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Ｉｎｔｅｒｎｅｔ越来越酷，ＷＷＷ的知名度如日中天。在Ｉｎｔｅｒｎｅｔ上发布公司信息、进行电子商务已经从时髦演化成时尚。作为一个ＷｅｂＭａｓｔｅｒ，你可能对ＨＴＭＬ、Ｊａｖｏｓｃｒｉｐｔ、Ｊａｖａ、Ａｃｔｉｖｅｘ了如指掌，但你是否知道什么是Ｗｅｂ　Ｒｏ...     

Electronic structure characterization of La incorporated Hf-based high-k gate dielectrics by NEXAFS

The electronic structures of lanthunum (La) incorporated hafnium (Hf)-based oxides (HfLaO) and their silicate (HfLaSiO) films were investigated by the Near Edge X-ray Absorption Fine Structure (NEXAFS) technique. The oxygen (O) K-edge spectra, which reflected the hybridized Hf 5d state with the O 2p orbital, were found to reveal features of the unoccupied state of the metal oxides, as well as the conduction-band edge. We also found that, while La incorporation into the Hf-based oxides simply changed the features of the conduction-band structure, subsequent thermal annealing of the La-incorporated films led to a conduction-band edge shift due to an interface silicate reaction and/or local bond rearrangement depending on the La concentration and annealing temperature. The impact of La incorporation into the Hf-based high-k materials on the electronic structure is discussed by taking into account the intrinsic nature of these metal oxides.     

Purification,crystallisation and characterisation of carboxypeptidase from wheat bran

A carboxypeptidase was purified and crystallised from wheat bran. Disc gel electrophoresis at pH 4·0 and ultracentrifugal analysis revealed that the enzyme was essentially homogeneous. The sedimentation constant and isoelectric point were determined to be 6·3 S and 6·0, respectively. The molecular weight of the enzyme was estimated to be 118,000 by a gel filtration method. The enzyme liberated carboxyl terminal amino acid residues from a wide range of N-substituted dipeptides and tripeptides which contain l-proline. It had a pH optimum at pH 4·0 for Z-Glu-Tyr (Z-benzyloxycarbonyl). The K_m and k_cat values for Z-Glu-Tyr at pH 4·0 and 30°C were 0·19 mm and 20 s^?1, respectively. The enzyme hydrolysed Z-Gly-Pro-Leu-Gly-Pro and bradykinin sequentially at pH 4·0 from their carboxyl terminal amino acid residues. The enzyme activity was completely inhibited by DFP.     

Characterization and Sintering of Reactive Cerium(IV) Oxide Powders Prepared by the Hydrazine Method

Nanocrystalline cerium(IV) oxide (CeO₂) powders have been prepared by adding hydrazine monohydrate to an aqueous solution of hydrous cerium nitrate (Ce(NO₃)₃·6H₂O), followed by washing and drying. The lattice parameter of the as-prepared powder is a = 0.5415 nm. The powder characteristics and sinterability of reactive CeO₂ have been studied. The surface areas of powders that have been heated at low temperatures are high, and these surface areas do not decrease to 10 m²/g until the temperature is >1200°C. Crystallite size and particle size are strongly dependent on the heating temperature. Optimum sintered densities are obtained by calcining in the temperature range of 700°–800°C. Ceramics with almost-full density can be fabricated at a temperature as low as 1150°C.     

Transitional processes of flow and heat transfer in a circular pipe with short static mixer

The transitional processes of flow and heat transfer in a circular pipe fitted with a short static mixer were studied with Newtonian and pseudoplastic fluids. An experimental formula, which was derived from the same concept as a well-known transition model of boundary layer flow on a flat plate, coincided well with the experimental results of friction and heat transfer. The transitional Reynolds number for heat transfer was larger than that for flow for both fluids. In heat transfer experiments, the transitional Reynolds number for a pseudoplastic fluid was smaller than that for a Newtonian fluid, and heat transfer augmentation in the transitional region was larger in a pseudoplastic fluid than in a Newtonian fluid. © 1997 Scripta Technica, Inc. Heat Trans Jpn Res 25(4): 254–266, 1996     

DeNO<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript> activity of Ag/γ–Al<Subscript>2</Subscript>O<Subscript>3</Subscript> nanocomposites prepared via the solvothermal route

Ag/γ–Al₂O₃ with silver loading of 3 wt.% were prepared by the solvothermal-calcination reaction of AgNO₃ in mixed water-alcohol solutions at 50–250 °C for 0–120 min, followed by calcinations at 550 °C for 2 h using γ-Al₂O₃ (SSA: 120–409 m² g⁻¹), γ-AlOOH (SSA: 270 m² g⁻¹), Al(OH)₃ (SSA 10 m² g⁻¹), Al(OCH(CH₃)₂)₃ and Al(NO₃)₃ as an aluminum source. The resultant product produced by the solvothermal reaction was Ag/γ–AlOOH even though a different aluminum source was used and Ag/γ–AlOOH was converted to Ag/γ–Al₂O₃ by the following calcinations. However, the characteristics of them changed greatly depending on the alumina source. The deNO _x catalytic performance of Ag/γ–Al₂O₃ also greatly changed depending on the aluminum precursor and solvothermal solvent in the order γ-AlOOH = γ-Al₂O₃ >> Al(OCH(CH₃)₂)₃ >> Al(NO₃)₃ > Al(OH)₃ and methanol = ethanol > 1-propanol > butanol >> hexanol, since the amount and size of silver particle impregnated and specific surface area of the product changed markedly. Ag/γ–Al₂O₃ prepared by solvothermal-calcination method consisted of homogeneously dispersed fine particles of silver and showed better performance for NO _x decomposition than that by conventional impregnation-calcination method.     

Nonlinear control system using learning Petri network

According to recent understanding of brain science, it is suggested that there is a distribution of functions in the brain, which means that different neurons are activated depending on which sort of sensory information the brain receives. We have already developed a learning network with a function distribution which is called the Learning Petri Network (LPN) and have shown that this network could learn nonlinear and discontinuous mappings which the Neural Network (NN) cannot. In this paper, a more realistic application which has dynamic characteristics is studied. From simulation results of a nonlinear crane control system using LPN controller, it is clarified that the control performance of LPN controller is superior to that of NN controller. © 2000 Scripta Technica, Electr Eng Jpn, 131(3): 58‐69, 2000     

纳豆菌和乳酸菌的耐酸性比较研究

研究比较纳豆菌和乳酸菌的耐酸性,观察菌株的发酵过程.从不同分离源中分离出9株纳豆菌和35株乳酸菌,对这44株菌进行在人工胃液中耐酸性的测定,结果显示,纳豆菌的耐酸性普遍高于乳酸菌.最后,对耐酸性较强的两种菌的生长曲线分别进行测定和比较,结果表明纳豆菌的生长快于乳酸菌,并能在发酵过程中基本保持发酵液pH的稳定.