临夏回族中指节纹的研究

根据Ｐｌｏｅｔｚ－Ｒａｄｍａｎｎ分类法，对甘肃省临夏州４３７名回族中学生的中指节纹进行了观察研究，结果表明，回族人的中指节纹以直线型（３９．４％）最常见，其次为弓型（２５．７４％），角型（１３．３９％）和钩型（１１．７６％）。并与国内的汉族资料做了比较分析。

龙门石窟唐代佛像颈部三道蚕节纹缘由探析

龙门石窟唐代造像数量多,保存也相对较好,这为研究唐代佛像造像的特点提供了丰富的资料。唐代佛像颈部有三道蚕节纹,不仅被称为佛身三十二相之一的瑞相,更是龙门石窟唐代造像的标志特征。但该特征未继承龙门石窟北魏佛像“瘦骨清像”的风格。唐代佛像颈部三道蚕节纹与佛身三十二相是否相关,该特征从何而来,学界对此探讨较少。依据汉译佛典中有关三十二相说的原型及内容的记载,对龙门石窟、云冈石窟的佛像特征进行梳理,与新疆、印度地区的佛像进行对比,得出龙门石窟唐代造像三道蚕节纹的特征并非源自佛身三十二相。龙门石窟唐代佛教三道蚕节纹在印度、新疆、云冈等地造像特征的影响下,又融入中原地区文化的特征所形成。

我国首次发现的暗纹节菱孢所致皮肤真菌病的毒理实验及病理分析

从患者皮损处皮屑及活检组织中分离出的暗纹节菱孢Arthriniumphaeospermum（Corda）Ellis菌株制成混悬菌液，用兔、豚鼠及小鼠（LACA）进行动物毒理实验。表皮直接涂抹法接种，四周后未见皮肤损害；划破表皮涂沫法及皮下注射法接种，两周后实验动物的皮肤都出现浸润性斑块、小给节、皮下脓肿及脱毛的症状，对照组动物正常。再用腹腔注射法接种，小鼠两周后死亡，病解所见，腹膜、肠系膜、腹壁及肝等处，均出现散在的灰白色小脓肿；心、肺、肝、脾及肾均有病变。豚鼠两周后仍存活，当即处死解剖所见与小鼠病解改变相同。对实验动物皮损、腹膜、肠系膜、胃及肝等处的小脓肿组织进行了病理检查，结果发现皮损及器官组织均有明显的病理浸润，由多种细胞构成的浸润性肉芽肿。在病理浸润内可见大小不等的球形、卵圆形、棱形及晶体形的棕色、红色孢子．其病理改变与患者皮损病理改变相一致，其不同点是实验动物有小脓肿，肉芽肿内可见多核巨噬细胞，而在病人皮损中很少见到。

Acoustic characteristics of the tiger frog,Hoplobatrachus rugulosus,during the breeding season

We recorded and described the calls and acoustic characteristics of the male tiger frog,Hoplobatrachus rugulosus,in an artificial pond during mating season.Spectral and temporal call parameters,along with call intensity were analyzed.Three harmonics were distinguishable from the spectrogram.Four patterns of dominant frequency were found in calls produced late at night,i.e,3 patterns in the first harmonic（located in 500 Hz section,700 Hz section,and 800 Hz section respectively） and 1 in the second harmonic（located in 1 800 Hz section）.Call duration,call duty cycle,call intensity,and pulse rate were highly variable among different patterns of dominant frequency.These call properties could provide valuable evidence for further ecological study of this species.

Effects of wheelset vibration on initiation and evolution of rail short-pitch corrugation

The initiation and evolution of short-pitch corrugation in Beijing metro line 4 was studied from the viewpoint of wheelset vibration.A three-dimensional elastic model was set up.Numerical simulations were undertaken with this model to analyze the corrugation by the wheelset vertical vibration and torsional vibration.Based on numerical results,the relation between rail corrugation and wheelset vibration,and the relation between the position of electromotor and wheelset vibration were indicated.It is found that avoiding the wheelset-rail resonance is one method of controlling the rail short-pitch corrugation and solving the vibration and noise problem in metro lines.

Finite element simulation of stress intensity factors in elastic-plastic crack growth

A finite element program developed elastic-plastic crack propagation simulation using Fortran language. At each propagation step, the adaptive mesh is automatically refined based on a posteriori h-type refinement using norm stress error estimator. A rosette of quarter-point elements is then constructed around the crack tip to facilitate the prediction of crack growth based on the maximum normal stress criterion and to calculate stress intensity factors under plane stress and plane strain conditions. Crack was modelled to propagate through the inter-element in the mesh. Some examples are presented to show the results of the implementation.

Equivalent elastic compliance tensor for rock mass with multiple persistent joint sets:Exact derivation via modified crack tensor

Discontinuities constitute an integral part of rock mass and inherently affect its anisotropic deformation behavior.This work focuses on the equivalent elastic deformation of rock mass with multiple persistent joint sets.A new method based on the space geometric and mechanical properties of the modified crack tensor is proposed,providing an analytical solution for the equivalent elastic compliance tensor of rock mass.A series of experiments validate the capability of the compliance tensor to accurately represent the deformation of rock mass with multiple persistent joint sets,based on conditions set by the basic hypothesis.The spatially varying rules of the equivalent elastic parameters of rock mass with a single joint set are analyzed to reveal the universal law of the stratified rock mass.

Experimental study on acoustic emission characteristics of jointed rock mass by double disc cutter

The characteristics of joints are crucial factors which influence the penetration efficiency of tunnel boring machine(TBM).Based on the theoretical study,numerical simulation and experimental research,many researchers have studied the interaction between TBM disc cutters and jointed rock mass.However,in most of these works,the effect of joint on rock fragmentation by double disc cutter has been scarcely investigated.Thus,the effects of joint orientation and joint space on rock fragmentation by double disc cutter are highlighted in this study.During the test,jointed concrete specimens are adopted to simulate jointed rock mass.Improved RYL-600rock shear rheological instrument was employed during the indentation process under disc cutters,and acoustic emission location system was used to analyze the rock damage and physical deterioration.The results show that there are four failure modes and three modes of crack initiation and propagation in jointed rock mass.It is concluded that the existing joint planes have obviously restrained the crack initiation and propagation during the rock fragmentation process.The results also indicate that samples are damaged most seriously when joint orientation equals60°,which is proved to be the optimum joint orientation in TBM penetration.

Evaluation of Energy Saving Operational Modes for Industrial Fracture Connected Processes on the Basis of Incubation Time Fracture Criterion

A problem for a central crack in a plate subjected to plane strain conditions is investigated. Mode I crack loading is created by a dynamic pressure pulse applied at a large distance from the crack. It was found that for a certain combination of amplitude and duration of the pulse applied, the energy transmitted to the sample has a strongly marked minimum, meaning that with the pulse amplitude or duration moving away from the optimal values, minimum energy required for initiation of crack growth increases rapidly. The results obtained indicate a possibility to optimise energy consumption of different industrial processes connected with fracture. Much could be gained in, for example, drilling or rock pounding where energy input accounts for the largest part of the process cost. Presumably further investigation of the effect observed can make it possible to predict optimal energy saving parameters, i.e. frequency and amplitude of impacts, for industrial devices, e.g. bores, grinding machines, and hence significantly reduce the process cost. The pre- diction can be given based on the parameters of the media fractured （material parameters, prevalent crack length and orientation, etc.）.

Crack initiation stress and strain of jointed rock containing multi-cracks under uniaxial compressive loading: A particle flow code approach

The ratio of crack initiation stress to the uniaxial compressive strength(SCI,B/SUC,B) and the ratio of axial strain at the crack initiation stress to the axial strain at the uniaxial compressive strength(B,UCB,CI,A,A/SSSS) were studied by performing numerical stress analysis on blocks having multi flaws at close spacing's under uniaxial loading using PFC3 D. The following findings are obtained: SCI,B/SUC,B has an average value of about 0.5 with a variability of ± 0.1. This range agrees quite well with the values obtained by former research. For joint inclination angle, β=90°,B,UCB,CI,A,A/SSSS is found to be around 0.48 irrespective of the value of joint continuity factor, k. No particular relation is found betweenB,UCB,CI,A,A/SSSS and β; however, the average B,UCB,CI,A,A/SSSS seems to slightly decrease with increasing k. The variability ofB,UCB,CI,A,A/SSSS is found to increase with k.Based on the cases studied in this work,B,UCB,CI,A,A/SSSS ranges between 0.3 and 0.5. This range is quite close to the range of 0.4to 0.6 obtained for SCI,B/SUC,B. The highest variability of ± 0.12 forB,UCB,CI,A,A/SSSS is obtained for k=0.8. For the remaining k values the variability ofB,UCB,CI,A,A/SSSS can be expressed within ± 0.05. This finding is very similar to the finding obtained for the variability of SCI,B/SUC,B.

Research and Development of ITER Bellows Assemblies

In ITER facilities, there are some special expansion joints connected with the openings of cryostat. Expect for the assemblies connected with NB openings, others are rectangular section with big dimensions and severe working conditions and they are important for ITER safe runing.

H_2S Stress Corrosion Tests of Welded Joint for X65 Pipeline Steel and Finite Element Numerical Analysis of Crack Tip

The microstructure of welded joint is surveyed and the mechanical properties of X65 pipeline steel are studied in this paper, which provides experimental basis of performance effect on stress corrosion. H 2S stress corrosion cracking (SCC) tests on the steel are carried out in the environment based on NACE TM- 01-77 solution. The threshold stress intensity factor and crack propagation velocity for base metal and HAZ are obtained. The susceptibility of welded joint for X65 pipeline steel to H 2S stress corrosion cracking is investigated. The programming package ANSYS of finite element model (FEM) is used to perform the three-dimensional elastic-plastic finite element analysis of WOL specimens. Stress field and concentration of hydrogen distribution property of the crack tip are obtained.

Research on downward crack closing of clay aquiclude in shallow coal seam safety mining

The water resisting property of aquiclude is the key factor of water conservation and safety mining, and the mining induced cracks in aquiclude is major factor of water resisting property. The aquiclude is composed by loess layer and red clay layer in Yushuwan Coal Mine, and the water reaction property of clay and loess of aquiclude was tested by soil mechanics method. The permeability coefficient of the loess is 0.856 m/d and the clay is 0.434 m/d. The dilatability coefficient of the loess is 16.1% and the clay is 14.6%. Through physical solid-liquid simulation with whole stress-stain similarity, the distribution of ＂downward crack zone＂ and ＂upward crack zone＂ was found to be the major factor of aquiclude stability. The downward crack closing length is about 30% of the downward crack length. The expanding of clay and loess with water are principal factors of downward crack closing. At last, the mechanical model of downward crack closing was constructed, and the criterion of crack closing was put forward at all. This work will provides the theoretical base for aquiclude stability research and safety mining in shallow seam.

中国人指型的观察从指远端相对长论指型

本文就19-25岁青年700人(男女各半)观察了指远端的相对长。中指最长,拇指最短。环、食指之间的相对长可分为三型:甲型,食指长于环指,占13.9外;乙型,环指长于盒指,占78.70Jo;丙型,食指与环指等长,占7.4呢。在男女两性间,甲型的出现率女(190l0)高于男(8.9务),乙型的出现率,男(85多)高于女(72.3多)。在左右手之间,各型的出现率无显著差别。小指远端亦可依其与环指远侧指间关节纹的相对长分为三型:短型占61.9形,中间型占17.3务。长型占20.8多。短型小指男性出现率(49外)低于女性(74.9多)。从测量食、环指远端距中指远端的距离,证实观察的结果与测量的结果是吻合的。食、环、小三指相对长在左右手的对称情况是:完全对称占58.3多,部分对称占22.7多,完全不对称占4.6多。部分不对称占14.4多。部分刘一称和部分不对称的出现率,在男女之间存在着显著的差别。

Modeling complex crack problems using the three-node triangular element fitted to numerical manifold method with continuous nodal stress

A three-node triangular element fitted to numerical manifold method with continuous nodal stress, called Trig_3-CNS(NMM)element, was recently proposed for linear elastic continuous problems and linear elastic simple crack problems. The Trig_3-CNS(NMM) element can be considered as a development of both the Trig_3-CNS element and the numerical manifold method(NMM).Inheriting all the advantages of Trig_3-CNS element, calculations using Trig_3-CNS(NMM) element can obtain higher accuracy than Trig_3 element without extra degrees of freedom(DOFs) and yield continuous nodal stress without stress smoothing. Inheriting all the advantages of NMM, Trig_3-CNS(NMM) element can conveniently treat crack problems without deploying conforming mathematical mesh. In this paper,complex problems such as a crucifix crack and a star-shaped crack with many branches are studied to exhibit the advantageous features of the Trig_3-CNS(NMM) element. Numerical results show that the Trig_3-CNS(NMM) element is prominent in modeling complex crack problems.

Triangular element partition method with consideration of crack tip

In fracture simulation,how to model the pre-existing cracks and simulate their propagation without remeshing is an important topic.The newly developed triangular element partition method(TEPM)provides an efficient approach to this problem.It firstly meshes the cracked body regardless of the geometry integrity of the interesting object with triangular elements.After the meshing procedure is completed,some elements are intersected by cracks.For the element intersected by a crack,the TEPM takes the element partition technique to incorporate the discontinuity into the numerical model without any interpolation enrichment.By this approach,the TEPM can simulate fracture without mesh modification.In the TEPM,all the cracked elements are treated as the usual partitioned elements in which the crack runs through.The virtual node pairs(the intersection points of crack faces and elements)at the opposite faces of the crack move independently.Their displacements are respectively determined by their neighbor real nodes(nodes formatted in the original mesh scheme)at the same side of the crack.However,among these cracked elements,the element containing a crack tip,referred to as the crack tip element thereafter,behaves differently from those cut through by the crack.Its influence on the singular field at the vicinity of the fracture tip becomes increasingly significant with the element size increasing.In the crack tip element,the virtual node pair at the crack tip move consistently before fracture occurs while the virtual node pair separate and each virtual node moves independently after the fracture propagates.Accordingly,the crack tip element is automatically transformed into the usual partitioned element.In the present paper,the crack tip element is introduced into the TEPM to account for the effect of the crack tip.Validation examples indicate that the present method is almost free from the element size effect.It can reach the same precision as the conventional finite element method under the same meshing scheme.But the TEPM is much more efficient and convenient than the conventional finite element method because the TEPM avoids the troubles that the conventional finite element method suffers,e.g.,the meshing problem of cracked body,modification of mesh scheme,etc.Though the extended finite element method can also avoid these troubles,it introduces extra degrees of freedom due to node interpolation enrichment.Due to the simplicity of the present TEPM,it is believed that its perspective should be highly inspiring.