脉冲电化学驱动壳聚糖原位调控制备羟基磷灰石/银复合涂层

采用脉冲电化学驱动壳聚糖原位调控制备了具有抗菌性的羟基磷灰石/银纳米复合涂层.考察了电解液中银离子浓度、钙磷盐浓度等对复合涂层的形貌及成分的影响.探讨了壳聚糖调控羟基磷灰石和银纳米粒子的形成机理,发现在本研究的较佳实验条件为电位-1.3 V,Ag~+浓度为0.06 g·L~(-1),Ca~(2+)浓度为5 mmol·L~(-1).在此基础上对复合涂层的生物活性、生理稳定性能、抗菌性能进行分析.结果表明:复合涂层呈纳米球状,由羟基磷灰石、银、壳聚糖三相组成,并且表面有一层壳聚糖覆盖.银纳米粒子和羟基磷灰石纳米粒子在复合涂层中均匀分布.将复合涂层浸泡在SCPS溶液中37°C浸泡矿化10天后,在复合涂层表面生产细针状排列整齐的羟基磷灰石,且在(002)晶面25.8°处发生显著择优生长,表明复合涂层在快速矿化液中能诱导磷灰石生成,生物活性好.将复合涂层浸泡在37°C PBS溶液中考察其生理稳定性,壳聚糖对复合涂层中Ca~(2+)和Ag~+实现双重离子释放,且降低了离子释放速度,涂层具有良好的生理稳定性.抗菌实验表明复合涂层对大肠杆菌和金黄色葡萄球菌抗菌率达到99%以上,抗菌能力强.     

电泳沉积技术制备海藻酸钙-纳米铜复合抗菌膜

通过调节电解液中纳米铜的含量,经电泳沉积得到海藻酸钙-纳米铜新型抗菌纳米复合膜(Ca~(2+)-Alg-Cu)。以扫描电子显微镜(SEM)、能谱仪(EDS)和傅里叶变换红外光谱(FT-IR)表征了Ca~(2+)-Alg-Cu的结构。使用稀释涂板法研究了Ca~(2+)-Alg-Cu对大肠杆菌(E. coli.)、金黄色葡萄球菌(S. aureus)和绿脓杆菌(P. aeruginosa)的抗菌性能。使用小鼠成纤维细胞(L929)与Ca~(2+)-Alg-Cu共培养表征了其细胞相容性。结果表明,Ca~(2+)-Alg-Cu能够破坏细菌形貌,高效杀死上述3种细菌;Ca~(2+)-Alg-Cu对细胞存活率的影响主要依赖电解液中纳米铜的质量浓度,当纳米铜的质量浓度小于0.4 mg/mL时,细胞存活率大于80%,能够兼顾高效的杀菌活性和良好的生物相容性。     

导电聚吡咯纳米线的电化学无模板法可控合成与表征

以β-萘磺酸(NSA)为掺杂剂,采用电化学无模板法制备了聚吡咯(PPy)纳米线.研究了NSA浓度、吡咯(Py)单体浓度及反应温度对PPy纳米线形貌的影响.分别采用场发射扫描电子显微镜(FE-SEM)和拉曼光谱对PPy纳米线的结构形貌和化学结构进行了表征.结果表明,利用电化学无模板法可得到中空的PPy纳米线;NSA浓度会影响PPy纳米线的取向性;增大Py单体浓度,可制得圆锥状PPy纳米线;低温有利于合成形状细长、紧密堆积的PPy纳米线.PPy纳米线形貌受游离Py浓度及Py-NSA胶束数量影响,通过调节NSA浓度、Py浓度及反应温度改变游离Py浓度及Py-NSA胶束数量,可制得不同形貌的PPy纳米线.     

基于联萘酚衍生物的荧光传感器对Ca~(2+)的选择性测定

设计了基于联萘酚衍生物(LZ)的高选择性的荧光化学传感器,分别采用荧光光谱和紫外-可见光谱法研究了其对Ca~(2+)的识别.结果显示,与其他金属离子,如Ag~+、Al ~(3+)、Bi ~(3+)、Cd~(2+)、Co~(3+)、Cr~(3+)、Cu~(2+)、Fe~(3+)、Hg~(2+)、K~+、Mg~(2+)、Mn~(2+)、Ni ~(2+)、Pb~(2+)、Zn~(2+)相比,探针LZ对Ca~(2+)呈现良好的选择性.并且该探针在486nm处的荧光强度与Ca~(2+)浓度在2~7μmol/L范围内呈现良好的线性关系,其回归系数为0.994,检测限为0.8μmol/L,多次测定的相对标准偏差为2%.     

微波法制备丙三醇碳量子点并用作Fe~(3+)探针

以丙三醇为原料,经一步微波法制备了碳量子点(CDs),所制备的碳量子点粒径分布在4~25 nm之间,其平均粒径为16.5 nm.荧光光谱结果表明,相比于Cu~(2+),Ca~(2+),Mn~(2+),Co~(2+),Fe~(2+),Ni~(2+),Zn~(2+),Na~(2+)Cd~(2+),Mg~(2+),Pb~(2+),K~+和Ag~+等13种常见金属离子,该碳量子点对Fe~(3+)显示出高选择识别性,且Fe~(3+)浓度在10~60μmol/L之间呈现良好的线性关系,检出限为2μmol/L.     

聚吡咯涂层的电化学合成及对神经微电极电性能的影响

通过改变掺杂剂种类、反应时间、电流密度等合成条件, 在神经微电极表面通过电化学沉积一系列厚度及形貌不同的导电高分子聚吡咯(PPy)涂层. 通过X射线光电子能谱及扫描电子显微镜对所得涂层化学组成及形貌进行表征.研究了PPy涂层对神经微电极电性能的影响. 电化学阻抗谱表明, 在神经信号相关的1 kHz频率处, 神经微电极阻抗值可降低至原来的1/55. 循环伏安曲线表明, 随PPy合成时间加长或电流密度提高, 电极总电容量随之增大.     

基于G-四链体-氯化血红素DNA酶比色法测定银离子和汞离子传感器的构筑

利用G-四链体DNA(5′-CTGGGAGGGAGGGAGGGA-3′)与氯化血红素结合形成G-四链体-Hemin DNA酶,其能高效催化H_2O_2氧化反应底物由无色变为绿色,当溶液中有Ag~+或Hg~(2+)存在时会阻碍该DNA酶的形成,导致绿色溶液变浅。基于此,建立了比色法测定Ag~+和Hg~(2+)的传感器。在最佳实验条件下,溶液的吸光度与Ag~+和Hg~(2+)浓度分别在100.0～1 000.0 nmol/L和80.0～800.0 nmol/L范围内具有良好的线性关系,检出限(3δ/Slope)分别为55.9 nmol/L和64.3 nmol/L。该方法具有较好的选择性,采用该方法对实际样品进行测试,结果满意。     

聚吡咯/多壁碳纳米管及其聚氨酯导电复合材料的制备和性能

以羧基化多壁碳纳米管(MWCNTs)做模版剂,采用化学氧化法将吡咯(Py)在羧基化MWCNTs表面聚合制备PPy/MWCNTs导电材料,将其添加到溶剂型聚氨酯(PU)溶液中制备了PPy/MWCNTs/PU导电复合材料,研究了Py用量对PPy/MWCNTs及其PU复合材料性能的影响.研究表明,随Py用量的增加,PPy/MWCNTs的长度不变,管径增大,sp~2和sp~3杂化C含量先提高后减少,N的掺杂梯度降低,PPy/MWCNTs的导电率高于羧基化MWCNTs和PPy.当Py用量为羧基化MWCNTs的20%时,其导电率最大.PPy/MWCNTs中N元素的掺杂程度及其管径变化是引起PPy/MWCNTs/PU复合材料的性能不同的主要原因.增加Py用量,MWCNTs中亲水的羧基因对PPy掺杂而消耗,相同导电材料用量时纳米导电粒子数目相对减少,PPy/MWCNTs/PU复合材料的耐水性能提高,定向应力、储能模量和玻璃化温度降低,导电率先增加后减小.当Py用量为羧基化MWCNTs的15%时,导电率最大.     

电化学沉积含纳米银羟基磷灰石涂层及抗菌性能研究

应用柠檬酸钠还原法制得纳米银胶体溶液,并在钛基表面电泳沉积纳米银颗粒,再由电化学沉积法沉积羟基磷灰石涂层.X射线电子能谱(XPS)、X射线衍射(XRD)和高分辨透射电子显微镜(HRTEM/SEM)证实该涂层含羟基磷灰石(HAp)和Ag,其纳米银颗粒尺度为5~20 nm.抗菌试验表明,涂层中含银量随电泳沉积液纳米银粒子浓度升高而增加,抗菌性也相应增强.但如沉积液中银粒子超过一定浓度时,则其在钛表面会发生明显团聚,导致抗菌性能的降低.据此,初步优化了抗菌效果最佳的复合涂层制备技术.     

基于核壳金@铂纳米粒子的Ag~+比色检测方法

金核铂壳纳米粒子(Au@Pt NPs)具有出色的类过氧化物酶活性,而Ag~+对其催化活性表现出强烈的抑制;基于此,构建了高灵敏的Ag~+比色检测方法。在最佳反应条件下,Au@Pt NPs比色检测Ag~+的线性范围为0.1~10 nmol/L,检出限可达0.05 nmol/L。该方法对汞离子(Hg2~+)也表现出高灵敏的响应,比色检测Hg2~+的线性范围为10~200 nmol/L。将其应用于实际水样中Ag~+的检测,在添加浓度为10,50,100 nmol/L时,回收率为83.8%~97.7%,相对标准偏差为3.0%~9.6%,该方法具有操作简单、灵敏度高、成本低等优点。     

非那雄胺合成工艺改进

非那雄胺能抑制5α-还原酶的活性,明显降低二氢睾酮水平,是一种治疗良性前列腺增生的有效药品。该合成工艺以甾烯酮酸为原料,将其与氯化亚砜反应,无须分离即与叔丁胺反应得17β-酰胺化合物,再氧化开环,环合,氢化,脱氢合成了非那雄胺。经元素分析、IR、1HNMR、13CNMR、MS分析表征了其结构。该法无须使用昂贵的2,2-二吡啶二硫化物和剧毒药品苯亚硒酸酐,且以乙酸铵代替氨气,降低了对设备的要求和腐蚀,更适用于工业生产。     

Dichroism of absorption and polarization of phosphorescence of molecules of the closed form of nitrobenzospirothiopyran

The spectral-polarization characteristics of absorption and phosphorescence of molecules of the initial form of nitro-substituted indolinospirobenzothiopyran were studied in oriented polyethylene films and in solutions with different polarity. An oscillator model of the electron transitions responsible for the formation of absorption and luminescence spectra was suggested. It was established that the principal differences in the spectral and photophysical properties of the compound studied and its oxygen-containing analog are associated with the fact that the electronegativity of the S atom is lower than that of the O atom. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1143–1146, June, 1997.     

Acid hydrolysis of carboxymethylcellulose of low degree of substitution

Cotton cellulose was swollen in a sodium hydroxide solution and carboxymethylated by a two-bath method for different periods of time for each process. The kinetics of acid hydrolysis and the crystallinity of the swollen and carboxymethylated samples were measured. The proportion of broken bonds, rate constants for hydrolysis, and permeability of cellulose to hydrolyzing agents were calculated. The susceptibility of glycosidic linkages to acid hydrolysis was improved by carboxymethylation more than by swelling in alkali. The increased accessibility of carboxymethylcellulose to acid was regarded as a consequence of increased intra-and intercrystalline swelling and of the glycosidic bonds' weakness caused by the electron-attracting carboxymethyl group on the C-6 position.     

恶臭嗅辨实验室建设探讨

针对恶臭测试的环境影响问题,提出了解决的实例方案,并对方案的要点及优缺点进行讨论,此方案在实际操作中具有较好的效果。     

氯氧化镁生成热的研究

用氧化镁氯化镁水溶液制备了8水合氯氧化镁[nMg(OH)2·MgCl2·8H2O], 并测定了其在盐酸中的溶解热, 实验结果表明, 氯氧化镁溶解热与n值呈线性关系, 根据溶解热求出5Mg(OH)2·MgCl2·8H2O和3Mg(OH)2·MgCl2·8H2O的生成热分别为-7727.1和5888.1kJ·mol^1^-。     

Estimation of Kinetic Parameters of Thermal Oxidation of Ilmenite

The aim of the presented work was the investigation of thermal oxidation of ilmenite in static air atmosphere. The investigations were carried out by use of a derivatograph (MOM, Hungary). The changes of crystallographic structure of investigated samples were identified by X-ray diffractometry on Philips PW-1710 diffractometer. In temperature above 500°C appears structure of hematite Fe₂O₃. On the basis of the thermogravimetric measurements, the contracting area and contracting volume models were found as the best fitting experimental data. This revised version was published online in August 2006 with corrections to the Cover Date.     

Mechanism of action of base-catalyzed oxygenation of phenol derivatives

Cyclopropyl derivative of 2,6-di-tert-butylphenol is synthesized as a probe to investigate the mechanism of base-catalyzed autooxidation of phenol derivatives. Our study indicates that one electron reduction of molecular oxygen from phenolate gives phenoxyl radical 3, a key intermediate of autooxidation. The coupling of phenoxyl radical and superoxide radical gives peroxylate anion 4 and produces the final epoxy alcohol adduct 6.     

Synthesis of phenolic components of Grains of Paradise

Two vanilloids, (5E)-8-(4-hydroxy-3-methoxyphenyl)oct-5-en-4-one (1) and 4-[3-hydroxydecyl]-2-methoxyphenol (2), isolated from the dried seeds of Grains of Paradise (Aframomum melegueta), were synthesized; the latter compound was made as the S-enantiomer and the material derived from the seeds was found to be a 1:1.7 mixture of the R and S isomers. The synthetic route used should allow the preparation of analogs having extended alkyl chains and consequently different lipophilicity, and 3, a homolog of 2, was also prepared.     

解决能源问题的新途径——光解水制氢的研究

面对日益枯竭的能源危机,氢能是一种洁净、最有前景的替代能源。目前在各种制氢的方法中光催化分解水制氢的研究最多,光解水过程中催化剂最关键,本文对利用太阳能光解水的途径、提高光催化反应效率以及光催化剂的开发研究进行了综述。     

Determination of heats of detonation and influence of components of composite explosives on heats of detonation of high explosives

The heats of detonation of 20 simple high explosives and explosive mixtures were determined by means of an adiabatic detonation calorimeter designed by the authors. The results indicated that the performance of the instrument was reliable and the experimental data were very accurate. For explosive mixtures, there was a linear accumulative relationship between the heats of detonation of the explosive mixture and its components. Accordingly, the heats of detonation of explosive mixtures could be calculated directly from the heats of detonation of simple explosives and the characteristic heats of other components. The experiments showed that the gold or brass shell of the cylindrical charge could be substituted by a thick-walled porcelain shell, which had the advantage of cheapness.