期刊文献+
共找到77,444篇文章
< 1 2 250 >
每页显示 20 50 100
Discussion on the Operation of Urban Domestic Sewage Treatment Facilities : A Case Study of Guangdong Province 预览
1
作者 Du Shuntao Yang Shewei +1 位作者 Guo Qian Huang Zhihua 《气象与环境研究:英文版》 CAS 2019年第4期110-113,117共5页
Urban sewage treatment facility is an important ways to control polluted domestic water. The operation of urban sewage treatment facilities is good or not, and whether the effectiveness of pollutant emission reduction... Urban sewage treatment facility is an important ways to control polluted domestic water. The operation of urban sewage treatment facilities is good or not, and whether the effectiveness of pollutant emission reduction can be exerted play a significant role in reducing the pollution of living sources. Nowadays the operation of urban sewage treatment facilities is mainly evaluated by the load rate. However, due to the failure to fully implement the reformation of the rainwater and polluted water in Guangdong Province, the domestic sewage is mixed with rainwater during the rainy season and is included in the treatment of urban sewage treatment facilities. Therefore, it is not objective to evaluate the operation of sewage treatment facilities using only the load rate of sewage treatment. According to the situation of Guangdong Province, the load rates of COD, ammonia nitrogen and total phosphorus in domestic sewage and load rate of sewage treatment were included in the evaluation, and 20 urban sewage treatment facilities were selected as research objects. The operation situations and emission reduction benefits of urban sewage treatment facilities in different regions of Guangdong Province were roughly evaluated. 展开更多
关键词 Operation evaluation URBAN SEWAGE TREATMENT facilities LOAD RATE of SEWAGE TREATMENT LOAD RATE of COD LOAD RATE of AMMONIA nitrogen LOAD RATE of total phosphorus
在线阅读 下载PDF
原油转驳船海上作业定位能力需求分析 预览
2
作者 胡开业 丁勇 +2 位作者 王宏伟 熊大鹏 杨笛 《船舶与海洋工程学报:英文版》 CSCD 2019年第2期205-212,共8页
In response to the development of deep-sea oil and gas resources,which require a high degree of cooperation by crude oil transportation equipment,a new type of ship known as the cargo transfer vessel(CTV)has been deve... In response to the development of deep-sea oil and gas resources,which require a high degree of cooperation by crude oil transportation equipment,a new type of ship known as the cargo transfer vessel(CTV)has been developed.To provide a theoretical reference for the design and equipment of the CTV’s dynamic positioning system,in this paper,we take the new deepwater CTVas the study object and theoretically and numerically analyze its operation,wind load,current load,wave load,and navigational resistance in a range of Brazilian sea conditions with respect to its positioning and towing modes.We confirm that our proposed method can successfully calculate the total environmental load of the CTVand that the CTV is able to operate normally under the designed sea conditions. 展开更多
关键词 CARGO TRANSFER VESSEL Wind LOAD Current LOAD Wave LOAD DP CAPABILITY Oil TRANSFER operation
在线阅读 下载PDF
基于PLR-TD算法的电网负荷季节临界变化条件研究 预览
3
作者 万顺 桂宁 +1 位作者 陈家静 陈小龙 《安徽电力》 2019年第1期25-29,共5页
一年中季节的变化,包括春季向夏季、秋季向冬季的转变,均令合肥电网的负荷有较大的增加,考验电网的承载能力。因此,通过探究外界条件的变化或者电网本身的指标的变化,采用PLR-TD算法对电网负荷影响条件中的时间、温度和峰谷差率等条件... 一年中季节的变化,包括春季向夏季、秋季向冬季的转变,均令合肥电网的负荷有较大的增加,考验电网的承载能力。因此,通过探究外界条件的变化或者电网本身的指标的变化,采用PLR-TD算法对电网负荷影响条件中的时间、温度和峰谷差率等条件进行分析,综合度量合肥市电网季节变化的临界条件,对基础负荷的取值、负荷预测以及电网负荷的监测均有一定的实际意义。 展开更多
关键词 负荷 负荷预测 PLR-TD算法 峰谷差率 迎峰度冬
在线阅读 下载PDF
Reactive power deployment and cost benefit analysis in DNO operated distribution electricity markets with D-STATCOM
4
作者 Atma Ram GUPTA Ashwani KUMAR 《能源前沿:英文版》 CSCD 2019年第1期86-98,共13页
The aim of this paper is to analyze unbalanced radial distribution systems(UBRDS)with the distribution static compensator(D-STATCOM).The main objectives of this paper are D-STATCOM allocation in UBRDS with an objectiv... The aim of this paper is to analyze unbalanced radial distribution systems(UBRDS)with the distribution static compensator(D-STATCOM).The main objectives of this paper are D-STATCOM allocation in UBRDS with an objective of providing reactive power support to enhance voltage profile and reduce line losses of the distribution network,determination of optimal D-STATCOM rating subjected to minimization of total cost,and impact of D-STATCOM placement on improving power factor and savings in cost of energy loss.The analysis is conducted on a large industrial load model with light,medium and high loading scenarios.Further,the impact of load growth is also considered for better planning of the power distribution system.The results are obtained on standard 25-bus UBRDS to check the feasibility of the proposed methodology. 展开更多
关键词 unbalanced DISTRIBUTION system D-STATCOM VOLTAGE sensitivity index LOAD models LOAD growth DISTRIBUTION network operator(DNO)
基于Haar小波与ARIMAX模型进行短期负荷预测 预览
5
作者 党亚峥 徐腾飞 高岩 《上海理工大学学报》 CAS CSCD 北大核心 2019年第1期64-70,共7页
为了提高对非稳态负荷的预测精度,提出了基于Haar小波分析和ARIMAX模型的短期负荷预测方案。首先,通过Haar小波将高频信息序列与低频信息序列分别从电价与负荷序列中分解出来;其次,分别利用电价序列的高、低频序列对负荷序列的高、低频... 为了提高对非稳态负荷的预测精度,提出了基于Haar小波分析和ARIMAX模型的短期负荷预测方案。首先,通过Haar小波将高频信息序列与低频信息序列分别从电价与负荷序列中分解出来;其次,分别利用电价序列的高、低频序列对负荷序列的高、低频序列进行ARIMAX模型构建和预测;最后,将含有电价信息的高、低频负荷预测值进行Haar小波重构,得到负荷序列的预测值。通过实例验证表明,本文采用ARIMAX模型添加的电价信息,弥补了多次预测产生的误差,对短期负荷的预测精度高于传统时间序列方法。 展开更多
关键词 HAAR小波 ARIMAX模型 电价信息 负荷 短期负荷预测
在线阅读 下载PDF
A day-ahead scheduling framework for thermostatically controlled loads with thermal inertia and thermal comfort model 预览
6
作者 Yingying CHEN Fengji LUO +3 位作者 Zhaoyang DONG Ke MENG Gianluca RANZI Kit Po WONG 《现代电力系统与清洁能源学报(英文)》 CSCD 2019年第3期568-578,共11页
This paper proposes a day-ahead dispatch framework of thermostatically controlled loads(TCLs) for system peak load reduction. The proposed day-ahead scheduling framework estimates the user’s indoor thermal comfort de... This paper proposes a day-ahead dispatch framework of thermostatically controlled loads(TCLs) for system peak load reduction. The proposed day-ahead scheduling framework estimates the user’s indoor thermal comfort degree through the building thermal inertia modelling. Based on the thermal comfort estimation, a dayahead TCL scheduling model is formulated, which consists of 3 stages: TCL aggregator estimates maximal controllable TCL capacities at each scheduling time interval by solving a optimization model;[ the system operator performs the day-ahead system dispatch to determine the load shedding instruction for each aggregator;and ′the TCL aggregator schedules the ON/OFFcontrol actions of the TCL groups based on the instruction from the system operator. A heuristic based optimization method, history driven differential evolution(HDDE)algorithm, is employed to solve the day-ahead dispatch model of the TCL aggregator side. Simulations are conducted to validate the proposed model. 展开更多
关键词 Thermostatically controlled LOAD DEMAND side management Thermal COMFORT model DEMAND response (DR) Direct LOAD control(DLC)
在线阅读 下载PDF
一种用于6LoWPAN的多路径路由协议 预览
7
作者 邓海良 《电脑知识与技术:学术版》 2019年第8期31-32,58,共3页
分析6LoWPAN网络的特点及其对路由协议的要求。提出一种基于LOAD路由协议的多路径改进方案OS-LOAD,引入按最优路由与次优路由的路由代价比实现多路径传输数据的思想,并利用NS2对该方案进行仿真分析。结果表明,本方案在分组投递率、传输... 分析6LoWPAN网络的特点及其对路由协议的要求。提出一种基于LOAD路由协议的多路径改进方案OS-LOAD,引入按最优路由与次优路由的路由代价比实现多路径传输数据的思想,并利用NS2对该方案进行仿真分析。结果表明,本方案在分组投递率、传输时延、整网生存时间等方面具有更大的优势。 展开更多
关键词 6LoWPAN LOAD OS-LOAD NS2仿真
在线阅读 下载PDF
Effect of vertical stress rest period on deformation behaviour of unbound granular materials:Experimental and numerical investigations 预览
8
作者 Ali Alnedawi Kali Prasad Nepal +1 位作者 Riyadh Al-Ameri Mohanad Alabdullah 《岩石力学与岩土工程学报:英文版》 CSCD 2019年第1期172-180,共9页
Repeated load triaxial test is used to assess the deformation behaviour of unbound granular materials(UGMs)in flexible road pavements.Repeated load pulse characteristics(i.e.shape,loading period and rest period)are th... Repeated load triaxial test is used to assess the deformation behaviour of unbound granular materials(UGMs)in flexible road pavements.Repeated load pulse characteristics(i.e.shape,loading period and rest period)are the stress configurations used in the experimental set-up to simulate the passing axle loads.Some researchers and standard testing protocols suggest a rest period of varying durations after a loading phase.A thorough review of existing literature and practises has revealed that there is no agreement about the effect of the rest period of vertical stress pulse on the deformation behaviour of the UGMs.Therefore,the main objective of this study is to investigate the effect of repeated stress rest period on the deformation behaviour of UGMs experimentally.Experiments are conducted,both with and without rest period,using basalt and granite crushed rocks from Victoria,Australia.Furthermore,in order to gain insight into the effect of the rest period,finite element modelling is also developed.Both the experimental and modelling results show that the rest period has a noticeable effect on both resilient and permanent deformation behaviours of UGMs.It is,therefore,recommended to take extra precautions while adopting a particular standard testing protocol and to supplement the results by additional tests with different loading configurations. 展开更多
关键词 Flexible PAVEMENT Unbound GRANULAR materials(UGMs) Repeated load TRIAXIAL test Resilient MODULUS PERMANENT deformation Finite element modelling
在线阅读 下载PDF
基于ANSYS的中空阀体多向模锻工艺研究
9
作者 陶静萍 《热加工工艺》 北大核心 2019年第9期183-185,共3页
中空阀体在高压环境中工作,其对锻件的力学性能提出了高要求。本文对比了三种中空阀体件模锻工艺对模具载荷的影响。从填充率和锻件应力两方面分析了右端盖模锻工艺对锻造质量的影响。结果表明,右端盖模锻工艺的模具载荷最小,应力分布均... 中空阀体在高压环境中工作,其对锻件的力学性能提出了高要求。本文对比了三种中空阀体件模锻工艺对模具载荷的影响。从填充率和锻件应力两方面分析了右端盖模锻工艺对锻造质量的影响。结果表明,右端盖模锻工艺的模具载荷最小,应力分布均匀,锻造质量最好。 展开更多
关键词 阀体 模锻 载荷 应力 ANSYS软件
Constant temperature control of tundish induction heating power supply for metallurgical manufacturing
10
作者 Yufei YUE Qianming XU +1 位作者 Peng GUO An LUO 《能源前沿:英文版》 CSCD 2019年第1期16-26,共11页
The tundish induction heating power supply(TIHPS)is one of the most important equipment in the continuous casting process for metallurgical manufacturing.Specially,the constant temperature control is greatly significa... The tundish induction heating power supply(TIHPS)is one of the most important equipment in the continuous casting process for metallurgical manufacturing.Specially,the constant temperature control is greatly significant for metallurgical manufacturing.In terms of the relationship between TIH load temperature and output power of TIHPS,the constant temperature control can be realized by power control.In this paper,a TIHPS structure with three-phase PWM rectifiers and full-bridge cascaded inverter is proposed.Besides,an input harmonic current blocking strategy and a load voltage feedforward control are also proposed to realize constant temperature control.To meet the requirement of the system,controller parameters are designed properly.Experiments are con?ducted to validate the feasibility and effectiveness of the proposed TIHPS topology and the control methods. 展开更多
关键词 TUNDISH induction heating power supply(TIHPS) CONSTANT temperature control INPUT HARMONIC current BLOCKING load voltage FEEDFORWARD
Effect of axial load and transverse reinforcements on the seismic performance of reinforced concrete columns
11
作者 Mounir Ait BELKACEM Hakim BECHTOULA +1 位作者 Nouredine BOURAHLA Adel Ait BELKACEM 《结构与土木工程前沿:英文版》 EI CSCD 2019年第4期831-851,共21页
The aim of this research is to assess the seismic performance of reinforced concrete columns under different axial load and transverse reinforcement ratios. These two parameters are very important as for the ductility... The aim of this research is to assess the seismic performance of reinforced concrete columns under different axial load and transverse reinforcement ratios. These two parameters are very important as for the ductility, strength, stiffness, and energy dissipation capacity for a given reinforced concrete column. Effects of variable axial load ratio and transverse reinforcement ratio on the seismic performance of reinforced concrete columns are thoroughly analyzed. The finite element computer program Seismo-Structure was used to perform the analysis of series of reinforced concrete columns tested by the second author and other researchers. In order to reflect the reality and grasp the actual behavior of the specimens, special attention was paid to select the models for concrete, confined concrete, and steel components. Good agreements were obtained between the experimental and the analytical results either for the lateral force-drift relationships or for the damage progress prediction at different stages of the loading. 展开更多
关键词 REINFORCED concrete COLUMNS AXIAL load TRANSVERSE REINFORCEMENT DUCTILITY
基于中欧规范的框架结构设计荷载对比 预览
12
作者 邓果 《黑龙江交通科技》 2019年第9期82-84,86共4页
与中国规范的操作性强相比,欧洲规范的理论性较强;同时使用欧洲规范的成员较多,各国设计思路、工程环境、经济水平和行政政策不同,造成欧洲规范在保证同一性的同时,对于一些规范条文和参数,也建议各国根据自身情况选取使用。结合阿尔及... 与中国规范的操作性强相比,欧洲规范的理论性较强;同时使用欧洲规范的成员较多,各国设计思路、工程环境、经济水平和行政政策不同,造成欧洲规范在保证同一性的同时,对于一些规范条文和参数,也建议各国根据自身情况选取使用。结合阿尔及利亚某项目,对比了欧洲规范、中国规范以及阿尔及利亚当地规范,分析各规范之间的异同,为框架结构设计荷载计算提供参考。 展开更多
关键词 框架结构 荷载 欧洲规范 中国规范
在线阅读 下载PDF
某滑移门车门把手力研究 预览
13
作者 刘琳 赵宇馨 季晓丽 《汽车零部件》 2019年第5期31-35,共5页
汽车滑移门在设计阶段需要做耐久理论分析,一般会在外把手上施加某个载荷,进行滑移门钣金及滚轮、支架等零件的分析。为了确定该载荷的大小,通过测量工装收集一定数量顾客实际关门时的数据,并绘制出时间和力的曲线。分析后得到某关门速... 汽车滑移门在设计阶段需要做耐久理论分析,一般会在外把手上施加某个载荷,进行滑移门钣金及滚轮、支架等零件的分析。为了确定该载荷的大小,通过测量工装收集一定数量顾客实际关门时的数据,并绘制出时间和力的曲线。分析后得到某关门速度下对应的关门力的曲线,为进行理论耐久分析提供了更准确的力加载曲线。 展开更多
关键词 滑移门 载荷 数据分析 力曲线
在线阅读 下载PDF
Resilient Fixed-Order Distributed Dynamic Output Feedback Load Frequency Control Design for Interconnected Multi-Area Power Systems 预览
14
作者 Ali Azarbahram Amir Amini Mahdi Sojoodi 《自动化学报:英文版》 CSCD 2019年第5期1139-1151,共13页
The paper proposes a novel H∞ load frequency control(LFC) design method for multi-area power systems based on an integral-based non-fragile distributed fixed-order dynamic output feedback(DOF) tracking-regulator cont... The paper proposes a novel H∞ load frequency control(LFC) design method for multi-area power systems based on an integral-based non-fragile distributed fixed-order dynamic output feedback(DOF) tracking-regulator control scheme. To this end, we consider a nonlinear interconnected model for multiarea power systems which also include uncertainties and timevarying communication delays. The design procedure is formulated using semi-definite programming and linear matrix inequality(LMI) method. The solution of the proposed LMIs returns necessary parameters for the tracking controllers such that the impact of model uncertainty and load disturbances are minimized. The proposed controllers are capable of receiving all or part of subsystems information, whereas the outputs of each controller are local. These controllers are designed such that the resilient stability of the overall closed-loop system is guaranteed. Simulation results are provided to verify the effectiveness of the proposed scheme. Simulation results quantify that the distributed(and decentralized) controlled system behaves well in presence of large parameter perturbations and random disturbances on the power system. 展开更多
关键词 Dynamic OUTPUT FEEDBACK CONTROL interconnected multi-area POWER systems load FREQUENCY CONTROL linear matrix INEQUALITIES POWER system CONTROL
在线阅读 下载PDF
百千瓦中型变速变桨风电机组叶片设计研究
15
作者 徐立军 王维庆 《热科学与技术》 CAS CSCD 北大核心 2019年第1期66-71,共6页
百千瓦级叶片一般采用定桨方式运行,依靠叶片失速进行功率控制,机组运行过程中无法维持较高的效率。基于100kW变速变桨机组的运行特征,提出了一种100kW级中型叶片的设计方法。气动设计采用了BEM方法,利用Harp_opt中的优化算法获得较高... 百千瓦级叶片一般采用定桨方式运行,依靠叶片失速进行功率控制,机组运行过程中无法维持较高的效率。基于100kW变速变桨机组的运行特征,提出了一种100kW级中型叶片的设计方法。气动设计采用了BEM方法,利用Harp_opt中的优化算法获得较高的气动性能;结构及载荷设计参考IEC标准进行,采用Focus进行铺层设计及结构特性分析。所设计叶片的长度为10.029m左右,极限及疲劳载荷特性满足GL IIA类风场的运行要求。 展开更多
关键词 中型风电叶片 设计方法 载荷 变速 变桨
碳源和微生物协同负载体系建构的研究 预览
16
作者 张燕妮 祝余辉 +6 位作者 杨柳 任迎港 张媛媛 伊佳伟 夏远乾 方晓军 孙燕 《浙江化工》 CAS 2019年第7期33-36,共4页
通过改变醋酸钠和纤维素的比例,在不同的条件下制得微球粒子,并利用滴定分析原理测得该微球粒子中醋酸钠的包埋率和释放率。在此基础上加入竹炭和菌粉,用平板检测法来分析碳源与微生物的协同负载作用。研究证明,构建微生物固定化/碳源... 通过改变醋酸钠和纤维素的比例,在不同的条件下制得微球粒子,并利用滴定分析原理测得该微球粒子中醋酸钠的包埋率和释放率。在此基础上加入竹炭和菌粉,用平板检测法来分析碳源与微生物的协同负载作用。研究证明,构建微生物固定化/碳源缓释协同作用较为成功,碳源显示较好的缓释性能;微生物成功被包埋进去,并具有良好的繁殖能力。 展开更多
关键词 醋酸钠 乙基纤维素 竹炭 负载
在线阅读 免费下载
共轴刚性旋翼复合式高速直升机操纵与载荷研究 预览
17
作者 吴裕平 习娟 《南京航空航天大学学报》 CAS CSCD 北大核心 2019年第2期166-170,共5页
针对共轴刚性旋翼复合式高速直升机构型,分析了其操纵特点,提出两种配平操纵方式:切换操纵方式和耦合操纵方式,并分析了两种操纵方式的优缺点。从多操纵面的冗余控制出发,对耦合操纵方式的操纵规律进行了配平分析,并根据配平情况评估了... 针对共轴刚性旋翼复合式高速直升机构型,分析了其操纵特点,提出两种配平操纵方式:切换操纵方式和耦合操纵方式,并分析了两种操纵方式的优缺点。从多操纵面的冗余控制出发,对耦合操纵方式的操纵规律进行了配平分析,并根据配平情况评估了旋翼和尾推桨的载荷结果。研究结果表明,共轴刚性旋翼高速直升机旋翼的总距操纵、周期操纵与飞行速度、机身俯仰角有一定关系,旋翼载荷和常规直升机相比大幅增加,同时和机身俯仰角也密切相关。 展开更多
关键词 共轴刚性旋翼 操纵 载荷 旋翼 配平
在线阅读 下载PDF
低压配变台区负荷及无功智能平衡实现方法 预览
18
作者 鲁文军 傅明 +2 位作者 张嘉辉 李若 江天天 《电力系统及其自动化学报》 CSCD 北大核心 2019年第5期124-131,共8页
基于低压配变台区严重的电能质量问题,提出一种低压配变台区负荷及无功智能平衡实现方法。给出了基于改进九域法的终端用户分散式无功补偿策略;建立了以三相负荷不平衡度最小、低压负荷相间切换次数最少的多目标最优负荷换相数学模型,... 基于低压配变台区严重的电能质量问题,提出一种低压配变台区负荷及无功智能平衡实现方法。给出了基于改进九域法的终端用户分散式无功补偿策略;建立了以三相负荷不平衡度最小、低压负荷相间切换次数最少的多目标最优负荷换相数学模型,运用多目标二进制粒子群优化算法求解该数学模型,建立了负荷三相不平衡控制策略,通过上述方法实现了负荷及无功智能平衡。最后通过仿真算例验证了智能平衡控制算法的可靠性。 展开更多
关键词 低压配变台区 负荷 三相不平衡 无功 智能平衡 多目标二进制粒子群优化算法
在线阅读 下载PDF
考虑感应电动机稳定约束的城市综合能源系统暂态过程优化控制模型 预览
19
作者 周运斌 王卫 +4 位作者 杨俊炜 董楠 王海云 张文朝 顾大可 《可再生能源》 CAS 北大核心 2019年第9期1333-1339,共7页
针对由可再生能源或清洁能源供能的城市综合能源系统中的感应电动机,在多能源形式的供能和负荷波动及不确定性条件下的运行稳定性问题,提出了一种考虑综合能源系统中多种类可再生电源及多能源负荷协调的感应电动机临界转矩优化。首先建... 针对由可再生能源或清洁能源供能的城市综合能源系统中的感应电动机,在多能源形式的供能和负荷波动及不确定性条件下的运行稳定性问题,提出了一种考虑综合能源系统中多种类可再生电源及多能源负荷协调的感应电动机临界转矩优化。首先建立含综合能源的电网广义负荷模型;其次基于戴维南等值电路对感应电动机负荷的外部网络进行等效;最后推导感应电动机转矩方程,进而提出城市电网感应电动机暂态过程优化方法。以某城市综合能源网为例,采用BPA软件建立城市综合能源系统等值模型,仿真结果验证了文章所提方法的有效性。 展开更多
关键词 城市电网 综合能源 负荷 感应电动机 燃气轮机
在线阅读 下载PDF
高载荷作用对大鼠椎间盘退行性变的影响
20
作者 武圣达 闫晓东 +5 位作者 张舒 石菲 宫献文 周程沛 高浩然 钱济先 《中国矫形外科杂志》 CAS CSCD 北大核心 2019年第10期921-925,共5页
[目的]模拟战斗机飞行员超高加速度飞行和进行特殊战术动作时的高载荷环境,探索该环境对飞行员椎间盘退行性变的结构功能影响和潜在机制。[方法]利用动物离心机制备+6Gz组、+10Gz组高载荷下大鼠椎间盘退行性变模型各10只,通过对大鼠体重... [目的]模拟战斗机飞行员超高加速度飞行和进行特殊战术动作时的高载荷环境,探索该环境对飞行员椎间盘退行性变的结构功能影响和潜在机制。[方法]利用动物离心机制备+6Gz组、+10Gz组高载荷下大鼠椎间盘退行性变模型各10只,通过对大鼠体重、L5/6椎间盘MRI成像和HE染色三种方法,对退行性变的发生情况进行检测。[结果]随着载荷的增强,大鼠椎间盘含水量减少,高度丢失,在HE染色中发现纤维环结构破坏。[结论]大鼠椎间盘退行性变与高载荷影响有关,且随着载荷的升高,椎间盘退行性变加重。 展开更多
关键词 载荷 加速度 飞行员 椎间盘 退行性变
上一页 1 2 250 下一页 到第
使用帮助 返回顶部 意见反馈