First nuclear transmutation of 237Np and 241Am by accelerator-driven system at Kyoto University Critical Assembly

This study demonstrates, for the first time, the principle of nuclear transmutation of minor actinide (MA) by the accelerator-driven system (ADS) through the injection of high-energy neutrons into the subcritical core at the Kyoto University Critical Assembly. The main objective of the experiments is to confirm fission reactions of neptunium-237 (²³⁷Np) and americium-241 (²⁴¹Am), and capture reactions of ²³⁷Np. Subcritical irradiation of ²³⁷Np and ²⁴¹Am foils is conducted in a hard spectrum core with the use of the back-to-back fission chamber that obtains simultaneously two signals from specially installed test (²³⁷Np or ²⁴¹Am) and reference (uranium-235) foils. The first nuclear transmutation of ²³⁷Np and ²⁴¹Am by ADS soundly implemented by combining the subcritical core and the 100 MeV proton accelerator, and the use of a lead-bismuth target, is conclusively demonstrated through the experimental results of fission and capture reaction events.     

ADS熔盐散裂靶中子学性能研究

与传统加速器驱动次临界系统（ADS）采用金属靶作为散裂中子靶的设计不同，加速器驱动次临界熔盐堆（AD-MSRs）采用靶堆一体的设计，直接使用燃料熔盐作为散裂中子靶。由于熔盐靶的中子学性能直接影响AD MSRs的能量放大系数、核废物的嬗变和核燃料增殖的效率，所以本研究基于MCNPX程序，详细计算了高能质子轰击氟盐和氯盐两种熔盐靶产生的散裂中子产额、散裂中子能谱、能量沉积分布以及散裂产物等中子学性能，并与液态Pb和铅铋共熔体（LBE）两种液态金属靶进行了对比。计算结果表明，熔盐靶在散裂中子产额上与液态金属靶有一定的差距，但熔盐靶内能量沉积分布的梯度较小，更有利于靶区的热量导出。与液态Pb和LBE靶相比，熔盐靶的散裂产物中包含更多的气体以及高质量数的α发射体核素。     

Hydrogen production methods efficiency coupled to an advanced high-temperature accelerator driven system

Hydrogen, rather than oil, must be produced in volumes not provided by the currently employed methods. In this work, two high-temperature hydrogen production methods coupled with an advanced nuclear system are presented. A new design of a pebble-bed accelerator nuclear-driven system called TADSEA (Transmutation Advanced Device for Sustainable Energy Applications) was chosen because of the advantages in transmutation and safety. A detailed flowsheet of the high-temperature electrolysis process coupled to TADSEA through a Brayton gas cycle was developed using chemical process simulation software: Aspen HYSYS^®. It is obtained 0.1627 kg/s of hydrogen with the model with optimized operating conditions, resulting in an overall process efficiency of 34.51%, a value in the range of results reported by other authors. A conceptual design of a plant using the iodine-sulfur thermochemical water splitting cycle was carried out producing 5.66e-2 kg/s and electric energy in cogeneration. The overall efficiency was calculated performing an energy balance resulting in 22.56%. A brief hydrogen production cost estimation was performed for both methods obtaining 5.96$/kg for the sulfur-iodine (SI) and 4.8 $/kg for the high-temperature electrolysis (HTE) process.     

Oxygen concentration measurement and control of lead-bismuth eutectic in a small,static experimental facility

ABSTRACT

Oxygen measurement and control system is critical for minimizing corrosion in nuclear systems. Oxygen measurement and control tools use lead-bismuth eutectic (LBE) and pure lead as a coolant or as a spallation target. Oxygen can be supplied by either gas phase (H₂O or O₂) or solid phase (PbO dissolution); thus, oxygen control includes both gas phase and solid phase methods. This article focuses on oxygen concentration measurement and control of lead-bismuth eutectic in a small, static experimental facility. This facility was developed for oxygen sensor calibration and gas/solid phase control systems test programs. The oxygen sensor with Nano Cu/Cu₂O closely the Nernstian behavior down to 195°C; the oxygen sensor measurement accuracy satisfied the requirements of subsequent experiments. The gas phase control system (verified according to different type of mass transfer, such as air, H₂O, gas injection, and coverage) and the solid phase control system were very successful in small experimental devices. Accurate oxygen concentration control was achieved with both the gas and solid phase control systems.     

大型岩土体数值计算实施与autoCAD联接的主要途径

本文介绍了大型岩土体数值计算程序与autoCAD联接，实现其图形前后自动处理的命令组文件（SCR）、绘图交换文件（DXF）、autoLISP语言及C语言接口（ADS）等几种方法。     

稳定平台中通用陀螺数据采集处理系统

为提高稳定平台的性能,针对平台中各种类型陀螺高速度、高精度、宽动态范围的设计指标要求,研制了一种通用数据采集处理系统。在详细分析动力调谐、光纤和微机械陀螺典型型号性能参数指标的基础上,提出了系统的设计指标要求,选择8通道24位∑-？高精度模数转换器ADS1278和32位数字信号处理器TMS320F2812,设计实现系统的硬件电路,编写了相关的软件程序,并进行了实验验证。实验表明：系统的转台测试数据与陀螺出厂标定的性能参数之间,测量误差小于1%,完全满足稳定平台中陀螺的应用要求。     

Design and performance analysis of cylindrical surrounding double-gate MOSFET for RF switch

In this paper, we have analyzed the design parameters of Cylindrical Surrounding Double-Gate (CSDG) MOSFETs as an RF switch for the advanced wireless telecommunication systems. The proposed CSDG RF MOSFET is operated at the microwave regime of the spectrum. We emphasize on the basics of the circuit elements such as drain current, threshold voltage, resonant frequency, resistances at switch ON condition, capacitances, energy stored, cross talk and switching speed required for the integrated circuit of the radio frequency sub-system of the CSDG RF CMOS device and the physical significance of these basic circuit elements is also discussed. We observed that the total capacitance between the source to drain for the proposed CSDG MOSFET is more compared to the Cylindrical Surrounding Single-Gate (CSSG) MOSFET due to the greater drain current passing area of the CSDG MOSFET, which reveals that the isolation is better in the CSDG MOSFET compared to that of the simple double-gate MOSFET and single-gate MOSFET. We analyzed that the CSDG MOSFET stores more energy (1.4 times) as compared to the CSSG MOSFET. Therefore, the CSDG MOSFET has more stored energy. The ON-resistance of CSDG MOSFET is half than that of the double-gate MOSFET and single-gate MOSFET, which reveals that the current flow from source to drain in CSDG MOSFET is better than the double-gate MOSFET and single-gate MOSFET.     

突发直接序列扩频发射系统的分析与仿真

针对强干扰环境下的短时突发扩频发射系统,介绍了扩频通信的基本原理和性能参数,并以处理增益为指标分析了 突发直扩系统的抗干扰能力.通过理论分析提出了发射系统总体的设计框图,通过ADS仿真平台对该发射信号进行了仿真,搭建了直接序列扩频发射信号仿真模型.最后分析发射信号的频谱图和星座图,验证该发射方案的可行性.     

5.8GHzWiMAX低噪声放大器设计与仿真

介绍了一种基于IEEE802.16标准的高频段WiMAX低噪声放大器(LNA)的设计方法,工作频段在5.8 GHz,采用稳 茂0.15 μm pHEMT工艺4×50 μm晶体管大信号模型,选用Current-Reused结构作为LNA电路结构,并优化设计LNA的电路 偏置电路.利用Agilent公司的 ADS2008 ...     

基于软件无线电跳频电台射频前端的研究

基于软件无线电的基本要求和发展趋势,提出了一种应用在软件无线电跳频电台中宽频段接收机的前端电路设计方案,分析了接收机射频前端二次混频方案结构的可行性,在对方案中各功能模块研究分析的基础上,完成了射频前端的滤波器、混频器、放大器等各模块的设计工作,并对整个系统进行了建模设计和仿真验证。仿真结果表明,接收机前端电路噪声系数低,镜像抑制良好,增益合理,选择性合适,均满足设计要求。