白光和红绿蓝光LED可调光源研制

为了提高LED光源色温和亮度的调节精度和准确度,结合色温由低向高变化时光色所呈现的渐变特点,提出了一种低色温白光LED灯珠、高色温白光LED灯珠加红绿蓝光LED灯珠补偿式调光的方法.将色温分成三个部分进行调节,每个部分选用不同的LED灯珠组合来进行调光.实验结果表明:不同组合情况下的LED光源的初始输出色温相对于目标值的偏差范围在1％以内;亮度可以在保证色温不变的情况下独立进行调节,初始输出值与目标值的偏差范围在1％以内;经过微调之后可以达到目标值;达到了色温和亮度独立调节的要求;光源发光稳定,不会因为长时间工作而影响调节精度.     

重离子治癌终端的束流强度及剂量监测系统

 为实现重离子肿瘤治疗临床实验中对照射束流状态的实时监测,研制了束流强度及剂量监测系统,包括积分电离室、后续电流频率转换电路及LabVIEW数据获取处理三部分。利用闪烁体探测器和标准剂量计测试了系统的线性响应和得到剂量的准确性,结果表明：系统在束流临床照射流强范围内的线性响应好于90%,其实时反馈的临床照射剂量偏差小于5%。同时束流强度及剂量监测系统与安全控制系统相结合,保证束流照射状态满足临床照射的安全要求。     

基于DRS4测试板的数字波形分析方法（英文）

使用不同的方法来确定La Br3晶体信号的到达时间。在文中信号经过光电倍增管的放大之后由DSR4测试板进行数字采集,其中DRS4是由瑞士PSI研究所生产的高带宽、低功耗以及快读出时间的开关电容阵列。这些优势使得DRS4很具有吸引力,很多实验将传统的ADC与TDC替换为DRS4。采集的波形可以通过不同的方法进行后续处理。其中包括:(1)恒分甄别、(2)波形拟合、(3)PMT脉冲模型法以及(4)均值过滤法。文中实现的恒分甄别的时间分辨与使用模拟电路获取的平均时间分辨相比没有提高。高斯波形拟合法虽然与数字CFD的结果相当,但是却更加耗时。均值滤波法虽然容易实现,但是通过这个方法得到的时间分辨与采样时间在一个量级。而PMT脉冲模型法得到的平均时间分辨为195.4 ps,优于模拟信号的恒分甄别的时间分辨254.7 ps。     

Superparamagnetic nanoparticle-supported catalysis of Suzuki cross-coupling reactions

Emulsion polymerization was examined as a novel route for the synthesis of core/shell superparamagnetic nanoparticles consisting of a highly crystalline gamma-Fe2O3 core and a very thin polymeric shell wall. These nanoparticles were used as soluble supports for immobilizing Pd catalysts to promote Suzuki cross-coupling reactions. Recovery of catalysts was facilely achieved by applying a permanent magnet externally. Isolated catalysts were reused for new rounds of reactions without significant loss of their catalytic activity.     

Preparation of Lignin Carbon/Zinc Oxide Electrode Material and Its Application in Supercapacitors

In this paper, carbon/zinc oxide (LC/ZnO) composites were successfully synthesized and characterized by X-ray powder diffraction, field emission scanning electron microscopy, Fourier transform infrared spectroscopy, Raman, thermogravimetry, and N₂ adsorption–desorption, and tested by electrochemical performance. Studies have shown that the morphology of LC/ZnO composites is that lignin pellets are embedded in ZnO microplates. The lignin carbon in the composites mainly exists in an amorphous structure, and the specific surface area and pore channels of metal oxides are increased by the presence of lignin carbon. The electrochemical performance test shows that the carbonization temperature of LC/ZnO with the highest specific capacitance is 550 °C, and the capacitance retention rate reaches 96.74% after 1000 cycles of testing, indicating that the composite material has good cycle stability. Compared with the control group, it is found that the specific capacitance of LC/ZnO-550 °C is 2.3 times and 1.8 times that of ZnO-550 °C and LC-550 °C, respectively. This shows that during the electrochemical test, the lignin carbon and the metal oxide promote each other and act synergistically. In addition, the composite material exhibits the characteristics of a pseudo-capacitance capacitor, indicating that the redox reaction occurred in the electrochemical performance test.     

Use of water-dispersible Fe(2)O(3) nanoparticles with narrow size distributions in isolating avidin

Synthetic approaches that vigorously control the microstructures of water-dispersible gamma-Fe(2)O(3) nanoparticles such as size and size uniformity are of importance to the potential biological applications of these nanomaterials. In the present paper, water-dispersible gamma-Fe(2)O(3) nanocrystals with narrow size distributions (bipy-Fe(2)O(3)) were prepared via a site-exchange reaction. These particular materials are superparamagnetic and stable within a wide range of pH. Introduction of the biotin functionality onto the surfaces of bipy-Fe(2)O(3) enabled the affinity isolation of the protein avidin from its incubation solution magnetically with 96% efficiency.     

Encapsulation of uranyl acetate molecules using hollow polymer templates

Crosslinking 4-mercaptostyrene ligands used to protect gold nanoclusters led to a core-shell structure containing a nanometer-sized gold center surrounded with a layer of polystyrene. Sodium cyanide etching of gold from these polymer/gold composite particles generated polymer nanocapsules that were used as hollow templates for encapsulation of uranyl acetate.     

Research on two sides horizontal flame spread over rigid polyurethane with different flame retardants

Journal of Thermal Analysis and Calorimetry - In order to reveal the effect of flame retardant to rigid polyurethane foam (RPUF), a medium-scale experimental platform was built to study horizontal...