31 results on '"Yi Zhao"'
Search Results
2. Inverted V-shaped evolution of superconducting temperature in SrBC under pressure*
- Author
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Ru-Yi Zhao, Xun-Wang Yan, and Miao Gao
- Subjects
Superconductivity ,Condensed Matter::Materials Science ,Materials science ,Condensed matter physics ,Condensed Matter::Superconductivity ,General Physics and Astronomy - Abstract
Based on density functional first-principles calculations and anisotropic Eliashberg equations, we have investigated the electronic structure, lattice dynamics, and phonon-mediated superconductivity in newly synthesized layered compound SrBC under pressure. Different from LiBC and MgB2, our calculations surprisingly reveal that SrBC is isotropic in compressibility, due to the accumulation of substantial electrons in the interstitial region. We find that the Sr phonons strongly couple with B-2p z orbital and the interstitial states, giving rise to a two-gap superconductivity in SrBC, whose transition temperature shows an inverted V-shaped dependence on pressure. The maximal transition temperature is about 22 K at 50 GPa. On both sides of 50 GPa, the transition temperature exhibits quasi-linear variation with positive and negative slopes, respectively. Such a variation of transition temperature is infrequent among phonon-mediated superconductors. The competition between enhanced electron–phonon matrix element and hardened phonons plays an essential role in governing the behavior of the critical temperature.
- Published
- 2021
3. Generation of diffraction-free vectorial elliptic hollow beams with space-varying inhomogeneous polarizations*
- Author
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Peng-Yi Zhao, Jian-Ping Yin, and Hui-Rong Li
- Subjects
Physics ,Diffraction ,Optics ,business.industry ,Computer Science::Information Retrieval ,Physics::Optics ,General Physics and Astronomy ,business ,Space (mathematics) - Abstract
Diffraction-free vectorial elliptic hollow beams (vEHBs) are generated by an optical system composed of a short elliptic hollow fiber (EHF) and an axicon. Each beam has a closed elliptic annular intensity profile and space-varying polarization states in its diffraction-free distance of more than 1 m. The generated beams have a counter-clockwise or clockwise periodically-rotated inhomogeneous polarization. And the spin angular momentum (SAM) of the vEHBs is 1ℏ or –1ℏ which is consistent with the type of dual-mode in the EHF and the periodic polarization rotations of the vEHBs. The vEHBs have potential applications in optically trapping and micromanipulating the micro- or nano-particles, quantum information transmission, and Bose–Einstein condensates, etc.
- Published
- 2021
4. Oscillation of S5 helix under different temperatures in determination of the open probability of TRPV1 channel*
- Author
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Li, Tie, primary, Li, Jun-Wei, additional, Pang, Chun-Li, additional, An, Hailong, additional, Geng, Yi-Zhao, additional, and Wang, Jing-Qin, additional
- Published
- 2020
- Full Text
- View/download PDF
5. Oscillation of S5 helix under different temperatures in determination of the open probability of TRPV1 channel*
- Author
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Chunli Pang, Yi-Zhao Geng, Tie Li, Jing-Qin Wang, Hailong An, and Junwei Li
- Subjects
Physics ,Molecular dynamics ,nervous system ,Hydrogen bond ,Oscillation ,musculoskeletal, neural, and ocular physiology ,Helix ,General Physics and Astronomy ,lipids (amino acids, peptides, and proteins) ,Gating ,Molecular physics ,Communication channel ,Open probability - Abstract
Transient receptor potential vanilloid subtype 1 (TRPV1) is a polymodel sensory receptor and can be activated by moderate temperature (≥ 43 °C). Though extensive researches on the heat-activation mechanism revealed some key elements that participate in the heat-sensation pathway, the detailed thermal-gating mechanism of TRPV1 is still unclear. We investigate the heat-activation process of TRPV1 channel using the molecular dynamics simulation method at different temperatures. It is found that the favored state of the supposed upper gate of TRPV1 cannot form constriction to ion permeation. Oscillation of S5 helix originated from thermal fluctuation and forming/breaking of two key hydrogen bonds can transmit to S6 helix through the hydrophobic contact between S5 and S6 helix. We propose that this is the pathway from heat sensor of TRPV1 to the opening of the lower gate. The heat-activation mechanism of TRPV1 presented in this work can help further functional study of TRPV1 channel.
- Published
- 2020
6. Thermal conductivity characterization of ultra-thin silicon film using the ultra-fast transient hot strip method*
- Author
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Yi Zhao, Ran Cheng, Ming Tian, Dong Ni, Jiwu Lu, and Yan-Yan Zhang
- Subjects
Materials science ,Silicon ,business.industry ,General Physics and Astronomy ,chemistry.chemical_element ,Semiconductor device ,Thermal diffusivity ,Thermal conductivity ,chemistry ,Heat transfer ,MOSFET ,Optoelectronics ,Field-effect transistor ,Transient (oscillation) ,business - Abstract
Thermal conductivity is an important material parameter of silicon when studying the performance and reliability of devices or for guiding circuit design when considering heat dissipation, especially when the self-heating effect becomes prominent in ultra-scaled MOSFETs. The cross-plane thermal conductivity of a thin silicon film is lacking due to the difficulty in sensing high thermal conductivity in the vertical direction. In this paper, a feasible method that utilizes an ultra-fast electrical pulse within 20 μ s combined with the hot strip technique is adopted. To the best of our knowledge, this is the first work that shows how to extract the cross-plane thermal conductivity of sub-50 nm (30 nm, 17 nm, and 10 nm) silicon films on buried oxide. The ratio of the extracted cross-plane thermal conductivity of the silicon films over the bulk value is only about 6.9%, 4.3%, and 3.8% at 300 K, respectively. As the thickness of the films is smaller than the phonon mean free path, the classical heat transport theory fails to predict the heat dissipation in nanoscale transistors. Thus, in this study, a ballistic model, derived from the heat transport equation based on extended-irreversible-hydrodynamics (EIT), is used for further investigation, and the simulation results exhibit good consistence with the experimental data. The extracted effective thermal data could provide a good reference for precise device simulations and thermoelectric applications.
- Published
- 2019
7. Protection-against-water-attack determined difference between strengths of backbone hydrogen bonds in kinesin’s neck zipper region
- Author
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Qin, Jing-Yu, primary, Geng, Yi-Zhao, additional, Lü, Gang, additional, Ji, Qing, additional, and Fang, Hai-Ping, additional
- Published
- 2018
- Full Text
- View/download PDF
8. Protection-against-water-attack determined difference between strengths of backbone hydrogen bonds in kinesin’s neck zipper region
- Author
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Qing Ji, Yi-Zhao Geng, Jing-Yu Qin, Gang Lü, and Hai-Ping Fang
- Subjects
0301 basic medicine ,010304 chemical physics ,Hydrogen bond ,Chemistry ,General Physics and Astronomy ,01 natural sciences ,03 medical and health sciences ,Residue (chemistry) ,Molecular dynamics ,Crystallography ,030104 developmental biology ,0103 physical sciences ,Water environment ,Peptide bond ,Kinesin ,Molecule ,Linker - Abstract
Docking of the kinesin's neck linker (NL) to the motor domain is the key force-generation process of the kinesin. In this process, NL's beta 10 portion forms four backbone hydrogen bonds (HBs) with the motor domain. These backbone hydrogen bonds show big differences in their effective strength. The origins of these strength differences are still unclear. Using molecular dynamics method, we investigate the stability of the backbone HBs in explicit water environment. We find that the strength differences of these backbone HBs mainly arise from their relationships with water molecules which are controlled by arranging the surrounding residue sidechains. The arrangement of the residues in the C-terminal part of beta 10 results in the existence of the water-attack channels around the backbone HBs in this region. Along these channels the water molecules can directly attack the backbone HBs and make these HBs relatively weak. In contrast, the backbone HB at the N-terminus of beta 10 is protected by the surrounding hydrophobic and hydrophilic residues which cooperate positively with the central backbone HB and make this HB highly strong. The intimate relationship between the effective strength of protein backbone HB and water revealed here should be considered when performing mechanical analysis for protein conformational changes.
- Published
- 2018
9. Isotope shift calculations for D lines of stable and short-lived lithium nuclei
- Author
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Bing-Ming Xu, Geng-Hua Yu, Wei Yang, Peng-Yi Zhao, and Xiao-Ling Zhu
- Subjects
Physics ,Isotope ,General Physics and Astronomy ,chemistry.chemical_element ,Configuration interaction ,01 natural sciences ,010305 fluids & plasmas ,Ion ,chemistry ,0103 physical sciences ,Lithium ,Physics::Atomic Physics ,Atomic physics ,010306 general physics - Abstract
The isotope shifts (ISs) for the 2s2S1/2 to 2p2P J (J = 1/2, 3/2) transitions of the lithium nuclei including the stable and short-lived isotopes are calculated based on the multi-configuration Dirac–Hartree–Fock method and the relativistic configuration interaction approach. The results are in good agreement with the previous theoretical and experimental results within a deviation less than 0.05%. The methods used here could be applied to the IS calculations for other heavier Li-like ions and few-electron systems.
- Published
- 2016
10. Numerical investigation of a coupled moving boundary model of radial flow in low-permeable stress-sensitive reservoir with threshold pressure gradient
- Author
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Liu, Wen-Chao, primary, Liu, Yue-Wu, additional, Niu, Cong-Cong, additional, Han, Guo-Feng, additional, and Wan, Yi-Zhao, additional
- Published
- 2016
- Full Text
- View/download PDF
11. Groove-type channel enhancement-mode AlGaN/GaN MIS HEMT with combined polar and nonpolar AlGaN/GaN heterostructures
- Author
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Ming Xiao, Xiaoling Duan, Yi Zhao, Jincheng Zhang, Yue Hao, and Jing Ning
- Subjects
010302 applied physics ,Electron mobility ,Materials science ,business.industry ,Transconductance ,Transistor ,General Physics and Astronomy ,02 engineering and technology ,High-electron-mobility transistor ,Semiconductor device ,021001 nanoscience & nanotechnology ,01 natural sciences ,Subthreshold slope ,law.invention ,Threshold voltage ,law ,0103 physical sciences ,Optoelectronics ,Breakdown voltage ,0210 nano-technology ,business - Abstract
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 mS/mm, and subthreshold slope of 85 mV/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 (V B) 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.
- Published
- 2016
12. Covalent intermolecular interaction of the nitric oxide dimer (NO) 2
- Author
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Zhang, Hui, primary, Zheng, Gui-Li, additional, Lv, Gang, additional, Geng, Yi-Zhao, additional, and Ji, Qing, additional
- Published
- 2015
- Full Text
- View/download PDF
13. Initial conformation of kinesin's neck linker
- Author
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Geng, Yi-Zhao, primary, Ji, Qing, additional, Liu, Shu-Xia, additional, and Yan, Shi-Wei, additional
- Published
- 2014
- Full Text
- View/download PDF
14. Covalent intermolecular interaction of the nitric oxide dimer (NO) 2
- Author
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Gang Lv, Hui Zhang, Gui-Li Zheng, Qing Ji, and Yi-Zhao Geng
- Subjects
Quantitative Biology::Biomolecules ,chemistry.chemical_compound ,Chemical bond ,Chemistry ,Covalent bond ,Chemical physics ,Dimer ,General Physics and Astronomy ,Molecule ,Antibonding molecular orbital ,Pi bond ,Bond order ,Natural bond orbital - Abstract
Covalent bonds arise from the overlap of the electronic clouds in the internucleus region, which is a pure quantum effect and cannot be obtained in any classical way. If the intermolecular interaction is of covalent character, the result from direct applications of classical simulation methods to the molecular system would be questionable. Here, we analyze the special intermolecular interaction between two NO molecules based on quantum chemical calculation. This weak intermolecular interaction, which is of covalent character, is responsible for the formation of the NO dimer, (NO)(2), in its most stable conformation, a cis conformation. The natural bond orbital (NBO) analysis gives an intuitive illustration of the formation of the dimer bonding and antibonding orbitals concomitant with the breaking of the pi bonds with bond order 0.5 of the monomers. The dimer bonding is counteracted by partially filling the antibonding dimer orbital and the repulsion between those fully or nearly fully occupied nonbonding dimer orbitals that make the dimer binding rather weak. The direct molecular mechanics (MM) calculation with the UFF force fields predicts a trans conformation as the most stable state, which contradicts the result of quantum mechanics (QM). The lesson from the investigation of this special system is that for the case where intermolecular interaction is of covalent character, a specific modification of the force fields of the molecular simulation method is necessary.
- Published
- 2015
15. Design and optimization of a SiC thermal emitter/absorber composed of periodic microstructures based on a non-linear method
- Author
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Yi Zhao, Wei-Jie Wang, Ceji Fu, Zhenguo Zhao, and Haijing Zhou
- Subjects
Materials science ,business.industry ,Phonon ,General Physics and Astronomy ,chemistry.chemical_compound ,Optics ,chemistry ,Thermal ,Silicon carbide ,Polariton ,Radiative transfer ,business ,Absorption (electromagnetic radiation) ,Photonic crystal ,Common emitter - Abstract
Spectral and directional control of thermal emission based on excitation of confined electromagnetic resonant modes paves a viable way for the design and construction of microscale thermal emitters/absorbers. In this paper, we present numerical simulation results of the thermal radiative properties of a silicon carbide (SiC) thermal emitter/absorber composed of periodic microstructures. We illustrate different electromagnetic resonant modes which can be excited with the structure, such as surface phonon polaritons, magnetic polaritons and photonic crystal modes, and the process of radiation spectrum optimization based on a non-linear optimization algorithm. We show that the spectral and directional control of thermal emission/absorption can be efficiently achieved by adjusting the geometrical parameters of the structure. Moreover, the optimized spectrum is insensitive to 3% dimension modification.
- Published
- 2015
16. Influence of compressive strain on the incorporation of indium in InGaN and InAlN ternary alloys
- Author
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Xiaowei Zhou, JunShuai Xue, Yue Hao, Jincheng Zhang, Shengrui Xu, and Yi Zhao
- Subjects
Materials science ,Strain (chemistry) ,business.industry ,General Physics and Astronomy ,chemistry.chemical_element ,Heterojunction ,Chemical vapor deposition ,Nitride ,chemistry ,Aluminium ,Sapphire ,Optoelectronics ,Ternary operation ,business ,Indium - Abstract
In order to investigate the influence of compressive strain on indium incorporation in InAlN and InGaN ternary nitrides, InAlN/GaN heterostructures and InGaN films were grown by metal?organic chemical vapor deposition. For the heterostructures, different compressive strains are produced by GaN buffer layers grown on unpatterned and patterned sapphire substrates thanks to the distinct growth mode; while for the InGaN films, compressive strains are changed by employing AlGaN templates with different aluminum compositions. By various characterization methods, we find that the compressive strain will hamper the indium incorporation in both InAlN and InGaN. Furthermore, compressive strain is conducive to suppress the non-uniform distribution of indium in InGaN ternary alloys.
- Published
- 2015
17. Initial conformation of kinesin's neck linker
- Author
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Qing Ji, Shiwei Yan, Shu-Xia Liu, and Yi-Zhao Geng
- Subjects
Chemistry ,FOS: Physical sciences ,General Physics and Astronomy ,Biomolecules (q-bio.BM) ,Condensed Matter - Soft Condensed Matter ,Head rotation ,Hydrophobic effect ,Molecular dynamics ,Quantitative Biology - Biomolecules ,Biological Physics (physics.bio-ph) ,Docking (molecular) ,FOS: Biological sciences ,Biophysics ,Soft Condensed Matter (cond-mat.soft) ,Kinesin ,Physics - Biological Physics ,Linker - Abstract
How ATP binding initiates the docking process of kinesin's neck linker is a key question in understanding kinesin mechanism. It is believed that the formation of an extra turn structure by the first three amino acids of neck linker (LYS325, THR326, ILE327 in 2KIN) is crucial for initiating the docking process. But the initial conformation of neck linker (specially the three amino acids of the extra turn) and the neck linker docking initiation mechanism remain unclear. By using molecular dynamics method, we investigate the initial conformation of kinesin's neck linker in the docking process. We find that, in the initial state of NL docking process, NL still has interactions with {\beta}0 and forms a conformation similar to the "cover-neck bundle" structure proposed by Hwang et al. [Structure 2008, 16(1): 62-71]. From this initial structure, the docking of the "cover-neck bundle" structure can be achieved. The motor head provides a forward force on the initial cover-neck bundle structure through ATP-induced rotation. This force, together with the hydrophobic interaction of ILE327 with the hydrophobic pocket on the motor head, drives the formation of the extra turn and initiates the neck linker docking process.
- Published
- 2014
18. Retarded thermal oxidation of strained Si substrate
- Author
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Yi Shi, Yi Zhao, Zhou-Wei Yang, Xiaoyu Tang, and Jiabao Sun
- Subjects
Thermal oxidation ,Materials science ,Si substrate ,law ,Ultimate tensile strength ,Uniaxial tension ,General Physics and Astronomy ,Integrated circuit ,Composite material ,law.invention - Abstract
Strained Si is recognized as a necessary technology booster for modern integrated circuit technology. However, the thermal oxidation behaviors of strained Si substrates are not well understood yet despite their importance. In this study, we for the first time experimentally find that all types of strained Si substrates (uniaxial tensile, uniaxial compressive, biaxial tensile, and biaxial compressive) show smaller thermal oxidation rates than an unstrained Si substrate. The possible mechanisms for these retarded thermal oxidation rates in strained Si substrates are also discussed.
- Published
- 2014
19. Improvement in a -plane GaN crystalline quality using wet etching method
- Author
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Pei-Shui Cui, Xing Chen, Jincheng Zhang, JunShuai Xue, Hui-Juan Wen, Cao Rongtao, Wei Ha, Yi Zhao, Shuai Zhang, and Shengrui Xu
- Subjects
Diffraction ,Stress (mechanics) ,Full width at half maximum ,Photoluminescence ,Materials science ,business.industry ,Etching (microfabrication) ,Phonon ,General Physics and Astronomy ,Optoelectronics ,Dislocation ,Epitaxy ,business - Abstract
Nonpolar (110) GaN films are grown on the etched a-plane GaN substrates via metalorganic vapor phase epitaxy. High-resolution X-ray diffraction analysis shows great decreases in the full width at half maximum of the samples grown on etched substrates compared with those of the sample without etching, both on-axis and off-axis, indicating the reduced dislocation densities and improved crystalline quality of these samples. The spatial mapping of the E2 (high) phonon mode demonstrates the smaller line width with a black background in the wing region, which testifies the reduced dislocation densities and enhanced crystalline quality of the epitaxial lateral overgrowth areas. Raman scattering spectra of the E2 (high) peaks exhibit in-plane compressive stress for all the overgrowth samples, and the E2 (high) peaks of samples grown on etched substrates shift toward the lower frequency range, indicating the relaxations of in-plane stress in these GaN films. Furthermore, room temperature photoluminescence measurement demonstrates a significant decrease in the yellow-band emission intensity of a-plane GaN grown on etched templates, which also illustrates the better optical properties of these samples.
- Published
- 2014
20. Effect of ultrathin GeOxinterfacial layer formed by thermal oxidation on Al2O3capped Ge
- Author
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Han Le, Shengkai Wang, Xiong Zhang, Xue Baiqing, Yi Zhao, Honggang Liu, and Wang-Ran Wu
- Subjects
Thermal oxidation ,Electron mobility ,Materials science ,Passivation ,business.industry ,General Physics and Astronomy ,chemistry.chemical_element ,Equivalent oxide thickness ,Thermal treatment ,Subthreshold slope ,Oxygen ,chemistry ,Optoelectronics ,business ,Layer (electronics) - Abstract
We propose a modified thermal oxidation method in which an Al2O3 capping layer is used as an oxygen blocking layer (OBL) to form an ultrathin GeOx interfacial layer, and obtain a superior Al2O3/GeOx/Ge gate stack. The GeOx interfacial layer is formed in oxidation reaction by oxygen passing through the Al2O3 OBL, in which the Al2O3 layer could restrain the oxygen diffusion and suppress the GeO desorption during thermal treatment. The thickness of the GeOx interfacial layer would dramatically decrease as the thickness of Al2O3 OBL increases, which is beneficial to achieving an ultrathin GeOx interfacial layer to satisfy the demand for small equivalent oxide thickness (EOT). In addition, the thickness of the GeOx interfacial layer has little influence on the passivation effect of the Al2O3/Ge interface. Ge (100) p-channel metal–oxide–semiconductor field-effect transistors (pMOSFETs) using the Al2O3/GeOx/Ge gate stacks exhibit excellent electrical characteristics; that is, a drain current on-off (Ion/Ioff) ratio of above 1×104, a subthreshold slope of ~ 120 mV/dec, and a peak hole mobility of 265 cm2/Vs are achieved.
- Published
- 2014
21. Radiation-induced robust oscillation and non-Gaussian fluctuation
- Author
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Liu, Bo, primary, Yan, Shi-Wei, additional, and Geng, Yi-Zhao, additional
- Published
- 2011
- Full Text
- View/download PDF
22. Improvement in a-plane GaN crystalline quality using wet etching method.
- Author
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Rong-Tao, Cao, Sheng-Rui, Xu, Jin-Cheng, Zhang, Yi, Zhao, Jun-Shuai, Xue, Wei, Ha, Shuai, Zhang, Pei-Shui, Cui, Hui-Juan, Wen, and Xing, Chen
- Subjects
ORGANOMETALLIC compounds ,X-ray diffraction ,PHONON scattering ,PHOTOLUMINESCENCE ,DISLOCATION etching ,CRYSTALLINE polymers - Abstract
Nonpolar (112̄0) GaN films are grown on the etched a-plane GaN substrates via metalorganic vapor phase epitaxy. High-resolution X-ray diffraction analysis shows great decreases in the full width at half maximum of the samples grown on etched substrates compared with those of the sample without etching, both on-axis and off-axis, indicating the reduced dislocation densities and improved crystalline quality of these samples. The spatial mapping of the E
2 (high) phonon mode demonstrates the smaller line width with a black background in the wing region, which testifies the reduced dislocation densities and enhanced crystalline quality of the epitaxial lateral overgrowth areas. Raman scattering spectra of the E2 (high) peaks exhibit in-plane compressive stress for all the overgrowth samples, and the E2 (high) peaks of samples grown on etched substrates shift toward the lower frequency range, indicating the relaxations of in-plane stress in these GaN films. Furthermore, room temperature photoluminescence measurement demonstrates a significant decrease in the yellow-band emission intensity of a-plane GaN grown on etched templates, which also illustrates the better optical properties of these samples. [ABSTRACT FROM AUTHOR]- Published
- 2014
- Full Text
- View/download PDF
23. Effect of ultrathin GeOx interfacial layer formed by thermal oxidation on Al2O3 capped Ge.
- Author
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Le, Han, Sheng-Kai, Wang, Xiong, Zhang, Bai-Qing, Xue, Wang-Ran, Wu, Yi, Zhao, and Hong-Gang, Liu
- Subjects
THERMAL oxidation (Materials science) ,INTERFACIAL bonding ,PASSIVATION ,METAL oxide semiconductor field-effect transistors ,RESTRAINING orders ,DESORPTION - Abstract
We propose a modified thermal oxidation method in which an Al
2 O3 capping layer is used as an oxygen blocking layer (OBL) to form an ultrathin GeOx interfacial layer, and obtain a superior Al2 O3 /GeOx /Ge gate stack. The GeOx interfacial layer is formed in oxidation reaction by oxygen passing through the Al2 O3 OBL, in which the Al2 O3 layer could restrain the oxygen diffusion and suppress the GeO desorption during thermal treatment. The thickness of the GeOx interfacial layer would dramatically decrease as the thickness of Al2 O3 OBL increases, which is beneficial to achieving an ultrathin GeOx interfacial layer to satisfy the demand for small equivalent oxide thickness (EOT). In addition, the thickness of the GeOx interfacial layer has little influence on the passivation effect of the Al2 O3 /Ge interface. Ge (100) p-channel metal–oxide–semiconductor field-effect transistors (pMOSFETs) using the Al2 O3 /GeOx /Ge gate stacks exhibit excellent electrical characteristics; that is, a drain current on-off (Ion /Ioff ) ratio of above 1×104 , a subthreshold slope of ∼ 120 mV/dec, and a peak hole mobility of 265 cm2 /V·s are achieved. [ABSTRACT FROM AUTHOR]- Published
- 2014
- Full Text
- View/download PDF
24. Increased performance of an organic light-emitting diode by employing a zinc phthalocyanine based composite hole transport layer.
- Author
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Run-Da, Guo, Shou-Zhen, Yue, Peng, Wang, Yu, Chen, Yi, Zhao, and Shi-Yong, Liu
- Subjects
ORGANIC light emitting diodes ,LIGHT emitting diodes ,ZINC phthalocyanine ,ABSORPTION spectra ,CURRENT density (Electromagnetism) - Abstract
We demonstrate that the electroluminescent performances of organic light-emitting diodes are significantly improved by employing a zinc phthalocyanine (ZnPc)-based composite hole transport layer (c-HTL). The optimum ris-(8-hydroxyquinoline)aluminum (Alq
3 )-based organic light-emitting diode with a c-HTL exhibits a lower turn-on voltage of 2.8 V, a higher maximum current efficiency of 3.40 cd/A and a higher maximum power efficiency of 1.91 lm/W, which are superior to those of the conventional device (turn-on voltage of 3.8 V, maximum current efficiency of 2.60 cd/A, and maximum power efficiency of 1.21 lm/W). We systematically studied the effects of different kinds of N'-diphenyl-N,N'-bis(1-naphthyl)(1,1'-biphenyl)-4,4'diamine (NPB):ZnPc c-HTL. Meanwhile, we also investigate their mechanisms different from that in the case of using ZnPc as buffer layer. The specific analysis is based on the absorption spectra of the hole transporting material and current density—voltage characteristics of the corresponding hole-only devices. [ABSTRACT FROM AUTHOR]- Published
- 2013
- Full Text
- View/download PDF
25. Protection-against-water-attack determined difference between strengths of backbone hydrogen bonds in kinesin’s neck zipper region.
- Author
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Jing-Yu Qin, Yi-Zhao Geng, Gang Lü, Qing Ji, and Hai-Ping Fang
- Subjects
- *
HYDROGEN bonding , *KINESIN , *MOLECULAR dynamics , *WATER , *HYDROPHOBIC interactions - Abstract
Docking of the kinesin’s neck linker (NL) to the motor domain is the key force-generation process of the kinesin. In this process, NL’s β10 portion forms four backbone hydrogen bonds (HBs) with the motor domain. These backbone hydrogen bonds show big differences in their effective strength. The origins of these strength differences are still unclear. Using molecular dynamics method, we investigate the stability of the backbone HBs in explicit water environment. We find that the strength differences of these backbone HBs mainly arise from their relationships with water molecules which are controlled by arranging the surrounding residue sidechains. The arrangement of the residues in the C-terminal part of β10 results in the existence of the water-attack channels around the backbone HBs in this region. Along these channels the water molecules can directly attack the backbone HBs and make these HBs relatively weak. In contrast, the backbone HB at the N-terminus of β10 is protected by the surrounding hydrophobic and hydrophilic residues which cooperate positively with the central backbone HB and make this HB highly strong. The intimate relationship between the effective strength of protein backbone HB and water revealed here should be considered when performing mechanical analysis for protein conformational changes. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
26. Isotope shift calculations for D lines of stable and short-lived lithium nuclei.
- Author
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Geng-Hua Yu, Peng-Yi Zhao, Bing-Ming Xu, Wei Yang, and Xiao-Ling Zhu
- Subjects
- *
LITHIUM isotopes , *PHASE transitions , *RELATIVISTIC configuration interaction , *ELECTRONS , *STANDARD deviations - Abstract
The isotope shifts (ISs) for the 2s2S1/2 to 2p2PJ (J = 1/2, 3/2) transitions of the lithium nuclei including the stable and short-lived isotopes are calculated based on the multi-configuration Dirac–Hartree–Fock method and the relativistic configuration interaction approach. The results are in good agreement with the previous theoretical and experimental results within a deviation less than 0.05%. The methods used here could be applied to the IS calculations for other heavier Li-like ions and few-electron systems. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
27. Groove-type channel enhancement-mode AlGaN/GaN MIS HEMT with combined polar and nonpolar AlGaN/GaN heterostructures.
- Author
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Xiao-Ling Duan, Jin-Cheng Zhang, Ming Xiao, Yi Zhao, Jing Ning, and Yue Hao
- Subjects
HETEROSTRUCTURES ,GALLIUM nitride ,NITRIDES ,CRYSTALS ,SUPERLATTICES - Abstract
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 mS/mm, and subthreshold slope of 85 mV/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 (V
B ) 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. [ABSTRACT FROM AUTHOR]- Published
- 2016
- Full Text
- View/download PDF
28. Numerical investigation of a coupled moving boundary model of radial flow in low-permeable stress-sensitive reservoir with threshold pressure gradient.
- Author
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Wen-Chao Liu, Cong-Cong Niu, Guo-Feng Han, Yi-Zhao Wan, and Yue-Wu Liu
- Subjects
BOUNDARY value problems ,SOIL permeability ,FLUID dynamic measurements ,POROSITY ,DARCY'S law ,ELASTOPLASTICITY ,GREEN'S functions - Abstract
The threshold pressure gradient and formation stress-sensitive effect as the two prominent physical phenomena in the development of a low-permeable reservoir are both considered here for building a new coupled moving boundary model of radial flow in porous medium. Moreover, the wellbore storage and skin effect are both incorporated into the inner boundary conditions in the model. It is known that the new coupled moving boundary model has strong nonlinearity. A coordinate transformation based fully implicit finite difference method is adopted to obtain its numerical solutions. The involved coordinate transformation can equivalently transform the dynamic flow region for the moving boundary model into a fixed region as a unit circle, which is very convenient for the model computation by the finite difference method on fixed spatial grids. By comparing the numerical solution obtained from other different numerical method in the existing literature, its validity can be verified. Eventually, the effects of permeability modulus, threshold pressure gradient, wellbore storage coefficient, and skin factor on the transient wellbore pressure, the derivative, and the formation pressure distribution are analyzed respectively. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
29. Retarded thermal oxidation of strained Si substrate.
- Author
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Jia-Bao Sun, Xiao-Yu Tang, Zhou-Wei Yang, Yi Shi, and Yi Zhao
- Subjects
THERMAL oxidation (Materials science) ,INTEGRATED circuits ,COMPLEMENTARY metal oxide semiconductors ,PERMITTIVITY ,SILICON oxide ,METAL oxide semiconductors - Abstract
Strained Si is recognized as a necessary technology booster for modern integrated circuit technology. However, the thermal oxidation behaviors of strained Si substrates are not well understood yet despite their importance. In this study, we for the first time experimentally find that all types of strained Si substrates (uniaxial tensile, uniaxial compressive, biaxial tensile, and biaxial compressive) show smaller thermal oxidation rates than an unstrained Si substrate. The possible mechanisms for these retarded thermal oxidation rates in strained Si substrates are also discussed. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
30. Measurement of integral diffraction coefficients of crystals on beamline 4B7 of Beijing Synchrotron Radiation Facility.
- Author
-
Jia, Yang, Xin, Gan, Yang, Zhao, Ming, Cui, Tuo, Zhu, Yi, Zhao, Li, Sun, Lei, Zheng, Fen, Yan, Zhi, Hu, Min, Wei, Ji, Zhang, and, Yan, and Rong, Yi
- Subjects
OPTICAL diffraction ,SYNCHROTRON radiation ,NUCLEAR facilities ,X-ray spectroscopy ,HIGH temperature plasmas ,POLYETHYLENE terephthalate - Abstract
Integral diffraction coefficients of the crystal are the essential data of a crystal spectrometer which is extensively used to measure quantitative x-ray spectra of high temperature plasmas in kilo-electron-volt region. An experimental method has been developed to measure the integral diffraction coefficients of crystals on beamline 4B7 of Beijing Synchrotron Radiation Facility. The integral diffraction coefficients of several crystals including polyethylene terephthalate (PET), thallium acid phthalate (TlAP) and rubidium acid phthalate (RAP) crystals have been measured in the x-ray energy range 2100-5600 eV and compared with the calculations of the 'Darwin Prins' and the 'Mosaic' models. It is shown that the integral diffraction coefficients of these crystals are between the calculations of the 'Darwin Prins' and the 'Mosaic' models, but more close to the 'Darwin Prins' model calculations. [ABSTRACT FROM AUTHOR]
- Published
- 2011
- Full Text
- View/download PDF
31. Coherent beam combining of hybrid phase control in master oscillator-power amplifier configuration.
- Author
-
Xiao, Wang, Pu, Zhou, Yan, Ma, Hao, Ma, Xiao, Xu, Ze, Liu, and, Jin, and Yi, Zhao
- Subjects
COHERENCE (Physics) ,PHASE equilibrium ,OSCILLATIONS ,POWER amplifiers ,LASER beams ,PARALLEL algorithms ,STOCHASTIC processes ,BRILLOUIN scattering - Abstract
A novel scalable architecture for coherent beam combining with hybrid phase control involving passive phasing and active phasing in master oscillator-power amplifier configuration is presented. Wide-linewidth mutually injected passive phasing fibre laser arrays serve as master oscillators for the power amplifiers, and the active phasing using stochastic parallel gradient descent algorithm is induced. Wide-linewidth seed laser can suppress the stimulated Brillouin scattering effectively and improve the output power of the fibre laser amplifier, while hybrid phase control provides a robust way for in-phase mode coherent beam combining simultaneously. Experiment is performed by active phasing fibre laser amplifiers with passive phasing fibre ring laser array seed lasers. Power encircled in the main-lobe increases 1.57 times and long-exposure fringe contrast is obtained to be 78% when the system evolves from passive phasing to hybrid phasing. [ABSTRACT FROM AUTHOR]
- Published
- 2010
- Full Text
- View/download PDF
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