北京地区膳食摄入^232Th吸收入体液份额f1值的探讨

从北京地区公众成年人~(232)Th 的膳食日食入量,空气日吸入量,以及骨中~(232)Th 的沉积量出发,利用 ICRP 30号报告中参考人的代谢参数和内照射的库室模型,估算了北京地区公众成年人膳食摄入~(232)Th 后经胃肠道向体液转移份额 f_1值。结果表明,对于公众中成年人0.005是 f_1值的合适代表值,是 ICRP 30号报告推荐值 f_1=0.0002的25倍。虽然 ICRP 推荐值并不用于公众,但可以对群体有所了解;而北京地区从实测数据资料出发导出的 f_1值可能是更适于公众的。     

OMAPL138和FPGA的合并单元设计方案

提出了一种基于ARM9+DSP双核处理器OMAPL-138和FPGA的合并单元设计方案。给出了该方案的原理框图,以及具体的程序流程图,并在CCS开发环境下完成了软件编程,实现了合并单元按照IEC61850标准规定的格式进行数字量以太网传输。实验结果证明了该设计方案的可行性与正确性,为合并单元的设计提供了一种新的思路。     

Measurement of Thermal Neutron Cross Section of 137Cs(n, γ)138Cs Reaction

A calculational model for a modified diffusion coefficient has been developed to incorporate the neutron streaming effect in heterogeneous low-density channels accurately into diffusion theory calculations. The model uses a supercell, and the axial and radial diffusion coefficients of the heterogeneous inner cell are so defined that they can reproduce Benoist's axial and radial diffusion coefficients of the supercell when the diffusion coefficient of the outer cell is given as 1/3 Σ_tr . In the case of the axial diffusion coefficient, the axial buckling effect is taken into account by modifying the neutron path length within the streaming channel in calculating the collision probabilities. This model has been applied to an RZ fast reactor Core model with a gas expansion module (GEM). By using the axial diffusion coefficient obtained with the presented model, calculational error of GEM worth was reduced to less than 1/7 compared to the formula of Rowlands and Eaton.     

基于OMAPL138的嵌入式CNC控制器硬件平台开发

针对基于PC机和专用运功控制卡的传统数控系统的不足,以及基于ARM和DSP的多处理器在通信上的不足。提出基于多核异构的OMAPL138处理器的嵌入式处理方案,构建CNC控制器的硬件控制系统,同时利用FPGA的现场可编程特性完成控制器扩展模块设计。该设计解决了PC机所缺乏的实时性以及资源的专用性问题和多处理器通信数据丢失、易出错、难维护的缺陷,并实现了现代CNC系统所需求的高性能、模块化、柔性化以及开放性。     

多路开关状态检测

通过使用74HC245、74HC138以及AT89S52设计了一种用于多路开关状态检测的系统,74HC245有一个低有效的OE使能端,同时74HC138的输出也是低有效的,这样一个74HC138的输出就能控制8个74HC245的OE端。同时74HC245有8个输入管脚,因此,通过适当地设计74HC245的前端电路,就能同时对64路开关的状态进行有效地检测。设计仅占用了11个AT89S52的管脚资源,设计成本非常低,同时系统稳定性也非常高。     

基于OMAPL138的高速信号处理系统信号完整性分析

以基于OMAPL138的高速数字信号处理系统为例,分析了信号完整性在高速电路设计中的重要性及问题产生原因,通过仿真提出了信号完整性问题中的反射和串扰的解决方案,并具体阐述了在实际工程设计中如何控制高速信号的时序,以及如何保证电源系统的完整性。实践证明,高速数字电路设计中,保证信号完整性可以有效的保障系统的稳定运行,提高设计的一次成功率。     

OMAPL138的光电任务载荷控制器设计

针对无人机光电任务载荷轻量化、小型化和高性能的需求,本文基于 ARM＋DSP 的双核异构 OMAPL138处理器,设计了一种兼具多任务管理和伺服稳定控制功能的光电任务载荷控制器。设计中扩展了8通道 EMIF总线接口方式的串口,运用了 GDB和CCS相结合的动态双核调试法,实现了利用消息队列和环形缓冲区的核间通信,完成了光电任务载荷的高效准确控制。该设计改善了控制器的体积和功耗,提高了核间通信的速度与可靠性,具有一定的工程应用价值。     

基于Protues的16×32点阵LED汉字显示屏的开发

Proteus是世界上著名的仿真软件,实现了电路仿真软件、PCB设计软件和虚拟模型仿真软件三合一的设计平台。该文介绍利用Proteus仿真软件开发的基于单片机的16×32点阵LED汉字显示屏,实现了LED点阵屏核心功能即汉字、数字、字母的多样化显示。     

Expression of CD40 and CD40L in Gastric Cancer Tissue and Its Clinical Significance

To study expression of CD40 and CD40L in gastric cancer tissue we assessed gastric cancer patients admitted to the Department of Gastroenterology of The First Affiliated Hospital of Soochow University and control subjects. Gastric cancer and normal (from around tumours) tissue samples were obtained from patients. Venous blood samples (gastric cancer and ulcer groups) were drawn on the morning of the day before surgery for the measurement of peripheral sCD40L. The expression of CD40 in gastric carcinoma specimens was examined immuno-histochemically. The clinicopathological factors, including age, sex, tumor size, gross appearance, degree of cellular differentiation, histological classification, depth of tumor invasion, lymph node metastasis, peritoneal dissemination, and TNM stage were analyzed according to the different expression of CD40. The results indicated a high CD40 expression in gastric cancer tissues. This positive expression of CD40 revealed a significant (P < 0.05) correlation with lymphatic metastasis and tumor TNM stage in gastric cancer patients. It is concluded that higher CD40 expression existed in expanding type tumors and could play an important role in clinical diagnosis of gastric cancer patients.     

基于CPLD的OMAP-L137与ADS1178数据通信设计

介绍高精度采样芯片ADS1178及新型工控芯片OMAP-L137,并采用SPI接口结合CPLD控制芯片,实现OMAP-L137与ADS1178间的数据通信。测试表明,既节约了处理器资源,又满足了工业环境中各类控制系统数据采集的实时性和准确性的要求。