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Chinese Physics B 2011年第1期20卷 639-642页

作者：方浩龙浩桑立雯齐胜利熊畅于彤军杨志坚张国义 State Key Laboratory of Artificial Microstructure and Mesoscopic Physics School of PhysicsPeking University

We report on the growth and fabrication of nonpolar a-plane light emitting diodes with an in-situ SiNx interlayer grown between the undoped a-plane GaN buffer and Si-doped GaN layer. X-ray diffraction shows that the crystalline quality of the GaN buffer layer is greatly improved with the introduction of the SiNx interlayer. The electrical properties are also improved. For example, electron mobility and sheet resistance are reduced from high resistance to 31.6 cm2/（V· s） and 460 Ω/respectively. Owing to the significant effect of the SiNx interlayer, a-plane LEDs are realized. Electrolurninescence of a nonpolar a-plane light-emitting diode with a wavelength of 488nm is demonstrated. The emission peak remains constant when the injection current increases to over 20 mA.

关键词： metal-organic chemical deposition III-nitrides nonpolar light emitting diodes

Structural and optical investigation of nonpolar a-plane GaN grown by metal-organic chemical vapour deposition on r-plane sapphire by neutron irradiation

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Chinese Physics B 2012年第2期21卷 531-535页

作者： Xu Sheng-Rui Zhang Jin-Feng Gu Wen-Ping Hao Yue Zhang Jin-Cheng Zhou Xiao-Wei Lin Zhi-Yu Mao Wei National Key Laboratory of Fundamental Science for Wide Band-Gap Semiconductor Technology School of MicroelectronicsXidian UniversityXi'an 710071China

nonpolar （1150） a-plane GaN films are grown by metal-organic chemical vapour deposition （MOCVD） on r-plane （1102） sapphire. The samples are irradiated with neutrons under a dose of 1× 1015 cm-2. The surface morphology, the crystal defects and the optical properties of the samples before and after irradiation are analysed using atomic force microscopy （AFM）, high resolution X-ray diffraction （HRXRD） and photoluminescence （PL）. The AFM result shows deteriorated sample surface after the irradiation. Careful fitting of the XRD rocking curve is carried out to obtain the Lorentzian weight fraction. Broadening due to Lorentzian type is more obvious in the as-grown sample compared with that of the irradiated sample, indicating that more point defects appear in the irradiated sample. The variations of line width and intensity of the PL band edge emission peak are consistent with the XRD results. The activation energy decreases from 82.5 meV to 29.9 meV after irradiation by neutron.

关键词： GaN neutron nonpolar photoluminescence

Groove-type channel enhancement-mode Al GaN/GaN MIS HEMT with combined polar and nonpolar AlGaN/GaN heterostructures

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Chinese Physics B 2016年第8期25卷 340-346页

作者：段小玲张进成肖明赵一宁静郝跃 Key Laboratory of Wide Band-Gap Semiconductor Technology School of Microelectronics Xidian University

A novel groove-type channel enhancement-mode AlGaN/GaN MIS high electron mobility transistor（GTCE-HEMT）with a combined polar and nonpolar AlGaN/GaN heterostucture is presented. The device simulation shows a threshold voltage of 1.24 V, peak transconductance of 182 m S/mm, and subthreshold slope of 85 m V/dec, which are obtained by adjusting the device parameters. Interestingly, it is possible to control the threshold voltage accurately without precisely controlling the etching depth in fabrication by adopting this structure. Besides, the breakdown voltage（VB） is significantly increased by 78% in comparison with the value of the conventional MIS-HEMT. Moreover, the fabrication process of the novel device is entirely compatible with that of the conventional depletion-mode（D-mode） polar AlGaN/GaN HEMT. It presents a promising way to realize the switch application and the E/D-mode logic circuits.

关键词： AlGaN/GaN HEMT enhancement-mode operation groove-type channel nonpolar

Luminescence of a GaN grain with a nonpolar and semipolar plane in relation to microstructural characterization

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Chinese Physics B 2012年第6期21卷 520-524页

作者：周小伟许晟瑞张进成党纪源吕玲郝跃郭立新 Key Laboratory of Wide Band-Gap Semiconductor Technology School of MicroelectronicsXidian University School of Science Xidian University Flight Automatic Control Research Institute AVIC

We report on the growth of the high-quality GaN grain on a r-plane sapphire substrate by using a self-organized SiN interlayer as a selective growth mask. Transmission electron microscopy, scanning electron microscopy, and Raman spectroscopy are used to reveal the effect of SiN on the overgrown a-plane GaN growth. The SiN layer effectively terminates the propagation of the threading dislocation and basal plane stacking faults during a-plane GaN regrowth through the interlayer, resulting in the window region shrinking from a rectangle to a ＂black hole＂. Furthermore, strong yellow luminescence （YL） in the nonpolar plane and very weak YL in the semipolar plane on the GaN grain is revealed by cathodoluminescence, suggesting that C-involved defects are responsible for the YL.

关键词： nonpolar semipolar GaN yellow luminescence

Analysis of nonpolar Components from Ginseng of Different Ages

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American Journal of Plant Sciences 2013年第1期4卷 92-97页

作者： Yizhen Zhang Xunan Lyu Tao Liu Jianping Luo Wenju Zhang Qing Mu School of Biology and Food Engineering Hefei University of Technology Hefei China School of Biology Science Fudan University Shanghai China School of Pharmacy Fudan University Shanghai China

nonpolar components from ginseng of different ages were extracted and analysed using a GC-MS technique to determine their chemical compositions. In total, 23 ingredients, mostly aliphatic compounds, were identified. The compounds extracted included 10,12-octadecadiynoic acid (12.81% - 36.43%), falcarinol (4.95% - 36.79%), n-hexadecanoic acid (0.60% - 9.70%), 9,12-octadecadienoic acid, ethyl ester (0.33% - 5.63%), 5,7-dodecadiyn-1,12-diol (0.97% - 3.85%), (Z)-9-octadecenamide (2.66% - 5.38%) and (Z,Z)-9,12-octadecadienoic acid (0.46% - 5.27%). The two major diyne compositions, falcarinol (8) and 10,12-octadecadiynoic acid (12), were the predominant components (over 50%) of the nonpolar extract of older ginseng. Moreover, the 10,12-octadecadiynoic acid obviously accumulated as the ginseng grew. Sitosterol, a universal metabolite in higher plants, makes up 55.80% of the content of 6-year-old ginseng, but markedly decreases in older ginseng. There was not much difference between the extracts of 8, 10, 12 and 16-year ginsengs, but the extracts of 6-year-old ginseng were distinctive.

关键词： Ginseng Old-Age Ginseng nonpolar Composition GC-MS Falcarinol 10 12-Octadecadiynoic Acid

Particular electrical quality of a-plane GaN films grown on r-plane sapphire by metal-organic chemical vapor deposition

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Journal of Semiconductors 2009年第11期30卷 14-16页

作者：许晟瑞周小伟郝跃毛维张进城张忠芬白琳张金凤李志明 Key Laboratory of Fundamental Sciencefor National on Wide Band-Gap Semiconductor Technology School of MicroelectronicsXidian University Xi'an Division of China Academy of Space Technology

nonpolar （1120） a-plane GaN films have been grown by low-pressure metal-organic vapor deposition on r-plane （1102） sapphire substrate. The structural and electrical properties of the a-plane GaN films are investigated by high-resolution X-ray diffraction （HRXRD）, atomic force microscopy （AFM） and van der Pauw Hall measurement. It is found that the Hall voltage shows more anisotropy than that of the c-plane samples; furthermore, the mobility changes with the degree of the van der Pauw square diagonal to the c direction, which shows significant electrical anisotropy. Further research indicates that electron mobility is strongly influenced by edge dislocations.

关键词： GaN anisotropic HRXRD nonpolar

One-Parameter Equation of State for Gases and Gas Mixtures

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Chinese Journal of Chemical Engineering 2000年第2期8卷 163-166页

作者：李鸿仪 Shanghai Univ Shanghai 200041 Peoples R China

The simplest equation of state that can be applied to calculate the thermodynamic properties of gases is the virial equation with the second coefficient B. The probability of applying the one-coefficient equation Z = exp(A/V) for the calculation of compressibility factor at critical temperature of gases and gas mixtures is investigated. It was verified that the one-coefficient equation of state can be applied to calculated the thermodynamic properties for both normal and strongly polar gases and gas mixtures.

关键词： equation of state virial equation gases fugacity correlation mixture polar nonpolar

Effect of Nitrogen and Phosphorus Starvations on <i>Chlorella vulgaris</i>Lipids Productivity and Quality under Different Trophic Regimens for Biodiesel Production

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American Journal of Plant Sciences 2013年第12期4卷 44-51页

作者： Gianluca Belotti Marco Bravi Benedetta de Caprariis Paolo de Filippis Marco Scarsella Department of Chemical Engineering Sapienza University of Rome Via Eudossiana Rome Italy

In this work the effects of nutrients starvations on Chlorella vulgaris were investigated in different trophic regimens. For all the tested conditions, the cellular response to nutrient starvation and trophic regimen was evaluated on specific growth rate, biomass and lipids productivity, lipids content and quality. These parameters are all crucial for microalgae biodiesel production, but in literature the lipids quality, in terms of polar and nonpolar lipids, is often neglected. Thus the typical high content of polar lipids, a class of molecules that negatively affects the biodiesel production process, of microalgae crude oil is generally not analyzed. In the tested conditions the triggering effect of nitrogen starvation on total lipids productivity is confirmed only in autotrophic regimen, while in mixotrophic and heterotrophic conditions the total lipids productivity is reduced, as a consequence of the lowered biomass productivity, but with an evident compositional shift towards nonpolar lipids production (from 0.5 mg/Ld to 41.6 mg/Ld in mixotrophic regimen). Nitrogen and phosphorus co-starvation induced the highest nonpolar lipids productivity in all trophic regimens. Maximum nonpolar lipids productivity was obtained in nitrogen limited and phosphorus deprived condition during mixotrophic growth, equal to 118.2 mg/Ld, representing the 80% of produced lipids. On the basis of the obtained results, the possibility of a short pre-harvesting cultural step to maximize the nonpolar lipids yield of the crop could be envisaged.

关键词： Biodiesel Chlorella Vulgaris Trophic Regimens Nutrients Starvation nonpolar Lipids Productivity

GaN-based light-emitting diodes on various substrates

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GaN-based light-emitting diodes on various substrates