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排序方式: 共有459条查询结果,搜索用时 31 毫秒
31.
32.
Risa Fukuzumi Dr. Satoshi Kaneko Shintaro Fujii Prof. Tomoaki Nishino Dr. Manabu Kiguchi 《Chemphyschem》2020,21(4):274-274
The front cover artwork was provided by the group of Prof. Nishino, Tokyo Institute of Technology. The image depicts the investigation of the structure and electron transport of the Au, Ag, Cu, Ni, Fe, and Pd atomic junctions doped with dichloroethylene. Read the full text of the Article at 10.1002/cphc.201900988 . 相似文献
33.
Yoshiyuki Shirakawa Yusuke Hayashi Kazunori Kadota Hiroshi Mio Hiroto Ohtsuki Atsuko Shimosaka Jusuke Hidaka 《Journal of nanoparticle research》2008,10(4):577-584
In our previous paper, structural changes of selenium powders ground by a planetary ball mill at various rotational speeds
were investigated for the nanostructural modification of particles using mechanical grinding process. The experimental results
indicated that the amorphisation of Se by grinding accompanies lattice strain, and the lattice strain arises from impact energy
which is more than an energy related to intermolecular interaction. In this paper, molecular dynamics simulations of selenium
have been carried out under compressing conditions of various pressure strengths for obtaining information of the lattice
strain at atomic level. Then, dynamical behaviour of atomic configuration has been discussed in this process. The structural
disordering and formation of the structural defects were estimated by deviations of bond length and angle and the number of
created defects before and after compressing from simulated results. The disordering took place during compressing at various
pressure strengths, and the disordered atoms return to their initial positions at lower pressure. Stable disordered state
and defects after the compression can however remain by compression at more than a certain pressure strength mainly associated
with binding energy of selenium. 相似文献
34.
Suppose that {R n } n ⩾ 0 is a sequence of integers satisfying a binary linear recurrence relation with suitable conditions. We prove the transcendency of the numbers
where a is a nonzero algebraic number and b, c, and d are integers with c ⩾ 1 and d ⩾ 2, and that of similarly constructed numbers, using a new theorem on the transcendence of functions. 相似文献
35.
36.
Electrostatic potentials around a single rodlike polyelectrolyte molecule are calculated by solving the nonlinear Poisson–Boltzmann equation numerically in the presence of externally added salt. The polyion is regarded as a cylinder with a finite length whose side surface is uniformly charged and end surfaces uncharged. The calculations show that the distance to which end effects extend is about half the Debye screening length and is almost independent of the surface charge density and concentration of added salt. For a long polyion whose length is much greater than the Debye length, the end effects can be neglected even for a polyelectrolyte with high surface charges, whereas they play an important role for a short polyion with a length of the same order as the Debye length. In addition, a strong charge condensation is found in the direction of the axis of the cylinder for a long polyion. 相似文献
37.
Hozumi N Yamashita R Lee CK Nagao M Kobayashi K Saijo Y Tanaka M Tanaka N Ohtsuki S 《Ultrasonics》2004,42(1-9):717-722
The authors have proposed a new type of ultrasonic microscopy for biological tissue characterization. The system is driven by a nanosecond pulse voltage, the generated acoustic wave being reflected at the front and rear side of the sliced tissue. In this report, a time-frequency analysis was applied to determine the sound speed thorough the tissue. Frequency dependence of sound speed was obtained with a myocardium of a rat sliced into 10 microm. As the reflected waveform had a significant amount of oscillating component, the waveform was once subjected to the deconvolution process. As the result, two reflections were clearly separated in time domain. Then these two reflections were separately analyzed by time-frequency analysis. Each reflection was extracted by using a proper window function. Phase angles of these reflections at the same frequency were compared. A sound speed micrograph at an arbitrary frequency in between 50 and 150 MHz was successfully obtained. A tendency was found that the sound speed slightly increases with frequency. 相似文献
38.
Shirokawa S Kamiyama M Nakamura T Okada M Nakazaki A Hosokawa S Kobayashi S 《Journal of the American Chemical Society》2004,126(42):13604-13605
A highly regio- and diastereoselective TiCl4-mediated vinylogous Mukaiyama aldol reaction using the chiral vinylketene silyl N,O-acetal has been developed. The present vinylogous Mukaiyama aldol reaction provides a unique and effective means of controlling remote asymmetric induction. The methyl group at the alpha-position is important in achieving a high level of stereoselectivity. From a synthetic point of view, this methodology can provide a one-step construction of delta-hydroxy-alpha,gamma-dimethyl-alpha,beta-unsaturated carbonyl unit that is seen in many natural polyketide products. 相似文献
39.
Takeshi Yabuta Kanji Tsuru Satoshi Hayakawa Chikara Ohtsuki Akiyoshi Osaka 《Journal of Sol-Gel Science and Technology》2000,19(1-3):745-748
Bioactive organic-inorganic hybrids were synthesized through sol-gel processing starting from -methacryloxypropyltrimethoxysilane. NMR-spectroscopic studies showed the presence of silanol groups (Si–OH) and Si–O–Si bonds. In vitro tests of the hybrids for bioactivity with a simulated body fluid (Kokubo solution) indicated that only calcium-containing hybrids could form apatite on their surfaces. Thus the presence of calcium ions was no less important to deposit apatite than the formation of silanol groups or Si–O–Si bonds. 相似文献
40.
Experiments are undertaken on the isotope separation by DC discharge through a narrow capillary of gaseous neon, argon and krypton of natural isotopic abundance. It is confirmed that the heavier isotopes become enriched in the region of cathode, and the lighter isotopes in that of anode. The effect on the obtainable separation factor brought by differences in experimental conditions is examined by changing the capillary tube diameter, tube length, discharge current and discharge pressure. The separation factor improves with increasing the tube length and the discharge current, and with decreasing the discharge pressure and the tube diameter. Ion density and electron temperature are measured in the positive column to compare the present experimental results with existing theories. The order of the isotope enrichment factor is well explained by the theory of the ion diffusive friction force onto isotopically different neutral molecules, together with the theory of the ionization degree of the different isotopic species. 相似文献