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EXPLAINING THE CHANGES IN ALPS BY IDENTIFYING ALPS-IMPORTANT COEFFICIENTS:AN EMPIRICAL APPLICATION OF CHINA

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Journal of Systems Science & Complexity 2013年第3期26卷 383-406页

作者： LU Xiaolin xu Jian Management School University of Chinese Academy of Sciences

This paper establishes the relation between APLs and direct input coefficients through Sherman-Morrison *** such a basis,elasticity matrix can be calculated for each element of the APLs matrix,which measures the percentage change in the APLs-matrix element brought by one percentage change in every direct input ***,the percentage change in each APLs-matrix element caused by the real percentage change in each coefficient with other coefficients fixed can be drawn,from which it is easily to find out the APLs-important coefficients and is useful to explain the reason for change in the *** empirical application studies the Chinese ***'s more,the method is applied under different level of *** comparison between the APLs matrix of 1997 and 2002 allows the authors to visualize the elements that change *** the methodology above is applied to explain the change from the perspective of direct input coefficients and find out the important coefficients to the Chinese APLs matrix.

关键词： APLs-important coefficients APLs matrix direct input coefficients elasticity matrix Sherman-Morrison formulation.

Analysis of Fluid Model Modulated by an M/PH/1 Working Vacation Queue

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Journal of Systems Science and Systems Engineering 2019年第2期28卷 132-140页

作者： Xiuli xu Huining Wang School of Science Yanshan University Qinhuangdao 066004 China

We propose a fluid model driven by the queue length process of a working vacation queue with PH service distribution, which can be applied to the Ad Hoc network with every data group. We obtain the stationary distribution of the queue length in driving process based on a quasi-birth-and-death process. Then, we analyze the fluid model, and derive the differential equations satisfied by the stationary joint distribution of the fluid queue based on the balance equation. Moreover, we obtain some performance indices, such as, the average throughput, server utilization and the mean buffer content. These indices are relevant to pack transmission in the network, and they can be obtained by using the Laplace Transform (LT) and the Laplace-Stieltjes Transform (LST). Finally, some numerical examples have been discussed with respect to the effect of several parameters on the system performance indices.

关键词： Fluid model M/PH/1 queue average throughput server utilization buffer content Ad Hoc network

Rare nanoparticles shine colors with low-power STED

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Light(Science & Applications) 2022年第7期11卷 1324-1326页

作者： xinzhu xu Peng Xi College of Future Technology Peking UniversityBeijingChina

The effect of cascade amplified depletion in lanthanide upconversion systems boosts their own emission bands inhibition,which facilitates multi-color nanoscopy with only one pair of low-power NIR CW lasers.

关键词： Rare lanthanide bands

A NEW HYBRID ELEMENT ANALYSIS FOR EXPONENTIALLY VARYING FGM BASED ON AN ASYMPTOTIC STRESS FIELD

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Acta Mechanica Solida Sinica 2014年第3期27卷 315-330页

作者： Chen Wang Xiwu xu State Key Laboratory of Mechanics and Control of Mechanical Structures Nanjing University of Aeronautics and Astronautics

A hybrid finite element for exponentially varying Fhnctionally Graded Material （FGM） is established based on a derived stress field for an intact plate. Elements with both single layer and two layers of gradient are presented. The general stress field is obtained through an asymptotic analysis coupled with Westergaard＇s stress function approach. With the aid of boundary collocation technique, convergence of the derived stress field is verified. Effectiveness and efficiency of the element is investigated through calculation and comparison. Based on that element, stress field of FGM plate under different loading cases is studied briefly.

关键词： finite element method hybrid method complex function functionally graded materials

Effects of urea and(NH_4)_2 SO_4 on nitrification and acidification of Ultisols from Southern China

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Journal of Environmental Sciences 2012年第4期24卷 682-689页

作者： Dell Tong renkou xu State Key Laboratory of Soil and Sustainable Agriculture Institute of Soil ScienceChinese Academy of SciencesNanjing 210008China Graduate University of Chinese Academy of Sciences Beijing 100049China

The mechanisms for the effects of ammonium-based fertilizers on soil acidification in subtropical regions are not well understood. Two Ultisols collected from cropland and a tea garden in Anhui and Jiangxi Provinces in subtropical southern China, respectively, were used to study the effects of urea and （NH4）aSO4 on the nitrification and acidification of soils with incubation experiments. Nitrification occurred at very low pH with no N fertilizer added and led to lowering of the soil pH by 0.53 and 0.30 units for the soils from Jiangxi and Anhui, respectively. Addition of urea accelerated nitrification and soil acidification in both Ultisols; while nitrification was inhibited by the addition of （NH4）2SO4, and greater input of （NH4）2SO4 led to greater inhibition of nitrification. Ammonia-oxidizing bacteria （AOB） played an important role in nitrification in cropland soil under acidic conditions. Addition of urea increased the soil pH at the early stages of incubation due to hydrolysis and stimulated the increase in the AOB population, and thus accelerated nitrification and soil acidification. At the end of incubation, the pH of Ultisol from Jiangxi had decreased by 1.25, 1.54 and 1.84 units compared to maximum values for the treatments with 150, 300 and 400 mg/kg of urea-N added, respectively; the corresponding figures were 0.95, 1.25 and 1.69 for the Ultisol from Anhui. However, addition of （NH4）：SO4 inhibited the increase in the AOB population and thus inhibited nitrification and soil acidification. Soil pH for the treatments with 300 and 400 mg/kg of （NHn）2SOa-N remained almost constant during the incubation. AOB played an important role in nitrification of the cropland soil under acidic conditions. Addition of urea stimulated the increase in the AOB population and thus accelerated nitrification and soil acidification; while addition of （NH4）2SO4 inhibited the increase in the AOB population and thus inhibited nitrification.

关键词： ammonium-based fertilizer nitrification soil acidification ammonia-oxidizing prokaryotes

Challenges and prospects for room temperature solid-state sodiumsulfur batteries

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Nano Research 2024年第3期17卷 1402-1426页

作者： Yashuang Qiu Jing xu Research Center of Grid Energy Storage and Battery Application School of Electrical and Information EngineeringZhengzhou UniversityZhengzhou 450001China

Room temperature sodium-sulfur(Na-S)batteries,known for their high energy density and low cost,are one of the most promising next-generation energy storage ***,the polysulfide shuttling and uncontrollable Na dendrite growth as well as safety issues caused by the use of organic liquid electrolytes in Na-S cells,have severely hindered their ***-state electrolytes instead of liquid electrolytes are considered to be the most direct and effective solution to solve the above ***,its practical application is still greatly challenged due to the poor interfacial compatibility between the all-solid-state electrolytes and the anode/cathode,ionic conductivity,and the shuttle effect caused by the presence of liquid phase in the quasi-solid-state *** paper presents a comprehensive review of solid-state Na-S batteries from the perspective of regulating interfacial compatibility and improving ionic conductivity as well as suppressing polysulfide *** to different components,solid-state electrolytes were divided into five categories:solid inorganic electrolytes,solid polymer electrolytes,polymer/inorganic solid hybrid electrolytes,gel polymer electrolytes,and liquid–solid inorganic hybrid ***,the prospect of developing high performance solid-state electrolytes to improve the cycling stability of room temperature Na-S cells is envisaged.

关键词： sodium-sulfur batteries solid-state electrolytes ionic conductivity polysulfide shuttling interfacial compatibility

On Feasible Region of Droop-based Fast Frequency Response Controller Parameters of Wind Turbines

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Journal of Modern Power Systems and Clean Energy 2024年第5期12卷 1690-1695页

作者： Junkai Huang Yan xu School of Electrical and Electronic Engineering Nanyang Technological University50 Nanyang AvenueSingapore

Droop-based fast frequency response(FFR)control of wind turbines can improve the frequency performance of power systems with high penetration of wind *** formulating the feasible region of the droop-based FFR controller parameters can allow system operators to conveniently assess the feasibility of FFR controller parameter settings to comply with system frequency security,and efficiently tune and optimize FFR controller parameters to meet frequency security ***,the feasible region of FFR controller parameters is inherently nonlinear and implicit because the power point tracking controllers of wind turbine would counteract the effect of FFR *** address this issue,this letter proposes a linear feasible region formulation method,where frequency regulation characteristics of wind turbines,the dead band,and reserve limits of generators are all *** effectiveness of the proposed method and its application is demonstrated on a 10-machine power system.

关键词： Wind turbine fast frequency response feasible region frequency security

A novel weighting scheme for random k-SAT

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Science China(Information Sciences) 2016年第9期59卷 5-10页

作者： Jun LIU Ke xu State Key Laboratory of Software Development Environment Beihang University

Consider a random k-conjunctive normal form F;（n, rn） with n variables and rn clauses. We prove that if the probability that the formula Fk（n, rn） is satisfiable tends to 0 as n →∞, then r≥2.83, 8.09, 18.91,40.... 详细信息

关键词： computational complexity satisfiability phase transition second moment method weighting scheme

Lighting up rotaxanes with AIEgens

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Chinese Chemical Letters 2023年第3期34卷 122-133页

作者： Xiao-Qin xu xu-Qing Wang Wei Wang School of Chemistry and Molecular Engineering East China Normal UniversityShanghai 200062China Guangdong Provincial Key Laboratory of Functional and Intelligent Hybrid Materials and Devices South China University of TechnologyGuangzhou 510640China

Aiming at the construction of novel rotaxanes with desired luminescent properties for practical applications, recently the rapid development of rotaxanes decorated with aggregation-induced emission(AIE) luminogens(i.e., AIEgens) has been witnessed. The combination of AIEgens and rotaxanes leads to the successful construction of a novel type of luminescent rotaxanes with many attractive features. In particular, the unique controllable dynamic feature of rotaxanes endows the resultant AIEgen-based rotaxanes precisely tunable emissions under external stimuli, leading to the construction of a novel type of smart luminescent materials. In this minireview, the recent progress of AIEgen-based rotaxanes has been summarized, with an emphasis on the design strategy and potential applications.

关键词： Mechanically interlocked molecules Aggregation-induced emission Molecular shuttles F?rster resonance energy transfer Light harvesting Aggregate