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碱液(NaOH)对风积砂强度的影响与微观作用机理研究

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土工基础 2024年第3期38卷 479-484页

作者：张重重张宁陈筠陈泰徐常强贵州大学资源与环境工程学院贵阳550025 中国电建集团贵阳勘测设计研究院贵阳550081 贵州理工学院继续教育学院贵阳550003

针对工程中风积砂强度不足的问题,利用碱液(NaOH)对风积砂进行处理。为验证风积砂强度是否改变,采用直剪试验进行判断,并找到较为合适的碱液浓度。为研究碱液对风积砂强化的微观作用机理,采用电镜扫描观测风积砂微观结构,并利用IPP(Imag... 详细信息

针对工程中风积砂强度不足的问题,利用碱液(NaOH)对风积砂进行处理。为验证风积砂强度是否改变,采用直剪试验进行判断,并找到较为合适的碱液浓度。为研究碱液对风积砂强化的微观作用机理,采用电镜扫描观测风积砂微观结构,并利用IPP(Image-Pro Plus)图像分析软件与PCAS软件对风积砂微观图像进行处理,提取微观参数。结果表明:(1)碱液的加入可以显著的提高风积砂的强度,但额外补充的Ca2+不会使土体强度得到更为有效的提升;(2)碱液浓度的提高会使土体的抗剪强度提升,但存在最优含量区间,过高的碱液浓度不会使抗剪强度得到更为明显的提升;(3)碱液加固后风积砂强度的变化与孔隙微观结构的变化之间存在一定关系;(4)微观作用机理上,NaOH与土体发生作用,产生片状聚合物去填充土体孔隙,并附着在颗粒表面,包裹土体颗粒,使土体强度得到提高。

关键词：风积砂 NaOH 直剪试验微观结构 SEM

A toroidal SAW gyroscope with focused IDTs for sensitivity enhancement

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Microsystems & Nanoengineering 2024年第2期10卷 47-56页

作者： Lu Tian Haitao Zhao qiang Shen Honglong chang Ministry of Education Key Laboratory of Micro and Nano Systems for Aerospace School of Mechanical EngineeringNorthwestern Polytechnical UniversityXi’an710072China

A surface acoustic wave(SAW)gyroscope measures the rate of rotational angular velocity by exploiting a phenomenon known as the SAW gyroscope *** a gyroscope is a great candidate for application in harsh environments because of the simplification of the suspension vibration mechanism necessary for traditional microelectromechanical system(MEMS)***,for the first time,we propose a novel toroidal standing-wave-mode SAW gyroscope using focused interdigitated transducers(FIDTs).Unlike traditional SAW gyroscopes that use linear IDTs to generate surface acoustic waves,which cause beam deflection and result in energy dissipation,this study uses FIDTs to concentrate the SAW energy based on structural features,resulting in better focusing performance and increased SAW *** experimental results reveal that the sensitivity of the structure is 1.51µV/(°/s),and the bias instability is 0.77°/s,which are improved by an order of magnitude compared to those of a traditional SAW ***,the FIDT component can enhance the performance of the SAW gyroscope,demonstrating its superiority for angular velocity *** work provides new insights into improving the sensitivity and performance of SAW gyroscopes.

关键词： angular deflection gyroscope

糖尿病足导致跟骨骨髓炎继发跟骨病理性鸟嘴样骨折的治疗效果

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中国骨伤 2024年第6期37卷 609-615页

作者：李炜峰高彦军王士波阮培灿邱元洲何昌强深圳市罗湖区中医院创伤骨科与足踝外科广东深圳518001

目的 :探讨万古霉素硫酸钙联合内固定治疗糖尿病足导致跟骨骨髓炎继发跟骨病理性“鸟嘴样”骨折的临床疗效。方法:回顾性分析2018年4月至2021年10月收治的5例糖尿病足导致跟骨骨髓炎继发跟骨病理性“鸟嘴样”骨折患者,男2例,女3例;年龄4... 详细信息

目的 :探讨万古霉素硫酸钙联合内固定治疗糖尿病足导致跟骨骨髓炎继发跟骨病理性“鸟嘴样”骨折的临床疗效。方法:回顾性分析2018年4月至2021年10月收治的5例糖尿病足导致跟骨骨髓炎继发跟骨病理性“鸟嘴样”骨折患者,男2例,女3例;年龄48~60岁;糖尿病病程5~13年;糖尿病足病程18~52 d;按Wagner分级均为Ⅲ级。所有患者根据病情Ⅰ期实施清创术,万古霉素骨水泥植入,负压吸引术;Ⅱ期使用万古霉素硫酸钙加内固定治疗跟骨病理性“鸟嘴样”骨折。记录患者手术切口、骨折愈合时间,观察骨髓炎复发情况,评价术后12个月美国足与踝关节协会踝与后足评分(American Orthopedic Foot Andankle Society,AOFAS)及渗出等并发症情况。结果:5例顺利完成手术,所有患者未出现下肢血管闭塞。5例获得随访,时间16~36个月。骨折内固定术后切口愈合时间16~26 d,所有骨折愈合,愈合时间16~27周。术后12个月AOFAS评分65~91分;其中优2例,良2例,可1例。其中1例术后5个月因烫伤导致足背部皮肤溃疡(非并发症),经治疗后痊愈;2例出现伤口渗漏并发症,经换药后伤口痊愈;所有患者未再发骨髓炎及骨折。结论:万古霉素硫酸钙联合内固定治疗糖尿病足导致跟骨骨髓炎继发跟骨病理性“鸟嘴样”骨折在控制感染的同时可促进骨折愈合,可获得较好的临床效果。

关键词：糖尿病足病理性骨折骨髓炎万古霉素骨水泥万古霉素硫酸钙

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正交试验法优选大黄丁产地趁鲜加工工艺

湖北农业科学 2024年第1期63卷 138-141页

作者：黄浩胡昌强段媛媛郭晓亮湖北省农业科学院中药材研究所/农业农村部中药材生物学与栽培重点实验室湖北恩施445000 持正堂药业恩施有限公司湖北恩施445000

为了优选大黄丁产地趁鲜加工工艺,采用正交试验法考察圆片厚度、初干温度、干燥程度、复干温度4个因素对大黄丁水分、游离蒽醌、总蒽醌、干燥时长的影响。结果表明,4个因素对大黄丁总蒽醌含量的影响均不显著;圆片厚度、初干温度对大黄... 详细信息

为了优选大黄丁产地趁鲜加工工艺,采用正交试验法考察圆片厚度、初干温度、干燥程度、复干温度4个因素对大黄丁水分、游离蒽醌、总蒽醌、干燥时长的影响。结果表明,4个因素对大黄丁总蒽醌含量的影响均不显著;圆片厚度、初干温度对大黄丁游离蒽醌含量影响显著;干燥程度对大黄丁水分影响极显著;各因素对大黄丁总干燥时长影响显著或极显著。大黄丁产地趁鲜加工最佳工艺为将处理好的鲜大黄根茎横切为厚12 mm的圆片,于60℃干燥至含水量60%,再将圆片按长宽各12 mm切丁,然后70℃干燥至含水量13%以下。以该加工工艺生产大黄丁,游离蒽醌含量较高,干燥用时较短,总蒽醌含量无显著下降。

关键词：大黄丁产地趁鲜加工工艺游离蒽醌总蒽醌总干燥时长正交试验

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黄柏产地趁鲜加工工艺及其可行性研究

湖北农业科学 2024年第1期63卷 102-105,111页

为了优化黄柏(Phellodendron chinense Schneid.)趁鲜加工工艺,并验证其可行性,采用正交试验设计,考察工艺参数对黄柏丝质量的影响,并对趁鲜加工黄柏丝进行质量评价。结果表明,初干温度对黄柏丝的质量存在显著影响;初干温度、初干程度... 详细信息

为了优化黄柏(Phellodendron chinense Schneid.)趁鲜加工工艺,并验证其可行性,采用正交试验设计,考察工艺参数对黄柏丝质量的影响,并对趁鲜加工黄柏丝进行质量评价。结果表明,初干温度对黄柏丝的质量存在显著影响;初干温度、初干程度、复干温度均对黄柏丝加工效率有极显著影响。综合考虑黄柏丝质量、干燥时长、能耗,最适加工工艺为切丝前自然晾晒或45℃干燥至含水量43%~50%时切丝,而后45℃干燥至含水量12%以下。趁鲜加工的黄柏丝性状、水分、总灰分、浸出物、小檗碱、黄柏碱含量均符合《中华人民共和国药典》要求,质量与市售黄柏丝无显著差异,优于传统加工黄柏丝。因此,川黄柏产地趁鲜加工取代传统方法是可行的。

关键词：黄柏(Phellodendron chinense Schneid.) 产地趁鲜加工质量加工效率可行性

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Recent Advances in Asymmetric Structural Composites for Excellent Electromagnetic Interference Shielding: A Review

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Chinese Journal of Polymer Science 2024年第6期42卷 693-710页

作者： Ying Zhou Bai Xue Lan Xie chang-Mei Wu qiang Zheng Department of Polymer Materials and Engineering College of Materials and Metallurgy Guizhou University National Engineering Research Center for Compounding and Modification of Polymer Materials National and Local Joint Engineering Research Center for Functional Polymer Membrane Materials and Membrane Processes State Key Laboratory of Public Big Data Guizhou University Department of Polymer Science and Engineering Zhejiang University

Since electromagnetic pollution is detrimental to human health and the environment, numerous efforts have been successively made to achieve excellent electromagnetic interference shielding effectiveness(EMI SE) via designing the hierarchical structures for electromagnetic interference(EMI) shielding polymer composites. Among the plentiful structures, the asymmetric structures are currently a hot spot, principally categorizing into multi-layered, porous, fibrous, and segregated asymmetric structures, which endows the high EMI shielding performance for polymer composites incorporated with magnetic, conductive, and/or dielectric micro/nano-fillers, due to the “absorption-reflection-reabsorption” shielding mechanism. Therefore, this review provides the retrospection and summary of the efforts with respect to abundant asymmetric structures and multifunctional micro/nano-fillers for enhancing EMI shielding properties, which is conducive to the booming development of polymeric EMI shielding materials for the promising prospect in modern electronics and 5-generation(5G) technology.

关键词： Asymmetric structure Microano functional filler Polymer composite Electromagnetic interference shielding

The Semiclassical Limit in the Quantum Drift-Diffusion Model

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Acta Mathematica Sinica,English Series 2009年第2期25卷 253-264页

作者： qiang chang JU Institute of Applied Physics and Computational Mathematics P. O. Box 8009-28 Beijing 100088 P. R. China

Semiclassical limit to the solution of isentropic quantum drift-diffusion model in semicon- ductor simulation is discussed. It is proved that the semiclassical limit of this solution satisfies the classical drift-diff... 详细信息

关键词： quantum drift-diffusion weak solution semiclassical limit isentropic

Effect of MgO-Cr_(2)O_(3) and Mg0-MgAl_(2)0_(4)-based refractories on refractory-steel interface reaction and cleanliness of pipeline steel

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Journal of Iron and Steel Research(International) 2024年第4期31卷 849-860页

作者： Guang-mei Yang Cheng Yuan chang Liu qiang Wang Guang-qiang Li Yong-shun Zou Ao Huang The State Key Laboratory of Refractories and Metallurgy Wuhan University of Science and TechnologyWuhan 430081HubeiChina Key Laboratory for Ferrous Metallurgy and Resources Utilization of Ministry of Education Wuhan University of Science and TechnologyWuhan 430081HubeiChina

The interaction of MgO-MgAl_(2)O_(4)-based and MgO-Cr_(2)O_(3)-based refractories with X70 molten steel was studied by immersion experiments at 1560℃.The effects of immersion time(30 and 60 min)on the contents of total oxygen(TO),Al,Nb,Si,Mn,and Cr as well as the composition,number density,and size distribution of inclusions in the molten steel were *** influence of the penetration and erosion degree of the molten steel to the refractory on the steel-refractory interface layer was *** results show that,at 1560℃,the MgO-MgAl_(2)O_(4)-based refractory can better control the contents of TO and the composition of molten steel compared with the MgO-Cr_(2)O_(3)-based *** TO content is only 16×10^(-4) wt.%in the molten steel after reacted with the Mg0-MgAl_(2)O_(4)-based refractory at the end point of refining,4 accounting for 11.5%of that reacted with the MgO-Cr_(2)O_(3)-based refractory(139×10^(-4) wt.%).The number density of inclusions is only 14 mm^(-2),and the average size ofinclusions is only 1.31μm,with thelargest proportion of inclusions in 1-2μm(70%).The Al_(2)O_(3)-MnS-CaO complex inclusions in the original steel changed to complex inclusions dominated by Cr-Nb-Mn-S-O and ***_(2)O_(3),corresponding to the MgO-Cr_(2)O_(3)-based and MgO-MgAl_(2)O_(4)-based refractories,*** ***_(2)O_(3) layer was formed at the reaction interface between MgO-MgAl_(2)O_(4)-based refractory and molten steel,which is helpful to restrict the erosion of refractories and the pollution of molten *** damage mechanism of the MgO-Cr_(2)O_(3)-based refractory is mainly permeation and chemical reaction,while the damage of the MgO-MgAl_(2)O_(4)-based refractory is mainlyscouring erosion.

关键词： MgO-Cr_(2)O_(3)-based refractory MgO-MgAl O_(4)-based refractory Nonmetallic inclusion Erosion interface layer Steel penetration

Fracture analysis of rock mass based on 3-D nonlinear Finite Element Method

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Science China(Technological Sciences) 2011年第3期54卷 556-564页

作者： LIU YaoRu chang qiang YANG qiang WANG ChuanQi GUAN FuHai State Key Laboratory of Hydroscience and Hydraulic Engineering Tsinghua University Beijing 100084 China

Traditional fracture analysis is based on fracture mechanics and damage mechanics. They focus on the propagation of the fracture. However, their propagation criterions are not easily applied in practice and the current analysis is limited in planar problem. This paper presents a new theory that the occurrence of the unbalanced force (derived from the Deformation Reinforcement Theory) could be the criterion of the initiation of the fracture, and the distribution area and propagation of the unbalanced force could be the indication of the fracture propagation direction. By aggregate analysis with Stress Intensity Factor (SIF) criterion, the unbalanced force actually is the opposite external load that is the SIF difference incurred between the external loads and permitted by the structure. Numerical simulation and physical experiments on pre-fracture cuboid rock specimens proved that the occurrence of the unbalanced force could be the initiation of the fracture. Mesh size dependence was also considered by analysis of different mesh size finite element gravity dam models. Furthermore, the theory was applied to the feasibility analysis of the Baihetan arch dam together with physical experiments in order to evaluate the fracture propagation of dam heel. The results show that it is an effective way to use unbalanced force to analyze the fracture initiation and propagation when performing 3-dimensional nonlinear FEM calculation.

关键词：三维非线性非线性有限元方法断裂分析有限元分析模型不平衡力岩体应力强度因子裂缝延伸