摘要：In FLAC ^(3D),cable element or modified pile element can be used to build slope anchoring ***,the difference between the two structural elements and their influence on the calculation results have not been studied in *** order to solve this problem,the Xiashu loess slope anchoring models based on cable element and modified pile element were constructed respectively.A variety of anchoring schemes were designed by orthogonal experiment method,and then they were brought into the model for calculation and the calculation results were analyzed by range analysis and variance *** results show that the modified pile element can bear the bending moment and reflect the strain softening property of the *** the perspective of slope safety factor,the anchorage length and anchor bolt spacing are the main factors affecting the stability of the slope,and the anchorage angle is the secondary *** grout in cable element is assumed to be an elastic-perfectly plastic material,so the safety factor of the slope can be significantly increased by increasing the length of the anchor *** will bring potential risks to the slope treatment ***,in the calculation of the slope anchoring model,the modified pile element is more suitable for simulating the anchor bolt.

摘要：利用Peck公式计算双线隧道开挖引起的地表沉降时,有多个参数会影响到计算结果的大小与沉降曲线的形状。从数学角度对隧道轴线埋深h和两隧道间距L的比率及沉降槽宽度参数K对地表沉降曲线的影响进行研究,得到以下结论:在h/L比率逐渐增大的过程中,地表沉降曲线变化过程为较陡峭的W型—较平缓的W型—∪型—U型—V型;相同比率下的地表沉降曲线都呈现相同的型式,与隧道埋深无关;在K=0.600的情况下,沉降曲线由W型向U型转变,h/L的临界值为0.825,而后发现在不同K值下,存在h/L临界值使得不同埋深下的沉降曲线都呈现U型,得到了沉降槽宽度参数K与其对应h/L临界值的最优拟合方程。基于h/L临界值的分析结果,提出了双线隧道远近界线的判别公式,并与现有方法及规范进行对比,结果表明判别公式能较好地界定双线隧道远近距离。同时,对Peck公式预测隧道开挖引起地表沉降的机理进行了推测,并利用颗粒流软件对隧道开挖进行模拟,结果表明压力拱曲线符合高斯曲线。研究成果可为双线浅埋隧道设计、施工提供依据。

摘要：将微视频的创意及快速制作的特点与基础化学实验教学相结合,并以此为应用案例,探讨微视频技术在基础化学实验教学中的应用。微视频技术的应用有助于提升学习过程的趣味性、互动性,规范实验操作,进行探索性学习;同时促进学生之间的交流学习,深刻理解和掌握知识点,提升实验实践教学环节的投入产出效率。

摘要：The Accelerator Driven Sub-critical(ADS)system is a strategic plan to solve the nuclear waste problem for nuclear power plants in ***-energy particle accelerators and colliders contain long strings of superconducting devices,superconducting radio frequency cavities,and magnets,which may require cooling by 2 K superfluid helium(HeliumⅡ).2 K superfluid helium cryogenic system has become a research hot spot in the field of superconducting *** this study,the ADS Injector-I 2 K cryogenic system is examined in *** cryogenic system scheme design,key equipment,and technology design,such as the 2 K Joule–Thomson(J–T)heat exchanger and cryomodules CM1+CM2 design,are examined,in addition to the commissioning and operation of the cryogenic *** ADS Injector-I 2 K cryogenic system is the first 100 W superfluid helium system designed and built independently in *** ADS proton beam reached 10 Me V at 10 m A in July 2016 and 10 Me V at 2 m A in continuous mode in January 2017 and has been operated reliably for over 15,000 h,proving that the design of ADS Injector-I 2 K cryogenic system,the key equipment,and technology research are reasonable,reliable,and meet the *** research into key technologies provides valuable engineering experience that can be helpful for future projects such as CI-ADS(China Initiative Accelerator-Driven System),SHINE(Shanghai High Repetition Rate XFEL and Extreme Light Facility),PAPS(Platform of Advanced Photon Source Technology),and CEPC(Circular Electron-Positron Collider),thereby developing national expertise in the field of superfluid helium cryogenic systems.

摘要：针对多弹三维协同攻击机动目标的要求,提出一种基于网络同步原理的协同制导方法.该算法给出了导弹3个方向的速度,并基于运动学关系转化为总速度、弹道倾角和弹道偏角指令.基于反步法将控制器设计过程转化为3步,分别为速度及弹道角子系统、气动角子系统和角速率子系统设计,各子系统采用滑模控制.控制器设计中采用扩展状态观测器对气动参数摄动和外部扰动进行估计,并在控制器中进行补偿.仿真结果验证了控制器的跟踪特性及导弹的协同攻击效果.

摘要：随着车辆保有量的不断上涨,环境的不断恶化,控制车用燃油已成为北京市交通领域节能减排工作的重要措施之一.私人小客车作为车用燃油的主要用户,由于数量庞大,消费自主性较强,目前无法采用全样统计的方式获取其燃油消耗,仅能依靠抽样的方式,利用样本推算其整体燃油消耗.因此,为获取可靠的燃油消耗样本,准确反映全市私人小客车燃油消耗水平,明确能耗显著影响因素和设计科学的分层抽样框架成为了关键.本文利用北京市现有私人小客车能耗调查数据,通过构建计量回归模型分析私人小客车能耗关键影响因素;利用计量学中引入虚拟变量的处理方法,提出了分层抽样框设计原理和阈值划分模型,最终形成分层抽样框架.

摘要：换热器性能的提高有利于提高能源利用效率。本文研究了广义辐射传热规律[q∝△(T^n)]下与外界环境间存在热漏的换热过程,应用平均最优控制理论导出了过程[火积]耗散最小时的最优性条件。基于普适的优化结果,进一步得到了牛顿(n=1)、线性唯象(n=-1)、辐射(n=4)以及一类混合传热规律下的特例结果,并与热流率和热流体温度分别为定值的常规传热策略进行了比较。给出了数值算例,揭示了传热量和热漏对换热器最小[火积]耗散及相应热、冷流体温度最优分布规律的定性与定量影响规律,明晰了有热漏条件下热流率和热流体温度分别为定值时的两种传热策略的优劣性。本文结果可用于指导实际换热装置的优化设计。

摘要：对一类普适传质规律等温节流过程进行了研究,应用最优控制理论导出了对应于过程质量积耗散最小时最优性条件,然后基于普适优化结果导出了传质规律[g∝(p)m]和线性传质规律[g∝(μ)]等各种特例下的优化结果,并与熵产生最小、压力之比为常数和压力之差为常数等各种传质策略下的结果进行了比较,给出了[g∝(p)1/2],[g∝(p)]和[g∝(μ)]等各种特例下的数值算例.本文的研究结果对于实际节流过程和设备的最优设计与运行具有一定的理论指导意义.

摘要：建立了存在热漏的换热器的传热过程模型.假定热流体与冷流体间的传热以及冷流体与外界环境间的热漏均服从牛顿传热定律,在冷流体净传热量一定的条件下,应用最优控制理论导出了换热过程(火积)耗散最小时热流体温度和冷流体温度的最优构型,并将最优路径分别与热流体温度一定和热流率一定的传统传热策略进行了比较.研究结果对于实际换热器的优化设计和最优运行具有一定的理论指导意义.

摘要：首次提出并设计了横向冲刷式降膜湿法脱硫反应器,并采用翅片管束作为降膜的载体.建立了液相侧传质-反应模型和横向冲刷降膜式脱硫传质模型,通过对模型的分析求解得到了反应器出口浆液的pH值以及浆液中H2SO3,HSO3-和SO32-的离子浓度随管束高度变化的规律,计算值与试验值的对比显示了良好的一致性,说明本模型对于液相侧传质-反应过程的求解是一种有效的方法,这将为横向冲刷式脱硫反应器的设计和优化提供理论上的支撑.