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91.
Ambisonics is a series of spatial sound reproduction system based on spatial harmonics decomposition and each order approximation of sound field. Ambisonics signals are originally intended for loudspeakers reproduction. By
using head-related transfer functions (HRTFs) filters, binaural Ambisonics converts the Ambisonics signals for static or dynamic headphone reproduction. In present work, the performances of static and dynamic binaural Ambisonics
reproduction are evaluated and compared. The mean binaural pressure errors across target source directions are first analyzed. Then a virtual source localization experiment is conducted, and the localization performances are
evaluated by analyzing the percentages of front-back and up-down confusion, the mean angle error and discreteness in the localization results. The results indicate that binaural Ambsonics reproduction with insufficiently high order (for example, 5-10 order) is unable to recreate correct high-frequency magnitude spectra in binaural pressures, resulting in degradation in localization for static reproduction. Because dynamic localization cue is included, dynamic binaural Ambisoncis reproduction yields obviously better localization performance than static reproduction with the same order. Even a 3-order dynamic binaural Ambisoncis reproduction exhibits appropriate localizations performance. 相似文献
92.
采用ELSD-HPLC、UV-HPLC及薄层鉴别法,对毛冬青药材其根、茎、细枝、叶的成分进行对比研究。试验结果显示,毛冬青植物茎、细枝、叶脂溶性成分与根的相似度分别为100%、75%、75%;茎、细枝水溶性成分与根的相似度均为100%。因此认为从化学成分上看,毛冬青药用部位可以从根扩大至根茎或茎。更多还原 相似文献
93.
94.
本文描述了一台场效应管超再生核四极共振谱仪的工作原理和性能;谱仪的振荡检波级是作者研制的一个频率覆盖范围较宽、灵敏度较高的场效应管(FET)超再生振荡检波器。文中还给出用本谱仪显示、记录的部分化学样品中的35Cl核和37Cl核的核四极共振(NQR)谱,并对使用场效应管的超再生振荡检波器的灵敏度作初步探讨。 相似文献
95.
Hongwei Zhao Yanqiu Zhang Li Lixiang Xin Geng Haiming Yang Weimin Zhou Chengguo Sun Baigang An 《中国化学快报》2021,32(1):140-145
Both nitrogen-doping feature and pore structure are critical factors for developing nitrogen-doped carbons based catalysts with a high performance toward oxygen reduction reaction(ORR).Herein,a simple one-step CVD of acetylene and acetonitrile vapor method using silanized SBA-15 as a template has been developed to synthesize an ordered porous carbon(OPC) with dual nitrogen-doped interfaces.The optimized sample as prepared with the CVD of 4 h at 750℃ contains two types of ordered mesopores that one type is the ordered cylindrical pores inheriting from the pores of SBA-15 and has a pore width of4.0~5.0 nm,the other type is the ordered quasi-hexagonal pores with a width of 3.0~4.0 nm produced by etching the pore walls of SBA-15.These two types of pores whose pore walls are built by the nitrogen doped carbon layers resulted by the CVD and thus it actually makes the dual nitrogen-doped interfaced OPC(DN-OPC).Meanwhile,DN-OPC contains a few of micropores and a large SSA of 1430 m~2/g.This dualordered pores and dual nitrogen-doped interfaces cannot only facilitate mass transport but also utilize the active sites of DN-OPC for ORR.Therefore,as metal-free ORR catalyst,DN-OPC exhibits a good activity close to commercial Pt/C catalyst,and an excellent durability and methanol tolerance. 相似文献
96.
Yushu Deng Shihao Wang Shiqi Zheng Haiming Li Haitao Jian Xiaoqi Tang 《Entropy (Basel, Switzerland)》2022,24(8)
This paper addresses the asynchronous stabilization problem of two typical stochastic switching systems, i.e., dual switching systems and semi-Markov jump systems. By dual switching, it means that the systems contain both deterministic and stochastic switching dynamics. New stability criteria are firstly proposed for these two switched systems, which can well handle the asynchronous phenomenon. The conditional expectation of Lyapunov functions is allowed to increase during some unmatched interval to reduce the conservatism. Next, we present numerically testable asynchronous controller design methods for the dual switching systems. The proposed method is suitable for the situation where the asynchronous modes come from both inaccurate mode detection and time varying delay. Meanwhile, the transition probabilities are both uncertain and partly accessible. Finally, novel asynchronous controller design methods are proposed for the semi-Markov jump systems. The sojourn time of the semi-Markov jump systems can have both lower and upper bounds, which could be more practical than previous scenarios. Examples are utilized to demonstrate the effectiveness of the proposed methods. 相似文献
97.
98.
J.J. Pan FengQing Zhou Haiming Wu Xiangdong Qiu Ruby Chen Yousheng Wu Henry He Eric Zhang Chunmeng Wu 《光学学报》2003,23(Z1)
A compact variable optical attenuator, covering C and L bands with over 50 dB attenuation range, is realized using a single liquid crystal cell with a tilted fused silica coating compensating the cell's small residual birefringence. 相似文献
99.
Haiming Wang 《Fiber and Integrated Optics》1991,10(3):245-256
A novel phase-perturbation method as well as an experimental system were established to study the deviation of the laser diode (LD) far-field intensity distribution from the ideal Gaussian. An analytical expression of the LD far-field intensity distribution and a numerical method based on the Monte Carlo calculation were developed to fit the measured results. The loss of the LD to the single-mode fiber (SMF) coupling system caused by this kind of deviation of the LD far-field intensity distribution was quantitatively analyzed. 相似文献
100.
A capillary zone electrophoresis method with HP-β-CD as chiral selector was established for the chiral separation of four stereoisomers of 1-(4-hydroxy-3-methoxy)-phenyl-2-[4-(1,2,3-trihydroxy-propyl)-2-methoxy]-phenoxy-1,3-propandiol for the first time, which were isolated from Hydnocarpus annamensis. The effects of chiral selector type and concentration, buffer composition, pH and concentration, and cartridge temperature on the enantioseparation were investigated. A baseline separation of the four stereoisomers was achieved in less than 18 min under the optimized conditions: 40 mmol L−1 Borax–NaOH buffer (pH 10.02) in the presence of 100 mmol L−1 HP-β-CD at 15°C and 30 kV. The experimental results showed that the method by capillary zone electrophoresis for the separation of four stereoisomers is powerful, sensitive and fast, requires less amounts of reagents, and can be employed as a reliable alternative to other methods. 相似文献