四十年峥嵘岁月

中国科学院半导体研究所成立40年了，40年来全所几代人辛勤工作，从无到有，为开创和发展我国半导体科学，为建立我国半导体工业的初步基础以及将半导体技术应用于国防军工作出了重大贡献。作为我国第一代半导体材料科学研究人员，为此而感到欣慰。追忆四十多年的峥嵘岁月，我感到最值得珍惜的是当今艰苦奋斗的创业精神。在庆祝半导体研究所四十周年生日的时候，写出这篇短文与老同志们一起回味共同经历过的甘苦；希望年青的同志们将这种精神发扬光大，让半导体研究所对国家作出更大贡献。

Roles of sorting and chemical weathering in the geochemistry and magnetic susceptibility of Xiashu loess；East China

IEECAS SKLLQG

Measurement of Be-10 in air filters using BeF- ions from BaBeF4

IEECAS SKLLQG

核温度测量与粒子能量的关系

提取了 3 0MeV/u40 Ar+ natAg反应中后角出射的同位素 (6 ,7Li,3,4He)产额比温度为 5MeV .观察到这一同位素产额比温度随阈值能量Ecut/A的增加而逐渐由 5MeV上升到 6MeV .为进一步研究这一变化关系 ,用MonteCarlo方法模拟了热核蒸发粒子的过程 ,表明随粒子能量的增加 ,发射该能量粒子的发射源平均温度也在增加 .说明高温热核发射高能量粒子的几率大 .

1987年特大火灾后不同树种种植比例对大兴安岭森林景观的长期影响

应用空间直观景观模型(LANDIS)模拟了1987年大兴安岭北坡图强林业局特大森林火灾后在目前种植强度下,不同落叶松和樟子松种植比例(100%落叶松(P1)、70%落叶松和30%樟子松(P2)、50%落叶松和50%樟子松(P3)、30%落叶松和70%樟子松(P4)、100%樟子松(P5))以及完全依靠天然更新(P0)条件下森林景观的长期动态变化.结果表明,在演替的前期、中期和后期,不同种植比例均对落叶松、樟子松和白桦有显著影响;落叶松所占的面积百分比随时间的推移均呈上升趋势,而樟子松则相反;在各种植预案下,落叶松和樟子松的面积百分比均高于天然更新预案的比例,随着落叶松种植比例的增加,落叶松的多度也相应增加;樟子松在该区所占的面积百分比也随其种植比例的增大而增加.白桦在天然更新预案下所占的面积百分比明显高于种植预案下所占的比例;而不同落叶松和樟子松种植比例也对白桦面积有较大影响,樟子松种植的比例越大,白桦所占的面积百分比越高,说明落叶松比樟子松有更强的竞争能力.但P2、P3和P4预案下,落叶松和樟子松的面积所占比例相差不大,但要高于完全种植落叶松(P1)或樟子松(P)所占的比例.

A novel approach to synthesis of functional CPVC and CPE or graft copolymers - in situ chlorinating graft

A new process of graft copolymerization of poly(vinyl chloride) (PVC) and polyethylene (PE) with other monomers was developed. The grafted chlorinated poly(vinyl chloride) (CPVC) and chlorinated polyethylene (CPE) were synthesized by in situ chlorinating graft copolymerization (ISCGC) and were characterized. Convincing evidence for grafting and the structure of graft copolymers was obtained using FT-IR, H-1-NMR, gel permeation chromatography (GPC), and the vulcanized curves. Their mechanical properties were also measured. The results show that the products have different molecular structure from those prepared by other conventional graft processes. Their graft chains are short, being highly branched and chlorinated. The graft copolymers have no crosslinking structure. The unique molecular structure will make the materials equipped with special properties.

A new route to control product selectivity in the oxidative dehydrogenation of cyclohexane and cyclohexene

The product selectivity can be controlled by adding acetic acid in feed over vanadium phosphate (VPO) in gas phase oxidative dehydrogenation (ODH), in which cyclohexane and cyclohexene are oxidized to cyclohexene and 1,3-cyclohexadiene (1,3-CHD), respectively, at almost 100% selectivity. This approach is also an efficient method to capture the very unstable intermediates in the mechanism study.

Polydispersity of ethylene sequence length in metallocene ethylene/alpha-olefin copolymers. II. Influence on crystallization and melting behavior

In this work, crystallization and melting behavior of metallocene ethylene/alpha-olefin copolymers were investigated by differential scanning calorimetry (DSC) and atomic force microscopy (AFM). The results indicated that the crystallization and melting temperatures for all the samples were directly related to the long ethylene sequences instead of the average sequence length (ASL), whereas the crystallization enthalpy and crystallinity were directly related to ASL, that is, both parameters decreased with a decreasing ASL. Multiple melting peaks were analyzed by thermal analysis. Three phenomena contributed to the multiple melting behaviors after isothermal crystallization, that is, the melting of crystals formed during quenching, the melting-recrystallization process, and the coexistence of different crystal morphologies. Two types of crystal morphologies could coexist in samples having a high comonomer content after isothermal crystallization. They were the chain-folded lamellae formed by long ethylene sequences and the bundlelike crystals formed by short ethylene sequences. The coexistence phenomenon was further proved by the AFM morphological observation.