高压拉曼光谱方法研究卟啉J-聚集体

本文利用金刚石对顶砧(DAC)和拉曼光谱技术,测量了四苯基卟啉J聚集体在13GPa内的高压拉曼光谱,根据各个拉曼谱带的频移-压强变化曲线得出在13GPa内Tpp J聚集体无相变发生,并且高波数(1010～1600cm-1)和低波数(230～330cm-1)区的斜率要远大于中等波数(380～1000cm-1)区,这表明对应于高波数和低波数区的化学键比中等波数区更具有易压缩性,并对体积的减小起着重要的作用。根据苯环ψ3C-C面内伸缩振动模式强度逐渐增强的现象提出了分子弹簧垫圈模型。此外,这种分子弹簧垫圈的劲度系数可以通过中位取代基团调控。     

二元混合制冷剂CO2/R600的气液相平衡研究

采用PR状态方程及其混合法则对不同配比的二元混合制冷剂CO2/R600的气液相平衡进行了计算,将计算结果与相关文献数据进行了比对。结果表明,该文的计算结果与文献数据吻合较好,推算方法可用于CO2/R600混合制冷剂的基本热物性预测。     

Spontaneously Regenerative Tough Hydrogels

Sponges, Neofibularia nolitangere, can regenerate spontaneously after being broken down into small pieces, and the regenerated structure maintains the original appearance and function. Synthetic materials with such capabilities are highly desired but hardly achieved. Presented here is a sponge‐inspired self‐regenerative powder from a double‐network (DN) tough hydrogel. Hydrogels are regenerated from their powder form, by addition of water, with preservation of the original appearance and mechanical properties. The powder‐hydrogel‐powder cycle can be repeated multiple times with little loss in mechanical properties, analogous to the regeneration of sponges. These DN hydrogels can be conveniently stored and easily shaped upon regeneration. This work may have implications in the development of regenerative materials for coatings and adhesives.     

双靶磁控溅射聚焦共沉积AlN薄膜生长速率研究

采用直流双靶磁控溅射聚焦共沉积技术在Fe衬底上高速率生长A lN薄膜,结果表明,双靶共沉积技术有效地提高了A lN薄膜生长速率,相同工作气压或低N2浓度时双靶磁控溅射沉积速率约为单靶沉积速率的2倍;随着溅射系统内工作气压或N2浓度的升高,薄膜生长速率不断减小;薄膜择优取向与薄膜生长速率相互影响,随着工作气压的升高,(100)晶面的择优生长减缓了薄膜生长速率的降低,随着N2浓度的升高,(002)晶面的择优生长加剧了薄膜生长速率的降低,而相对较低的溅射沉积速率有利于(002)晶面择优取向生长。     

Smart DNA Hydrogel Integrated Nanochannels with High Ion Flux and Adjustable Selective Ionic Transport

Nanochannels based on smart DNA hydrogels as stimulus‐responsive architecture are presented for the first time. In contrast to other responsive molecules existing in the nanochannel in monolayer configurations, the DNA hydrogels are three‐dimensional networks with space negative charges, the ion flux and rectification ratio are significantly enhanced. Upon cyclic treatment with K⁺ ions and crown ether, the DNA hydrogel states could be reversibly switched between less stiff and stiff networks, providing the gating mechanism of the nanochannel. Based on the architecture of DNA hydrogels and pH stimulus, cation or anion transport direction could be precisely controlled and multiple gating features are achieved. Meanwhile, G‐quadruplex DNA in the hydrogels might be replaced by other stimulus‐responsive DNA molecules, peptides, or proteins, and thus this work opens a new route for improving the functionalities of nanochannel by intelligent hydrogels.     

Poly(phthalazine ether sulfone ketone) as novel stationary phase for stir bar sorptive extraction of organochlorine compounds and organophosphorus pesticides

A novel poly(phthalazine ether sulfone ketone) (PPESK) film prepared by immersion precipitation technique was coated on stir bars for sorptive extraction. Scanning electron micrographs showed that the coating has a denser porous surface (about 1 microm in thickness) with a sponge-like sublayer, and the thickness of the coating was 250 microm. The PPESK coated stir bar has high thermostability (290 degrees C) and long lifetime (50 times). The extraction properties of this stir bar were evaluated for the extraction of both polar and semi-polar analytes, including organochlorine compounds and organophosphorus pesticides. The PPESK stir bar was proved to show higher affinity towards polar compounds than that of PDMS coated stir bar and higher sample load compared with corresponding PPESK fiber. It was applied to the determination of organochlorine compounds in seawater samples and organophosphorus pesticides in juices by gas chromatographic analysis. The effect of sample matrix was evaluated at optimized condition of extraction temperature, extraction time and salt concentration. Limits of detection were in the range of 0.05-2.53 ng L(-1) for organochlorine compounds in seawater samples using electron capture detector (ECD), with precisions of less than 11% RSD. Limits of detection for organophosphorus pesticides were in the range of 0.17-2.25 ng L(-1) and 2.47-10.3 ng L(-1) in grape and peach juice, respectively, using thermionic specified detector (TSD), with precisions of less than 12% RSD and 20% RSD, respectively.     

Organic Memristor Based on High Planar Cyanostilbene/Polymer Composite Films

Organic memristors with low power consumption, fast write/erasure speed, and complementary metal-oxide-semiconductor(CMOS) compatibility have attracted tremendous attention to mimic biological synapses to realize neuromorphic computation in recent years. In this paper, organic resistive switching memory(ORSM) based on (Z)-3-(naphthalen-2-yl)-2-(4-nitrophenyl)acrylonitrile(NNA) and polymer poly(N-vinylcarbazole)(PVK) composite film was prepared by spin-coating method. Device performance based on NNA:PVK composite films with different mass fractions of NNA were systematically investigated. The ORSM based on PVK:40%(mass fraction) NNA composite film exhibited non-volatile and bipolar memory properties with a switching ratio(I_on/I_off) of 24.1, endurance of 68 times and retention time of 10⁴ s, a “SET” voltage(V_set) of -0.55 V and a “RESET” voltage(V_reset) of 2.35 V. The resistive switching was ascribed to the filling and vacant process of the charge traps induced by NNA and the inherent traps in PVK bulk. The holes trapping and de-trapping process occurred when the device was applied with a negative or positive bias, which caused the transforming of the conductive way of charges, that is the resistive behaviors in the macroscopic. This study provides a promising platform for the fabrication of ORSM with high performance.     

TiO2包覆石墨颗粒/硅油电流变液的研究

理论计算表明,介质包覆导体颗粒用作电流变液的分散相,可以获得高剪切应力的电流变液.采用溶胶-凝胶技术在尺度为5-10?μm的石墨颗粒表面成功地包覆了TiO2,获得了金红石相TiO2包覆石墨的复合颗粒.配制成复合颗粒/硅油电流变液,其剪切应力与纯TiO2/硅油电流变液相比,可提高一个数量级.当电场强度为1.7kV/mm时,复合颗粒/硅油电流变液的剪切应力可达1.25kPa,电流密度小于10μA/cm2.     

胺铜或镍配离子的TCNQ电荷转移盐的合成和物理性质

合成了七个胺铜或镍配离子的TCNQ电荷转移盐[ML2][TCNQ]n(TCNQ=7, 7, 8, 8-四氰基对苯二醌二甲烷; n=2, 3;M=Cu, Ni; L=tn, pn, dien, dmtade)。通过元素分析、红外光谱、电子光谱、顺磁共振谱、光电子能谱、磁化率和电导率对这些电荷转移盐进行了表征。结果表明, 这些电荷转移盐分子中存在TCNQ^0和TCNQ^-且TCNQ^0与TCNQ^-之间存在相互作用, 部分电荷从[TCNQ]n^2向[ML2]^2^+转移, 导致化合物中的金属表现为混合价态。七个样品的室温电导率在10^-^5～10^-^1^0S.cm^-^1, 属于有机半导体, 其导电性主要归结为一维TCNQ分子柱的形成。     

SO_4~(2-)_TiO_2-SnO_2、SO_4~(2-)_ZrO_2-SnO_2、SO_4~(2-)_SnO_2催化剂的制备与物性测试研究

制备了SO_4~(2-)/TiO_2-SnO_2、SO_4~(2-)/ZrO_2-SnO_2、SO_4~(2-)/SnO_2催化剂,对它们进行了部分物性测试,并测定了它们对酯化反应的催化活性.发现此类催化剂的酸性很强,远远超过SiO_2-Al_2O_3固体酸催化剂,对酯化反应具有良好的活性.红外光谱测定结果证明,SO_4~(2-)以双配位形式结合在催化剂金属离子上,未生成硫酸盐.同一组成的催化剂的活性与催化剂中的SO_4~(2-)％含量,脱附温度有较大的关系.