无线传感器网络中OOFSK与FSK传输方法的综合能效性能对比研究

无线传感器网络(WSNs)是信息科学领域中一个全新的发展方向,且已经得到广泛的应用。无线传感器网络的传输体制很大程度上决定了整个无线传感器网络的数据传输可靠性和电池供电条件下的能效性能。另一方面,频移键控(FSK)和开关频移键控(OOFSK)是无线传感器网络中重要的传输方式;因此,本文提出了一种无线传感器网络节点在电池供电条件下,分析比较FSK和OOFSK误码率性能和电池能效的方法,并推导了FSK和OOFSK这两种传输体制下误码率和电池能效的综合性能对比关系。从数值分析结果可知OOFSK调制在一定的信噪比条件下,其误码率性能优于FSK调制,且综合能效性能改善随着OOFSK调制的占空比v的减小而有显著的提高。此外,OOFSK调制占空比v对综合能效性能的影响明显超过信噪比的影响。

不同透过率下非晶硅光伏窗综合能效性能研究

利用EnergyPlus建立通风型非晶硅光伏窗传热、采光、发电的综合模型,研究不同透过率下非晶硅光伏窗的热光电性能。使用实验数据验证所建模型的准确性,并用验证的模型分别研究不同气候区非晶硅光伏窗透过率对发电量、室内照明能耗、空调能耗、综合能耗的影响。结果表明:适宜透过率的光伏窗产生的电量能对建筑空调采光能耗进行补偿,使整体能耗最少。广州、昆明、长沙、北京、哈尔滨5个城市综合能耗最少时的最佳透过率分别为0.22~0.25、0.25、0.25~0.30、0.25~0.30、0.35。

磁耦合无线电能传输系统能效性能在线监测器设计

无线电能传输(WPT,wireless power transfer)技术目前已被应用到生产生活的很多领域,在WPT系统运行和调试时,需要对系统进行监测以了解系统的实际工作状况。给出了一种上位机与下位机结合的无线电能传输系统能效性能监测器设计方案,以LCC-S型磁耦合WPT系统为监测对象,对监测系统需求进行了分析,给出了WPT系统各能效性能参数的计算公式,提出基于STM32的下位机和基于PC与LabVIEW的上位机系统硬件和软件设计方法。最后通过实验验证了所提出的无线电能传输系统能效性能在线监测器设计方案和设计方法的合理性和可行性。

电动机效率对容积式空压机的能效及节能性能的影响

本文以分别采用普通电动机和高效电动机的同一台空压机为研究对象,分别探讨了采用普通电动机和高效电动机对试样能效及节能性能的影响。结果标明:当采用高效节能电动机时,机组输入比功率测试结果小于节能评价值,整机为节能空压机;采用普通电动机时,机组输入比功率测试结果大于节能评价值,整机为非节能空压机。因此,选用电动机的效率对空压机的节能性能起到了关键的作用。

通风空调的噪声控制技术研究

通风空调系统作为调控室内环境的主要设备,其运行带来的噪声成为了影响室内声环境的主要来源之一。本研究针对通风空调系统中的噪声控制技术进行深入探讨。首先,通过对通风空调系统的运行机理进行分析,挖掘生成噪声的可能源头。然后,根据噪声的传播规律,采取有效的隔声、消声,积极性和被动性的噪声控制技术进行处理。同时引入了数值模拟技术,对不同控制策略的噪声控制效果进行评估,以指导实践应用。研究结果表明,采取合理的噪声控制措施,不仅能有效降低通风空调系统的噪声,还能提高系统的能效性能。这为提升室内舒适度,改善生活品质提供了实用性的技术手段。

英国征求能效最低标准

2009年12月18日．据DERRA网站消息，英国环境、食品及农村事务部（Defra）今日宣布对一系列产品的最低能效标准拟议开展评议。

Evolution of mechanical properties,localized corrosion resistance and microstructure of a high purity Al-Zn-Mg-Cu alloy during non-isothermal aging

The evolution of mechanical properties,localized corrosion resistance of a high purity Al-Zn-Mg-Cu alloy during non-isothermal aging(NIA)was investigated by hardness test,electrical conductivity test,tensile test,intergranular corrosion test,exfoliation corrosion test,slow strain rate tensile test and electrochemical test,and the mechanism has been discussed based on microstructure examination by optical microscopy,electron back scattered diffraction,scanning electron microscopy and scanning transmission electron microscopy.The NIA treatment includes a heating stage from 40℃to 180℃with a rate of 20℃/h and a cooling stage from 180℃to 40℃with a rate of 10℃/h.The results show that the hardness and strength increase rapidly during the heating stage of NIA since the increasing temperature favors the nucleation and the growth of strengthening precipitates and promotes the transformation of Guinier-Preston(GPI)zones toη'phase.During the cooling stage,the sizes ofη'phase increase with a little change in the number density,leading to a further slight increase of the hardness and strength.As NIA proceeds,the corroded morphology in the alloy changes from a layering feature to a wavy feature,the maximum corrosion depth decreases,and the reason has been analyzed based on the microstructural and microchemical feature of precipitates at grain boundaries and subgrain boundaries.

6G网络架构研究进展及建议

6G网络架构的研究包括组网生态、面向高性能和能效的软硬件联合设计通信架构、云原生/算力网络和服务架构、新能力(可信安全内生和智能内生)架构4个维度。这4个维度与ITU-R IMT-2030(6G)框架文件中的场景和指导原则密切相关。对中国、欧盟、美国三方的主要研究进展分别做了介绍和对比分析,并给出了一些关于中国6G网络架构研究的建议。

民用建筑电气设计中的节能措施

目前,随着人们对生活物质水平要求的不断提高,以及对绿色生活的提倡,建筑行业越发重视民用建筑的节能功能。在民用建筑应用方面,电气设计是其中较为重要的环节,应用节能措施可以大幅降低民用建筑的能源消耗。对此,本文旨在探讨民用建筑电气设计中的节能措施,包括照明系统、空调系统、供电系统等方面的综合应用,通过合理的设计和技术手段,可以有效降低能源消耗,提高建筑的能效性能,实现可持续发展。

Experimental study and energy saving analysis of a novel radiant ceiling heating system

In order to have an in-depth understanding of the metal ceiling radiant panel with capillary tubes, a radiant ceiling heating system is constructed to study the actual heating performance and thermal comfort by experiments. In addition, the energy saving potential of the novel heating system is discussed in terms of the COP （coefficient of performance） of the ground source heat pump and the exergy efficiency of the radiant terminal. The results indicate that the heating system shows high thermal stability and thermal comfort. When the system reaches a stable condition, the radiant heat transfer accounts for 62.7% of the total heat transfer, and the total heat transfer can meet the heating demands of most buildings. Compared to a radiant floor heating system, it offers advantages in a shorter preheating time, a lower supply water temperature and a stronger heating capability. The COP of the ground source heat pump is increased greatly when the supply water temperature is 28 to 33 ℃, and the exergy efficiency of the metal ceiling with capillary tubes is 1.6 times that of the radiant floor when the reference temperature is 5 ℃ The novel radiant ceiling heating system shows a tremendous energy saving potential.

电饭煲产品质量状况分析报告

电饭煲作为传统厨房电器品类,已经成为家庭必备的一种家用电器。但是,近几年市场监督抽查发现多批次的电饭煲产品存在质量风险,本文通过汇总市场监督抽查情况、产品召回案例,分析不合格原因,给消费者提出了选购建议。

Multistage-aging process effect on formation of GP zones and mechanical properties in Al-Zn-Mg-Cu alloy

The tensile properties and fatigue behavior of an Al-Zn-Mg-Cu alloy were investigated by performing tensile tests and fatigue crack propagation （FCP） tests. The tensile results show that lower aging temperature modified retrogression and re-aging （RRA） process enhances the elongation, but reduces the strength of the alloy, as compared to conventional RRA process which employs peak aging temperature. Both ductility and strength, however, are increased by employing a natural aging prior to re-aging based on the former modified RRA process. Fatigue test results show that both routes reduce FCP rate. Especially, the lower re-aging temperature modified RRA process obtains the lowest FCP rate. Natural aging treatment could enhance the nucleation rate of GP zones. A large amount of GP zones could be cut by dislocations, which is responsible for the highest tensile strength and elongation, as well as lower FCP rate.

Size effects on deformation behavior of C5210 phosphor bronze thin sheet

To investigate the effects of thickness and grain size on mechanical and deformation properties of C5210 phosphor bronze thin sheets, samples with different grain sizes were obtained through annealing heat treatment at different temperatures; and then tensile tests of samples with different thicknesses and grain sizes were conducted at room temperature. The results show that yield strength increases with decreasing thickness from 800 to 50 μm, but work hardening exponent and total elongation decrease, and a modified model was proposed to describe the relation between yield strength and thickness; yield strength decreases as the grain size increases, but work hardening exponent shows an increasing trend, total elongation increases to a peak and then decreases. Fracture morphology of tensile specimens was observed by SEM, which indicates that all tensile specimens are ductile fracture. The dimple intensity increases as the specimen thickness increases but reduces with the specimen grain size increasing.

Influence of bismuth on microstructure,thermal properties,mechanical performance,and interfacial behavior of SAC305−xBiCu solder joints

This research sought to improve the properties of SAC305 solder joints by the addition of 1 and 2 wt.%Bi.The effects of bismuth doping on the microstructure,thermal properties,and mechanical performance of the SAC305−xBiCu solder joints were investigated.Bi-doping modified the microstructure of the solder joints by refining the primaryβ-Sn and eutectic phases.Bi-doping below 2 wt.%dissolved in theβ-Sn matrix and formed a solid solution,whereas Bi additions equal to or greater than 2 wt.%formed Bi precipitates in theβ-Sn matrix.Solid solution strengthening and precipitation strengthening mechanisms in theβ-Sn matrix increased the ultimate tensile strength and microhardness of the alloy from 35.7 MPa and 12.6 HV to 55.3 MPa and 20.8 HV,respectively,but elongation decreased from 24.6%to 16.1%.The fracture surface of a solder joint containing 2 wt.%Bi was typical of a brittle failure rather than a ductile failure.The interfacial layer of all solder joints comprised two parallel IMC layers:a layer of Cu6Sn5 and a layer of Cu3Sn.The interfacial layer was thinner and the shear strength was greater in SAC305−xBiCu joints than in SAC305Cu solder joints.Therefore,small addition of Bi refined microstructure,reduced melting temperature and improved the mechanical performance of SAC305Cu solder joints.

Energy Performance and Condensation Risk of DCDV System in Subtropical Hong Kong

The combined use of dry cooling(DC) system and dedicated ventilation(DV) system to decouple cooling and dehumidification process for energy efficiency was proposed for subtropical climates like Hong Kong. In this study, the energy performance and condensation risk of the use of DCDV system were examined by analyzing its application in a typical office building in Hong Kong. Through hour-by-hour simulation using actual equipment performance data and realistic building and system characteristics, it was found that with the use of DCDV system, the annual energy consumption could be reduced by 54% in comparison with the conventional system(constant air volume with reheat system). In respect of condensation risk, it was found that the annual frequency of occurrence of condensation on DC coil was 35 h. Additional simulations were conducted to examine the influence of different parameters on the condensation risk of DCDV system. Measures to ensure condensate-free on DC coil were also discussed.

Daylighting Strategies： Building＇s Sustainability and Energy Efficiency

Improving daylighting strategy is a mandatory step to achieve visual enjoyment and energy saving in buildings. Psycho, physiological effects and energy performance have to be investigated in order to define a range of different daylighting strategies, thanks to daylighting devices and climate based daylight modeling. Daylighting optimization ensures indoor healthier rooms, reduces electric light consumption and cuts the risk of glare. The best way to achieve these targets is to define users lighting needs, based on visual targets and to draw up some green measures to reduce electricity demands. Involving new climate-based daylight modeling metrics aims at defining proper illumination targets, in order to drastically reduce electrical lights, as well as reducing thermal loads deriving from cooling and HVAC （heating, ventilation and air conditioning） systems.

Experimental investigation of effect of refrigerant gases,compressor lubricant and operating conditions on performance of a heat pump

In the field of heat pumps,there are a number of parameters that affect the performance and efficiency of the apparatus,which have been the subject of studies by individual researchers in the literature.This study describes an experimental method in order to investigate the effects of some significant parameters on heat pump performance.In this regard,a laboratory heat pump setup has been utilized to operate in different working conditions for achieving an appropriate estimation to find out effects of mentioned parameters such as refrigerant type and charge amount,compressor oil viscosity,compressor cooling fan,secondary fluids temperature and flow rate.Different refrigerants have been selected and used as circulating fluid in the installed heat pump.Although this work has been devoted to a detailed attempt to recognize the effects of various parameters on the coefficient of performance(COP) value,an appropriate method has been carried out to survey the obtained results by using economic analysis.It was revealed that one of the main parameters is refrigerant charge amount which has a notable effect on COP.The temperature of the heat source was also tested and the performance of the system increased by more than 11% by employing mentioned modifications and various operating conditions.In addition,by selecting a low viscosity compressor oil,the system performance increased by 18%.This improvement is more than 6% for the case that cooling fan is installed to cool the compressor element.

BENIMPACT Suite： A Tool for ZEB Performance Assessment

In the last years, there has been a big development of European policies and regulations on energy saving topics. This is due to the will to reach the targets of 20-20-20. Buildings consume a lot of energy, so the legal framework related to the reduction of energy consumption in this sector has had a huge evolution. The ＂NZEB （nearly zero energy building）＂ concept was introduced in 2010, eight years after the release of the original EPBD （energy performance of buildings directive）. By 2020, all new buildings and buildings that are subject to renovation should have very low energy consumption, covered for the major part by renewable sources. Designing and realizing this kind of building is a very ambitious task, which needs to be supported by appropriate tools and software. This paper presents a new tool for assessing building performance, named BENIMPACT Suite （building＇s environmental impact evaluator and optimizer）, which is developed by EnginSoft （Italy）. The suite is organized in different core modules that allow to verify how the building performance level is influenced by different design choices, such as envelope shape and materials, plant systems, renewable sources use, etc.. One of the test cases used to validate the BENIMPACT Suite energy performance is the evaluation of an interesting Italian ZEB, finished in 2010 and called CasaZeroEnergy. It is located in Felettano （Udine）, a small town in northeastern Italy. This building is an experimental house designed and monitored by the Laboratory of Building Design of the University of Trento （Italy） and built by Polo Le Ville Plus Group （Cassacco-ltaly）. The energy performance of this building was modelled and evaluated using BENIMPACT Suite, and simulation results were compared with monitored data.

Differential Capillary Effect Model of Fabric and Its Application

The concept of the differential capillary effect was presented by foreign scholars several years ago, and the principle was used to design sportswear fabrics with good wet permeability and good drying functions for famous sports teams. Because the differential capillary effect model was not established in theory,it was impossible to fulfill the best functions. In this paper, by setting up the differential capillary effect of fabric, the factors to influence wet permeability and drying functions of the model is discussed in theory, and the means to optimize the design of the fabric is presented and proven practically by the experiment. The optimum fabric with good permeability and good drying functions can be designed using the model at last.

我国节能灯产业现状及检测过程中典型问题探讨

首先简要介绍了我国电子节能灯的产业现状,然后针对在节能灯检测过程中碰到一些突出的典型问题,结合各级别抽查,对有关问题做了简单明了的分析,并提出明确的改进建议。