40 results on '"Qi Ji"'
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2. The crystal structure of poly[bis(μ2-1,4-bi(1-imidazolyl)benzene-κ2N:N′)bis(μ2-4,4′-methylenebis(3-hydroxy-2-naphthoate)-κ2O:O′)cobalt(II)], C35H24CoN4O6
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Qi Ji, Wang Shu-Ying, and Chu Jin-Feng
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2289669 ,Physics ,QC1-999 ,Crystallography ,QD901-999 - Abstract
C35H24CoN4O6, monoclinic, P21/n (no. 14), a = 11.444(2) Å, b = 11.648(2) Å, c = 21.478(4) Å, β = 97.05(3)°, V = 2841.5(10) Å3, Z = 4, Rgt(F) = 0.0849, wRref(F2) = 0.1393, T = 153(2) K.
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- 2023
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3. Editorial: Advances in Polarimetry and Ellipsometry: Fundamentals and Applications
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Haofeng Hu, Hao Jiang, Qi Ji, and Jingping Zhu
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polarimetry ,polarimetric imaging ,ellipsometry ,polarization ,Mueller matrix ,Stokes vector ,Physics ,QC1-999 - Published
- 2022
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4. Double exchange interaction in Mn-based topological kagome ferrimagnet
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Jiameng Wang, Arthur Ernst, Victor N. Antonov, Qi Jiang, Haoji Qian, Deyang Wang, Jiefeng Cao, Fangyuan Zhu, Shan Qiao, and Mao Ye
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Astrophysics ,QB460-466 ,Physics ,QC1-999 - Abstract
Abstract Recently discovered Mn-based kagome materials, such as RMn6Sn6 (R = rare-earth element), exhibit the coexistence of topological electronic states and long-range magnetic order, offering a platform for studying quantum phenomena. However, understanding the electronic and magnetic properties of these materials remains incomplete. Here, we investigate the electronic structure and magnetic properties of GdMn6Sn6 using x-ray magnetic circular dichroism, photoemission spectroscopy, and theoretical calculations. We observe localized electronic states from spin frustration in the Mn-based kagome lattice and induced magnetic moments in the nonmagnetic element Sn experimentally, which originate from the Sn- $$p$$ p and Mn- $$d$$ d orbital hybridization. Our calculations also reveal ferromagnetic coupling within the kagome Mn-Mn layer, driven by double exchange interaction. This work provides insights into the mechanisms of magnetic interaction and magnetic tuning in the exploration of topological quantum materials.
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- 2024
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5. L10 FePd-based perpendicular magnetic tunnel junctions with 65% tunnel magnetoresistance and ultralow switching current density
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Deyuan Lyu, Jenae E. Shoup, Ali T. Habiboglu, Qi Jia, Pravin Khanal, Brandon R. Zink, Yang Lv, Bowei Zhou, Daniel B. Gopman, Weigang Wang, and Jian-Ping Wang
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Physics ,QC1-999 - Abstract
L10 FePd is increasingly recognized as a potential candidate for magnetic tunnel junctions (MTJs), yet there remains room for enhancing device performance. In this work, we fabricated fully-integrated L10 FePd-based perpendicular MTJ devices and achieved a significant increase in tunnel magnetoresistance, reaching ∼65%, compared to the previous record of 25%. Notably, we observed bi-directional switching with a low switching current density of about 1.4 × 105 A/cm2, which outperforms the typical spin-transfer torque (STT) MTJ by about one order of magnitude. We propose two possible mechanisms to elucidate the switching process and associated device performance: (1) The voltage-controlled exchange coupling-driven switching of the bottom CoFeB layer; (2) The STT-driven switching of the exchange-coupled L10 FePd–CoFeB composite. While additional research is necessary, these findings may further advance the integration of L10 FePd into spintronic devices, potentially enabling low-energy memory and logic technologies.
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- 2024
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6. High-harmonic generation in CdTe with ultra-low pump intensity and high photon flux
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Zhe Long, Hang Yang, Kan Tian, Linzhen He, Rui Qin, Zi-Yu Chen, Qi Jie Wang, and Houkun Liang
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Astrophysics ,QB460-466 ,Physics ,QC1-999 - Abstract
Abstract An ultra-low pump intensity and high photon flux have been long pursuits of high harmonic generation (HHG) in solids. However, there is lack of a criterion to identify a pristine solid material exhibiting such characteristics. Here, we report systematic investigation into HHG from a cadmium telluride (CdTe) bulk crystal with a flat band dispersion near the Fermi level which leads to a large density of states. The measured pump intensity for the 31st harmonics (229 nm) is only 75 GW/cm2, one order of magnitude lower than that of other pristine crystals including two-dimensional materials reported so far. A comparative measurement shows CdTe has two-to-three orders of magnitude stronger HHG than silicon does, and high HHG yields in the ultraviolet region compared to GaSe. A high photon flux of ~ 6 × 1012 photons/s (5th −8th) with a robust long-time sustainability is obtained. This work offers a route towards compact vacuum ultraviolet laser sources.
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- 2023
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7. Magic wavelengths for the 6S-7P transition of cesium atoms
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Jiandong Bai, Yang Liu, Shaofeng Fan, Shuo Liu, Wenyuan Liu, Qi Jie, Yijun Li, and Junmin Wang
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Dynamic polarizability ,Optical dipole trap ,Magic wavelength ,Robustness ,Physics ,QC1-999 - Abstract
For the trapped pre-cooled atoms in an optical dipole trap (ODT), the magic-wavelength ODT can eliminate the differential light shift of the transition between two atomic states, so that the transition frequency between the two states is the same as that of atoms in the free space, which is of great significance for improving the experimental repetition rate and reducing the atomic decoherence in the fields of cold atom physics, quantum optics, and precision measurement. Here we calculate the dynamic polarizabilities of cesium 6S ground state and 7P excited state by using the multi-level model for the ODT with laser wavelength from 1200 to 2000 nm. The magic wavelengths of ODT are obtained for the linearly and circularly polarized laser beams at the intersection of dynamic polarizabilities of two atomic states. Furthermore, we analyze the robustness of the magic trapping conditions and the feasibility of the experimental operation near the telecom C-band wavelength.
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- 2023
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8. Type‐II Dirac Nodal Lines in a Double‐Kagome‐Layered Semimetal
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Yongqing Cai, Jianfeng Wang, Yuan Wang, Zhanyang Hao, Yixuan Liu, Liang Zhou, Xuelei Sui, Zhicheng Jiang, Shengjie Xu, Han Ge, Xiao‐Ming Ma, Chengcheng Zhang, Zecheng Shen, Yichen Yang, Qi Jiang, Zhengtai Liu, Mao Ye, Dawei Shen, Yi Liu, Shengtao Cui, Le Wang, Cai Liu, Junhao Lin, Bing Huang, Liusuo Wu, Jincheng Zhuang, Hongtao He, Wenqing Zhang, Jia‐Wei Mei, and Chaoyu Chen
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nonsaturating magnetoresistance ,quasi‐1D band ,spin Berry curvature ,type‐II Dirac nodal line semimetal ,van Hove singularity ,Electric apparatus and materials. Electric circuits. Electric networks ,TK452-454.4 ,Physics ,QC1-999 - Abstract
Abstract Lorentz‐violating type‐II Dirac nodal line semimetals (DNLSs), hosting curves of band degeneracy formed by two dispersion branches with the same sign of slope, represent a novel state of matter. While being studied extensively in theory, convincing experimental evidence of type‐II DNLSs remain elusive. Recently, vanadium‐based kagome materials have emerged as a fertile ground to study the interplay between lattice symmetry and band topology. This work studies the low‐energy band structure of double‐kagome‐layered CsV8Sb12 and identifies it as a scarce type‐II DNLS protected by mirror symmetry. This work observes multiple DNLs consisting of type‐II Dirac cones close to or almost at the Fermi level via angle‐resolved photoemission spectroscopy (ARPES), which provides an electronic explanation for the nonsaturating magnetoresistance effect as observed. First‐principles theory analyses show that spin‐orbit coupling only opens a small gap, resulting in effectively gapless ARPES spectra, yet generating large spin Berry curvature. These type‐II DNLs, together with the interaction between a low‐energy van Hove singularity and quasi‐one‐dimensional band as observed in the same material, suggest CsV8Sb12 as an ideal platform for exploring novel transport properties.
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- 2023
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9. Highly effective mineralization of acetic acid wastewater via catalytic ozonation over the promising MnO2/γ-Al2O3 catalyst
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Erhao Gao, Ruiyun Meng, Qi Jin, Shuiliang Yao, Zuliang Wu, Jing Li, and Erdeng Du
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Acetic acid wastewater ,Mineralization ,Catalytic ozonation ,MnO2/γ-Al2O3 ,·OH radical ,Physics ,QC1-999 ,Chemistry ,QD1-999 - Abstract
The complete mineralization of acetic acid in wastewater through a biodegradation process is difficult due to the α-position methyl coordinated with the carboxyl group, and this work explored the oxidation performance of acetic acid by catalytic ozonation with metal oxides supported on γ-Al2O3. It was found that MnO2/γ-Al2O3 catalyst achieved superior mineralization performance to Co/Fe/CeOx supported on γ-Al2O3 for acetic acid wastewater treatment. The effects of MnO2 loading, catalyst dosage, acetic acid concentration, O3 concentration, ozonation temperature, and initial pH value of the acetic acid solution were investigated. Typically, the mineralization of acetic acid over 1.0 wt.% MnO2/γ-Al2O3 catalyst was as high as 88.4% after 300 min ozonation of 1.0 g·L‒1 acetic acid at 25 °C with the highest energy efficiency around 15 g·kWh‒1. By contrast, the mineralization of acetic acid could only reach 43.2% in the absence of the catalyst, with an energy efficiency of 5.1 g·kWh−1. Radical quenchers and indicated that ·OH radical, O2− species originated from ozone played an important role in the catalytic ozonation of acetic acid into CO2 and H2O. Besides, the catalytic ozonation mechanism of acetic acid over MnO2/γ-Al2O3 was carefully proposed based on the in situ DRIFTS results.
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- 2023
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10. Simultaneous Determination of Sodium Pentachlorophenolate and Its Metabolites in Swine Samples
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Qi Jia, Miao Cui, Meiling Li, Yuncheng Li, Fanbing Meng, Yanyang Xu, Yongzhong Qian, Xue Yan, and Jing Qiu
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swine samples ,sodium pentachlorophenolate ,metabolites ,residue detection ,chromatography tandem mass spectrometry ,Physics ,QC1-999 ,Chemistry ,QD1-999 - Abstract
Pentachlorophenol (PCP) is a persistent organic pollutant usually present in the form of sodium salts (PCP-Na) that has been banned for many years, but it can still be detected in animal food. The present study established a method of detecting PCP-Na and its metabolites—tetrachlorocatechol (TCC), pentachlorophenol acetate (PCP-acetate), and pentachloroanisole (PCA)—in swine samples (pork, fat, liver, heart, lungs and kidney), simultaneously using liquid chromatography-tandem mass spectrometry (LC-MS/MS) and gas chromatography-tandem mass spectrometry (GC-MS/MS) based on the modified QuEChERS pre-treatment method. The validation results exhibited a good sensitivity with limits of quantitation (LOQs) of 1 μg/kg–2 μg/kg. The recoveries of spiked samples were in the range of 60.5–119.9%, with a relative standard deviation (RSD) between replicates (n = 5) of between 0.70% and 12.06%.
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- 2023
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11. A 206-nm all-solid-state deep-ultraviolet laser with 291 MW peak power
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Qiandong Ran, Joel Stephen Short, Qi Jie Wang, and Hao Li
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deep-ultraviolet ,all-solid-state laser ,sum frequency generation ,206 nm ,sub-picosecond DUV laser ,high-power ultrafast lasers ,Physics ,QC1-999 - Abstract
We successfully demonstrate the generation of an all-solid-state deep-ultraviolet (DUV) laser at 206 nm through the fifth (4 + 1)-harmonic generation using a 197-W, 10-kHz, 1.2-ps, 1,030-nm Yb:YAG laser. The DUV laser delivers 180 μJ–582 fs pulses with a peak power of 291 MW, which, to the best of our knowledge, is the highest peak power at 206 nm ever produced by all-solid-state kHz DUV laser sources driven at 1 μm wavelength. This corresponds to one order of magnitude improvement from early state-of-the-art record reported in the literature.
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- 2023
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12. High-order mode interaction structure for a W-band CW sheet beam extended interaction klystron
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Qi Jin, Zhihui Geng, Rui Zhang, Bingchuan Xie, Shuzhong Wang, Yunfeng Liao, Xiudong Yang, and Shouxi Xu
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Physics ,QC1-999 - Abstract
To solve the problem of mode competition in high-order working modes, this paper presents a fast design method based on the TM31-2π mode for the dumbbell shaped extended interaction cavity. Based on the equivalent circuit theory, the high-frequency characteristics of the structure are studied. In addition, we propose a W-band continuous wave sheet beam extended interaction klystron high-frequency circuit. The circuit was driven by a 20 kV and 0.85 A sheet electron beam, with a 3.2 × 0.3 mm2 section. The beam was focused by a 0.8 T permanent magnet system. The high-frequency system adopts five dumbbell shaped five-gap cavities, and the output system adopts a symmetrical output waveguide. The 3D particle-in-cell simulation shows that more than 1.5 kW power can be obtained at an input power of 0.12 W, and the electron efficiency and gain are 9.2% and 41.2 dB, respectively.
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- 2022
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13. Study on phase demodulation algorithm of fiber optic pressure sensor based on nonlinear differential equation
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Fei Feng, Qi Jia, Chunhua Liu, and Kaibai Yue
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Physics ,QC1-999 - Abstract
Fiber optic Fabry–Pérot sensors have been widely developed with unique advantages, such as ease of reuse, resistance to electromagnetic interference, light weight, and their ability to work in extreme environments. There are many demodulation methods that can be applied to fiber optic Fabry–Pérot sensors, including the intensity demodulation method, spectral demodulation, and the phase carrier method, but these demodulation methods cannot meet the requirements that take into account range, speed, and dynamic and static demodulation capabilities. In view of these problems, this paper uses nonlinear differential equations to solve the problem of simultaneous measurement of a large number of ranges and dynamic and static parameters. The measuring interferometer in the demodulation module was built using a polarizing interferometer, which avoids the difficulty in optical wedge processing when using a Fizeau interferometer. Regarding the problems of high and low signal-to-noise ratios of the generated signal, for the problem that the introduction of dispersion in the crystal causes the demodulation result of the traditional demodulation method to be wrong, a nonlinear differential equation is proposed to achieve the correct demodulation of the fiber optic sensor: the slow demodulation speed problem. This paper designs the acquisition, transmission, and processing system based on digital signal processing and a field-programmable gate array, which provide a hardware platform for real-time demodulation. Finally, experiments to test the resolution, linearity, stability, and repeatability of the interferometer were carried out on the designed demodulation system.
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- 2022
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14. Topological transitions with an imaginary Aubry-André-Harper potential
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Bofeng Zhu, Li-Jun Lang, Qiang Wang, Qi Jie Wang, and Y. D. Chong
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Physics ,QC1-999 - Abstract
We study one-dimensional lattices with imaginary-valued Aubry-André-Harper (AAH) potentials. Such lattices can host edge states with purely imaginary eigenenergies, which differ from the edge states of the Hermitian AAH model and are stabilized by a non-Hermitian particle-hole symmetry. The edge states arise when the period of the imaginary potential is a multiple of four lattice constants. They are topological in origin, and can manifest on domain walls between lattices with different modulation periods and phases, as predicted by a bulk polarization invariant. Interestingly, the edge states persist and remain localized even if the gap in the real spectrum closes. These features can be used in laser arrays to select topological lasing modes under spatially extended pumping.
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- 2023
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15. A large field-of-view metasurface for complex-amplitude hologram breaking numerical aperture limitation
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Mu Yongheng, Zheng Mengyao, Qi Jiaran, Li Hongmei, and Qiu Jinghui
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complex amplitude metasurface ,field-of-view ,metasurface hologram ,numerical aperture ,Physics ,QC1-999 - Abstract
Owing to the potential to manipulate simultaneously amplitude and phase of electromagnetic wave, complex-amplitude holographic metasurfaces (CAHMs) can achieve improved image-reconstruction quality compared with amplitude-only and phase-only ones. However, prevailing design methods based on Huygens–Fresnel theory for CAHMs, e.g., Rayleigh–Sommerfeld diffraction theory (RSDT), restrict acquisition of high-precision reconstruction in a large field of view (FOV), especially in the small numerical aperture (NA) scenario. To this end, a CAHM consisting of Sine-shaped meta-atoms is proposed in a microwave region, enabled by a novel complex amplitude retrieval method, to realize large FOV holograms while breaking the large NA limitation. Calculations and full-wave simulations demonstrate that the proposed method can achieve superior-quality holograms, even for nonparaxial holograms in a relatively small NA scenario, thus improving FOV and aperture utilization efficiency of CAHMs. The reconstruction comparison of a complex multi-intensity field distribution between CAHM prototypes designed by our method and by RSDT further confirms this point. We also compare both theoretically and experimentally the CAHM by our method with the phase-only metasurface by weighted Gerchberg–Saxton algorithm. Superior-quality holograms with suppressed background noise and relieved deformation, promised by the extra amplitude manipulation freedom, is witnessed. Finally, due to its wavelength irrelevance, the proposed method is applicable to the entire spectrum, spanning from microwave to optics.
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- 2020
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16. SU(3) Spin–Orbit Coupled Rotating Bose–Einstein Condensate Subject to a Gradient Magnetic Field
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Guang-Ping Chen, Pu Tu, Chang-Bing Qiao, Jin-Xia Zhu, Qi Jia, and Xiao-Fei Zhang
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Bose–Einstein condensate ,SU(3) spin–orbit coupling ,gradient magnetic field ,rotation ,GP equation ,Physics ,QC1-999 - Abstract
We consider a harmonically trapped rotating spin-1 Bose–Einstein condensate with SU(3) spin–orbit coupling subject to a gradient magnetic field. The effects of SU(3) spin–orbit coupling, rotation, and gradient magnetic field on the ground-state structure of the system are investigated in detail. Our results show that the interplay among SU(3) spin–orbit coupling, rotation, and gradient magnetic field can result in a variety of ground states, such as a vortex ring and clover-type structure. The numerical results agree well with our variational analysis results.
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- 2021
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17. Theoretical and Experimental Investigations on the Ultra-Low-Frequency Broadband of Quasi-Static Metamaterials
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Haixia Liu, Weitao He, Lixia Li, and Qi Jia
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elastic metamaterial ,local resonance ,finite element method ,vibration control ,Technology ,Engineering (General). Civil engineering (General) ,TA1-2040 ,Biology (General) ,QH301-705.5 ,Physics ,QC1-999 ,Chemistry ,QD1-999 - Abstract
This paper proposes an I-shaped radial elastic metamaterial with ultra-low-frequency broadband characteristics and studies the propagation characteristics of elastic waves in their quasi-static state. Through the calculation of the dispersion relationship, the frequency response function, and the eigenmode displacement field, it is found that the ultra-low-frequency wide band gap can be generated in the quasi-static metamaterial. The wide band gap is mainly caused by modal transitions. The equivalent mass–spring model reveals the modal changes of the I-shaped radial elastic metamaterial under the surface constraints. Furthermore, by studying the directional vibration displacement field of the finite period structure, it is demonstrated that the mechanism of the ultra-low-frequency broadband (0
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- 2022
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18. A Fast Method for the Simultaneous Analysis of 26 Beta-Agonists in Swine Muscle with a Multi-Functional Filter by Ultra-High Performance Liquid Chromatography-Tandem Mass Spectrometry
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Lin Zhang, Qi Jia, Guangqin Liao, Yongzhong Qian, and Jing Qiu
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beta-agonists ,swine muscle ,ultra-high performance liquid chromatography-tandem mass spectrometry ,multi-functional filter ,QuEChERS ,Physics ,QC1-999 ,Chemistry ,QD1-999 - Abstract
A rapid and simplified sample preparation method was developed for the simultaneous determination of 26 beta-agonists in swine muscle using a multi-functional filter (MFF) based on quick, easy, cheap, effective, rugged, and safe methods (QuEChERS). MFF integrated the cleanup and filter procedures, thereby significantly improving the efficiency of sample preparation compared with traditional solid-phase extraction. The sample was processed via enzymatic hydrolysis, purified with the optimized MFF containing 150 mg magnesium sulfate, 50 mg PSA, and 50 mg C18, and then analyzed using ultra-high performance liquid chromatography-tandem mass spectrometry. All procedures can be completed in 6.5 h. Good linearity (R2 > 0.99) was detected in all analytes. The recoveries ranged from 71.2% to 118.6%, with relative standard deviations (RSDs) of less than 18.37% in all spiked concentrations. The limits of detection (LOD) and the limits of quantitation (LOQ) were 0.01–0.10 and 0.10–0.50 μg/kg, respectively. The decision limit (CCα) and detection capacity (CCβ) values fluctuated in the range of 3.44–25.71 and 6.38–51.21 μg/kg, respectively. This method is a good alternative for detecting beta-agonist residues in swine muscle and can be successfully applied to the national risk monitoring of agro-product quality and safety in China.
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- 2022
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19. Coupling Effects of Yaw Damper and Wheel-Rail Contact on Ride Quality of Railway Vehicle
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Hai Zhang, Xiangrui Ran, Xiugang Wang, Fengtao Lin, and Qi Jiang
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Physics ,QC1-999 - Abstract
The ride quality of the railway vehicle is not only affected by the wheel-rail contact geometry but also by the yaw damper. In order to explore this variation law, an equivalent parameter model of the yaw damper was established based on the internal characteristics of the yaw damper, which is both accurate and efficient. Then, considering the influence of wheel wear and wheel-rail contact geometry, ride quality of the railway vehicle under different parameters of yaw damper and wheel-rail contact parameters was analysed. The results show that the wheel-rail contact points are scattered on the wheel profile after the wheel wears out, and the equivalent conicity also tends to increase with the increasing operating mileage. The distribution of ride quality space is sensitive to the change of equivalent conicity. In the low equivalent conicity area, the expansion rate of excellent ride quality space is faster. In the high equivalent conicity area, the expansion rate of qualified ride quality space is faster. Appropriate additional stiffness which is oil stiffness in parallel with structural damping in the equivalent parameter model of the yaw damper can improve the vehicle ride quality. The lateral ride quality is influenced obviously with the condition of the damping of the yaw damper being less than 440 kN·s·m−1. Properly reducing the joint stiffness of the yaw damper could reduce the influence of characteristic parameters of the yaw damper and equivalent conicity of the wheel-rail contact on vehicle lateral ride quality. The optimized characteristic parameters of the yaw damper are used in the actual vehicle test, and the ride quality is effectively improved.
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- 2021
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20. Plasmonic nano-arrays for ultrasensitive bio-sensing
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Jiang Jing, Wang Xinhao, Li Shuang, Ding Fei, Li Nantao, Meng Shaoyu, Li Ruifan, Qi Jia, Liu Qingjun, and Liu Gang Logan
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lspr ,nano-array ,plasmonics ,sensing ,spr ,Physics ,QC1-999 - Abstract
Surface plasmon resonance (SPR) and localized SPR (LSPR) effects have been shown as the principles of some highlysensitive sensors in recent decades. Due to the advances in nano-fabrication technology, the plasmon nano-array sensors based on SPR and LSPR phenomena have been widely used in chemical and bioloical analysis. Sensing with surface-enhanced field and sensing for refractive index changes are able to identify the analytes quantitatively and qualitatively. With the newly developed ultrasensitive plasmonic biosensors, platforms with excellent performance have been built for various biomedical applications, including point-of-care diagnosis and personalized medicine. In addition, flexible integration of plasmonics nano-arrays and combining them with electrochemical sensing have significantly enlarged the application scenarios of the plasmonic nano-array sensors, as well as improved the sensing accuracy.
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- 2018
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21. Numerical Analysis of an Upstream Tailings Dam Subjected to Pond Filling Rates
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Tan Manh Do, Jan Laue, Hans Mattsson, and Qi Jia
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excess pore water pressure ,pond filling rates ,upstream tailings dam ,numerical analysis ,Technology ,Engineering (General). Civil engineering (General) ,TA1-2040 ,Biology (General) ,QH301-705.5 ,Physics ,QC1-999 ,Chemistry ,QD1-999 - Abstract
One of the challenges in upstream tailings dam projects is to ensure the allowable rate of deposition of tailings in the pond (i.e., pond filling rate) while maintaining the stability of the dam. This is due to the fact that an upstream tailings dam is constructed by placing dikes on top of previously deposited soft tailings, which could lead to a decrease in dam stability because of the build-up of excess pore water pressure. The main purpose of this work is to investigate the effects of pond filling rates on excess pore water pressure and the stability of an upstream tailings dam by a numerical study. A finite element software was used to simulate the time-dependent pond filling process and staged dam construction under various pond filling rates. As a result, excess pore water pressure increased in each raising phase and decreased in the subsequent consolidation phase. However, some of the excess pore water pressure remained after every consolidation phase (i.e., the build-up of excess pore water pressure), which could lead to a potentially critical situation in the stability of the dam. In addition, the remaining excess pore water pressure varied depending on the pond filling rates, being larger for high filling rates and smaller for low filling rates. It is believed that the approach used in this study could be a guide for dam owners to keep a sufficiently high pond filling rate but still ensure the desirable stability of an upstream tailings dam.
- Published
- 2021
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22. Preparation and microwave absorption properties of ZnFe2O4/polyaniline/graphene oxide composite
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Yue Qiao, Junping Xiao, Qi Jia, Liying Lu, and Huili Fan
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Physics ,QC1-999 - Abstract
In this work, a new kind of ternary composite (ZnFe2O4(cube)/Polyaniline/Graphene oxide composite) with good absorbing property was prepared by a simple in-situ polymerization. The chemical composition and morphology of ZnFe2O4 and composite were characterized by FT-IR, XRD, XPS, SEM. The electromagnetic absorption property of composite was investigated by means of vector network analyzer. The results indicated that the dielectric loss of ternary composite was dominated by the Debye dipolar relaxation. The maximum absorbing loss of ternary composite was −58.0 dB at 9.5 GHz, and the bandwidth exceeding −10 dB was 3.91 GHz with the absorber thickness of 3.29 mm.
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- 2019
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23. Mechanism and Investment Analysis of Recycling Gasoline Solvent with Mineral Powder for Asphalt Cleaning
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Fusong Wang, Hechuan Li, Qi Jiang, Chao Yang, Yuanyuan Li, and Shaopeng Wu
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gasoline consumption ,mineral powder ,asphalt binder ,solvent ,environmental impacts ,Technology ,Engineering (General). Civil engineering (General) ,TA1-2040 ,Biology (General) ,QH301-705.5 ,Physics ,QC1-999 ,Chemistry ,QD1-999 - Abstract
Gasoline is widely used as a powerful organic solvent to remove asphalt residuals in road engineering applications; however, it is also known as a non-renewable fuel resource. This research aims to employ mineral powder to mitigate the consumption of gasoline in asphalt binder cleaning process, and evaluate its mechanism, environmental and economic benefits. Based on X-Ray Diffraction (XRD) spectra, X-Ray Fluorescence (XRF) spectra and Atomic Absorption Spectroscopy (AAS) detection, the microstructure and composition of mineral powder was investigated after adsorbing asphalt components from gasoline solution. Fourier Transform Infrared spectra (FTIR) were used to calculate the adsorption efficiency. Moreover, the assessments of environmental and economic impacts of investigated approach were evaluated quantitatively. The results indicated that the interactions between mineral powder and asphalt binder have not changed the crystal phase, and the rough interface of mineral powder could adsorb approximately 4% asphalt binder from the gasoline solution according to the detection of Zn. The comparative analysis, regarding cost-effectiveness and environmental impacts, demonstrated that once 1 kg asphalt adsorbed by mineral powder, recycling gasoline with mineral powder, could reduce costs by 80% (CNY 57.10), energy use by 97% (352.88 MJ) and equivalent CO2 emission by 93% (23.95 kg).
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- 2020
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24. Quantifying the uncertainty introduced by internal climate variability in projections of Canadian crop production
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Budong Qian, Qi Jing, Ward Smith, Brian Grant, Alex J Cannon, and Xuebin Zhang
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climate change impacts ,crop production ,crop modelling ,internal climate variability ,uncertainty ,Environmental technology. Sanitary engineering ,TD1-1066 ,Environmental sciences ,GE1-350 ,Science ,Physics ,QC1-999 - Abstract
Internal climate variability (ICV) is one of the major sources of uncertainty in climate projections, yet it is seldom quantified for projections of crop production. Our study focuses on quantifying the uncertainty due to ICV in projections of crop productions in Canada. We utilize climate scenarios from two large ensembles (LEs, CanESM2-LE and CanRCM4-LE with 25 members each) as inputs to the crop models in the Decision Support System for Agrotechnology Transfer. We simulate crop yields for canola, maize and spring wheat under the future climates of four global warming levels. The coefficient of variation (CV) of the projected crop production across the LE members is used to quantify the uncertainty related to ICV and this is compared with the CVs generated using the 20 GCMs in the Coupled Model Intercomparison Project Phase 5 (CMIP5). Crop production in Canada could increase with global warming, e.g. spring wheat production could increase by up to 21% at the warming level of 3.0 °C. The projections often produce larger uncertainty associated with the GCMs than from ICV at all warming levels above 2.0 °C. The results from an asymptotic test for the equality of CVs show a significant difference in CVs of projections of canola production between CanESM2-LE/CanRCM4-LE and CMIP5 for the warming level of 3.0 °C. However, the test results do not indicate a significant difference among the ensembles at all four warming levels for maize and spring wheat. The uncertainty due to ICV is often comparable to that associated with GCMs at the warming level of 1.5 °C, e.g. a CV of 6.0 and 6.4% for CanESM2-LE and CanRCM4-LE and 6.6% for CMIP5 in the projections of spring wheat production. We conclude there is a need to account for uncertainty related to ICV in projections of Canadian crop production, especially at lower warming levels.
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- 2020
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25. Spatial structure of lasing modes in wave-chaotic semiconductor microcavities
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Stefan Bittner, Kyungduk Kim, Yongquan Zeng, Qi Jie Wang, and Hui Cao
- Subjects
microcavity lasers ,wave-dynamical chaos ,open systems ,semiconductor lasers ,Science ,Physics ,QC1-999 - Abstract
We present experimental and numerical studies of broad-area semiconductor lasers with chaotic ray dynamics. The emission intensity distributions at the cavity boundaries are measured and compared to ray tracing simulations and numerical calculations of the passive cavity modes. We study two different cavity geometries, a D-cavity and a stadium, both of which feature fully chaotic ray dynamics. While the far-field distributions exhibit fairly homogeneous emission in all directions, the emission intensity distributions at the cavity boundary are highly inhomogeneous, reflecting the non-uniform intensity distributions inside the cavities. The excellent agreement between experiments and simulations demonstrates that the intensity distributions of wave-chaotic semiconductor lasers are primarily determined by the cavity geometry. This is in contrast to conventional Fabry–Perot broad-area lasers for which the intensity distributions are to a large degree determined by the nonlinear interaction of the lasing modes with the semiconductor gain medium.
- Published
- 2020
- Full Text
- View/download PDF
26. Theoretical design of mid-infrared interband cascade lasers in SiGeSn system
- Author
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Yuan Li, Zhigang Song, Zeyu Li, Greg Sun, Chuan Seng Tan, Weijun Fan, and Qi Jie Wang
- Subjects
interband cascade laser ,group-IV materials ,eight-band k⋅p method ,Science ,Physics ,QC1-999 - Abstract
By carefully analyzing the latest composition-dependent parameters of SiGeSn alloys, we come to realize that this system could provide type-II energy band alignment at direct bandgap condition. The discovery inspires us to explore the mid-infrared interband cascade laser (ICL) in SiGeSn system. Based on the eight-band k ⋅ p model, we theoretically design three schemes of ICL, in which the active region and the carrier injectors are optimized simultaneously. Afterward, the properties of TE-mode optical gain spectrums and differential gain are investigated individually for each scheme. Furthermore, the spontaneous emission spectrums and radiative current density are also calculated. Our theoretical results indicate that the active region composed of double-electron and triple-hole quantum wells has the best gain performance, reaching 660 cm ^−1 for a single period of the ICL under 7.8 × 10 ^18 cm ^−3 injected electron density. This work opens up another type of infrared lasers that can be developed from the group-IV system, offering a new pathway to achieving the monolithic integration in Si photonics.
- Published
- 2020
- Full Text
- View/download PDF
27. Silicon-on-insulator with hybrid orientations for heterogeneous integration of GaN on Si (100) substrate
- Author
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Runchun Zhang, Beiji Zhao, Kai Huang, Tiangui You, Qi Jia, Jiajie Lin, Shibin Zhang, Youquan Yan, Ailun Yi, Min Zhou, and Xin Ou
- Subjects
Physics ,QC1-999 - Abstract
Heterogeneous integration of materials pave a new way for the development of the microsystem with miniaturization and complex functionalities. Two types of hybrid silicon on insulator (SOI) structures, i.e., Si (100)-on-Si (111) and Si (111)-on-Si (100), were prepared by the smart-cut technique, which is consist of ion-slicing and wafer bonding. The precise calculation of the lattice strain of the transferred films without the epitaxial matching relationship to the substrate was demonstrated based on X-ray diffraction (XRD) measurements. The XRD and Raman measurement results suggest that the transferred films possess single crystalline quality. With a chemical mechanical polishing (CMP) process, the surface roughness of the transferred thin films can be reduced from 5.57 nm to 0.30 nm. The 4-inch GaN thin film epitaxially grown on the as-prepared hybrid SOI of Si (111)-on-Si (100) by metalorganic chemical vapor deposition (MOCVD) is of improved quality with a full width at half maximum (FWHM) of 672.54 arcsec extracted from the XRD rocking curve and small surface roughness of 0.40 nm. The wafer-scale GaN on Si (111)-on-Si (100) can serve as a potential platform for the one chip integration of GaN-based high electron mobility transistors (HEMT) or photonics with the Si (100)-based complementary metal oxide semiconductor (CMOS).
- Published
- 2018
- Full Text
- View/download PDF
28. Crystal structure of (1′R,2′S,4′R,6′S)-4,6-dihydroxy-1′,8′,8′-trimethyl-3-(3-methylbutanoyl)-4′,8′,6′,1′,7,2′-hexahydro-1H-4′,6′-methanoxanthene-8-carbaldehyde, C23H30O5
- Author
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Huang Nian, Zhou Lang, Zhang Yin-Ju, Chen Fa-Ju, Li Qi-Ji, and Zhao Neng-Wu
- Subjects
2361000 ,Physics ,QC1-999 ,Crystallography ,QD901-999 - Abstract
C23H30O5, orthorhombic, P212121 (no. 19), a = 9.5489(10) Å, b = 11.1430(10) Å, c = 18.8931(10) Å, V = 2010.29(3) Å3, Z = 4, Rgt(F) = 0.0293, wRref(F2) = 0.0763, T = 100.0(2) K.
- Published
- 2024
- Full Text
- View/download PDF
29. Effects of Channel Outlet Configuration and Dimple/Protrusion Arrangement on the Blade Trailing Edge Cooling Performance
- Author
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Qi Jing, Yonghui Xie, and Di Zhang
- Subjects
turbine blade trailing edge ,cooling ,outlet configuration ,dimple ,protrusion ,flow structure ,overall thermal performance ,Technology ,Engineering (General). Civil engineering (General) ,TA1-2040 ,Biology (General) ,QH301-705.5 ,Physics ,QC1-999 ,Chemistry ,QD1-999 - Abstract
The trailing edge regions of high-temperature gas turbine blades are subjected to extremely high thermal loads and are affected by the external wake flow during operation, thus creating great challenges in internal cooling design. With the development of cooling technology, the dimple and protrusion have attracted wide attention for its excellent performance in heat transfer enhancement and flow resistance reduction. Based on the typical internal cooling structure of the turbine blade trailing edge, trapezoidal cooling channels with lateral extraction slots are modeled in this paper. Five channel outlet configurations, i.e., no second passage (OC1), radially inward flow second passage (OC2), radially outward flow second passage (OC3), top region outflow (OC4), both sides extractions (OC5), and three dimple/protrusion arrangements (all dimple, all protrusion, dimple−protrusion staggered arrangement) are considered. Numerical investigations are carried out, within the Re range of 10,000−100,000, to analyze the flow structures, heat transfer distributions, average heat transfer and friction characteristics and overall thermal performances in detail. The results show that the OC4 and OC5 cases have high heat transfer levels in general, while the heat transfer deterioration occurs in the OC1, OC2, and OC3 cases. For different dimple/protrusion arrangements, the protrusion case produces the best overall thermal performance. In conclusion, for the design of trailing edge cooling structures with lateral slots, the outlet configurations of top region outflow and both sides extractions, and the all protrusion arrangement, are recommended.
- Published
- 2019
- Full Text
- View/download PDF
30. Climate change impacts on Canadian yields of spring wheat, canola and maize for global warming levels of 1.5 °C, 2.0 °C, 2.5 °C and 3.0 °C
- Author
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Budong Qian, Xuebin Zhang, Ward Smith, Brian Grant, Qi Jing, Alex J Cannon, Denise Neilsen, Brian McConkey, Guilong Li, Barrie Bonsal, Hui Wan, Li Xue, and Jun Zhao
- Subjects
agriculture ,Canada ,climate change ,climate targets ,crop yields ,crop models ,Environmental technology. Sanitary engineering ,TD1-1066 ,Environmental sciences ,GE1-350 ,Science ,Physics ,QC1-999 - Abstract
Science-based assessments of climate change impacts on cropping systems under different levels of global warming are essential for informing stakeholders which global climate targets and potential adaptation strategies may be effective. A comprehensive evaluation of climate change impacts on Canada’s crop production under different levels of global warming is currently lacking. The DayCent, DNDC and DSSAT models were employed to estimate changes in crop yield and production for three prominent crops including spring wheat, canola and maize in current agricultural regions of Canada. Four warming scenarios with global mean temperature changes of 1.5 °C, 2.0 °C, 2.5 °C and 3.0 °C above the pre-industrial level were investigated. Climate scenarios from 20 Global Climate Models, included in the Coupled Model Intercomparison Project Phase 5 and downscaled with a multivariate quantile mapping bias correction method, were used to drive the crop simulation models. Simulated yield changes demonstrate a potentially positive impact on spring wheat and canola yields at all four temperature levels, particularly when shifting planting date is considered in the simulations. There was less consensus for the currently utilized short-season maize cultivars, as yields were only projected to increase by DNDC compared to a slight decrease by DayCent and a slight increase up to 2.5 °C followed by a decrease at 3.0 °C by DSSAT. These findings indicate that climate at the global warming levels up to 3.0 °C above the pre-industrial level could be beneficial for crop production of small grains in Canada. However, these benefits declined after warming reached 2.5 °C.
- Published
- 2019
- Full Text
- View/download PDF
31. An Investigation on the Forced Convection of Al2O3-water Nanofluid Laminar Flow in a Microchannel Under Interval Uncertainties
- Author
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Zhaoli Zheng, Qi Jing, Yonghui Xie, and Di Zhang
- Subjects
Al2O3-water nanofluid ,microchannel ,convection heart transfer ,uncertainty ,interval analysis ,Chebyshev polynomial approximation ,Technology ,Engineering (General). Civil engineering (General) ,TA1-2040 ,Biology (General) ,QH301-705.5 ,Physics ,QC1-999 ,Chemistry ,QD1-999 - Abstract
Nanofluids are regarded as an effective cooling medium with tremendous potential in heat transfer enhancement. In reality, nanofluids in microchannels are at the mercy of uncertainties unavoidably due to manufacturing error, dispersion of physical properties, and inconstant operating conditions. To obtain a deeper understanding of forced convection of nanofluids in microchannels, uncertainties are suggested to be considered. This paper studies numerically the uncertain forced convection of Al2O3-water nanofluid laminar flow in a grooved microchannel. Uncertainties in material properties and geometrical parameter are considered. The uncertainties are represented by interval variables. By employing Chebyshev polynomial approximation, interval method (IM) is presented to estimate the uncertain thermal performance and flow behavior of the forced convection problem. The validation of the accuracy and effectiveness of IM are demonstrated by a comparison with the scanning method (SM). The variation of temperature, velocity, and Nusselt number are obtained under different interval uncertainties. The results show that the uncertainties have remarkable influences on the simulated thermal performance and flow behavior.
- Published
- 2019
- Full Text
- View/download PDF
32. Effect of roughness on perpendicular magnetic anisotropy in (Co90Fe10/Pt)n superlattices
- Author
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Jinjun Qiu, Zhaoliang Meng, Yi Yang, Ji Feng Ying, Qi Jia Yap, and Guchang Han
- Subjects
Physics ,QC1-999 - Abstract
Superlattice [Co90Fe10(0.21)/Pt(0.23)]n (unit in nm) with the repeat cycles n ranging from 3 to 30 were studied. Both effective anisotropy (Keff) and PMA constant (KU) reached a maximum at n=8. When the 3 nm Pt underlayer was deposited at low energy condition, the Keff and KU of (CoFe/Pt)8 are 4.0 and 6.1 Merg/cc, respectively. On the other hand, the Keff and KU increased to 6.8 and 9.7 Merg/cc, respectively, when the Pt underlayer deposited at high energy condition. As the n increases, the surface roughness monotonously increases and d111 inside the superlattice layers increase and relax from bottom to top part. The interface roughness and relaxation in superlattice reduce the PMA considerably.
- Published
- 2016
- Full Text
- View/download PDF
33. Determination of the electric field induced anisotropy change in sub-100 nm perpendicularly magnetized devices
- Author
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Jiancheng Huang, Michael Tran, Sze Ter Lim, Aihong Huang, Chuyi Yang, Qi Jia Yap, and Guchang Han
- Subjects
Physics ,QC1-999 - Abstract
We measure the voltage or electric field (EF) modulated change in anisotropy using two methods on the same nanometer sized device: 1) Directly using the area of the hard axis magnetization loop and 2) Indirectly using the switching field distribution method. Both methods yield similar values of efficiency. With the indirect method, the efficiency derived from the thermal stability was found to be more consistent than that from the anisotropy field. Our data also suggests that memory devices that rely solely on EF effects may benefit from larger device sizes.
- Published
- 2016
- Full Text
- View/download PDF
34. Crystal structure of nonaaqua[bis(μ2-pyridine-2,4,6-tricarboxylato- κ3O,N,O:(O')dilutetium(III)]trihydrate, Lu2(H2O)9(ptc)2·3H2O, C16H28Lu2N2O24
- Author
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Zhu Hong-Lin and Qi Jin-Li
- Subjects
Physics ,QC1-999 ,Crystallography ,QD901-999 - Abstract
C16H28Lu2N2O24, triclinic, P1̄ (no. 2), a = 7.602(2) Å, b = 10.417(2) Å, c = 17.374(4) Å, α = 92.32(3)°, β = 92.08(3)°, γ = 95.74(3)°, V = 1366.7 Å3, Z = 2, Rgt(F) = 0.0489, wRref(F2) = 0.1229, T = 293 K.
- Published
- 2013
- Full Text
- View/download PDF
35. Development of our laser fusion integration simulation
- Author
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Li Jinghong, Zhai Chuanlei, Li Shuanggui, Li Xin, Zheng Wudi, Yong Heng, Zeng Qinghong, Hang Xudeng, Qi Jin, Yang Rong, Cheng Juan, Song Peng, Gu Peijun, Zhang Aiqing, An Hengbin, Xu Xiaowen, Guo Hong, Cao Xiaolin, Mo Zeyao, Pei Wenbing, Jiang Song, and Zhu Shao-ping
- Subjects
Physics ,QC1-999 - Abstract
In the target design of the Inertial Confinement Fusion (ICF) program, it is common practice to apply radiation hydrodynamics code to study the key physical processes happening in ICF process, such as hohlraum physics, radiation drive symmetry, capsule implosion physics in the radiation-drive approach of ICF. Recently, many efforts have been done to develop our 2D integrated simulation capability of laser fusion with a variety of optional physical models and numerical methods. In order to effectively integrate the existing codes and to facilitate the development of new codes, we are developing an object-oriented structured-mesh parallel code-supporting infrastructure, called JASMIN. Based on two-dimensional three-temperature hohlraum physics code LARED-H and two-dimensional multi-group radiative transfer code LARED-R, we develop a new generation two-dimensional laser fusion code under the JASMIN infrastructure, which enable us to simulate the whole process of laser fusion from the laser beams' entrance into the hohlraum to the end of implosion. In this paper, we will give a brief description of our new-generation two-dimensional laser fusion code, named LARED-Integration, especially in its physical models, and present some simulation results of holhraum.
- Published
- 2013
- Full Text
- View/download PDF
36. Crystal structure of 13-hydroxy-8(9)-abieten-20-oic acid, C20H32O3
- Author
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Liu Ya-Hua, Li Qi-Ji, Li Ji-Xin, Zhang Qi-Long, and Pan Lu-Tai
- Subjects
Physics ,QC1-999 ,Crystallography ,QD901-999 - Abstract
C20H32O3, trigonal, P3121 (no. 152), a = 14.420(2) Å, c = 31.927(6) Å, V = 5749.8 Å3, Z = 12, Rgt(F) = 0.0539, wRref(F2) = 0.1223, T = 293 K.
- Published
- 2012
- Full Text
- View/download PDF
37. Crystal structure of 1'-methoxy-7a',8-dimethyldecahydro-1'H[7,9amethanocyclohepta[ c]pyran-4,4'-isobenzofuran]-1,9(3H,4aH)-dione, C21H30O5
- Author
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Zou Juan, Li Qi-Ji, Zhang Qi-Long, Zhang Jing-Jie, and Pan Lu-Tai
- Subjects
Physics ,QC1-999 ,Crystallography ,QD901-999 - Abstract
C21H30O5, monoclinic, P21 (no. 4), a = 7.396(1) Å, b = 11.650(2) Å, c = 11.440(2) Å, β = 108.155(4)°, V = 936.7 Å3, Z = 2, Rgt(F) = 0.0398, wRref(F2) = 0.1032, T = 293 K.
- Published
- 2013
- Full Text
- View/download PDF
38. Crystal structure of 2,16-dien-1,15-dion-6,7-seco-7,20-olide-ent-kaur-6-al, C20H22O5
- Author
-
Pan Lu-Tai, Li Qi-Ji, Liu Ya-Hua, Zhang Jing-Jie, and Zhang Qi-Long
- Subjects
Physics ,QC1-999 ,Crystallography ,QD901-999 - Published
- 2012
- Full Text
- View/download PDF
39. Refinement of the crystal structure of 3,20-epoxy-6b,15b- diacetoxy- ent-kaurene-1,7-dione, C24H30O7
- Author
-
Zhang Jing-Jie, Li Qi-Ji, Zhang Qi-Long, and Pan Lu-Tai
- Subjects
Physics ,QC1-999 ,Crystallography ,QD901-999 - Published
- 2011
- Full Text
- View/download PDF
40. Crystal structure of 17-(3-methyl-2-butenoyl)-entkaurane- 7a,16b-diol, C25H40O4
- Author
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Zhao Neng-Wu, Li Qi-Ji, Zhang Jing-Jie, Zhang Qi-Long, and Pan Lu-Tai
- Subjects
Physics ,QC1-999 ,Crystallography ,QD901-999 - Published
- 2011
- Full Text
- View/download PDF
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