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941.
取稀土工业园区的污水处理设施和受影响河流的的污泥样品,分别采用三种样品预处理方法(敞开式酸溶法、石墨加热消解和微波消解法)进行对比研究,结果表明:石墨消解法前处理污泥样品后,使用ICP-MS测定其中稀土元素(Y、La、Ce、Pr、Nd、Sm、Eu、Gd、Tb、Dy、Ho、Er、Tm、Yb、Lu),其方法简便快捷,检出限低,准确度好。 相似文献
942.
Elena Filatova Aleksei Konashuk Yuri Petrov Evgeny Ubyivovk Andrey Sokolov Andrei Selivanov 《Science and Technology of Advanced Materials》2016,17(1):274-284
We have studied the stability of the resistive switching process in the Al/(In2O3)0.9(SnO2)0.1/TiO2 assembly grown by atomic layer deposition. Besides electrical characterization the effect of electric field on the atomic electronic structure of the TiO2 layer was studied using near edge X-ray absorption fine structure (NEXAFS) spectroscopy. The region of the current instability in the I-V characteristics was revealed. Presumably this current instability is supported by the amorphous structure of the TiO2 film but is initiated by the surface morphology of the Al substrate. A formation of the O2 molecules was established which occurs specifically in the region of the current instability that is a result of electrical Joule heating manifestation. 相似文献
943.
Qilong Wang Cairu Yu Yusong Di Zhuoya Zhu Xiaobing Zhang Chen Li 《Fullerenes, Nanotubes and Carbon Nanostructures》2016,24(4):273-277
High-current-density field emitters are considered as the potential and necessary components for compact high definition x-ray sources and high-power cold cathode microwave amplifiers. In this report, high-current-density field emission from self-heating printed carbon nanotubes is introduced. Large emission current causes large heat that increases the temperature of the emitters. The temperature is estimated to be more than ~1600 K. Localized surface field and high temperature both drive more electrons escaping from the emitters, and the maximum current density is larger than ~2.7 A/cm2 that will satisfy the need of most vacuum electron devices including x-ray sources and microwave electron devices. 相似文献
944.
采用渠道衬砌前后单位长度渗漏损失差值计算工程节水量的方法,对内蒙古包头市黄河灌区实施渠道衬砌后进行计算,灌区总节水量8 310.01万m3,其中镫口灌区节水量4 709.06万m3,民族团结灌区节水量3 600.95万m3。灌区渠系水利用系数由现状的0.58提高到0.749,农田灌溉水利用系数由现状的0.41提高到0.674。该方法旨在为全面实施用水总量控制、提高农田灌溉水有效利用系数提供借鉴。 相似文献
945.
加热段温度控制是立式连续退火炉的核心和关键子系统,针对加热段温度控制大滞后、非线性、多扰动的特点,设计一种串级温度控制系统,它以炉区负荷控制为外环,助燃空气-燃气交叉控制为内环,配合带钢温度纠偏控制、过温控制、调节器参数自适应等辅助手段,提高连退炉温度控制的精度、响应速度以及燃气加热的效率。所述连退炉加热段温度控制方法已在某冷轧厂1850 mm连续退火炉工程上成功应用,并取得良好的控制效果。 相似文献
946.
947.
张峻颖 《计算技术与自动化》2011,30(2):72-74
把近年来工业中广泛应用的动态矩阵控制方法应用于电加热炉为对象的单片机温度控制系统中,该温度控制系统采用MSP430作为CPU,使用DMC作为控制策略完成温度控制,其控制效果与常规的数字PID算法进行比较。结果表明:使用DMC算法的系统响应速度和动态性能明显优于常规数字PID。其控温精度高,鲁棒性强,因此进一步推广该算法... 相似文献
948.
ABSTRACT Parametric analyses of the strain-stress in the drying process are performed to study the influence of the intermittent drying on the behaviors of drying-induced strain-stress and deformation as well as the drying characteristic. The transient three-dimensional problem of strain-stress and heat and moisture transfer in a slab is solved simultaneously by the finite element method. The dimensionless parameters are introduced to generalize the problem in the conservation equations of heat and moisture transfer. The intermittent drying is modeled by applying periodically smaller and larger Biot numbers to the boundary conditions. The maximum tensile and compressive stresses fluctuate, and fall remarkably during the smaller Biot number period when a slab is heated intermittently. The peak stress of the fluctuation exceeds beyond the case in the continuous healing where the overall drying rate is almost equivalent to that in the intermittent beating, but the reduction of the stresses takes place rapidly in the low heating period. 相似文献
949.
ABSTRACT This paper presents an Overview of particulate medium drying and heat treating of cereal grains. While the conventional air drying of grains is well documented, studies on the drying of grains using heated granular medium do not appear to exist. The scientific study of the different aspects of drying with a heated granular medium began in the early 1970's. Progress on the utilization of particle-to-particle heat transfer was slow as evidenced by the fact that there is no commercial dryer using the method as of today. The first section of this paper deals with conduction heating and how it led to the use of granular medium in heating the grain. Starting with the earliest work on conduction heating reported by Kelly ( 1939), the developments in the heating of grain using granular media is discussed. For decades since Kelly's report, work in the subject area dealt mostly with the theoretical aspects of solid-to-solid heat transfer. Thus, in the succeeding section of the paper, heat transfer parameters and mechanisms involved in the process are thoroughly investigated. 相似文献
950.
Unicase炉有效加热区的测定 总被引:1,自引:1,他引:0
本文介绍了Unicase炉有效加热区的测定方法,阐述了空炉测温的必要性,并对测量结果不理想时提出了改进措施。 相似文献