Uniform Drug Loading into Prefabricated Microparticles by Freeze‐Drying

Microparticle‐based drug delivery is a promising technology for small volume bioassay platforms. The general utilization of the drug‐loaded microparticles in the in vitro bioassay platforms requires the drug loading method, which should impregnate the general drug types (e.g., water insoluble) with high payload into the variously designed microparticles. Loading the drug into the prefabricated microparticles using solvent evaporation satisfies the requirement. However, similar to the “coffee‐ring effect,” drugs are loaded in a seriously nonuniform manner, caused by the capillary flow during the evaporation process. Here, it is presented that the freeze‐drying is an efficient way to load uniform and high amount of the drug into the prefabricated microparticles. It is demonstrated that freezing solvent can block the capillary flow during the solvent removal process, improving the loading uniformity. The delivered amount of drugs is linearly proportional to the initial loading amount of drugs. Also, this drug loading method is shown to be applied to the various drug types and the prefabricated microparticles with different properties. Considering many challenges to suppress the “coffee‐ring effect” that induces nonuniform impregnation/deposition, the proposed concept can be applied not only for microparticle‐based drug delivery but also for uniform coating applications (e.g., thin‐film coating, DNA/protein microarray).     

Quantum Image Encryption Based on Iterative Framework of Frequency-Spatial Domain Transforms

A novel quantum image encryption and decryption algorithm based on iteration framework of frequency-spatial domain transforms is proposed. In this paper, the images are represented in the flexible representation for quantum images (FRQI). Previous quantum image encryption algorithms are realized by spatial domain transform to scramble the position information of original images and frequency domain transform to encode the color information of images. But there are some problems such as the periodicity of spatial domain transform, which will make it easy to recover the original images. Hence, we present the iterative framework of frequency-spatial domain transforms. Based on the iterative framework, the novel encryption algorithm uses Fibonacci transform and geometric transform for many times to scramble the position information of the original images and double random-phase encoding to encode the color information of the images. The encryption keys include the iterative time t of the Fibonacci transform, the iterative time l of the geometric transform, the geometric transform matrix G i which is n × n matrix, the classical binary sequences K (\(k_{0}k_{1}{\ldots } k_{2^{2n}-1}\)) and \(D(d_{0}d_{1}{\ldots } d_{2^{2n}-1}\)). Here the key space of Fibonacci transform and geometric transform are both estimated to be 2²⁶. The key space of binary sequences is (2 ^n×n ) × (2 ^n×n ). Then the key space of the entire algorithm is about \(2^{2{n^{2}}+52}\). Since all quantum operations are invertible, the quantum image decryption algorithm is the inverse of the encryption algorithm. The results of numerical simulation and analysis indicate that the proposed algorithm has high security and high sensitivity.     

部分相干Airy光束在大气湍流中的光强演化

为了利用Airy光束的无衍射、自恢复和自弯曲特性抑制大气湍流效应,实现远距离无线光通信,对部分相Airy光束在大气湍流中传输时的光强演化进行了研究.利用高斯-谢尔模型的交叉谱密度函数、广义惠更斯-菲涅尔原理以及Rytov相位近似法,推导了部分相干Airy在湍流大气中平均光强的表达式.分别从传播距离、湍流强度等方面对光强分布的影响进行了模拟仿真,并对光束自身参数对光强分布的影响进行了相关实验验证.结果表明:随着传播距离的增加,部分相干Airy光束的旁瓣逐渐衰减,主瓣逐渐扩散;在传播足够远时,其旁瓣逐渐消失,主瓣逐渐演化为高斯分布.仿真和实验结果一致表明光束的截断因子越小、特征长度和相干长度越长,光束的光强分布保持越完整.     

Z箍缩驱动聚变-裂变混合堆氚燃料循环系统氚盘存量与氚自持初步分析

为研究氚自持条件,建立了Z-FFR氚分析模型,基于理论方程和氚平均滞留时间方法进行计算,得到稳态运行时排灰气处理系统、氚增殖提取系统、同位素分离系统、水去氚化系统的氚质量流分别为52.30,25.40,81.30,3.60 g/day,对应的氚盘存量为52.30,25.40,8.13,1.80 g。同时以氚质量流推导出氚自持判断条件,分析了设计参数能够满足氚自持要求,同时获得了燃烧效率、氚增殖率、提取效率与氚自持的互补关系,三者作为关键参数相互依存,于临界值、设计值、理想值之间分析了氚的自持情况。     

辐射成像系统模拟软件NUCRPD的研发与应用

在辐射成像系统的设计研发中,经常需要计算系统的各项物理性能指标。为了提升产品研发的效率,同方威视联合清华大学,基于蒙特卡罗程序包Geant4,研发了国内首套具有自主知识产权的辐射成像系统模拟软件NucRPD(NUCTECH Radiography Performance Design Tools),其能够快速、精确地模拟系统的各项性能指标。该软件对常用的一些辐射成像系统进行了参数化建模,用户通过修改软件界面上的少量参数,就可以快速建立各类辐射成像系统的几何体、源项、物理模型和统计量,然后在服务器上以并行计算方式完成模拟计算,能在较短的时间内模拟出系统的性能指标,并给出直观的图形帮助用户深入理解模拟结果。NucRPD的模拟结果经过了大量的实验验证,其剂量场分布和物理指标等模拟结果和实验结果符合得很好。NucRPD已经应用于同方威视辐射成像系统产品的设计研发,在产品的物理指标优化和辐射防护优化中发挥了重要作用。     

氮化镓基感光栅极高电子迁移率晶体管器件设计与制备

GaN基高电子迁移率晶体管(HEMT)作为栅控器件,具有AlGaN/GaN异质结处高浓度的二维电子气(2DEG)及对表面态敏感等特性,在栅位置处与感光功能薄膜的结合是光探测器领域重要的研究方向之一.本文首先提出在GaN基HEMT栅电极上引入光敏材料锆钛酸铅(PZT),将具有光伏效应的铁电薄膜PZT与HEMT栅极结合,提出一种新的"金属/铁电薄膜/金属/半导体(M/F/M/S)"结构;然后在以蓝宝石为衬底的AlGaN/GaN外延片上制备感光栅极HEMT器件.最后,通过PZT的光伏效应来调控沟道中的载流子浓度和通过源漏电流的变化来实现对可见光和紫外光的探测.在365 nm紫外光和普通可见光条件下,对比测试有/无感光栅极的HEMT器件,在较小V_(gs)电压时,可见光下测得前者较后者的饱和漏源电流I_(ds)的增幅不下降,紫外光下前者较后者的I_(ds)增幅大5.2 mA,由此可知,感光栅PZT在可见光及紫外光下可作用于栅极GaN基HEMT器件并可调控沟道电流.     

关于93Mo中21/2+晕阱的来源(英文)

本研究通过壳模型计算研究了N=51的同中子素91Zr、93Mo和95Ru中高自旋晕态21/2+的同核异能态现象。计算发现,低角动量的p_1/2轨道上的质子是仅在93Mo中存在21/2+晕阱的主要原因。同时,本工作还研究了N=52的同中子素92Zr、94Mo和96Ru中10₁+-12₁+能级结构的系统性,发现94Mo中的10₁+-12₁+能级间隙相对最小,考虑到与93Mo的17/2₁+-21/2₁+能级相似的组态,这一结果为93Mo中出现21/2+晕阱提供了补充性的论证。Isomerism of the high-spin yrast 21/2+ states of the N=51 isotones 91Zr, 93Mo and 95Ru has been investigated using the shell model calculations. It is found that the low-j πp_1/2 is responsible for the only yrast trap in 93Mo. In addition, the relatively smaller 10₁+-12₁+ level spacing in 94Mo has been found by investigating the systematics of the 10₁+-12₁+ level structures in the N=52 isotones 92Zr, 94Mo and 96Ru. This result provides a supplementary argument to the origin of the 21/2+ yrast trap in 93Mo from the viewpoint of the similarity between the configurations of 10₁+-12₁+ states in 94Mo and those of 17/2₁+-21/2₁+ states in 93Mo.     

电子直线加速器束流均方根发射度变化方程

本文导出了考虑外场和束流效应后束流均方根发射度平方变化方程的一般表达式,并就仅考虑外场,仅考虑空间电荷场和仅考虑尾场等三种特殊情况进行了分析。     

Measurements of the perpendicular width of ionization-produceddouble layers

Measurements of the perpendicular (to B) double-layer widths of ionization-produced (anode) double layers are presented. These widths were determined from measurements of the double-layer charge separations. The variations of the transverse-to-B widths with plasma density and magnetic field strength are given