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关键词： 轨道车辆   抗涂鸦   粉末涂料   表面张力  

摘要： 对阿尔斯通和法国铁路公司关于列车内部件涂鸦物清除标准进行了梳理,并通过试验开发了一款适用于涂装轨道车厢内部件的热固性粉末涂料,该涂料成膜后对清洁试剂具有较好的耐性,且清除涂鸦物功效性较好,满足ALSTOMDTRF 150612技术标准,并通过在配方中添加1%的抗涂鸦助剂,所制得的涂膜具有一定的抗涂鸦性能.

关键词： 钨极氩弧焊   多组元活性剂   表面张力   熔深   流速  

摘要： 准确获取焊接条件下熔池金属表面张力的基础数据对深入理解焊接过程中熔池金属流动及传热机制、焊缝缺陷形成等具有重要意义,但实时测量十分困难.采用激光视觉法测量了单一组元(TiO2,CaF2)及二组元(30%TiO2+70%CaF2,70%TiO2+30%CaF2)活性剂下304不锈钢脉冲钨极氩弧焊熔池振荡频率,并根据特定模式下熔池特征频率与表面张力的解析模型计算了熔池金属表面张力,分析了不同组元活性剂对熔池金属平均表面张力的影响规律,在此基础上研究了不同组元活性剂对焊缝熔深的影响和增加熔深的机理.结果表明,TiO2能够改变熔池金属表面张力温度梯度,使熔池金属流动方向发生变化,CaF2能够降低熔池金属表面张力绝对值,使熔池金属流速增加;二组元活性剂增加熔深是熔池金属流速增加和表面张力温度梯度改变共同作用的结果.

关键词： 卡门涡街   CFD   CAE   共振  

摘要： 空调器结构件的流致振动会引起极大的异常噪声问题,极大地影响用户体验和产品的声品质的提升,甚至会破坏结构的强度并引起安全问题。对一种空调器出风口防护网流致振动噪声问题进行研究,首先通过CFD流场仿真的方法对于防护网圆柱绕流卡门涡脱特性进行研究;然后通过CAE分析的方法对防护网进行结构模态分析,确定该防护网异常噪声是流致激励引起结构共振导致;最后对防护网进行结构优化从而改善了该异常噪声问题。

关键词： 钼矿   包裹体特征   成矿条件   浅成   随枣北部  

摘要： 随枣北部处在东秦岭钼矿聚集区和西大别钼矿聚集区之间的桐柏造山带,具有良好的钼矿成矿环境条件及找成矿前景。随枣北部钼矿流体包裹体类型、均一温度及盐度、密度反映成矿流体属岩浆热液与大气降水混合的产物,发生过沸腾和分离作用,钼的富集与流体的沸腾作用关系密切,主要成矿温度在290~390℃之间,属高温成矿环境,成矿压力为9.06~72 MPa,成矿深度为0.91~6.83 km,属浅成环境。

关键词： 印度尼西亚   戴里铅锌矿集区   Sedex型   流体包裹体   硫铅同位素  

摘要： 戴里铅锌矿集区位于印度尼西亚苏门答腊岛西北部,是一个主要产于页岩、具有巨型规模的Sedex型铅锌矿。通过系统的流体包裹体测试及H、O、S、Pb等同位素分析,以对其成因进行约束。分析结果表明:①戴里铅锌矿流体包裹体均一温度范围为189~315℃,峰值为220~240℃;②δD V-SMOW值范围为-68.7‰^-76.4‰,平均为-72.9‰,δ^18 O V-SMOW值范围为+5.9‰^+19.5‰,平均为+16.6‰;③黄铁矿δ34 S CDT值为正值,集中分布在+25.49‰^+26.36‰之间;④铅同位素显示较高的μ值(9.92~10.17,平均值为10.04)和ω值(38.06~40.51,平均值为39.26)。该矿床成矿流体温度为中温(220~240℃),成矿流体可能以岩浆水为主,有少量浅源水的加入,硫、铅均为单一来源,其中硫主要来自海水,铅来源于上地壳。

关键词： 低表面张力   活性水压裂液   氟碳表面活性剂   润湿角  

摘要： 研究了低表面张力活性水压裂液的配方并进行了性能测试与评价.该活性水压裂液以KC1为防膨剂,表面活性剂为助排剂.研究了防膨剂KCl,表面活性剂的组成对活性水压裂液的表面张力,润湿角的影响,结合成本分析得到该活性水压裂液的配方.对该活性水压裂液进行表面张力、降阻率、防膨率等性能进行综合评价,表明该压裂液各方面性能均符合要求.

关键词： Bose-Einstein condensation   dipolar Bose gases   rotons   superfluid density  

摘要： Using the Green's function approach, the density-density correlation function and the dielectric function in the random-phase approximation for a quasi-two-dimensional (quasi-2D) dipolar Bose gas are derived. From the pole of the density correlation function, by considering thermally induced roton-like excitations, the excitation spectrum of the system is calculated. It is shown that the position and depth of the roton minimum of the excitation spectrum are tunable by changing the temperature. To show how the position of the roton minimum influences the phenomenon of superfluidity, the superfluid density of the system is obtained and it is shown that the interplay of the thermal rotonization, contact and dipole-dipole interaction (DDI) can affect the superfluid fraction of a quasi-2D Bose gas. It is found that contact, DDI interactions, and thermally induced rotons enhance the fluctuations and reduce the superfluid density. In the absence of DDI and thermally induced rotons, the usual T-3 dependence of superfluid density in 2D is obtained and the correction T-4 term arises from DDI. It is shown that if the roton minimum is close to zero, the thermally induced rotons change the linear temperature dependence of the superfluid fraction, leading to a transition to nontrivial supersolid phase.

关键词： Hardware   Software   Switches   Throughput   Machine learning   Prototypes   Network function virtualization   Network function virtualization   machine learning   software-defined networks   performance management  

摘要： With the move from traditional hardware appliance based network functions to Network Function Virtualization, software development is decoupled from the hardware. However, as a network function is no longer optimized for hardware, beneficial features of networking hardware may not be used any more. Solutions such as SDN or NIC offloading aim to overcome this antipodes by integrating networking hardware into the packet processing pipelines. On the one hand, offloading traffic of network functions to hardware can increase throughput and reduce resource consumption. On the other hand, the number of parallel flows in a network can be very high, exhausting the capacity of the tables of the networking hardware and force the system to fall back to software processing. Fortunately, it is known that a large portion of the flows in the Internet are mice flows, whereas the majority of the traffic is constituted by elephant flows. If the elephant flows can be detected efficiently, the hardware tables can be used more efficiently as a larger share of the traffic can be offloaded. We introduce a machine learning based approach that takes its decision with the first packet of a flow. A fundamentally different approach is using packet sampling for the offloading decision. We are evaluating both approaches in terms of complexity, offloaded share of the traffic and table occupation. The results show that a machine learning based offloading decision is possible with the first packet. The sampling approach only reaches a comparable performance at very high sampling rates.

关键词： Vorticity equation   Stream function   Bounded domain  

摘要： The main purpose of this work is to provide a Hilbertian functional framework for the analysis of the planar incompressible Navier-Stokes (NS) equations either in vorticity or in stream function formulation. The fluid is assumed to occupy a bounded possibly multiply connected domain. The velocity field satisfies either homogeneous (no-slip boundary conditions) or prescribed Dirichlet boundary conditions. We prove that the analysis of the 2D Navier-Stokes equations can be carried out in terms of the so-called nonprimitive variables only (vorticity field and stream function) without resorting to the classical NS theory (stated in primitive variables, i.e. velocity and pressure fields). Both approaches (in primitive and nonprimitive variables) are shown to be equivalent for weak (Leray) and strong (Kato) solutions. Explicit, Bernoulli-like formulas are derived and allow recovering the pressure field from the vorticity fields or the stream function. In the last section, the functional framework described earlier leads to a simplified rephrasing of the vorticity dynamics, as introduced by Maekawa (Adv Differ Equ 18(1-2):101-146, 2013). At this level of regularity, the vorticity equation splits into a coupling between a parabolic and an elliptic equation corresponding respectively to the non-harmonic and harmonic parts of the vorticity equation. By exploiting this structure it is possible to prove new existence and uniqueness results, as well as the exponential decay of the palinstrophy (that is, loosely speaking, the H-1 norm of the vorticity) for large time.

关键词： Load balancing   Big data flow   Classification   Heterogeneous computing   Software definition networks  

摘要： Distributed network architecture of heterogeneous computing faces with such problems as strict performance constraints of network control, unpredictable mapping relationship between computing data algorithms of different mobile terminals and inconsistency between computing algorithms and link control of data networks. In order to solve the above problems, we begin with software definition network architecture and load balancing algorithm for heterogeneous computing, and gradually improve the real-time and reliability of heterogeneous computing. On the one hand, the heterogeneous computing data of fog node and cloud computing system are distributed. The centralized service of software-defined network combines with distributed computing of mobile edge terminal and its subnet. On the other hand, we define the centralized information and distributed scheduler of the network. In addition, we deploy the optimal assignment of data sharing and heterogeneous computing tasks in real time with ellipse-partitioned area as the object. A series of algorithms for classifying and assigning heterogeneous computing data streams in software-defined networks are designed to achieve the optimal balance among load balancing, minimum classification of large data streams, minimum resource occupation and time constraints. Experimental comparison compared and evaluated the Load Balancing with big data stream (LBBS), Load Balancing with Heterogeneous Computing (LBHC) and the proposed LBBHD. Compared with the other two algorithms, the proposed algorithm improves workload skewness, throughput and load balancing error respectively about 2.1%, 1.96%, 2.9%, 2.2%;5.57%. 2.51%.