Computer-based sensing and visualizing of metal transfer mode in gas metal arc welding

Using Xenon lamp lights to overcome the strong interference from the welding arc, a computer-based system is developed to sense and visualize the metal transfer in GMAW. This system combines through-the-arc sensing of the welding current and arc voltage with high speed imaging of the metal transfer. It can simultaneously display the metal transfer processes and waveforms of electrical welding parameters in real-time The metal transfer videos and waveforms of electrical welding parameters can be recorded. Metal transfers under various welding conditions have been investigated with the system developed.

Research on arc characteristics and metal transfer modes of ultrasonic assisted GMAW process

Ultrasonic assisted GMAW （U-GMAW） method is a novel process, which combines the ultrasonic wave with gas metal arc welding to improve the process stability and weld quality. The U-GMAW system is developed and the ultrasonic wave is applied by means of acoustic radiation. The arc characteristics and metal transfer modes are studied in comparison with conventional GMAW process. The arc plasma is compressed and the arc length is shorter than that in conventional GMAW process after the ultrasonic is applied onto the arc. The parameter range of short-circuiting mode is extended and the range of unstable transfer is minimized. The changes in arc characteristics are responsible for changes in metal transfer modes.

The New Changes in Rural Labor Transfer Mode under New Urbanization: Based on the Survey of 10 Villages in Guizhou Province

With the full-speed development of economy,the new urbanization has been accelerated in Guizhou Province in order to make the people reach a well-off standard of living by 2020. From the whole society,the key point is the development of the rural economy,and the development of the rural economy depends on the economic development of rural households. The income from rural labor force transfer has become the main income source and accounts for more than half of rural household income,which will play a major role in survival and development of rural households.

Digital television transmission based on asynchronous transfer mode

This paper introduces a method to realize digital television transmission based on asynchronous transfer mode (ATM), a technology based on fast packet switching. Choosing the integral multiple length of an ATM cell payload to equal to the length of an MPEG transport stream packet, an MPEG transport stream packet can be inextenso loaded by several ATM cells and trans-formed into ATM cells. Using ATM virtual connection technology and B-ISDN, the interoperability between ATM and DTV may be realized, and DTV signal transmission may also be realized finally.

Thermal runaway evolution of a 280 Ah lithium-ion battery with LiFePO_(4) as the cathode for different heat transfer modes constructed by mechanical abuse

Lithium iron phosphate batteries have been increasingly utilized in recent years because their higher safety performance can improve the increasing trend of recurring thermal runaway accidents.However,the safety performance and mechanism of high-capacity lithium iron phosphate batteries under internal short-circuit challenges remain to be explored.This work analyzes the thermal runaway evolution of high-capacity LiFePO_(4) batteries under different internal heat transfer modes,which are controlled by different penetration modes.Two penetration cases involving complete penetration and incomplete penetration were detected during the test,and two modes were performed incorporating nails that either remained or were removed after penetration to comprehensively reveal the thermal runaway mechanism.A theoretical model of microcircuits and internal heat conduction is also established.The results indicated three thermal runaway evolution processes for high-capacity batteries,which corresponded to the experimental results of thermal equilibrium,single thermal runaway,and two thermal runaway events.The difference in heat distribution in the three phenomena is determined based on the microstructure and material structure near the pinhole.By controlling the heat dissipation conditions,the time interval between two thermal runaway events can be delayed from 558 to 1417 s,accompanied by a decrease in the concentration of in-situ gas production during the second thermal runaway event.

Research on the Heat Transfer Characteristics of a Loop Heat Pipe Used as Mainline Heat Transfer Mode for Spacecraft

An experimental research is conducted on the heat transfer characteristics of a loop heat pipe(LHP)used in the"mainline"heat transfer mode for spacecraft platform thermal control.The heat from multiple instruments scattered in different locations is collected by thermal control techniques such as axially grooved heat pipes and then transmitted to the radiant surface for dissipation through the LHP in an unified way.The research contents include the start-up characteristics,the operational stability characteristics,the operational blocking characteristics,the continuous blocking characteristics,the heat transfer capability,the thermal resistance,and the dynamic response characteristics under the change of the heat sink temperature.The results show that the higher the auxiliary starting power is,the easier it is to start the LHP;the higher the input power of the thermoelectric cooler is,the more beneficial it is to speed up the stabilization of the vapor-liquid interface in the condenser;the higher the blocking power,the shorter the blocking time of the LHP;the LHP can be operated stably within the heat sink temperature alteration process;the heat transfer ability is higher than 500 W with a systematic thermal resistance of 0.037℃/W.

Heat Transfer and Mode Transition for Laser Ablation Subjected to Supersonic Airflow

When laser ablation is subjected to supersonic flow, the influence mechanism of airflow on laser ablation behavior is still unclear. A coupled thermal-fluid-structure model is presented to investigate the influence of supersonic airflow on the development of a laser ablation pit. Results show that the aerodynamic convection cooling effect not only reduces the ablation velocity but also changes the symmetry morphology of the ablation pit due to the non-uniform convective heat transfer. Flow mode transition is also observed when the pit becomes deeper, and significant change in flow pattern and heat transfer behavior are found when the open mode is transformed into the closed mode.

Multipartite Entanglement Transfer from Multi-Mode Coherent State to Spin Qubits

到旋转 qubits 的从连续可变系统的多国参加的纠纷转移被调查。我们选择多模式是的协调的地连续的可变的地。qubits 不能从多模式为结束的状态获得分成三部分的纠纷到 GHZ 状态，这被发现协调的地。而且， qubits 获得的能力为近到 W 状态的状态的分成三部分的纠纷和从连续可变系统的由两部组成的纠纷被取决于多模式的阶段协调的地。

Entanglement Transfer from Two-Mode Squeezed Vacuum State Field to Two Spatially Separated Atoms in Two-Photon Processes

我们在二光子的过程从二模式的挤压的真空状态地在纠纷转移上调查空移动的影响到二个空间地分开的原子。我们的结果证明空移动在如此的纠纷转移起一个重要作用。我们发现当空移动参数 r 是小的时，在二个原子之间的纠纷的度与首先增加压榨的参数 ξ 增加，并且在完成它的最大的价值以后，纠纷的度将与增加 &#958 减少到零；当时为大 r， E 将与增加 ξ 增加。

Study of engaged performance regulation in controlled transfer clutch of 4WD car based on genetic sliding mode control

This paper investigates an approach to improve the engagement quality of controlled transfer clutch mode in 4 wheel drive(WD) car from three considerations of reducing friction,smoothening responsiveness and alleviating jerk.The method utilizes an improved sliding mode control with genetic algorithm instead of simplified mode to determine appropriate values of parameters in control close- loop.The simulation results show that the method is effective for improving the engagement quality of coupling satisfying different design needs for 4WD car,as well as robustness even if input torque is changed at a certain range.

多场景下基于传感器的行为识别

针对基于传感器的行为识别任务中识别场景单一且固定的问题,提出一种多场景下基于传感器的行为识别迁移模型,由基于传感器的动态感知算法(dynamic perception algorithm,DPA)和自适应场景的行为识别迁移方法(adaptive scene human recognition,AHR)两部分组成,解决在固定场景下对传感器的依赖性以及在场景转换时识别模型失效的问题。DPA提出两阶段迁移模式,将行为识别阶段和模型迁移阶段同步推进,保证模型在传感器异动发生后仍能持续拥有识别能力。进一步提出AHR场景迁移方法,实现模型在多场景下的行为识别能力。实验验证该模型具有更优的适应性和可扩展性。

S型异质结光催化剂ZnFe_(2)O_(4)/WO_(3)的构筑及光催化还原CO_(2)性能

通过在WO_(3)纳米片表面负载ZnFe_(2)O_(4)纳米颗粒,构建了一系列S型异质结光催化剂ZnFe_(2)O_(4)/WO_(3),并研究了其光催化CO_(2)还原性能。在没有助催化剂和牺牲剂的条件下,所制备的ZnFe_(2)O_(4)/WO_(3)复合材料可对CO_(2)与水蒸汽进行光催化反应。优化后的材料光照5 h后CO_(2)还原产物CO和CH_(4)的产量分别为7.87和4.88μmol·g^(-1)。相对于单相组分,CO和CH_(4)的产量明显提高。光催化活性的提高,归因于ZnFe_(2)O_(4)和WO_(3)异质结的形成以及光生载流子的S型电荷传输模式。

Effect of Different Blood Cycle Modeson Mass Transfer of Artificial Kidney

Based on the one-dimensional and unsteady-state Krogh model, this paper investigates mass transfer of artificial kidney under three blood cycle modes during the course of hemodialysis. The variations of the permeable solute clearance with increasing time and the dialysis time with increasing blood flux are simulated in detail,and then one optimal blood cycle mode is acquired. The results are very important to improve the clinical dialysis efficiency of artificial kidney.

高校图书馆服务乡村振兴的知识信息转移模型探讨

[目的/意义]为了更好地服务乡村振兴战略,高校图书馆挖掘已有资源潜力,服务乡村振兴的知识信息转移,以期提高农民的文化与信息素质、提高农业生产力、丰富农民精神与物质生活,值得探讨。[方法/过程]本文分析了影响农民吸收知识信息的主要原因,高校图书馆服务乡村振兴知识信息转移的变化特点,目前高校服务乡村振兴的主要路径模式及不足。为更有效做好对大多数农民的知识信息转移服务,笔者选取高校图书馆、农村图书馆、涉农企业、农民作为从高校图书馆发出到农民接收的知识信息转移的过程主体,探讨构建了两条知识信息转移的新路径模型和构建了4种知识信息转移的过程模式。[结果/结论]提出了创新高校图书馆体制机制,建设“三农”精准知识资源库与传播系统,提升乡村人员获取知识信息能力,拓宽知识信息转移渠道,缩小知识信息转移情境差距等对策,以实现高效将知识与信息转移给农民,为中国实施乡村振兴作贡献。

适应并离网模式切换的DFIG电磁暂态仿真建模

目前,常用的商业仿真软件中的双馈式感应发电机(double-fed Induction Generator,DFIG)模型通常不支持离网运行模式,难以实现风力发电系统由离网到并网的全过程电磁暂态仿真,对电力系统仿真分析工作带来极大不便。研究适应并离网模式切换的DFIG电磁暂态仿真建模方法。基于模块化思想分别对风力机、异步电机、变流器以及断路器进行建模,在系统组装形成DFIG风力发电系统电磁暂态仿真模型。提出了适应并离网模式切换的DFIG受控源等效电路模型和离散时间域实现方法,通过设计状态变量矩阵元素的截取和扩充算法实现了模型在并离网模式下的无缝衔接。在MATLAB/Simulink中搭建DFIG发电系统模型对所提方法和模型进行验证,仿真结果表明,所提建模方法能够很好地支持DFIG离网运行模式,实现DFIG由离网到并网的全过程电磁暂态仿真。

基于深度迁移学习的车辆悬架高频异常振动故障诊断

在车辆悬架故障诊断过程中,深度学习故障诊断模型在面对少量样本数据时模型训练效果不佳,导致诊断模型的接收者操作特性曲线(receiver operating characteristic,ROC)的曲线下面积(area under curve,AUC)较小的问题,利用经验模态分解(empirical mode decomposition,EMD)方法,对采集的车辆悬架高频振动信号进行分解处理,根据每个经验模态分量(intrinsic mode functions,IMF)的能量,提取高频异常振动故障特征,构建了基于深度迁移学习的诊断模型;以深度卷积神经网络算法为基础,对小样本特征矢量信息进行故障知识迁移处理,通过参数微调更新权值,优化故障诊断模型。实验结果表明:优化后模型的AUC值为0.89,模型故障诊断结果具有较高准确性。

智能反射面辅助认知无线携能通信次用户网络吞吐量优化

为了提高认知无线携能通信(Simultaneous Wireless Information and Power Transfer,SWIPT)网络的频谱利用率并改善其能量受限情况,本文研究智能反射面(Intelligent Reflecting Surface,IRS)辅助的认知SWIPT网络,其中主用户网络以覆盖方式与次用户网络共享频谱,而次用户发射机同时为主用户发射机供能并与次用户接收机传输信息。提出次用户网络吞吐量优化算法,在满足次用户发射机的最大发射功率约束、主用户网络的最小吞吐量约束、总时隙约束以及智能反射面移约束的条件下,联合优化次用户发射机的波束成形矢量、时隙分配和智能反射面反射相移,最大化次用户网络吞吐量。该问题的优化变量相互耦合并且结构高度非凸,难以直接求解。所提算法采用交替优化、半正定松弛以及连续凸逼近方式,将原问题转化为三个子问题进行迭代求解。仿真结果表明与已有基准方案相比,所提算法能明显提高次用户网络的吞吐量。

综合考虑材料热各向异性与多种传热方式的磁性元件热阻网络精准模型

磁性元件正在向高频化、小型化、高功率密度的方向发展,随着功率密度的提高,散热已成为影响器件可靠运行的关键因素,因此对磁性元件的热分析提出更高的要求。传统的热分析模型存在运算时间长、传热方式单一等问题,该文引入已有研究中提出的三轴九热阻网络模型,在此基础上添加热对流与热辐射两种传热方式,综合考虑材料热各向异性与热传导、热对流、热辐射。并通过精细划分元件温度计算子区域、实际器件损耗场分析、热电耦合迭代提高模型的计算精度,提出一种更加完善的三轴十五热阻网络模型,基于该模型对实际磁性器件建模,验证了该模型的准确性,并于最后提出一种通用的针对EE、EI、UU等典型磁心构成的磁性元件的热阻网络建模方法。

Charge-Transfer and SERS Coupling on TiO2

We report the SERS enhancements of Raman forbidden surface modes of TiO2 in different sized TiO2 crystals. This current study utilizes the relationship between the vibronic coupling and the degree of charge-transfer to explain the differences of Surface Enhanced Raman Scattering (SERS) enhancements. Our study shows a direct correlation between the degree of charge-transfer and vibronic coupling. This relationship suggests that charge-transfer between the N-719 dye and TiO2 due to vibronic coupling plays a fundamental role in SERS enhancements. Furthermore, this study shows a strong dependence of the enhancements of the N-719 dye molecular modes to that of the surface modes. This indicates that the mechanism that governs the enhancements of the surface modes in TiO2 crystals most likely also dictates the enhancements of the N-719 dyes.