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961.
采用热蒸发气相沉积聚合方法(VDP)制备了聚酰亚胺(PI)薄膜,研究了设备、衬底温度、升温过程和单体配比因素对PI薄膜表面形貌的影响。利用干涉显微镜和扫描电镜对薄膜表面形貌进行了分析;利用原子力显微镜测定了薄膜表面粗糙度。结果表明:设定蒸发源-衬底距离为74 cm时可成连续膜;蒸发源采用一段升温和多段升温时,膜表面均方根粗糙度分别为291.23 nm和61.99 nm;采用细筛网可防止原料的喷溅;均苯四甲酸二酐和4,4′-二氨基二苯醚(PMDA和ODA)单体沉积速率比值为0.9∶1时,膜表面均方根粗糙度值可减小至3.30 nm;沉积衬底温度保持30 ℃左右时,膜表面均方根粗糙度为4.01 nm, 随温度的上升,膜表面质量会逐渐变差。 相似文献
962.
963.
Yao S Hinds MG Murphy JM Norton RS 《Journal of magnetic resonance (San Diego, Calif. : 1997)》2011,211(2):243-247
Conformational or chemical exchange can cause significant sensitivity loss in NMR spectroscopy through resonance broadening for nuclear spins involved in these processes. While this effect may sometimes be alleviated by manipulating experimental conditions such as temperature, pH, and buffers, conditions optimal for all resonances are not always achievable. As a consequence, any means of recovering or minimizing this exchange-induced sensitivity loss is potentially of significant value in regaining information otherwise lost. We report the experimental observation of significant sensitivity gain for nuclear spins undergoing chemical exchange with solvent (water) at exchange rates ca 1-10 s(-1) in (1)H-(15)N correlation spectra of proteins acquired with band-selective pulses (the SOFAST-HMQC sequence). 相似文献
964.
F–B–S tri-doped titanium dioxide thin films on common glass were prepared by a modified sol–gel method, in which tetrabutyl
titanate (Ti(OC4H9)4) was chosen as the precursor and boric acid (H3BO3), sodium fluoride (NaF), and thiourea (N2H4CS) were employed as boron, fluorine, and sulfur sources, respectively. The microstructure and optical property were characterized
by X-ray diffraction, high-resolution field emission scanning electron microscopy, N2 adsorption–desorption isotherms, photoluminescence spectrum, and UV–Vis diffraction reflectance spectroscopy. The photocatalytic
performances were evaluated by decomposition of organic dyes in solution. The experimental results revealed that the F–B–S
tri-doped TiO2 thin film was composed of uniform round-like nano-particles with the size range of 5–8 nm. F–B–S tri-doping not only significantly promoted the UV-induced photodecomposition activities of TiO2 films but also extended the optical response of TiO2 red shift to visible light region, herein improving the visible light-induced degradation of organic dyes. The improvement
mechanism by F–B–S tri-doping was also discussed. 相似文献
965.
The structure of the Si3Ox (x=2, 3) cluster is investigated; we find that the geometry of Si3O2 is similar to that of Si3O3 except for the oxygen-deficient defect structure (Si-Si band) which exists only in the Si3O2 cluster. It is known that oxygen-deficient defects are used to explain visible luminescence (especially blue, purple and ultraviolet light) from silicon-based materials, which are directly bound up with the excited states of the molecules. Therefore the excitation properties of the two clusters are also studied. Our results show that the absorption spectrum of Si3O2 is concentrated in the visible light region. In contrast, the absorption spectrum of Si3O3 is mainly located in the ultraviolet light region. The calculations are perfectly consistent with experimental data and also support the theory of oxygen-deficient defects. 相似文献
966.
TOGANO Y AOI N BABA H HONDA T OKADA K HARA Y IEKI K ISHIBASHI Y ITOU Y IWASA N KANNO S KAWABATA T KIMURA H KONDO Y KURITA K KUROKAWA M MORIGUCHI T MURAKAMI H OISHI H OTA S OZAWA A SAKURAI H SHIMOURA S SHIODA R TAKESHITA E TAKEUCHI S YAMADA K YAMADA Y YASUDA Y YONEDA K MOTOBAYASHI T 《中国科学:物理学 力学 天文学(英文版)》2011,(Z1)
Two-proton relative momentum distributions from the break-up channels 23Al→p+p+21Na and 22Mg→p+p+20Ne at an energy of 60-70 A MeV have been measured together with two-proton opening angles at the projectile fragment separator beamline (RIPS) in the RIKEN Ring Cyclotron Facility. The results demonstrate the existence of diproton emission component from single-step 2He for highly excited 23Al and 22Mg. 相似文献
967.
C. B. Li Y. Zheng X. G. Wu X. F. Li C. Y. He G. S. Li S. H. Yao B. B. Yu X. P. Cao S. P. Hu J. L. Wang J. B. Lu Y. J. Ma D. Yang H. D. Wang K. Y. Ma G. Y. Liu L. Li C. Xu Y. Y. Cheng 《The European Physical Journal A - Hadrons and Nuclei》2011,47(11):1-7
High-spin states in 114In were populated using the reaction 110Pd(7Li, 3n)114In at a beam energy of 26MeV. The level scheme of 114In consisting of six bands is established up to excitation energy ~ 5MeV and spin ~ 17 ? with the addition of 58 new transitions and their configurations are discussed. The intense positive-parity dipole cascade may be interpreted as shears band based on $ \pi$ [(g 9/2)-1] ? $ \nu$ [(g 7/2/d 5/2)(h 11/2)2] configuration. The $ \Delta$ I = 2 bands based on proton excitation have been observed in 114In for the first time. 相似文献
968.
Taichang Zhang Delin Zhu Nan Yao Fei Qi Chung K. Law 《Proceedings of the Combustion Institute》2011,33(2):1819-1825
Catalytic ignition and heat release of methane oxidation over a Pd wire covered with a 1–2 μm PdO surface layer were investigated by wire microcalorimetry over the temperature range of 600–770 K and pressure range of 0.5–4 atm. Ignition temperatures and heat release rates for different methane concentrations (1–4 vol.% in dry air) were determined, showing that the ignition temperatures decrease with increasing the methane concentration and increasing ambient pressure. At total pressure of 1 atm and 2% methane concentration, the global activation energy for the catalytic reaction is 21.5 ± 0.9 kcal/mol and 14.3 ± 0.2 kcal/mol in the temperature ranges of 600–670 K and 670–770 K, respectively. The reaction order for methane is 0.9 ± 0.1 over the temperature range of 630–770 K. 相似文献
969.
A low specific on-resistance (R S,on) silicon-on-insulator (SOI) trench MOSFET (metal-oxide-semiconductor-field-effect-transistor) with a reduced cell pitch is proposed.The lateral MOSFET features multiple trenches:two oxide trenches in the drift region and a trench gate extended to the buried oxide (BOX) (SOI MT MOSFET).Firstly,the oxide trenches increase the average electric field strength along the x direction due to lower permittivity of oxide compared with that of Si;secondly,the oxide trenches cause multiple-directional depletion,which improves the electric field distribution and enhances the reduced surface field (RESURF) effect in the SOI layer.Both of them result in a high breakdown voltage (BV).Thirdly,the oxide trenches cause the drift region to be folded in the vertical direction,leading to a shortened cell pitch and a reduced R S,on.Fourthly,the trench gate extended to the BOX further reduces R S,on,owing to the electron accumulation layer.The BV of the MT MOSFET increases from 309 V for a conventional SOI lateral double diffused metal-oxide semiconductor (LDMOS) to 632 V at the same half cell pitch of 21.5 μm,and R S,on decreases from 419 m · cm 2 to 36.6 m · cm 2.The proposed structure can also help to dramatically reduce the cell pitch at the same breakdown voltage. 相似文献
970.
The spin-polarized electronic band structures, density of states (DOS), and magnetic properties of Co-Mn-based Heusler alloys CoMnSb and Co2MnSb have been studied by first-principles method. The calculations were performed by using the full-potential linearized augmented plane wave (FP-LAPW) within the spin-polarized density functional theory and generalized gradient approximation (GGA). Calculated electronic band structures and the density of states are discussed in terms of the contribution of Co 3d74s2, Mn 3d54s2, and Sb 5s25p3 partial density of states and the spin magnetic moments were also calculated. The results reveal that both CoMnSb and Co2MnSb have stable ferromagnetic ground state. They are ideal half-metallic (HM) ferromagnet at their equilibrium lattice constants. The calculated total spin magnetic moments are 3μB for CoMnSb and 6μB for Co2MnSb per unit cell, which agree with the Slater-Pauling rule quite well. 相似文献