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排序方式: 共有132条查询结果,搜索用时 15 毫秒
1.
Sano S Takehisa T Ogawa S Yokoyama K Nagao Y 《Chemical & pharmaceutical bulletin》2002,50(9):1300-1302
Tetrasubstituted (Z)-alkenes were readily prepared through the Horner-Wadsworth-Emmons reactions of methyl 2-[bis(2,2,2-trifluoroethyl)phosphono]propionate with aryl alkyl ketones by employing Sn(OSO(2)CF(3))(2) and N-ethylpiperidine. 相似文献
2.
Kusano G Orihara S Tsukamoto D Shibano M Coskun M Guvenc A Erdurak CS 《Chemical & pharmaceutical bulletin》2002,50(2):185-192
Investigation of the constituents of the fruits of Morus alba LINNE (Moraceae) afforded five new nortropane alkaloids (1-5) along with nor-psi-tropine (6) and six new amino acids, morusimic acids A-F (7-12). The structures of the new compounds were determined to be 2alpha,3beta-dihydroxynortropane (1), 2beta,3beta-dihydroxynortropane (2), 2alpha,3beta,6exo-trihydroxynortropane (3), 2alpha,3beta,4alpha-rihydroxynortropane (4), 3beta,6exo-dihydroxynortropane (5), (3R)-3-hydroxy-12-[(1S,4S)-4-[(1S)-1-hydroxyethyl]-pyrrolidin-1-yll-dodecanoic acid-3-O-beta-D-glucopyranoside (7), (3R)-3-hydroxy-12-[(1S,4S)-4-[(1S)-1-hydroxyethyl]-pyrrolidin-1-yll-dodecanoic acid (8), (3R)-3-hydroxy-12-1(1R,4R,5S)-4-hydroxy-5-methyl-piperidin-1-yll-dodecanoic acid-3-O-beta-D-glucopyranoside (9), (3R)-3-hydroxy-12-[(1R,4R,5S)-4-hydroxy-5-methyl-piperidin-1-yll-dodecanoic acid (10), (3R)-3-hydroxy-12-[(1R,4R,5S)-4-hydroxy-5-hydroxymethyl-piperidin-1-yl]-dodecanoic acid-3-O-beta-D-glucopyranoside (11), and (3R)-3-hydroxy-12-[(1R,4S,5S)-4-hydroxy-5-methyl-piperidin-1-yl]-dodecanoic acid (12) on the basis of spectral and chemical data. 相似文献
3.
Shiho Tokonami Keisuke Nishida Yushi Nishimura Shimpei Hidaka Yojiro Yamamoto Hidenobu Nakao Takuya Iida 《Research on Chemical Intermediates》2014,40(6):2337-2346
We investigated the optical response of a huge number of silver nanoparticles (AgNPs) densely assembled on an organic microsphere, i.e., AgNP-fixed bead, under the collective phenomena of localized surface plasmons. For this purpose, various optical properties of such a AgNP-fixed bead were analyzed in aqueous solution by dark-field optical microscopy and laser Raman microscopy. In particular, in comparison with the optical spectrum of single AgNPs, significant spectral broadening and redshift were observed due to plasmonic superradiance with decreasing interparticle distance to the subnanoscale when using small binder molecules in the AgNP-fixed bead. Furthermore, we observed surface-enhanced Raman scattering and clarified the sensitivity of the signal intensity to the size of the binder molecules between the AgNPs, which can be explained based on optical response theory using a discrete integral with spherical cells. These results and discussion provide a guiding principle for broadband plasmonic light absorbers and for highly sensitive detection of small molecules and nanoscale biomaterials based on vast numbers of nanogaps produced by a bottom-up self-assembly process. 相似文献
4.
Tomomi Kanazawa Kohei Ono Masashi Yamazaki Shiho Cho Fumiyoshi Takano 《Applied Surface Science》2008,254(23):7918-7920
We propose a reactive ion etching (RIE) process of an L10-FePt film which is expected as one of the promising materials for the perpendicular magnetic recording media. The etching was carried out using an inductively coupled plasma (ICP) RIE system and an etching gas combination of CH4/O2/NH3 was employed. The L10-FePt films were deposited on (1 0 0)-oriented MgO substrates using a magnetron sputtering system. The etching masks of Ti were patterned on the FePt films lithographically. The etch rates of ∼16 and ∼0 nm/min were obtained for the FePt film and the Ti mask, respectively. The atomic force microscopy (AFM) analyses provided the average roughness (Ra) value of 0.95 nm for the etched FePt surface, that is, a very flat etched surface was obtained. Those results show that the highly selective RIE process of L10-FePt was successfully realized in the present study. 相似文献
5.
Jun Oshitani Shiho Takashina Mikio Yoshida Kuniaki Gotoh 《Colloids and surfaces. A, Physicochemical and engineering aspects》2009,350(1-3):136-140
The objective of this study is to estimate the contribution of Na+ as a counterion in the formation of H-AOT&Na-AOT-based W/O microemulsions using aqueous NaOH solution by pyranine absorbance measurements. A mixture of an aqueous NaOH solution containing pyranine/H-AOT&Na-AOT/isooctane was emulsified by changing the mixing ratio of Na-AOT (XNa-AOT = 0–1) and the mole fraction of NaOH (XNaOH = [NaOH]/the AOT− concentration in the water pool = 0–1). The phase behavior of the emulsified mixture was evaluated from the absorbance of pyranine at the isosbestic point and by visual observations. W/O microelumsions are formed at the mid-range of XNa-AOT, whereas the emulsified mixture separates into two phases at lower XNa-AOT and higher XNa-AOT. The two phase boundaries shift toward lower XNa-AOT as with increasing XNaOH. The phase behavior depends on the degree of screening of electrostatic repulsions between the polar headgroups of AOT− by the Na+ counterion. Interestingly, nano-sized W/O microemulsions are formed without phase separation using a highly concentrated NaOH aqueous solution when the Na-AOT mixing ratio is appropriately adjusted. The phase behavior was plotted as XNaOH versus XNa-AOT, and the correlation equations for the two phase boundaries were obtained by fitting the points. The contribution of the Na+ counterion from NaOH to W/O microemulsion formation was estimated by the correlation equations. The absorbance of pyranine and the size of W/O microemulsions, as measured by DLS, were plotted as a function of XNa+=(x[Na+ from NaOH]+[Na+ from Na-AOT])/[AOT−], in which x is the ratio contributed by NaOH. The absorbance and size correlates well with XNa+, indicating that XNa+ is a meaningful parameter for quantitatively estimating phase behavior and size variation. 相似文献
6.
An optically active, axially chiral NAD model compound(1) with a quinoline ring system was reduced by the chiral NADH model compound (4), affording a mixture of 1,2- and 1,4-dihydroquinolines. The carbonyl orientation governs the molecular arrangement in the transition state of the reaction and determines the regio- and enantioselectivity of the product. 相似文献
7.
T. Yabe C. Phipps K. Aoki M. Yamaguchi R. Nakagawa C. Baasandash Y. Ogata M. Shiho G. Inoue M. Onda K. Horioka I. Kajiwara K. Yoshida 《Applied Physics A: Materials Science & Processing》2003,77(2):243-249
Laser-supported propulsion of a micro-airplane with a water-covered ablator is demonstrated. The repetitive use of an overlay
structure is experimentally demonstrated with a specially designed water supply. Various transparent overlays are investigated
by the CIP-based hydrodynamic code and by experiments using a pendulum and using a semi-conductor load cell. A momentum-coupling
efficiency of ∼104 N s/MJ is achieved by water–exotic-target experiments, in agreement with the simulation code, which predicts a maximum efficiency
of ∼105 N s/MJ. The concept of laser-supported propulsion can also be used for driving a Mach 5 airplane in the stratosphere, a micro-ship
inside the human body, and a robot in a nuclear power reactor accident, during which large numbers of neutrons make electronic
devices useless.
Received: 7 October 2002 / Accepted: 20 January 2003 / Published online: 28 May 2003
RID="*"
ID="*"Corresponding author. Fax: +81-3/5734-2165, E-mail: yabe@mech.titech.ac.jp 相似文献
8.
Hiroshi Shiho Joseph M. DeSimone 《Journal of polymer science. Part A, Polymer chemistry》2000,38(20):3783-3790
Herein we report a successful dispersion polymerization of 2‐hydroxyethyl methacrylate (HEMA) in a carbon dioxide continuous phase with a block copolymer consisting of polystyrene and poly(1,1‐dihydroperfluorooctyl acrylate) as a stabilizer. Poly(2‐hydroxyethyl methacrylate) was effectively emulsified in carbon dioxide with the amphiphilic diblock copolymer surfactant, and the successful stabilization of the polymerization simultaneously gave spherical particles in the submicrometer range with relatively narrow particle size distributions. The initial concentrations of HEMA and the stabilizer and the pressure had substantial effects on the size of the colloidal particles. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 3783–3790, 2000 相似文献
9.
Yusuke Kumatabara Shiho Kaneko Satoshi Nakata Prof. Dr. Seiji Shirakawa Prof. Dr. Keiji Maruoka 《化学:亚洲杂志》2016,11(15):2126-2129
A piperidine‐derived tetraalkylammonium salt with a non‐coordinating counteranion worked as an effective hydrogen‐bonding catalyst in an aza‐Diels–Alder reaction of imines and a Danishefsky diene. The hydrogen‐bonding interaction between the ammonium salt and an imine was observed as part of a 1H NMR titration study. 相似文献
10.
Makoto Obata Shuto Tanaka Hiroshi Mizukoshi Eika Ishihara Masaki Takahashi Shiho Hirohara 《Journal of polymer science. Part A, Polymer chemistry》2017,55(20):3395-3403
RAFT polymerization of styrene (St) in the presence of 5,10,15,20‐tetrakis(pentafluorophenyl)porphyrin (TFPP) was conducted using 4‐cyano‐4‐(thiobenzoyl)thiopentanoic acid as a chain‐transfer agent and azobisisobutyronitrile as an initiator at 60 °C. The resulting polymer exhibited a chlorin‐like UV‐vis spectrum, which indicated that the polymer possessed a reduced TFPP structure. Furthermore, an SEC trace recorded using UV‐vis detector (λ = 410 nm), which selectively detected the TFPP‐incorporated polymer, shifted toward higher molecular mass as the polymerization progressed. This evidence indicated that TFPP acted as a vinylene‐type monomer, such as maleimide, to form a copolymer, namely, poly(St‐co‐TFPP). The mole fraction of TFPP units was estimated to be 0.74 × 10?3, which was close to that in the feed (1 × 10?3). Chain extension of poly(St‐co‐TFPP) with polyethylene glycol monomethyl ether acrylate (PEGA) was performed to afford the amphiphilic block copolymer poly(St‐co‐TFPP)‐b‐poly(PEGA). The degrees of polymerization of St and PEGA were determined to be 64 and 75, respectively. Poly(St‐co‐TFPP)‐b‐poly(PEGA) formed micelles following dialysis. The median diameter of the micelles in solution was determined to be 16 nm by DLS. The photocytotoxicity of the micelle solution was evaluated in a human glioblastoma cell line (U251) and an N‐methyl‐N'‐nitro‐N‐nitrosoguanidine‐induced mutant of a rat murine RGM‐1 gastric carcinoma mucosal cell line (RGK‐1). © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55 , 3395–3403 相似文献