海藻酸钠溶液溶胶—凝胶相转移的温度效应及IR光谱研究

考察了３ｗｔ％海藻酸钠溶液中加入Ｃｕ＾２＾＋，Ｃ０＾２＾＋后，体系的粘度，电导与离子浓度，温度的关系，结合ＩＲ光谱对海藻酸钠溶液在溶胶－凝胶相转移过程中的分子结构与构型变化进行了解剖。     

褐藻酸钠对Cu2+、Pb2+交换与吸附性能的研究

本文研究了褐藻酸钠与Ｃｕ＾２＋,Ｐｂ＾２＋交换行为,通过海藻酸钠溶液与Ｃｕ＾２＋,Ｐｂ＾２＋的絮凝,测得两种离子最大交换量。考察了褐藻酸钠固体粉末与Ｃｕ＾２＋,Ｐｂ＾２＋在不同的反应条件下的离子交换与吸附行为。实验表明ｐＨ值,温度,时间,配比等条件是影响交换与吸附的因素,其吸附行为在一定的温度和一定的浓度范围内能较好的符合Ｆｒｅｕｎｄｌｉｃｈ等温吸附式。     

发酵废渣黑根霉菌对Pb^2＋的吸附作用

本文研究了发酵废渣黑根霉菌对Ｐｂ＾２＋的吸附作用，结果表明，发酵废渣黑根霉菌对Ｐｂ＾２＋有较好的吸附能力，在ｐＨ３～６．５范围内，吸附能力最强。用海藻酸钠将粉末状黑根霉菌包埋成形后，机械性能较好，流速对动态吸附有很大影响，当流速为０．２７５ＢＶ／ｍｉｎ时，吸附率达８３．６％，饱和吸附量可达４９ｍｇ／ｇ。用２０％ＣａＣｌ２溶液可以洗脱和再生。本文研究结果为发酵废渣黑根霉菌的工业应用提供了基础数据。     

溶液pH值,配体及重金属离子Hg^2＋,Cd^2＋,Pb^2＋对细胞色素C电化学活性的影

本文研究溶液ｐＨ值，配体及某些重金属离子对细胞色素Ｃ电化学活性的影响。实验发现：在ｐＨ＝２．０和ｐＨ＝１０．０的磷酸盐缓冲溶液中，细胞色素Ｃ失活，用强的配体ＣＮ＾－与铁卟啉发生配位取代反应虽使溶液相中的细胞色素Ｃ失活，但不影响吸附态的细胞色素Ｃ的活性；重金属离子Ｈｇ＾２＋，Ｃｄ＾２＋，Ｐｂ＾２＋对细胞色素Ｃ电化学活性影响的程度不同，影响大小的顺序为Ｈｇ＾２＋〉Ｃｄ＾２＋〉Ｐｂ＾２＋并对可能的机理进     

四元交互体系Li~＋，K~＋／Cl~－，SO_4~（2－）－H_2O50，7

采用等温溶解平衡法测定了四元交互体系Ｌｉ～＋，Ｋ～＋／Ｃｌ～－，７５℃的溶解度和平衡溶液的物化性质（密度、粘度、折光率）．该四元交互体系５０，７５℃的溶解度等温图有５个相区：即Ｌｉ＿２ＳＯ＿４·Ｈ＿２Ｏ，ＫＬｉＳＯ＿４，ＫＣｌ，Ｋ＿２ＳＯ＿４，ＬｉＣｌ·Ｈ＿２Ｏ，７条单变量曲线，３个共饱点，其中Ｌｉ＿２Ｏ＿４·Ｈ）２Ｏ＋ＫＣｌ＋ＬｉＣｌ·Ｈ＿２Ｏ为一致零变量点。用我们以往提出的经验公式处理了平衡溶液的密度和折光率，由所测得的溶解度数据，求得了高温和高锂浓度下的电解质溶液Ｐｉｔｚｅｒ模型的离子相互作用参数。计算了各平衡溶液中盐的活度和水的活度。还计算了该四元交互体系２５℃的溶解度，考察了Ｐｉｔｚｅｒ电解质溶液理论在水－盐溶解度计算中的应用。     

硫酸铵存在下碘化物—结晶紫—丙醇体系萃取分离镉

研究了硫酸铵存在下，碘化物－结晶紫－丙醇体系萃取镉的行为以及丙醇水溶液的分相条件，试验表明，丙醇作为萃取溶剂，能萃取中性离子缔合物，调节溶液ｐＨ＝１．０或ｐＨ＝４．０，该体系使能Ｃｄ＾２＋，从常见过渡元素Ｆｅ＾３＋，Ｃｏ＾２＋，Ｎｉ＾２＋，Ｍｎ＾２＋，Ｚｎ＾２＋，Ｃｒ＾３＋的混合液中分离出来。     

微晶萘固相萃取分离富集及ICP—AES测定Cu,Mn的研究

报道以微晶萘作吸附载体的固相萃取分离及ＩＣＰ－ＡＥＳ测定Ｃｕ，Ｍｎ的新方法，详细研究了溶液酸度，试剂浓度，萘用量及共存离子对待测物回收率的影响，考查了加入适量的Ｃｏ＾２＋，对富集痕量Ｃｕ＾２＋Ｍｎ＾２＋辅助作用，本法用于生物样品马尾藻及小牛肝中Ｃｕ，Ｍｎ的测定，分析结果与标准值吻合。     

氨三乙酸稀土络合物配体交换反应的NMR研究

利用变温＾１３Ｃ，＾１Ｈ－ＮＭＲ研究了过量配体存在下，氨三乙酸稀土络合物Ｌｎ（ＮＴＡ）２（Ｌｎ＝Ｃｅ，Ｐｒ和Ｎｄ）配体交换反应。在中必不溶液中，分子间的配体交换过程按中下机制进行：Ｌｎ（ＮＴＡ）２＾３－＋ＨＮＴＡ＾２－＝Ｌｎ（ＮＴＡ）（ＮＴＡ）＾３＋＋ＮＨＴＡ＾２－由溶液中溶液中自由ＮＴＡ信号线宽分析了交换速率、确定了反应的活化能。结果表明，分子间配体交换反应化能与相应稀土络合物热力学稳定性有一定     

倒数示波计时电位法在合金样品测定中的应用

应用倒数示波计时电位法，在含有吸附络合物的溶液中，采用桂汞电极作为极化电极，测定了Ｃｕ＾２＋、Ｎｉ＾２＋、Ｃｄ＾２＋、Ｐｂ＾２＋等几种金属离子的检测下限，并通过沿（ｄＥ／ｄｔ）－１￣Ｅ曲线上的峰高对合金样品进行定量分析，得到满意结果。实现了示波分析由常量到微量的飞跃。     

氮杂冠醚研究X．双偶氮基开链有色冠醚与过渡金属离子选择配位作用的研究

本文研究了双偶氮基开链有色冠醚１和２与过渡金属离子反应后的紫外可见光谱。实验结果表明：化合物１对Ａｇ￣＋Ｒｄ￣２＋、Ｐｔ￣４＋、Ｎｉ￣２＋和Ｃｒ￣２＋，化合物２对Ｐｄ￣２＋和Ｐｔ￣４＋有明显的选择配位作用，其中２对Ｌｉ￣＋生成配合物时△λ＿（ｍａｘ）很大（１０５ｎｍ），溶液有根明显的变色现象，故２可能用作Ｌｉ￣＋的分光光度显色剂。     

Visible‐Light Photoredox Catalysis Enables the Biomimetic Synthesis of Nyingchinoids A,B, and D,and Rasumatranin D

The total synthesis of nyingchinoids A and B has been achieved through successive rearrangements of a 1,2‐dioxane intermediate that was assembled using a visible‐light photoredox‐catalysed aerobic [2+2+2] cycloaddition. Nyingchinoid D was synthesised with a competing [2+2] cycloaddition. Based on NMR data and biosynthetic speculation, we proposed a structure revision of the related natural product rasumatranin D, which was confirmed through total synthesis. Under photoredox conditions, we observed the conversion of a cyclobutane into a 1,2‐dioxane through retro‐[2+2] cycloaddition followed by aerobic [2+2+2] cycloaddition.     

Visible‐Light Photoredox Catalysis Enables the Biomimetic Synthesis of Nyingchinoids A,B, and D,and Rasumatranin D

The total synthesis of nyingchinoids A and B has been achieved through successive rearrangements of a 1,2‐dioxane intermediate that was assembled using a visible‐light photoredox‐catalysed aerobic [2+2+2] cycloaddition. Nyingchinoid D was synthesised with a competing [2+2] cycloaddition. Based on NMR data and biosynthetic speculation, we proposed a structure revision of the related natural product rasumatranin D, which was confirmed through total synthesis. Under photoredox conditions, we observed the conversion of a cyclobutane into a 1,2‐dioxane through retro‐[2+2] cycloaddition followed by aerobic [2+2+2] cycloaddition.     

Calciomics:prediction and analysis of EF-hand calcium binding proteins by protein engineering

Ca2+ plays a pivotal role in the physiology and biochemistry of prokaryotic and mammalian organisms.Viruses also utilize the universal Ca2+ signal to create a specific cellular environment to achieve coexistence with the host,and to propagate.In this paper we first describe our development of a grafting approach to understand site-specific Ca2+ binding properties of EF-hand proteins with a helix-loop-helix Ca2+ binding motif,then summarize our prediction and identification of EF-hand Ca2+ binding sites on a...     

Wavelength-dependent fragmentation and clustering observed after femtosecond laser ablation of solid C60

We report here the resonance effect in femtosecond laser ablation of solid C60 by investigating wavelength and fluence dependence of product ion species. When the ablation laser wavelength is far from the molecular absorption band of C60, we observe both C60-2n+ fragment ions and C60+2n+ cluster ions as well as C60+ parent ion. Delayed ionization of C60 is not significant. When the ablation laser wavelength is near resonant with the molecular absorption, we observe C60+ and some amount of C60-2n+ fragment ions depending on the laser fluence. Delayed ionization of C60 is significant in this case, which indicates high internal energy of C60 molecule. From the observations, we confirm the strong coupling of femtosecond laser energy with C60 molecule when the molecular absorption is high at the ablation laser wavelength.     

DSB显著提高羧酸盐驱油体系抗钙镁离子能力的研究

测定了工业品级的天然混合长链烷基羧酸盐(SDC)以及与3-(N,N-二甲基十二烷基胺)-2-羟基-丙磺酸(DSB)复配驱油体系的界面张力(ITFmin), 分别得出其抗钙镁离子的能力为400和5000 mg/L. 选择试剂级十二烷基羧酸钠与DSB复配, 测定了不同配比溶液的表面张力值和临界胶束浓度cmc, 结合长链烷基脂肪酸与钙离子的溶度积Ksp, 分析了对不溶性长链烷基羧酸盐形成的影响. 根据现场驱油体系配方, 计算了两者在溶液中的摩尔配比为4:1时的十二烷基羧酸盐在胶束中的摩尔分数xm1为0.51, 相互作用参数βm值为-3.11, 反映了两者有较强的相互作用. 采用量子化学方法, 对由1个十二烷基羧酸分子、1个DSB分子及1个二价钙离子组成的模型复合物进行了能量计算和电荷分布计算, 得出在长链烷基羧酸盐和DSB两者混合胶束的界面层中存在负电荷空穴, 提出二价金属离子被络合的模型, 合理地解释了实验事实.     

Open-shell spherical aromaticity: the 2N2 + 2N + 1 (with S = N + ½) rule

4N Baird's rule represented the extension of Hückel's 4N + 2 rule to triplet state systems. In this work we extend the 2(N + 1)(2) Hirsch rule for spherical aromatic species to open-shell spherical compounds and we provide evidence that those spherical species having a same-spin half-filled last energy level with the rest of the levels being fully-filled, i.e., those having 2N(2) + 2N + 1 electrons and S = N + ?, are aromatic.     

Thermal rate constant calculation of the NF + F reactive system multiple arrangements

In this work we analyzed the multiple channels of the reaction NF+F through the evaluation of thermal rate constants with both Wigner and Eckart tunneling corrections. Minimum energy paths and intrinsic reaction coordinates of the systems were obtained and accurately studied in order to ensure the consistency of our results. Specifically, we investigated the NF + F = N + F(2), NF + F = NF + F, and NF(2) = NF + F, reactive systems. As experimental data are available for the latter reaction, we were able to conclude that our thermal rate constants are in agreement for a wide range of temperatures. The here performed study is relevant to the understanding of the decomposition process of nitrogen trifluoride (NF(3)).     

Identification of iron(III) peroxo species in the active site of the superoxide reductase SOR from Desulfoarculus baarsii

The active site of superoxide reductase SOR consists of an Fe2+ center in an unusual [His4 Cys1] square-pyramidal geometry. It specifically reduces superoxide to produce H2O2. Here, we have reacted the SOR from Desulfoarculus baarsii directly with H2O2. We have found that its active site can transiently stabilize an Fe3+-peroxo species that we have spectroscopically characterized by resonance Raman. The mutation of the strictly conserved Glu47 into alanine results in a stabilization of this Fe3+-peroxo species, when compared to the wild-type form. These data support the hypothesis that the reaction of SOR proceeds through such a Fe3+-peroxo intermediate. This also suggests that Glu47 might serve to help H2O2 release during the reaction with superoxide.     

Ca-Mediated Synthetic Biosystems Offer Protein Design Versatility, Signal Specificity, and Pathway Rewiring

Synthetic biosystems have been engineered that enable control of metazoan cell morphology, migration, and death. These systems possess signal specificity, but lack flexibility of input signal. To exploit the potential of Ca²⁺ signaling, we designed RhoA chimeras for reversible, Ca²⁺-dependent control over RhoA morphology and migration. First, we inserted a calmodulin-binding peptide into a RhoA loop that activates or deactivates RhoA in response to Ca²⁺ signals depending on the chosen peptide. Second, we localized the Ca²⁺-activated RhoA chimera to the plasma membrane, where it responded specifically to local Ca²⁺ signals. Third, input control of RhoA morphology was rewired by coexpressing the Ca²⁺-activated RhoA chimera with Ca²⁺-transport proteins using acetylcholine, store-operated Ca²⁺ entry, and blue light. Engineering synthetic biological systems with input versatility and tunable spatiotemporal responses motivates further application of Ca²⁺ signaling in this field.     

Effect of Coriolis coupling in chemical reaction dynamics

It is essential to evaluate the role of Coriolis coupling effect in molecular reaction dynamics. Here we consider Coriolis coupling effect in quantum reactive scattering calculations in the context of both adiabaticity and nonadiabaticity, with particular emphasis on examining the role of Coriolis coupling effect in reaction dynamics of triatomic molecular systems. We present the results of our own calculations by the time-dependent quantum wave packet approach for H + D2 and F(2P3/2,2P1/2) + H2 as well as for the ion-molecule collisions of He + H2 +, D(-) + H2, H(-) + D2, and D+ + H2, after reviewing in detail other related research efforts on this issue.