反熔丝FPGA的电离总剂量效应与加固技术

简要叙述了商用FPGA用于空间领域时面临的抗电离总剂量加固总是，对Actel公司反熔丝FPGA的电离总剂量效应进行了较为详细的分析，包括制造了工艺，偏置条件，电泵对总剂量效应的影响，并特别指出，电泵的退化可能会对系统造成较为严重的后果，因此，必须重视加电后的瞬态变化，提出了可以采取的加固措施。     

SiGe HBT与Si BJT的~(60)Co射线总剂量辐照效应比较

研究了国产结构参数近似的SiGe HBT与Si BJT在60Coγ射线辐照前和不同剂量辐照后性能的变化,并作了比较。辐照后集电极电流Ic变化很小,基极电流Ib明显增大,表明辐照后电流增益的下降主要是由于Ib的退化所导致。当辐照剂量达到10kGy(Si)时,SiGe HBT和Si BJT的最大电流增益分别下降为77%和55%,表明了SiGe HBT具有比Si BJT更好的抗γ射线辐照性能。对辐射损伤机理进行了探讨。     

Note on Furchtgott's "Behavioral effects of ionizing radiations: 1955-61."

Extremely low doses of ionizing radiation operate as complex stimuli with both cue and aversive properties. Recent studies have demonstrated that effects can be obtained with total doses of less than 1 roentgen. This fact may explain some of the controversies concerning radiosensitivity of mammals and the conflicting results obtained in behavioral and electroencephalographic tests for effects of radiation exposure recently reviewed in this journal. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Behavioral effects of ionizing radiations.

The effects of high-energy radiation on pre- and neonatal development, the adult nervous system, learning and performance, and sensory functions are described. Though the number of available studies are few, there is evidence to suggest that: (1) the adult nervous system is relatively radioresistant; (2) learning functions are relatively unaffected by lethal or sublethal dosages of radiation; (3) hearing acuity and thresholds to dark adaptation increase as a result of radiation; and (4) the fetal nervous system is relatively radiosensitive. There is a need for more studies assessing the behavioral effects of radiation. 70-item bibliography. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

基于离散放电模型的双栅极空气计数器工作电压算法

基于双栅极空气计数器放电过程和脉冲形成过程,建立了离散化放电模型,指出总放电脉冲幅度是各电离自由程产生电子的贡献之和,并据此得出计数器工作电压与计数器几何参数、电路灵敏度及放电量之间的关系,提出了一种计数器工作电压的新算法,给出了优化措施。算例说明这种算法可以用于双栅极空气计数器的设计。     

辐射化学在煤加工中的应用

主要介绍了国内外用电离辐射强化煤加工过程的方法与进展,分析了煤脱硫、共热解、烟道气处理过程中应用的辐射化学原理,并提出了辐射化学原理应用于煤加工转化的新设想．     

Gate-enclosed NMOS transistors

In order to quantitatively compare the design cost and performance of various gate styles,NMOS transistors with two-edged,annular and ring gate layouts were designed and fabricated by a commercial 0.35μm CMOS process.By comparing the minimum W/L ratios and transistor areas,it was found that either the annular layout or its ring counterpart incurs a higher area penalty that depends on the W/L ratio of the transistor to be designed. Furthermore,by comparing the output and transfer characteristics of the transistors and analyzing the popular existing methods for extracting the effective W/L ratio,it was shown that the mid-line approximation for annular NMOS could incur an error of more than 10%.It was also demonstrated that the foundry-provided extraction tool needs significant adaptation when being applied to the enclosed-gate transistors,since it is targeted only toward the two-edged transistor.A simple approach for rough extraction of the W/L ratio for the ring-gate NMOS was presented and its effectiveness was confirmed by the experimental results with an error up to 8%.     

Modeling operation amplifier based on VHDL-AMS for TID effect

A model of the operational amplifier based on VHDL-AMS is proposed. According to needs of simulating the total ionizing dose(TID) radiation effect, parameters of operational amplifier are taken into account when the performance is specified. The operational amplifier model used for the TID radiation effect simulation is completed after verifying each modeled parameter. And a parameter for describing the external environment is introduced to make the model combined with TID. Finally, an example is used to illustrate the TID effect on the operational amplifier of MC14573, proving the validity of the model.     

Total ionizing dose sensitivity of function blocks in FRAM

The total ionizing dose (TID) sensitivity of the function blocks, including the memory array, sense amplifier, row decoder, column decoder and I/O port, of the ferroelectric random access memory (FRAM) are investigated. An X-ray microbeam is used for the selective irradiation and detailed detection. The ferroelectric memory array is proved to have higher resistance to TID than the peripheral control circuitry, whereas the sense amplifier is the most sensitive parts in the FRAM circuitry. The failure phenomenon is studied when each function block is irradiated, and the failure mechanism is discussed based on each block’s technological and circuital characteristics. In addition, the Co-60 γ ray irradiation test is also performed to offer a comparison of the spot and global irradiation.     

Preliminary investigation on the design of biodegradable microparticles for ivermectin delivery: set up of formulation parameters

The aim was to design sterile biodegradable microparticulate drug delivery systems based on poly(dl-lactide) (PLA) and poly(?-caprolactone) (PCL) and containing ivermectin (IVM), an antiparasitic drug, for subcutaneous administration in dogs. The drug delivery system should: (i) ensure a full 12-month protection upon single dose administration; (ii) be safe with particular attention regarding IVM dosage and its release, in order to prevent over dosage side effects. This preliminary work involves: polymer selection, evaluation of the effects of γ-irradiation on the polymers and IVM, investigation and set up of suitable microparticle preparation process and parameters, IVM-loaded microparticles in vitro release evaluation.

Results of gel permeation chromatography analysis on the irradiated polymers and IVM mixtures showed that combination of IVM with the antioxidant α-tocopherol (TCP) reduces the damage extent induced by irradiation treatment, independently on the polymer type.

Solvent evaporation process was successfully used for the preparation of PLA microparticles and appropriately modified; it was recognized as suitable for the preparation of PCL microparticles. Good process yields were achieved ranging from 76.08% to 94.72%; encapsulation efficiency was between 85.76% and 91.25%, independently from the polymer used. The type of polymer and the consequent preparation process parameters affected microparticle size that was bigger for PCL microparticles (480–800?µm) and solvent residual that was >500?ppm for PLA microparticles. In vitro release test showed significantly faster IVM release rates from PCL microparticles, with respect to PLA microparticles, suggesting that a combination of the polymers could be used to obtain the suitable drug release rate.