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Search Results: 1 - 10 of 72021 matches for " 罗雁云 "
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城市高架轨道多层隔振系统影响参数匹配
刘艳,
- , 2018, DOI: 10.11908/j.issn.0253-374x.2018.11.008
Abstract: 以轨道交通30 m双线混凝土简支箱梁桥为研究对象,考虑扣件轨道板支承桥梁支座多层隔振系统内部耦合机理,建立车轨桥有限元模型(FEM).通过现场试验数据验证模型有效性.利用该模型展开多工况计算分析,研究各层隔振元件刚度的改变对车体、轨道结构、桥梁结构振动响应特性和综合隔振效果的影响规律,获取参数匹配原则.结果表明:高架轨道各层隔振元件宜采用匹配设计,可在改善沿线环境隔振效果的同时,兼顾车轨桥各层子系统动力响应特性.
By taking two simply supported box girder bridges of 30 m as example, a systematic dynamic simulation model of vehicle track bridge was established, with a consideration of the coupling mechanism of multi layer vibration isolation system. The finite element model(FEM) was verified by a set of field tests. Good agreement between measurement and predicted results proved the effectiveness and accuracy of the model. With the validated simulation model, the effect of resilient parameters on the dynamic response of vehicle, track, slab, bridge wing plate, web plate, bottom plate and bridge pier, was obtained. Finally, parameter matching principle was presented. The results indicate that an optimized elastic parameters matching design of viaducts may improve the isolation efficiency for the vibration environment along railway lines, and ameliorate the dynamic properties of each substructure of vehicle rail bridge systems
不同品牌不透明层厚度与色度的研究
,楼北,孙俊,巢永烈
华西口腔医学杂志 , 2006,
Abstract: 目的研究不同品牌不透明层的厚度对修复体颜色的影响。方法220片镍-铬合金样品片平均分为VITA组、SHOFO组、CARAT组和EXCELCO组4大组,分别上相应品牌的不透明瓷层,各大组中再按瓷层厚度分别分为1、2、3、4、5小组,每小组11片。瓷层厚度用薄层胶纸片形成涂塑模具进行控制。使用TC-PⅡG型全自动测色色差计测定样品片的x、y、△L*值,研究不同品牌不透明层厚度与色度的关系。结果试片明度随不透明层的增厚呈增亮趋势,并趋向稳定在某一厚度值而不再增加,该厚度值在不同品牌间有所不同,其中CARAT系列明度变化最小;而样本色度也随不透明层的增厚逐渐稳定,到达一特定厚度时可完全遮盖底层金属色。结论不透明层在达到一特定厚度时可完全遮盖底层金属色,其中CARAT组的这一厚度值最小,遮色能力相对较强。
城轨高架环境噪声特性与不同频段能量
Characteristics and energies in different frequency bands of environmental noise in urban elevated rail

李莉,尹铁锋,朱茜,
- , 2018,
Abstract: 测试了某城市地铁1号线一期高架线路普通整体道床无声屏障和道床垫式浮置板道床全声屏障区段的桥侧环境噪声,分析了桥侧各测点的A计权总声压级与1/3频程线性声压级,绘制了线性声压级云图,研究了各频段噪声能量比例。分析结果表明:道床垫式浮置板道床全声屏障能有效降低噪声源强处与桥侧环境噪声,降噪效果、能量分布与频段和测点位置有关; 在桥面高度相近的测点,降噪效果随距线路中心线距离的增大而减小,而在近地面的测点,降噪效果随距线路中心线距离的增大而增大; 降噪效果在中高频段明显大于低频段; 在1/3频程中心频率为20.0~31.5 Hz时,距离线路中心线55.0 m处,道床垫式浮置板道床全声屏障区段的线性声压级较普通整体道床无声屏障区段大0.82~6.96 dB; 在普通整体道床无声屏障区段,在高出地面1.2、9.8 m处,噪声能量以低于200 Hz为主,在高出地面11.3 m处,噪声能量以250~400 Hz为主,在高出地面12.8 m处,噪声能量以400~1 000 Hz为主; 在高出地面11.3 m处与200 Hz以下范围内,普通整体道床无声屏障和道床垫式浮置板道床全声屏障区段的噪声能量持平; 在道床垫式浮置板道床全声屏障区段,低于200 Hz的桥侧噪声能量较高,因此,建议根据高架桥旁敏感点的具体位置采取针对性减振降噪措施,并重点关注低频噪声失去中高频噪声的遮蔽后尤显突出的问题。
The environmental noises of bridge side of the first stage elevated line of Metro Line 1 in a city were compared and tested, where the common monolithic track beds without sound barrier and the slab mat track bed with closed sound barrier were used separately. The A-weighted total sound pressure level and 1/3 octave linear sound pressure level of each measuring point on the bridge side were analyzed. The linear sound pressure level cloud diagrams were plotted. Noise energy ratio in each frequency band was studied. Analysis result shows that the slab mat track bed with closed sound barrier can effectively reduce the noise at the noise source strength point and the environmental noise on the bridge side. The noise reduction effect and energy distribution are related to the locations of frequency band and measuring point. At measuring points of similar bridge height, the noise reduction effect decreases with the increase of the distance from the centerline of line, while the noise reduction effect at the near-ground point increases with the increase of the distance from the centerline of line. The noise reduction effect of slab track mattress with closed sound barrier is significantly higher in mid-high frequency range than in low frequency range. When the center frequency of the 1/3 octave is 20.0-31.5 Hz, 55.0 m away from the centerline of line, the linear sound pressure level of slab mat track bed with closed sound barrier is 0.82-6.96 dB higher than that of common monolithic track bed without sound barrier. In the section of common monolithic track bed without sound barrier, the noise energy is mainly below 200 Hz above the ground of 1.2 and 9.8 m, in 250-400 Hz above the ground of 11.3 m, in 400-1 000 Hz above the ground of 12.8 m. Above the ground of 11.3 m, below 200 Hz, the noise energies are nearly equal between the common monolithic track bed without sound barrier and the slab mat track bed with closed sound barrier. In the slab mat track bed area with
不同色号体瓷材料等量混色的研究
楼北,张彦,,孙俊,巢永烈
华西口腔医学杂志 , 2007,
Abstract: 目的探索陶瓷材料颜色匹配中色调变化及明度变化的规律。方法制作镍铬合金片15片,于其上烧结不同色号的VINTAGE系列套装瓷粉,样本组的瓷样本依次由A1和A2、A2和A3、A3和A4、B1和B2、B2和B3、B3和B4色号的瓷粉按体积比等量混色后烧结而成;对照组瓷样本则依次由A1、A2、A3、A3.5、A4、B1、B2、B3、B4色号的瓷粉烧结而成。在PR650分光光度仪上对瓷样本行色度学测试,利用PhotoResearch颜色分析软件进行色度学参数分析。结果相同色系不同色号瓷样本的L*a*b*值有统计学差异(P<0.05),不同色号陶瓷材料等量混色后其色度学参数a*、b*值的变化是一种非线性关系,这种颜色的改变可为人眼辨别。结论VINTAGE系列套装瓷粉中A色系的明度变化梯度大于B色系;相同色系不同色号等量混色时,2号色和3号色的明度梯度最大;A色系红-绿变化明显,B色系黄蓝-变化明显。
分割式可摘局部义齿的制作与临床应用
,王敏,楼北,赖锐,鲁喆
华西口腔医学杂志 , 2006,
Abstract: 目的探讨分割式可摘局部义齿的制作方法和临床应用效果。方法分割式可摘局部义齿由双层基托组成,下层基托与口腔牙槽嵴、黏膜紧密接触,附有义齿,起承力作用;上层基托设计卡环,起固位、卡抱作用,维持义齿的稳定。选择15例KenneyⅢ类患者采用该方法进行义齿修复,3年后复查,观察基牙松动情况,并通过问卷调查了解患者对义齿的咬合情况、固位稳定性和舒适度的满意率。结果15例患者的56颗基牙中,38颗正常,18颗Ⅰ°—Ⅱ°松动。3年后正常基牙存留率为100%,松动基牙存留率为83.3%。3年后15例患者对义齿的咬合情况、固位稳定性和舒适度的满意率分别为73%、60%和73%。结论分割式可摘局部义齿能较好地满足患者对美观和咀嚼功能的要求,并对松动基牙的影响不大,适用于口腔状况欠佳或基牙有Ⅰ°—Ⅱ°松动的患者。
VINTAGE和UNIBOND技工标准比色板颜色间隔的研究
,赖锐,楼北,王敏,巢永烈
华西口腔医学杂志 , 2004,
Abstract: 目的 探讨VINTAGE和UNIBOND技工标准比色板的颜色间隔,确定人眼在比色板各色号间的可辨色数目。方法 利用分光光度仪,测量各色号的色度学参数,计算出相邻各色号间的色差值,再除以人在牙色范围内的最小辨色能力,得到人眼在VINTAGE和UNIBOND技工标准比色板各相邻色号间能分辨的颜色数。结果 VIN-TAGE和UNIBOND技工标准比色板各相邻色号间人眼可分辨的颜色数为3~6个。B色号的颜色间隔较大,D色号的颜色间隔较小;高明度区域的色号颜色间隔较大,低明度区域色号颜色间隔较小。结论 VINTAGE和UNIBOND技工标准比色板各色号间存在着一定的颜色间隔,临床比色工作中不能完全依靠比色板进行牙色的表达。
用简化模型分析轮轨系横向动力响应
朱剑月,董光炎,李莉,
铁道工程学报 , 2002,
Abstract: ?根据轨道结构轮轨相互作用特点,建立了冲击荷载作用下轨道结构横向振动简化摸型。在一系列假定的基础上,利用matlab的simulink?语言编制轮轨动力作用程序,通过改变钢轨扣件横向刚度和道床横向刚度,观察其对轮轨系统横向振动持性及钢轨磨损的影响。结果表明:对曲线地段轨道结构横向刚度进行合理取值,能有效地降低轮轨相互作用以及延缓轮轨磨损。
工程橡胶元件弹性特征参数的确定方法
刘艳,张济民,,李秋彤
- , 2016, DOI: 10.11908/j.issn.0253-374x.2016.11.011
Abstract: 对橡胶材料进行大形变单轴拉伸、单轴压缩和平面拉伸试验,基于非线性弹性理论拟合得出超弹性模型参数,一方面通过数值计算完整定义材料的初始剪切模量、杨氏模量、体积压缩模量、表征压缩模量,另一方面通过仿真分析准确预测大形变范围的非线性特征以及弹性体压缩变形应力应变关系对试件尺寸和试验边界条件的依赖性.而后,基于线弹性理论进行小形变单轴拉伸和压缩试验,并计算线性模量.分析结果表明,线性理论仅适用于拉伸和剪切小形变弹性体,而对于发生大形变或以压缩为主的复杂形变弹性体而言,大形变试验结合非线性理论和仿真分析是获取有效弹性特征参数的最佳手段.
Determination of resilient coefficients of rubber material is essential to the design and optimization of elastomers in most engineering fields. Based on the nonlinear elasticity theory, a set of experiment including uniaxial tension, uniaxial compression and planar tension tests under large deformation was conducted and coefficients of a hyperelastic model were fitted. The testing data and corresponding simulation results can be used, on the one hand, to integrallty define the initial shear modulus, Young’s modulus, bulk modulus and apparent compressive modulus of present material, and on the other hand, to accurately predict the material nonlinearity and strong dependence of compressive modulus under different test conditions. Then a set of material mechanics experiment within small deformations was performed and the corresponding linear modulus were calculated. Finally, several conclusions about small and large material mechanics experiment as well as linear and nonlinear elastic theory were proposed through comparative analysis
使用挖泥船在哥伦比亚河沉降管道

天然气工业 , 1990,
Abstract: ?西北管道公司(nwp)拥有的两条φ406mm波特兰煤气支线,横穿哥伦比亚河,担负着向波特兰地区煤气输配公司运送煤气的任务.该管线最大操作压力为5.578mpa,已连续运行33年.由俄勒冈州波特兰市雷多国际公司(riedelinternational,inc)子公司西太平洋疏竣公司承担的清理疏挖工作,目的是向两条管道提供适当的覆盖层.这两条支线系统近来由于河底泥砂受水流冲刷,造成局部(几百英尺)管道暴露于水中.因此,存在着因行船抛锚或河道挖泥船作业而造成管道损坏的潜在危险.
我国水资源的刑事法律保护机制研究

人民黄河 , 2011,
Abstract: ?分析了我国刑法对水资源保护的现状和刑法保护的价值基础.刑法与行政手段和民事处罚手段相比,其起着一种导向性的作用.作为一种最严厉的保护手段,刑罚体现着社会伦理价值观念和价值取向.针对我国水资源的刑事立法提出了以下建议:增设相关罪名,构建严密的水资源刑事法律保护法网;加强法律制度的有效衔接,完善水资源刑事保护法律体系;改变重大环境污染事故罪的举证原则,实现刑法的公正性等.
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