新疆库鲁克塔格东缘新元古代大平梁铜多金属矿床地质特征及成因探讨

库鲁克塔格属于塔里木盆地东北缘出露的基底(李铨等,2002)。主要由一套太古代—中元古界花岗岩类变质岩,碳酸岩及碎屑岩组成。大平梁矿床位于库鲁克塔格东缘,产于大理岩与岩体接触交代矽卡岩中。是新发现的新元古代时期形成的矿床(830Ma,Caoetal.,2010),是新疆库鲁克塔格地块唯一在开采的铜多金属矿床,伴生铁、钼、金。该典型矿床的成因解剖对于库鲁克塔格成矿带成矿规律的探讨具有重要意义。

四川巴州平梁城城防设施调查简报

位于今四川省巴中市巴州区的平梁城始建于南宋淳祐十一年(1251),是宋蒙战争时期宋军在米仓山南麓修建的重要山城。南宋末年至清晚期,平梁城多次被重修利用,并成为巴州军民的避乱之所,巴州州治亦曾数度迁治城上。遗址内现存城墙、城门、炮台、墩台等大量宋代以来的城防设施,体现了多个历史时期的修筑痕迹,具有重要的研究价值。

谈西汉早期的“法钱”——“平梁四两”

1991年秋,兴和县文博人员在复查大同夭村故城遗址中,发现了西汉早期的"法钱"法码——"平梁四两"。同时出土的还有,战国时期赵国布币"榆半布"及秦汉时期的瓦当、简瓦、板瓦及灰陶罐等。"法钱"面为长方形,长3.4、宽2.8、厚0.7厘米,至覆顶面厚1厘米。背属覆斗形,覆顶面约长1.8、宽约1.4厘米。从左侧面凹处,明显看出纽残(图2)。

Analysis of plane strain bending of a strain hardening curved beam based on unified yield criterion

The analysis of plane strain elastic-plastic bending of a linear strain hardening curved beam with a narrow rectangular cross section subjected to couples at its end is conducted based on a unified yield criterion. The solutions for the mechanical properties of plane strain bending are derived, which are adapted for various kinds of non-strength differential materials and can be degenerated to those based on the Tresca, von Mises, and twin-shear yield criteria. The dependences of the two critical bending moments, the radii of the interfaces between the elastic and plastic regions and the radial displacements of the points at the symmetrical plane on different yield criteria and Poisson’s ratios are discussed. The results show that the influences of different yield criteria and Poisson’s ratio on the two critical bending moments, the radii of the interfaces between the elastic and plastic regions and the radial displacements of the points at the symmetrical plane of the curved beam are significant. Once the value of bis obtained by experiments, the yield criterion and the corresponding solution for the materials of interest are then determined.

这个社是如何抓好扶贫贷款收回工作的

农村金融部门,如何切实抓好扶贫贴息贷款收回工作?巴中县平梁乡信用社在实践中创造了经验。1987年以来.该社共向全乡70个农业生产合作社中的266个贫困农户发放扶贫贴息贷款89161元,到1991年11月末已收回64.63%,完成计划的258%,成为该县扶贫贴息贷款收回得最好的一个乡,他们在收贷工作中主要把住了以下几个关键环节。

宽桥混凝土路面无模板施工

介绍在宽桥混凝土路面施工中 ,利用两侧防撞护栏预留钢筋固定支架 ,安装轨道供宽幅整平梁整平 ,使桥面无纵向接缝和板差 。

跨河段给水管道精确安装施工技术研究

结合四川省营山县幸福水库应急补水工程中的跨河段管道安装工程实例,提出一种跨河段管道支撑结构支模体系,采用定型化挂架移动浇筑与振捣技术,结构设计新颖,模板制作加工简单,装拆模板便捷,避免了不安全因素,成本降低;采用的移动刮平梁和混凝土浇筑料斗,可实现不同高度要求的浇筑和刮平,节约施工时间。

Fabrication and Simulation of an Electromagnetic Microrelay

The fabrication and simulation of an electromagnetic microrelay are presented based on micro electromechanical systems (MEMS) technique.The microrelay dimensions of about 4mm×4mm×0 5mm are fabricated with the common technique of micromachining.Compared with the traditional relays,a planar coil is substituted for a solenoid coil to favor the MEMS fabrication.Moreover,a bi supporter cantilever beam with high sensitivity is fabricated to act as the movable electrode of the microrelay.Theoretical calculations and simulations are also carried out with respect to the electromagnetic force yielded by the exciting electromagnetic coil.The structure and parameters concerning the electromagnetic microrelay can be optimized using the results.

Effects of fundamental factors on coupled vibration of wind-rail vehicle-bridge system for long-span cable-stayed bridge

In a wind-vehicle-bridge(WVB) system,there are various interactions among wind,vehicle and bridge.The mechanism for coupling vibration of wind-vehicle-bridge systems is explored to demonstrate the effects of fundamental factors,such as mean wind,fluctuating wind,buffeting,rail irregularities,light rail vehicle vibration and bridge stiffness.A long cable-stayed bridge which carries light rail traffic is regarded as a numerical example.Firstly,a finite element model is built for the long cable-stayed bridge.The deck can generally be idealized as three-dimensional spine beam while cables are modeled as truss elements.Vehicles are modeled as mass-spring-damper systems.Rail irregularities and wind fluctuation are simulated in time domain by spectrum representation method.Then,aerodynamic loads on vehicle and bridge deck are measured by section model wind tunnel tests.Eight vertical and torsional flutter derivatives of bridge deck are identified by weighting ensemble least-square method.Finally,dynamic responses of the WVB system are analyzed in a series of cases.The results show that the accelerations of the vehicle are excited by the fluctuating wind and the track irregularity to a great extent.The transverse forces of wheel axles mainly depend on the track irregularity.The displacements of the bridge are predominantly determined by the mean wind and restricted by its stiffness.And the accelerations of the bridge are enlarged after adding the fluctuating wind.

Closed-form solution for shear lag effects of steel-concrete composite box beams considering shear deformation and slip

Based on the consideration of longitudinal warp caused by shear lag effects on concrete slabs and bottom plates of steel beams,shear deformation of steel beams and interface slip between steel beams and concrete slabs,the governing differential equations and boundary conditions of the steel-concrete composite box beams under lateral loading were derived using energy-variational method.The closed-form solutions for stress,deflection and slip of box beams under lateral loading were obtained,and the comparison of the analytical results and the experimental results for steel-concrete composite box beams under concentrated loading or uniform loading verifies the closed-form solution.The investigation of the parameters of load effects on composite box beams shows that:1) Slip stiffness has considerable impact on mid-span deflection and end slip when it is comparatively small;the mid-span deflection and end slip decrease significantly with the increase of slip stiffness,but when the slip stiffness reaches a certain value,its impact on mid-span deflection and end slip decreases to be negligible.2) The shear deformation has certain influence on mid-span deflection,and the larger the load is,the greater the influence is.3) The impact of shear deformation on end slip can be neglected.4) The strain of bottom plate of steel beam decreases with the increase of slip stiffness,while the shear lag effect becomes more significant.

A recursive formulation based on corotational frame for flexible planar beams with large displacement

A forward recursive formulation based on corotational frame is proposed for flexible planar beams with large displacement.The traditional recursive formulation has been successfully used for flexible mutibody dynamics to improve the computational efficiency based on floating frame,in which the assumption of small strain and deflection is adopted.The proposed recursive formulation could be used for large displacement problems based on the corotational frame.It means that the recursive scheme is used not only for adjacent bodies but also for adjacent beam elements.The nodal relative rotation coordinates of the planar beam are used to obtain equations with minimal generalized coordinates in present formulation.The proposed formulation is different from absolute nodal coordinate formulation and the geometrically exact beam formulation in which the absolute coordinates are used.The recursive scheme and minimal set of dynamic equations lead to a high computational efficiency in numerical integration.Numerical examples are carried out to demonstrate the accuracy and validity of this formulation.For all of the examples,the results of the present formulation are in good agreement with results obtained using commercial software and the published results.Moreover,it is shown that the present formulation is more efficient than the formulation in ANSYS based on GEBF.

The study of temperature effects on steel box girder for Taizhou Bridge

Using the temperature gradient which was proposed by continuously measuring flat steel box girder of Runyang Bridge, temperature effects of flat steel box girder were studied for Taizhou Bridge. With three temperature gradient models （JTG D60--2004 specification, BS5400 specification and the temperature gradient which was proposed in this paper）, the stress of control sections was calculated by finite element program ANSYS. The calculated result indicated that the temperature gradient that was put forward in JTG D60-2004 specification and BS5400 specification for calculating the stress of fiat steel box girder was not suitable to apply to fiat steel box girder. The temperature gradient on flat steel box girder which was proposed in this paper was reasonable.

General design of Sutong Bridge

The main span of Sutong Bridge is a double-pylon,double-plane cable-stayed bridge with steel box girder,which has the world's longest central span of 1 088 m within cable-stayed bridges.To overcome problems caused by severe meteorological conditions,perplexing hydrological conditions,deep buried bedrock and higher navigation level,many new technics and methods were created.Keys including structural system,steel box girder,stayed cable,tower,pier,tower foundation,collision avoidance system,wind-resistance,seismic-resistance,structural nonlinear response and structural static stability were presented individually in this paper.

Failure of Semi-infinite Beams of Variable Thickness and Curvature on Elastic Foundation under Contact Loading

In early winter it is usual, in cold regions, that ice features approach offshore structures, like offshore platforms, impacting them, in a slow process of constant deformation build up. Interaction follows, in many cases, up to the point where ice-failure caused by bending fracture takes place. This supposes very large contact forces that the structure has to resist. Therefore, quantification of these efforts is of vital importance to the structural design of platforms. In several designs, these platforms are constructed with inclined walls so as to cause ice to fail in a flex-compression mode. In such a case the ice feature is analyzed as a beam constituted of a linear elastic material in brittle state with constant ice thickness. The simplification renders the problem solvable in a close form. However, this hypothesis goes against field observations. Marine currents action, wind and the sequence of contacts among features lead to thickness variations. Here this factor is addressed in the construction of a model, for harmonic forms of variation of thickness profile, and the accompanying curvature variations, whose solution determines field variables used to address the failure question. Due to the deformation dependency of the loading, a numerical scheme for the two-point boundary value problem in the semi-infinite space is developed. Failure pressures are computed based on a Rankine locus of failure. Variations of the order of 20% in the failure loads, as compared to the uniform beam model, are observed.

Comparison on construction of strut-and-tie models for reinforced concrete deep beams

With consideration of the differences between concrete and steel,three solutions using genetic evolutionary structural optimization algorithm were presented to automatically develop optimal strut-and-tie model for deep beams.In the finite element analysis of the first method,the concrete and steel rebar are modeled by a plane element and a bar element,respectively.In the second method,the concrete and steel are assigned to two different plane elements,whereas in the third method only one kind of plane element is used with no consideration of the differences of the two materials.A simply supported beam under two point loads was presented as an example to verify the validity of the three proposed methods.The results indicates that all the three methods can generate optimal strut-and-tie models and the third algorithm has powerful capability in searching more optimal results with less computational effort.The effectiveness of the proposed algorithm III has also been demonstrated by other two examples.

Prediction Model for Fatigue Stiffness Decay of Concrete Beam Based on Neural Network

With the method of neural network, the processes of fatigue stiffness decreasing and deflection increasing of reinforced concrete beams under cyclic loading were simulated. The simulating system was built with the given experimental data. The prediction model of neural network structure and the corresponding parameters were obtained. The precision and results were satisfied and could be used to investigate the fatigue properties of reinforced concrete beams in complex environment and under repeating loads.

《宋书》《氐胡传》与《萧思话传》记时辨误

近读《宋书》,发现《氐胡传》与《萧思话传》在记载司马飞龙寇蜀、杨难当据汉中、萧思话平梁州等事件的时间有误,又中华书局校点本在二传中有不恰当的改字。今并辨析于下。《宋书·氐胡传》载:"先是,四方流民有许穆之、郝恢之二人投(杨)难当,并改姓为司马。穆之自云名飞龙,恢之自云名康之……(元嘉)十年,难当以益州刺史刘道济失蜀土人情,以兵力资飞龙,使入蜀为寇,道济击斩之。"而《宋书·刘粹传附道济传》则载:"有司马飞龙者……

《元和郡县志》盐州沿革辨误

《元和郡县志》卷四盐州条下有:汉武帝元朔二年置五原郡,地有原五所,故号五原。至晋,地没赫连勃勃,后魏平之,改为西安卅,以其地北有盐池,又改为盐州。隋大业三年为盐川郡。贞观二年讨平梁师都,置盐州。天宝元年改为五原郡,乾元元年复为盐州。”据此,唐之盐州应即汉武帝元朔二年所置五原郡,但事实并非如此。

Temperature gradient and its effect on flat steel box girder of long-span suspension bridge

The temperature field variation law and distribution characteristics of an orthotropic flat steel box girder under sunny conditions were analyzed through a field temperature test on the steel box girder of the operational Runyang Yangtze River Bridge(the suspension bridge part).Function optimization fitting and error analysis of the test data were conducted.A temperature gradient distribution curve applicable to a hexagonal flat steel box girder was proposed.Based on the measurement results,the temperature effect of an orthotropic flat steel box girder was analyzed using finite element method and the effects of different temperature gradient modes on the mechanical characteristics and stress distribution of the steel box girder were compared.Under sunny conditions,heat conduction in the flat steel box girder structure shows distinct "box-room effect" characteristics,and the actual temperature gradient distribution is inconsistent with the one suggested by the existing standards.The thermal stress of a steel box girder calculated from the measured temperature gradient mode exceeds that calculated from the standard,and the intensity approximates that under the action of designed vehicle loads.The temperature-induced stress is distributed centrally near the manufacturing welds of the orthotropic steel box girder,which should be considered in design,construction and research.Results from this study could supplement the existing bridge and culvert design standards.