检索结果-南通市图书馆

Rational Solutions of First Order Algebraic Ordinary Differential Equations

在线全文

学校读者我要写书评

暂无评论

Journal of Systems Science & Complexity 2024年第2期37卷 567-580页

作者： feng shuang SHEN Liyong School of Physical and Mathematical Sciences Nanjing Tech UniversityNanjing 211816China School of Mathematical Sciences University of Chinese Academy of SciencesBeijing 100049China

Let f(t,y,y')=∑ _(i=0)^(n )a_(i)(t,y)y'^(i)=0 be an irreducible first order ordinary differential equation with polynomial *** in 1998 proved that there exists a constant C such that every rational solution of f(t,y,y')=0 is of degree not greater than *** show that this degree bound C depends not only on the degrees of f in t,y,y' but also on the coefficients of f viewed as the polynomial in t,y,y'.In this paper,the authors show that if f satisfies deg(f,y)0,then the degree bound C only depends on the degrees of f in t,y,y',and furthermore we present an explicit expression for C in terms of the degrees of f in t,y,y'.

关键词： Degree bound first order AODE height rational solution

Improving Diversity with Multi-Loss Adversarial Training in Personalized News Recommendation

在线全文

学校读者我要写书评

暂无评论

Computers, Materials & Continua 2024年第8期80卷 3107-3122页

作者： Ruijin Xue shuang feng Qi Wang School of Computer and Cyber Sciences Communication University of ChinaBeijing100024China State Key Laboratory of Media Convergence and Communication Communication University of ChinaBeijing100024China

Users’interests are often diverse and multi-grained,with their underlying intents even more *** captur-ing users’interests and uncovering the relationships between diverse interests are key to news ***,diversity is an important metric for evaluating news recommendation algorithms,as users tend to reject excessive homogeneous information in their recommendation ***,recommendation models themselves lack diversity awareness,making it challenging to achieve a good balance between the accuracy and diversity of news *** this paper,we propose a news recommendation algorithm that achieves good performance in both accuracy and *** most existing works that solely optimize accuracy or employ more features to meet diversity,the proposed algorithm leverages the diversity-aware capability of the ***,we introduce an augmented user model to fully capture user intent and the behavioral guidance they might undergo as a ***,we focus on the relationship between the original clicked news and the augmented clicked ***,we propose an effective adversarial training method for diversity(AT4D),which is a pluggable component that can enhance both the accuracy and diversity of news recommendation *** experiments on real-world datasets confirm the efficacy of the proposed algorithm in improving both the accuracy and diversity of news recommendations.

关键词： News recommendation diversity accuracy data augmentation

Manipulations Between Eigenstates of 2-Level Quantum System Based on Optimal Measurements

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

IEEE/CAA Journal of Automatica Sinica 2016年第1期3卷 35-41页

作者： Jingbei Yang shuang Cong feng shuang Herschel Rabitz Department of Automation University of Science and Technology of China IEEE Institute of Intelligent Machines Chinese Academy of Sciences Department of Chemistry Princeton University

This paper explores the manipulation between eigenstates in a two-level system by a sequence of instantaneous projective measurements. Three cases of the manipulations are studied: the manipulation of optimal measurement-based control; the optimal measurement-based manipulation with the effect of free evolution of system; and the external control fields being used to compensate for the effect caused by the free evolution. Numerical simulations are conducted to verify the results obtained from the theoretically analytical solutions. The optimal parameters for each manipulation case are obtained. The experimental results indicate that the external control fields can make the optimal measurement-based control more effective. © 2014 Chinese Association of Automation.

关键词： Quantum optics

Performance analysis of fuzzy BLS using different cluster methods for classification

在线全文

学校读者我要写书评

暂无评论

Science China(Information Sciences) 2021年第4期64卷 232-234页

作者： shuang feng C.L.Philip CHEN School of Applied Mathematics Beijing Normal University Faculty of Science and Technology University of Macau

Dear editor,Neural networks (NNs) and fuzzy systems are commonly used computational intelligence techniques, each with their own merits in terms of applications. The integration of NNs and fuzzy systems, which leads to a hybrid framework known as neuro-fuzzy systems, inherits the useful properties of its constituents:the learning power of an NN and the knowledge representation of a fuzzy inference system,

关键词： fuzzy broad learning system clustering fuzzy c-means classification TSK fuzzy system

Stereoselective Synthesis of Nontethered trans-4 Bis(aziridino)[60]fullerene Derivatives

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Chemistry 2023年第18期41卷 2282-2288页

作者： Jie Xiong shuang feng Rufang Peng Bo Jin State Key Laboratory of Environment-friendly Energy Materials Southwest University of Science and TechnologyMianyangSichuan 621010China

Comprehensive Summary,The stereoselective preparation of fullerene bis-adducts through nontethered methods remains difficult due to the significant amount of regioisomers *** trans-4 aziridino[60]fullerenes,C_(60)(NC_(6)H_(4)R)n(n=1 or 2,R=OMe,OEt,OBu),were selectively synthesized even without a catalyst by reacting octabromofullerene with the corresponding *** magnetic resonance spectroscopy,UV-vis spectroscopy,and X-ray structural analysis provided convincing characterization of the compounds.A possible reaction process was proposed to clarify the synthesis of highly regioselective trans-4-bisaziridino[60]*** possible application of these aziridino[60]fullerene derivatives as propellant stabilizers was also explored.

关键词： Fullerene Regioselectivity Mechanism Nitrocellulose Stability

Optimal quantum measurement of finite-dimensional systems and coherent anti-Stokes Raman spectroscopy

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Science Bulletin 2012年第18期57卷 2215-2222页

作者： GAO Fang WANG YaoXiong shuang feng Institute of Intelligent Machines Chinese Academy of SciencesHefei 230031China State Key Laboratory of Robotics Shenyang Institute of AutomationChinese Academy of SciencesShenyang 110016China

Quantum measurement is a fundamental problem in quantum control theory and *** can obtain unknown information of quantum systems,and can also change state of the systems *** the outcome and back action could be used to control quantum *** paper presents recent research progress about optimal control of state transformation in finite-dimensional quantum systems by back action of non-selective quantum measurement,and optimal control of signal and background of CARS (coherent anti-Stokes Raman spectroscopy) by phase shaping *** measurement sequence control of finite-dimensional quantum systems,the necessary condition for critical points of the underlying state transformation objective is found to be a highly symmetric form as a chain of equalities,and analytical and numerical solutions in several cases are *** the CARS control,it is found that the maximal resonant signal and minimal background at a specific frequency can be achieved by shaping the probe pulse only while keeping pump and Stokes pulses in transform limited forms (TLFs).An arctan-type phase function is obtained for the probe pulse to simultaneously enhance the resonant signal and suppress the *** broadband background elimination,we find that the optimal phase shaping scheme of probe pulse is quasi-time-delay while keeping the pump and Stokes pulses in *** conclusions could help design control strategies of quantum devices.

关键词：量子测量量子系统反斯托克斯拉曼光谱有限维相干控制理论控制状态

Shock wave and bubble characteristics of underwater array explosion of charges

在线全文

学校读者我要写书评

暂无评论

Defence Technology（防务技术） 2022年第8期18卷 1445-1453页

作者： Hong-Wei Hu Pu Song shuang-feng Guo Hai-yun feng Dao-kui Li College of Aerospace Science and Engineering National University of Defense TechnologyChangsha410073HunanChina Xi'an Modern Chemistry Research Institute Xi'an710065ShaanxiChina Hunan Key Laboratory of Intelligent Planning and Simulation for Aerospace Missions Changsha410073HunanChina

In this study, we focused on the effect of the underwater explosion parameters of multi-point array explosion. The shock wave and bubble parameters of aggregate charge, two charges, and four charges were measured through an underwater explosion test, and their influence on the explosion power field of charge quantity and array distance was analyzed. Results show that the multi-shock wave collision of array explosion can be approximated to a linear superposition, and the interaction of delayed shock wave can be deemed as the increase of the shock wave baseline. Shock wave focusing and delayed superposition increase the shock wave peak pressure. Compared with the aggregate charge, the greater the number of array explosion points is, the higher the impulse and the gain of the bubble peak pressure are. At the same array distance, the smaller the charge quantity is, the higher the bubble impulse will be. At the same charge quantity, the smaller the array distance is, the higher the bubble impulse will be. The bubble period decreases gradually with the increase of the charge quantity, but the test orientation has little effect on the bubble period.

关键词： Explosion mechanics Underwater explosion Array explosion Shock waveBubble

A new selective fluorescent probe for lead ions

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2009年第3期20卷 326-329页

作者： Mao Zhong Tian feng feng shuang Ming Meng Yue Hua Yuan School of Chemistry and Chemical Engineering Shanxi Datong University Datong 037009 China

A new fluorescent probe （BPbl） for Pb^2＋ has been synthesized, where diethanolamine （receptor） is linked with 4,4-difluoro-4- bora-3a, 4a-diaza-s-indacene （BODIPY）（fluorophore） via a methylene group （spacer）. The absorption （496 nm） and emission （505 nm） wavelengths are in visible range. The fluorescence quantum yields of the lead-free and lead-bound states of BPb1 in acetonitrile are 0.013 and 0.693, respectively. The large chelation enhanced fluorescence effect （CHEF） with Pb^2＋ can be explained by the blocking of the photoinduced electron transfer （PET） process.

关键词： Pb^2+ Selectivity Photo-induced electron transfer Fluorescence

Coherent Control of Multiple 2nd-Order Quantum Pathways

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemical Physics 2015年第4期28卷 -页

作者： Fang Gao Yao-xiong Wang De-wen Cao feng shuang Institute of Intelligent Machines Chinese Academy of Sciences Hefei 230031 China Institute of Intelligent Machines Chinese Academy of Sciences Hefei 230031 ChinaDepartment of Automation University of Science and Technology of China Hefei 230027 China

The manipulation of two 2nd-order quantum pathways has been successfully demonstrated experimentally in atomic Rubidium. This work would explore the coherent control of pathways in the quantum system with N intermediate states connecting the initial and target states. A 4N-block scheme is proposed to control the N 2nd-order pathways which are driven by a weak broadband pulse. The model with N=3 is given as an example to demonstrate our strategy. In this scheme, boundaries of the spectral blocks are functions of the resonant frequencies, and the resonant and non-resonant contributions interfere mutually to achieve the quantum pathway control effectively. The simple strategy may provide a practical choice for pathway manipulation experiments since there are only 2N phase variables to adjust.

关键词： Coherent control Multiple 2nd-order Quantum pathway