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排序方式: 共有117条查询结果,搜索用时 93 毫秒
1.
2.
Jianzhao Liu Jacky W. Y. Lam Matthias Häußler Anjun Qin Ben Zhong Tang 《Journal of Inorganic and Organometallic Polymers and Materials》2009,19(2):133-138
A group of hyperbranched poly(silylenearylene)s are synthesized by homopolycyclotrimerizations of A2-type silylenediynes. The polymers can be readily metallized by complexations of their periphery triple bonds with cobalt
octacarbonyls Co2(CO)8. Pyrolysis of these organometallic polymers gives magnetic ceramics in good yields. Analyses by SEM, TEM, XPS, EDX, and XRD
demonstrate that the ceramics comprise ferromagnetic Co and paramagnetic Co2Si nanocrystallites wrapped by carboneous shell. The ceramics show high magnetic susceptibilities (M
s up to ~50 emu/g) and near-zero coercivity (H
c down to ~0.14 kOe), suggesting that they are good soft magnetic materials with low hysteresis loss.
This article was to be included in the March issue of Volume 19, which was dedicated to Professor Takakazu Yamamoto. The journal
editors sincerely apologize for the omission and delay in publication for which the authors and the guest editor bare no responsibility.
M. Zeldin and A. S. Abd-El-Aziz, Editors. 相似文献
3.
Jungyol Jo Hyoshik Choi Junho Yun Haemi Kim Ogweon Seo Byeonggon Lee 《Thin solid films》2009,517(23):6337-1923
We developed a new method to realize enhancement-mode zinc oxide (ZnO) thin-film transistors (TFT) by metalorganic chemical vapor deposition (MOCVD). We used growth interruptions during MOCVD to encourage complete oxidation of deposited ZnO film, where diethylzinc and oxygen were used as sources. With this method, turn-off characteristics were significantly improved, and threshold voltage was shifted to positive voltages. ZnO TFTs grown at 450 °C showed 107 on/off ratio with 18 cm2/V s mobility, and + 5 V threshold voltage. Our data support that the surface layer is also important in determining ZnO TFT characteristics. 相似文献
4.
Epitaxial (100) CdTe and ZnTe layers with high crystalline quality have been grown on Si substrates by atmospheric pressure
organometallic vapor phase epitaxy (OMVPE). A thin Ge interfacial layer grown at low temperature was used as a buffer layer
prior to ZnTe and CdTe growth. The layers were characterized by Nomarski optical microscopy and double crystal x-ray diffraction.
Double crystal rocking curves with full width at half maximum of about 110 and 250 arc-sec have been obtained for a 7 μm thick
ZnTe layer and a 4 μm thick CdTe layer, respectively. The results presented demonstrate a novel method ofin-situ Si cleaning step without a high temperature deoxidation process to grow high quality CdTe and ZnTe on Si in a single OMVPE
reactor. 相似文献
5.
《Materials Research Bulletin》2004,39(1):9-19
Incorporation of the organometallic fragments MLn=CpFe(dppe)I and CpRu(PPh3)2Cl to the random copolymers [{NP(O2C12H8)}0.8{NP(OC6H4CH2CN)2}0.15{NP(OC6H4CH2CN)(OC6H5)}0.05]n (1) [{NP(O2C12H8)}0.55{NP(OC6H4CH2CN)2}0.2{NP(OC6H4CH2CN)(OC6H5)}0.25]n (2) produce the new compounds of the approximate composition: [{NP(O2C12H8)}x{NP(OC6H4CH2CN·MLn)2}y{NP(OC6H4CH2CN·MLn)(OC6H5)}z]n. The iron derivatives in solution undergo deprotonation of the dppe, probably caused by a polymeric matrix, which in turn causes a spontaneous cross-linking affording sparingly, soluble materials. Thermal analysis of the compounds using DSC and DTA techniques indicates that the incorporation of the organometallic fragment in the copolymer produces materials, which leave an amount of residue depending on the metal, as well as on the functionalization degree of the cyanide groups. Incorporation of the organometallic fragments to the polymer does not produce an improved conductivity in comparison to the insulator polymer without the organometallic fragment. 相似文献
6.
Barium titanium trioxide (BaTiO3) thin films were deposited on fused silica or silicon wafer substrate from barium dipivaloylmethanate (II) (Ba(dpm)2) and titanium tetraisopropoxide (IV) (TTIP) used as precursors in an oxygen microwave plasma. The substrates were dielectrically heated and the substrate temperatures were around 900 K during the film deposition. The deposition was performed for 15 min and the deposits were identified as BaTiO3 by means of X-ray diffraction, X-ray photoelectron spectroscopy, infrared spectroscopy, and ellipsometry. Oxygen and barium atoms and TiO and CO molecules were identified in the plasma. These species would produce higher deposition rates at lower substrate temperatures than those did in the usual thermal metalorganic chemical vapor deposition (MOCVD). The dielectric constant of the BaTiO3 thin film that was directly deposited on the silicon wafer substrate was as low as 101 order of magnitude. Because the deposit reacted with the substrate and an interdiffusional layer was formed, the platinum layer was coated on the silicon wafer substrate in order to prevent the formation of an interdiffusional layer. The dielectric constant then increased to 103 order of magnitude. 相似文献
7.
Syusaku Koie Gentaro Tanaka Hiroki Fukumoto Take-aki Koizumi Takakazu Yamamoto 《Reactive and Functional Polymers》2013,73(9):1180-1187
π-Conjugated polymers based on 1-aminopyrrole and 4-amino-1,2,4-triazole were prepared. Pd-catalyzed organometallic polycondensation gave poly(arylene-ethynylene) (PAE)-type π-conjugated polymers consisting of BOC-protected 4-amino-1,2,4-triazole (Taz(BOC)) units (BOC = t-butoxycarbonyl). The number average molecular weights (Mn) were determined to be 5200–19,200 using GPC. An alternating copolymer of Taz(BOC) and bithiophene (Th–Th) units, P(Taz(BOC)-Th-Th)n-Pd, with an Mn of 10,800 was also prepared by Pd-catalyzed organometallic polycondensation. (Taz(BOC)-Th-Th)n-Pd showed a UV–Vis absorption peak at λmax = 425 nm, which is reasonable for a π-conjugated five-membered ring polymer with a coplanar structure. The deprotection of the BOC group of the polymers proceeded at 200 °C; this BOC-deprotection was investigated using a model compound. The optical and electrochemical properties of the π-conjugated polymers are reported. 相似文献
8.
A. Masoero B. Morten G. L. Olcese M. Prudenziati F. Tango F. Vinai 《Thin solid films》1999,350(1-2):214-218
Magnetic susceptibility from 300 to 900 K, room temperature hysteresis cycles and saturation magnetization were investigated in screen printed and fired NiCo-based layers prepared at various peak temperatures. A bulk NiCo metal sheet of comparable composition was also studied. Values of the magnetic polarization J of 0.28 and 0.435 T were obtained (at 200 kA/m) for films prepared at 750 and 950°C, respectively, in contrast with J=0.98 T for the bulk alloy. In addition, the magnetoresistive responses of the layers and the sheet were plotted. These data suggest that strains, pores and lack of composition homogeneity in the films concur in affecting their magnetic properties, and are responsible for their reduced magnetoresistance anisotropy (e.g. ca. 4% for films as compared to ca. 8% for the bulk alloy at H=80 kA/m). 相似文献
9.
H. Ofuchi T. Akane S. Jinno T. Kuno T.Hirata M. Tabuchi Y. Fujiwara Y. Takeda A. Nakamura 《Materials Science in Semiconductor Processing》2003,6(5-6):469-472
We have investigated local structures of ErP grown by organometallic vapor phase epitaxy Er source: tris(ethylcyclopentadienyl)erbium (Er(EtCp)3 by extended X-ray absorption fine structure (EXAFS) measurement. The EXAFS analysis revealed that NaCl-type ErP and Er–O(–C) compounds coexisted in the case of ErP growth by using Er(EtCp)3. The NaCl-type ErP was preferentially formed on InP(1 1 1)A compared with InP(0 0 1) and InP(1 1 1)B. It is considered that formation of unexpected Er–O(–C) compounds is due to low but significant concentration of residual O and/or C in Er(EtCp)3. 相似文献
10.
Ginson P. Joseph M. Vimalan S.M. Ravi Kumar P. Sagayaraj 《Materials Research Bulletin》2007,42(12):2040-2047
Allylthiourea cadmium chloride, a promising non-linear optical material was grown from aqueous solution by slow evaporation technique. Single crystal X-ray diffraction studies reveal that the crystal is trigonal structure with R3C space group. The spectroscopic properties were investigated by recording the Fourier transform infrared and optical absorption spectra. The dielectric studies of the sample were carried out at varying temperatures in the frequency range from 50 Hz to 5 MHz. The thermal properties were studied using thermogravimetric analyses and photopyroelectric technique. It is evident from the thermal studies that the decomposition of the crystal begins around 200 °C. The microhardness test conducted on the grown crystal suggests that the crystal has a relatively high mechanical strength. The second harmonic generation efficiency of the crystal was studied and found to be nearly 1.5 times that of urea. 相似文献