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Correspondence between quantum-optical transform and classical-optical transform explored by developing Dirac＇s symbolic method

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Frontiers of physics 2012年第3期7卷 261-310页

作者： Hong-yi Fan li-yun hu Department of Physics Shanghai Jiao Tong UniversityShanghai 200030China College of Physics&Communication Electronics Jiangxi Normal UniversityNanchang 330022China Department of Material Science and Engineering University of Science and Technology of China Hefei 230026 China

By virtue of the new technique of performing integration over Dirac＇s ket-bra operators, we ex- plore quantum optical version of classical optical transformations such as optical Fresnel transform, Hankel transform, fractional Fourier transform, Wigner transform, wavelet transform and Fresnel- Hadmard combinatorial transform etc. In this way one may gain benefit for developing classical optics theory from the research in quantum optics, or vice-versa. We cannot only find some new quantum mechanical unitary operators which correspond to the known optical transformations, de- riving a new theorem for calculating quantum tomogram of density operators, but also can reveal some new classical optical transformations. For examples, we find the generalized Fresnel opera- tor （GFO） to correspond to the generalized Fresnel transform （GFT） in classical optics. We derive GFO＇s normal product form and its canonical coherent state representation and find that GFO is the loyal representation of symplectic group multiplication rule. We show that GFT is just the transformation matrix element of GFO in the coordinate representation such that two successive GFTs is still a GFT. The ABCD rule of the Gaussian beam propagation is directly demonstrated in the context of quantum optics. Especially, the introduction of quantum mechanical entangled state representations opens up a new area in finding new classical optical transformations. The complex wavelet transform and the condition of mother wavelet are studied in the context of quantum op- tics too. Throughout our discussions, the coherent state, the entangled state representation of the two-mode squeezing operators and the technique of integration within an ordered product （IWOP） of operators are fully used. All these have confirmed Dirac＇s assertion：＂...for a quantum dynamic system that has a classical analogue, unitary transformation in the quantum theory is the analogue of contact transformation in the classical theory＂.

关键词： Dirac's symbolic method IWOP technique entangled state of continuum variables entangled Fresnel transform Collins formula Generalized Fresnel operator complex wavelet trans-form complex Wigner transform complex fractional Fourier transform symplectic wavelet trans-form entangled symplectic wavelet transform Symplectic-dilation mixed wavelet transform frac-tional Radon transform new eigenmodes of fractional Fourier transform

Efficient multi-event monitoring using built-in search engines

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维普期刊数据库

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Frontiers of Computer Science 2016年第2期10卷 281-291页

作者： Zhaoman ZHONG Zongtian liU yun hu Cunhua li School of Computer Engineering Huaihai Institute of Technology Lianyungang 222006 China School of Computer Engineering and Science Shanghai University Shanghai 200072 China

Users of the internet often wish to follow certain news events, and the interests of these users often overlap. General search engines （GSEs） cannot be used to achieve this task due to incomplete coverage and lack of freshness. Instead, a broker is used to regularly query the built-in search engines （BSEs） of news and social media sites. Each user defines an event profile consisting of a set of query rules called event rules （ERs）. To ensure that queries match the semantics of BSEs, ERs are transformed into a disjunctive normal form, and separated into conjunctive clauses （atomic event rules, AERs）. It is slow to process all AERs on BSEs, and can violate query submission rate limits. Accordingly, the set of AERs is reduced to eliminate AERs that are duplicates, or logically contained by other AERs. Five types of event are selected for experimental comparison and analysis, including natural disasters, accident disasters, public health events, social security events, and negative events of public servants. Using 12 BSEs, 85 ERs for five types of events are defined by five users. Experimental comparison is conducted on three aspects： event rule reduction ratio, number of collected events, and that of related events. Experimental results in this paper show that event rule reduction effectively enhances the efficiency of crawling.

关键词： information retrieval event retrieval event monitoring BSEs event rule reduction

Comparative Study on Optical Properties and Scratch Resistance of Nanocomposite Coatings Incorporated with Flame Spray Pyrolyzed Silica Modified via in-situ Route and ex-situ Route

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Journal of Materials Science & Technology 2016年第3期32卷 251-258页

作者： yun Wang ling Zhang Yanjie hu Chunzhong li Key Laboratory for Ultrafine Materials of Ministry of Education School of Materials Science and Engineering East China University of Science and Technology

A new type of transparent scratch resistant coatings including in-situ modified SiO2 （g-SiO2） in flame spray pyrolysis （FSP） process was prepared. The maximum content of g-SiO2 in the coating was 15 wt%, which is higher than that of SiO2 modified by traditional wet chemical route （I-SiO2, only 10 wt%）. The results of transmission electron microscopy have demonstrated that in-situ surface modified g-SiO2 particles dispersed well with smaller agglomerates in the final coating, which was much better than the particles modified via wet chemical route. Visible light transmittance and haze tests were introduced to characterize the optical quality of the films. All coatings were highly transparent with the visible light transmittance of above 80%, especially for coatings containing g-SiO2, which exhibited slightly higher visible light transmittance than l-SiO2 embedded one. The haze value of coatings incorporated with 15 wt% g-SiO2 was 1.85%, even lower than the coating with 5 wt% I-SiO2 （haze value of 2.09%）, indicating much better clarity of g-SiO2. The excellent optical property of g-SiO2 filled coatings was attributed to the good dispersion and distribution of particles. Nano-indention and nano-scratch tests were con- ducted to investigate the scratch resistance of coatings on nano-scale. The surface hardness of the coatings rose by 18% and 14%, and the average friction coefficient decreased by 15% and 11%, respectively, compared to the neat coat due to the addition of 10 wt% g-SiO2 and I-SiO2. The pencil hardness of the coating with 15 wt% g-SiO2 increased from 2B for the neat coating to 2H. However, the pencil hardness of coating with 10 wt% I-SiO2 was only H. The results showed that the g-SiO2 embedded coatings exhibited higher scratch resistance and better optical properties.

关键词： ln-situ modification Silica Coating Scratch resistance Optical property

Event-triggered adaptive control for attitude tracking of spacecraft

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Chinese Journal of Aeronautics 2019年第2期32卷 454-462页

作者： Chenliang WANG yun li Qinglei hu Jian huANG School of Automation Science and Electrical Engineering Beihang University Beijing Institute of Automatic Control Equipment

Plug-and-play technology is an important direction for future development of spacecraft and how to design controllers with less communication burden and satisfactory performance is of great importance for plug-and-play spacecraft. Considering attitude tracking of such spacecraft with unknown inertial parameters and unknown disturbances, an event-triggered adaptive backstepping controller is designed in this paper. Particularly, a switching threshold strategy is employed to design the event-triggering mechanism. By introducing a new linear time-varying model, a smooth function, an integrable auxiliary signal and a bound estimation approach, the impacts of the network-induced error and the disturbances are effectively compensated for and Zeno phenomenon is successfully avoided. It is shown that all signals of the closed-loop system are globally uniformly bounded and both the attitude tracking error and the angular velocity tracking error converge to zero. Compared with conventional control schemes, the proposed scheme significantly reduces the communication burden while providing stable and accurate response for attitude maneuvers. Simulation results are presented to illustrate the effectiveness of the proposed scheme.

关键词： Adaptive control Attitude tracking Event-triggered control Spacecraft Uncertainties

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去乙酰化酶SIRT2及其抑制剂的研究进展

中国药物化学杂志 2017年第4期27卷 315-324页

作者：彭亚军胡高云李乾斌中南大学湘雅药学院湖南长沙410013

Sirtuin2(SIRT2)是一种烟酰胺腺嘌呤二核苷酸(NAD^+)依赖性的组蛋白去乙酰化酶,是沉默信息调节因子2(Sir2)相关蛋白家族的重要成员。SIRT2通过催化不同的底物去乙酰化参与了许多生物学过程,比如基因沉默、细胞周期调控、细胞代谢、细胞... 详细信息

Sirtuin2(SIRT2)是一种烟酰胺腺嘌呤二核苷酸(NAD^+)依赖性的组蛋白去乙酰化酶,是沉默信息调节因子2(Sir2)相关蛋白家族的重要成员。SIRT2通过催化不同的底物去乙酰化参与了许多生物学过程,比如基因沉默、细胞周期调控、细胞代谢、细胞凋亡等。研究表明,在许多神经退行性疾病模型中,抑制SIRT2能够对神经元细胞产生明显的保护作用。因此,SIRT2有望成为治疗神经退行性疾病的重要靶点。本文主要对SIRT2的结构、功能、SIRT2与神经退行性疾病的关系、SIRT2抑制剂及其构效关系做一综述,旨在为以SIRT2为靶点的神经退行性疾病药物研发提供参考。

关键词：组蛋白去乙酰化酶 SIRT2 神经退行性疾病抑制剂

In situ Surface Functionalization of Hydrophilic Silica Nanoparticles via Flame Spray Process

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Journal of Materials Science & Technology 2015年第9期31卷 901-906页

Hydrophobic silica nanoparticles grafted with a high amount of organic molecules were successfully pre- pared by an in situ functionalization method in flame spray pyrolysis （FSP） process. Hydrophilic SiO2 nanoparticles were converted into hydrophobic ones by silylation between 3-methacryloxypropyltrimethoxyl silane （MPS） and silica＇s surface hydroxyl groups. The freshly formed silica nanoparticles in flame were continuously functionalized by a fine spray of 3-methacryloxypropyltrimethoxyl silane （MPS） solution at a preferred temperature. The functionalization extent, morphology structure and size of silica nanoparticles were characterized by transmission electron microscopy （TEM）, Brunauer-Emmett- Teller （BET）, thermogravimetric analysis （TGA）, Fourier transform infrared spectroscopy （FT-IR） and X-ray photoelectronic spectroscopy （XPS）. The influence of concentration, pH value and pre-activation of organic silane solution on the surface grafting density was investigated in detail. The obtained silica nanoparticles had a higher MPS functional content of 15.0 wt% （an average density of 2.7 MPS molecule/nm^2） than that of the silica modified by wet chemistry route, showing an excellent, stable hydrophobic property. The results have demonstrated that the in situ FSP functionalization process is a simple, effective and prom- ising route for the scalable preparation of advanced, hydrophobic nanomaterials.

关键词： SilicaIn situ functionalizationHydrophobicFlameModification

Annual and interannual variations of sea-level anomaly in the Bay of Bengal and the Andaman Sea

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Acta Oceanologica Sinica 2007年第6期26卷 13-29页

作者： QIU yun li li YU Weidong hu Jianyu State key laboratory of Marine Environmental Science College of Oceanography and Environmental Science Xiamen University Xiamen 361005 China Third Institute of Oceanography State Oceanic Administration Xiamen 361005 China First Institute of Oceanography State Oceanic Administration Qinddao 266061 China

Annual and interannual variations of sea-level anomaly （SLA） in the Bay of Bengal and the Andaman Sea are investigated using altimeter - derived SLA data from 1993 to 2003. It is found that the SLA annual variation in the study area can be divided into three phases with distinctive patterns. During the southwest monsoon （May -September）, positive SLA presents in the equatorial region and extends northward along the eastern boundary of the bay, and the SLA distribution in the interior bay appears to be high in the east and low in the west with two cyclonic ceils developing in the north and south of the western bay respectively, between which an anticyclonic cell exists. During the early northeast monsoon （ October - December） , the whole bay is dominated by a large cyclonic cell with the pattern of high SLA in the east and low in the west still retained, and the SLA distribution outside the bay is changed in response to the reversal of the Indian Monsoon Current （IMC） in November. During the late northeast monsoon （January -April） , a large anticyclonic cell of SLA develops in the bay with negative SLA prevailing in the equatorial region and extending northward along the eastern boundary of bay. Therefore, the SLA distribution in the interior bay reverses to be high in the west and low in the east. It is suggested that the SLA annual variation in the bay is primarily driven by the local wind stress curl, involving Sverdrup balance while the abrupt SLA variation during the peak of northeast monsoon may be partly caused by the semiannual fluctuation of wind in the equatorial region. This fast adjustment in the interior bay is induced by the upwelling coastal Kelvin wave excited by the decay of Wyrtki jet during December through January. Besides the annual variation, in the bay, there are obvious SLA fluctuations with the periods of 2 and 3 - 7 a, which are driven by the interannual variability of large - scale wind field in the equatorial region. The coastal Kelvin wav

关键词： Bay of Bengal sea-level anomaly low-frequency variation satellite altimeter

Extracting compressive stress-strain curve based on stick-slip shear banding process in bulk metallic glasses

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Journal of Iron and Steel Research International 2017年第4期24卷 372-377页

作者： Jing hu yun-xuan Weng Xiao-li li Bao-an Sun School of Material and Mechanical Engineering Beijing Technology and Business University Herbert Gleiter Institute of Nanoscience Nanjing University of Science & Technology

Based on the stick-slip process,an effective method to extract the stress-strain curve directly from the crosshead displacement-load raw data in compression of bulk metallic glasses was *** method was tested in two bulk metallic glass samples with different plasticities and shear band *** extracted stress-strain curves were found to well resemble the stress-strain curve measured by a laser *** addition,the extracted curve could resolve fine structures of serrated flow much better than that measured by extensometer,thus facilitating the study of shear banding *** obtained by this method made the stick-slip dynamics of shear banding valid,and this method could be employed to obtain the real strain of small-sized metallic glass samples where extensometer cannot be applied.

关键词： Serrated flow Shear banding Stick-slip Stress-strain curve

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无线传感网络关键技术及在环境监测中的应用

自动化技术与应用 2021年第12期40卷 116-120页

作者：王普红乔治宏胡运立李志军防化研究院北京昌平102205

回顾了无线传感网络技术的发展历史,对无线传感网络的结构和关键技术进行详细阐述;综述了无线传感网络技术在环境监测中的研究及应用现状,对该技术的发展方向和趋势作一展望。

关键词：无线传感器环境监测