Y1-xNdxSr2Cu2.7Mo0.3O7-δ体系的声子振动谱和输运性质

研究了Y_1-xNd_xSr₂Cu_2.7Mo_0.3O_7-δ(x =0 ,0 .1 ,0 .2 ,0 .5 ,0 .8和 1 .0 )的Ra-man光谱、红外光谱,指出RSr₂Cu_2.7Mo_0.3 O_7-δ结构上与RBa₂Cu₃O_7-δ有显著的差异,而伴随着Nd的掺入,晶体的微结构发生了变化 .结合电阻率和热电势的测量结果 ,我们讨论了这种微结构变化对载流子分布的影响和NdSr₂Cu_2.7Mo_0.3O_7-δ不超导的原因,进而指出在高温超导体中广泛存在的稀土离子尺寸效应也是大稀土离子替代产生的晶体微结构变化的结果     

OPTIMUM DURATION OF MEASUREMENT FOR REDUCING THERMAL NOISE LIMITATIONS IN TORSION PENDULUM EXPERIMENTS

Statistical estimates of thermal noise fluctuation of a linear harmonic oscillator used to detect weak forces are reexamined with special reference to gravitational experiments. Thermal noise limitation on the measurement of displacement of an oscillator is studied. It is found that the signal response of an oscillator reaches the maximum value while the thermal noise response reaches the minimum value at the same time during the transient state of the oscillator, and the precision of the experiments in the transient state could increase about two orders higher than that in the equilibrium state for typical experiments. It is also found that there is an optimum duration of measurement in which the uncertainty due to thermal noise in this period is the least.     

TRANSFORMATION OF CULTURED HUMAN FETAL GASTRIC FIBROBLASTS WITH PHYSICO-CHEMICAL AGENTS

Treatment of early passage human fetal gastric fibrohlasts with ultraviolet (UV) light and the chemical carcinogen ethyl nitrosourea (ENU) in succession resulted in an immortally growing cell line, named GTS 8502. The cells of this line display typical transformation characteristics, such as irregularly shaped nuclei, heteroploidization of karyotype and frequent appearance of heteromorphic chromosomes, the enhanced volume ratio of nucleus to cytoplasm, multinucleoli, appearance of microvilli on the surface of the cells and agglutination reaction to lectin concanavalin A. The transformants have high growing and mitotic indices and the ability of focus-formation on monolayers and anchorage independent growth in soft agar medium. Moreover, these cells induced turnouts in nude mice or in immunosuppressed new-born rats through heterotransplantation. The results of various methods including electromicroscopy and histochemical analyses indicate that GTS 8502 cells are of fibroblast origin.Our results thus indi     

L12结构:组元的原子半径及晶胞常数

本文给出了一套L1₂化合物的原子半径。考虑到作为基组元和非基组元的原子在L1₂结构内配位细节的不同,所受到的影响和作用也不一样,因此,作为决定化合物晶胞大小的原子半径亦不相同,这样分别给出了非基组元的原子半径r_A和基组元的原子半径r_B;并给出了用这套半径来计算L1₂化合物晶胞常数的公式:α=(√2(r_A+r_B);对158个L1₂化合物的晶胞常数作了计算和讨论,大多数化合物计算值对实验结果的偏离都少于0.01。     

非平衡超导铅膜中的非均匀能隙态

用两个重叠的铅隧道结进行实验,当注入电流很大时在铅膜中观察到了非均匀能隙态,铅膜中出现非均匀态的功率阈值比铝膜大得多。 关键词：     

相转移催化合成苯基烷氧羰基甲基次膦酸酯和二苯基烷氧羰基甲基氧化叔膦

液-液相转移催化 P-烷基化反应的研究工作还不多。Kem 等曾用亚磷酸二烷基酯或二烷基氧化膦与氯代的取代乙酰胺通过液-液相转移法合成了取代胺基羰基与甲基膦酸酯及氧化叔膦。我们曾研究了亚膦酸二烷基酯与氯     

“磁氢原子”的光谱

对于以荷正电的磁单极子为核的原子(简称“磁氢原子”),本文计算了它的能级、选择规则、跃迁几率、光谱和谱线强度。其中三条特征吸收谱线(2774?,2734?,2191?)的相对强度是37:50:6。 关键词：     

用直接法测定晶体的超结构

在许多无机物(包括矿物和一些重要的固体材料)的晶体中,往往形成所谓“超结构”。反映超结构细节的所谓“超结构衍射点”,其强度通常都很弱。因此,在测定这类晶体结构时,一般都先将超结构点略去以求出一个只反映概貌的“赝结构”。然后在此基础上再探寻超结构的细节。但是,用普通的结构修正办法不可能从赝结构直接解出超结构。这就增加了超结构分析的困难。本文提出从赝结构衍射相角推引超结构衍射相角,借以简化超结构的分析过程。试验表明,这一方法是有效的。 关键词：