oalib

Publish in OALib Journal

ISSN: 2333-9721

APC: Only $99

Submit

Any time

2019 ( 19 )

2018 ( 325 )

2017 ( 316 )

2016 ( 313 )

Custom range...

Search Results: 1 - 10 of 13895 matches for " 陶煜 "
All listed articles are free for downloading (OA Articles)
Page 1 /13895
Display every page Item
裂隙岩体渗流-应力耦合等效渗流阻模型
,刘卫群
岩土力学 , 2012,
Abstract: 针对含区域主干裂隙岩体在应力作用下的渗透特性进行了研究。运用单裂隙平行板渗流理论、弹性力学方法,结合模拟电路知识,提出等效渗流阻的概念。在分析裂隙岩体区域中主干裂隙系统几何构造的基础上,建立了基于等效渗流阻的-渗流-应力耦合模型,得到了裂隙岩体等效渗流阻、渗透率与应力之间的关系,从而为研究含区域主干裂隙岩体的应力-渗流耦合规律提供了方便。结合一个基于等效渗流阻模型的算例,考察了含“人”字形组合裂隙试样的渗透特性。经进一步细化后,该模型可用于分析地应力作用下的含区域主干裂隙岩体渗流演化规律。
供应链管理理论与方法
沈厚才, ,
中国管理科学 , 2000,
Abstract: ?进入九十年代以来,供应链管理成为增强企业竞争力最重要方法之一。本文介绍了供应链管理的基本思想,说明了供应链管理产生的理论与现实背景,介绍了实施供应链管理的基本过程,分析了为辅助供应链管理的模型,并说明了供应链管理对我国企业管理的借鉴作用。
基于视觉感知增强的最大密度投影算法
周志光?,波?,林海?
软件学报 , 2013, DOI: 10.3724/SP.J.1001.2013.04223
Abstract: 提出一种基于视觉感知增强的最大密度投影算法,无需调节复杂的传输函数,就可以有效增强体数据内部最大密度特征的深度感知和形状感知.在传统的最大密度投影算法的基础上,利用梯度模属性精确查找特征或相似特征的边界,以确定最佳法向特征;利用最佳法向特征的深度信息自适应地修改局部光照系数,进而对最大密度特征进行光照处理,以获得视觉感知增强的可视化结果;采用基于密度值和三维空间距离的双阈值区域增长策略,动态区分感兴趣区域和背景区域,交互地实现特征突出显示.实验结果表明,该算法在传统算法的基础上进一步增强了最大密度特征的视觉感知,并提供了丰富的形状信息和背景补偿信息,具有较强的实用性.
充填泥沙裂隙岩石渗流特性的实验研究
王甘林,刘卫群,
力学与实践 , 2010, DOI: 10.6052/1000-0992-lxysj2010-050
Abstract: 对人工充填泥沙裂隙岩石在MTS815.02电液伺服岩石试验系统上进行渗流实验,同时结合岩石孔隙电子显微照片,探讨了泥沙颗粒对裂隙岩石渗透特性的影响规律.实验表明,在泥沙颗粒的作用下,裂隙岩样渗透率明显减小;泥沙颗粒在岩样宏观裂隙中运移达到重新平衡之后,裂隙岩样渗透率随时间逐渐增大并最终趋于稳定.
随动曲线坐标能量法模拟平面塑性压缩
永发,,王全成
力学与实践 , 1992, DOI: 10.6052/1000-0992-1992-149
Abstract: 本文给出平面压缩时随动曲线坐标系下运动可能速度场和相应的力学张量表达式.利用电算法优化可变参数使总能量泛函达最小值,从而获得流动速度场、位移场、应变速率和应力场的数值解.描述出不同宽高比时坯料产生单鼓形和双鼓形等现象,计算结果与实验吻合较好.
东亚的梅雨期与亚洲上空大气环流季节变化的关系
诗言?,佳?,陈晓敏?
气象学报 , 1958, DOI: 10.11676/qxxb1958.014
Abstract: 本文根据气候的资料以及1951—1957年的高空资料,对东亚的梅雨期气候特点,以及梅雨期跟亚洲上空大气环流季节变化的关系,作了分析.作者发现,东亚梅雨期的开始和结束是很有规律性的,梅雨期与亚洲上空大气环流的季节变化有着很密切的关系.这个时期是发生在亚洲上空行星风带向北突然推进的时期.东亚梅雨期开始的日期跟印度季风在印度加尔各答建立的日期是相一致的.梅雨期的结束跟日本馆野高空西风急流消失并且东风出现的日期很接近.这种在亚洲上空出现的大气环流季节变化,在年与年之间,虽然在时间上有一些出入,但变化的型式却是一致的.这种现象的揭露,对于东亚梅雨的了解及预报问题是有帮助的.
镧离子对碱性磷酸酶的作用
胡健,,刘湘,李荣昌,王夔
北京大学学报(医学版) , 2003,
Abstract: ?目的:研究la3+对肝型及肠型碱性磷酸酶活性的影响及作用机制.方法:采用磷酸苯二钠法测定酶活性,荧光滴定监测la3+对碱性磷酸酶内源性荧光的影响,由荧光淬灭方程计算la3+在酶分子上的结合数目及结合常数.结果:la3+可以增强肝型碱性磷酸酶的活性,而对肠型碱性磷酸酶有抑制作用.la3+对两种酶反应的动力学参数有不同的影响.发现la3+对肠型碱性磷酸酶的内源性荧光具有淬灭作用,说明la3+的结合可以改变酶分子在溶液中的构象.由荧光淬灭方程,测得la3+与肠型碱性磷酸酶只有一类,约78个结合位点,结合常数为2.1×104.结论:la3+对两种碱性磷酸酶具有不同的作用;la3+通过改变肠型碱性磷酸酶的构象影响其活性.
基于形态分量分析的高速铣削加工刀具磨损在线监测
,朱锟鹏,高思
- , 2017, DOI: 10.3969/j.issn.0253-2778.2017.08.010
Abstract: 在高速铣削加工中,铣刀在超高转速下进行不连续切削,刀具磨损迅速且难以监测,严重影响加工精度和产品质量,因此刀具磨损的状态监测极其重要.振动法是一种有效的刀具状态监测方法,但是振动信号包含了多种振动成分及大量噪声,影响刀具磨损状态监测的准确性.针对该问题,提出了一种利用对偶基追踪算法和用形态分量分析对振动信号进行稀疏分解的方法.首先,分析了高速铣削加工过程中振动信号的形态分量特点和稀疏特性,构造了对偶基追踪框架,通过增广拉格朗日变量分离算法进行求解,实现对振动信号中的脉冲成分和谐波成分的分离.其次,构造并提取了脉冲密度和高次谐波频率与基频的幅值比等特征并利用这些特征进行刀具磨损状态监测.最后,通过仿真分析和实验,验证了该方法的可行性.
Abstract:In high-speed milling, the cutter undergoes ultra-high-speed milling discontinuously, leading to rapid tool wear or breakage, which is difficult to monitor and will seriously affect machining accuracy and product quality, which underscores the importance of tool wear condition monitoring. Although the vibration method is an effective tool condition monitoring method, the vibration signal contains a variety of components and much noise, which decrease the accuracy of tool wear condition monitoring. To solve this problem, a sparse decomposition method of vibration signal was proposed based on the dual basis pursuit algorithm and morphological component analysis. First, morphological and sparse characteristics of the vibration signals in high speed milling were analyzed, and a dual basis pursuit framework was constructed and solved by an augmented Lagrangian variable splitting, thus separating the impulse components and harmonic components. Subsequently, two feature vectors, including the impulse density and amplitude
慢性肾衰竭患者透析起始肾小球滤过率与预后关系的meta分析
田智超△,,胡小红,毛志国
- , 2016, DOI: 10.16781/j.0258-879x.2016.07.0834
Abstract: 目的 通过系统回顾与meta分析方法探讨慢性肾衰竭患者开始透析时的肾小球滤过率(GFR)水平与其预后的关系。方法 以“dialysis initiation” “prognosis/mortality/survival” “timing” “CKD/CRF/ESRD”为关键词,检索PubMed、Medline、EMBASE、Cochrane Central Registry of Controlled Clinical Trials数据库,根据纳入及排除标准选择纳入的文献并进行meta分析。结果 共纳入20篇文献,包含21项研究。总体结果为透析起始GFR每增加1 mL/(min·1.73 m2),患者的全因死亡风险即升高3.3%(HR=1.033,95% CI: 1.026~1.040,P < 0.001)。对纳入的2项随机对照试验、4项各组生存分析起点设置为相同水平的研究分别进行亚组分析,结果均为透析起始GFR与患者生存率无关(HR=1.001,95%CI: 0.983~1.020,P = 0.891;HR=1.014,95%CI: 0.990~1.040,P = 0.260);对以GFR=10或10.5 mL/(min·1.73 m2)为分界点将患者分为早期和晚期两组的3项研究进行亚组分析,结果显示两组生存率差异亦无统计学意义(HR=1.062, 95%CI: 0.691~1.633, P = 0.784)。结论 目前的证据显示,慢性肾衰竭患者透析起始GFR越高,死亡风险越高。但导致患者早期透析的因素较复杂,仍需更多高质量的临床证据来决定合理的透析起始时机。
Objective To investigate the relationship between glomerular filtration rate (GFR) at the initiation of dialysis and the prognosis of chronic renal failure (CRF) patients via systematic review and meta analysis. Methods Literature retrieval was conducted using "dialysis initiation", "prognosis/mortality/survival", "timing", and "CKD/CRF/ESRD" as key words in databases including PubMed, Medline, EMBASE and Cochrane Central Registry of Controlled Clinical Trials. Literatures were selected according to the predefined inclusion and exclusion criteria and the data were analyzed using meta analysis. Results Finally 20 references containing 21 studies were included in the present study. The overall analysis showed that a 1 mL/(min·1.73 m2) GFR increment was associated with a 3.3% increase in all-cause mortality (HR=1.033, 95% CI:1.026-1.040, P < 0.001). However, the subgroup analysis of two RCTs and four studies with the same survival analysis origin demonstrated no significant correlation between GFR at dialysis initiation and survival rate (HR=1.001, 95%CI:0.983-1.020, P = 0.891; HR=1.014, 95%CI:0.990-1.040, P = 0.260). In addition, subgroup analysis including studies with 10 or 10.5 mL/(min·1.73 m2) GFR as the cut-off values between early and late stages also showed no significant differences in the survival rates (HR=1.062, 95%CI:0.691-1.633, P = 0.784). Conclusion It is indicated that higher GFR at dialysis initiation is associated with increased mortality rate of CRF patients; however, the reason for early dialysis is complicated and more high quality clinical trials are needed to determine the dialysis timing
纤维喉镜经口腔诊治下咽部异物的临床体会
Fiber Laryngoscope in Oral and Pharyngeal Foreign Body under the Clinical Experience of
 [PDF]


Asian Case Reports in Otolaryngology (ACRO) , 2013, DOI: 10.12677/ACRO.2013.12004
Abstract:

目的:探讨电视监视纤维喉镜下经口腔诊治下咽部异物的临床应用。方法:分析应用纤维喉镜经口腔诊治下咽部异物所得的197例临床资料。结果:187例患者均顺利取出,成功率94.92%;4例患者未见异物;3例患者因咽反射敏感而拒绝治疗,3例咽侧壁破裂渗血。结论:对纤维喉镜下经口腔诊治下咽部异物临床体会是首先是增加了一种诊治途径,其次是安全准确,并发症少,值得临床推广应用。
To investigate the effect of television watching fiber laryngoscope by the clinical application of oral treatment of pharyngeal foreign body. Methods: The clinical data of 197 cases of application of fiber laryngoscope in oral treatment of pharyngeal foreign body income analysis. Results: 187 patients were successfully removed, the success rate was 94.92%; 4 patients had no foreign body; 3 patients with pharyngeal reflex sensitivity and refuse treat-ment, 3 cases of lateral pharyngeal wall rupture bleeding. Conclusion: The experience of fiber laryngoscope oral treat-ment of throat clinical is first adds a treatment approach, second is safe and accurate, less complications, is worthy of clinical application

Page 1 /13895
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.