铂电极上异黄樟油和胡椒醛电氧化的SERS研究

采用循环伏安(CV)法和原位表面增强拉曼光谱(SERS)技术, 研究了非水体系中反应物异黄樟油和目标产物胡椒醛在粗糙铂电极上的电氧化行为, 发现胡椒醛在电位≥1.50 V时将进一步氧化, 而且从分子水平证实, 在胡椒醛的氧化电位(≥1.50 V) 下, 波长为632.8 nm的激光对胡椒醛的氧化有助催化作用. 由异黄樟油直接电氧化合成胡椒醛的电位(E)应控制在1.20 V相似文献   

AlF3包覆天然石墨负极材料的制备及其电化学性能

以天然石墨为原料,通过机械高速分散设备将天然石墨和AlF₃在液相介质中充分混合,混合液喷雾干燥后获得颗粒形态均匀分散的AlF₃包覆天然石墨（NG）复合负极材料（AF/NG）。一方面AlF₃包覆层有助于在天然石墨表面形成稳定的SEI膜,提升材料的循环稳定性;另一方面AlF₃的引入改善了锂离子在天然石墨内外的迁移与扩散,提升复合材料的倍率性能,0.5C倍率下放电比容量达到278 mAh·g^-1,同等倍率下比未包覆AlF₃样品提高了78 mAh·g^-1。合成工艺简单易管控,适合规模化商业生产。     

Two new hydrogen bond-supported supramolecular compounds assembly from polyoxovanadate and organoamines

Two novel organic-inorganic hybrid compounds based on organoamines and polyoxovanadates formulated as (H₂dien)₄[H₁₀V₁₈O₄₂(PO₄)](PO₄)·2H₂O (1) (dien=diethylenetriamine) and (Him)₈[HV₁₈O₄₂(PO₄)] (2) (im=imidazole) have been prepared under hydrothermal conditions by using different starting materials, and characterized by elemental analyses, IR, ESR, XPS, TGA and single-crystal X-ray diffraction analyses. Crystal data for compound 1: C₁₆H₇₄N₁₂O₅₂V₁₈P₂, Monoclinic, space group C2/c, a=23.9593(4) Å, b=13.0098(2) Å, c=20.1703(4) Å, β=105.566(3)°, V=6056.6(19) Å³, Z=4; for compound 2, C₂₄H₄₁N₁₆O₄₆V₁₈P, Tetragonal, space group I4/mmm, a=13.5154(8) Å, b=13.5154(8) Å, c=19.1136 Å, β=90°, V=3491.4(3) Å³, Z=2. Compound 1 consists of protonated diens together with polyoxovanadates [H₁₀V₁₈O₄₂(PO₄)]⁵⁻. Compound 2 is composed of protonated ims and polyoxovanadates [HV₁₈O₄₂(PO₄)]⁸⁻. There are hydrogen-bonding interactions between polyoxovanadates and different organoamines in 1 and 2. Polyoxovanadates are linked through H₂dien into a three-dimensional network via hydrogen bonds in 1, while polyoxovanadates are linked by Him into a two-dimensional layer network via hydrogen bonds in 2. The crystal packing patterns of the two compounds reveal various supramolecular frameworks.     

A DFT Study on the Stable Structures and Dissociation Mechanism of C3O6 Cluster

Using geometrical optimization and DFT method at the B3LYP/6-31G (d) level, nineteen equilibrium geometries were identified, and three transition states of dissociation reaction of C3O6 clusters were also found. The vibrational frequencies and intrinsic reaction coordinate (IRC) verification at the same level were computed to verify the transitions. And then we calculated the dissociation energies and analyzed the dissociation channels. The computational results show that the dissociation energies of C3O6 isomers relative to three CO2 are between 1.509 × 103 and 10.61 × 103 kJ·kg-1, and the energy barriers of the reactions are 92.857, 131.138 and 185.793 kJ·mol-1. Both the high dissociation energies and high energy barriers show that C3O6 clusters studied in this paper are stable enough to be used as high-energy-density materials.     

Hydrothermal syntheses and structure characteristics of two new supramolecular compounds assembled from octamolybdates and bpy units (bpy = 4,4′-bipyridine)

Two new compounds, (Hbpy)₃(bpy)₂[K(Mo₈O₂₆)]·2H₂O (1) and H₃(bpy)₅[K(Mo₈O₂₆)]·H₂O(2) (bpy = 4,4′-bipyridine) have been synthesized under hydrothermal condition by using nearly the same starting materials, and characterized by elemental analyses, IR, TGA, XPS and single crystal X-ray diffractions. The crystal structure analyses reveal that the two compounds possess unusual networks constructed from octamolybdates, potassium ions and organic groups. Both 1 and 2 consist of an identical inorganic chain , and they have analogous structures to each other with slightly different packing modes of the organic groups and water molecules and exhibit unusual three-dimensional (3D) supramolecular networks through extensive multi-point C–HO and N–HO hydrogen-bonding interactions.     

Curie温度附近稀磁半导体(Ga,Mn)As的电学噪声谱性质

建立了自发噪声谱测量系统来研究稀磁半导体（Ga,Mn）As的电学噪声性质.通过测量（Ga,Mn）As材料的自发噪声谱,发现（Ga,Mn）As的自发涨落会随温度升高而逐渐增大,同时,外加磁场会降低（Ga,Mn）As的自发涨落,这来源于外加磁场导致的（Ga,Mn）As磁畴部分有序化.此外,不同频率的噪声随温度的变化规律有很大差异：当频率低于30 kHz的时候,噪声谱和温度的变化关系和热噪声很相似,但数值上明显大于热噪声的值;当频率在30 kHz左右的时候,噪声大小和温度成线性关系;当频率大于30 kHz以后,在相变点附近噪声大小和温度的关系出现了明显的转折,高频高温噪声的大小和热噪声的理论值非常接近.这些结果有助于深入理解（Ga,Mn）As磁性起源的物理机制. 关键词： 自旋电子学 稀磁半导体 自发涨落谱     

褐煤颗粒表面官能团的分布特征

采用原位傅里叶红外光谱漫反射测试了北皂褐煤在粒度为40—60目、60—80目、80—100目、100—160目和160目—0.1mm的官能团分布特征,对比分析了不同粒度范围内的红外测试谱图。结果表明,粒度在40—60目以后,官能团区域可识别的特征吸收峰基本一致,可识别的官能团主要是醇羟基、多元醇及缔合羟基,甲基亚甲基,不饱和醛、脂肪烃链式饱和羧酸盐、烯烃,以及苯环取代;在160目—0.1mm的粒度范围内,指纹区验证更加准确,谱图峰型峰位以及峰面积更加准确,能够满足定量分析的要求。研究成果对研究煤不同粒度的宏观特性以及红外特征的定性分析具有重要的指导作用。     

Synthesis and Micellar Behavior of DL-lactide-gelatin Copolymers as Amphiphilic and Biodegradable Materials

A series of novel biodegradable polymers, graft copolymers of D,L-lactide on gelatin, were designed and synthesized to overcome the shortcomings of gelatin and polylactide(PLA) biomaterials. The copolymers were characterized by nitrogen analysis, IR, 1H-NMR and thermal analysis. The amphiphilic properties of these copolymers were also investigated.     

AlF3包覆天然石墨负极材料的制备及其电化学性能

以天然石墨为原料,通过机械高速分散设备将天然石墨和Al F3在液相介质中充分混合,混合液喷雾干燥后获得颗粒形态均匀分散的Al F3包覆天然石墨(NG)复合负极材料(AF/NG)。一方面Al F3包覆层有助于在天然石墨表面形成稳定的SEI膜,提升材料的循环稳定性;另一方面Al F3的引入改善了锂离子在天然石墨内外的迁移与扩散,提升复合材料的倍率性能,0.5C倍率下放电比容量达到278 m Ah·g-1,同等倍率下比未包覆Al F3样品提高了78 m Ah·g-1。合成工艺简单易管控,适合规模化商业生产。     

影响反相微乳液导电性能的因素

分别以聚乙二醇辛基苯基醚(Triton X-100)或十六烷基三甲基溴化铵(CTAB)为表面活性剂, 与正己烷、正己醇和水构成反相微乳液. 研究了水相H+浓度、表面活性剂、助表面活性剂等对微乳液导电性能的影响. 结果表明, 增加水相H+浓度可大幅度提高反相微乳液的导电能力, 当H+浓度由1.0 mol•L-1增加到10 mol•L-1时, 微乳液的电导率可提高1~2个数量级. 当水相H+浓度为10 mol•L-1时, 微乳液的电导率随溶水量的增大而增大, 水油体积比为3:10时, 两种体系的电导率均达到3200 μS•cm-1. Triton X-100浓度对微乳液的电导率影响较大, 电导率随其浓度增加而增大；而CTAB浓度对微乳液电导率的影响较小, 电导率随其浓度增加略有减小；助表面活性剂正己醇使非离子型反相微乳液的电导率下降, 而使阳离子型反相微乳液的电导率先增大, 然后减小, 呈骆峰状变化.