Numerical Analysis on Temperature Distribution in a Single Cell of PEFC Operated at Higher Temperature by1D Heat Transfer Model and 3D Multi-Physics Simulation Model

This study is to understand the impact of operating conditions, especially initial operation temperature (Tini) which is set in a high temperature range, on the temperature profile of the interface between the polymer electrolyte membrane (PEM) and the catalyst layer at the cathode (i.e., the reaction surface) in a single cell of polymer electrolyte fuel cell (PEFC). A 1D multi-plate heat transfer model based on the temperature data of the separator measured using the thermograph in a power generation experiment was developed to evaluate the reaction surface temperature (Treact). In addition, to validate the proposed heat transfer model, Treact obtained from the model was compared with that from the 3D numerical simulation using CFD software COMSOL Multiphysics which solves the continuity equation, Brinkman equation, Maxwell-Stefan equation, Butler-Volmer equation as well as heat transfer equation. As a result, the temperature gap between the results obtained by 1D heat transfer model and those obtained by 3D numerical simulation is below approximately 0.5 K. The simulation results show the change in the molar concentration of O2 and H2O from the inlet to the outlet is more even with the increase in Tini due to the lower performance of O2 reduction reaction. The change in the current density from the inlet to the outlet is more even with the increase in Tini and the value of current density is smaller with the increase in Tini due to the increase in ohmic over-potential and concentration over-potential. It is revealed that the change in Treact from the inlet to the outlet is more even with the increase in Tini irrespective of heat transfer model. This is because the generated heat from the power generation is lower with the increase in Tini due to the lower performance of O2 reduction reaction.

Research on Hydrodynamics Model Test for Deepsea Open-Framed Remotely Operated Vehicle

This paper presents the features of newly designed hydrodynamics test for the scaled model of 4500 m deepsea open-framed remotely operated vehicle （ROV）, which is being researched and developed by Shanghai Jiao Tong University. Accurate hydrodynamics coefficients measurement and spatial modeling of ROV are significant for the maneuverability and control algorithm. The scaled model of ROV was constructed by 1：1.6. Hydrodynamics coefficients were measured through VPMM and LAHPMM towing test. And dynamics model was derived as a set of equations, describing nonlinear and coupled 5-DOF spatial motions. Rotation control motion was simulated to verify spatial model proposed. Research and application of hydrodynamics coefficients are expected to enable ROV to overcome uncertainty and disturbances of deepsea environment, and accomplish some more challengeable and practical missions.

西门子Operate高级编程的旋转坐标系二次开发

应用西门子Operate的Easyscreen功能,简便而实用地实现了卧式加工中心上经常使用的旋转坐标系的相应机床操作,并详细介绍了其高级编程指令的二次开发的全过程。

Low Gate Voltage Operated Multi-emitter-dot H^+ Ion-Sensitive Gated Lateral Bipolar Junction Transistor

A low gate voltage operated multi-emitter-dot gated lateral bipolar junction transistor （BJT） ion sensor is proposed. The proposed device is composed of an arrayed gated lateral BJT, which is driven in the metal-oxidesemiconductor field-effect transistor （MOSFET）-BJT hybrid operation mode. Further, it has multiple emitter dots linked to each other in parallel to improve ionic sensitivity. Using hydrogen ionic solutions as reference solutions, we conduct experiments in which we compare the sensitivity and threshold voltage of the multi-emitter-dot gated lateral BJT with that of the single-emitter-dot gated lateral BJT. The multi-emitter-dot gated lateral BJT not only shows increased sensitivity but, more importantly, the proposed device can be operated under very low gate voltage, whereas the conventional ion-sensitive field-effect transistors cannot. This special characteristic is significant for low power devices and for function devices in which the provision of a gate voltage is difficult.

Analysis of the Self-Protection Characteristics of a 1.5T Bitter-Like HTS Magnet Operated at 65K

We present a conceptual configuration of a high-temperature superconducting（HTS）magnet made from REBCO（Re=Rare Earth,B=Barium,C=Copper,O=Oxide）annular plates,called a Bitter-like HTS magnet,which can operate in persistent current mode without joint resistance and can be excited by a flux pump and without current leads and a persistent power supply.An REBCO annular magnet which can generate 1.5 T corresponding to the operating current density 80%of critical current density of the magnet at an operating temperature of65 K is conceptually designed.Then the thermal stability of the magnet is numerically simulated by Comsol software.Whein a piece of RBCO annular plate quenches,the maximum released energy is its stored energy because each REBCO annular plate in the Bitter-like magnet is in parallel.To calculate the stored energy in the REBCO annular plate,the inductance of every annular plate,including self-inductance and mutual inductance,is calculated.Compared with the minimum quench energy（MQE）and stored energy in one REBCO annular plate,the stored energy in one REBCO annular plate is always smaller than the MQE,and the REBCO annular plate will not be damaged even though the stored energy in the REBCO annular plate is fully released,which indicates that this 1.5 T Bitter-like magnet has the property of self-protection.

United Actions:China and Europe Cooperate to Fight COVID-19

“A range of measures have been taken to fight COVID-19 in Germany.The diagnosis and treatment programs that have been adopted include a combination of traditional Chinese medicine(TCM)and Western medicine,which is expected to help the frontline medical staff give better treatment to patients,”said Christoph Gutenbrunner,director of the Rehabilitation Center of Hannover Medical School(MHH)in Germany,at the International Symposium on COVID-19 Treatment(Webcast)held on April 6 with experts from China,U.S.,and Europe,during which they shared their clinical experiences.Gutenbrunner also pointed out that it is essential for the global community to strengthen cooperation and learn from each other’s clinical treatment experience.

THRIVING INDIVIDUALLY-OPERATED ECONOMIC SECTOR

Over the past two years, the individually-operated economic sector in Shandong Province has made rapid development. By the end of 1993, the number of individual households engaged in industrial and commercial undertakings in the province had reached 1.584, involving 3.138 million selfemployed workers, making it the first in the country. The number of licensee

Co-operate with USSR in planning China's first coal-water-fuel pipeline

The Ministry of Energy is co-operating with the Soviet Union in planningChina’s first pipeline to transport coal-water-fuel (CWF).The proposedpipeline,135 km in distance,will run from coal-producing BingxianCounty to Weihe Power Plant In Shaanxi Province.The project is designedto transport 2.5 million Ions of coal slurry annually.Currently Chinese and Soviet experts have finished pre-feasibility studieson the 219 million yuan ( 61.7 million) project and these are about to

Operate界面下STEP7的安装配置方法

介绍Operate界面下如何引导STEP7实现监控的方法。

Domestic Trade Successfully Operated By A Foreign-Trade Enterprise

Ahub of commerce in SouthwesternChina, Chengdu in Sichuan Provinceis well known for its thriving and welldeveloped commerce and trade, with rowupon row of modern shopping centers andbazaars scattered along various specializedbusiness streets. One can imagine how fierceis the competition behind the scenes of thebustle and boom of business! Downtown, anarea known as the Manhattan of Chengdu, anewly built commercial building is growingup, becoming one of the five biggest shoppingcenters in the city; it is the Chengdu ForeignTrade building which opened to businessonly a year ago.

Epidemiological, Clinical and Radiological Study of Patients Operated on for Spondylolisthesis in the Neurosurgery Department of CH “the Luxembourg” in Bamako

Introduction: Spondylolisthesis is defined as a permanent anterior sliding of the vertebral body accompanied by the pedicles, the transverse processes and the posterior joints in relation to the underlying vertebra. The prevalence of spondylolisthesis varies between 4% and 9%, according to different authors in France, China and Japan. In Africa, some African authors find a spondylolisthesis rate of 9.93%. The objective of this study was to study the clinical and radiological aspects of spondylolisthesis at the Mother-Child Hospital of Bamako. Methods: Prospective and retrospective descriptive study carried out in the neurosurgery department of CH Mother-Child Luxembourg in Bamako from 2010 to 2018. Result: We collected 42 patients operated on for spondylolisthesis out of 145 patients, i.e., 29% of the department’s activities. The average age of our patients was 51 years old, with extremes of 20 and 75 years old. The sex ratio was 0.81 in favor of women. 61.9% of our patients performed work requiring physical strength. Neurogenic claudication was the predominant clinical sign with 88.1% of cases. CT was the most common way of exploration in 57.1% of cases and CT myelo in 47.6% of cases. Disc herniation was associated with spondylolisthesis in 23% of cases. Spondylolisthesis was grade 1 in 59.6% of cases and was responsible for mixed stenosis in 73.82% of cases. All our patients underwent laminectomy. The evolution at 6 months postoperative was favorable in 64.3% of cases. Conclusion: The diagnosis of spondylolisthesis is radiological and makes it possible to define the type of lesion according to its etiology and its severity, but also to highlight the conflicts with the nervous system which will have to be cured. Field and household work, pregnancy, carrying loads or children on the back could be incriminated.

Should State-Owned Enterprises Operate Self-Run Kindergartens?

With the arrival of the ＂two child era＂ in China, preschool educa tion has become an even more difficult issue for many Chineseparents. According to the research result of Education Policy Center of Southwest University, with China＇s implementation of the two child policy in 2016, the demand for preschool education will see a sharp increase from 2019 and reach its peak in 2021.

VeneSat-1 Operates Well

VeneSat-1 has operated two years up until now.The spacecraft performs well, according to the Ministry of Science and Technology and the Bolivarian Agency for Space Activities (ABEA) of Venezuela in the late of 2010.

Operating in Tandem Chinese experts in Sao Tome and Principe cooperate with local farmers to raise medical standards in the breeding industry

Santomean pig farmer Simao Vicente was hopeful when he came to ask Zou Rui for help. His pig was suffering from hernia, and Zou, a 42-year-old Chinese agricultural expert working in Sao Tomé and Príncipe, was the only person on the island who could provide emergency surgery.

Impact of Thickness of Polymer Electrolyte Membrane and Gas Diffusion Layer on Temperature Distributions in Polymer Electrolyte Fuel Cell Operated at Temperature around 90℃

Polymer Electrolyte Fuel Cell(PEFC)is desired to be operated at temperature around 90℃ for stationary applications during the period from 2020 to 2025 in Japan.It can be expected thinner polymer electrolyte membrane(PEM)and gas diffusion layer(GDL)would promote the power generation performance of PEFC at this temperature.The aim of this study is to understand the impact of thickness of PEM and GDL on the temperature profile of interface between PEM and catalyst layer at the cathode(i.e.,the reaction surface)in a single PEFC with an initial operation temperature(Tini).An 1D multi-plate heat transfer model based on temperature data of separator measured using thermograph in power generation process was developed to evaluate temperature of the reaction surface(Treact).This study investigated the effect of Tini,flow rate and relative humidity of supply gas on Treact distribution.The study finds that when using thin GDL,the even distribution of Treact – Tini is obtained irrespective of thickness of PEM,Tini and relative humidity conditions.Treact – Tini using Nafion 115 is higher than the other thin PEMs irrespective of Tini and relative humidity conditions.It can be concluded that the even temperature distribution could be achieved by using thin PEM and GDL.

A real-world data collection framework for a fused dataset creation for joint human and remotely operated vehicle monitoring and anomalous command detection

Unmanned Remotely Operated Vehicles(ROVs)are widely used in safety-critical missions,spanning across monitoring,surveillance,and search and rescue missions.In most cases,the human operator controls the ROV under stressful conditions and in harsh environments.The physical and mental states of the operator are vital as they may cause involuntary movements,issuing unintentional commands due to fatigue or stress.Consequently,a joint monitoring mechanism that will assess the operator's commands can be beneficial in preventing potentially catastrophic events,such as accidents.To this end,in this study,we propose a data collection framework for creating a fused dataset,consisting of data obtained from both the human operator and the ROV,and we integrate stress induction to stimulate stress and fatigue that may affect operators during missions.We optimise the dataset,which includes the operator's physiological signals and inertial measurement unit(IMU)sensor data from the ROV,using data fusion approaches and feature extraction.We evaluate the dataset through the statistical analysis,illustrating a statistical difference between data characterising normal and involuntary commands.Finally,we evaluate the optimised and original datasets over a variety of classifiers,demonstrating an accuracy of 94%and 95%,respectively.