Materials Literature
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Pyrolysis of a silica gel hybrid with a starburst dendrimer gives porous silica, in which the pore-size is successfully controlled by the size of the organic component used.
A protein activator of Ca(2+)-calmodulin-dependent protein kinase Ia (CaM kinase Ia) was purified to near homogeneity from pig brain. In the final step of purification, sucrose density gradient centrifugation, CaM kinase Ia activating activity correlated with the presence of a approximately 52-kDa protein band detecte…
The amino acid composition of proteins from mesophilic and extremophilic organisms is commonly assumed to reflect the mechanisms of molecular adaptation to extremes of physical conditions. In this context, halophilic behaviour has been attributed to significantly increased numbers of aspartic and glutamic acid residue…
Surfactant mesophase formation during the synthesis of M41S, the mesoporous material, has been studied using 14N nuclear magnetic resonance spectroscopy. Siliceous gels producing M41S materials displaying hexagonal and lamellar powder X-ray diffraction patterns have been observed to contain hexagonal mesophases which…
OBJECTIVE: The purpose of this study in rodents was to determine the pathologic basis for enhancement patterns of hyperplastic and tumours lymph nodes shown by MR lymphography after IV injection of superparamagnetic iron oxide nanoparticles (AMI-227). MATERIALS AND METHODS: Hyperplastic and tumorous lymph nodes were i…
High-resolution transmission electron microscopy of MCM-41 shows for the first time clearly the hexagonal shape of the pores, and allows direct observation of the transition from a lamellar to the hexagonal phase.
Recent measurements of sonoluminescence produced by a single, stable, pulsating gas bubble indicate that the spectrum can be modeled by that for a blackbody at a temperature of nearly 40 000 K [R. Hiller, S. J. Putterman, and B. P. Barber, ‘‘Spectrum of synchronous picosecond sonoluminescence,’’ Phys. Rev. Lett. 69, 1…
A series of nitrophenyl-amidophenyl-substituted porphyrins with n-Cl7H35 tails have been synthesized and fully characterized. Good Langmuir-Blodgett films of these materials can be prepared on water and transferred successfull to glass slides. Mean molecular areas for the series were measured and found to increase fro…
Employing an explicit atom (EA) model of polymethylene, we have carried out molecular dynamics simulations of n-tridecane (C13H28) melts at experimental densities to compute both equilibrium and dynamic properties. The calibrated EA model reproduces quite well the experimental results of pressure, x-ray diffraction pa…
The piezoelectric properties of ferroelectric and antiferroelectric thin layers were investigated by interferometry as a function of frequency and dc electric bias. Materials included: a ferroelectric lead zirconate titanate (PZT) with a Zr/Ti ratio of 53/47; a relaxor ferroelectric La-modified PZT with a Zr/Ti ratio…
The α-phase crystal of 2-(2′,5′-dihydroxyphenyl)-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazolyl-1-oxy-3-oxide (α-HQNN), which consists of one-dimensional arrays formed by intra- and inter-molecular hydrogen bonds, showed a ferromagnetic phase transition at 0.5 K.
All articles of this category Natural clays can be modified into efficient and versatile catalysts for organic reactions. Among the assets of these heterogeneous catalysts are their lamellar swelling structure, their large specific surfaces, availability of both Brønsted- and Lewis-acidic catalytic sites, and their lo…
Polytetrafluoroethylene (PTFE) grafts placed into the arterial circulation of baboons for 8 weeks under high blood flow (HF) conditions develop a thin intima composed of smooth muscle cells (SMCs) and extracellular matrix beneath an endothelial monolayer. When these grafts are returned abruptly to normal flow (NF), th…
The light-emitting properties of rapid thermally oxidized porous Si are studied by both photoluminescence and cathodoluminescence methods. The structure of the material is examined by transmission electron microscopy, while its oxygen content is determined by x-ray microanalysis. These investigations show that crystal…
摘要 对冲击波法合成的纳米纤锌矿氮化硼（ｗＢＮ）进行了同步辐射真空紫外区的反射光谱测量，得到波长范围１００一２４０ｎｍ区间的反射光谱．利用Ｋｒａｍｅｒｓ－Ｋｒｏｎｉｇ关系计算获得了它的光学常数和介电函数谱，并导出了光电导谱．获得了纳米ｗＢＮ的光学禁带宽度实验值，为８．７±０．５ｅＶ．将以上结果和最新的理论计算进行了比较．观察到了经不同退火温度处理的纳米ｗＢＮ样品结构及尺寸变化对反射光谱和光学性质的影响． Abstract The reflectance spectrum of different wBN was measured. The sample were prepared by shock-wave method and…
The Tg's and heat capacity functions have been measured for a series of Na2S + B2S3 glasses for the first time. Unlike the alkali borates, Tg decreases rapidly as Na2S is added to B2S3. This effect, even in the presence of a rapidly increasing fraction of tetrahedrally coordinated borons, has been associated with the…
Abstract This article focuses on the mineral and organic acid cleaning of iron and steel. It begins with a discussion on the application methods, process selection criteria, solution composition, equipment used, and control of process variables in mineral acid cleaning. The article then describes the advantages and di…
The decay of the adsorbed superoxide radical anions in hydrogen in palladium-promoted yttria is accelerated when the content of palladium ions is increased. The decay kinetics are polyexponential and reflect the tunnelling mode of electron transfer (or electron tunnelling) to superoxide ions. Pd+ ions appearing during…
A method for the computation of environmental costs is described, using dynamic and static factors in a cumulative process to determine them for any stage in textile manufacture. The technique is dependent on an estimate of the projected lifetime of the earth, in conjunction with a value for the rate of consumption of…
A synthesis of 12-azaeburnane skeleton is described. The synthetic sequence has been successfully applied to the preparation of 12-aza analogue of the cerebral vasodilator, ethyl apovincaminate (Cavinton R ) and some related derivatives