大深度地下连续墙钻进精度控制装置的开发

本文介绍了日本最近新开发的大深度地下连续墙钻进精度控制装置的构成、特点、开发经过和实验结果。该装置能够测量钻机的水平位移和扭转,并具有测量精度校正功能。现场施工测量结果与超声波孔壁测定结果基本一致,证实了新开发装置的实用性。     

Mutational analyses of restriction endonuclease--HindIII mutant E86K with higher activity and altered specificity

We have performed mutational analyses of restriction endonucleaseHindIII in order to identify the amino acid residues responsiblefor enzyme activity. Four of the seven HindIII mutants, whichhad His-tag sequences at the N-termini, were expressed in Escherichiacoli, and purified to homogeneity. The His-tag sequence didnot affect enzyme activity, whereas it hindered binding of theDNA probe in gel retardation assays. A mutant E86K in whichLys was substituted for Glu at residue 86 exhibited high endonucleaseactivity. Gel retardation assays showed high affinity of thismutant to the DNA probe. Surprisingly, in the presence of atransition metal, Mo²⁺ or Mn²⁺, the E86K mutant cleaved substrateDNA at a site other than HindIII. Substitution of Glu for Valat residue 106 (V106E), and Asn for Lys at residue 125 (K125N)resulted in a decrease in both endonucleolytic and DNA bindingactivities of the enzyme. Furthermore, substitution of Leu forAsp at residue 108 (D108L) abolished both HindIII endonucleaseand DNA binding activities. CD spectra of the wild type andthe two mutants, E86K and D108L, were similar to each other,suggesting that there was little change in conformation as aresult of the mutations. These results account for the notionthat Asp108 could be directly involved in HindIII catalyticfunction, and that the substitution at residue 86 may bringabout new interactions between DNA and cations.     

水热条件对易烧结PZT粉体合成的影响

用水热法合成了低温烧结用PZT[Pb(Zr0 .5 3 TiO0 .47)O3]粉体。探讨了水热条件对合成粉体性能的影响。合成时添加了有助于烧结的Fe2 + ,Bi3 + ,Cu2 + 等离子化合物 ,经X ray,SEM ,TG DTA及比表面积的测定 ,表明 :当反应介质为 4mol/LNaOH ,时间 2h ,反应温度 2 0 0℃时合成后的粉体有良好的烧结性。粉体中外加了微量BCW[Ba(Cu0 .5 W0 .5 )O3] ,使PZT陶瓷在 850℃温度下即可烧成 ,密度可达理论值 98%。     

Separation of sago starch from model suspensions by tangential flow filtration

Sago starch producing mills in Malaysia generate approximately 20 tons of effluent per ton of starch produced. The effluent contains mainly starch and very low concentrations of nitrogenous compounds. The starch could be recoverable by Tangential Flow Filtration (TFF). The aim of this study was to apply TFF to separate the starch from 1% (w/v) model suspensions in simulated sago effluent. Polysulfone membrane filter cassettes of 0.45 µm pore size and 0.1 m² were used for these experiments. Fifty-liter of a starch suspension was concentrated to less than 10-L. The main finding in this study was that increasing membrane filtration area improved the filtration efficiency from 81% to 85.4%, when lower transmembrane pressure (TMP) was employed. Turbidity, total suspended solids, and chemical oxygen demand before and after the treatment were significantly different (p?<?0.05). In conclusion, TFF functioned efficiently to separate sago starch from suspensions. It was found that membrane area and low TMP enhanced the flux rate and minimized the reversible clogging. Moreover, membrane permeability was recovered and cleaned almost to its original permeability.     

Self-aligned formation of nano-holes to arrayed micro glass tubes

Microreactors and micro-fluidic devices require micro-tube structures to reserve and manipulate extremely small volume of liquid specimen, and nano-hole on the micro-tube is useful for its injection, aspiration and filtration, etc. In the present study, we attempted to develop a precise etching process to form nano-hole to the edge part of the micro glass tube by controlling SiO₂ etching conditions with diluted aqueous HF solution. The arrayed micro-glass-tubes were fabricated by electrochemical etching of Si wafer followed by wet-thermal oxidation. The bottoms of arrayed micro-glass-tubes were exposed from Si wafer, which possessed pyramid-shape edges. The etching with optimized concentration of HF formed uniform nano-holes only at every bottom edge, indicating self-alignment of the etching process. The diameter of the nano-holes was controllable in the range of ca. 100-500 nm by adjusting the immersion duration and thickness of the glass tube. Nonlinear diffusion of fluoride species to the bottom edges could be the origin of the self-aligned formation of nano-holes at the bottom edges.     

Click Peptide concept: o-acyl isopeptide of islet amyloid polypeptide as a nonaggregative precursor molecule

The O-acyl isopeptide (1) of islet amyloid polypeptide (IAPP), which contains an ester moiety at both Ala8-Thr9 and Ser19-Ser20, was prepared by sequential segment condensation based on the O-acyl isopeptide method. Isopeptide 1 possessed nonaggregative properties, retaining its random coil structure under the acidic conditions; this suggests that the insertion of the O-acyl isopeptide structures in IAPP suppressed aggregation of the molecule. As a result of the rapid O-to-N acyl shift of 1 under neutral pH, in situ-formed IAPP adopted a random-coil structure at the start of the experiment, and then underwent conformational change to α-helix/β-sheet mixed structures as well as aggregation. The click peptide strategy with the nonaggregative precursor molecule 1 could be a useful experimental tool to identify the functions of IAPP, by overcoming the handling difficulties that arise from IAPP's intense and uncontrollable self-assembling nature.     

EXTRACTIONOFTERVALENTLANTHANIDESWITH ACIDIC ORGANOPHOSPHORUS COMPOUNDS

The equilibrium.extraction behavior for a series of tervalent lanthanide ions (Ln³⁺) using a chloroform solution containing di(2-ethyl-hexyl) phosphoric acid (HDEHP), diphenylphosphinic acid (HDPP), dibutylphosphorothioic acid (HDBPT), di-n-octylphosphorodithoic acid (HDOPDT), or di(2-ethylhexyl)phosphorodithioic acid (HDEHPDT), either alone or combined with adduct forming agents is studied. The extracted species are Ln(DEHP) ₃(HDEHP) ₃, Ln(DPP)₃ (HDPP)₃, Ln(DBPT)₃, and are Ln(DBPT)₃(HDERP)₃ in the presence of o-phen and its analogs (B). Extraction constants for the lanthanides follow the order HDPP > HDEHP > HDBPT » HDOPDT. HDPP was the most selective of all the extractants examined. HDOPDT and HDEHPDT were found to be ineffective lanthanide extractants.     

硅表面直接生长十八烷基硅烷小分子自组装单层抗蚀剂的亚稳态氦原子光刻技术

选取不同尺寸和形状的物理掩模,以硅表面直接生长的十八烷基硅烷小分子自组装单分子层作为抗蚀剂,硅（100）为衬底,亚稳态氦原子作为曝光源,利用湿法化学刻蚀方法在衬底上制备具有纳米尺寸分辨率的硅结构图形。基于扫描电子显微镜、原子力显微镜的表征结果表明：原子光刻技术可以把具有纳米尺度分辨率的正负图形通过化学湿法刻蚀技术很好地传递到硅片衬底上,特征边缘分辨率达到20nm左右,具有较高的可信度和可重复性。正负图形相互转化的临界曝光原子剂量约为5×1014atomscm-2,曝光时间约为20min。     

Development of Sodium-Sulfur Batteries

This paper briefly describes sodium sulfur (NAS) battery development with emphasis on the program to establish the technology for the use of a β-alumina solid electrolyte. Since the mid-1980s, NGK INSULATORS, LTD. (NGK) and the Tokyo Electric Power Company (TEPCO) have jointly conducted the NAS battery development program in Japan and, in April 2003, NGK launched production on a commercial scale. A critical aspect of NAS battery development has been achieving low resistance to the flow of sodium ions through the β-alumina solid electrolyte while ensuring material properties consistent with high mechanical strength, as well as with the dimensional stability required for automated manufacturing. The resistance to sodium ion flow within β-alumina depends on three factors: grain resistivity, grain boundary resistivity, and crystal orientation. NGK's approach to addressing these factors is explained in this paper.