Si-Cu合金化渣剂精炼去除冶金级硅中金属杂质

采用Si-Cu合金精炼与CaO-SiO2-CaCl2造渣精炼相结合的方法对冶金级硅进行精炼,通过多种分析方法考察了合金造渣过程、渣剂添加剂和合金成分对金属杂质铁（Fe）、铝（Al）和钙（Ca）去除效果的影响。结果表明,提高Si-Cu合金中的Cu含量可以有效增加Cu3Si相在Si中的含量,合金造渣过程会产生多而弥散的合金相,造渣后的金属杂质Fe、Ca聚集在Si-Cu合金的Cu3Si相中。在渣剂中添加CaCl2助溶剂可有效提高金属杂质Fe、Al和Ca的去除率。此外,随着Si-Cu合金中Cu含量的增加,Cu在合金中的析出现象明显,Fe的去除率上升,Al的去除率不变,Ca的去除率下降。当Si-30%Cu合金与45%CaO-45%SiO2-10%CaCl2渣剂进行精炼后,Fe的去除率为68%,Al的去除率为94%,Ca的去除率为86%

Effect of different tillages on soil physical properties of dryland wheat field in the Loess Plateau

通过冬小麦田间试验,研究了免耕、深松、翻耕三种不同耕作措施对土壤物理特性的影响。结果表明:冬小麦收获时,免耕与其它处理相比,增大了土壤容重、土壤硬度,其土壤干筛法>0.25 mm团聚体含量比深松和翻耕每层平均增加3%和5%,但较冬小麦耕作处理前每层平均下降5%;免耕条件下,湿筛法>0.25 mm团聚体含量比深松和翻耕每层平均增加11%和32%,较冬小麦耕作处理前每层平均下降42%;免耕可增加土壤蓄水量,收获期土壤蓄水量为373.1 mm,较深松和翻耕提高17%和8%;随着降水量的增加,冬小麦收获期水分入渗速率逐渐减少;且不同耕作方式水分入渗速率为免耕>深松>翻耕

低能~(16)O~+离子微剂量学研究

用圆柱型流气式组织等效正比计数器测定了K 2 0 0kV低能重离子加速器提供的低能16O+离子束流在穿过 4μm厚的PET(C10 H8O4 )薄膜后的微剂量谱和径向剂量分布。测定了穿过不同厚度PET薄膜后的16O+ 束流的单次事件剂量平均比能zID随束流强度的变化曲线。用TIRM 92MonteCarlo程序计算了16O+ 离子在PET材料中的射程 ,与实验结果进行了比较和讨

用圆柱型流气式组织等效正比计数器测定α粒子微剂量谱

研制并调试了圆柱型流气式组织等效正比计数器；装配了组织等效气体的配气系统斥ｖ用该装置测定了２３９Ｐｕα粒子的微剂量谱。A cylindrical flowing tissue equivalent proportional counter was made and adjusted. The tissue equivalent gas providing system and the electronic system designed for the CFTEPC were described. The microdosimetric spectra of α particles from 239Pu in TE and CH4 gases were measured.国家自然科学基

~(239)Pu α 粒子的微剂量谱和径向剂量分布

用大容积（６０ｍｍ×８０ｍｍ）的圆柱型流气式组织等效正比计数器测定了２３９Ｐｕα粒子的微剂量谱和径向剂量分布。α粒子束在无窗的情况下直接穿入正比计数器，由离子穿过而发生能量沉积的机率Ｒｂ为１。测量结果证实：沿α粒子径迹由单次事件沉积的剂量平均比能ｚ１Ｄ（Ｇｙ）与距径迹核径向距离ｂ（μｍ）之间完全符合ｚ１Ｄ＝ａｂ－２的函数关系，同时给出了求出最大径向距离（ｐｅｎｕｍｂｒａ）的方法。Microdsimetric spectra and radial dose distribution of 239 Pu α particles were measured by the cylindrical flowing tissue equivalent proportional counter with larger volume. Because of the best collimated beam traverse in TEPC (tissue equivalent preportional courreer), the probability of energy deposition per ion traversal R b is 1. The measured dose mean specific energy z 1D from single event varies strictly in accordance with formula z 1D = ab -2 , b is the radi...国家自然科学基

~(252)Cfα粒子的微剂量谱和径向剂量分布

用大容积(φ60mm×80mm)的圆柱型流气式组织等效正比计数器测定了~(252)Cfα粒子的微剂量谱和径向剂量分布.α粒子束在无窗的情况下直接穿入正比计数器发生能量沉积的机率R_b为1.测量结果证实:沿α粒子径迹由单次事件沉积的剂量平均比能z_(1D)(Gy)与距径迹核径向距离b(μm)之间符合z_(1D)=ab~(-x)的函数关系,当b<0.6482μm时,α=0.328,x=1.7;当b≥0.6482μm时,α=0.288, x=2.给出了求最大径向距离的方法.Microdosimetric spectra and radial dose distribution of 252 Cf a particles were measured by a large volume cylindrical flowing tissue-equivalent proportional counter(TEPC). Because a particles enter into the TEPC without a window, the probability of energy deposition per ion Rb is 1. The measured dose-mean specific energy z1D(Gy) from single-event varies with b the radial distance from the track core, according to the formula z1D=ab-x. where a = 0.328 and x=1.7 when b<0.6482 μm. and a = 0.288 and x = 2 ...国家自然科学基金资