期刊文献+
共找到37篇文章
< 1 2 >
每页显示 20 50 100
Entanglement dynamics of a moving multi-photon Jaynes-Cummings model in mixed states 被引量:2
1
作者 谭磊 张玉青 朱中华 《Chinese Physics B》 SCIE EI CAS CSCD 2011年第7期57-63,共7页
Using the algebraic dynamical method, the entanglement dynamics of an atom-field bipartite system in a mixed state is investigated. The atomic center-of-mass motion and the field-mode structure are also included in th... Using the algebraic dynamical method, the entanglement dynamics of an atom-field bipartite system in a mixed state is investigated. The atomic center-of-mass motion and the field-mode structure are also included in this system. We find that the values of the detuning and the average photon number are larger, the amplitude of the entanglement is smaller, but its period does not increase accordingly. Moreover, with the increase of the field-mode structure parameter and the transition photon number, the amplitude of the entanglement varies slightly while the oscillation becomes more and more fast. Interestingly, a damping evolution of the entanglement appears when both the detuning and the atomic motion are considered simultaneously. 展开更多
关键词 algebraic dynamical method ENTANGLEMENT mixed state
下载PDF
CONTINUOUS TIME MIXED STATE BRANCHING PROCESSES AND STOCHASTIC EQUATIONS 被引量:1
2
作者 陈舒凯 李增沪 《Acta Mathematica Scientia》 SCIE CSCD 2021年第5期1445-1473,共29页
A continuous time and mixed state branching process is constructed by a scaling limit theorem of two-type Galton-Watson processes.The process can also be obtained by the pathwise unique solution to a stochastic equati... A continuous time and mixed state branching process is constructed by a scaling limit theorem of two-type Galton-Watson processes.The process can also be obtained by the pathwise unique solution to a stochastic equation system.From the stochastic equation system we derive the distribution of local jumps and give the exponential ergodicity in Wasserstein-type distances of the transition semigroup.Meanwhile,we study immigration structures associated with the process and prove the existence of the stationary distribution of the process with immigration. 展开更多
关键词 mixed state branching process weak convergence stochastic equation system Wasserstein-type distance stationary distribution
下载PDF
Experimentally testing Hardy's theorem on nonlocality with entangled mixed states 被引量:1
3
作者 樊代和 戴茂春 +1 位作者 郭伟杰 韦联福 《Chinese Physics B》 SCIE EI CAS CSCD 2017年第4期96-101,共6页
Hardy's theorem on nonlocality has been verified by a series of experiments with two-qubit entangled pure states.However,in this paper we demonstrate the experimental test of the theorem by using the two-photon entan... Hardy's theorem on nonlocality has been verified by a series of experiments with two-qubit entangled pure states.However,in this paper we demonstrate the experimental test of the theorem by using the two-photon entangled mixed states.We first investigate the generic logic in Hardy's proof of nonlocality,which can be applied for arbitrary two-qubit mixed polarization entangled states and can be reduced naturally to the well-known logic tested successfully by the previous pure state experiments.Then,the optimized violations of locality for various experimental parameters are delivered by the numerical method.Finally,the logic argued above for testing Hardy's theorem on nonlocality is demonstrated experimentally by using the mixed entangled-photon pairs generated via pumping two type-I BBO crystals.Our experimental results shows that Hardy's proof of nonlocality can also be verified with two-qubit polarization entangled mixed states,with a violation of about 3.4 standard deviations. 展开更多
关键词 Hardy's theorem NONLOCALITY entangled mixed state spontaneous parametric down conversion (SPDC)
下载PDF
Entanglement evolution of three-qubit mixed states in multipartite cavity-reservoir systems 被引量:1
4
作者 许景周 郭金宝 +2 位作者 文伟 白彦魁 闫凤利 《Chinese Physics B》 SCIE EI CAS CSCD 2012年第8期44-50,共7页
We analyze the multipartite entanglement evolution of three-qubit mixed states composed of a GHZ state and a W state. For a composite system consisting of three cavities interacting with independent reservoirs, it is ... We analyze the multipartite entanglement evolution of three-qubit mixed states composed of a GHZ state and a W state. For a composite system consisting of three cavities interacting with independent reservoirs, it is shown that the entanglement evolution is restricted by a set of monogamy relations. Furthermore, as quantified by the negativity, the entanglement dynamical property of the mixed entangled state of cavity photons is investigated. It is found that the three cavity photons can exhibit the phenomenon of entanglement sudden death (ESD). However, compared with the evolution of a generalized three-qubit GHZ state which has the equal initial entanglement, the ESD time of mixed states is later than that of the pure state. Finally, we discuss the entanglement distribution in the multipartite system, and point out the intrinsic relation between the ESD of cavity photons and the entanglement sudden birth of reservoirs. 展开更多
关键词 entanglement evolution three-qubit mixed states cavity-reservoir systems
下载PDF
WEAK FORMULATION OF MIXED STATE EQUATION ANDBOUNDARY VALUE PROBLEM OF LAMINATEDCYLINDRICAL SHELL
5
作者 丁克伟 唐立民 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 1999年第2期128-134,共7页
Weak formulation of mixed state equations including boundary conditions are presented in a cylindrical coordinate system by introducing Hellinger-Reissner variational principle. Analytical solutions are obtained for l... Weak formulation of mixed state equations including boundary conditions are presented in a cylindrical coordinate system by introducing Hellinger-Reissner variational principle. Analytical solutions are obtained for laminated cylindrical shell by means of state space method. The present study extends and unifies the solution of laminated shells. 展开更多
关键词 mixed state equation state space cylindrical shell weak formulation boundary value problem
下载PDF
Fidelity between Gaussian mixed states with quantum state quadrature variances
6
作者 张海龙 周淳 +1 位作者 史建红 鲍皖苏 《Chinese Physics B》 SCIE EI CAS CSCD 2016年第4期57-62,共6页
In this paper, from the original definition of fidelity in a pure state, we first give a well-defined expansion fidelity between two Gaussian mixed states. It is related to the variances of output and input states in ... In this paper, from the original definition of fidelity in a pure state, we first give a well-defined expansion fidelity between two Gaussian mixed states. It is related to the variances of output and input states in quantum information pro- cessing. It is convenient to quantify the quantum teleportation (quantum clone) experiment since the variances of the input (output) state are measurable. Furthermore, we also give a conclusion that the fidelity of a pure input state is smaller than the fidelity of a mixed input state in the same quantum information processing. 展开更多
关键词 FIDELITY mixed state quantum clone quantum information processing
下载PDF
Mixed State and High Effective Utilization of Pilbara Blending Iron Ore Powder 被引量:7
7
作者 CAO Yong-guo WU Sheng-li HAN Hong-liang WANG Hong-wei XUE Fang LIU Xiao-qin 《Journal of Iron and Steel Research(International)》 SCIE EI CAS CSCD 2011年第9期1-5,共5页
Pilbara blending iron ore powder (PB powder) is blending ores with good and poor quality iron ores, so how to use PB power effectively is a problem. The self-characteristics of PB powder and its single-components we... Pilbara blending iron ore powder (PB powder) is blending ores with good and poor quality iron ores, so how to use PB power effectively is a problem. The self-characteristics of PB powder and its single-components were studied respectively such as the macroscopic properties, microscopic properties, and high-temperature properties the behavior and effect in the sintering were mastered. Then based on the new ore-proportioning idea of iron ores sintering characteristics complementary, the principles on the effective use of PB powder were discussed, and was fur ther validated through the sintering pot test and industrial production. The results show that PB powder is composed of three kinds of iron ore, and the sintering characteristics of different iron ores are obviously discrepant. With the ore-proportioning optimization based on the iron ores sintering characteristics complementary, the proportion of PB iron ore powder can be increased to more than 45 %. 展开更多
关键词 Pilbara blending ore sintering mixed state high effective utilization
原文传递
Wave Period Distributions in Non-Gaussian Mixed Sea States
8
作者 王迎光 《China Ocean Engineering》 SCIE EI CSCD 2013年第6期809-820,共12页
The wave period probability densities in non-Gaussian mixed sea states are calculated by utilizing a transformed Gaussian process method. The transformation relating the non-Gaussian process and the original Gaussian ... The wave period probability densities in non-Gaussian mixed sea states are calculated by utilizing a transformed Gaussian process method. The transformation relating the non-Gaussian process and the original Gaussian process is obtained based on the equivalence of the level up-crossing rates of the two processes. A saddle point approximation procedure is applied for calculating the level up-crossing rates in this study. The accuracy and efficiency of the transformed Gaussian process method are validated by comparing the results predicted by using the method with those predicted by the Monte Carlo simulation method. 展开更多
关键词 wave period mixed sea state NON-GAUSSIAN saddle point approximation Monte Carlo simulation
下载PDF
Social Advantage with Mixed Entangled States
9
作者 Aritra Das Pratyusha Chowdhury 《Journal of Quantum Information Science》 2020年第2期11-22,共12页
It has been extensively shown in past literature that Bayesian game theory and quantum non-locality have strong ties between them. Pure entangled states have been used, in both common and conflict interest games, to g... It has been extensively shown in past literature that Bayesian game theory and quantum non-locality have strong ties between them. Pure entangled states have been used, in both common and conflict interest games, to gain advantageous payoffs, both at the individual and social level. In this paper, we construct a game for a mixed entangled state such that this state gives higher payoffs than classically possible, both at the individual level and the social level. Also, we use the I-3322 inequality so that states that aren’t useful advice for the Bell-CHSH<sup>1</sup> inequality can also be used. Finally, the measurement setting we use is a restricted social welfare strategy (given this particular state). 展开更多
关键词 Non-Local Games mixed Entangled states Social-Welfare-Solution
下载PDF
Mixedness of the N-qubit states with exchange symmetry
10
作者 胡明亮 惠小强 《Chinese Physics B》 SCIE EI CAS CSCD 2008年第10期3559-3564,共6页
The mixedness of the N-qubit quantum states with exchange symmetry has been studied, and the results show that the linear entropy of the single qubit reduced density matrix (RDM), which can describe the mixedness, i... The mixedness of the N-qubit quantum states with exchange symmetry has been studied, and the results show that the linear entropy of the single qubit reduced density matrix (RDM), which can describe the mixedness, is completely determined by the expectation values 〈Sz〉 and 〈S±〉 for both the pure and the mixed states. The mixedness of the pure states can be used to describe the bipartite entanglement, as an example we have calculated the mixedness of the Dicke state and the spin squeezed Kitagawa-Ueda state. For the mixed states, we determine the mixedness properties of both the ground states and the thermal states in mean-field clusters of spin-1/2 particles interacting via the anisotropy Heisenberg XXZ interaction, and found for the ferromagnetic case (J 〈 0), the mixedness will approximate to the pairwise entanglement when the anisotropic parameter △ 〉 △c. 展开更多
关键词 mixedness linear entropy symmetric quantum state
下载PDF
A note on local unitary equivalence of isotropic-like states
11
作者 张廷桂 华波波 +2 位作者 李明 赵明镜 杨红 《Chinese Physics B》 SCIE EI CAS CSCD 2015年第12期228-231,共4页
We consider the local unitary equivalence of a class of quantum states in a bipartite case and a multipartite case. The necessary and sufficient condition is presented. As special cases, the local unitary equivalent c... We consider the local unitary equivalence of a class of quantum states in a bipartite case and a multipartite case. The necessary and sufficient condition is presented. As special cases, the local unitary equivalent classes of isotropic state and Werner state are provided. Then we study the local unitary similar equivalence of this class of quantum states and analyze the necessary and sufficient condition. 展开更多
关键词 mixed state local unitary equivalence local unitary similar equivalence
下载PDF
Model Analysis of Influences of Aerosol Mixing State upon Its Optical Properties in East Asia
12
作者 韩霄 张美根 +1 位作者 朱凌云 许丽人 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2013年第4期1201-1212,共12页
The air quality model system RAMS (Regional Atmospheric Modeling System)-CMAQ (Models-3 Com- munity Multi-scale Air Quality) coupled with an aerosol optical/radiative module was applied to investigate the impact o... The air quality model system RAMS (Regional Atmospheric Modeling System)-CMAQ (Models-3 Com- munity Multi-scale Air Quality) coupled with an aerosol optical/radiative module was applied to investigate the impact of different aerosol mixing states (i.e., externally mixed, half externally and half internally mixed, and internally mixed) oil radiative forcing in East Asia. The simulation results show that the aerosol optical depth (AOD) generally increased when the aerosol mixing state changed from externally mixed to internally mixed, while the single scattering albedo (SSA) decreased. Therefore, the scattering and absorption proper- ties of aerosols can be significantly affected by the change of aerosol mixing states. Comparison of simulated and observed SSAs at five AERONET (Aerosol Robotic Network) sites suggests that SSA could be better estimated by considering aerosol particles to be internally mixed. Model analysis indicates that the impact of aerosol mixing state upon aerosol direct radiative forcing (DRF) is complex. Generally, the cooling effect of aerosols over East Asia are enhanced in the northern part of East Asia (Northern China, Korean peninsula, and the surrounding area of Japan) and are reduced in the southern part of East. Asia (Sichuan Basin and Southeast China) by internal mixing process, and the variation range can reach +5 W m 2. The analysis shows that the internal mixing between inorganic salt and dust is likely the main reason that the cooling effect strengthens. Conversely, the internal nfixture of anthropogenic aerosols, including sulfate, nitrate, ammonium, black carbon, and organic carbon, could obviously weaken the cooling effect. 展开更多
关键词 aerosol optical properties internal mixing state direct radiative forcing CMAQ
下载PDF
Real-time,single-particle chemical composition,volatility and mixing state measurements of urban aerosol particles in southwest China
13
作者 Luyao Chen Junke Zhang +5 位作者 Jiaqi Li Xiaojuan Huang Yuzheng Xiang Jing Chen Tingru Pan Wei Zhang 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2024年第2期361-371,共11页
To investigate the volatility of atmospheric particulates and the evolution of other particulate properties(chemical composition,particle size distribution and mixing state)with temperature,a thermodenuder coupled wit... To investigate the volatility of atmospheric particulates and the evolution of other particulate properties(chemical composition,particle size distribution and mixing state)with temperature,a thermodenuder coupled with a single particle aerosol mass spectrometer was used to conduct continuous observations of atmospheric fine particles in Chengdu,southwest China.Because of their complex sources and secondary reaction processes,the average mass spectra of single particles contained a variety of chemical components(including organic,inorganic and metal species).When the temperature rose from room temperature to280℃,the relative areas of volatile and semi-volatile components decreased,while the relative areas of less or non-volatile components increased.Most(>80%)nitrate and sulfate existed in the form of NH_(4)NO_(3)and(NH_(4))_(2)SO_(4),and their volatilization temperatures were50–100℃and 150–280℃,respectively.The contribution of biomass burning(BB)and vehicle emission(VE)particles increased significantly at 280℃,which emphasized the important role of regional biomass burning and local motor vehicle emissions to the core of particles.With the increase in temperature,the particle size of the particles coated with volatile or semi-volatile components was reduced,and their mixing with secondary inorganic components was significantly weakened.The formation of K-nitrate(KNO_(3))and K-sulfate(KSO_(4))particles was dominated by liquid-phase processes and photochemical reactions,respectively.Reducing KNO_(3)and BB particles is the key to improving visibility.These new results are helpful towards better understanding the initial sources,pollution formation mechanisms and climatic effects of fine particulate matter in this megacity in southwest China. 展开更多
关键词 Atmospheric fine particles TD-SPAMS Chemical composition VOLATILITY Mixing state
原文传递
Mixing states and secondary formation processes of organic nitrogen-containing single particles in Guangzhou,China
14
作者 Lijun Yun Chunlei Cheng +9 位作者 Suxia Yang Zaihua Wang Mei Li Qi En Zhong LiyuanMao Sulin Liu Xiaoya Cheng Duanying Chen Fan Yang Zhen Zhou 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2024年第4期62-73,共12页
Organic nitrogen(ON)compounds play a significant role in the light absorption of brown carbon and the formation of organic aerosols,however,the mixing state,secondary formation processes,and influencing factors of ON ... Organic nitrogen(ON)compounds play a significant role in the light absorption of brown carbon and the formation of organic aerosols,however,the mixing state,secondary formation processes,and influencing factors of ON compounds are still unclear.This paper reports on the mixing state of ON-containing particles based on measurements obtained using a highperformance single particle aerosol mass spectrometer in January 2020 in Guangzhou.The ON-containing particles accounted for 21% of the total detected single particles,and the particle count and number fraction of the ON-containing particles were two times higher at night than during the day.The prominent increase in the content of ON-containing particles with the enhancement of NO_xmainly occurred at night,and accompanied by high relative humidity and nitrate,which were associated with heterogeneous reactions between organics and gaseous NO_(x)and/or NO_(3)radical.The synchronous decreases in ON-containing particles and the mass absorption coefficient of water-soluble extracts at 365 nm in the afternoon may be associated with photo-bleaching of the ON species in the particles.In addition,the positive matrix factorization analysis found five factors dominated the formation processes of ON particles,and the nitrate factor(33%)mainly contributed to the production of ON particles at night.The results of this study provide unique insights into the mixing states and secondary formation processes of the ON-containing particles. 展开更多
关键词 Organic nitrogen compounds Single particles Mixing state Secondary formation Nighttime chemistry
原文传递
One-year observation of the mixing states of oxygenated organics-containing single particles in Guangzhou,China
15
作者 Liyuan Mao Suxia Yang +6 位作者 Xiaoya Cheng Sulin Liu Duanying Chen Zhen Zhou Mei Li Chenglei Pei Chunlei Cheng 《Frontiers of Environmental Science & Engineering》 SCIE EI CSCD 2024年第5期155-169,共15页
Oxygenated organic molecules(OOMs)play an important role in the formation of secondary organic aerosols(SOAs),but the mixing states of OOMs are still unclear.This study investigates the mixing states of OOM-containing... Oxygenated organic molecules(OOMs)play an important role in the formation of secondary organic aerosols(SOAs),but the mixing states of OOMs are still unclear.This study investigates the mixing states of OOM-containing single particles from the measurements taken using a single particle aerosol mass spectrometer in Guangzhou,China in 2022.Generally,the particle counts of OOM particles and the mass concentration of secondary organic carbon(SOC)exhibited similar temporal trends throughout the entire year.The OOM particles were consistently enriched in secondary ions,including 16O−,26CN−,46NO2−,62NO3−,and 97HSO4−.In contrast,the number fractions and diurnal patterns of OOM particles among the total detected particles showed similar distributions in August and October;however,the SOC ratios in fine particulate matter were quite different,suggesting that there were different mixing states of single-particle oxygenated organics.In addition,further classification results indicated that the OOM particles were more aged in October than August,even though the SOC ratios were higher in August.Furthermore,the distribution of hydrocarbon fragments exhibited a notable decrease from January to October,emphasizing the more aged state of the organics in October.In addition,the sharp increase in elemental carbon(EC)-OOM particles in the afternoon in October suggests the potential role of EC in the aging process of organics.Overall,in contrast to the bulk analysis of SOC mass concentration,the mixing states of the OOM particles provide insights into the formation process of SOAs in field studies. 展开更多
关键词 Oxygenated organics Single particles Mixing state Secondary formation PHOTOCHEMISTRY
原文传递
A geometric phase for superconducting qubits under the decoherence effect
16
作者 S.Abdel-Khalek K.Berrada +1 位作者 Mohamed A.El-Sayed M.Abel-Aty 《Chinese Physics B》 SCIE EI CAS CSCD 2013年第10期88-93,共6页
We propose a relaxation rate or dissipative cavity-based parameters that can be used as indicators of the stationary limit of a mixed state geometric phase. We perform our considerations for the system of a supercondu... We propose a relaxation rate or dissipative cavity-based parameters that can be used as indicators of the stationary limit of a mixed state geometric phase. We perform our considerations for the system of a superconducting qubit in an open transmission line or interacting with a dissipative cavity. This system is very useful for performing an effective quantum computation by exhibiting the long collapse time of the geometric phase. It is shown that the geometric phase in the stationary limit does not depend on interaction time if the decay time exceeds an upper bound. 展开更多
关键词 superconducting-qubit meometric phase mixed state DECOHERENCE
下载PDF
Energy Losses in Superconductors
17
作者 Charles Dean Milind N. Kunchur 《Journal of Power and Energy Engineering》 2016年第5期20-24,共5页
Absence of macroscopic resistance is the most essential trait of superconductors for their practical applications. Yet several mechanisms lead to dissipation in the superconducting state such as weak links, fluctuatio... Absence of macroscopic resistance is the most essential trait of superconductors for their practical applications. Yet several mechanisms lead to dissipation in the superconducting state such as weak links, fluctuations, and the motion of flux vortices in the mixed state of type II materials. Thus it is of practical as well as fundamental interest to explore these mechanisms to the fullest extent and to learn how to control them. Regarding the control of flux motion, most research efforts aim at preventing flux motion by introducing a variety of pinning strategies. In the present work, we discuss the circumstances under which it is possible to exclude vortices in the first place, or to short their motion through intrinsic multi-band effects. Experimental results on two model systems, molybdenum-germanium and magnesium diboride films, are presented to support these strategies. 展开更多
关键词 mixed state VORTICES Critical Current Two-Band
下载PDF
Isospin and Symmetry Structure in ^(36)Ar 被引量:3
18
作者 BAI Hong-Bo ZHANG Jin-Fu CAO Wan-Cang LLi-Jun Zhaorigt DONG Hong-Fei Department of Physics,Chifeng University,Chifeng 024001,ChinaLI Yan-Song Department of Physics,Tsinghua University,Beijing 100084,China 《Communications in Theoretical Physics》 SCIE CAS CSCD 2007年第12期1067-1071,共5页
The interacting boson model-3(IBM-3) has been used to study the isospin excitation states and electromag-netic transitions for ^(36)Ar nucleus.The mixed symmetry states and superdeformed band at low spin are also anal... The interacting boson model-3(IBM-3) has been used to study the isospin excitation states and electromag-netic transitions for ^(36)Ar nucleus.The mixed symmetry states and superdeformed band at low spin are also analyzed.The theoretical calculations are in agreement with experimental data,and the ^(36)Ar is superdeformed rotational nucleusclose to the SU(3) limit.The present calcula,tions indicate that the 2_4^+ state is the lowest mixed symmetry state and thelowest isospin T=1 excitation state and at about 6.2 MeV,and the bandhead of superdeformed band is 0_2^+ state. 展开更多
关键词 IBM-3 energy level ISOSPIN mixed symmetry states electromagnetic transitions
下载PDF
Recent research progress on mixed valence state tungsten based materials 被引量:6
19
作者 Shu Yin Yusuke Asakura 《Tungsten》 2019年第1期5-18,共14页
Synthesis and characterization of tungsten based mixed valence state nanoparticles and their novel applications are reviewed.The mixed valence state tungsten based homogeneous nanomaterials such as bronze structure M_... Synthesis and characterization of tungsten based mixed valence state nanoparticles and their novel applications are reviewed.The mixed valence state tungsten based homogeneous nanomaterials such as bronze structure M_(x)WO_(3)(M=Na^(+),K^(+),Rb^(+),Cs^(+),NH_(4)^(+),etc.)and tungsten sub-oxide W_(18)O_(49) possess excellent infrared(IR)light shielding property,implying their great potential applications on heat ray shielding and indoor energy saving effect in summer season.Also,some novel properties such as electric conductivity,bio thermal therapy function and electrochromic properties of mixed valence state tungsten based materials are introduced.The design of components,formation of composites and structure control of thin films are expected to realize the property enhancement and candidates for practice application as window materials.The multifunc-tionality of the mixed valence state based composites also implies great potential on novel applications of various building materials. 展开更多
关键词 Tungsten bronze mixed valence state Smart window Infrared(IR)light shielding THERMOCHROMIC Photothermal ablation therapy(PTA) Multifunctionality
原文传递
Mixed symmetry states and isospin excitation in the N =Z nucleus ^(28)Si 被引量:1
20
作者 吕立君 Al-Khudair Falih H +1 位作者 张进富 白洪波 《Chinese Physics C》 SCIE CAS CSCD 2009年第S1期46-48,共3页
The interacting boson model with isospin (IBM-3) has been used to study the isospin excitation states and mixed symmetry states at low spin for 28Si. The theoretical calculations are in agreement with experimental dat... The interacting boson model with isospin (IBM-3) has been used to study the isospin excitation states and mixed symmetry states at low spin for 28Si. The theoretical calculations are in agreement with experimental data. The theoretical results show that the 81+ energy is 14.73 MeV. 展开更多
关键词 IBM-3 energy level ISOSPIN mixed symmetry states
原文传递
上一页 1 2 下一页 到第
使用帮助 返回顶部