Stem cell transplantation and intensified cytotoxic treatment for myelodysplasia

At least three questions has to be answered by imaging methods, when new therapies in acute ischemic stroke should be used: 1. Is there a cerebral ischemia? 2. What is the size of the irreversible damaged tissue and what is the size of the safeable tissue? Is there still a vessel occlusion? New MRI-techniques including MR-angiography, diffusion-weighted imaging and perfusion-MRI, have the potential to describe the status of the brain in detail and to answer these questions. However, the value of these techniques for therapeutical decisions (thrombolysis) is unclear and has to be evaluated in clinical studies. Therefore in clinical routine these decisions should still be based on informations from CT and perhaps CT-angiography.     

液相法制备纳米钯粉的工艺研究

采用液相法,以Pd粉为原料,分别用HCHO,HCOOM,C2H4H2O作还原剂,把钯还原成纳米粉末。通过控制反应体系的pH值、浓度、温度及还原剂的种类和还原时间来控制粉末的粒径大小及其分布.实验结果表明:利用本法制备的Pd粉粒径在9 nm~20 nm,粒度分布均匀而且重现性好,适用于制造钯银导体浆料.     

放射性铌铁精矿中铀钍脱除及分离

通过对国内某企业进口放射性铌铁精矿进行工艺矿物学分析,确定该精矿的主要矿相为烧绿石,同时伴生钛铁矿和白云母,矿石中放射性元素U和Th的含量分别为0.27%和1.03%。针对该铌铁精矿,探索H2SO4-Fe(Ⅲ)、H2SO4-HF-H2O2、H2SO4-HF、H2SO4-HF-H2O2-(NH4)2CO3体系中U和Th的浸出及分离效果,最终确定H2SO4-HF-H2O2-(NH4)2CO3多段浸出工艺能有效实现U和Th的脱除与分离。U、Th的脱除率分别为100%和80%。基于研究提出了铌铁精矿U、Th脱除及分离工艺流程。     

高能同步辐射光源逐束团束流位置测量电子学研制

基于高能同步辐射光源（HEPS）储存环,研制了一套逐束团束流位置测量（BPM）电子学系统,电子学的硬件部分由模拟信号采集板卡和数字信号处理板卡组成,软件部分由底层固件和顶层应用软件组成。系统的采样频率为500 MHz,带宽为1 GHz,对来自储存环BPM探头的4路模拟信号进行数字化,得到束团幅度数据,利用ZYNQ芯片计算出每个束团在真空管道中的位置。逐束团BPM电子学在实验室的测试结果为：输入信号峰峰值小于1.8 V时ADC通道非线性度小于1%,无杂散动态范围约60 dB,灵敏度系数取8.26 mm时位置分辨率优于10 μm,测试结果满足HEPS逐束团BPM的需求。     

Fasciola hepatica development in the experimentally infected black rat Rattus rattus

Coat colour changes in polar animals are related to seasonal variation in photic inputs. The present work was performed to study the photoresponses of hair follicular melanocytes in human skin. The melanocytes, being photosensitive cells, can function as UV biosensors, since dendrites extend towards the source of UV light. Fifty-one skin biopsies from the margin of vitiligo were subjected to whole skin organ cultures. These were exposed to a pulse of UV light to study hair bulb melanocytes in vitiligo. It is observed that the melanocytes are seen within the anagen matrix. These melanocytes are poorly dendritic in control and dark-incubated cultures. On UV exposure, they become highly dendritic, the dendrites extending towards the hair shaft in 93.5%. They show prominent catechol oxidase and noradrenaline positivity, all features of UV responsiveness. The melanocytes within the hair follicle are not directly exposed to UV light. The melanocyte dendricity and the alignment of dendrites towards the shaft on UV exposure indicate that the columns of the cells in the hair shaft act as an efficient fibre-optic system, transmitting UV light. Morphologically, the keratinocytes in the hair shaft are arranged in compressed linear columns which resemble the coaxial bundles of commercial fibre-optic strands as is observed in plants. Keratinocytes in the inner and outer sheaths do not show this arrangement. Thus the hair follicle functions as a specialised UV receptor in the skin responding to nuances of photic inputs in human skin. This is reflected in coat colour changes in animals exposed to large variations in day-night cycles.     

Study on Compound Effect of Bonded Magnets

The compound effect of Nd2Fe14B/Fe3B-Ferrite bonded magnets was studied.The result shows that the value ofβjHC obviously decreases with the ferrite content increasing.In addition, a functional relation between magnetic properties and ferrite content was clearly revealed by the physical relation in the magnetic powders.     

同步电动机励磁系统的应用

采用由数字化控制技术单片机系统构成的BKL-501H微机励磁装置，对由发电机组构成的第一代同步电动机励磁装置进行改造，叙述了改造前存在的问题和改造后的特点。     

中子标准的国际比对

本文介绍了国际计量局(BIPM)组织的最近进行的中子标准的国际比对,包括中子源的发射率,中子注量和能量,中子剂量的比对。并给出了部分比对结果。     

中国大陆进口冷链食品关联新型冠状病毒疫情调查

目的 新型冠状病毒（SARS-CoV-2）全球大流行以来,中国大陆报道了多起SARS-CoV-2污染进口冷链食品引起的本土新冠疫情,分析此类疫情的特点和传播概况,可以为今后类似疫情防控提出相应建议。方法 收集SARS-CoV-2污染进口冷链食品引起本土新冠疫情文献、官方新闻报道等信息,整理和分析相应数据。结果 2020年6月至2022年11月,共检索到此类疫情20起,包含1 646例病例,涉及9个省（自治区、直辖市）。其中,2020年10起,2021年3起,2022年7起;病例数规模在200例及以上共3起。结论 新冠全球大流行以来中国大陆检索到的20起进口冷链食品相关本土新冠疫情均为冷链从业人员接触进口冷链食品或其外包装感染引起,且大部分（75%）引起了后续社区传播,但是在中国大陆集中监管仓建设等各种有力控制措施下,此类疫情数量和持续时间均呈下降趋势。     

永磁同步电动机混沌系统的串级控制

根据永磁同步电动机的数学模型,研究如何运用串级PD控制器来控制混沌.首先在理论上运用劳斯(Routh)判据分析永磁同步电动机模型串级PD控制混沌的可行性,然后通过在平衡点处线性化的雅克比(Jacobian)矩阵来求取PD参数的值.最后在MATLAB/Simulink仿真平台上利用数值仿真实验验证其有效性.通过研究可知,运用串级PD控制可以较好地消除混沌使系统达到一个稳定的状态.该方法具有一定的参考实用性,为永磁同步电动机混沌运动分析或控制打下了研究基础.