A Study of the Probe Effect on the Apparent Image of Biological Atomic Force Microscopy

The atomic force microscopy (AFM) possesses high spatial resolution and it is compatible with liquid environments. AFM can provide possibility to study a wide range of biological problems at the molecular level and acquire topological information at nanometre resolution under physiological conditions1,2. However, a major problem for image reconstruction of biological specimens is that structures of most biological molecules are very soft and delicate, which could be easily deformed and dama…     

聚乙烯的表面光接枝改性研究进展

综述了紫外光引发接枝改性聚乙烯表面的研究进展,包括光接枝聚合机理,改性方法,接枝链的结构和形态,影响因素等。     

镧对红壤硝化、磷转化和酚分解作用的影响

通过室内培养和盆栽试验研究了La对红壤硝化作用,磷转化作用和酚分解作用的影响,低浓度下,La对土壤的硝化作用和磷转化作用均有某些刺激作用,但随着浓度的升高产生抑制作用并不断增加,La对土壤酚分解作用表现为剧烈的抑制作用,并随着浓度的升高,抑制作用不断增强,随着培养时间的延长,La对土壤硝化作用和酚分解作用的抑制作用有降低的趋势。     

O_2/EAHQ/[C_5H_5NC_(16)H_(33)]_3PW_4O_(16)体系对苯乙烯选择性催化环氧化

考察了 O2 / 2 -乙基蒽氢醌 (EAHQ) / [C5 H5 NC1 6 H33]3PW4O1 6 催化体系对苯乙烯选择性环氧化中的溶剂效应和催化剂稳定性等 .发现在邻苯二甲酸二甲酯和磷酸三丁酯的混合溶剂中 ,由于邻苯二甲酸二甲酯的配位作用较强 ,对催化剂的活性有抑制作用 ;若以甲苯取代部分邻苯二甲酸二甲酯 ,催化剂有较好的活性、较高的选择性及很好的稳定性 .当催化剂的摩尔用量从 2 -乙基蒽氢醌的 1/ 10 0减少到 1/ 80 0时 ,反应结果基本保持不变 .该体系对环氧苯乙烷的选择性达 92 % ,催化剂的转化数达 5 0 0     

Determination of constant‐volume combustion energy for the complexes of zinc nitrate with three amino acids

Five solid complexes of zinc with L‐α‐methionine, L‐α‐phenylalanine and L‐α‐histidine were prepared. The constant‐volume combustion energies of the complexes, ΔE_c (coordination), were determined by a precise rotating bomb calorimeter at 298.15 K. They were ‐ 2969.03 ± 0.34, ‐2929.46 ± 1.59, ‐9597.13 ± 6.12, ‐4378.98 ± 3.27 and ‐14047 ± 6.75 kJ/mol, respectively. Their standard enthalpies of combustion, ΔH^θ_m,c(coordination, s, 298.15 K), and standard enthalpies of formation, ΔH^θ_m,f (coordination, s, 298.15 K), were calculated. They were ‐2959.73 ± 0.34, ‐2923.88 ± 1.59, ‐9649.18 ± 6.12, ‐4373.40 ± 3.27, ‐14048.53 ± 6.75 kj/mol and ‐1180.94 ± 0.92, ‐1401.26 ± 1.77, ‐2501.69 ± 6.50, ‐1381.47 ± 3.49, ‐1950.19 ± 7.65 kJ/mol, respectively.     

Synthesis of p‐tert‐Butyl‐calix[6] ‐biscrown‐3 via Intramolecular Ring‐closure of 1,4‐Bis (2‐(2‐chloroethoxy) ethoxy) ‐p‐tert‐butyl‐calix[6]arene

With a variation in reaction conditions, 1, 4‐bis (2‐(2‐chloroethoxy)ethoxy)‐calix[6]arene (3) and l,3,5‐tris(2‐(2‐chloroethoxy) ethoxy)‐calix [6] arene (4) or 4 and 4‐chloroethoxyethoxy‐calix[6]crown‐3 (5) were selectively synthesized from p‐tert‐butyl‐calix [6] arene and 2‐(2‐chloroethoxy)ethyltosylate. l,3–4,6‐p‐tert‐butylcalix[6]‐bis‐crown‐3 (6) with (u,u,u,d,d,d) conformation and 1,3–4,5‐p‐tert‐butylcalix[6]‐biscrown‐3 (7) with self‐anchored (u,u, u, u, u, d) conformation were synthesized through an intramolecularly ring‐closing condensation of 1, 4‐bis (2‐(2‐chloroethoxy)ethoxy)‐p‐tert‐butyl‐calix[6]arene (3) in 25% and 15% yield, respectively. Using 5 instead of 3, only 7 was obtained in 65% high yield. 6 and 7 show different complexation properties toward alkali metal and ammonium ions.     

枞酸乙二醇单酯与双酯的合成工艺研究

采用L39^4正交实验研究了枞酸乙二醇单酯与双酯的合成工艺。探讨了反应温度、催化剂用量、反应物料摩尔比、反应时间等诸因素对转化率及选择性的影响。结果表明：反应温度与反应物料摩尔比分别对转化率及选择性具有最显著的影响。实验提供了枞酸乙二醇单酯与双酯的优化合成条件,在此基础上以松香为原料进行了验证。     

拟线性系统周期边值问题

The existence and uniqueness results about quasilinear periodic boundary value problems are established by using the global inverse function theorem and the result about the existence and uniquencess of periodic solutions for the periodic boundary value problem of nonhomogeneous linear periodic system.     

对应模型中微连续类在两种拓扑下的应用

本文研究了微连续子类的性质 ,证明了 :S′( X,Y)在 *一致收敛拓扑下是 Ym X的闭集 ;若 X是 P空间 ,则 S( X,Y)在图拓扑下在 Ym X中是稠密的     

导弹贮存可靠性评估

本文针对导弹上不同部件在长期贮存中、所受影响不同及可修性不同等特点 ,将弹上部件分为五类 .在此基础上、研究给出了该类导弹的贮存可靠性物理模型和相应的数学模型 ,可称作配套系统模型 ,并通过一个简单实例介绍了具体计算方法