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排序方式: 共有301条查询结果,搜索用时 15 毫秒
1.
Shiori Hanada 《Tetrahedron letters》2006,47(35):6173-6177
Combination of commercially available platinum catalysts with siloxanes containing more than two Si-H groups is found to be an efficient catalyst system for the reduction of carboxamides to amines. In particular, facile removal of silicon and platinum residues from the product can be achieved by the use of polymethylhydrosiloxanes as reducing reagents. 相似文献
2.
Optical waveguide fabrication and integration with a micro-mirror inside photosensitive glass by femtosecond laser direct writing 总被引:1,自引:0,他引:1
Z. Wang K. Sugioka Y. Hanada K. Midorikawa 《Applied Physics A: Materials Science & Processing》2007,88(4):699-704
Photosensitive glass is a potentially important material for micro-fluidic devices that can be integrated with micro-optical
components for biochemical analysis. Here, we demonstrate the fabrication of optical waveguides inside glass by femtosecond
laser direct writing. The influence of the laser parameters on the waveguide properties is investigated, and it is revealed
that the waveguide mode can be well controlled. The single mode is achieved at a low writing energy, while the multimode is
achieved with increasing energy. In spite of a longitudinally elongated elliptical shape of the cross-sectional profile, the
far-field pattern of the single-mode waveguide shows an almost symmetric profile. The measured propagation loss and the coupling
loss are evaluated to be ∼0.6 dB/cm and ∼1.6 dB at a wavelength of 632.8 nm, respectively, under the conditions of 1.0–2.0 μJ
pulse energy and 200–500 μm/s scan speed. The increased optical loss is associated with a higher waveguide mode at higher
writing energy. Furthermore, the integration of waveguides and a micromirror made of a hollow microplate inside the glass
is demonstrated to bend the laser beam at an angle of 90° in a small chip. The bending loss is estimated to be smaller than
0.3 dB.
PACS 42.62.-b; 42.82.Cr; 82.50.Pt; 42.79.Gn; 42.81.Qb 相似文献
3.
Tetsuji Kametani Hideo Lida Shinzo Kano Sadao Tanaka Keiichiro Fukumoto Shiroshi Shibuya Haruhiko Yagi 《Journal of heterocyclic chemistry》1967,4(1):85-92
Schotten-Baumann reaction of the amine (X) with 4-benzyloxy-3,4′-oxydiphenylacetyl chloride (XI) gave two amides, (XIIa) and (XIIb), which were cyclized to give the corresponding 3,4-dihydroisoquinolines, respectively. Methylation of the above 3,4-dihydro-isoquinolines, followed by hydrolysis, afforded the compounds having the same composition as berbamine (Ia) and oxyacanthine (Ib), whose structures are under examination. 相似文献
4.
Under atmospheric pressure, methanol was produced from CO2–H2 over Pd/ZnO and from CO–H2 over Pd/MgO catalyst. Similar support effects were observed over Cu catalysts. 相似文献
5.
Ono K Yoshida A Saito N Fujishima T Honzawa S Suhara Y Kishimoto S Sugiura T Waku K Takayama H Kittaka A 《The Journal of organic chemistry》2003,68(19):7407-7415
Six novel 2-substituted analogues of 1alpha,25-dihydroxy-19-norvitamin D(3), 6a,b-8a,b, were efficiently synthesized utilizing (-)-quinic acid as the A-ring precursor. The C2-modified A-rings were prepared as 4-alkylated (3R,5R)-3,5-dihydroxycyclohexanones 12-15 from (-)-quinic acid based on radical allylation at the C4 position of methyl (-)-quinicate. The new type of the CD-ring coupling partner 23 was synthesized from 25-hydroxy Grundmann's ketone 19 to apply to the modified Julia olefination to construct a diene unit between the A-ring and the CD-ring. The coupling yields, including a deprotection step, were 47-62%. After the separation of the diastereomers based on C2 stereochemistry, the structure (2alpha or 2beta) was determined by (1)H NMR experiments and compared to DeLuca's 2-methyl- and 2-ethyl-1alpha,25-dihydroxy-19-norvitamin D(3). Thus, the synthesized 2alpha-(3-hydroxypropyl)-1alpha,25-dihydroxy-19-norvitamin D(3) (8a) showed almost the same potency in binding to the bovine thymus vitamin D receptor (VDR) as the natural hormone 1, while its beta-isomer 8b had only a 3% affinity. Both 2alpha-allyl- and 2alpha-propyl-1alpha,25-dihydroxy-19-norvitamin D(3) (6a and 7a) and their 2beta-analogues (6b and 7b) possessed a weak affinity for the VDR. The strong VDR ligand 8a was ca. 36-fold more potent in induction of HL-60 cell differentiation than 1, and interestingly, even the weaker ligand 8b showed a 6.7-fold higher potency in the cell differentiation activity than that of 1. 相似文献
6.
Keiichiro Fukumoto Masatoshi Chihiro Yuichi Shiratori Masataka Ihara Tetsuji Kametani Toshio Honda 《Tetrahedron letters》1982,23(29):2973-2976
Thermolysis of a benzocyclobutene derivative () prepared from norcamphor produced stereoselectively a tetracyclic compound (), which was converted to a lactone () having correct stereochemistry at C7, C8, C9, C11, C13, and C14 positions of (±)-klaineanone. 相似文献
7.
Tadashi Kon Tetsuro Kobayashi Shoichi Kitamura Keiichiro Nakamura Shunji Adachi 《Zeitschrift fur Physik C Particles and Fields》1994,61(2):239-246
In the framework of the minimal supersymmetric standard model (MSSM) and theR-parity breaking model (RBM), we investigate production processes of the scalar top (stop) at HERA energies. These models are characterized by the possible existence of the light stop whose mass is lighter than those of the top quark and the other squarks. It is shown that in the MSSM the stop pair production via boson-gluon fusion gives a sizeable cross section and the most serious background $ep \to ec\bar cX$ could be suppressed by appropriate kinematical cuts. We also show that in the RBM the stop is singly produced in the neutral current processes and we have a clear signal as a sharp peak in the Bjorken parameterx distribution of the scattered electron. 相似文献
8.
Fe/M (M = Ag, Zn and Sn) multilayers prepared by a vacuum evaporation method are studied by Mössbauer spectroscopy (MS), Rutherford backscattering spectroscopy (RBS) and X-ray diffraction (XRD). For the case of an M = Ag multilayer, MS reveals that Fe in the multilayer remains as an-phase down to the layer thickness of 10 nm. This result is in agreement with the RBS result that Fe and Ag form a completely discrete layer structure without any mutual mixing. For the case of M = Zn and Sn, RBS reveals that a considerable mixing has taken place between Fe and Sn during the specimen preparation. MS on Fe/Sn specimens with different layer thickness shows that an alloy phase of about 5 nm thickness is formed at the interface. Structural as well as magnetic properties of the alloy phase are discussed based on MS at different temperatures and on reported results of the intermetallic compound FeSn. 相似文献
9.
Ihara M Katsumata A Setsu F Tokunaga Y Fukumoto K 《The Journal of organic chemistry》1996,61(2):677-684
[Ni(cyclam)](ClO(4))(2)-catalyzed indirect electroreduction of olefinic bromides produced six-membered compounds in low to high yields. The synthetic intermediate 49 of Ipecac and Corynanthe alkaloids was obtained in 88% yield in a highly stereoselective manner. Lactam 66, the synthetic precursor of tacamonine, was prepared in 49% yield as a mixture of two diastereoisomers. The electrolysis of the bromoacetates gave the debrominated compounds in good yields. 相似文献
10.
Tetsuji Kametani Shiroshi Shibuya Hideo Sugi Keiichiro Fukumoto 《Journal of heterocyclic chemistry》1973,10(4):451-453
The absolute configuraiton at the C1-position of 1,2,3,4-tetrahydro-1-phenylisoquinolines can be deduced from the CD curves of either the free base or its methiodide. Furthermore, the absolute con figuration of (+)-2-amino-1-(3-hydroxyphenyl)ethanol (V) was revised and found to have R-configuration at the C1 -position. 相似文献