火焰侦测器的设计以及与特气系统的联动

介绍了基于火焰侦测器和特气系统联动的内容,以保障工业生产安全。首先,我们对火焰侦测器的原理和类型进行了介绍,并对其进行了选择和优化。其次,我们将火焰侦测器与特气系统进行了联动分析,通过GC和VMB中的火焰探测器以及其中的PLC控制模块的分析及信号输出,实现了火焰侦测器的实时监测和特气系统的自动化控制,有效避免了火灾事故的发生。

小规模6英寸晶圆厂特气系统的维护与质量控制

文章介绍了6英寸小规模科研生产线特气系统的系统组成,对日常特气系统的维护进行了分析与阐述,同时对特气系统的质量控制做了简要的分析。

关于半导体、平板显示行业特气系统构筑的要点分析

集成电路芯片、平板显示制造广泛使用特殊气体,制造过程中对特气系统安全、供应稳定性要求极高。目前特气系统设计可参照的国际标准规范有:SEMI、NFPA、CGA、FM[1],国内标准有:《特种气体系统工程技术标准-GB60646》,这些文献重点阐述特气系统的安全总体要求,且集成电路、平板显示(TFT-LCD、AMOLED)这些细分领域特气使用特征还存在较大差异,为解决工厂建设者在特气系统构筑的整个过程中缺少参考文献的问题,作者结合作者多年建设和运行的经验,从建设方安全稳定运行的角度出发提出设计中需要关注且容易忽略的一些细节问题,以期为半导体、平板显示等电子工厂特气系统的设计和建设人员提供参考。

浅析半导体晶圆代工厂的特气供应系统

本文先从特种气体在半导体晶圆代工厂的应用及气体的不同特性进行了分类和讨论,进而对特种气体在晶圆厂的主要供应流程及其要点进行了较具体阐述,并且对在晶圆厂有着重要作用的关键管件及设计要点进行了探讨,以便读者对整个特种气体供应系统在晶圆代工厂的储存、输送与控制等有较为清楚的了解。

Climate Characteristics of Thunder and Lightning in Anyang City

The research explored frequencies of different weathers caused by con-vection, characters of thunder and lightning, spatial and temporal changes, move-ment routes, geographical distribution, daily, monthly and annual changes of thunder or lightning, based on 30 years information. Furthermore, a search system of thun-derstorm in history was established, laying foundation for prevention and prepared-ness of thunderstorm in Anyang.

Micromixing characteristics in a gas-liquid-solid stirred tank with settling particles

The parallel-competing iodide-iodate reaction scheme was used to study the micromixing performance in a multi-phase stirred tank of 0.3 m diameter.The impeller combination consisted of a half elliptical blade disk turbine below two down-pimping wide-blade hydrofoils,identified as HEDT + 2WH_D.Nitrogen and glass beads of100 μm diameter and density 2500 kg-m^(-3) were used as the dispersed phases.The micromixing could be improved by sparging gas because of its additional potential energy.Also,micromixing could be improved by the solid particles with high kinetic energy near the impeller tip.In a gas-solid-liquid system,the gas-liquid film vibration with damping,due to the frequent collisions between the bubbles and particles,led to the decrease of the turbulence level in the liquid and caused eventually the deterioration of the micromixing.A Damping Film Dissipation model is formulated to shed light on the above micromixing performances.At last,the micromixing time t_m according to the incorporation model varied from 1.9 ms to 6.7 ms in our experiments.

Airflow characteristics by air curtain jets in full-scale room

A new air distribution pattern,air curtain jet ventilation was presented.The ventilation or airflow patterns and the air velocity produced by air curtain jet were investigated in detail.To identify the airflow characteristics of this novel air curtain jet ventilation system,a full-scale room was used to measure the jet velocity with a slot-ventilated supply device,with regards to the airflow fields along the vertical wall as well as on the horizontal floor zones.The airflow fields under three supply air velocities,1.0,1.5 and 2.0 m/s,were carried out in the full-scale room.The experimental results show the velocity profiles of air distribution,the airflow fields along the attached vertical wall and the air lake zones on the floor,respectively.The current experimental research is helpful for heating,ventilation and air conditioning(HVAC) engineers to design better air distribution in rooms.

Effects of wind barriers on the aerodynamic characteristics of bridge-train system for a road-rail same-story truss bridge

Wind barriers are commonly adopted to prevent the effects of wind on high-speed railway trains,but their wind-proofing effects are greatly affected by substructures.To investigate the effects of wind barriers on the aerodynamic characteristic of road-rail same-story truss bridge-train systems,wind tunnel experiments were carried out using a 1:50 scale model.Taking a wind barrier with a porosity of 30%as an example,the aerodynamic characteristics of the bridge train system under different wind barrier layouts(single-sided and double-sided),positions(inside and outside)and heights(2.5 m,3.0 m,3.5 m and 4.0 m)were tested.The results indicate that the downstream inside wind barrier has almost no effect on the aerodynamic characteristics of the train-bridge system,but the downstream outside wind barrier increases the drag coefficient of the bridge and reduces both the lift coefficient and drag coefficient of the train due to its effect on the trains wind pressure distribution,especially on the trains leeward surface.When the wind barriers are arranged on the outside,their effects on the drag coefficient of the bridge and shielding effect on the train are greater than when they are arranged on the inside.As the height of the wind barrier increases,the drag coefficient of the bridge also gradually increases,and the lift coefficient and drag coefficient of the train gradually decrease,but the degree of variation of the aerodynamic coefficient with the height is slightly different due to the different wind barrier layouts.When 3.0 m high double-sided wind barriers are arranged on the outside of the truss bridge,the drag coefficient of the bridge only increases by 12%,while the drag coefficient of the train decreases by 55%.

Research on fault mode and diagnosis of methane sensor

To improve the reliability of coal mine safety monitoring systems we have analyzed the characteristics of a methane sensor, an important component of the monitoring system of production safety in a coal mine and studied the main type and mode of faults when the sensor was used on-line. We introduced a new method based on artificial neural network to detect faults of methane sensors. In addition, using the output information of a single methane sensor, we established a sensor output model of a dynamic non-linear neural network for on-line fault detection. Finally, the fault of the heating wire of the sensor was simulated, indicating that, when the methane sensor had a fault, the predicted output of the neural network clearly deviated from the actual output, exceeding the pre-set threshold and showing that a fault had occurred in the methane sensor. The result shows that the model has good convergence and stability, and is quite capable of meeting the requirements for on-line fault detection of methane sensors.

Observed characteristics of atmospheric ducts over the South China Sea in autumn

The observed characteristics of lower atmospheric ducts over the South China Sea(SCS) were analyzed based on Global Position Systerm(GPS) radiosonde data collected four times daily during autumn open cruises from 2006 to 2012.Duct occurrence,thickness,and strength over the SCS were about 40%,150-m thick,and 8 M units,respectively,which were larger than during the summer monsoon period.Most ducts occurred at heights <1 500 m and these ducts easily trap electromagnetic wave clusters with wavelengths <2 m.Diurnal variation of the SCS ducts appeared evident.They occurred more often at midnight at higher altitudes(about 1 100 m),with a thickest layer of about 145 m and less frequently during the evening at lower altitudes(about 800 m),with a thinnest layer of about 125 m.Moreover,ducts during the daytime at a mean height of about 900 m,with the greatest strength of about 10 M units.Furthermore,all duct variables observed over the SCS in autumn decreased from north to south.These findings are useful not only in the design of radar and communication systems,but also for evaluating possible effects of anomalous propagation on meteorological radar and military applications.

Family history of cancer in Chinese gastric cancer patients

Objective:The aim of the study was to investigate the influence of gastric cancer family history in the gastric cancer (GC) patients. Methods: Gastric cancer family histories within second degree relatives and clinicopathological features were obtained for 497 patients. Results:Of the 497 probands,235 probands were incorporated into familial gastric cancer (FGC) group (there were at least two GC members in the family); 262 probands were included in the non-FGC group (relatives only affected with non-GCs). Of 614 tumors in relatives,GC was the most frequent,followed by lung cancer,esophageal cancer,hepatocellular cancer,colorectal cancer,urogenital cancer,breast cancer,and pancreatic cancer. Most affected members aggregated within first-degree relatives. The ratio of males to females in affected first-degree relatives was usually higher in male probands. Paternal history of GC was a strong risk for GC in males,while risk of GC by maternal history of GCs was increased in females. Difference in tumor histological types between the two groups was derived from an excess of diffuse GC in non-FGC male probands. The lower site was the most frequent tumor location in all subgroups. Conclusion:Distribution of associated non-GCs in a family history of GC may vary with geographic areas. GC may have different genetic and/or environmental etiology in different families,and a certain subtype may be inherited in a male-influenced fashion.

Responses of River Runoff to Climate Change Based on Nonlinear Mixed Regression Model in Chaohe River Basin of Hebei Province, China

Taking the nonlinear nature of runoff system into account,and combining auto-regression method and multi-regression method,a Nonlinear Mixed Regression Model (NMR) was established to analyze the impact of temperature and precipitation changes on annual river runoff process. The model was calibrated and verified by using BP neural network with observed meteorological and runoff data from Daiying Hydrological Station in the Chaohe River of Hebei Province in 1956–2000. Compared with auto-regression model,linear multi-regression model and linear mixed regression model,NMR can improve forecasting precision remarkably. Therefore,the simulation of climate change scenarios was carried out by NMR. The results show that the nonlinear mixed regression model can simulate annual river runoff well.

DC Characteristics of Lattice-Matched InAlN/AlN/GaN High Electron Mobility Transistors

Lattice-matched InAlN/AlN/GaN high electron mobility transistors (HEMTs) grown on sapphire substrate by using low-pressure metallorganic chemical vapor deposition were prepared, and the comprehensive DC characteristics were implemented by Keithley 4200 Semiconductor Characterization System. The experimental results indicated that a maximum drain current over 400 mA/mm and a peak external transconductance of 215 mS/mm can be achieved in the initial HEMTs. However, after the devices endured a 10-h thermal aging in furnace under nitrogen condition at 300 ℃, the maximum reduction of saturation drain current and external transconductance at high gate-source voltage and drain-source voltage were 30% and 35%, respectively. Additionally, an increased drain-source leakage current was observed at three-terminal off-state. It was inferred that the degradation was mainly related to electron-trapping defects in the InAlN barrier layer.

Assessment of occupational noise pollution for metal industries in Kingdom of Saudi Arabia

The main objectives of this study was measuring levels of noise generated by machinery that workers at metal industrial facilities in the Kingdom of Saudi Arabia （KSA） are exposed to as well as to determine if these levels were in conformity with adopted standards. To achieve the objectives of this study the following six metal industrial facilities were selected： a foundry plant, a building-metal production factory, a cold processing steel manufacturing plant, a hollow-metal door and doorframe manufacturer, a car-exhaust-system factory and a metal-can producer. The study found that workers operating machinery without any kind of protection were exposed to unacceptably high levels of noise that exceeded the internationally acceptable values as per occupational noise exposure-1910.95 regulations adopted standard. It was founded that 73% of work site investigated have noise level over 85 dB. A level of 116 dB was recorded at steel plant fiat section product with continuous occupation and 115.2 dB in metal product factory with labor continuous occupation. Based on the results obtained in this study, it is evident that a competent environmental and health agency needs to be established and that stricter noise-level standards ought to be enforced in order to protect employee health.

Study on air flow dynamic characteristic of mechanical ventilation of a lung simulator

As an important life support treatment, mechanical ventilation is usually adopted in clinics. With the development of the res-piratory diagnostic and treatment technologies, air flow dynamics of mechanical ventilation is usually referenced in the evaluation of pulmonary status and assessment of respiratory therapy. In order to improve the ventilation efficiency and provide a reference for pulmonary diagnostics, in this paper, a new mathematical model of mechanical ventilation system was set up. Furthermore, a prototype mechanical ventilation system for an artificial simulating lung was designed and experimentally studied. Lastly, in order to improve the ventilation efficiency and provide a reference for pulmonary diagnostics, the air flow dynamics of the mechanical ventilation system was illustrated through simulation and experimental studies. The study can be helpful to the optimization of the mechanical ventilation system.

Dynamics of a deflectable-nose missile

The dynamics of a supersonic missile with a deflectable nose are studied. To describe the effects of nose deflection on the dynamic model, theorems of momentum and angular momentum are adopted to develop the translational equation and rotation equation, respectively. Because the exact model is complex, it is simplified. The simplified model suggests that the main influence of nose deflection on the dynamic model is due to the product of the time derivatives of the azimuth angle and the elevation angle, which makes the dynamic model an impulsive differential system. Considering the aerodynamic characteristics a numerical simulation is sufficient to show the open-loop characteristics of the missile.

Analysis of spatio-temporal features of a carbon source/sink and its relationship to climatic factors in the Inner Mongolia grassland ecosystem

Global climate change has become a major concern worldwide. The spatio-temporal characteristics of net ecosystem productivity(NEP), which represents carbon sequestration capacity and directly describes the qualitative and quantitative characteristics of carbon sources/sinks(C sources/sinks), are crucial for increasing C sinks and reducing C sources. In this study, field sampling data, remote sensing data, and ground meteorological observation data were used to estimate the net primary productivity(NPP) in the Inner Mongolia grassland ecosystem(IMGE) from 2001 to 2012 using a light use efficiency model. The spatio-temporal distribution of the NEP in the IMGE was then determined by estimating the NPP and soil respiration from 2001 to 2012. This research also investigated the response of the NPP and NEP to the main climatic variables at the spatial and temporal scales from 2001 to 2012. The results showed that most of the grassland area in Inner Mongolia has functioned as a C sink since 2001 and that the annual carbon sequestration rate amounts to 0.046 Pg C/a. The total net C sink of the IMGE over the 12-year research period reached 0.557 Pg C. The carbon sink area accounted for 60.28% of the total grassland area and the sequestered 0.692 Pg C, whereas the C source area accounted for 39.72% of the total grassland area and released 0.135 Pg C. The NPP and NEP of the IMGE were more significantly correlated with precipitation than with temperature, showing great potential for C sequestration.