太阳辐照绝对辐射计的精密温度控制系统设计

为了提高太阳辐照绝对辐射计(SIARs)的测量精度,消除温度变化对SIARs测量精度的影响,研究设计了精密温度控制系统,对SIARs进行恒温控制;通过对铂电阻温度传感器自热效应的弱化,提高了温度测量的精度;提出了一种新的复合PID控制算法,该复合控制算法使系统获得良好的动态和稳态性能;使用密闭的高低温箱来模拟星上温度条件对系统进行了实验测试,实验数据表明,系统控制精度在0.1℃以内,可为SIARs工作提供稳定的温度环境。     

自加热非晶锗热电阻MEMS流速传感器的制造与测试

为扩大流速传感器的测量范围并降低功耗,制造并测试了一种基于自加热非晶锗薄膜热电阻的MEMS流速传感器,它是由嵌入氮化硅薄膜的四个非晶锗热敏电阻和一对环境测温补偿电阻组成。四个非晶锗热电阻同时作为自加热热源和测温元件,相互连接以形成惠斯通电桥。给出了MEMS工艺流程,微加工制造了尺寸为8.9 mm×5.6 mm×0.4 mm的流速传感器芯片。搭建了低流速和高流速气流通道实验装置,对传感器的惠斯通电桥施加50μA的恒定电流(CCA),实现了0～50 m/s范围内的流速测量。结果表明,传感器在低流速(0～2 m/s)时的灵敏度约为81.6 mV/(m/s),在高流速(2～50 m/s)时的灵敏度约为51.9 mV/(m/s),最大功耗仅约为1.03 mW。     

基于积分宽度法测量发光二极管结温方法的研究

本文提出了一种基于光谱积分宽度法来测量发光二极管(light emitting diode, LED)结温的新方法,并进行了理论分析和实验研究。本方法主要分为光谱数据采集、定标函数的测定和结温测量三个过程。首先,为了测量成本的降低和精度的提高而采用在正常工作电流下采集LED光谱数据,并通过采用不同温度下的光谱积分宽度与选定的某一基准状态下的值逐差可得到线性度达0.99以上的定标函数,并通过此定标函数可实时测定任意状态下的结温。其次,为了比较本方法测量结温的精确性,分别对单色和白光LED采用本方法和业界主流的正向电压法,通过自行设计的基于积分宽度法结温测量系统和美国Mentor Graphics公司的T3Ster型仪器的测量结果进行比较,两种方法测出的结温最大偏差为2.1℃,在可接受的误差范围内。实验结果表明积分宽度法测结温具有高效便捷且低成本的的特点,具有一定的应用前景。     

Optimized power simulation of AlGaN/GaN HEMT for continuous wave and pulse applications

An optimized modeling method of 8 × 100 μm AlGaN/GaN-based high electron mobility transistor (HEMT) for accurate continuous wave (CW) and pulsed power simulations is proposed. Since the self-heating effect can occur during the continuous operation, the power gain from the continuous operation significantly decreases when compared to a pulsed power operation. This paper extracts power performances of different device models from different quiescent biases of pulsed current-voltage (I-V) measurements and compared them in order to determine the most suitable device model for CW and pulse RF microwave power amplifier design. The simulated output power and gain results of the models at V_gs = -3.5 V, V_ds = 30 V with a frequency of 9.6 GHz are presented.     

铂电阻温度传感器的自热效应

提出了一种测量铂电阻温度传感器的散热系数的简便方法。测量了不同条件下铂电阻温度传感器的散热系数,并对电阻的自热效应影响进行了探讨。     

Space and time resolved surface temperature distributions in Si power diodes operating under self-heating conditions

In order to optimize and improve the design of power devices with improved surge current safe operating area it is necessary to obtain a good correlation between measured and simulated space and time resolved temperature distributions. Therefore, an IR microscope capable of measuring the space and time resolved surface temperature distributions in Si power diodes operating under self-heating conditions has been developed. The minimum detectable spot size is 15 μm, while the signal rise time is detector limited to about 1 μs. The lower temperature detectivity limit is about 10°C over room temperature.

Using this instrument dynamic thermal phenomena in fast recovery 3.3 kV Si power diodes having radiation-induced recombination centers [Proceedings of the 7th EPE, Trondheim, 1997] subjected to 1.2 ms 400–2000 A/cm² and 0.3–2 ms 2000 A/cm² current pulses have been studied. The experimental results have been compared to results from 2D device simulations including surface recombination and carrier lifetime temperature dependence. The agreement between experimental and device simulation results (i.e. dynamic IV characteristics and time and space resolved temperature distributions) is very good up to a peak current density of 1500 A/cm², and a reasonable good one for peak current densities up to 2000 A/cm² (1.2 ms current pulses).     

红合金浸出试验及设备

本文简要介绍红合金在稀硫酸介质中氧化浸出及使用微泡中和槽作浸出设备的中试效果.     

Estimating activation energy from a sulfide self-heating test

Using a custom-designed self-heating apparatus and procedure, activation energy (E_a) was determined for four sulfide-bearing materials: two nickel concentrates, a copper concentrate and a sphalerite/pyrite mixture. The E_a ranged from 22-29 kJ mol⁻¹, implying a common reaction. Comparing to literature, the E_a values correspond to partial oxidation of hydrogen sulfide, supporting the contention that H₂S may be an intermediate product in the self-heating of sulfide minerals.     

铜自热熔炼炉余热锅炉“汽化冷却器”的应用

阐述了铜自热熔炼炉余热锅炉的结构形式 ,结构特点及试运行的情况。根据运行中出现的问题提出了解决方案。     

水分对孟巴矿煤氧化自燃特性影响的实验研究

采用程序升温实验对孟巴矿不同含水量煤样的自燃特性进行实验研究,通过对不同含水量煤样在程序升温氧化过程中,不同温度条件下的气体产生率、放热强度及耗氧速率分析,得出了孟巴煤矿煤样在氧化自燃过程中,含水量对其氧化自燃性的影响规律,确定出了孟巴矿煤样氧化自燃性最佳的临界水分含量,为孟巴矿煤层自然发火的有效预防提供了基础数据与理论支持。