RBa_2Cu_4O_8(R=Dy,Ho,Er,Tm,Yb)和Y_2Ba_4Cu_7O_(14.3)的化学键参数计算

使用复杂晶体上化学键理论计算了 RBa2 Cu4 O8(R=Dy,Ho,Er,Tm ,Yb)和 Y2 Ba4 Cu7O14 .3 的化学键参数 .结果表明 ,Cu O链上的 Cu O键共价性大于它们在 Cu O2 面的共价性 .当金属元素与氧形成五配位时 ,其共价性的数值大于这些元素在六配位时的情形

The reduction of RE3+ in SrB6O10 prepared in air and the luminescence of SrB6O10 : RE2+ (RE=Eu, Sm, Tm)

The reduction of RE3+ to RE2+ (RE=Eu, Sm and Tm) in SrB6O10 prepared in air by high-temperature solid state reaction was observed. The luminescent properties of Eu2+ and Tm2+ show f-d transition and Sm2+ shows f-f transition at room temperature. Three crystallographic sites for Sm2+ in matrix are available. Vibronic transition of D-5(0)-F-7(0) of Sm2+ was studied. The coupled phonon energy about 108 cm(-1), was determined: from the vibronic transition. Due to the thermal population from D-5(0) level, (D1-FJ)-D-5-F-7 (J=0, 1, 2) transitions of Sm2+ were observed at room temperature. A charge compensation mechanism is proposed as a possible explanation.

Bond covalencies in R2BaCuO5 (R = Sm, Gd, Dy, Ho, Y, Er, Tm, Yb, Lu)

Bond covalencies in R2BaCuO5 (R = Sm, Gd, Dy, Ho, Y, Er, Tm, Yb, Lu) were calculated by means of a semiempirical method. This method is the generalization of the dielectric description theory of Phillips-Van Vechten-Levine-Tanaka scheme. The present paper presents the formula concerning the decomposing of complex crystals which are usually anisotropic systems into the sum of binary crystals which are isotropic systems. It can be seen that although the bond covalency is related to many physical quantities, it is mainly influenced by bond valence or bond charge, and a higher bond valence will produce higher bond covalency.

PA1010/66共聚物红外光谱研究

用红外光谱法研究了Pa1010/66共聚物氢键含量、N-H键伸缩振动力常数分布与组成的关系，发现66盐重量含量为40%时氢键含量最低，N-H伸缩振动力常数分布最宽，解释了PA1010/66共聚物热力学、结晶、机械等性能随组成改变而变化的原因.

尼龙1010/6及尼龙1010/66基本物理性能与组成的关系

尼龙1010/6 和尼龙1010/66 的基本物理性能随着组成的改变而改变,尼龙1010 含量高时,共聚物密度大于计算值;含量低时,共聚物密度小于计算值.尼龙1010 含量20%左右时,共聚物具有较大吸水率

Crystallization and melting behavior of nylon 66 poly(ether imide) blends

Isothermal crystallization and melting behavior of nylon 66 and its blends with poly(ether imide) (PEI) were investigated by differential scanning calorimetry. Crystallization kinetics such as overall rate constant Z and index n were calculated according to Avrami approach. Crystallization in the blend was retarded with respect to that of pure nylon 66 by incorporation of PEI with high glass transition temperature (T-g). The lowest growth rate of the spherulites was observed in the blends containing 10 and 15 wt% fraction of PEI. A transition temperature where positively birefringent spherulites disappear and negative birefringent spherulites develop was measured by thermal analysis. The transition temperature increased with content of PEI in the blends. A suitable range of isothermally crystallization temperatures, 238.5-246 degrees C, is suggested For determining the equilibrium melting points by means of Hoffman-Weeks approach.

Tremolite-reinforced nylon 66 composites: Mechanical and rheological properties

The reinforcement effect of an acicular inorganic filler, tremolite, on nylon 66 was studied. The mechanical properties of tremolite-filled nylon 66 composites and the effect of the filler particle size on them were obtained. The dynamic mechanical properties and rheological properties of the composites were measured. Two treatments, silane and unsaturated polyester, were used to improve the interface between tremolite and the nylon matrix. The morphologies of the composites were investigated using SEM. (C) 1998 John Wiley & Sons, Inc.

The bond ionicity in RBa2Cu3O7 (R=Pr, Sm, Eu, Gd, Dy, Y, Ho, Er, Tm)

RBa2Cu3O7 (R = Pr, Sm, Eu, Gd, Dy, Y, Ho, Er, Tm) has been studied using complex chemical bond theory. The results indicated that with the decreasing of R radius, the ionicities for all considered types of bond decrease. This is in good agreement with the experimental fact that T-c decreases with the decreasing of R radius. PrBa2Cu3O7 with no Ba-site Pr in this calculation is also predicted to be a superconductor. This supports the conclusion obtained by Blackstead et al. The ionicity for each bond obeys the following order: Ba-O > R-O > Cu(2)-O(1) > Cu(2)-O(2,3) > Cu(1)-O(4) similar to Cu(1)-O(1).

A novel rare earth coordination catalyst for polymerization of biodegradable aliphatic lactones and lactides

A novel rare earth coordination system composed of lanthanide trifluoroacetates Ln(CF3COO)(3) (Ln = Y, Yb, Nd, Tm, Ho, La, Pr) and triisobutylaluminium Al(i-Bu)(3) was used as catalyst for the polymerization of epsilon-caprolactone (CL), D,L-lactide (DLLA) and their copolymerization. The influence of temperature, time and catalyst concentration on polymerization yields and molecular weights of the polyesters have been studied. It was shown that the ring-opening polymerization of cyclic esters catalysed by Ln(CF3COO)(3)/Al(i-Bu)(3) has some living character and the molecular weight of the polyester could be controlled by adjusting the molar ratio of monomer to catalyst. The DLLA/CL copolymer was synthesized by sequential addition of monomers and the structure of the copolyester was characterized by GPC, NMR and DSC. (C) 1998 SCI.

LiMgAlF_6 : Tm~(3+) 的合成与光谱特性

采用高温固相反应法，ＬｉＦ／ＭｇＦ２／ＡｌＦ３＝１２０／１１０／１００，烧结温度为１００８Ｋ，烧结时间为４ｈ，在流动的高纯Ａｒ中合成了ＬｉＭｇＡｌＦ６：Ｔｍ３＋。对其结构和发光特性进行了研究。

辐射交联型PA－66机械物理性能研究

本文讨论了进口与国产ＰＡ—６６经钴源辐射交联后，对机械物理性能产生的影响。发现适量经辐射的ＰＡ—６６球压硬度、拉伸强度、Ｉｚｏｄ冲击强度都有较大幅度提高，并在１００，０００Ｇｙ剂量对达最大值，而断裂伸长率在１００，０００Ｇｙ剂量以下变化不大。国产ＰＡ—６６辐射后在乙二醇中，在２５０℃时，２小时不起层，性能变化不大，可替代进口材料。

MORPHOLOGY AND DYNAMIC-MECHANICAL PROPERTIES OF NYLON 66/POLY(ETHER IMIDE) BLENDS

The morphology and dynamic mechanical properties of blends of poly(ether imide) (PEI) and nylon 66 over the full composition range have been investigated. Torque changes during mixing were also measured. Lower torque values than those calculated by the log-additivity rule were obtained, resulting from the slip at the interface due to low interaction between the components. The particle size of the dispersed phase and morphology of the blends were examined by scanning electron microscopy. The composition of each phase was calculated. The blends of PEI and nylon 66 showed phase-separated structures with small spherical domains of 0.3 similar to 0.7 mu m. The glass transition temperatures (T(g)s) of the blends were shifted inward, compared with those of the homopolymers, which implied that the blends were partially miscible over a range of compositions. T-g1, corresponding to PEI-rich phase, was less affected by composition than T-g2, corresponding to nylon 66-rich phase. This indicated that the fraction of PEI mixed into nylon 66-rich phase increased with decreasing PEI content and that nylon 66 was rarely mixed into the PEI-rich phase. The effect of composition on the secondary relaxations was examined. Both T-beta, corresponding to the motion of amide groups in nylon 66, and T-gamma, corresponding to that of ether groups in PEI, were shifted to higher temperature, probably because of the formation of intermolecular interactions between the components.

硅灰石填充尼龙66的力学性能

硅灰石填充尼龙６６的力学性能王雪芹，李滨耀（中国科学院长春应用化学研究所长春１３００２２）关键词硅灰石，尼龙６６，填充改性，力学性能硅灰石是一种工业矿物，具有完整的短纤维针状结构，在塑料的填充改性中，能够与石棉、滑石、云母等相媲美，在欧美占无机填料市...

YP_5O_(14):Er~(3+),Tm~(3+)晶体的合成

研究了水热法合成晶体,浓度配比、生长温度对晶体生长习性的影响.合成了一系列化学计量比的Y_(1-x-0.3)Er_(0.3)Tm_xP_5O_(14)(x=0.01～0.1)晶体,观察和分析了晶体的缺陷及成因,测定和讨论了晶体结构.

基于GIS探讨人类活动和坡度对藏羚生境的影响

以3S技术为手段，研究了藏羚在青海最主要分布区曲麻莱、治多和可可西里境内藏羚生境状况及其坡度、道路、和居民点对藏羚生境的影响。通过野外考察基本掌握了藏羚的生境的基本特征，取得了考察路线附近区域内藏羚分布的GPS数据及其具有对应的数量、地形地貌、生境类型、人类活动状况等属性数据的藏羚分布点图层。对研究地区LANDSAT TM / ETM+ 5（红）、4（绿）、3（蓝）波段组合影像进行非监督分类，共分出水体和裸岩、沼泽地、沙地、砾石地、低草地、中草地和高草地7种生境类型，将藏羚生境适宜等级划分为不适宜、较差、适宜和非常适宜，其中适宜等级和非常适宜等级的生境类型为藏羚适宜的生境。 首先，将藏羚分布点图层分别和遥感影像假彩色合成图像、坡度图层、道路图层、居民点图层进行叠加分析、距离查询等分析了遥感影像非监督分类的判图依据，设立了坡度、道路、居民点对藏羚生境影响强度的评价原则。然后，通过对研究地区遥感影像进行非监督分类分析研究了藏羚不同适宜程度的生境面积。通过坡度分析和地图查询分析研究了坡度对藏羚生境的影响。通过缓冲区分析研究了道路和居民点对藏羚生境的影响。最后将坡度、道路和居民点三个因素结合起来通过地图综合查询分析研究了这三个因素对藏羚生境的综合影响，并给出了研究地区藏羚不同适宜等级的生境面积。 主要的研究结果和结论如下： 1、从不同类型生境在研究地区中所占比例的趋势上看，治多地区和曲麻莱地区的植被要明显优于可可西里地区，这与整个研究地区从西北到东南地势逐渐降低、水热条件逐渐变好的趋势相一致，至少可以说，从食物条件来看，治多地区和曲麻莱地区比可可西里地区更适于藏羚的栖息。 在曲麻莱地区藏羚的潜在生境面积共26861 km2，占该地区总面积的69%；在治多地区藏羚的潜在生境面积共21617 km2，占该地区总面积的68%；在可可西里地区藏羚的潜在生境面积共26398 km2，占该地区总面积的54%。 2、根据藏羚分布点图层与坡度分析图层的地图查询分析，把藏羚的生境按坡度分为2类，坡度小于等于30度时为适宜生境，坡度大于30度时为不适宜生境。将研究地区坡度栅格图像（grid文件）和非监督分类结果栅格图像（grid文件）进行地图查询分析，结果表明，在整个研究地区坡度大于30度的生境面积所占的比例不到总面积的3%，坡度影响下研究地区藏羚适宜栖息的生境面积变化不大。考虑到坡度的影响，曲麻莱、治多和可可西里适合藏羚栖息的面积分别为26663 km2（68%）、21187 km2（66%）和26350 km2（54%）。 3、根据最近原则连接藏羚分布点图层与道路图层空间数据，通过Distance综合查询分析，把道路对藏羚的影响程度划分为4个等级：距离道路0－1000m，强烈影响；距离道路1000－2000m，中度影响；距离道路2000－3000m，轻度影响；距离道3000m以外，无影响。然后在ArcView GIS 3.2a软件环境的支持下对研究地区的道路图层分别做距离道路为1000m、2000m和3000m的缓冲区分析研究，则曲麻莱、治多和可可西里地区藏羚生境受道路累计影响的面积及其分别占各研究地区总面积的比例分别为20215 km2（51.80%）、19480 km2（61%）和4437 km2（9 %）。考虑道路对藏羚生境的影响，在治多和曲麻莱地区，由于道路的影响将使得藏羚生境大面积丧失，生境高度破碎化。 4、根据最近原则连接藏羚分布点图层与居民点图层空间数据，通过Distance综合查询分析，把居民点对藏羚的影响程度划分为4个等级：距离居民点0－3000m，强烈影响；距离居民点3000－6000m，中度影响；距离居民点6000－9000m，轻度影响；距离居民点9000m以外，无影响。然后在ArcView GIS 3.2a软件环境的支持下对研究地区的居民点图层分别做距离居民点距离为3000m、6000m和9000m的缓冲区分析。曲麻莱、治多和可可西里地区藏羚生境受居民点影响的面积及其分别占总面积的比例分别为11282 km2（29%）、15258 km2（48%）和3846 km2（8%）。从居民点对藏羚生境的影响看，由于居民点的影响使得治多和曲麻莱地区，尤其是治多地区，藏羚生境大面积丧失，生境高度破碎化。 5、人类活动（主要是道路和居民点）对藏羚生境适宜生境面积的影响是研究中主要的内容，鉴于道路和居民点对藏羚生境影响的评价原则分类方法一致，我们把道路和居民点对藏羚的影响程度合并为4个等级（距离道路0－1000m内或距离居民点0－3000m内，强烈影响；距离道路1000－2000m内或距离居民点3000－6000m内，中度影响；距离道路2000－3000m内或距离居民点6000－9000m内，轻度影响；距离道路3000m以外或距离居民点9000m以外，无影响，对道路和居民点相应距离的缓冲区分析图层进行合并等操作，测定曲麻莱、治多和可可西里地区藏羚生境受人类活动影响的面积及其占总面积的比例分别为21595 km2（55%）、22271 km2（70%）和4775 km2（10%）。 在治多和曲麻莱地区，由于人类活动的影响使得藏羚生境大面积丧失，生境高度破碎化，尤其是治多地区，影响面积达将近70%。在可可西里地区，10%的影响面积虽然不是太大，但是近几年来由于各种形式的旅游日趋升温，尤其是青藏铁路建设开通，将增加道路对藏羚生境的影响程度。人类活动影响在研究地区分布极不平均，在曲麻莱的中东部、治多的东部以及可可西里的109国道附近人类活动影响的强度较大，在这些地区藏羚的生存条件恶劣，甚至部分地区已经不适合藏羚栖息了。 6、最后，基于研究地区的坡度grid图层、非监督分类grid图层以及不同程度人类活动影响的grid图层，对不同坡度、道路和居民影响的生境面积进行综合查询分析。把人类活动对藏羚生境的影响强度重新划分为如下3个等级，A、短距离影响，距离道路1000m或距离居民点3000m范围内的影响，也就是人类活动的强烈影响；B、中距离影响，距离道路2000m或距离居民点6000m范围内的影响，也就是人类活动的强烈影响和中度影响之和；C、长距离影响，距离道路3000m或距离居民点9000m范围内的影响，也就是人类活动的强烈影响、中度影响和轻度影响的总和。曲麻莱、治多和可可西里研究地区中坡度小于等于30度并且人类活动长距离范围影响下藏羚适合栖息的生境面积及占相应研究地区总面积的比例为12597 km2（32%）、6117km2（19%）和23564km2（48%）。 在研究地区，治多地区人类活动对藏羚生境适宜性的影响最为严重，其次为曲麻莱地区，而可可西里地区的人类活动影响较小。尤其是治多地区和曲麻莱地区，当人类活动的影响最大距离时，治多地区藏羚适宜生境面积竟然不到总面积的1/5，曲麻莱地区不到1/3。这两地区人类活动主要集中在东部，导致治多东部地区和曲麻莱中东部地区几乎没有藏羚分布。于是，由于人类活动的影响，使得拥有良好生境条件的治多和曲麻莱地区适合藏羚栖息的生境却较少，而生境条件相对较差的可可西里地区反而拥有相对较多的适合藏羚栖息的生境。