5个中华按蚊种群对溴氰菊酯的抗性及抗性选择反应

经浙江省 5个中华按蚊自然种群和敏感品系对溴氰菊酯抗性测定 ,发现其致死中浓度 ( LC50)都比各自的敏感品系高 ,特别是来自温州的中华按蚊 ,其抗性比率 ( RR50)达 11倍之多 . 将各自然种群的蚊虫进行抗性筛选 12代 ,发现其抗性水平与敏感品系相比 ,高达 130～ 190倍; 与其自然种群相比达 10～40倍 . 来自温州种群的抗性品系的选择性反应 ( R值 )小于 0. 1,而其它抗性品系大于 0. 1,这表明从抗性概率较高的自然种群中筛选的抗性品系 ,其抗性增加速率低于那些从抗性概率较低的自然种群中所筛选的抗性品系 ,即 5个自然种群的抗性潜能应该是相似的 . 最后对相应的蚊虫防治策略进行了讨论 .     

一种新型大鼠抗阻训练模型的建立

目的研究人员已设计出多种大鼠抗阻训练模型并得到较广泛应用,但现有的抗阻训练模型仍存在一些不足。为此,设计了一种新型大鼠抗阻训练模型。方法通过逐步提高放置饲料和饮水的鼠盒盖而达到大鼠自主攀爬运动的目标。结果该模型制作简易、训练过程对动物造成的心理应激小,行为学观察效果良好。结论该大鼠抗阻训练模型建立成功,有望用于抗阻训练的生理适应研究。     

抗耐土壤稳定剂加固细粒土的微观结构分析

为了更好地评价AC101抗耐土壤稳定剂的加固作用,首先对其产品性能和作用机理进行了分析,然后选取山东省济宁地区的细粒土应用AC101进行加固,同时用水泥、石灰两种常规的稳定材料也对其进行加固,再利用TS5136XM型钨灯丝扫描电子显微镜,采集三种固化剂及加固前后土体试样的微观结构照片。通过观测比较,探讨了抗耐土壤稳定剂加固细粒土的作用机理。结果表明,AC101抗耐稳定剂对于快速加固细粒土具有一定的作用。     

白菜耐热性研究综述

本文从白菜耐热性的生理、遗传、品种选育及配套栽培技术等方面对白菜耐热性研究进行归纳总结。     

高稳定度电磁透镜电流源基准电阻的温度补偿

电流源的稳定度是影响高稳定度电磁透镜分辨率与成像质量的关键因素之一,而基准电阻作为电流源的反馈元件,其稳定度直接影响电流源的稳定度。为了提高基准电阻的稳定性,通过分析基准电阻与页温度系数(negative temperature coefficient, NTC)热敏电阻的温度特性,并提出了一种通过NTC热敏电阻对基准电阻进行温度补偿的电路结构。最后以Pt100电阻作为基准电阻,分析了该电路结构的性能。结果表明,与基准电阻相比,经补偿后所得到的等效基准电阻的稳定性提高了10倍以上。     

Promotion effect of Pt on a SnO2–WO3 material for NOx sensing

Metal-oxide nanocomposites were prepared over screen-printed gold electrodes to be used as room-temperature NO_x (nitric-oxide (NO) and nitrogen dioxide (NO₂)) sensors. Various weight ratios of SnO₂–WO₃ and Pt loadings were used for NO sensing. The sensing materials were characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM) and BET surface analysis. The NO-sensing results indicated that SnO₂–WO₃ (1:2) was more effective than other materials were. The sensor response (S=resistance of N₂/resistance of NO=R_N2/R_NO) for detecting 1000 ppm of NO at room temperature was 2.6. The response time (T₉₀) and recovery time (TR₉₀) was 40 s and 86 s, respectively. By further loading with 0.5% Pt, the sensor response increased to 3.3. The response and recovery times of 0.5% Pt/SnO₂–WO₃ (1:2) were 40 s and 206 s, respectively. The linearity of the sensor response for a NO concentration range of 10–1000 ppm was 0.9729. A mechanism involving Pt promotion of the SnO₂–WO₃ heterojunction was proposed for NO adsorption, surface reaction, and adsorbed NO₂ desorption.     

Electric-pulse-induced local conducting area and joule heating effect in VO2/Al2O3 films

We investigated the effect of an electric-pulse on the insulator–metal phase transition of VO₂/Al₂O₃ films using synchrotron-based infrared microspectroscopy. By monitoring the time-resolved optical response, we could demonstrate that local conducting areas are formed under the influence of the electric-pulse, and the Joule heat generated from the local current flow drives a consecutive thermal phase transition in the adjacent sample area.     

GaAs光电阴极片原子级表面清洁方法的研究及评价

本文对GaAs光电阴极片UHV系统中原子级表面清洁方法做了研究,它们是:光加热法、直接加热法、离子轰击加退火法、热子加热法,表面清洁效果用装于UHV系统中间在线俄歇检测,表面质量用Aa/GaAuger峰高进行比较,指出两种用于第三代象增强器光电阴极的表面清洁方法:CS-离子轰击加退火法和热子背加热法。     

Dielectric-breakdown-like forming process in the unipolar resistance switching of Ta2O5−x thin films

We report unipolar resistance switching (URS) in Ta₂O_5−x thin films. The current increased suddenly when we applied voltages up to 5-7 V to the pristine state of Pt/Ta₂O_5−x/Pt, Ni/Ta₂O_5−x/Pt, and Ti/Ta₂O_5−x/Pt cells. Just after this forming process, we observed a repetitive URS occurring independently of the electrodes. We found that the required voltages for the forming process did not depend on the top electrode type, but on the film thickness. These results suggest that the forming process is driven by a dielectric-breakdown-like phenomenon, and that URS occurs due to the formation and rupture of conducting channels inside the Ta₂O_5−x thin film.     

Resistance switching memory in perovskite oxides

The resistance switching behavior has recently attracted great attentions for its application as resistive random access memories (RRAMs) due to a variety of advantages such as simple structure, high-density, high-speed and low-power. As a leading storage media, the transition metal perovskite oxide owns the strong correlation of electrons and the stable crystal structure, which brings out multifunctionality such as ferroelectric, multiferroic, superconductor, and colossal magnetoresistance/electroresistance effect, etc. The existence of rich electronic phases, metal–insulator transition and the nonstoichiometric oxygen in perovskite oxide provides good platforms to insight into the resistive switching mechanisms.