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On the Possibility to Construct Gravitational Eye

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Communications in Theoretical Physics 2007年第5期47卷 851-860页

作者： chen Ying-tian Department of Astronomy and Applied Physics University of Science and Technology of China Hefei 230026 China Institute of Theoretical Physics the Chinese Academy of Sciences Beijing 100080 China Cavendish Laboratory University of Cambridge Cambridge U.K.

The possibility of modifying a conventional Cavendish torsion pendulum into a half-armed pendulum oscillator to measure the horizontal gravitational acceleration is discussed. A new kind of gravitational detector, gravieye, as we named, can be made by a proper combination of such oscillators to ＂see＂ remote objects and to be used, e.g. to detect the movement of huge mass at a long distance.

关键词： gravitational eye Cavandish torsion pendulum gravitational experiment gravieye

Fast quantum search driven by environmental engineering

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Communications in Theoretical Physics 2022年第4期74卷 31-41页

作者： Rui Zhang tian chen National Engineering Laboratory for Risk Perception and Prevention(NEL-RPP) CAEITBeijing 100041China Beijing Key Laboratory of Nanophotonics and Ultrafine Optoelectronic Systems School of PhysicsBeijing Institute of TechnologyBeijing 100081China

Studies have demonstrated that a joined complete graph is a typical mathematical model that can support a fast quantum search. In this paper, we study the implementation of joined complete graphs in atomic systems and realize a quantum search of runtime ■ based on this implementation with a success probability of 50%. Even though the practical systems inevitably interact with the surrounding environment, we reveal that a successful quantum search can be realized through delicately engineering the environment itself. We consider that our study will bring about a feasible way to realize quantum information processing including quantum algorithms in reality.

关键词： quantum walk quantum search algorithm environmental engineering non-Markovian

Continuous-Time Mean-Variance Portfolio Selection Under Non-Markovian Regime-Switching Model with Random Horizon

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Journal of Systems Science & Complexity 2023年第2期36卷 457-479页

作者： chen tian LIU Ruyi WU Zhen Zhongtai Securities Institute for Financial Studies Shandong UniversityJinan 250100China School of Mathematics and Statistics University of SydneyNSW 2006Australia School of Mathematics Shandong UniversityJinan 250100China

This paper considers a continuous-time mean-variance portfolio selection with regime-switching and random *** previous works,the dynamic of assets are described by non-Markovian regime-switching models in the sense that all the market parameters are predictable with respect to the filtration generated jointly by Markov chain and Brownian *** Markov chain is assumed to be independent of Brownian motion,thus the market is *** authors formulate this problem as a constrained stochastic linear-quadratic optimal control *** authors derive closed-form expressions for both the optimal portfolios and the efficient *** the results are different from those in the problem with fixed time horizon.

关键词： Backward stochastic differential equation mean-variance portfolio selection random time horizon stochastic LQ control

GAG-containing nucleotides as mediators of DNA-silver clusters and iron-DNA interplay

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Chinese Chemical Letters 2016年第3期27卷 395-398页

作者： tian-tian chen Qiu-Yun chen Ming-Yang Liu School of Chemistry and Chemical Engineering Jiangsu University State Key Laboratory of Coordination Chemistry Nanjing University

New types of fluorescence DNA-based silver nanoclusters（DNAn-Ag NCs, n = 1, 2, 3c, 4c, 5c） were synthesized by C3T-rich nucleotides as templates. It is found that the assembly of DNAn-Ag NCs with nucleotides containing GAG sequences produce silver clusters with an enhanced red emission. Results indicate that GAG is the good enhancer of DNAn-Ag NCs constructed by C3T-rich nucleotides. The fluorescence titration reveals that enhanced red emission is sensitive to Fe（Ⅲ/Ⅱ） ions with the formation of non-emission nanoclusters. Thus, the GAG-containing nucleotide can be an enhancer for the emission of silver clusters with C3T-rich nucleotide and a mediator of the iron-cluster interplay.

关键词： DNA Silver cluster Fluorescence Iron

Nonlinear vibration analysis of a circular composite plate harvester via harmonic balance

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Acta Mechanica Sinica 2019年第4期35卷 912-925页

作者： tian-chen Yuan Jian Yang Li-Qun chen Shanghai Institute of Applied Mathematics and Mechanics Shanghai University Shanghai 200072 China School of Urban Railway Transportation Shanghai University of Engineering Science Shanghai 201620 China Department of Mechanics Shanghai University Shanghai 200444 China Shanghai Key Laboratory of Mechanics in Energy Engineering Shanghai University Shanghai 200072 China

Alumped parameter transversevibration model of a composite plate harvester is analyzed via harmonic balance approaches. The harvester is mainly composed of a piezoelectriccircular composite clamped by two steel rings and a proof mass on the *** lumped parameter model is a 1.5 degree-of-freedom strongly nonlinear system with a higher order polynomial stiffness. Aharmonic balance approach is developed to analyze the system, and the resulting algebraic equations are numerically solved by adopting an arc-length continuation technique. Anincremental harmonic balance approach is also developedfor the lumped parameter model. The two approaches yieldthe same *** amplitude-frequency responses produced by the harmonic balance approach are validated by the numericalintegrations and the experimental data. The investigation reveals that there coexist hardening and softening characteristics in the amplitude-frequency response curves under sufficiently large excitations. The harvester with thecoexistenceof hardening and softening nonlinearitiescan outperform not only linear energy harvesters but also typical hardening nonlinear energy harvesters.

关键词： Piezoelectricenergy harvester Circular composite plate Transverse nonlinear vibration Harmonic balance Arc-length continuation

Spheres of Urban Influence and Factors in Beijing-tianjin-Hebei Metropolitan Region Based on Viewpoint of Administrative Division Adjustment

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Chinese Geographical Science 2017年第5期27卷 709-721页

作者： ZHU Jianhua chen Xi chen tian School of Geographic Sciences Northeast Normal UniversityChangchun 130024China Institute of Geographic Sciences and Natural Resources Research Chinese Academy of SciencesBeijing 100101China University of Chinese Academy of Sciences Beijing 100049China Northeast Asian Studies College Jilin UniversityChangchun 130012China

The coordinated development of Beijing, tianjin and Hebei has been elevated as China's important strategy. And, the priority in considering how to bring the maximum effect of their coordinated development into play is to delineate the spheres of urban influence with regard to the cities in the Beijing-tianjin-Hebei Metropolitan Region. By building an evaluation index system of urban comprehensive strength, this paper applies the principal component analysis method to determine centrality strength of the cities, and the breakpoint theory and weighted Voronoi diagram to identify the spheres of urban influence in all central cities of the region. Results show that 13 central cities within the region greatly differ in strength, which can be classified into four tiers and that the spheres of urban influence do not have a high goodness of fit with administrative jurisdiction scope. Cities like Beijing, tianjin, Shijiazhuang and Handan have larger spheres of urban, spheres of urban influence in Tangshan and Qinhuangdao are basically consistent with their administrative jurisdiction scopes, and seven cities including Langfang and Baoding have smaller spheres of urban influence. So according to these cities' comprehensive strength and spheres of influence, the region can be divided into five plates: Beijing, tianjin, Shijiazhuang, Tangshan and Handan. The major influence factors for inconsistency between spheres of urban influence and spheres of jurisdiction include difference in urban administrative ranking, small number of central cities with weak strength, discrepancy in the number of counties under jurisdiction, unreasonable spheres of jurisdiction and diversity in topographical conditions. In order to solve the imbalance in the spheres of urban influence and those of jurisdiction and better facilitate the coordinated development of the region, it is advised to adjust administrative areas so as to obtain more optimized urban spatial layout and more reasonable urban scale

关键词： spheres of urban influence urban comprehensive strength adjustment of administrative divisions weighted Voronoi diagram Beijing-tianjin-Hebei Metropolitan Region

Linear-quadratic optimal control for partially observed forward-backward stochastic systems with random jumps

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Science China(Information Sciences) 2022年第11期65卷 217-231页

作者： tian chen Guangchen WANG Zhen WU Zhongtai Securities Institute for Financial Studies Shandong University School of Control Science and Engineering Shandong University School of Mathematics Shandong University

In this paper, we investigate a linear-quadratic(LQ) optimal control problem for partially observed forward-backward stochastic systems with random jumps, where the observation’s drift term is linear with respect to the state x and control variable v. In our model, the observation process is no longer a Brownian motion but a controlled stochastic process driven by Brownian motions and Poisson random measures,which also have correlated noises with the state equation. Applying a backward separation approach to decompose the state and observation, we overcome the problem of cyclic dependence of control and ***, the necessary and sufficient conditions for optimal control are derived. We also obtain the feedback representation of optimal control and provide two special cases to illustrate the significance of our ***, we also provide a financial application to demonstrate the practical significance of our results.

关键词： LQ optimal control partially observed stochastic system random jumps backward separation principle optimal filtering

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A Cryptographic Scheme Based on Spatiotemporal Chaos of Coupled Map Lattices

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Communications in Theoretical Physics 2006年第3期45卷 477-482页

作者： MA Hui chen tian-Lun Institute of Physics Nankai University Tianjin 300071 China CCAST （World Laboratory） P.O. Box 8730 Beijing 100080 China

We propose a cryptographic scheme based on spatiotemporal chaos of coupled map lattices （CIVIL） ,which is based on one-time pad. The structure of the cryptosystem determines that the progress in decryption implies the progress in exploring the dynamical behavior of spatiotemporal chaos in CML. A part of the initial condition of CML is used as a secret key, and the recovery of the secret key by exhaustive search is impossible due to the sensitivity to the initial condition in spatiotemporal chaos system. Specially the software implementation of the scheme is easy.

关键词： spatiotemporal chaos coupled map lattices cryptography

Does a General Temperature-Dependent Q10 Model of Soil Respiration Exist at Biome and Global Scale？

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Journal of Integrative Plant Biology 2005年第11期47卷 1288-1302页

作者： Hua chen Han-Qin tian School of Forestry and Wildlife Sciences Auburn University Auburn AL 36849 USA

Soil respiration （SR） is commonly modeled by a Q10 （an indicator of temperature sensitivity） function in ecosystem models. Q10 is usually treated as a constant of 2 in these models, although Q10 value of SR often decreases with increasing temperatures. It remains unclear whether a general temperature- dependent Q10 model of SR exists at biome and global scale. In this paper, we have compiled the long-term Q10 data of 38 SR studies ranging from the Boreal, Temperate, to Tropical/Sublropical biome on four continents. Our analysis indicated that the general temperature-dependent biome Q10 models of SR existed, especially in the Boreal and Temperate biomes. A single-exponential model was better than a simple linear model in fitting the average Q10 values at the biome scale. Average soil temperature is a better predictor of Q10 value than average air temperature in these models, especially in the Boreal biome. Soil temperature alone could explain about 50% of the Q10 variations in both the Boreal and Temperate biome single-exponential Q10 model. Q10 value of SR decreased with increasing soil temperature but at quite different rates among the three biome Q10 models. The k values （Q10 decay rate constants） were 0.09, 0.07, and 0.02/℃ in the Boreal, Temperate, and Tropical/Subtropical biome, respectively, suggesting that Q10 value is the most sensitive to soil temperature change in the Boreal biome, the second in the Temperate biome, and the least sensitive in the Tropical/ Subtropical biome. This also indirectly confirms that acclimation of SR in many soil warming experiments probably occurs. The k value in the ＂global＂ single-exponential Q10 model which combined both the Boreal and Temperate biome data set was 0.08/℃. However, the global general temperature-dependent Q10 model developed using the data sets of the three biomes is not adequate for predicting Q10 values of SR globally. The existence of the general temperature-dependent Q10 models of SR in the Boreal and Temp

关键词： air temperature biome Q10 model global Q10 model simple linear model single-exponentialmodel soil respiration (SR) soil temperature temperature sensitivity (Q10).