西藏冲尼中二叠世岛弧玄武岩的发现及意义

最近在西藏直孔地区冲尼村附近识别出一套二叠纪岛弧玄武岩。本文报道了其岩相学、全岩地球化学及锆石U-Pb年代学数据,探讨了其岩石成因和构造背景。锆石U-Pb年代学和全岩地球化学分析显示,玄武岩浆结晶年龄为270.8±2.1 Ma,时代属中二叠世;全岩地球化学分析表明:冲尼玄武岩为钙碱性系列,轻稀土元素(LREE)富集,重稀土元素(HREE)相对亏损,无Eu异常,微量元素蛛网图显示,冲尼玄武岩亏损高场强元素(HFSE),富集大离子亲石元素(LILE)。综合区域地质调查研究成果,中二叠世冲尼岛弧玄武岩形成于直孔-松多古特提斯洋向北俯冲消减的构造背景下,由俯冲板片之上经流体交代的地幔楔部分熔融形成。

Effect of electropulsing on dislocation mobility of titanium sheet

To investigate the effect of the electropulsing on dislocation mobility,specimens cut from the cold-rolled titanium sheet were treated by high density electropulsing with the maximum current density of 7.22,7.64,7.96 kA/mm 2 ,pulse period 110μs.The internal friction and elastic modulus were measured by a dynamic mechanical analyzer（DMA）.When strain amplitude lowers a certain critical one,the damping of the electropulsed titanium sheet is lower than that of the cold-rolled one.When the strain amplitude exceeds the critical one,the damping of the electropulsed titanium sheet is extraordinarily higher than that of the cold-rolled or conventional annealed one.Furthermore,it is found that the damping peak of the electropulsed titanium sheet shifts to lower temperature compared with the conventional annealed one.It is demonstrated that the electropulsing treatment can decrease dislocation tangles and enhance dislocation mobility.

MULTI-GRANULE IMPACT MODEL OF NOPD AND ITS NUMERICAL SIMULATIONS

Aiming at the impaction among granules of non obstructive particle damping(NOPD), the vibration absorption model for vertical impact of granules is established by adopting Hertz contact theory. The numerical simulation of the granules movement process is proceeded, and the vibration response of a free free uniform beam is obtained for the case when all granules act on it. Through this method, the effect on vibration absorption of impaction is investigated. The simulational data show that multi gra nule vertical impaction is not sensitive to the movement clearance. The vibration absorption is also very well when the clearance changes within a large range. Therefore, the phenomenon that the vibration magnitude may increase if the clearance in a single impact body is improperly selected will not happen. The effect of vibration suppression in the range of middle and high frequencies(2 500~6 000 Hz) is better than that in the range of low frequency(<2 500 Hz). It indicates that the effect on vibration absorption of multi granule can well restrain the vibration of middle and high frequencies.

Effect of Inertial Shock on RF MEMS Capacitive Switches Property in Low Vacuum

The influence of outside inertial shock combined with RF signal voltages on the properties of a shunt capacitive MEMS switch encapsulated in a low vacuum environment is analyzed considering the damping of the air around the MEMS switch membrane. An analytical expression that approximately computes the displacement induced by outside shock is obtained. According to the expression, the minimum required mechanical stiffness constant of an MEMS switch beam in some maximum tolerated insertion loss condition and some external inertial shock environment or the insertion loss induced by external inertial shock can also be obtained. The influence is also illustrated with an RF MEMS capacitive switch example,which shows that outside environment factors have to be taken into account when designing RF MEMS capacitive switches working in low vacuum. While encapsulating RF MEMS switches in low vacuum diminishes the air damping and improves the switch speed and operation voltage,the performances of a switch is incident to being influenced by outside environment. This study is very useful for the optimized design of RF MEMS capacitive switches working in low vacuum.

Theoretical analysis and experimental investigation of a high-performance viscoelastic material shock absorber

To improve the performance of traditional mechanical shock absorber, a new type of high molecular polymer is formulated and applied to overloaded vehicle shock absorber. According to the operating principle of high-performance viscoelastic material shock absorber, the geometrical structure of shock absorber is designed and machined. Then its theoretical model is derived by using analytical method, and the impact test is carried out on high-performance viscoelastic material shock absorber. The results show that experimental and theoretical damping force curves have good agreement, which validates the credibility of theoretical model. The investigation provides a potential way to enhance damping performance and increase vehicle load.

Reduce the noise of punch press with the equivalent damping

To reduce the noise of the punch press during the punching process, the polyurethane elastomer is used as the damping material. The experiments of reducing noise were made by means of adding the polyurethane elastomer at different positions on the 100 kN and 1 000 kN punch presses. The better effect of reducing noise was obtained. After researching and analyzing a large number of test data, the ″equivalent damping hypothesis″ is put forward. The hypothesis makes the experiment of reducing noise simpler and also more economical. It is estimated that there is a vast application in the research area of vibration control and noise reduction.

Research on the dynamic performance of ship isolator system that use magnetorheological dampers

Isolator systems on ships should ideally be able to simultaneously reduce low frequency vibration response and high frequency shock response. Conventional isolator systems are unable to do so To solve the problem, a new style isolator system was created. This isolator system consists of a steel coil spring component and a magnetorheological （MR） damper component working in parallel. Experiments on this isolator system were carried out, including tests of vibration reduction and shock resistance. The vibration load frequencies were set from 1-15 Hz, and force amplitudes from 2.94-11.76kN. The maximum shock input acceleration was 20 g, and impulse width was lores. Both the vibration and shock loads were applied using MTS Systems Corporation＇s hydraulic actuators. The experimental results indicated that the isolator system performs well on system vibration response, with resonance humps of the vibration response obviously reduced after using the MR damper. For the shock experiment, the attenuation of shock response was much faster with increased MR damping. The MR damper＇s effect on shock moments was very different from its performance in vibration mode. The correlation between MR force and control current was not as evident as it was during vibration loads.

Statistical Constitutive Equation of Aramid Fiber Bundles

Tensile impact tests of aramid (Twaron) fiber bundles were carried out under high strain rates with a wide range of 0. 01/s -1 000/s by using MTS and bar-bar tensile impact apparatus. Based on the statistical constitutive model of fiber bundles, statistical constitutive equations of aramid fiber bundles are derived from statistical analysis of test data at different strain rates. Comparison between the theoretical predictions and experimental data indicates statistical constitutive equations fit well with the experimental data, and statistical constitutive equations of fiber bundles at different strain rates are valid.

Religion Conflicts in Indonesia Problems and Solutions

Religious perspectives which place religion as a source of conflict have initiated various attempts to reinterpret and accordingly find some common ground at a certain level which hopefully may reduce conflicts among religious communities due to the existence of mutual tolerance. At the exoteric level, religions are different, but at the esoteric level, religions are not similar. All religions are viewed as equally valid paths toward God. However, in many ways, the reality shows that the tension among religious communities is closely related to the factors that are beyond the scope of religion. It is important for all religious believers to keep the peace among them. As far as the record of religious conflicts in Indonesia is concerned, it shows three major patterns： conflicts among adherents of different religions, conflicts between one religion with a group accused as heretical, and internal conflicts of the same people of faith with those who have different understanding of the religion. In any point of views, however, such conditions would be so detrimental to the human race in general, and society and the state of Indonesia in particular. This paper examines intensively about the issues and attempts to uncover the nature of the root-causes underlying them.

Evaluation of a PV Powered EV Charging Station and Its Buffer Battery

This research analyses the operation of a solar PV powered electric vehicle charging station with energy storage, that has been developed and demonstrated at the University of California--Davis, West Village, the largest planned zero-energy consumption community in the U.S. The intelligent energy management approach introduces solar PV electrical energy forecasting and EV （electric vehicle） charging demand projection to optimize the SOC （state of charge） of the buffer battery. The charging station has been operated continuously and routinely used by several EV users for a year. The actual operation shows that, a workplace charging station equipped with a buffer battery and with intelligent energy management can lower and reduce the station＇s peak power demand, and reduce the energy exchange with the utility grid by a factor of 2. The battery recharging power demand was shifted away from the on-peak time periods to the off-peak time periods, which will benefit the charging station owner from less energy use during peak periods when time-of-use rates are higher. The standard cell voltage deviation of the 220 cells was calculated to analyse the battery cell consistency during the resting, charging and discharging periods. The analysis shows that, the 220 50Ah cells show excellent voltage consistency with voltage deviation of less than 0.005 V within the battery SOC of 20%-80%. The voltage deviation doubles when the battery SOC reaches 90%. The comparison of cell voltage deviation at the beginning and after one year operation indicates that, the battery shows perfect cell voltage consistency and there is no obvious consistency deterioration during the battery resting, charging and discharging periods.

The Development of Wildlife Community Conservancies in Kenya: A Preliminary Review

The significance of biodiversity conservation has transformed from a concern for conservation of endangered species and landscapes into an increasingly diverse yet comprehensive set of conservation, social and economic development goals. Community conservancy, a powerful extension of the PA system, has great potential to support biodiversity conservation, poverty eradication and conflict mitigation. Based on its policy environment and development characteristics, Kenya has implemented community conservation practices, and established over 160 conservancies across the country in the past decades. This paper reviews the development and experiences of community conservancies, discusses how they have been implemented in Kenya, and looks at the management paradigm, efficacy and challenges to help better understand the community conservancy approach. The development trajectory and lessons these conservancies have to offer can contribute to the sustainable utilization of natural resources and the enhancement of community wellbeing in Kenya and other countries alike.

Some Theories and Concepts of Intergroup and Conflict Relations in the Western Niger Delta of Nigeria

Intergroup conflicts occupy a special place in the interaction of social groups and of necessity form the basic building blocks for the integration of previously fragmented groups. The Western Niger delta obviously has since been a theatre of socio-political conflicts. Viewed from the contemporary clime, there is a lacuna in the formulation of theories and concepts in understanding and explaining the nature and pattern of intergroup relations in the region from the pre-colonial period. This work therefore attempts an exploratory analysis of some theories and concepts of intergroup relations in the Western Niger Delta of Nigeria using the historical approach with the use of secondary source materials. The paper concludes that the relation among the diverse ethnic groups in Nigeria, especially the Western Niger Delta, may not have been as intense, or as hostile as it has become since the attainment of independence in 1960. This paper no doubt is essential for the understanding and tackling of the problem of intergroup relations and conflict in the region in particular and Nigeria at large.

OWC air chamber performance prediction under impulse turbine damping effects

Oscillating water columns(OWCs)are most widely used in coastal wave energy conversion.The air duct opens into the atmosphere through the air turbine,which is the power take-off device,and this results in a pressure drop across the air chamber.However,because of the complex configure of the impulse turbine and its high rotation speed,it is difficult to install it in the experimental simulator and numerical model.Therefore,the turbine damping effects on the operation of the OWC air chamber are induced to predict its performance more accurately.Orifice plates are used as a substitute for the impulse turbine as it generates a similar pressure drop and power output;the experimental and numerical pressure drops and output powers are compared.A 3D numerical wave tank based on the two-phase VOF model is established using the commercial CFD code Fluent,which can predict air flow and pressure variations in the chamber and duct.Water surface elevations,air flow velocity and pressure variation inside the chamber with the orifice plate are studied numerically,and validated by the corresponding experimental data.The air chamber of the Yongsoo OWC pilot plant is used as the engineering project case.The operating performance of the air chamber installed with a 0.428D orifice plate as the substitute for the designed impulse turbine is computed and analyzed.It is found that the turbine damping effects will cause around 30%reduction in the peak values of the pneumatic energy output of the OWC air chamber in the resonant wave domain.

Almost periodic solution of Nicholson＇s blowflies model with linear harvesting term and impulsive effects

This paper is concerned with impulsive Nicholson＇s blowflies model with linear harvesting term. By using contraction mapping fixed point theorem, we obtain sufficient conditions for the existence of unique almost periodic positive solution. Moreover, we investigate exponential convergence of the almost periodic positive solution by Lyapunov functional.