期刊文献+
共找到367,947篇文章
< 1 2 250 >
每页显示 20 50 100
Applying design science approach to architectural design development 认领
1
作者 Rania Aburamadan Claudia Trillo 《建筑学研究前沿:英文版》 CSCD 2020年第1期216-235,共20页
Unlike research methods for social and positivist sciences,those for architectural design lack a discipline-specific conceptual framework.Performative science aims at producing outcomes for future use and therefore ne... Unlike research methods for social and positivist sciences,those for architectural design lack a discipline-specific conceptual framework.Performative science aims at producing outcomes for future use and therefore needs a robust methodological approach that encompasses different techniques and methods supporting an evidence-based architectural design development.This study suggests that design science can be successfully applied to architectural design development and provides architects and designers with a powerful tool bridging the gap between research and design.In so doing,this study explores the application of design science to implement a user-centered design approach.A design challenge is reframed within the robust framework of design science by referring to a case study on refugee shelters.The traditional method by which shelter optimization is pursued by designers is questioned by involving the final users through an ethnographic approach within the framework of design science.The design outcome produced through this process is a list of specifications allowing designers to create different architectural solutions and matching the requirements expressed by future users.The authors argue that a user-centered design outcome can be achieved and validated through design science. 展开更多
关键词 Design science Architectural design research methodology User-centered design Refugee shelter
Multidisciplinary integrated design of long-range ballistic missile using PSO algorithm 认领
2
作者 ZHENG Xu GAO Yejun +1 位作者 JINGWuxing WANG Yongsheng 《系统工程与电子技术:英文版》 SCIE EI CSCD 2020年第2期335-349,共15页
In the case of the given design variables and constraint functions, this paper is concerned with the rapid overall parameters design of trajectory, propulsion and aerodynamics for long-range ballistic missiles based o... In the case of the given design variables and constraint functions, this paper is concerned with the rapid overall parameters design of trajectory, propulsion and aerodynamics for long-range ballistic missiles based on the index of the minimum take-off mass.In contrast to the traditional subsystem independent design, this paper adopts the research idea of the combination of the subsystem independent design and the multisystem integration design.Firstly, the trajectory, propulsion and aerodynamics of the subsystem are separately designed by the engineering design, including the design of the minimum energy trajectory, the computation of propulsion system parameters, and the calculation of aerodynamic coefficient and dynamic derivative of the missile by employing the software of missile DATCOM. Then, the uniform design method is used to simplify the constraint conditions and the design variables through the integration design, and the accurate design of the optimized variables would be accomplished by adopting the uniform particle swarm optimization(PSO) algorithm. Finally, the automation design software is written for the three-stage solid ballistic missile. The take-off mass of 29 850 kg is derived by the subsystem independent design, and 20 constraints are reduced by employing the uniform design on the basis of 29 design variables and 32 constraints, and the take-off mass is dropped by 1 850 kg by applying the combination of the uniform design and PSO. The simulation results demonstrate the effectiveness and feasibility of the proposed hybrid optimization technique. 展开更多
关键词 BALLISTIC MISSILE independent DESIGN MULTIDISCIPLINARY integrated DESIGN uniform DESIGN particle SWARM optimization(PSO)
在线阅读 下载PDF
简评2019年日本外观设计法修改 认领
3
作者 傅毅冬 纪翔 《中国发明与专利》 2020年第5期114-118,共5页
2019年,日本外观设计法迎来大调整,特许厅希望借助此次修改带动强化产业竞争力。本次修改以保护期限扩大、保护对象扩大和对于日本独具特色的关联外观设计制度调整为主要内容,能够很好地满足信息时代外观设计保护的要求。随着经济社会... 2019年,日本外观设计法迎来大调整,特许厅希望借助此次修改带动强化产业竞争力。本次修改以保护期限扩大、保护对象扩大和对于日本独具特色的关联外观设计制度调整为主要内容,能够很好地满足信息时代外观设计保护的要求。随着经济社会的不断发展,已有越来越多的企业关注外观设计领域,而日本作为发达工业国家,其外观设计领域的立法对我国具有重要的参考价值。 展开更多
关键词 外观设计 意匠法 关联设计
在线阅读 下载PDF
DFM:“Design for Manufacturing”or“Design Friendly Manufacturing” 认领
4
作者 Wenzhan Zhoul Hung-Wen Chao +5 位作者 Yu Zhang Chan-Yuan Hu Wei Yuan Yifei Lu Hongmei Hu Xiang Peng 《微电子制造学报》 2020年第1期1-8,共8页
As the IC manufacturing enter sub 20nm tech nodes,DFM become more and more important to make sure more stable yield and lower cost.However,by introducing newly designed hardware(1980i etc.)process chemical(NTD)and Con... As the IC manufacturing enter sub 20nm tech nodes,DFM become more and more important to make sure more stable yield and lower cost.However,by introducing newly designed hardware(1980i etc.)process chemical(NTD)and Control Algorithm(Focus APC)into the mature tech nodes such as 14nm/12nm,more process window and less process variations are expected for latecomer wafer fabs(Tier-2/3 companies)who just started the competition with Tier-1 companies.With improved weapons,latecomer companies are able to review their DFM strategy one more time to see whether the benefit from hardware/process/control algorithm improvement can be shared with designers.In this paper,we use OPC simulation tools from different EDA suppliers to see the feasibility of transferring the benefits of hardware/process/control algorithm improvement to more relaxed design limitation through source mask optimization(SMO):1)Better hardware:scanner(better focus/exposure variation),CMP(intrafield topo),Mask CD variation(relaxed MEEF spec),etc.2) New process:from positive tone development to negative tone development.3)Better control schemes:holistic focus feedback,feedback/forward overlay control,high order CD uniformity improvement.Simulations show all those gains in hardware and process can be transferred into more relaxed design such as sub design rule structure process window include forbidden pitches(1D)and smaller E2E gaps(2D weak points). 展开更多
关键词 DESIGN for Manufacturing(DFM) DESIGN Friendly MANUFACTURING EUV LITHOGRAPHY Source Mask Optimization(SMO) DESIGN Technology Co-optimization(DTCO) PROCESS Window PROCESS Variation
在线阅读 免费下载
Users as co-designers:Visual-spatial experiences at Whitworth Art Gallery 认领
5
作者 Ahlam Ammar Sharif 《建筑学研究前沿:英文版》 CSCD 2020年第1期106-118,共13页
The importance of building users in the architectural field has been increasingly acknowledged in architectural research.Some studies have applied actor-network theory(ANT)to highlight the ways through which users are... The importance of building users in the architectural field has been increasingly acknowledged in architectural research.Some studies have applied actor-network theory(ANT)to highlight the ways through which users are embedded in relation to the built environment.However,many of these studies are limited in recognizing the diverse ways users manipulate these relations as they experience the same built environment differently.This study draws on a recent ANT scholarship by summarizing the ethnographic research of Whitworth Art Gallery in Manchester,United Kingdom.Findings show that users see and react to the same built environment in different ways that are not limited to their alignment or misalignment with the design.They extend to include diverse interpretations and reactions(destructing,ignoring,noticing,attending,and interacting).The different user experiences explored in this research demonstrate three main themes,namely,entanglements,continuity,and transformation,which suggest new ways of recognizing the need for increasingly adaptable and inviting designs that address different user preferences and desires. 展开更多
关键词 Actor-network theory Architectural design Design process Design technology User behavior
Reinventing the wheel:A tool for design quality evaluation in architecture 认领
6
作者 Buthayna Eilouti 《建筑学研究前沿:英文版》 CSCD 2020年第1期148-168,共21页
Addressing design evaluation as a critical yet under-researched domain,this study analyzes the design evaluation structure and its variables and criteria that guide its outcomes.Within a scope of architectural design ... Addressing design evaluation as a critical yet under-researched domain,this study analyzes the design evaluation structure and its variables and criteria that guide its outcomes.Within a scope of architectural design in practice and education,this study develops a new tool for design quality evaluation.The study consists of four main parts.The first is explorative which reviews and analyzes literature in the assessment and evaluation fields.The second is derivative and used to develop a tool for design quality evaluation(DQE)that combines design criteria and detailed evaluation rubrics.The tool which is named"Evaluation Wheel"is intended to help designers,educators and other design-related stakeholders judge design products succinctly,comprehensively,systematically and graphically.The third part is experimental and is used to test the applicability of the proposed wheel.A set of design products are evaluated by a group of designers using two methods;one uses various design criteria,and the other uses the wheel tool introduced in this research.The fourth part is analytical and evaluative which uses deductive,inductive and abductive reasoning techniques to analyze and compare the findings of the third part.The findings are presented and discussed.The results that indicate a reduction of the discrepancies of the scores among the evaluators seem to support the uptake of the proposed wheel in the design evaluation fields. 展开更多
关键词 Design evaluation tool Evaluation criteria Affective engineering Design rubrics Architectural assessment Design quality indicator Quality assurance
Design and Implementation of Lightning Analysis Software Based on Lightning Location System Data 认领
7
作者 Rong FAN Chunlong ZHANG +1 位作者 Wen'an XIAO Yaoling ZHI 《气象与环境研究:英文版》 CAS 2020年第1期21-23,共3页
This paper discusses the steps about how to design and implement software based on lightning location system data and its localization map.The system contains four major modules such as real-time lightning monitoring,... This paper discusses the steps about how to design and implement software based on lightning location system data and its localization map.The system contains four major modules such as real-time lightning monitoring,historical query,lightning intensity zoning,lightning disaster statistics,etc.The system is able to automatically generate real-time lightning monitoring image,lightning animation,and lightning intensity zoning image,which contributes to the high accuracy of the calculation results and the efficiency of data analysis.The paper also points out the deficiencies of software life cycle management and proposes actionable solutions. 展开更多
关键词 LIGHTNING location SYSTEM data(LLSD) SYSTEM DESIGN UML OBJECT-ORIENTED design(OOD) Systems development life cycle(SDLC)
在线阅读 下载PDF
人工智能“合乎伦理设计”的理论探源 认领
8
作者 闫坤如 《自然辩证法通讯》 CSSCI 北大核心 2020年第4期14-18,共5页
人工智能设计是为了满足设计主体的目的而制造人工物的过程,设计是合目的性与合价值性的统一,设计体现设计者的意愿,设计关注设计的目的、行为以及人工物的功能。与其他技术人工物不同,智能机器具有自身推理能力与自动决策功能,为了更... 人工智能设计是为了满足设计主体的目的而制造人工物的过程,设计是合目的性与合价值性的统一,设计体现设计者的意愿,设计关注设计的目的、行为以及人工物的功能。与其他技术人工物不同,智能机器具有自身推理能力与自动决策功能,为了更好地设计人工智能客体,为了充分发挥人工智能的功能,必须对其理论基础追踪溯源,对其理论来源与理论前提进行充分挖掘,才能保证人工智能设计在设计之初把人类规范与道德嵌入到智能机器中,才能规范智能机器的发展。 展开更多
关键词 人工智能 设计 合乎伦理设计 道德物化
Optimum Autofrettage Pressure of Hydrogen Valve Using Finite Element and Fatigue Analysis 认领
9
作者 Slawomir Kedziora Thanh Binh Cao 《工程(英文)(1947-3931)》 2020年第1期1-24,共24页
The presented article shows an estimation method of optimum autofrettage pressure taking into consideration subsequent cyclic loading. An autofrettage process is used in pressure vessel applications for strength impro... The presented article shows an estimation method of optimum autofrettage pressure taking into consideration subsequent cyclic loading. An autofrettage process is used in pressure vessel applications for strength improvement. The process relies on applying massive pressure that causes internal portions of the part to yield plastically, resulting in internal compressive residual stresses when pressure is released. Later applied working pressure (much lower than autofrettage pressure) creates stress reduced by the residual compressive stress improving the structural performance of the pressure vessels. The optimum autofrettage pressure is a load that maximizes the fatigue life of the structure at the working load. The estimation method of that pressure of a hydrogen valve is the subject of the presented work. Finite element and fatigue analyses were employed to investigate the presented problem. An automated model was developed to analyze the design for various autofrettage pressures. As the results of the procedure, the optimum autofrettage pressure is determined. The research has shown that the developed method can profitably investigate the complex parts giving the autofrettage load that maximizes the fatigue life. The findings suggest that the technique can be applied to a large group of products subjected to the autofrettage process. 展开更多
关键词 AUTOFRETTAGE HYDROGEN VALVE Finite Element Analysis FATIGUE Design
在线阅读 免费下载
A Computational Synthesis Approach of Mechanical Conceptual Design Based on Graph Theory and Polynomial Operation 认领
10
作者 Lin Han Geng Liu +1 位作者 Xiaohui Yang Bing Han 《中国机械工程学报:英文版》 SCIE EI CAS CSCD 2020年第1期60-74,共15页
The design synthesis is the key issue in the mechanical conceptual design to generate the design candidates that meet the design requirements.This paper devotes to propose a novel and computable synthesis approach of ... The design synthesis is the key issue in the mechanical conceptual design to generate the design candidates that meet the design requirements.This paper devotes to propose a novel and computable synthesis approach of mechanisms based on graph theory and polynomial operation.The graph framework of the synthesis approach is built firstly,and it involves:(1)the kinematic function units extracted from mechanisms;(2)the kinematic link graph that transforms the synthesis problem from mechanical domain into graph domain;(3)two graph representations,i.e.,walk representation and path representation,of design candidates;(4)a weighted matrix theorem that transforms the synthesis process into polynomial operation.Then,the formulas and algorithm to the polynomial operation are presented.Based on them,the computational flowchart to the synthesis approach is summarized.A design example is used to validate and illustrate the synthesis approach in detail.The proposed synthesis approach is not only supportive to enumerate the design candidates to the conceptual design of a mechanical system exhaustively and automatically,but also helpful to make that enumeration process computable. 展开更多
关键词 DESIGN SYNTHESIS CONCEPTUAL DESIGN GRAPH theory POLYNOMIAL operation KINEMATIC link GRAPH Weighted matrix theorem
在线阅读 免费下载
安阳县(示范区)生态走廊景观设计探究 认领
11
作者 闫玉洁 《建筑工程与管理》 2020年第2期37-40,共4页
城市景观是由多个部分共同组成,城市河道是其中之一,对于城市来说,河道是其灵魂所在。以安阳县(示范区)生态走廊景观设计为研究对象,总结了该项目在总体规划设计布局与定位、硬质景观设计、植物种植设计等三个方面的设计理念,并同类项... 城市景观是由多个部分共同组成,城市河道是其中之一,对于城市来说,河道是其灵魂所在。以安阳县(示范区)生态走廊景观设计为研究对象,总结了该项目在总体规划设计布局与定位、硬质景观设计、植物种植设计等三个方面的设计理念,并同类项目的设计实施提出了建议,以期对同类项目的科学设计和建设有所启发。 展开更多
关键词 河道景观 设计 安阳县生态走廊 布局 定位 硬质景观 植物种植设计
在线阅读 免费下载
现代机械设计的创新设计理论与方法研究 认领
12
作者 马力戈 《价值工程》 2020年第1期280-281,共2页
随着当前经济全球化的发展,现代机械制造企业的竞争就是在产品设计方面的竞争,因此要想让现代机械制造行业在未来的发展中占据市场,就需要对机械设计进行创新的理论方法。只要掌握了创新方法,机械制造行业才能够在当代的市场中掌握主导... 随着当前经济全球化的发展,现代机械制造企业的竞争就是在产品设计方面的竞争,因此要想让现代机械制造行业在未来的发展中占据市场,就需要对机械设计进行创新的理论方法。只要掌握了创新方法,机械制造行业才能够在当代的市场中掌握主导权。而且机械设计是一门复杂的科学,只有设计出创新和高效的产品,才能更好的为人民服务,为社会服务,也让机械制造公司获得相应的经济效益。本文针对现代机械设计的创新设计理论与方法研究进行分析。 展开更多
关键词 现代机械 设计 创新设计 方法
在线阅读 下载PDF
Reduction of Environmental Impact of Drum Machine Washing 认领
13
作者 Pieter Broer van der Weg (Peter) 《应用数学与应用物理(英文)》 2020年第1期132-157,共26页
An improvement of efficiency of the horizontally rotating drum washing machine is possible by using a more open type of drum, essentially without suds in the annulus, by using a pump to wet the clothes during rotation... An improvement of efficiency of the horizontally rotating drum washing machine is possible by using a more open type of drum, essentially without suds in the annulus, by using a pump to wet the clothes during rotation and fall. Modelling and simulation are used to quantify these claims and further optimize the design of the horizontal washing machine. The flow of suds inside the deforming clothes at impact with the drum is calculated. The wash performance is shown to be largely proportional to the open perforation area in the drum. The traditional design uses 1/8 of drum area for the perforation holes. A significant reduction of water, detergent, electrical energy, and wash time, with parity in wash performance, provides a step towards a cleaner and more sustainable future. 展开更多
关键词 DRUM WASH Machine Design Efficiency Poroelastics DARCY Simulation MODELLING
在线阅读 免费下载
Design of a Centrifugal Compressor with Low Solidity Vaned Diffuser(LSVD) for Large-Scale Compressed Air Energy Storage(CAES) 认领
14
作者 LIANG Qi ZUO Zhitao +2 位作者 ZHOU Xin TANG Hongtao CHEN Haisheng 《热科学学报:英文版》 SCIE EI CAS CSCD 2020年第2期423-434,共12页
Compressed Air Energy Storage(CAES) has tremendous promotional value in the intermittent renewable energy supply systems. CAES has special requirements for compressor(e.g. heavy load, high pressure ratio, wide range).... Compressed Air Energy Storage(CAES) has tremendous promotional value in the intermittent renewable energy supply systems. CAES has special requirements for compressor(e.g. heavy load, high pressure ratio, wide range). With advantages of higher efficiency and wider operation range, IGC(Integrally Geared Compressors) is selected to fulfill the special requirements of the large-scale CAES. To get a better aerodynamic performance, in this paper, based on the analysis of internal flow of centrifugal compressor, a multi-objective one-dimensional optimization design program was put forward combined with modified Two-Zone model and a low solidity vaned diffuser(LSVD) design method. Then, a centrifugal compressor aerodynamic component optimization design system was established with the three-dimensional blade optimization design method based on neural network and genetic optimization algorithm. Then a validation was done by redesigning the Krain-Impeller to get better performance. Finally, the aerodynamic design of the first stage of IGC was completed. The CFD calculation results indicated that the total-to-total pressure ratio of the first stage was 2.51 and the polytropic efficiency was 91.0% at the design point. What’s more, an operation margin and surge margin of the compressor was about 26.5% and 16.4% respectively. 展开更多
关键词 compressed air energy storage(CAES) centrifugal compressor aerodynamic DESIGN LOW SOLIDITY vaned diffuser(LSVD) Two-Zone model blade DESIGN
Disassembly Evaluation in Design of a System Using a Multi-Parameters Index 认领
15
作者 Aslain Brisco Ngnassi Djami Wolfgang Nzié Serge Doka Yamigno 《现代机械工程(英文)》 2020年第1期1-16,共16页
In order to help designers, consider disassembly in their design activities, a method for evaluation of product disassembly is proposed. Criteria characterizing the disassembility of a product are identified. Each cri... In order to help designers, consider disassembly in their design activities, a method for evaluation of product disassembly is proposed. Criteria characterizing the disassembility of a product are identified. Each criterion is assigned a coefficient, thus proposing an index of easy fixations (Iff) as a design indicator to evaluate the level of disassembly of a solution generated by the designer. This index is calculated as a weighted average of the indicators for evaluating the disassembility of the product. The proposed method uses information such as the list of subsets or parts, the component tree, the part geometry, the functional links between components and parts, the properties of the components. It has been tested on one product: the soy roaster. 展开更多
关键词 DESIGN DISASSEMBLY CRITERIA EVALUATION INDICATORS
在线阅读 免费下载
蜕变--科技革命下的设计走向分析 认领
16
作者 蒋泽云 陈聪 《设计》 2020年第4期96-98,共3页
本文将运用案例分析法来探索在科技革命影响下设计的发展现状、以及新时代背景下设计的未来走向。在以服务设计为主的分析中,可以看出在科技革命的大背景下及其新科学技术、新社会需求下,设计的发展、知识体系、设计方式、设计思维模式... 本文将运用案例分析法来探索在科技革命影响下设计的发展现状、以及新时代背景下设计的未来走向。在以服务设计为主的分析中,可以看出在科技革命的大背景下及其新科学技术、新社会需求下,设计的发展、知识体系、设计方式、设计思维模式、设计教育、设计服务和设计责任均发生了转变。当下是设计发展的蜕变时期,未来的设计在知识、方式、思维模式、教育、服务这方面将是更具思维性的、多视域的、未来性的、探索性的和生态系统性的,并且将承担起更多的社会责任和道德。 展开更多
关键词 设计 科技 蜕变 思维 服务设计
在线阅读 下载PDF
Synthetic of Some New Fluorine Compounds Bearing 1,2,4-Triazine Moieties and the Related Hetero-Polycyclic Nitrogen Systems as Pharmacological Probes-Overview 认领
17
作者 Dina A. Bakhotmah Fatimah A. Alotaibi 《有机化学国际期刊(英文)》 2020年第1期17-38,共22页
This overview summarizes recent advanced literature surveys on the synthesis of fluorine substituted 1,2,4-triazine containing various functional groups and/or the related hetero-polycyclic nitrogen systems have been ... This overview summarizes recent advanced literature surveys on the synthesis of fluorine substituted 1,2,4-triazine containing various functional groups and/or the related hetero-polycyclic nitrogen systems have been reported. In addition, physical, chemical, and medicinal properties have been evaluated. The presence of fluorinated atoms often improves these properties with an increasing electronegativity. It, also, enhances the stability of formed carbanion and it improves the hydrophobic effects which have good biological activities. 展开更多
关键词 Design Synthesis FLUORINATED 1 2 4-Triazino/1 4-Triazinone MEDICINAL Properties
在线阅读 免费下载
浅析牛仔服装的再设计 认领
18
作者 包令晖 《工业设计》 2020年第1期69-70,共2页
随着经济的快速增长,服装潮流的迅速更跌,服装不断推陈出新。消费者对流行款式服装的盲目追求,导致大量服装浪费。尤其是时尚的牛仔服装,齐全的款式,适中的价格,使得大量不流行的牛仔服装被淘汰。这些被弃置的牛仔服装完全可以通过再设... 随着经济的快速增长,服装潮流的迅速更跌,服装不断推陈出新。消费者对流行款式服装的盲目追求,导致大量服装浪费。尤其是时尚的牛仔服装,齐全的款式,适中的价格,使得大量不流行的牛仔服装被淘汰。这些被弃置的牛仔服装完全可以通过再设计手段重新拥有审美价值,走进流行行列。本文通过阐述牛仔服装再设计的意义及牛仔服装再设计的方法,希望对当代牛仔服装设计的发展提供一定的借鉴,同时对环境的保护做出一份力量。 展开更多
关键词 牛仔服装 再设计 意义 设计方法
在线阅读 下载PDF
关于农村公路设计思路的探讨 认领
19
作者 刘宝伟 《智能城市应用》 2020年第1期87-89,共3页
农村公路是支撑农业和农村经济社会发展的重要基础设施,2019年以来,全国新改建农村公路29万公里,提前实现具备条件的乡镇和建制村通硬化路。笔者亲历了十多年来农村公路发展的全过程,参与近千个农村公路项目设计,现结合近年来的农村公... 农村公路是支撑农业和农村经济社会发展的重要基础设施,2019年以来,全国新改建农村公路29万公里,提前实现具备条件的乡镇和建制村通硬化路。笔者亲历了十多年来农村公路发展的全过程,参与近千个农村公路项目设计,现结合近年来的农村公路新建、改建设计经验,就农村公路设计思路谈一下自己的看法。 展开更多
关键词 农村公路 设计 设计原则
在线阅读 免费下载
论如何通过色彩增加设计中的互动性 认领
20
作者 李安娜 《设计》 2020年第9期94-96,共3页
探讨设计师如何利用色彩增加设计的互动性。采用分析法,以色彩的基本理论为出发点,结合人们对色彩的感知和情感积累进行理论分析。运用归纳法和综合法总结人们对色彩的视觉反应和心理体验,以举例的方式讨论设计师如何通过色彩与受众进... 探讨设计师如何利用色彩增加设计的互动性。采用分析法,以色彩的基本理论为出发点,结合人们对色彩的感知和情感积累进行理论分析。运用归纳法和综合法总结人们对色彩的视觉反应和心理体验,以举例的方式讨论设计师如何通过色彩与受众进行沟通和互动,以及色彩应用方法和注意事项。在设计中利用色彩色调、对比、象征或者色彩组合等均可增加作品中的互动性。该探讨能够为从事设计工作和研究的人员提供参考价值和创作灵感。 展开更多
关键词 设计 色彩 设计互动
在线阅读 下载PDF
上一页 1 2 250 下一页 到第
使用帮助 返回顶部 意见反馈