A General Way for Determining Hawking Effect in Spherically Symmetric or Plane-symmetric Non-static Space-Times

A new general way for researching the Hawking effect in the spheri-cally symmetric or the plane-symmetric non-static space-times is proposed.The theoreticalfoundation of this way is laid.The Klein-Gordon equation must be reduced to the stand-ard form of wave equation near an event horizon when a generalized tortoise coordinateis adopted.Then,both the Hawking radiation temperature and the equation determining thelocation of the event horizon are obtained automatically.When the radiation is weak,thefirst approximation of our result is the same as the approximate result obtained with theradiation back-reaction method.

Non-state Political Theoretical Paradigm of African Union Citizenship

The charter that created the African Union came into effect in 2002. It is now 12 years in place but most Africans would not be sure whether they know the rationale and ultimate role of the AU in promoting good governance, peace, security and progress on the continent. Annual summits take place in Addis Ababa, and several resolutions are taken, but it is though the respective heads of states just return to their colonially engineered states to resume business as usual. As a result, poverty, conflicts （both internal and regional）, bad governance continue to plague the majority of the African countries with a few exceptions. Of late emerging economies such as China and India deal with Africa as if it were a one country--this could be the time for Africans to begin envisioning a new continental political architecture, with an African citizenship. The provisions of the African Union Charter are enshrined in the Constitutive Act, are summaries in Articles 3 and 4, that deal with objectives and principles. The objectives are （Desta, 2013, pp. 160-161）： （1） Achieve greater unity and solidarity between the African countries and peoples of Africa; （2） Defend the sovereignty, territorial integrity and independence of its member states; （3） Accelerate the political and social-economic integration of the continent; （4） Promote and defend African common positions on issues of interest to the continent and its peoples; （5） Encourage intemational cooperation, taking due account of the Charter of the United Nations and the Universal Declaration of Human Rights; （6） Promote, peace, security and stability of the continent; （7） Promote democratic principles and institutions, popular participation and good governance; （8） Promote and protect human and people＇s rights in accordance with the African Charter on Human and Peoples＇ Rights and other relevant human rights instruments; （9） Establish the necessary conditions which enable the continent to play its rightful role in the global economy and in international negotiations; （10） Promote sustainable development at the economic. Social and cultural levels as well as the integration of African economies; （11） Promote co-operation in all fields of human activity to raise the living standards of African peoples; （12） Coordinate and harmonize the policies between the existing and future Regional Economic Communities for the gradual attainment of the objectives of the Union; （13） Advance the development of the continent by promoting research in all fields, in particular in science and technology; （14） Work with relevant international partners in the eradication of preventable diseases and the promotion of good health on the continent. The principles of the AU Constitutive Act are （Ibid. 162-163）： （1） Sovereign equality and interdependence among Member Sates of the Union; （2） Respect for borders existing on achievement of independence; （3） Participation of the African peoples in the activities of the Union; （4） Establishment of a common defense policy for the African Continent; （5） Peaceful resolution of conflicts among Member States of the Union through such appropriate means as may be decided upon by the Assembly; （6） Prohibition of the use of force or threat to use force among Member States of the Union; （7） Non-interference by any Member State in the internal affairs of another; （8） The right of the Union to intervene in aMember State pursuant to a decision of the Assembly in respect of grave circumstances, namely： war crimes, genocide and crimes against humanity; （9） Peaceful co-existence of Member States and their right to live in peace and security; （10） The right of Member States to request intervention from the Union in order to restore peace and security; （11） Promotion of self-reliance within the framework of the Union; （12） Promotion of gender equality; m. Respect for democratic principles, human rights, rule of law and good governance; （13） Promotion of social justice to ensure balanced economic development; （14） Respect for the sanctity of human life, condemnation and rejection of impunity and political assassination, acts of terrorism and subversive activities; （15） Condemnation and rejection of unconstitutional changes of governments. While there is mention of participation of African peoples in the activities of the Union as principle （c） and objective （g）, there is no explicit mention of civil society organizations （media, faith-based organizations, and NGOs） as principle actors in implementing the objectives of the Union. I want to argue that the failure of the respective African states to eradicate poverty, end armed conflicts, and address governance issues is caused by lack of a common regional integration model that takes an African Union citizenship seriously, but at the same time respecting the role of civil society and faith-based organizations, that predate the state in Africa. It is evident that Afi＇ican Unity （AU） and sub-regional integration groups such as East African Community （EAC）, Southern African Development Community （SADC）, Economic Community Of West African States （ECOWAS）, as well the New Partnership for Africa＇s Development （NEPAD）, are designed and operationalized from a statist political philosophical framework. Moreover, since the African states are largely contested as a colonial creation, the AU cannot successfully implement the institution of an African citizenship without acknowledging the role of and giving space to non-state actors in AU and other regional integration models and initiatives. This paradigm shift will require rethinking the relationship between the state and non-state actors in Africa.

Delivering reproductive health services through non-state providers in Pakistan:understanding the value for money of different approaches

Background:Delivering Reproductive Health Results(DRHR)programme used social franchising(SF)and social marketing(SM)approaches to increase the supply of high quality family planning services in underserved areas of Pakistan.We assessed the costs,cost-efficiency and cost-effectiveness of DRHR to understand the value for money of these approaches.Methods:Financial and economic programme costs were calculated.Costs to individual users were captured in a pre-post survey.The cost per couple years of protection(CYP)and cost per new user were estimated as indicators of cost efficiency.For the cost-effectiveness analysis we estimated the cost per clinical outcome averted and the cost per disability-adjusted life year(DALY)averted.Results:Approximately£20 million were spent through the DRHR programme between July 2012 and September 2015 on commodities and services representing nearly four million CYPs.Based on programme data,the cumulative cost-efficiency of the entire DRHR programme was£4.8 per CYP.DRHR activities would avert one DALY at the cost of£20.Financial access indicators generally improved in programme areas,but the magnitude of progress varies across indicators.Conclusions:The SF and SM approaches adopted in DRHR appear to be cost effective relative to comparable reproductive health programmes.This paper adds to the limited evidence on the cost-effectiveness of different models of reproductive health care provision in low-and middle-income settings.Further studies are needed to nuance the understanding of the determinants of impact and value for money of SF and SM.

非牛顿流体在叶片式静态混合器中的传热强化特性

非牛顿流体在化学、食品和材料等领域具有关键作用,但高表观黏度使其通常具有低传热特性。叶片式静态混合器作为一种高效的传热强化设备,在化工过程强化中具有鲜明的技术特色。本文针对非牛顿流体在Kenics静态混合器(KSM)和Lightnin静态混合器(LSM)内的流动和传热特性进行了比较研究。重点分析了体积流量、元件长径比及流体浓度等参数对羧甲基纤维素(CMC)幂律流体的流动及传热影响。结果表明,在相同工况下,随着CMC溶液的体积流量增大,管道内的换热系数和压降均增大。静态混合元件的插入使得换热系数和压降显著提高且Lightnin元件产生的影响更明显。元件长径比和CMC溶液浓度影响流体在管道内的流动和换热。随着长径比的减小,传热性能得到提高,但其增大的阻力系数影响占据主导地位,综合换热性能系数(PEC)降低。溶液浓度的增大使得管道换热能力逐步削弱,并对管道内压降的提升有显著影响,综合换热性能降低。总结得出,在体积流量为4.5×10^(-4)m^(3)/s,质量分数为0.374%、长径比为3.0时,KSM的PEC最大为2.114。

基于静态凝聚法的蜂窝芯轴向变胞元非均匀排布优化

为了有效改善蜂窝结构的强度与刚度,提出利用静态凝聚法实现变胞元的几何参数和非均匀排布同时优化的方法。根据卡氏定理,推导胞元的等效弹性模量和泊松比;沿轴向均匀划分蜂窝芯为若干列子结构,利用有限元法得到子结构的刚度矩阵;采用静态凝聚法建立超单元刚度矩阵,依据超单元节点编号装配获得蜂窝芯的整体刚度矩阵;计算蜂窝芯在剪切载荷作用下的结构变形,并与ANSYS结果比较分析。以子结构的个数以及胞元的夹角、夹板宽与斜壁长之比为设计变量,胞元的等效弹性模量最大和蜂窝芯的变形最小为设计目标,利用改进的粒子群算法进行优化并研究蜂窝芯优化前后的静、动态特性变化规律。结果表明:变胞元非均匀排布优化后,最大的位移、应力、应变均明显减小,且激励频率等于第二阶固有频率时振动最为强烈。研究结论可为蜂窝结构变胞元排布的优化设计提供指导。

用于HTPB推进剂浆料的静态混合管数值模拟

端羟基聚丁二烯(HTPB)推进剂中固化剂和黏合剂的充分混合对推进剂性能至关重要,SK型静态混合管能实现高黏度流体的充分混合。采用Minilab微型双螺杆流变仪测量了推进剂浆料的黏切曲线。通过计算流体力学对应用于HTPB推进剂药浆的SK型静态混合管进行了数值模拟,分析了SK型静态混合管的入口流速、元件个数和元件长径比与压降和混合效果之间的关系。数值模拟表明,压降与入口流速成正比,与元件个数线性相关,45%以上的阻力损失都集中在混合管用于挤出成型的出口喷嘴处。8个混合单元可完成99.9%的混合,12个混合单元可完成99.99%的混合。长径比减小时,径向上的二次流加剧。长径比从0.5增加到1.25,可以在加强混合的同时降低能耗。

脊柱无创示踪装置在静态和术中动态环境下的临床精度研究

目的本研究旨在探讨新型无创示踪系统在静态和动态环境下的临床精度表现。方法该系统由无创示踪装置和光学导航设备组成。在静态环境下,使用术中C臂电子计算机断层扫描(computed tomography,CT)扫描脊椎模型,通过CT图像空间中的标记点进行实时自动化配准,测量无创示踪装置配准精度和8个体表验证点的配准精度。将无创示踪装置与连接于椎体的刚性示踪装置进行比较,测量椎弓根螺钉导针在体表下3~4 cm处螺钉入点位置误差和体表下8~9 cm处螺钉终点位置误差,以及导针整体规划路径与实际路径的角度误差。本研究中前期构建了呼吸运动下脊柱椎体运动模型以仿真术中椎体的动态环境,通过机械臂进行伺服模拟呼吸运动构建术中动态环境,并在术中同法测量动态环境下的无创示踪器临床精度。结果无创示踪器配准误差较小,静态环境下为(0.483±0.242)mm,动态环境下为(0.524±0.229)mm。无创示踪装置内部区域的配准误差低于外部区域的配准误差,静态环境下为[(0.472±0.202)mm vs(0.954±0.279)mm,P<0.001],动态环境下为[(0.516±0.188)mm vs(1.029±0.252)mm,P<0.001]。8条导针入路的骨表面入点精度高于骨内部终点精度,体表下3~4 cm处位置误差小于8~9 cm处,静态环境下为[(0.018±0.024)mm vs(0.061±0.061)mm,P=0.002],动态环境下为[(0.403±0.275)mm vs(0.938±0.640)mm,P<0.001]。导针入路的角度误差较小,静态环境下<0.25°,动态环境下<1.50°。结论在静态环境下,无创示踪器对体表区域和深部区域均保持较高位置精度和角度精度,在动态环境中,体表区域和深部区域的定位精度和角度精度降低,但仍在可接受的范围内。

新型钢坯修磨设备的静力学及动力学分析

钢坯因生产工序的原因其表面有氧化层及缺陷,故必须通过磨削的方法进行表面修磨。针对目前没有专用的设备对大型的方形钢坯料进行表面修磨的问题,设计了一种方形钢坯修磨设备,并利用ADAMS软件完成了运动学仿真验证。结果表明,修磨设备可同时平稳完成对两相邻面的打磨作业。利用有限元软件ANSYS,对修磨机进行受载下的应力分析、模态分析,并对结构进行了改进;根据简化运动学模型进行静力学分析,得到了所需输入驱动力矩,并对关键部件弹簧完成了选型。理论计算及仿真结果表明,此修磨设备能够高效地完成对大型方形钢坯表面的磨削任务。

RFreeTrack:基于差分相位全息图的RFID非接触式鲁棒定位系统

针对复杂室内环境非接触式RFID目标定位误差大的问题,提出了RFreeTrack系统,其使用商用RFID设备计算出目标反射信号,实现了复杂环境下高精度非接触式目标定位。首先,提出了一种基于时间序列相似度的搜索方法用于校准静态信号,从而显著增强了目标反射信号提取的鲁棒性。然后,提出了基于差分相位全息图的非接触式定位方法,排除阅读器天线位置的影响,提升了定位准确度,降低了系统的部署难度。最后,实现了一个高精度的非接触式定位系统原型。实验表明,在复杂环境中使用校准后的静态信号提取出的目标反射信号相位,相较于现有方法误差降低了68.8%。基于校准过的静态反射信号,在复杂环境中使用差分相位全息图的定位误差平均值为0.040 8 m,相较于现有方法提升了50.6%。

多向聚焦波作用下透水潜堤消波特性数值模拟研究

本文采用非静压模型NHWAVE建立高精度三维波浪数值水槽,对多向聚焦波作用下透水和不透水潜堤消波特性进行数值模拟研究。通过计算结果与实验数据的对比,验证了该模型模拟多向聚焦波产生传播及多孔介质内流动的能力,进一步考虑了有效波高、水深、谱峰周期和传播角度等因素对潜堤消波特性的影响。结果表明:潜堤对多向聚焦波的最大波幅、最大水位、沿水深平均最大流速和波能均有显著消减作用,且透水潜堤因孔隙介质的存在消波性能更好。随着有效波高增大,堤顶处波浪破碎点前移,不透水潜堤消波性能受波高影响较大。水深越大,潜堤消波性能越低。透水潜堤对长周期波浪消减效果较差。传播角度越小,聚焦位置处波幅越大,波浪非线性作用越强。研究结果可为我们进一步保护沿海设施免受极端海洋环境的影响提供一定的参考。

Paradiplomacy for Non-recognized States:Case of Palestine

This paper endeavours to elucidate the intricacies of Palestinian Paradiplomacy,focusing in the political impetus pioneered by its principle actors,namely the Palestine Liberation Organisation(PLO)and subsequently,the establishment of the Palestinian National Authority(PNA).Additionally,attention will be directed towards the creation of the Palestinian Ministry of Foreign Affairs(PMOFA)and its subsidiary,the Palestinian International Cooperation Agency(PICA),albeit briefly discussed.Drawing inspiration from Alexander S.Kuznetsov’s seminal work“Theory and Practice of Paradiplomacy:Subnational Governments in International Affairs”(2015),this paper tries to scrutinize the trajectory of Palestinian paradiplomacy and its evolutionary course over time.When it comes to activity and growth,Palestinian paradiplomacy has a unique profile.The way in which topics pertaining to nations are not yet recognized has a great deal of bearing on current discussions and academic research about urgent political concerns like the right to self-determination and human rights.The analysis of de facto states via the prism of paradiplomacy naturally arises from the dominant state recognition procedures in international politics.

非爆破机械钻进联合静力膨胀裂切技术应用研究

采用钻爆法进行非煤矿山巷道掘进的过程中,往往会产生诸多安全隐患。随着机械装备的快速发展,非爆破机械采矿逐渐成为非煤矿山开采的主流研究方向。为解决某矿山下向进路充填采矿时,首采层采场回采难度大、回采周期长、支护难度高和作业安全性差等问题,提出非爆破机械钻进联合静力膨胀裂切的技术思路。首先,通过数值模拟的方式进行机械钻进静态裂切孔网参数优化,确定裂切孔网方案,然后进行现场试验检验技术效果。结果表明,非爆破机械钻进联合静力膨胀裂切技术应用良好,能够切实解决矿山面临的生产难题。

非营利性网约车平台定价策略:静态定价vs.峰值定价

本文以社会福利最大化为目标,分别构建了静态定价和峰值定价两种定价策略下非营利性网约车平台的决策模型,对比分析不同定价策略对平台的最优定价、社会福利、消费者剩余和司机剩余的影响。在此基础上,进一步分析了社会福利最大化与利润最大化下网约车平台采用峰值定价时的差异表现。研究发现:(1)当存在服务需求不确定性时,利润最大化的网约车平台选择峰值定价不劣于静态定价;(2)与利润最大化为目标的网约车平台不同,社会福利最大化的非营利网约车平台除了在需求波动非常大情形下考虑使用峰值定价外,应使用静态定价;(3)利润最大化的网约车平台采用峰值定价可能造成供应短缺,而社会福利最大化的网约车平台使用峰值定价总能使得供需匹配,并带来消费者剩余的增长;(4)当出现低需求的概率适中或平台总是处于高需求时,使用静态定价的社会福利最大化的平台可以比利润最大化的平台更好地匹配供需或者使单个消费者获得更高的效用,从而具有更高的消费者福利。上述结论可为各级政府制定网约车平台服务政策方案提供重要的理论支撑和决策参考。

基于向量式结构力学的结构非线性静力分析

向量式结构力学是基于向量力学提出的广义而系统化的结构数值分析理论,特别适合求解非线性、大变形及不连续问题。本文基于向量式结构力学基本原理建立了桁架结构非线性静力分析方法,给出详细的计算公式和计算步骤。给出三个数值算例,通过与ANSYS计算结果的对比分析,验证了向量式结构力学对非线性静力分析的适用性和精度。

双扭线流量管测量方法数值研究

围绕双扭线流量管测量方法中,测量截面静压不均匀和附面层修正方法两个影响因素,采用数值仿真的方法模拟了双扭线流量管试验测量,分析了测量截面静压不均匀和附面层修正方法对流量测量的影响。结果表明:静压测量截面距离双扭线切点越近,测量截面静压不均匀性对主流区流量计算偏差的影响越大,可通过建立静压关联关系式进行修正;试验中采用积分法计算附面层流量时,近壁区速度分布与线性分布存在差异,导致第1个测点与壁面间区域积分流量存在偏差,可按指数分布规律重构近壁区速度进行修正。

轴流压气机试验台排气蜗壳关键设计因素对周向反压不均匀度的影响

本文采用等平均速度流动方法对轴流压气机试验台用径向排气蜗壳进行设计,主要研究了蜗壳截面形状、蜗壳轮廓线不同渐开方法、蜗壳0°相位截面面积取值对排气系统周向反压不均匀度的影响。同时,提出了一种在蜗壳0°相位截面增设隔板,抑制排气系统进气旋流角对排气系统周向反压不均匀度影响的方法。

基于静压恢复规律的间抽制度研究

在油田生产过程中,间抽是解决低产低效、举升单耗高等问题的有效手段,不仅可以提高泵的充满程度,还可以提高系统效率,亟需制定合理的间抽制度。以油井的静压测试曲线为基础,通过研究IPR曲线类型、液面变化规律、沉没度与泵效的关系,IPR曲线存在有拐点和无拐点2种类型,液面变化先快后慢,恢复至原液面抽汲时间远长于停机时间,泵效在一定沉没度范围内基本不变,为提高间抽效率,采取调大参数间抽。以产量不变为前提,无拐点井根据液面恢复速度确定停机时间,不同参数条件下的沉没度、泵效,计算启抽时间;有拐点井以拐点流压为基准,确定流压波动范围,从而得出对应启停时间。现场实施450口井,液面波动在50 m左右,系统效率提高5.27%,累计节电340.93×10^(4) kWh。基于液面变化规律制定的调大参数间抽制度,液面波动较小,节能效果好;同时利用不停机间抽技术能够实现短时、高频间抽,有效平衡产量与能耗的关系,节能潜力进一步释放,确保了油井高效举升,提高整体开发效益。

星型-三角形负泊松比结构的面内压缩刚度可调控特性

通过准静态面内压缩试验揭示星型-三角形结构(star-triangular honeycomb, STH)的刚度可调控特性。利用有限元模拟的方法研究非均匀壁厚STH的面内压缩刚度可调控机制,分析不同类型胞壁厚度比(t_(1)=t_(3))/t_(2)及胞壁角对其面内压缩刚度的影响。结果表明,STH在面内压缩载荷下呈2个线弹性阶段,且强化刚度比初始刚度显著增大。适当地增大内凹胞壁和垂直胞壁的厚度可同时提高STH的初始刚度及强化刚度;当(t_(1)=t_(3))/t_(2)>1.575后,初始刚度仍持续增大,而强化刚度反而逐渐减小,最终不再具有强化刚度阶段。胞壁角α≤30°时,增大胞壁角可提高STH的初始刚度及强化刚度,反之,初始刚度及强化刚度对应的应变随胞壁角的增大逐渐增大,而强化刚度逐渐减小并趋于消失。该研究将为可调节刚度负泊松比结构的设计提供新的思路。

考虑半高连续填充墙约束的框架柱抗震性能研究

为研究实际震害,探讨半高连续填充墙约束下的钢筋混凝土框架柱的抗震性能,设计了两组两跨框架模型进行拟静力试验,对比分析半高连续填充墙对柱抗震性能的影响。使用Perform-3D软件建立宏观数值模型,填充墙构件使用对角斜撑杆件模拟,考察半高连续填充墙的约束效果。分析结果表明:填充墙破坏增加结构耗能,滞回曲线更饱满且具备较优的延性,填充墙对柱有明显约束作用,改变了柱构件原本的破坏模式;数值模拟结果与试验结果一致。鉴于填充墙对结构受力变形影响较大,将其视为非结构构件,忽略其对整体结构的作用是不妥的。