期刊文献+
共找到51,710篇文章
< 1 2 250 >
每页显示 20 50 100
Drag reduction of turbulent channel flows over an anisotropic porous wall with reduced spanwise permeability 预览
1
作者 Qingxiang LI Ming PAN +1 位作者 Quan ZHOU Yuhong DONG 《应用数学和力学:英文版》 SCIE EI CSCD 2019年第7期1041-1052,共12页
The direct numerical simulation (DNS) is carried out for the incompressible viscous turbulent flows over an anisotropic porous wall. Effects of the anisotropic porous wall on turbulence modifications as well as on the... The direct numerical simulation (DNS) is carried out for the incompressible viscous turbulent flows over an anisotropic porous wall. Effects of the anisotropic porous wall on turbulence modifications as well as on the turbulent drag reduction are investigated. The simulation is carried out at a friction Reynolds number of 180, which is based on the averaged friction velocity at the interface between the porous medium and the clear fluid domain. The depth of the porous layer ranges from 0.9 to 54 viscous units. The permeability in the spanwise direction is set to be lower than the other directions in the present simulation. The maximum drag reduction obtained is about 15.3% which occurs for a depth of 9 viscous units. The increasing of drag is addressed when the depth of the porous layer is more than 25 wall units. The thinner porous layer restricts the spanwise extension of the streamwise vortices which suppresses the bursting events near the wall. However, for the thicker porous layer, the wall-normal fluctuations are enhanced due to the weakening of the wall-blocking effect which can trigger strong turbulent structures near the wall. 展开更多
关键词 direct numerical simulation (DNS) ANISOTROPIC POROUS medium drag reduction TURBULENT open channel flow
在线阅读 下载PDF
开腹与腹腔镜左半肝切除术对左肝胆管结石治疗对比 预览
2
作者 王家欢 《医学理论与实践》 2019年第16期2510-2512,共3页
目的:探讨比较开腹与腹腔镜左半肝切除术对左肝胆管结石的疗效。方法:选取本院2015年5月—2018年8月收治的分别实施腹腔镜左半肝切除术(治疗组)和开腹左半肝切除术(对照组)的左肝胆管结石患者,各40例,比较两组患者的一般资料、围手术期... 目的:探讨比较开腹与腹腔镜左半肝切除术对左肝胆管结石的疗效。方法:选取本院2015年5月—2018年8月收治的分别实施腹腔镜左半肝切除术(治疗组)和开腹左半肝切除术(对照组)的左肝胆管结石患者,各40例,比较两组患者的一般资料、围手术期资料、临床疗效以及术后并发症情况。结果:两组患者的手术时间差异无统计学意义( P >0.05),治疗组患者的术中出血量、术后ICU时间、住院时间、肛门排气时间以及引流管放置时间都比对照组显著减少( P <0.05)。两组的结石清除率和术后复发率差异无统计学意义( P >0.05)。治疗后,治疗组患者总有效率高达90.0%,与对照组相比显著升高( P <0.05),此外,治疗组的并发症总发生率显著低于对照组( P <0.05)。结论:腹腔镜左半肝切除术治疗左肝胆管结石具有疗效好、恢复快、创伤小、住院时间短、并发症少等优点,且临床疗效和开腹手术一致,具有广泛的临床应用价值。 展开更多
关键词 左半肝切除术 左肝胆管结石 开腹 腹腔镜
在线阅读 免费下载
多次地震动作用下对桥梁圆端空心墩的位移响应研究 预览
3
作者 周博宇 吴永红 +1 位作者 邹大晴 熊丽婷 《土木建筑工程信息技术》 2019年第4期96-103,共8页
实际结构往往遭遇多次地震动作用,而目前国内抗震设计规范考虑的仅为单一地震事件影响,尚无法考虑多次地震动下桥梁结构的响应情况。针对上述现象,作者以秋末河大桥为工程背景,基于抗震分析软件Open Sees对铁路圆端空心墩进行传统及累... 实际结构往往遭遇多次地震动作用,而目前国内抗震设计规范考虑的仅为单一地震事件影响,尚无法考虑多次地震动下桥梁结构的响应情况。针对上述现象,作者以秋末河大桥为工程背景,基于抗震分析软件Open Sees对铁路圆端空心墩进行传统及累积增量动力分析数值模拟,通过对比两种情况下位移响应情况来研究多次地震动的影响。结果表明:1)该铁路圆端空心墩较柔,高阶振型较为明显,结构最大位移及残余位移随峰值加速度的增加而增加;2)较单一地震作用而言,多次地震动下,结构的最大位移及残余位移均偏大;3)两种不同分析方法,对于结构最大位移响应,当结构处于弹性状态,其差异不明显,当结构处于弹塑性状态,其差异较大不可忽略;对于残余位移而言,其差异均较为明显,不可忽略。 展开更多
关键词 抗震设计 秋末河大桥 增量动力分析 OPEN SEES 残余位移
在线阅读 免费下载
慕课传播的特征、模式与反思 预览
4
作者 付静 《传媒》 CSSCI 北大核心 2019年第2期47-48,共2页
MOOC是英文Massive Open Online Course的缩写,简单来讲,就是大规模的开放化在线课程,也就是我们所讲的“慕课”。慕课作为信息技术与教育融合的产物,不仅是一种全新的教育模式,而且是一种全新的信息传播模式,它有效推动了现代教育的创... MOOC是英文Massive Open Online Course的缩写,简单来讲,就是大规模的开放化在线课程,也就是我们所讲的“慕课”。慕课作为信息技术与教育融合的产物,不仅是一种全新的教育模式,而且是一种全新的信息传播模式,它有效推动了现代教育的创新与转型。慕课的产生打破了传统教育理念的框架,对教育发展产生了深远影响,并为知识传播的变革带来了新的可能。2012年,美国首先掀起了慕课风潮,并相继成立了Coursera、Udacity和edX三大代表性慕课平台。2013年,慕课被引入中国,并相继成立了“在线学习联合体”“学堂在线”“中国大学MOOC”“华文慕课”等知名慕课平台,正式拉开了中国慕课传播时代的大幕。但由于起步较晚,慕课传播还存在着许多问题,如何深入挖掘其传播规律,如何实现慕课的本土化创新,这些问题都需要进行重点研究和探讨。基于此,笔者对慕课传播的特征、模式和发展对策进行分析,期望能为慕课传播价值空间的进一步拓展提供些许参考。 展开更多
关键词 信息传播模式 慕课 ONLINE 传统教育理念 中国大学 MOOC OPEN 在线课程
在线阅读 下载PDF
Multiple rare causes of post-traumatic elbow stiffness in an adolescent patient:A case report and review of literature 预览
5
作者 Bai-Qi Pan Jun Huang +2 位作者 Jiang-Dong Ni Ming-Ming Yan Qin Xia 《世界临床病例杂志》 2019年第10期1191-1199,共9页
BACKGROUND Joint stiffness after elbow surgery is not a rare complication,and is always accompanied by deformity.The causes of joint stiffness are multiple in different patients,and divided into intrinsic and extrinsi... BACKGROUND Joint stiffness after elbow surgery is not a rare complication,and is always accompanied by deformity.The causes of joint stiffness are multiple in different patients,and divided into intrinsic and extrinsic causes.Herein,we report an unusual case of posttraumatic elbow stiffness due to multiple and rare causes.CASE SUMMARY A 19-year-old male was hospitalized with the loss of motion of the left elbow for over ten years.Left limb computed tomography revealed left elbow stiffness with bony block and connection.The patient underwent surgery,and the etiology of joint stiffness was found to be a rare combination of common and uncommon causes.During an 18-mo follow-up period,the patient’s left elbow had normal motion and he was symptom-free.CONCLUSION However,this case combined with multiple and rare causes highlights that the patient with scar physique is likely to be accompanied with more severe soft tissue,nerve contracture,and heterotypic ossification,even during recurrence. 展开更多
关键词 POST-TRAUMATIC ELBOW stiffness Open surgery CONTRACTURE ULNAR NEURITIS Radial nerve Scar Case report
在线阅读 免费下载
电梯维保管理平台建设的探讨 预览
6
作者 廖长江 《电子产品可靠性与环境试验》 2019年第A01期123-126,共4页
电梯维保管理平台,采用信息化技术实现了无纸化电梯维保记录及电梯质量安全关键数据的收集与共享。其维保记录格式、内容和要求满足相关法律、法规和安全技术规范的要求,其数据在保存过程中不得有任何程度和任何形式的更改,以确保储存... 电梯维保管理平台,采用信息化技术实现了无纸化电梯维保记录及电梯质量安全关键数据的收集与共享。其维保记录格式、内容和要求满足相关法律、法规和安全技术规范的要求,其数据在保存过程中不得有任何程度和任何形式的更改,以确保储存数据的公正、客观和安全,并可实时进行查询。对电梯维保管理平台的建设进行了探讨,提出了电梯维保管理平台应是一个共享的平台、高效的平台、容易使用的平台、开放的、可持续发展的平台的观点,对于电梯维保管理平台的合理构建,提高电梯的稳定性和安全性具有重要的意义. 展开更多
关键词 电梯维保管理平台 维保地域网格图 共享 高效 容易使用 开放
在线阅读 下载PDF
工科研究生开放式研究型实验教学方法研究与实践 预览 被引量:1
7
作者 张延顺 李明 杨琳 《高教学刊》 2019年第4期11-13,共3页
在卓越工程师教育计划背景下,将多年课堂教学、实验教学和相关科研工作的经验融入到实验教学中,探索培养研究生的开放式、研究型实验教学方法。该方法的主要特点是提供开放式的模块化实验平台,让学生独立设计、完成实验。在实验中,教师... 在卓越工程师教育计划背景下,将多年课堂教学、实验教学和相关科研工作的经验融入到实验教学中,探索培养研究生的开放式、研究型实验教学方法。该方法的主要特点是提供开放式的模块化实验平台,让学生独立设计、完成实验。在实验中,教师由传统的主导角色转变为辅助、引导角色,这种实验教学方法能够实现激发学生热情、导引前沿技术、提供平台和协助完成实验的作用。文章的方法在《惯性导航技术综合实验》课程中进行了教学实践,并起到了较好的效果。 展开更多
关键词 卓越计划 工科研究生 开放式 研究型 教学实践
在线阅读 下载PDF
骨科微创技术对腰椎间盘突出症的疗效及血清炎性因子水平的影响 预览 被引量:1
8
作者 陈林 李波 +6 位作者 冉胜强 吴光宇 刘喜鹏 杨帆 尹航 汪海波 贺仕雄 《贵州医科大学学报》 CAS 2019年第3期369-372,共4页
目的:探讨骨科椎间孔镜对腰椎间盘突出症的疗效及血清炎性因子水平的影响。方法:90例腰椎间盘突出症患者均分为对照组和治疗组,对照组采用开放手术治疗、治疗组采用骨科微创技术治疗;比较两组患者手术时间、住院时间、出血量、疼痛视觉... 目的:探讨骨科椎间孔镜对腰椎间盘突出症的疗效及血清炎性因子水平的影响。方法:90例腰椎间盘突出症患者均分为对照组和治疗组,对照组采用开放手术治疗、治疗组采用骨科微创技术治疗;比较两组患者手术时间、住院时间、出血量、疼痛视觉模拟(VSA)评分及治疗效果,比较术前及术后第1、3及7天时两组患者血清C反应蛋白(CRP)、白介素-1β(IL-1β)、IL-6、IL-8及IL-10水平。结果:治疗组患者平均手术时间、住院时间、出血量及疼痛VSA评分显著低于对照组(P<0.05),手术后第1、3及7天时,两组患者血清CRP、IL-1β、IL-6、IL-8及IL-10水平均显著高于治疗前(P<0.05),对照组显著高于治疗组(P<0.05),且均在术后第3天达到最高;治疗组患者与对照组患者优良率(88.9%、91.1%)比较,差异无统计学意义(P>0.05)。结论:骨科微创手术和传统开放手术治疗腰椎间盘突出症整体疗效基本一致,但微创治疗炎性反应轻微、对患者损伤程度较小、手术恢复时间快。 展开更多
关键词 手术 开放 手术 微创治疗 腰椎间盘突出症 临床疗效 炎性因子
在线阅读 下载PDF
Changes in neurological and pathological outcomes in a modified rat spinal cord injury model with closed canal 预览
9
作者 Xin Sun Xin Sun +5 位作者 Xing-Zhen Liu Jia Wang Hai-Rong Tao Tong Zhu Wen-Jie Jin Kang-Ping Shen 《中国神经再生研究:英文版》 SCIE CAS CSCD 2020年第4期697-704,共8页
Most animal spinal cord injury models involve a laminectomy,such as the weight drop model or the transection model.However,in clinical practice,many patients undergo spinal cord injury while maintaining a relatively c... Most animal spinal cord injury models involve a laminectomy,such as the weight drop model or the transection model.However,in clinical practice,many patients undergo spinal cord injury while maintaining a relatively complete spinal canal.Thus,open spinal cord injury models often do not simulate real injuries,and few previous studies have investigated whether having a closed spinal canal after a primary spinal cord injury may influence secondary processes.Therefore,we aimed to assess the differences in neurological dysfunction and pathological changes between rat spinal cord injury models with closed and open spinal canals.Sprague-Dawley rats were randomly divided into three groups.In the sham group,the tunnel was expanded only,without inserting a screw into the spinal canal.In the spinal cord injury with open canal group,a screw was inserted into the spinal canal to cause spinal cord injury for 5 minutes,and then the screw was pulled out,leaving a hole in the vertebral plate.In the spinal cord injury with closed canal group,after inserting a screw into the spinal canal for 5 minutes,the screw was pulled out by approximately 1.5 mm and the flat end of the screw remained in the hole in the vertebral plate so that the spinal canal remained closed;this group was the modified model,which used a screw both to compress the spinal cord and to seal the spinal canal.At 7 days post-operation,the Basso-Beattie-Bresnahan scale was used to measure changes in neurological outcomes.Hematoxylin-eosin staining was used to assess histopathology.To evaluate the degree of local secondary hypoxia,immunohistochemical staining and western blot assays were applied to detect the expression of hypoxia-inducible factor 1α(HIF-1α)and vascular endothelial growth factor(VEGF).Compared with the spinal cord injury with open canal group,in the closed canal group the Basso-Beattie-Bresnahan scores were lower,cell morphology was more irregular,the percentage of morphologically normal neurons was lower,the percentages of HIF-1α-and VEGF-immunorea 展开更多
关键词 Basso-Beattie-Bresnahan scores closed spinal canal HIF-1α hypoxia MODEL nerve regeneration open spinal canal rat secondary injury spinal cord injury VEGF
在线阅读 下载PDF
The total flow control equations and the characteristics of unsteady gradually varied flow in open channels 预览
10
作者 Shi-he Liu Qian-yi Zhao Qiu-shi Luo 《水动力学研究与进展:英文版》 SCIE EI CSCD 2019年第1期177-185,共9页
Most unsteady channel flows in nature and practical engineering appear as gradually varied ones,and in the free surface,the deformation conforms to the long wave hypothesis.One-dimensional total flow models were usual... Most unsteady channel flows in nature and practical engineering appear as gradually varied ones,and in the free surface,the deformation conforms to the long wave hypothesis.One-dimensional total flow models were usually used to for the numerical simulation of long-term and long-distance reaches to describe the water movements,however,the models lack a clear relationship between the three-dimensional flow field and the total flow field.Moreover,few studies of the variations of the roughness coefficient against the time in unsteady flows were conducted.The following results are obtained through the theoretical analysis and the numerical simulations in this paper.(1) One-dimensional total flow control equations of the unsteady gradually varied flow in open channels are obtained directly from the mathematical model of the viscous fluid motion,and can both reflect the influence of the turbulence and provide an explicit expression of the energy slope term.These equations establish a direct connection between the descriptions of the three-dimensional flow fields and the one-dimensional total flows.(2) Synchronous prototype observation data and planar two-dimensional numerical simulation results are used to extract the one-dimensional total flow information and discuss the total flow characteristics.(3)The orders of magnitude for terms in the total flow motion equation are compared,and the variation of the roughness coefficient against the time is analyzed. 展开更多
关键词 Open CHANNEL UNSTEADY FLOW TOTAL FLOW CHARACTERISTICS control EQUATIONS
在线阅读 下载PDF
马克思文化观视域下的文化自信论 预览
11
作者 周良武 《牡丹江大学学报》 2019年第2期1-4,共4页
文化作为社会意识形态,属于上层建筑的重要组成部分,为经济基础所决定,必须发展经济以增强文化自信;文化发展有其内在规律,具有同物质生产不平衡、不同步性的特点,必须坚持文化创新性发展以增强文化自信;文化发展具有开放性特点,必须坚... 文化作为社会意识形态,属于上层建筑的重要组成部分,为经济基础所决定,必须发展经济以增强文化自信;文化发展有其内在规律,具有同物质生产不平衡、不同步性的特点,必须坚持文化创新性发展以增强文化自信;文化发展具有开放性特点,必须坚持开放包容的原则以增强文化自信;“现实的个人”是马克思历史唯物主义文化观的基本前提和出发点,文化活动是“现实的个人”活动,增强文化自信必须坚持以人为本的原则。 展开更多
关键词 马克思文化观 文化自信 经济基础 开放 以人为本
在线阅读 下载PDF
Arm中国“极术社区”正式发布,打造AIoT开发者之家 预览
12
《中国集成电路》 2019年第8期4-10,共7页
近日,Arm中国正式发布了由其发起的“极术AIoT开发者社区”。该社区由Arm中国携手中国领先的中文技术交流平台思否(SegmentFault)以及Arm中国生态重要合作伙伴开放智能机器(OPEN AI LAb)和移知科技,专门为中国AIoT开发者搭建,旨在为广... 近日,Arm中国正式发布了由其发起的“极术AIoT开发者社区”。该社区由Arm中国携手中国领先的中文技术交流平台思否(SegmentFault)以及Arm中国生态重要合作伙伴开放智能机器(OPEN AI LAb)和移知科技,专门为中国AIoT开发者搭建,旨在为广大的软硬件开发者提供一个自由交流的平台和答疑解惑的渠道,借助强大的Arm全球及中国生态系统资源,助力中国开发者轻松的进入AIoT领域,将更多创意和创新付诸实践,积极应对下一波万亿智能互联技术浪潮所代表的巨大的市场机遇。 展开更多
关键词 智能机器 智能互联 OPEN 开发者 技术浪潮 软硬件开发 技术交流平台 市场机遇
在线阅读 下载PDF
基于开放平台小基站的5G数字室分解决方案 预览
13
作者 方绍湖 李馨 卜斌龙 《电信科学》 2019年第7期69-77,共9页
从5G时代室内覆盖的挑战与趋势进行分析,提出应对该现状的基于开放平台小基站的5G数字室分解决方案,并提出该方案的核心设计要素。基于5G技术可能对于各行各业带来的影响,探讨了5G开放平台小基站对几个典型行业应用的技术赋能研究。
关键词 5G 开放 小基站 数字室分 行业应用 赋能
在线阅读 下载PDF
生物化学课程实验教学改革探索——以信阳农林学院为例 预览 被引量:1
14
作者 王锐丽 王家东 《信阳农林学院学报》 2019年第1期132-134,共3页
本文就信阳农林学院生物化学实验教学现状和存在的问题,初步从精选实验教学内容、实行与常规式教学相结合的开放式实验教学、加强实验团队建设、改革实验考核评定方法等方面对生物化学课程实验教学进行探索性改革,以期提高学生学习积极... 本文就信阳农林学院生物化学实验教学现状和存在的问题,初步从精选实验教学内容、实行与常规式教学相结合的开放式实验教学、加强实验团队建设、改革实验考核评定方法等方面对生物化学课程实验教学进行探索性改革,以期提高学生学习积极性,活跃思维,增强创新能力、动手能力,达到提高实验教学质量和提升学生综合素质的目的。 展开更多
关键词 应用型 本科院校 开放性 实验教学 创新能力
在线阅读 免费下载
Potassium Channel Origami Windmill Model 预览
15
作者 Zuodong Sun 《美中医学:英文版》 2019年第4期170-172,共3页
The potassium channel model proposed in this paper is an independent functional unit,four pore helixes rotating synchronously in one direction;it transports K^+passively and unilaterally and has no dependence on ATP,w... The potassium channel model proposed in this paper is an independent functional unit,four pore helixes rotating synchronously in one direction;it transports K^+passively and unilaterally and has no dependence on ATP,which is different from previous models such as“paddle model”,“propeller model”and“revolving door model”.Its mechanism is that K+and the positively charged amino acids inα-helixs form a repulsive force,which pushes the“blade”back and makes the“windmill”rotate.The aperture size of K^+channel varies with the speed of windmill.This determines the“opening”and“closing”of channel holes.The model of“origami windmill”reveals the mechanism of K^+channel operation by applying the principles of cell biophysics.This has enlightening significance for other basic research related to it.Perhaps,this will help answer the basic biological questions of human health and disease from the source. 展开更多
关键词 K^+channel open CLOSE ORIGAMI WINDMILL MODEL K+transshipment
在线阅读 下载PDF
The effect of multi-orifice plate configuration on bubble detachment volume
16
作者 Jiming Wen Qiunan Sun +1 位作者 Zhongning Sun Haifeng Gu 《中国化学工程学报:英文版》 SCIE EI CAS CSCD 2019年第1期72-84,共13页
The multi-orifice plate gas sparger, mainly composed of a multi-orifice plate and a gas chamber, is one of the most common sparger facilities.The aeration performance of multi-orifice plate has a close relation with t... The multi-orifice plate gas sparger, mainly composed of a multi-orifice plate and a gas chamber, is one of the most common sparger facilities.The aeration performance of multi-orifice plate has a close relation with the multiorifice plate configuration.In addition, the weeping phenomenon has a considerable influence on the gas chamber condition which affects the bubble detachment volume directly.This paper conducts a set of visual experiments to study the influence of multi-orifice configuration and gas chamber condition on the aeration performance of gas sparger.For multi-orifice plate, an improved theoretical model is proposed which considers the wave effect of the previous bubbles generated from adjacent orifices and the variance of the number of active bubbling orifice.A parameter is proposed to evaluate the aeration performance in order to overcome the difficulty caused by the randomness of bubble formation process.The experimental results suggest that the gas chamber filled with water is in favor of large bubble formation.The influence of the pitch of orifice on aeration performance can only be observed in high-restricted case.According to the theoretical model and experimental results, the influences of gas flow rate and the number of open orifices on the aeration performance are analyzed and a design criterion for the number of open orifice is proposed. 展开更多
关键词 Multi-orifice plate AERATION performance BUBBLE DETACHMENT VOLUME The number of open ORIFICES
Pancreatic necrosis: Complications and changing trend of treatment 预览
17
作者 Mamoon Ur Rashid Ishtiaq Hussain +5 位作者 Sundas Jehanzeb Waqas Ullah Saeed Ali Akriti Gupta Jain Neelam Khetpal Sarfraz Ahmad 《世界胃肠外科杂志:英文版(电子版)》 2019年第4期198-217,共20页
Incidence of acute pancreatitis seems to be increasing in the Western countries and has been associated with significantly increased morbidity. Nearly 80% of the patients with acute pancreatitis undergo resolution;som... Incidence of acute pancreatitis seems to be increasing in the Western countries and has been associated with significantly increased morbidity. Nearly 80% of the patients with acute pancreatitis undergo resolution;some develop complications including pancreatic necrosis. Infection of pancreatic necrosis is the leading cause of death in these patients. A significant portion of these patients needs surgical interventions. Traditionally, the “gold standard” procedure has been the open surgical necrosectomy, which is now being completed by the relatively lesser invasive interventions. Minimally invasive surgical (MIS) procedures include endoscopic drainage, percutaneous image-guided catheter drainage, and retroperitoneal drainage. This review article discusses the open and MIS interventions for pancreatic necrosis with each having its own respective benefits and disadvantages are covered. 展开更多
关键词 Pancreatic NECROSIS NECROSECTOMY Open SURGERY MINIMALLY invasive SURGERY COMPLICATIONS TREATMENT Review article
在线阅读 免费下载
数学建模开放创新实验室的建设与探索 预览
18
作者 曹贻鹏 许飞 陈平 《中国现代教育装备》 2019年第19期24-26,30共4页
实验室建设是重要的教学条件建设之一,基于数学建模的开放创新实验室立足实验教学、以数学建模竞赛为牵引,培养学生对复杂问题进行建模、仿真和求解的能力。在人才培养环节,实验室具备了3个层次6个方面的功能模块,能够系统培养学生的创... 实验室建设是重要的教学条件建设之一,基于数学建模的开放创新实验室立足实验教学、以数学建模竞赛为牵引,培养学生对复杂问题进行建模、仿真和求解的能力。在人才培养环节,实验室具备了3个层次6个方面的功能模块,能够系统培养学生的创新、实践精神;在管理方面,以教研室的管理为主,建模俱乐部的管理为辅,系统制订了各项管理制度,有效缓解和规避了管理中出现的问题。 展开更多
关键词 数学建模 开放 创新 实验室
在线阅读 下载PDF
基于语料库的汉语“动词开-名词”与英语“动词open-n”对比研究 预览
19
作者 张琪 《海外英语》 2019年第10期73-75,共3页
文章基于汉英语料库对“开-名词/open-N”构造进行了对比研究,初步得出以下看法:(1)“开”和“open”都以原型义延伸出其他语义范畴,它们有大致相似的隐喻范畴。(2)动词“开”后接的宾语与英语open有较大差异。汉语“开-名构造”比英语... 文章基于汉英语料库对“开-名词/open-N”构造进行了对比研究,初步得出以下看法:(1)“开”和“open”都以原型义延伸出其他语义范畴,它们有大致相似的隐喻范畴。(2)动词“开”后接的宾语与英语open有较大差异。汉语“开-名构造”比英语“open-n构造”更具经济性和灵活性。(3)两个或两个以上词素形成构造,其意义不完全等同于组成成分的意义之和。其组合会形成一个全新的意义。 展开更多
关键词 认知语言学 动名语法构造 意象图式 open
在线阅读 免费下载
The visualization of turbulent coherent structure in open channel flow 预览
20
作者 Xiao-dong Bai Wei Zhang +3 位作者 Qing-he Fang Yong Wang Jin-hai Zheng An-xin Guo 《水动力学研究与进展:英文版》 SCIE EI CSCD 2019年第2期266-273,共8页
Due to its multiscale and multi-layer natures,the coherent structures of turbulent in the open channel flow is complex and difficult to be visualized for understanding its evolution.In this paper,five types of methods... Due to its multiscale and multi-layer natures,the coherent structures of turbulent in the open channel flow is complex and difficult to be visualized for understanding its evolution.In this paper,five types of methods for the vortical structure in the fluids,namely the Q-criterion,the vorticity,the Omega method,the velocity-vorticity correlation structures(VVCS)as well as the most recent Rortex method,are adopted to visualize the turbulent flow in the open channel.With the free surface modelled as a free slip boundary,a direct numerical simulation(DNS)is carried out to study the multi-layered flow structure characteristics under the free surface.The visualization results by the Q-criterion,the vorticity,the Omega method and the Rortex are firstly analyzed.Then the turbulent flow layers near the free surface are identified with corresponding anisotropy indices.Afterwards,the VVCS within various turbulence layers are visualized accordingly.This research indicates that the VVCS can straightforwardly show the geometry information of the cohere nt structures of turbulent in different layers for the ope n channel flow. 展开更多
关键词 Open channel FLOW FLOW VISUALIZATION velocity-vorticity COHERENT structure direct numerical simulation(DNS)
在线阅读 下载PDF
上一页 1 2 250 下一页 到第
使用帮助 返回顶部 意见反馈