Research on the Cause and Influential Factors of Tunnel Lining Cracking of Side Wall in Seasonally-frozen RegionsEI北大核心

Research purposes: In recent years, tunnel diseases like lining cracking and water leaking during spring thawing period, caused by frost heaving of surrounding rock, have occasionally occurred in high-latitude seasonally-frozen regions of northwest China and northeast China, which has seriously affected the tunnel structure and operation safety. Taking several railway tunnels in northwest China as an example, this paper investigates the cause and main influencing factors of longitudinal cracking of side wall in winter in seasonal frozen soil area by means of field test, laboratory experiment and numerical simulation. Research conclusions:(1) When the water content of surrounding rock of tunnel built in strongly-weathered sandstone is 12.3% and the frozen depth of surrounding rock is up to 60 cm, the maximum tensile stress of side walls is 2.28 MPa, which is larger than the ultimate tensile strength of C30 concrete, then the horizontal lining cracking will appear on side walls under the effect of continuous negative temperature in winter. If the lining bears part of the surrounding rock load, the longitudinal cracking degree of the side wall will increase. (2) Under the effect of frost heaving loads, the cracking of tunnel lining has its own characteristics of symmetry, seasonality and accumulation, etc. The cracks appear in winter and distribute in the middle of side walls. As the temperature is rising, the crack begins to shrink. (3) The frozen circle thickness and water content of surrounding rock should be used as main indicators during the process of calculation of frost heaving loads of surrounding rock in seasonally-frozen regions. (4) The research results can be used for reference in tunnel design, operation and maintenance in seasonal frozen soil area. © 2018, Editorial Department of Journal of Railway Engineering Society. All right reserved.     

Analysis of damping performance of isolated rubber floating slabEI北大核心

Research purposes: The basic component of the track structure with isolated rubber floating slab is the concrete slab track born by the elastic element. The research was done on the mechanical properties of the floating slab, the analysis was made for the natural frequencies, mechanical response under dynamic load and damping performance, and the discussion was made on the reasonable thickness of the ballastless track to provide the reference to the track design. Research conclusions: The research results show that the natural frequency of the track system decreases with the increase of the thickness of the ballastless track, and the rate of change decreases with increase of the track thickness. The acceleration insertion loss of the track basis increases with the increase of the thickness of the ballastless track, and the rate of change decreases with increase of the track thickness. When the thickness of the ballastless track reaches at 0.4 m, the corresponding dynamic performance, the damping performance effect and the concrete amount of track bed are rather economical. From the present theoretical analysis and online testing, it can be seen the damping performance effect of the isolated rubber floating slab system is obvious, and its construction and maintenance programs are systematic.     

DISCREPANCY OF COCAINE EFFECT ON CONDUCTION AND REPOLARIZATION

ＤＩＳＣＲＥＰＡＮＣＹＯＦＣＯＣＡＩＮＥＥＦＦＥＣＴＯＮＣＯＮＤＵＣＴＩＯＮＡＮＤＲＥＰＯＬＡＲＩＺＡＴＩＯＮＬｉｕＤｏｎｇ；ＲｏｂｅｒｔＪ．Ｈａｒｉｍａｎ，ＨｅｎｒｙＳ．Ｌｏｅｂ，ＰａｔｒｉｃｋＪ．Ｓｃａｎｌｏｎ，ＪｅｒｒｙＬ．Ｂａｕｍａｎ，Ｈｉｎ...     

EXPRESSION OF PRE S ROTEIN OF HBV AS A ALKALINE PHOSPHATASE FUSION PROTEINS IN NIH 3T3 CELLS

ＥＸＰＲＥＳＳＩＯＮＯＦＰＲＥＳＲＯＴＥＩＮＯＦＨＢＶＡＳＡＡＬＫＡＬＩＮＥＰＨＯＳＰＨＡＴＡＳＥＦＵＳＩＯＮＰＲＯＴＥＩＮＳＩＮＮＩＨ３Ｔ３ＣＥＬＬＳＸｉａｏＳｈｅｎｇｘｉａｎｇ；Ｔ．Ｓ．Ｂ．Ｙｅｎ（ＬａｂｏｒａｔｏｒｙｏｆＭｏｌｅｃｕｌａｒＰａｔ...     

OPIOIDS MODULATE NMDA－EVOKED RESPONSES OF NEURONS IN THE SUPERFICIAL AND THE DEEPER DORSAL HORN OF THE MEDULLA

ＯＰＩＯＩＤＳＭＯＤＵＬＡＴＥＮＭＤＡ－ＥＶＯＫＥＤＲＥＳＰＯＮＳＥＳＯＦＮＥＵＲＯＮＳＩＮＴＨＥＳＵＰＥＲＦＩＣＩＡＬＡＮＤＴＨＥＤＥＥＰＥＲＤＯＲＳＡＬＨＯＲＮＯＦＴＨＥＭＥＤＵＬＬＡＫ．Ｍ．Ｚｈａｎｇ；ＷａｎｇＸｉａｏｍｉｎ；Ａ．Ｍ．Ｐｅｔｅｒ...     

胆石中游离和结合胆汁酸定量分析研究(薄层扫描色谱法)

在付立叶变换红外光谱(FT-IR)定性分类胆石的基础上,用薄层扫描色谱法进行胆石中游离和结合胆汁酸的定量分析研究。60例胆石经FT-IR 分为7种类型:胆固醇结石,胆固醇混合石、胆色素混合石、色素新型石、类色素型石、黑石磷酸盐型和黑石蛋白型。本文将从不同类型胆石游离和结合胆汁酸含量的差异,探讨胆汁酸在胆石成因中的作用.     

微型点焊镀镍钢板和镍板时电极失效机制研究

本文主要研究了微型点焊镀镍镀镍钢板和镍板时电极失效的机制。结果表明：微型点焊镀镍钢板和镍板时电极失效的机理是电极和镀镍板之间局部焊接的断裂发生在电极头部而导致的电极磨损和电极头部的塑性变形。阴极电极的失效速度高于阳极电极的失效速度,其原因是阳极电极的磨损主要发生在电极头部表面的边缘,而阴极电极磨损主要发生在电极头部的大部分表面,并且阳极的塑性变形小于阴极的塑性变形。     

土地开发利用和社会经济发展对家庭汽车拥有量的影响——沙特阿拉伯利雅得市和澳大利亚墨尔本市的比较(英文)

汽车保有量取决于城市的土地开发模式。在一定时期内,一个地区的就业、住房、休闲、教育和购物条件以及家庭成员的年龄、性别、收入和家庭规模都会影响到人们对出行目的地和出行方式的选择,而家庭住房位置的影响则是长期的。应用沙特阿拉伯利雅得和澳大利亚墨尔本两座城市数据,分析了城市总体用地水平和人均水平、家庭人口及其距离工作地点的路程等对家庭汽车拥有量的影响,建立了家庭汽车拥有量多项式逻辑模型。模型表明,城市扩张是影响家庭汽车拥有量的主要因素,利雅得市家庭汽车拥有量在2辆以上,而墨尔本市不少于1辆。     

MUTUAL INFORMATION BASED 3D NON-RIGID REGISTRATION OF CT/MR ABDOMEN IMAGES

Introduction　　 Automating medical image registration is be-coming an increasingly important goal. It formsthe basis of image processing techniques to com-bine information from the different modalities,which are now frequently acquired for many pa-tients. Such combined representations of patientimages have been shown to assistin the interpreta-tion of the complementary information provided bythe modalities[1,2 ] .　　 A variety of imaging modalities gives insightto different parameters and in…     

MODULATION OF A δ－AND C－FIBER EVOKED RESPONSES OF NOCICEPTIVE NEURONS IN THE SUPERFICIAL AND THE DEEPER DORSAL HORN OF THE ME

ＭＯＤＵＬＡＴＩＯＮＯＦＡδ－ＡＮＤＣ－ＦＩＢＥＲＥＶＯＫＥＤＲＥＳＰＯＮＳＥＳＯＦＮＯＣＩＣＥＰＴＩＶＥＮＥＵＲＯＮＳＩＮＴＨＥＳＵＰＥＲＦＩＣＩＡＬＡＮＤＴＨＥＤＥＥＰＥＲＤＯＲＳＡＬＨＯＲＮＯＦＴＨＥ　ＭＥＤＵＬＬＡ：ＲＯＬＥＯＦＯＰＩＯＩＤＲ...