基于PID算法的磁场闭环控制技术研究

已有的束流磁场控制方法大多采用开环的方式,即根据磁场需求直接设置磁铁电源输出的电流或电压值.但开环状态的磁场在现场噪声以及磁铁自身涡流效应的影响下,极容易发生偏移.针对此问题,设计了基于PID算法的磁场闭环控制系统.该系统以偏转磁铁为控制对象,使用霍尔传感器获取磁场值作为反馈,磁铁电源励磁电流的输出作为控制系统的输入量...     

细胞松弛素B阻断微核法鉴定男性个体辐射敏感性的方法初探

初步研究了男性个体辐射敏感性的鉴定方法及标准.采集50名男性志愿者的外周血,分别给予不同剂量X射线照射,采用细胞松弛素B阻断双核法测定微核率(MNF),通过二阶多项拟合法,绘制微核剂量效应选项中心标准曲线,将个人微核剂量效应曲线与标准曲线比对后判断个体辐射敏感性.0.0～2.5 Gy剂量范围内,剂量效应二阶多项拟合的中...     

TiO2 Nanotube Array/Monolayer Graphene Film Schottky Junction Ultraviolet Light Photodetectors

Schottky junctions made from a titanium dioxide nanotube (TiO₂NT) array in contact with a monolayer graphene (MLG) film are fabricated and utilized for UV light detection. The TiO₂NT array is synthesized by the anodization and the MLG through a simple chemical vapor deposition process. Photoconductive analysis shows that the fabricated Schottky junction photodetector (PD) is sensitive to UV light illumination with good stability and reproducibility. The corresponding responsivity (R), photoconductive gain (G), and detectivity (D*) are calculated to be 15 A W^?1, 51, and 1.5 × 10¹² cm Hz^1/2 W^?1, respectively. It is observed that the fabricated PD exhibits spectral sensitivity and a simple power‐law dependence on light intensity. Moreover, the height of the Schottky junction diode is derived to be 0.59 V by using a low temperature I–V measurement. Finally, the working mechanism of the TiO₂NT array/MLG film Schottky junction PD is elucidated.     

Preparation and characterization of vinyltriethoxysilane based inorganic–organic gel glasses dispersed 4′-n-pentyl-4-cyanobiphenyl nematic liquid crystal

Vinyltriethoxysilane based inorganic–organic glasses dispersed with 4′-n-pentyl-4-cyanobiphenyl nematic liquid crystal are designed to fabricate a new type of gel glass dispersed with liquid crystal. Scanning electron microscopy shows that the nematic liquid crystal phase, occupying the interconnected cavities, is continuously embedded in the inorganic–organic matrixes. The effect of the nematic liquid crystal weight concentration on the morphology is investigated. The differential scanning calorimetry shows that the nematic-isotropic transition temperature depends on the nematic liquid crystal weight concentration. The Raman spectra show that there are no obvious Raman frequency shifts, compared with pure nematic liquid crystal. The in situ diffuse reflectance FTIR spectra show that the integral intensity of bands of hydroxyls has not varied.     

包钴型γ-Fe2O3磁粉矫顽力的研究

包钴型γ-Fe₂O₃磁粉分为包钴γ-Fe₂O₃(简记为Co-γ-Fe₂O₃)和包钴包亚铁γ-Fe₂O₃(简记为CoFe-γ-Fe₂O₃)两种,它们的矫顽力可比γ-Fe₂O₃磁粉的提高100至400Oe左右,本工作对这两种磁粉矫顽力增大的原因作了探讨,认为它们矫顽力增大的机制不同:CO-γ-Fe₂O₃矫顽力增大是由于表面包覆一层Co(OH)₂使表面各向异性增大,而CoFe-γ-Fe₂O₃则是由于表面包覆的是钴铁氧体,γ-Fe₂O₃与钴铁氧体之间发生耦合作用,使矫顽力增大。     

加权移位算子的拟相似与谱

加权移位算子的拟相似与谱许凤，卢玉峰（东北师范大学数学系，长春１３００２４）１９９１年１２日２４日收到．设Ｈ是复可分Ｈｉｌｂｅｒｔ空间，Ｌ（Ｈ）表示Ｈ上有界线性算子全体，Ｚ是整数全体，Ｚ＋是非负整数全体，Ｉ＝Ｚ或Ｚ是Ｈ的正规正交基，是有界数列，Ｋ是一...     

广义［d，k］－自控序列的周期特性

广义［ｄ，ｋ］－自控序列的周期特性冯克勤（中国科学技术大学数学系，合肥２３００２６）李超（国防科学技术大学数学系，长沙４１０００３）ＰＥＲＩＯＤＩＣＰＲＯＰＥＲＴＩＥＳＯＦＴＨＥＧＥＮＥＲＡＬＩＺＥＤ［ｄ，ｋ］－ＳＥＬＦＣＯＮＴＲＯＬＬＥＤＳＥＱＵＥ...     

用形状指数研究苯酚类化合物对大型蚤的急性毒性

基于分子拓扑理论，计算了18种取代苯酚的Kier分子形状拓扑指数（^mK）．利用最小二乘法建立了不同pH值下11种取代苯酚对大型蚤急性毒性（pIC50）的QSAR模型，其相关系数（R^2）依次为：0．963（pH=6．0），0．966（pH=7．8），0.846（pH=9．0）．这些模型的计算值与其实验值基本吻合．通过留一法检验及对其余7种取代苯酚类化合物的pIC50值进行预测，结果表明该模型具有良好的稳健性和预测能力．     

反应条件对水热合成二硫化镍NiS2粉晶的影响

本文采用水热法一步合成了二硫化镍粉晶,利用X射线衍射(XRD),扫描电子显微镜讨论了样品N iS2粉晶的晶体结构及形貌,研究了X射线衍射峰积分强度以及半峰宽等随反应条件的变化,并分析了N iS2粉晶的合成机理.