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排序方式: 共有402条查询结果,搜索用时 15 毫秒
1.
Dr. Koichi Mitsudo Ren Matsuo Toki Yonezawa Haruka Inoue Dr. Hiroki Mandai Prof. Dr. Seiji Suga 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(20):7877-7881
The first electrochemical dehydrogenative C−S bond formation leading to thienoacene derivatives is described. Several thienoacene derivatives were synthesized by dehydrogenative C−H/S−H coupling. The addition of nBu4NBr, which catalytically promoted the reaction as a halogen mediator, was essential. 相似文献
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Fundamental mechanism of femtosecond-laser-induced periodic surface nanostructure formation has been investigated under the condition using superimposed multiple shots at lower fluence than the single-pulse ablation threshold. With increasing the shot number of low-fluence fs-laser pulses, the periodic nanostructure develops through the bonding structure change of target material, the nanoscale ablation with optical near-fields induced around the high curvatures, and the excitation of surface plasmon polaritons (SPPs) to create the nano-periodicity in the surface structure. It is confirmed that non-thermal interaction at the surface plays the crucial role in the nanostructure formation. Based on the mechanism, we have demonstrated that the periodic nanostructure formation process can be controlled to fabricate a homogeneous nanograting on the target surface, using a two-step ablation process in air. The experimental results obtained represent exactly the nature of a single spatial standing SPP wave mode that generates periodically enhanced near-fields for the nanograting formation. The calculated results for a model target reproduce well the nanograting period and explain the characteristic properties observed in the experiment. 相似文献
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Mridul Kanti Mandal Kentaro Yoshimura Lee Chuin Chen Zhan Yu Tadao Nakazawa Ryohei Katoh Hideki Fujii Sen Takeda Hiroshi Nonami Kenzo Hiraoka 《Journal of the American Society for Mass Spectrometry》2012,23(11):2043-2047
We have examined several combinations of solvents with the aim of optimizing the ionization conditions for molecular diagnosis of malignant tumours by PESI-MS. Although the best conditions may depend on the actual species in the sample, the optimal conditions for renal cell carcinoma (RCC) were achieved by using alcohols. PESI-MS successfully delineated the differential expression of phospholipids (PCs) and triacylglycerols (TAGs) in noncancerous and RCC tissues by using these solvent systems. This study paves the way for the application of PESI-MS in medical samples. 相似文献
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Lee Chuin Chen Md. Matiur Rahman Kenzo Hiraoka 《Journal of mass spectrometry : JMS》2012,47(8):1083-1089
Standard field desorption (FD) ionization is implemented under high vacuum condition. In this paper, non‐vacuum FD is performed under a super‐atmospheric pressure environment using untreated tungsten wires as FD emitter, and the ion source was coupled to a commercial linear ion trap mass spectrometer. The operating pressure of the ion source was 6 bars which was high enough to provide sufficient dielectric strength to the working gas so that the high voltage that was required for FD could be applied to the emitter without occurrence of electrical discharge. Non‐volatile sample deposited on the bare tungsten wire FD emitter was heated by flowing direct current through the emitter. Similar to vacuum FD, the formation of conical protrusion of the liquefied sample layer under the strong electric field was also observed. Using the present ion source, high pressure field‐desorption of polar neutral compounds, organic salts and ionic liquids is demonstrated. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
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Useful yield for electrospray droplet impact/secondary ion mass spectrometry was estimated. The mixtures of C60/rhodamine B and C60/Aerosol OT were used as the samples for the positive and negative mode of operations, respectively. By assuming that (i) the desorption efficiencies are about the same for C60, rhodamine B and Aerosol OT, and (ii) desorption of ionic compounds directly gives the secondary ion signals, the useful yields (i.e. total ions generated divided by the total molecules desorbed) for C60 were estimated to be ~0.1. This value should be regarded as the upper limit because the neutralization of positive and negative ions in the plume and desorption of ionic compounds as neutral species are not taken into account. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
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We apply a newly developed many-body theory, tensor optimized antisymmetrized molecular dynamics (TOAMD), to nuclear matter using a relativistic bare nucleon-nucleon interaction in the relativistic framework. It becomes evident that the tensor interaction plays an important role in nuclear many-body system due to the role of the pion in a strongly interacting system. We take the relativistic nuclear matter (RNM) wave function as a basic state and add tensor and short-range correlation operators in the form of pion and omega-meson correlation functions acting on the RNM wave function using the concept of TOAMD. We use the Monte Carlo (Metropolis) method based on the Gaussian integration and the second quantization method for antisymmetrization to calculate all the matrix elements of the many-body Hamiltonian. We write the whole formula of the TOAMD method for numerical calculations of the nuclear binding and saturation properties of nuclear matter using one-boson exchange potential. 相似文献