affiliated to Shanghai University of Traditional Chinese MedicineShanghai 201203China Department of Medical Ultrasonics Institute of Diagnostic and Interventional UltrasoundSun Yat-sen University First Affiliated HospitalGuangzhou 510080Guangdong ProvinceChina Institute of Ultrasound in Medicine and Engineering Shanghai Cancer CenterShanghai 200040China Department of Ultrasound Eastern Hepatobiliary Surgical HospitalSecond Military Medical UniversityShanghai 200433China Department of Ultrasound National Clinical Research Center for Aging and MedicineHuashan HospitalFudan UniversityShanghai 200040China

BACKGROUND Liver stiffness(LS)measurement with two-dimensional shear wave elastography(2D-SWE)correlates with the degree of liver fibrosis and thus indirectly reflects liver function *** size of the spleen increases due to tissue proliferation,fibrosis,and portal vein congestion,which can indirectly reflect the situation of liver fibrosis/*** was reported that the size of the spleen was related to posthepatectomy liver failure(PHLF).So far,there has been no study combining 2D-SWE measurements of LS with spleen size to predict *** prospective study aimed to investigate the utility of 2D-SWE assessing LS and spleen area(SPA)for the prediction of PHLF in hepatocellular carcinoma(HCC)patients and to develop a risk prediction *** To investigate the utility of 2D-SWE assessing LS and SPA for the prediction of PHLF in HCC patients and to develop a risk prediction *** This was a multicenter observational study prospectively analyzing patients who underwent hepatectomy from October 2020 to March *** 1 wk before partial hepatectomy,ultrasound examination was performed to measure LS and SPA,and blood was drawn to evaluate the patient’s liver function and other *** absolute shrinkage and selection operator logistic regression and multivariate logistic regression analysis was applied to identify independent predictors of PHLF and develop a *** performance was validated *** diagnostic performance of the nomogram was evaluated with receiver operating charac-teristic curve compared with the conventional models,including the model for end-stage liver disease(MELD)score and the albumin-bilirubin(ALBI)*** A total of 562 HCC patients undergoing hepatectomy(500 in the training cohort and 62 in the validation cohort)were enrolled in this *** independent predictors of PHLF were LS,SPA,range of resection,blood loss,international normalized ratio,and total *** diagnostic performanc

关键词： Shear-wave elastography Spleen Hepatectomy Posthepatectomy liver failure Hepatocellular carcinoma

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Improved Flexible Triboelectric Nanogenerator Based on Tile-Nanostructure for Wireless Human Health Monitor

引用

Energy & Environmental Materials 2024年第4期7卷 386-395页

作者： Huamin Chen Shujun guo Shaochun Zhang Yu xiao Wei Yang Zhaoyang Sun Xu Cai Run fang Huining Wang Yun Xu Jun Wang Zhou Li Fujian Key Laboratory of Functional Marine Sensing Materials Minjiang University Beijing Institute of Nanoenergy and Nanosystems Chinese Academy of Sciences Institute of Semiconductors Chinese Academy of Sciences Beijing Key Laboratory of Inorganic Stretchable and Flexible Information Technology Faculty of Science and Engineering The University of Nottingham Ningbo China

Triboelectric nanogenerators (TENCs) have emerged as promising candidates for integrating with flexible electronics as self-powered systems owing to their intrinsic flexibility,biocompatibility,and *** this study,an improved flexible TENC with a tile-nanostructured MXene/polymethyl methacrylate (PMMA) composite electrode (MP-TENC) is proposed for use in wireless human health monitor.

关键词： flexible electrode MXene tile nanostructure triboelectric nanogenerator wireless monitor

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Genetically modified pigs:Emerging animal models for hereditary hearing loss

引用

Zoological Research 2024年第2期45卷 284-291页

作者： xiao Wang Tian-Xia Liu Ying Zhang Liang-Wei Xu Shuo-Long Yuan A-Long Cui Wei-Wei guo Yan-fang Wang Shi-Ming Yang Jian-guo Zhao State Key Laboratory of Stem Cell and Reproductive Biology Institute of ZoologyChinese Academy of SciencesBeijing 100101China Savaid Medical School University of Chinese Academy of SciencesBeijing 100049China Institute for Stem Cell and Regeneration Chinese Academy of SciencesBeijing 100101China Beijing Institute for Stem Cell and Regenerative Medicine Beijing 100101China Department of Otolaryngology-Head and Neck Surgery Institute of OtolaryngologyChinese PLA General HospitalBeijing 100853China Division of Life Sciences and Medicine University of Science and Technology of ChinaHefeiAnhui 230022China State Key Laboratory of Animal Biotech Breeding Institute of Animal ScienceChinese Academy of Agricultural SciencesBeijing100193China

Hereditary hearing loss(HHL),a genetic disorder that impairs auditory function,significantly affects quality of life and incurs substantial economic losses for *** investigate the underlying causes of HHL and evaluate therapeutic outcomes,appropriate animal models are *** have been extensively used as valuable large animal models in biomedical *** this review,we highlight the advantages of pig models in terms of ear anatomy,inner ear morphology,and electrophysiological characteristics,as well as recent advancements in the development of distinct genetically modified porcine models of hearing ***,we discuss the prospects,challenges,and recommendations regarding the use pig models in HHL ***,this review provides insights and perspectives for future studies on HHL using porcine models.

关键词： Pigs Animal models Hereditary hearing loss Genetic modification Inner ear

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

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

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

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

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

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：