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161.
162.
An Efficient Selective Oxidation of Alcohols with Potassium Permanganate Adsorbed on Aluminum Silicate under Solvent-free Conditions and Shaking 总被引:2,自引:0,他引:2
Ji-Dong Lou Chun-Ling Gao Li Li Zhi-Gang Fang 《Monatshefte für Chemie / Chemical Monthly》2006,137(8):1071-1074
Summary. A new procedure for the selective oxidation of alcohols to the corresponding aldehydes and ketones with potassium permanganate
supported on aluminum silicate at room temperature under solvent-free conditions and shaking is reported. 相似文献
163.
On application of dc electric fields to a sample of KNO2 (99.9% pure) fused between two heavily nickel plated copper plates the sample does not acquire the potential difference equal
to the applied emf even though there is no external potential drop in the circuit. Also a very large capacitance of the order
of 3000μF is obtained for this sample which is attributed to interfacial polarization effect. An equivalent circuit is given to explain
the dc electrical behaviour of the sample. The idea of solid state battery does not seem to be applicable in the case of fused
KNO2. The large value of the capacitance for dc fields in series with large voltage-dependent resistance is the cause of the slow
discharge of the condenser. 相似文献
164.
微胶囊红磷的制备及在PP中的阻燃应用 总被引:3,自引:0,他引:3
以三聚氰胺甲醛预聚体(MFP)与红磷粉末为原料,过硫酸钾(KPS)为催化剂,采用原位聚合法成功制备出具有高热稳定性的微胶囊红磷(MRP)。通过DSC,SEM,FTIR及XPS等分析手段研究了红磷微胶囊化效果。结果表明,KPS的加入有助于提高MFP的反应活性,使三聚氰胺甲醛树脂有效地包覆在红磷颗粒表面,缩短了反应时间,且此时制备的MRP包覆效果最佳,其氧化反应峰温为480℃,较红磷原料要高出很多,可使用范围变宽。采用熔融挤出法制备了多组不同配方的聚丙烯(PP)复合材料。研究发现,MRP或氢氧化镁(MH)单独使用时阻燃效率低,将它们复配使用后能有效地提高材料的阻燃性能。当PP∶MRP∶MH=100分(phr)∶15(phr)∶50(phr)时,MRP/MH/PP复合材料的极限氧指数为26%,垂直燃烧达到UL-94标准的V-0级。此外,还探讨了可能的阻燃机理。 相似文献
165.
Hany A. Shousha 《辐射效应与固体损伤》2013,168(10):615-627
Studies of the natural γ-emitting radionuclides in different types of cements manufactured by different companies in Egypt (e.g. Iron (HI), Karnak (HK), and Super fine (HSu) products from Helwan Ltd.) have been done to determine their natural levels of radioactivity using a high-purity germanium detector (HPGe). Knowledge of radioactivity present in cement materials enables one to assess any possible radiological risks to human health. The results show that the highest mean values of 226Ra and 232Th activity are 234.01±20.12 and 46.56±4.65 Bq kg?1, respectively, measured in cement sample ‘Iron’ from Helwan company (HI). The corresponding value of 40K is 333.53±26.68 Bq kg?1 measured in cement sample ‘Karnak’ from Helwan company (HK). For 137Cs, this value is 3.27±0.31 Bq kg?1 measured in cement sample (HI). The average concentrations of measured radionuclides in the different cement samples are 72.21±6.39, 24.98±2.24, 134.49±10.45, and 0.58±0.08 Bq kg?1 for 226Ra, 232Th, 40K, and 137Cs, respectively. The measured activity concentrations for these radionuclides were compared with the reported data of other countries. Radium equivalent (Raeq) activities and different hazard indices were calculated to assess the radiation hazard. Iron HI cement sample shows a higher Raeq activity of 311.91±31.10 Bq kg?1. Calculations of absorbed doses in nGy h?1 show that the Iron (HI), Karnak (HK), and Super fine (HSu) products from Helwan company have higher activities than the permissible level (80 nGy h?1). On the basis of the external hazard index (H ex), Raeq activities, and annual effective dose rates for organs (H organ), the natural radioactivity of cement samples is not greater than the recommended values in the established standards and hence safe for use in building constructions and therefore for inhabitants. 相似文献
166.
ABSTRACTPotassium bis(oxalato)zincate(II)dihydrate was prepared and characterized. The sample was irradiated with 60Co gamma rays up to 900?kGy. Infrared, Raman and photoluminescence spectra, X-ray diffraction pattern, surface morphology by AFM and SEM and non-isothermal decomposition of the complex were studied before and after irradiation. Spectral studies suggested significant radiation damage. X-ray diffraction studies showed reduction in unit cell volume and average crystallite size. Both unirradiated and irradiated samples of the complex belong to the hexagonal crystal system. Surface morphology of the complex changed upon irradiation. Thermal decomposition was enhanced. 相似文献
167.
This article tries to personify potassium ferrioxalate crystal as "I" to describe the formation process and the factors affecting the growth of potassium ferrioxalate crystal. After growing into beautiful green crystals, I dreamed I was participating in the jewelry beauty contest. A serious of wonderful conversations between emerald and I revealed the properties and applications of potassium ferrioxalate crystal. It inspires and guides students to understand the growth of crystals and their properties, and it also stimulates students' interest in studying chemistry. 相似文献
168.
Conductivity studies of plasticized anhydrous PEO-KOH alkaline solid polymer electrolyte 总被引:1,自引:0,他引:1
Polyethylene oxide (PEO)–potassium hydroxide (KOH)-based alkaline solid polymer electrolyte films have been prepared by using
methanol as solvent. The highest room temperature ionic conductivity of (2.1 ± 0.5) × 10−8 S cm−1 was achieved for the composition of 70 wt% PEO:30 wt% KOH. The addition of plasticizer, ethylene carbonate, propylene carbonate,
or polyethylene glycol to the highest conductivity of PEO–KOH system helps to increase the ambient ionic conductivity to the
order of 10−6–10−4 S cm−1. The log σ vs 1/T plot of PEO–KOH showed a small conductivity decrease at 50–60 °C range. The small decrease and the hysteresis that occur
during the heating–cooling cycle was overcome by the presence of the plasticizer. X-ray diffraction observation supports the
conductivity results. 相似文献
169.
Cyanide Bridged Platinum-Iron Complexes as Cisplatin Prodrug Systems: Design and Computational Study
Dr. Ariela W. Kaspi-Kaneti Srijana Bhandari Dr. Alexander Schubert Prof. Songping D. Huang Prof. Barry D. Dunietz 《Chemphyschem》2021,22(1):106-111
The potential role of cyanide-bridged platinum-iron complexes as an anti-cancer Pt(IV) prodrug is studied. We present design principles of a dual-function prodrug that can upon reduction dissociate and release concurrently six cisplatin units and a ferricyanide anion per prodrug unit. The prodrug molecule is a unique complex of hepta metal centers consisting of a ferricyanide core with six Pt(IV) centers each bonded to the Fe(III) core through a cyano ligand. The functionality of the prodrug is addressed through density functional theory (DFT) calculations. 相似文献
170.
Preparation of modified MFI (ZSM-5 and silicalite-1) zeolites for potassium extraction from seawater
《Particuology》2018
Modified nanosized MFI (ZSM-5 and silicalite-1) zeolites were successfully synthesized by a hydrothermal method using aluminum isopropoxide and tetraethylorthosilicate as the raw materials. The synthetic zeolites were characterized by X-ray diffraction, energy dispersion spectroscopy, and scanning electron microscopy. The ZSM-5 and silicalite-1 zeolites exhibited ellipse-like and cubic columns, respectively. The K+ ion-exchange equilibrium and ion-exchange capacity of the synthetic zeolites in seawater were investigated. The K+ ion-exchange of synthetic zeolites was rapid and reached an ion-exchange balance in approximately 20 min. The K+ ion-exchange capacity of ZSM-5 and silicalite-1 in seawater was 56.7 and 48.7 mg/g, respectively. The synthetic zeolites have high selectivity toward K+, and therefore, they can be used to selectively extract potassium from seawater. 相似文献