Fabrication of Microporous Films Utilizing Amphiphilic Block Copolymers and Their Use as Templates in Poly(aniline) Preparation

Summary Ordered microporous films were fabricated on the process of solvent evaporation for the solution of amphiphilic poly(acrylic acid)-block-polystyrene under a humid atmosphere. Pore size and its distribution are strongly dependent on the nature of polymers and the evaporation conditions. Poly(aniline) dots were also successfully fabricated via electropolymerization of aniline using a microporous film on indium tin oxide electrode as a template.     

Enzymatic synthesis of fructose 1,6-diphosphate with ATP regeneration in a batch reactor and a semibatch reactor using purified enzymes of Bacillus stearothermophilus

The enzymatic synthesis of fructose 1,6-diphosphate (FDP), an important glycolytic intermediate whose applications in the field of medicine have generated a great deal of interest, was performed in a batch reactor and a semibatch reactor. Using the batch reactor, FDP was first synthesized from glucose by three enzymatic reactions and the ATP consumed was regenerated simultaneously using conjugated enzymes, all of which were purified from crude cell extract of thermophilic Bacillus stearothermophilus. The results of the experiments performed using several enzyme concentrations suggest the existence of an optimum concentration for each enzyme at which the maximum FDP yield can be attained. Since the thermal decomposition of acetyl phosphate reduced the yield of FDP in the batch reactor, the use of a semibatch reactor in which acetyl phosphate was fed continuously was examined. The yield of FDP was improved but the time required to complete the reaction was longer, resulting in a lower productivity of FDP. The yields observed in the two reactors using various enzyme and substrate concentrations were in good agreement with the theoretical predictions calculated based on differential equations derived for the system using the rate equations and the kinetic parameters determined previously. This means that these equations can be used for the analysis of the experimental results as well as for determining the optimum experimental conditions.     

Performance Analysis of Bidding Policy for Competitive Network Providers

This paper proposes an optimum bidding policy in a competitive network provider's environment, where each network provider can bid for individual connection requests according to its own criteria. The proposed bidding policy is based on the concept of shadow price. In other words, each network provider bids only for connection requests with an expected profit exceeding its shadow price. Because such connection request brings profit in the long term, each network provider can maximize its long-term profit by adopting this bidding policy. In this paper, the optimum bidding policy for network providers is analyzed by means of the policy iteration method derived from the Markov decision theory. The economic efficiency of the bidding policy is evaluated using several numerical examples, in which each network provider adopts fixed pricing and state-dependent pricing, respectively. By adopting the bidding policy in both cases, each network provider can maximize its long-term profit while the total users' consumer surplus is slightly reduced.     

Application of Surface Acoustic Wave Sensors for Liquid Helium-4 and Helium-3

A surface acoustic wave (SAW) sensor can be used to determine the acoustic properties of liquid He. We applied this sensor for liquid ³He and liquid ⁴He. Two kinds of SAW were used in this experiment, Rayleigh-SAW and shear horizontal SAW. The damping of Rayleigh-SAW was measured in liquid ⁴He. The results agreed well with the reported values of the acoustic impedance, and the superfluid transition was clearly seen. The damping and the phase shift of shear horizontal SAW were measured in the normal liquid ³He. Temperature dependence of the damping and the phase shift was analyzed by the viscoelastic model, and the results were compared with the transverse acoustic impedance in the normal ³He.     

Early invasive colorectal carcinomas metastatic to the lymph node with attention to their nonpolypoid development

Clinicopathologic study of six cases of early invasive colorectal carcinoma metastatic to lymph node was performed in order to elucidate possible characteristics relating to the risk of metastasis, with particular attention to the growth pattern of the primary tumor. All of the cases had at least one of the well-known risk factors for lymph node metastasis, including moderately or poorly differentiated histologic characteristics, considerable degree of submucosal invasion, and lymphatic invasion. An interesting finding of the present study was the identification of a nonpolypoid growth pattern with no concomitant adenomatous tissue, which seemed to be different from that of "malignant polyps" of previously reported cases showing adenoma-carcinoma sequence. This unique growth feature was found in all of the cases. Therefore, in addition to the accepted risk factors, nonpolypoid growth pattern and absence of adenomatous component may be risk factors predictive of nodal metastasis in patients with early invasive colorectal carcinoma.     

Numerical simulation of fluid flow and heat transfer in a rotating cylindrical container with a counter-rotating disk at the fluid surface

Fluid flow and heat transfer in a rotating cylindrical container with a counterrotating disk at the fluid surface are numerically investigated. The effects of disk rotation and of Prandtl numbers on the fluid flow and heat transfer in the container are discussed. Flow and temperature fields are obtained for various rotational Reynolds numbers of the disk and for Prandtl numbers of the fluid. Nusselt numbers on the walls are calculated for the temperature fields and are compared with available experimental data. © 1999 Scripta Technica, Heat Trans Asian Res, 28(3): 172–182, 1999     

高压下N_2、Ar、CH_4、CO_2和N_2O气体在丝光沸石上的吸附平衡及关联

本文用定容型吸附量测定装置,在压力为3.04×10~3至1.43×10~7Pa范围内,温度为—196、0、25、50和75°C下测定了N_2、Ar、CH_4、CO_2和N_2O等气体在氢型丝光沸石上的吸附平衡数据.实验结果表明:N_2、Ar和CH_4的吸附量随压力增加而增加,直到在6.08×10~6Pa附近达到饱和;CO_2和N_2O的吸附等温线出现了极大值,且不同温度同一吸附质的吸附等温线出现了相互交叉的现象.用扩展了的吸附势理论进行关联,取得了满意的结果.     

A novel method of examining carbonaceous deposits on spent catalyst surfaces

Xenon ion-bombardment used in conjunction with Auger electron spectroscopy was able to discriminate two types of carbonaceous materials accumulated on the surfaces of iron oxide and rhenium/iron-oxide catalysts spent for CO hydrogenation at 250°C and 2.1 MPa. One of the carbonaceous materials was easily eliminated from the surfaces by ion bombardment or by heat-treatment in vacuo at 150°C. On iron oxide only this “soft” carbonaceous material was present. On rhenium/iron oxide, bombardment-resistant “hard” carbonaceous material was also found. The presence of this hard carbonaceous material had little effect on the level of CO hydrogenation activity or the deactivation behavior of this catalytic system.     

Structural analysis of unknown dyes detected in hajikami (ginger pickled in vinegar)

Hajikami (ginger pickled in vinegar) is often used as a relish for grilled fish, and it often contains coloring agents. We detected Rose Bengal (R105) and two unknown dyes in some Hajikami by thin layer chromatography. In this study, we tried to characterize these unknown dyes by HPLC with photodiode array detection (PDA-HPLC), liquid chromatography/mass spectrometry (LC/MS) and nuclear magnetic resonance (NMR). PDA-HPLC analysis showed that the spectra of the unknown dyes resembled that of R105, suggesting the molecular structures of these two dyes are similar to that of R105. Furthermore, LC/MS analysis suggested that the these dyes are R105 in which one or two iodines are replaced by hydrogen. Finally, the two dyes were determined by 1H-NMR and 13C-NMR to be 4,5,6,7-tetrachloro-3',6'-dihydroxy-2',7'-diiodo spiro[isobenzofuran- 1 (3H),9'-[9H]xanthen]-3-one disodium salt and 4,5,6,7-tetrachloro-3',6'-dihydroxy-2',7'-diiodo spiro[isobenzofuran-1(3H),9'[9H]xanthen]-3-one disodium salt.     

Effect of additives on transesterification activity of Rhizopus chinensis lipase

The transesterification activity of powder lipase prepared from the purified lipase of Rhizopus chinensis cells by freeze-drying was quite low compared with that of acetone-dried cells. Additives which could enhance the transesterification activity of the freeze-dried powder lipase were screened. The freeze-dried lipases prepared with certain fatty acid methylesters or certain types of surfactants exhibited high transesterification activity. It was shown that not only the solubility of the freeze-dried lipase in n-hexane but also the organic solvent-stability was enhanced when methyl stearate was added to the lipase solution at the freeze-drying step.