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排序方式: 共有601条查询结果,搜索用时 125 毫秒
1.
Xin Sun Qiang Lu Moroz V. Takeuchi H. Gebara G. Wetzel J. Shuji Ikeda Changhwan Shin Tsu-Jae King Liu 《Electron Device Letters, IEEE》2008,29(5):491-493
A tri-gate bulk MOSFET design utilizing a low-aspect-ratio channel is proposed to provide an evolutionary pathway for CMOS scaling to the end of the roadmap. 3-D device simulations indicate that this design offers the advantages of a multi-gate FET (reduced variability in performance and improved scalability) together with the advantages of a conventional planar MOSFET (low substrate cost and capability for dynamic threshold-voltage control). 相似文献
2.
为了不使用任何还原剂而获得聚合物固载高分散零价双金属加氢催化剂,利用金属蒸气法制备了3种不同Pd/Cu质量比的聚合物固载双金属原子簇。透射电镜(TEM)和X衍射(XRD)测定表明,Pd-Cu原子簇粒度很小,平均直径小于3.0nm。X射线光电子能谱(XPS)表明,Pd和Cu均为零价态。Pd-Cu原子簇在异丙叉加氢反应中具有很高的活性和选择性。这些结果提供了令人信服的证据,即金属蒸气法可用于在聚合物孔穴内直接而温和地置入小的零价金属原子簇,而且这样制备的聚合物固载金属原子簇很适合于催化应用。 相似文献
3.
A fast modular multiplication method based on precomputation is proposed for use in public-key cryptosystems. The proposed method can compute the Montgomery reduction TR1 mod N only through additions. Furthermore, this is 6.4 times faster than the Montgomery method implemented in modular reduction with a 512 bit modulus when 2.1 MB of memory is used. This memory size is also only 1/4 of that required in the method proposed by Takenaka et al 相似文献
4.
This paper proposes an efficient exact algorithm for the general single-machine scheduling problem where machine idle time
is permitted. The algorithm is an extension of the authors’ previous algorithm for the problem without machine idle time,
which is based on the SSDP (Successive Sublimation Dynamic Programming) method. We first extend our previous algorithm to
the problem with machine idle time and next propose several improvements. Then, the proposed algorithm is applied to four
types of single-machine scheduling problems: the total weighted earliness-tardiness problem with equal (zero) release dates,
that with distinct release dates, the total weighted completion time problem with distinct release dates, and the total weighted
tardiness problem with distinct release dates. Computational experiments demonstrate that our algorithm outperforms existing
exact algorithms and can solve instances of the first three problems with up to 200 jobs and those of the last problem with
up to 80 jobs. 相似文献
5.
Modified quadratic discriminant functions and the application to chinese character recognition 总被引:8,自引:0,他引:8
Kimura F Takashina K Tsuruoka S Miyake Y 《IEEE transactions on pattern analysis and machine intelligence》1987,(1):149-153
Issues in the quadratic discriminant functions (QDF) are discussed and two types of modified quadratic disriminant functions (MQDF1, MQDF2) which are less sensitive to the estimation error of the covariance matrices are proposed. The MQDF1 is a function which employs a kind of a (pseudo) Bayesian estimate of the covariance matrix instead of the maximum likelihood estimate ordinarily used in the QDF. The MQDF2 is a variation of the MQDF1 to save the required computation time and storage. Two discriminant functions were applied to Chinese character recognition to evaluate their effectiveness, and remarkable improvement was observed in their performance. 相似文献
6.
Yasushi Takeuchi Kohjiro Yanagisawa Yuhsuke Tanaka Noriyuki Tsuruoka 《Korean Journal of Chemical Engineering》1997,14(5):377-381
Fixation of nitrogen oxides (NOx) in air onto granular activated carbon impregnated with chemicals was attempted to improve removal efficiency of NOx by activated carbon adsorption. Nitric oxide (NO) and nitrogen dioxide (NO2), were tried to remove by a flow test. Fixed-bed adsorption breakthrough curves were obtained when some kinds of carbon were
used. The amount adsorbed of NO2 changed with the amount and kinds of metallic salts impregnated. Chemicals-impregnated carbons were prepared from a commercial
activated carbon. Among obtained carbons, the one which showed the highest selectivity for NOx was chosen, and its performance with the change in humidity was determined. Removal mechanism of NO2 was estimated, and the carbon impregnated with potassium hydroxide was found to be superior to any other carbon tested. The
amount of the adsorbed NO and that produced by the reduction of NO2 were determined from the breakthrough curves. 相似文献
7.
The flow points of atactic poly(vinyl alcohol) (a-PVA) gels with H2O/dimethyl sulfoxide (DMSO) = 90/10 (v/v) chilled at 20 to ?78°C for 24 h depended on the chilling temperature and were 0–30°C for gels with the initial polymer concentrations (Ci) of 2–5 g/dL, whereas those for H2O/DMSO = 50/50 chilled at 0 to ?78°C were independent of the chilling temperature and were 70–75°C. Syneresis occurred after eight cycles of freezing (?24°C) and thawing (20°C) for a-PVA hydrogels at concentrations above Ci = 4 g/dL and two such cycles for syndiotacticity-rich PVA (s-PVA) hydrogels at concentrations above Ci = 1 g/dL. The extent of syneresis per one cycle for s-PVA hydrogels was higher than that for a-PVA hydrogels at the initial cycles. In the a-PVA hydrogels with an initial polymer concentration of ca. 30 g/dL, syneresis was expected not to occur even after 20 cycles. If all the free water in the gels is assumed to have transuded by syneresis after 20 cycles, the residual water is bound water and is estimated to be six water molecules per one vinyl alcohol monomer unit. © 1994 John Wiley & Sons, Inc. 相似文献
8.
Tetsuya Tanigami Kanna Kai Koji Tanaka Shuji Matsuzawa 《Journal of Inorganic and Organometallic Polymers》2003,13(4):237-253
Poly[bis(-phenoxyethoxy)phosphazene] [PBPEP] had been shown in our previous paper to be a very useful polymer for investigating the crystallization mechanism of polymers, as the crystallization rate of PBPEP is extraordinarily small when isothermally crystallized from the melt. The crystallization of the low molecular weight oligomers of PBPEP was first studied in comparison to the high molecular weight polymers. The oligomer-rich fraction was obtained by fractionation of the as-polymerized sample, which had a broad molecular weight distribution. The fractions thus obtained were characterized by solution viscometry and size exclusion chromatography. The melting temperature and the growth rate of the spherulite from the melt were investigated by differential scanning calorimetry and optical microscopy. The growth rate was one or two orders of magnitude smaller in the oligomer-rich fraction than in the other high molecular weight fractions. A collapsed spherulite appeared in the oligomer-rich fraction at high crystallization temperatures. It is speculated that in the oligomer-rich fraction there is an excess free energy due to defects in the crystal phase. This defect is considerably larger in the oligomer-rich fraction than in the other fractions because a large quantity of short length chains is present. 相似文献
9.
Yuji Tatemoto Masaya Tsunekawa Shuji Yano Takenari Takeshita Katsuji Noda 《Chemical engineering science》2007,62(8):2187-2197
A relatively large wet material was immersed in a fluidized bed of hygroscopic porous particle (silica gel beads) under reduced pressure. And then the drying characteristics were compared with those in the case of inert particle (glass beads). The comparison of drying characteristics is performed experimentally and theoretically. In calculation, the water transfer from the sample to the fluidized bed was considered. The calculation results are in good agreement with the experimental data. The effects of the operational conditions (the pressure in the drying chamber and the temperature of the drying gas) on the drying characteristics were also examined in both fluidizing particles.The drying finishes earlier in the case of hygroscopic porous particle than in the case of inert particle regardless of pressure in the drying chamber, since the water transfer from the sample facilitates the drying in the case of hygroscopic porous particles. The temperature decrement in drying appears in the case of inert particle. This phenomenon is also observed in the case of hygroscopic porous particle, but the decrement degree of the temperature is much smaller than that in the case of inert particle. The difference of the minimum temperature in the sample in drying between the cases of hygroscopic porous particle and inert particle is very slight for different pressures in the drying chamber. 相似文献
10.
Taicho Sato Shuji Ikoma Fusaji Ozawa 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》1980,30(1):225-232
The preparation of gelatinous aluminium hydroxide from aqueous solutions containing a mixture of the chloride, nitrate or sulphate of aluminium and urea by heating at 95°C has been investigated under different conditions. The pH value of aqueous solutions, on heating for a given period of time, gradually increases, rises steeply at pH 4.0–7.5 and finally approaches a constant value. The precipitate appears at about pH 7 in the presence of chloride or nitrate ions and about pH 4 in the presence of sulphate ions. Although the gelatinous precipitates in the chloride and nitrate systems are apparently different from the granular, filterable one in the sulphate system, their compositions are not influenced by the species of aluminium salt. The fresh precipitates exist in an amorphous state, and go to pseudoboehmite by ageing. It seems that the amount of pseudoboehmite increases as the concentration of aluminium salt in aqueous solution decreases. However, the transformation from amorphous aluminium hydroxide to pseudoboehmite is reduced in the presence of sulphate ions. Furthermore, it is found that the X-ray diffraction peak for the (200) plane, as an orthorhombic structure, in the pseudoboehmite precipitated from chloride or nitrate solution is more intense than that from sulphate solution. 相似文献