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991.
A nanostructured Al/SiCp composite was fabricated by accumulative roll bonding (ARB) process. The amount of SiC particles introduced into aluminum sheet by one cycle ARB was 0.22 mg/cm2. Increment of the number of ARB cycles increased the amount of SiC particles and enhanced the homogeneity of the distribution of SiC particles. Microstructural change in aluminum matrix with proceeding of the ARB was very similar to that of the ARB-processed unreinforced aluminum; showing a dislocation cell and/or sub-grain structure in samples of lower ARB cycles and ultrafine grained structure in samples of higher ARB cycles. The variation of tensile strength with the ARB was also very similar to that of unreinforced aluminum. However, the effect of strengthening by the ARB was higher in the Al/SiCp composite than in unreinforced aluminum due to an existence of the SiC particles and the formation of finer grains. 相似文献
992.
Miki K Oride K Kimura A Kuramochi Y Matsuoka H Harada H Hiraoka M Ohe K 《Small (Weinheim an der Bergstrasse, Germany)》2011,7(24):3536-3547
In this study, amphiphilic brush-like copolymers conjugated with short alkyl or long polymeric chains of various lengths are synthesized using ring-opening metathesis polymerization (ROMP) of substituted norbornadiene monomers followed by chemical transformations. These amphiphilic copolymers form spherical self-assemblies in aqueous media with diameters of 132-244 nm. The low critical aggregation concentration of these assemblies (2.5 × 10(-3) -1.4 × 10(-5) g/L) indicates that they are quite stable in dilute conditions. An appropriate length of polymer side chain that conjugates the polymer backbone with a hydrophobic ICG (indocyanine green) moiety enhanced the fluorescence intensities of these self-assemblies in aqueous solution as well as in tumor-bearing mice. A longer side chain conjugated with tumor targeting agents could significantly affect the tumor specificity of self-assemblies to a greater extent. The self-assemblies bearing hydrophilic tumor targeting agents, such as a glucosamine molecule and a cyclic RGD (arginine-glycine-asparatic acid) peptide, accumulated in tumor tissues with high selectivity, while those having a hydrophobic targeting agent, such as folate moieties, accumulated in tumor sites with low selectivity. The results demonstrated here unambiguously indicate that the fluorescence intensity and tumor specificity of self-assemblies are strongly affected by the length of side chains that conjugate with dyes and targeting agents. 相似文献
993.
Soshi Sato Kuniyuki Kakushima Parhat Ahmet Kenji Ohmori Kenji Natori Keisaku Yamada Hiroshi Iwai 《Microelectronics Reliability》2011,51(5):879-884
We have experimentally demonstrated structural advantages due to rounded corners of rectangular-like cross-section of silicon nanowire (SiNW) field-effect transistors (FETs) on on-current (ION), inversion charge density normalized by a peripheral length of channel cross-section (Qinv) and effective carrier mobility (μeff). The ION was evaluated at the overdrive voltage (VOV) of 1.0 V, which is the difference between gate voltage (Vg) and the threshold voltage (Vth), and at the drain voltage of 1.0 V. The SiNW nFETs have revealed high ION of 1600 μA/μm of the channel width (wNW) of 19 nm and height (hNW) of 12 nm with the gate length (Lg) of 65 nm. We have separated the amount of on-current per wire at VOV = 1.0 V to a corner component and a flat surface component, and the contribution of the corners was nearly 60% of the total ION of the SiNW nFET with Lg of 65 nm. Higher Qinv at VOV = 1.0 V evaluated by advanced split-CV method was obtained with narrower SiNW FET, and it has been revealed the amount of inversion charge near corners occupied 50% of all the amount of inversion charge of the SiNW FET (wNW = 19 nm and hNW = 12 nm). We also obtained high μeff of the SiNW FETs compared with that of SOI planar nFETs. The μeff at the corners of SiNW FET has been calculated with the separated amount of inversion charge and drain conductance. Higher μeff around corners is obtained than the original μeff of the SiNW nFETs. The higher μeff and the large fractions of ION and Qinv around the corners indicate that the rounded corners of rectangular-like cross-sections play important roles on the enhancement of the electrical performance of the SiNW nFETs. 相似文献
994.
Haigui Yang Masatoshi Iyota Shogo Ikeura Dong Wang Hiroshi Nakashima 《Solid-state electronics》2011,60(1):128-133
A method of Al2O3 deposition and subsequent post-deposition annealing (Al2O3-PDA) was proposed to passivate electrically active defects in Ge-rich SiGe-on-insulator (SGOI) substrates, which were fabricated using Ge condensation by dry oxidation. The effect of Al2O3-PDA on defect passivation was clarified by surface analysis and electrical evaluation. It was found that Al2O3-PDA could not only suppress the surface reaction during Al-PDA in our previous work [Yang H, Wang D, Nakashima H, Hirayama K, Kojima S, Ikeura S. Defect control by Al-deposition and the subsequent post-annealing for SiGe-on-insulator substrates with different Ge fractions. Thin Solid Films 2010; 518: 2342-5.], but could also effectively passivate p-type defects generated during Ge condensation. The concentration in the range of 1016-1018 cm−3 for defect-induced acceptors and holes in Ge-rich SGOI drastically decreased after Al2O3-PDA. As a result of defect passivation, the electrical characteristics of both back-gate p-channel and n-channel metal-oxide-semiconductor field-effect transistors fabricated on Ge-rich SGOI were greatly improved after Al2O3-PDA. 相似文献
995.
We deviate the valence and conduction band energies of stoichiometric CuInS2 crystals based on ab initio electronic band structure calculations using the augmented spherical wave (ASW) method and discuss that at low doping levels, the Madelung energy is a good intrinsic parameter for stabilization of p- or n-type doped CuInS2 crystals. We find that P and Sb atoms are eminently suitable dopants substituted for S atoms for p-type doped CuInS2 crystals with lower resistivity from both the character of electronic states around EF and the Madelung energy. A closer study of the nature of chemical bonds of CuInS2 crystals using first-principles band structure calculation method reveals that In with polyvalence codoping for p-type CuInS2 doped with P results in a decrease of the Madelung energy compared with CuInS2: P, to be an effective method for stabilizing of its ionic charge distributions. 相似文献
996.
Poly(vinyl chloride) (PVC) was ground in air with CaO in the presence of quartz powder as a grinding aid by a small-scale planetary ball mill to investigate the relation of the dechlorination rate of PVC with the impact energy of the balls calculated from a computer simulation based on the Discrete Element Method under various conditions. Mechanochemical dechlorination proceeds as the grinding progresses and is improved with an increase in both the mill speed and the amount of balls introduced into the mill. The same trend can be seen in the relation between the specific normal impact energy of the balls and the rotational speed. The relationship between the observed dechlorination rate and the computed normal impact energy of the balls is linear, with a correlation coefficient of 0.965. This relationship can be used to estimate the dechlorination rate of PVC in a large-scale planetary ball mill. 相似文献
997.
Effect of pressure at primary drying of freeze-drying mouse sperm reproduction ability and preservation potential 总被引:1,自引:0,他引:1
Freeze-dried spermatozoa are capable of participating in normal embryonic development after injection into oocytes and thus useful for the maintenance of genetic materials. We recently reported that long-term preservation of freeze-dried mouse spermatozoa by conventional methods requires temperatures lower than -80 degrees C. Successful permanent preservation of mouse spermatozoa at much higher temperatures requires thorough investigation of the freeze-drying procedure. Thus, we examined the relationship between the pressure at primary drying and the preservation potential of freeze-dried mouse spermatozoa. Three different primary drying pressures were applied to evaluate the effect of pressure on freeze-dried spermatozoa under varying storage conditions and the rate of development measured. The developmental rate of embryos to the blastocyst stage from intracytoplasmic sperm injection by freeze-dried spermatozoa at pressures of 0.04, 0.37, and 1.03 mbar without storage were 59% (337/576), 71% (132/187), and 33% (99/302) respectively. When stored at 4 degrees C for 6 months, the rate was 13% (48/367), 50% (73/145), and 36% (66/182) respectively. These results show that primary drying pressure is an influential factor in the long-term preservation of freeze-dried mouse spermatozoa. 相似文献
998.
Shioda H Satoh K Nagai F Okubo T Seto T Hamano T Kamimura H Kano I 《Shokuhin eiseigaku zasshi. Journal of the Food Hygienic Society of Japan》2003,44(4):203-207
Juice and integument of leaves of 3 Aloe species, Aloe vera, A. ferox and A. africana, are not allowed to be used as food according to the Pharmaceutical Affairs Law in Japan. On the other hand, whole leaves of A. arborescens can be used as food. The present study was designed to distinguish Aloe species by random amplified polymorphic DNA (RAPD) analysis. DNA was isolated from fresh and dried leaves of the 4 Aloe species. Five out of 32 different 10-mer primers examined were useful for analysis. By comparison of the characteristic bands of PCR products on agarose gel, it was possible to distinguish the 4 species. Thus, the botanical species of Aloe in commercial food products can be identified by RAPD analysis. 相似文献
999.
Metabolic engineering--integrating methodologies of molecular breeding and bioprocess systems engineering 总被引:2,自引:0,他引:2
Shimizu H 《Journal of Bioscience and Bioengineering》2002,94(6):563-573
Metabolic engineering is an integrating methodology of analysis and synthesis for the improvement of flux distribution of metabolic pathways in complicated bioprocesses, which are highly multi-hierarchical systems to extend from macroscopic to microscopic levels. Recent progress in metabolic engineering methodologies to improve metabolic pathways in microorganisms was reviewed with many studies in this paper. Metabolic flux distribution was analyzed under different environmental conditions, using a metabolic reaction model. The physiological states of microorganisms were understood by interpreting metabolic flux analysis (MFA). This analysis was also used for development of process operation and control strategy. Cell capability to form a targeted product was analyzed with a metabolic reaction model and linear programming (LP). The use of a 13C-enriched carbon source and nuclear magnetic resonance (NMR) and gas chromatography-mass spectrometry (GCMS) analyses of intracellular and extracellular metabolites enabled determination of a metabolic flux distribution more accurately than the flux distribution determined only by the metabolic reaction model, which involves not only metabolite balances but also energy and redox balances. The comparison of metabolic flux distributions between before and after genetic modification of cells yielded information on the mechanism of regulation of metabolic flux in microorganisms. Finally, integration of bioinformatics and metabolic engineering is discussed, and cyclic modification of the complex bionetwork and process development were emphasized. 相似文献
1000.
Makoto Shiota Toshiaki Uchida Taishi Oda Hiroshi Kawakami 《Journal of food science》2006,71(3):C120-C123
ABSTRACT: We investigated the oxidative stability of soybean oil and fish oil fortified with iron solubilized by lactoferrin (FeLF). Oxidative stability was evaluated by measuring the induction period of the Rancimat test. The induction time of soybean oil added FeCl3 was decreased; however, that of added FeLF was not. This effect of lactoferrin was also observed in the iron-catalyzed oxidation offish oil at temperatures ranging from 50°C to 120°C, and at concentrations of iron ranging from 0 to 500 ppm. Thus, lactoferrin is considered useful as a natural iron stabilizer for food products containing polyunsaturated fatty acids. 相似文献