Beta Decay of Neutron—Rich Nucleus ^208Hg

The β- decaying γ scheme of the neutron-rich nuclide 208Hg has been determined for the first time.The 208 Hg was produced in multi-nucleon transfer reaction taking place in the bombardment of 18O-beam on natural lead target,and the Hg-element products were sepaated with a gas-thermochromatography technique.The γ-ray single and γ-γ coincident spectra were measured.A partial 208 Hg γ scheme was proposed.Twenty-six γ rays were assigned to follow the β- decay of 208Hg.At the same time,a new level structure of the daughter nucleus 208 T1 was constructed,in which three new levels at 1.725MeV.1.652MeV,and 1.362MeV were affirmed.The experimental 208Tl level structure was compared with a shell-model calculation.     

A SIMPLE PROOF OF THE INEQUALITY FFD (L)≤11/9 OPT(L) 1, ■L FOR THE FFD BIN-PACKING ALGORITHM

The first fit decreasing (FFD) heuristic algorithm is one of the most famous and moststudied methods for an approximative solution of the bin-packing problem. For a list L, letOPT(L) denote the minimal number of bins into which L can be packed, and let FFD(L)denote the number of bins used by FFD. Johnson showed that for every list L, FFD(L)≤11/9OPT(L) 4. His proof required more than 100 pages. Later, Baker gave a much shorterand simpler proof for FFD(L)≤11/9OPT(L) 3. His proof required 22 pages. In this paper,we give a proof for FFD(L)≤11/9 OPT(L) 1. The proof is much simpler than the previousones.     

A SIMPLE PROOF OF THE INEQUALITY R_M(MF(κ))≤1.2+(1/2~κ) IN MULTIPROCESSOR SCHEDULING

We consider the well-known problem of scheduling n independent tasks nonpreemptivelyon m identical processors with the objective of minimizing the makespan. Coffman, Garey andJohnson described an algorithm MULTIFIT, based on bin-packing, with a worst case performancebetter than the LPT-algorithm. The bound 1.22 obtained by them was claimed by Friesen in1984 that it can be improved to 1.2. In this paper we give a simp1e proof for this bound.     

关于三维除数问题

<正> §1.用d_3(n)記将n表成三个因子乘积的表法个数,則有渐近公式此处P_3(log x)为log x的一个二次多項式,也就是ζ~3(x)x~(s-1)/s在极点s=1上的殘数.又用a_3表使     

过碘酸钾氧化鸡冠花红动力学光度法测定食品中痕量碘

基于硫酸介质中，草酸钠作活化剂，碘催化过碘酸钾氧化鸡冠花红而使其褪色的反应，建立了测定痕量碘的新方法。方法灵敏、简便、选择性好。测定碘的线性范围为０－２０μｇ／Ｌ；检出限为０．６６μｇ／Ｌ。用于食品中痕量碘的测定，结果满意。     

催化动力学极谱法测定锰的研究

在Ｎａ２ＨＰＯ４－ＮａＯＨ介质中，Ｍｎ（Ⅱ）能催化过碘酸钾氧化镁试剂Ⅰ的反应，利用极谱法监测催化反应过程中镁试剂Ⅰ的浓度变化，建立了测定锰的催化动力学新方法。该法测定锰的线性范围内５．０～７０ｎｇ·ｍｌ＾－１。检出下限为２．５ｎｇ·ｍｌ＾－１，方法应用于标准钢样和茶叶中锰的测定，结果满意。并对镁试剂Ⅰ的极谱性质进行了初步探讨。     

聚酯-环氧玻璃鋼的研究

本文旨在用环氧树脂改性不饱和聚酯树脂制成玻璃钢,以改善聚酯玻璃钢的机械强度与提高其热稳定性,并保持接触成型的特点。 聚酯-环氧玻璃钢系以聚酯-环氧复合物为粘结剂(不饱和聚酯树脂,#~634环氧树脂,顺丁烯二酸酐,苯乙烯与过氧化苯甲酰的混合物),以0.2毫米厚的斜纹玻璃布为填料,树脂含量控制在35—37％之间,真空浸渍层压而成,并于200℃加热处理1小时。 研究了玻璃布的织法、玻璃布上润滑剂的含量、含胶量及后处理对玻璃钢抗拉强度的影响。 所得的聚酯-环氧玻璃钢的抗弯强度达4600—5390公斤/厘米~2,击穿电压25—28千伏/毫米,马丁耐热>300℃。     

流动注射停流—分光光度法同时测定痕量铝和铁

在弱酸性溶液中，基于铝、铁与铬天青Ｓ、溴化十六烷基吡啶形成蓝色三元络合物，采用两次标准加入法，建立了流动注射停流技术同时测定铝、铁的新方法。测定频率９０次／ｈ。铝、铁的线性范围分别为０－０．４ｍｇ／Ｌ，和０－０．８ｍｇ／Ｌ。应用于水及食品中痕量铝、铁的测定，结果满意。     

非终点滴定法与其应用

为了实现滴定分析的快速和自动化,本文借鉴以往研究的经验针对其不足[1~8],提出了一种新的分析方法,滴定中只要加二次标准液,将采集到的数据通过适当的数学计算,即可得到样品液的浓度,本法不需要已知反应常数、电极转换系数等,对中和度没有严格要求[9~11],故具有可操作性和实用性。本法不需要确定终点,不需要全过程滴定,为滴定分析的自动、快速化提供了充分的条件,特别适合冶金、环境、食品、药品的大批量快速分析和在线分析。根据该方法的原理即可开发出一种新的自动分析仪。