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Can the wet suction technique change the efficacy of endoscopic ultrasound-guided fine-needle aspiration for diagnosing autoimmune pancreatitis type 1? A prospective single-arm study 预览
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作者 Mitsuru Sugimoto Tadayuki Takagi +13 位作者 Rei Suzuki Naoki Konno Hiroyuki Asama Yuki Sato Hiroki Irie Ko Watanabe Jun Nakamura Hitomi Kikuchi Mika Takasumi Minami Hashimoto Tsunetaka Kato Takuto Hikichi Kenji Notohara Hiromasa Ohira 《世界临床病例杂志》 2020年第1期88-96,共9页
BACKGROUND Other than surgery,endoscopic ultrasound-guided fine-needle aspiration(EUSFNA)is the only procedure for histologically diagnosing autoimmune pancreatitis(AIP).However,adequate specimens are difficult to obt... BACKGROUND Other than surgery,endoscopic ultrasound-guided fine-needle aspiration(EUSFNA)is the only procedure for histologically diagnosing autoimmune pancreatitis(AIP).However,adequate specimens are difficult to obtain.Recently,more adequate specimens were reported to be obtained with EUS-FNA with a wet suction technique(WEST)than with conventional EUS-FNA.AIM To histologically diagnose AIP by EUS-FNA with a WEST.METHODS Eleven patients with possible type 1 AIP between February 2016 and August 2018 underwent EUS-FNA with a WEST(WEST group),with four punctures by 19 or 22 G needles.As a historical control,23 type 1 AIP patients who underwent no fewer than four punctures with 19 or 22 G needles were enrolled(DRY group).Patient characteristics and histological findings were compared between the two groups.RESULTS Three histopathological factors according to the International Consensus Diagnostic Criteria were significantly greater in the WEST group than the DRY group[lymphoplasmacytic infiltrate without granulocytic infiltration:9(81.8%)vs 6(26.1%),P=0.003,storiform fibrosis:5(45.5%)vs 1(4.3%),P=0.008,abundant(>10 cells/HPF)IgG4-positive cells:7(63.6%)vs 5(21.7%),P=0.026].Level 1 or level 2 histopathological findings were observed more often in the WEST group than in the DRY group[8(72.7%)vs 3(13.0%),P=0.001].CONCLUSION EUS-FNA with a WEST was more successful than standard EUS-FNA in histologically diagnosing AIP. 展开更多
关键词 AUTOIMMUNE pancreatitis Endoscopic ULTRASOUND-GUIDED fine needle ASPIRATION WET SUCTION TECHNIQUE
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煤矿水仓清理机器人研究与设计
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作者 姚贵英 曹梦媛 马嬪 《煤矿机械》 北大核心 2020年第2期4-6,共3页
根据煤矿水仓工况提出一种可自由规划行走路线的清理机器人,并对其结构及液压系统进行设计。机器人及其配套系统可完成水仓清理、筛分、脱水、运输等配套工作,具有一定的实用价值。
关键词 煤矿排水 清理机器人 绞吸
Earth Pressure Distribution and Sand Deformation Around Modified Suction Caissons (MSCs) Under Monotonic Lateral Loading 预览
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作者 LI Da-yong LI Shan-shan +1 位作者 ZHANG Yu-kun CHEN Fu-quan 《中国海洋工程:英文版》 SCIE EI CSCD 2019年第2期198-206,共9页
The modified suction caisson (MSC) is a novel type of foundation for ocean engineering, consisting of a short external closed-top cylinder-shaped structure surrounding the upper part of the regular suction caisson (RS... The modified suction caisson (MSC) is a novel type of foundation for ocean engineering, consisting of a short external closed-top cylinder-shaped structure surrounding the upper part of the regular suction caisson (RSC). The MSC can provide larger lateral bearing capacity and limit the deflection compared with the RSC. Therefore, the MSC can be much more appropriate to use as an offshore wind turbine foundation. Model tests on the MSC in saturated sand subjected to monotonic lateral loading were carried out to investigate the effects of external structure sizes on the sand surface deformation and the earth pressure distribution along the embedded depth. Test results show that the deformation range of the sand surface increases with the increasing width and length of the external structure. The magnitude of sand upheaval around the MSC is smaller than that of the RSC and the sand upheaval value around the MSC in the loading direction decreases with the increasing external structure dimensions. The net earth pressure in the loading direction acting on the internal compartment of the MSC is smaller than that of the RSC at the same embedded depth. The maximum net earth pressure acting on the external structure outer wall in the loading direction is larger than that of the internal compartment, indicating that a considerable amount of the lateral load and moment is resisted by the external skirt structure. 展开更多
关键词 MSC (modified SUCTION caisson) RSC (regular SUCTION caisson) model tests MONOTONIC lateral loading DEFORMATION of SAND surface earth pressure distribution
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Soil Water Characteristic Curve of an Unsaturated Soil under Low Matric Suction Ranges and Different Stress Conditions 预览
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作者 Paul Habasimbi Tomoyoshi Nishimura 《地球科学国际期刊(英文)》 2019年第1期39-56,共18页
Accurate evaluation of unsaturated soil properties is critical for the design of geotechnical and geo-environmental structures such as road pavements, foundations, and earth dams. Water retention activity in soils whi... Accurate evaluation of unsaturated soil properties is critical for the design of geotechnical and geo-environmental structures such as road pavements, foundations, and earth dams. Water retention activity in soils which is used to predict the stability or seepage problems in the ground is one of the key features in unsaturated soil mechanics. Thus, many experimental works have reported on the unsaturated soil properties, and the soil-water characteristic curve (SWCC) test has contributed significantly to the interpretation of matric suction. Since traditional instruments cannot apply stress in SWCC tests, some researchers have developed suction controlled triaxial apparatus, by which SWCC tests are performed under different stress states. Determination of SWCCs under stress conditions similar to those in the field is key for interpretation of the hydro-mechanical behavior of unsaturated soils. This study conducted SWCC tests of unsaturated silt soil in low matric suction ranges under both drying and wetting conditions. The SWCCs were measured under one-dimensional and isotropic confining stresses ranging from 50 to 450 kPa. The micro porous membrane method was used instead of high air entry ceramic disk for controlling relatively low matric suction. The range of matric suction controlled was from 0 to 20 kPa. The study revealed that the measured SWCC in low matric suction ranges seems to be affected by the influence of stress conditions. Isotropic confining stress caused the void structure of the specimen to become dense and consequently, soil moisture flow movement also decreased. The water retention activity was obviously high, and the point regard to air entry value was larger. The study further suggests that the current methods adopted for estimating unsaturated soil properties require further development to take into account the effect of different stress conditions. 展开更多
关键词 SOIL Water Characteristic CURVE SUCTION UNSATURATED SOIL MEMBRANE Technique
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崩岗侵蚀区非饱和花岗岩残积土强度特性试验研究 预览
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作者 罗小艳 扶名福 《水力发电》 北大核心 2019年第1期107-111,共5页
以崩岗侵蚀区花岗岩残积土为研究对象,应用非饱和土三轴仪对重塑花岗岩残积土进行强度特性试验,研究干密度、净围压和基质吸力对应力-应变关系和强度的影响规律,并分析重塑非饱和花岗岩残积土在控制吸力条件下的抗剪强度特性。结果表明... 以崩岗侵蚀区花岗岩残积土为研究对象,应用非饱和土三轴仪对重塑花岗岩残积土进行强度特性试验,研究干密度、净围压和基质吸力对应力-应变关系和强度的影响规律,并分析重塑非饱和花岗岩残积土在控制吸力条件下的抗剪强度特性。结果表明,非饱和花岗岩残积土的应力-应变关系均呈硬化型;在干密度相同时,非饱和土强度随着基质吸力和净围压的增大而增大;在净围压相同条件下,非饱和土强度随着基质吸力和干密度的增大而增大;基质吸力对粘聚力影响较大,基本上呈线性增长关系,而有效内摩擦角受基质吸力的影响较小,几乎可以不计;非饱和重塑花岗岩残积土的强度随着基质吸力和干密度增大而增大,与基质吸力相关的摩擦角较大。 展开更多
关键词 崩岗侵蚀区 非饱和土 花岗岩残积土 基质吸力 三轴试验
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以29G胰岛素注射器抽吸玻璃体水囊的效果观察
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作者 张祎草 常新奇 李松涛 《中华眼外伤职业眼病杂志》 2019年第4期287-290,共4页
目的观察在青光眼手术中以29G一次性胰岛素注射器抽吸玻璃体水囊的效果。方法回顾性研究2016年8月至2018年5月青光眼术前眼压难以控制者68例(74眼)的临床资料,所有患者术中以29G胰岛素注射器行玻璃体水囊抽吸。随访6个月以上。结果视力... 目的观察在青光眼手术中以29G一次性胰岛素注射器抽吸玻璃体水囊的效果。方法回顾性研究2016年8月至2018年5月青光眼术前眼压难以控制者68例(74眼)的临床资料,所有患者术中以29G胰岛素注射器行玻璃体水囊抽吸。随访6个月以上。结果视力≥0.1者术前为35(47.3%),术后7d为57眼(77.0%)。平均眼压(Goldmann)术后各时间点均较术前降低,差异均具有统计学意义(均P<0.01)。术后7d前房深度均较术前增加,差异有统计学意义(t=30.52,P=0.00)。术中、术后均未出现玻璃体积血或脉络膜爆发性出血等严重并发症。结论以29G胰岛素注射器抽吸玻璃体水囊操作安全、有效、简便且可重复。 展开更多
关键词 注射器 胰岛素 29G 抽吸 水囊 玻璃体 青光眼 小梁切除术
Experimental studies on curling development of artificial soils 预览
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作者 Duaa Al-Jeznawi Marcelo Sanchez +1 位作者 Abbas J.Al-Taie Marcin Zielinski 《岩石力学与岩土工程学报:英文版》 CSCD 2019年第6期1264-1273,共10页
Soil curling is an important phenomenon associated with volume changes induced by increasing soil suction upon desiccation.The study of soil behaviors associated with drying in soils(e.g.soil shrinkage,desiccation cra... Soil curling is an important phenomenon associated with volume changes induced by increasing soil suction upon desiccation.The study of soil behaviors associated with drying in soils(e.g.soil shrinkage,desiccation cracks and curling)has received increasing attention over the last few years,which has been mainly driven by the forecast climate change that will warm up our planet.There are significant gaps in the current knowledge related to the factors that control the development of curling deformations in soils.For this,the curling phenomenon is investigated through laboratory desiccation tests on different mixtures of artificial soils.The effects of soil grain size distribution,mineralogy,soil microstructure,and soil water content on the curling deformation are analyzed.Digital photos were taken at regular time intervals during the tests to understand the volume changes in the soil samples during drying.It is found that soil fabric and soil water content have significant effects on curling scenario.It is observed that the percentage of sand particles and the initial water content play a critical role in the development of soil curling.Samples of pure clayey minerals experienced shrinkage without or with minor curling during drying. 展开更多
关键词 CURLING SHRINKAGE DESICCATION CRACKING SEDIMENTATION SUCTION Thin soil layers
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偏高岭土协同石灰抑制红黏土收缩的行为与机制 被引量:1
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作者 谈云志 胡焱 +3 位作者 邓永锋 曹玲 左清军 明华军 《岩土力学》 EI CAS CSCD 北大核心 2019年第11期4213-4219,共7页
红黏土失水易收缩开裂而诱发工程灾害,为抑制或缓减红黏土的收缩特征,添加4%偏高岭土和5%石灰改善其水敏性。按照最优含水率制备压实试样,养护180 d后抽真空饱和,脱湿到预定含水率,随后开展收缩、无侧限抗压强度、吸力和孔隙分析等试验... 红黏土失水易收缩开裂而诱发工程灾害,为抑制或缓减红黏土的收缩特征,添加4%偏高岭土和5%石灰改善其水敏性。按照最优含水率制备压实试样,养护180 d后抽真空饱和,脱湿到预定含水率,随后开展收缩、无侧限抗压强度、吸力和孔隙分析等试验。结果表明,压实红黏土随着含水率降低,其无侧限抗压强度呈现先增大后减少的变化规律,这是脱湿导致的红黏土衍生微裂隙,进而引起结构性损伤所致。红黏土掺入石灰,尤其是掺入石灰-偏高岭土后,虽然脱湿也会引起强度减小,但接近完全干燥时,其强度又会增大。由此说明,偏高岭土协同石灰可以更加有效地抑制红黏土收缩效应,提高其整体强度。究其原因,是偏高岭土含有大量无定形硅、铝氧化物,且呈现边-面"搭接"的独特结构形态,使其能够快速捕获氢氧化钙溶液中的钙离子,在红黏土团(颗)粒间形成了胶结性水化物。 展开更多
关键词 红黏土 偏高岭土 收缩 微裂隙 吸力
急性心肌梗死行PCI术患者联合血栓抽吸与替罗非班治疗的疗效及对cTnT水平的影响 预览
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作者 汤瑜 《心血管康复医学杂志》 CAS 2019年第2期184-188,共5页
目的:探讨重症急性心肌梗死(AMI)行皮冠脉介入治疗(PCI)患者联合应用血栓抽吸及替罗非班治疗的效果及对心肌肌钙蛋白T(cTnT)水平的影响。方法:我院ICU治疗的AMI患者108例,随机分为单纯PCI组和联合治疗组(PCI术中接受血栓抽吸联合替罗非... 目的:探讨重症急性心肌梗死(AMI)行皮冠脉介入治疗(PCI)患者联合应用血栓抽吸及替罗非班治疗的效果及对心肌肌钙蛋白T(cTnT)水平的影响。方法:我院ICU治疗的AMI患者108例,随机分为单纯PCI组和联合治疗组(PCI术中接受血栓抽吸联合替罗非班),各54例,比较两组的治疗效果及血清cTnT水平变化。结果:与单纯PCI组比较,联合治疗组术后90 min的TIMI血流改善率(77.78%比94.44%)和ST段回落率(72.22%比90.74%)均显著提高(P均<0.05);术后30d的左室射血分数[(46.34±0.53)%比(53.41±0.32)%]显著提高,左室舒张末期内径显著减小[(6.02±0.32)cm比(5.34±0.22)cm],3个月内MACE发生率(20.37%比3.70%)显著降低,P均<0.01;术后3d,两组血清cTnT水平均较术前显著降低,且联合治疗组cTnT水平显著低于单纯PCI组[(0.19±0.05)ng/ml比(0.32±0.03)ng/ml],P=0.001。结论:重症急性心肌梗死患者PCI术中联合应用血栓抽吸及替罗非班治疗,可显著改善患者梗死相关动脉血流及心功能,减轻心肌损伤程度,降低MACE发生率。 展开更多
关键词 心肌梗死 血管成形术 气囊 冠状动脉 抽吸 替罗非班
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泵轮式混合澄清槽混合室单相流的CFD模拟 预览
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作者 刘继连 纪雷鸣 李少伟 《湿法冶金》 CAS 北大核心 2019年第3期249-253,共5页
采用有限元软件Fluent对泵轮式混合澄清槽混合室内的单相流进行数值计算,以雷诺应力模型作为基本方程,模拟混合室内单相流动。通过分析混合室内单相流的速度矢量图、压力云图确定泵轮抽吸高度、泵轮循环流量等参数。结果表明:混合室泵... 采用有限元软件Fluent对泵轮式混合澄清槽混合室内的单相流进行数值计算,以雷诺应力模型作为基本方程,模拟混合室内单相流动。通过分析混合室内单相流的速度矢量图、压力云图确定泵轮抽吸高度、泵轮循环流量等参数。结果表明:混合室泵轮区域及附近存在较大的流体循环,混合作用主要发生在泵轮及其下部的一个较小的范围内;泵轮中心区域和吸液管内的压力明显低于周围混合室压力,从而形成泵轮的抽吸作用;泵轮抽吸高度模拟结果略大于试验结果,经过矫正与试验结果吻合很好,证明了模拟结果的可靠性。 展开更多
关键词 混合澄清槽 泵轮 抽吸 湍动能 数值计算
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Upper Bound Solutions for Uplift Ultimate Bearing Capacity of Suction Caisson Foundation 预览
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作者 DAI Guo-liang ZHU Wen-bo +2 位作者 ZHAI Qian GONG Wei-ming ZHAO Xue-liang 《中国海洋工程:英文版》 SCIE EI CSCD 2019年第6期685-693,共9页
Suction caisson foundation derives most of their uplift resistance from passive suction developed during the pullout movement. It was observed that the passive suction generated in soil at the bottom of the caisson an... Suction caisson foundation derives most of their uplift resistance from passive suction developed during the pullout movement. It was observed that the passive suction generated in soil at the bottom of the caisson and the failure mode of suction caisson foundation subjecting pullout loading behaves as a reverse compression failure mechanism.The upper bound theorems have been proved to be a powerful method to find the critical failure mechanism and critical load associated with foundations, buried caissons and other geotechnical structures. However, limited attempts have been reported to estimate the uplift bearing capacity of the suction caisson foundation using the upper bound solution. In this paper, both reverse failure mechanisms from Prandtl and Hill were adopted as the failure mechanisms for the computation of the uplift bearing capacity of the suction caisson. New equations were proposed based on both failure mechanisms to estimate the pullout capacity of the suction caisson. The proposed equations were verified by the test results and experimental data from published literature. And the two solutions agree reasonably well with the other test results. It can be proved that both failure mechanisms are reasonably and more consistent with the actual force condition. 展开更多
关键词 SUCTION CAISSON FOUNDATION bearing capacity UPPER BOUND solution failure mechanism
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基于孔隙水赋存状态的非饱和土吸力量测分析 预览
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作者 李彦龙 张小辉 《西安建筑科技大学学报:自然科学版》 北大核心 2019年第3期362-368,共7页
非饱和土中孔隙水在不同含水量条件下的赋存状态各异,孔隙水的赋存状态随着土体含水量的增加可分为结合水状态、毛细角边水状态和毛细水连通状态.由不同类型的孔隙水所引起吸力的机理各不相同,对应于孔隙水的3种赋存状态,吸力可分为吸... 非饱和土中孔隙水在不同含水量条件下的赋存状态各异,孔隙水的赋存状态随着土体含水量的增加可分为结合水状态、毛细角边水状态和毛细水连通状态.由不同类型的孔隙水所引起吸力的机理各不相同,对应于孔隙水的3种赋存状态,吸力可分为吸附作用力、吸附—毛细作用力和毛细作用力.吸附作用力可通过等温吸附试验确定,其试验原理和试验结果均较为明确.毛细作用力的计算原理虽较为明确,由于参数取值的困难致使难以通过理论计算获得准确的结果,但可通过高进气值材料测量.分析认为高进气材料较为适合量测毛细作用力,对高进气值材料不恰当的使用是造成土水特征曲线在低含水量段迅速上扬的主要原因.吸附—毛细作用力尚难以通过理论计算或试验获得准确的结果,该吸力在数值上介于吸附作用力和毛细作用力之间. 展开更多
关键词 非饱和土 孔隙水 吸力
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微创抽吸与黄金微针治疗腋臭术后复发患者的疗效观察 预览 被引量:1
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作者 熊文龙 张良 《中国美容医学》 CAS 2019年第5期110-112,共3页
目的:探讨微创抽吸与黄金微针治疗腋臭术后复发的临床疗效。方法:应用微创抽吸治疗复发腋臭30例,应用黄金微针治疗28例,术后随访12个月,观察疗效及并发症发生情况。结果:术后随访12个月,微创抽吸组治疗有效率为93.3%(28/30),黄金微针组... 目的:探讨微创抽吸与黄金微针治疗腋臭术后复发的临床疗效。方法:应用微创抽吸治疗复发腋臭30例,应用黄金微针治疗28例,术后随访12个月,观察疗效及并发症发生情况。结果:术后随访12个月,微创抽吸组治疗有效率为93.3%(28/30),黄金微针组治疗有效率为89.3%(25/28),组间比较差异无统计学意义(P>0.05);两组均无严重并发症发生。结论:微创抽吸与黄金微针治疗腋臭术后复发患者,均有较满意的临床疗效,并发症发生率低,值得临床推广。 展开更多
关键词 微创治疗 抽吸术 黄金微针 腋臭 复发
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肺炎患儿咽部吸出物检测及细菌耐药性探析 预览
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作者 吴雅云 张伟 +1 位作者 陈胜利 谢玲 《药品评价》 CAS 2019年第16期68-69,共2页
目的:探究肺炎患儿咽部吸出物检测及细菌耐药性。方法:选取2015年12月至2018年12月间我院收治肺炎小儿1000例进行实验研究,全部患儿均采用无菌负压吸引法收集患儿新鲜痰液,并进行细菌培养,细菌检测方法为细菌用纸片扩散法,简称为(K-B法... 目的:探究肺炎患儿咽部吸出物检测及细菌耐药性。方法:选取2015年12月至2018年12月间我院收治肺炎小儿1000例进行实验研究,全部患儿均采用无菌负压吸引法收集患儿新鲜痰液,并进行细菌培养,细菌检测方法为细菌用纸片扩散法,简称为(K-B法)以及肉汤稀释法,对患儿的耐药性进行有效分析,为患儿的临床用药提供依据。结果:1000份痰液标本中,阳性率为71.60%;革兰阳性均为368株,占比为51.11%;革兰阴性菌为352株,占比为48.89%;肺炎链球菌对左氧氟沙星、万古霉素药物不存在耐药性,耐药率为0.00%,阿奇霉素耐药性极高,可达100.0%,金黄色葡萄球菌对左氧氟沙星、万古霉素药物不存在耐药性,耐药率为0.00%,阿奇霉素耐药性极高,可达100.0%,肺炎克雷伯菌对复方新诺明、头孢噻肟、阿莫西林耐药性极高,可达90.00%以上,大肠埃希菌阿莫西林、头孢噻肟耐药性极高,可达95.00%以上,流感嗜血杆菌对复方新诺明耐药性极高,可达97.37%,美罗培南对肺炎克雷伯菌、大肠埃希菌、流感嗜血杆菌的药物敏感性极高,可达100.0%。结论:感染肺炎的小儿以肺炎链球菌为主,其次为肺炎克雷伯菌,大肠埃希菌等,应根据患儿所感染疾病菌种,给予患儿针对性治疗,可促进患儿临床合理用药,可降低患儿的产生耐药性,对促进肺炎患儿康复有着重要意义。 展开更多
关键词 肺炎平 咽部 吸出物 细菌耐药性
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Seasonal influence on cone penetration test:An unsaturated soil site example 预览
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作者 Heraldo Luiz Giacheti Renan Cravera Bezerra +1 位作者 Breno Padovezi Rocha Roger Augusto Rodrigues 《岩石力学与岩土工程学报:英文版》 CSCD 2019年第2期361-368,共8页
Interpretation of electric cone penetration test(CPT)based pore water pressure measurement(CPTu)is well established for soils with behavior that follows classical soil mechanics.The literature on the interpretation of... Interpretation of electric cone penetration test(CPT)based pore water pressure measurement(CPTu)is well established for soils with behavior that follows classical soil mechanics.The literature on the interpretation of these tests performed on unsaturated tropical soils is limited,and little is known about the influence of soil suction on in situ test data.In this context,the CPT data are presented and discussed to illustrate the seasonal variability in an unsaturated tropical soil site.The test data show that soil suction significantly influenced CPT data up to a depth of 4 m at the study site.It shows the importance of considering seasonal variability in unsaturated soil sites caused by soil suction,which was related to water content through a soil-water retention curve(SWRC).It is also important to consider this aspect in the interpretation of CPT data from these soils. 展开更多
关键词 SITE investigation In SITU testing Cone penetration test(CPT) UNSATURATED soil SUCTION Variability
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饱和软黏土中开孔防沉板基础上拔特性研究
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作者 刘润 孔金鹏 +1 位作者 刘孟孟 汪嘉钰 《岩土工程学报》 EI CAS CSCD 北大核心 2019年第8期1427-1434,共8页
在软黏土地基中,开孔能有效降低防沉板基础上拔阻力,减小防沉板基础回收难度。对6种具有不同开孔形式的防沉板模型进行了饱和软黏土中的上拔试验,测定了上拔过程中防沉板与土体接触面间的吸附力,揭示了上拔阻力的构成与发展规律,阐明了... 在软黏土地基中,开孔能有效降低防沉板基础上拔阻力,减小防沉板基础回收难度。对6种具有不同开孔形式的防沉板模型进行了饱和软黏土中的上拔试验,测定了上拔过程中防沉板与土体接触面间的吸附力,揭示了上拔阻力的构成与发展规律,阐明了开孔率和有效宽度对上拔阻力和接触面间吸附力的影响规律。采用有限元方法模拟了防沉板基础的上拔过程,建立了上拔力作用下饱和软黏土地基的破坏模式,构建了采用极限分析法计算防沉板上拔阻力的机动场,推导了上拔阻力的上限解,得到了可以同时考虑防沉板开孔率和有效宽度的上拔阻力系数Nc的计算公式。对比验证结果表明:与Skempton公式不同,求解的上拔阻力随开孔率的增加呈非线性降低规律。 展开更多
关键词 防沉板基础 开孔率 有效宽度 饱和软黏土 上拔阻力 吸附力
Influence of root suction on tensile strength of Chrysopogon zizanioides roots and its implication on bioslope stabilization
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作者 Krairoj MAHANNOPKUL Apiniti JOTISANKASA 《山地科学学报:英文版》 SCIE CSCD 2019年第2期275-284,共10页
Root tensile strength is an important factor controlling the performance of bio-slope stabilization works. Due to evapotranspiration and climate factors, the root moisture content and its suction can vary seasonally i... Root tensile strength is an important factor controlling the performance of bio-slope stabilization works. Due to evapotranspiration and climate factors, the root moisture content and its suction can vary seasonally in practice and may not equal soil suction. The influences of suction and root moisture contents were investigated on Chrysopogon zizanioides(vetiver grass) root tensile strength. The root specimens were equilibrated with moist air in different suction conditions(0, 10, 20, and 50 kPa), prior to root tension tests. The root-water characteristic curve or relationship between root moisture and suction, was determined. The increase in suction resulted in decreased tensile strengths of the grass roots, particularly those with diameter of about 0.2 mm, which constituted 50.7% of all roots. For 1 mm roots, the tensile strength appeared to be unaffected by suction increase. The average root tensile strengths were used to estimate the root cohesion in slope stability analysis to find variation of safety factors of a bioengineered slope in different suction conditions. The analysis showed that the critical condition of slope with the lowest factor of safety would happen when the soil suction was zero and the root suction was high. Such condition may occur during a heavy rain period after a prolonged drought. 展开更多
关键词 ROOT tensile strength Bio-slope stabilization SUCTION Vetiver Chrysopogon zizanioides ROOT REINFORCEMENT
对机动车车身附件的多种附着方式的探讨 预览
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作者 赵嘉琦 蒋敏隆 《汽车实用技术》 2019年第12期68-69,共2页
在机动车车身上,附件存在多种可能的附着方式。对文章针对真空吸盘吸附和配合纳米孔面材料的磁性吸附这两种方法进行探讨。
关键词 附着 吸附式 磁性
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OCTA观察高度近视眼行SMILE与FS-LASIK后浅层视网膜血流密度的变化
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作者 李玉 杨文利 张丰菊 《中华眼视光学与视觉科学杂志》 CAS CSCD 2019年第6期401-407,共7页
目的:利用光学相干断层扫描血管成像技术(OCTA)对比飞秒激光小切口角膜基质透镜取出术(SMILE)与飞秒激光制瓣准分子激光原位角膜磨镶术(FS-LASIK)术中负压吸引对浅层视网膜血流密度、视网膜厚度和视网膜神经纤维层的影响。方法:前瞻性... 目的:利用光学相干断层扫描血管成像技术(OCTA)对比飞秒激光小切口角膜基质透镜取出术(SMILE)与飞秒激光制瓣准分子激光原位角膜磨镶术(FS-LASIK)术中负压吸引对浅层视网膜血流密度、视网膜厚度和视网膜神经纤维层的影响。方法:前瞻性非随机对照研究。选取2017年11月至2018年3月于首都医科大学附属北京同仁医院屈光手术中心就诊且双眼等效球镜度(SE)<-6.00D患者(45例)。根据手术方式不同分为FS-LASIK组22例(22眼),SE为(-8.10±1.20)D,SMILE组23例(23眼),SE为(-7.34±1.90)D。所有患者除行常规检查外,由同一人进行术前、术后1周、术后1个月、术后3个月OCTA检查。应用重复测量方差分析、独立样本t检验对数据进行分析。结果:术后3个月时,FS-LASIK组和SMILE组裸眼视力均达到术前最佳矫正视力,SE分别为(0.14±0.82)D和(-0.23±0.56)D,差异无统计学意义(t=1.696,P=0.098)。FS-LASIK组和SMILE组术前浅层视网膜血流密度、视网膜厚度和视盘旁视网膜神经纤维层厚度差异无统计学意义(均P>0.05),且术后1周、术后1个月、3个月2组间比较差异无统计学意义(均P>0.05)。结论:FS-LASIK和SMILE术中负压吸引对高度近视眼底微结构无显著影响。高度近视眼选择2种手术方式均是安全可行的。 展开更多
关键词 飞秒激光小切口角膜基质透镜取出术 准分子激光原位角膜磨镶术 负压 光学相干断层扫描血管成像技术 视网膜血流密度
超声速边界层中壁面抽吸对流动分离的抑制作用 预览
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作者 董明 赵慧勇 《气体物理》 2019年第2期17-29,共13页
当超声速或高超声速来流经过压缩折角时,由于壁面的位移效应,折角附近往往出现较强的逆压梯度,进而很可能导致流动分离,并伴随着激波与边界层干扰问题的出现.在工程应用中,流动分离会带来诸多不利因素.一个抑制流动分离的有效措施是在... 当超声速或高超声速来流经过压缩折角时,由于壁面的位移效应,折角附近往往出现较强的逆压梯度,进而很可能导致流动分离,并伴随着激波与边界层干扰问题的出现.在工程应用中,流动分离会带来诸多不利因素.一个抑制流动分离的有效措施是在折角的上游引入定常的壁面抽吸单元.基于大Reynolds数渐近理论框架下的三层结构理论,文章研究了壁面抽吸抑制层流边界层分离的机理.研究发现,只要抽吸元被安置在折角上游O(R-3/8L)范围内,决定抑制效果的关键参数是抽吸的流量,而与抽吸元的位置无关;同时改变抽吸元的宽度和抽吸速度而保持抽吸流量不变并不影响其对分离区的抑制效果. 展开更多
关键词 超声速边界层 抽吸 分离 压缩折角 三层结构
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