走出选卡迷魂阵 显卡选购的五大误区曝光

不管是什么商品,在选购过程中都有各种各样的误区,尤其在技术含量较高的DIY配件里面,不同厂家、不同芯片、不同型号、不同规格的产品总让人眼花缭乱,加上各种夸张手法的广告,买家只要稍有不慎就会购买到高价低能或者低质的产品,今天我们就来看看在购买DIY配件中的显卡部件,一般用户在选购过程中最容易犯的错误。     

Kinetics of the Benzylation of Potato Starch

The formation of benzyl ethers of potato starch by etherification with benzyl chloride is base catalyzed and is therefore carried out at high pH. In a suspension of starch granules the rate of starch ether formation is found not to be linearly related to the concentration of hydroxyl ions in the water phase of the suspension. At the same pH widely different rates of reaction can be observed, to be due to the tendency of the starch granules to “absorb” hydroxyl ions when electrolytes are added to the suspension. The rate of formation of the benzyl ether of starch is found to be linearly related to the amount of hydroxyl ions “absorbed” by the starch. The rate of the side reaction leading to benzyl alcohol turned out to be higher in the presence of starch than in water of the same pH.     

The electrochemical recovery of metallic palladium from spent electroless plating solution

Semiconductor bond pads are sometimes coated with palladium for good electrical properties and wire adhesion. The palladium is deposited by immersing the wafers in an electroless plating solution. When the plating solution is depleted and no longer achieves the desired results it is treated as waste. This work investigates the recovery of the remaining palladium in the waste solution by means of electrochemical deposition onto a high surface area cathode. Experiments show that the remaining palladium can be recovered economically and efficiently. This makes the process environmentally friendly and cost effective.     

Warm homes: Drivers of the demand for heating in the residential sector in New Zealand

New Zealand houses are large, often poorly constructed and heated, by OECD standards, and consequently are colder and damper indoors than recommended by the World Health Organisation. This affects both the energy consumption and the health of households. The traditional New Zealand household pattern of only heating one room of the house has been unchanged for decades, although there has been substantial market penetration of unflued gas heaters and more recently heat pumps. This paper describes the residential sector and the results of two community-based trials of housing and heating interventions that have been designed to measure the impact of (1) retrofitting insulation and (2) replacing unflued gas heaters and electric resistance heaters with heat pumps, wood pellet burners and flued gas heaters. The paper describes findings on the rebound effect or ‘take-back’—the extent to which households take the gains from insulation and heating improvements as comfort (higher temperatures) rather than energy savings, and compares energy-saving patterns with those suggested by an earlier study. Findings on these aspects of household space heating are discussed in the context of the New Zealand government's policy drive for a more sustainable energy system, and the implications for climate change policy.     

A method for the prediction of microwave properties of thick film conductors from physical measurements and d.c. conductivity

It is theoretically possible to calculate electrical losses in conductors at high frequencies using standard microstrip equations. To do this it is necessary to know the length, width and surface roughness of sample tracks. The sheet resistance at d.c. is replaced with a new term, surface resistance which is the bulk resistivity divided by the skin depth at the frequency under consideration. The paper looks at the relationship between these predictions and measured results. A wide range of commercial thick film conductors has had its physical properties measured and a comparison made with the figures for idealized structures. The paper contains a discussion on the differences between real and ideal materials. It was seen that the predictions were close to the measured results at lower frequencies, but that there was divergence as the frequency approached 15–20 GHz. For low-cost applications it is generally considered that economically viable conductors will be unsuitable for microwave applications. However, the paper discusses whether some of the lesser used conductors, such as fritted silver, could have an application in low-cost microwave devices, for example alarm systems. © 2001 Kluwer Academic Publishers     

Three-port ring discriminator

A novel microwave discriminator is described which uses a single microstrip three-port ring. Results are presented for a representative circuit which show good agreement between theoretical and experimental results over a 20% bandwidth centred on 10 GHz. The device exhibits a narrowband match with a VSWR of 1.14 at the centre (design) frequency.     

瑞典创世纪的6大品牌

瑞典虽然只有960万人口．却诞生了许多知名的跨国公司，人们熟悉的爱立信、沃尔沃、绅宝、山德维克、宜家和伊莱克斯等都诞生于北欧的这片土地上。而从小在工业设计环境熏陶中长大的瑞典人．则在总部牢牢地把握着设计工作。这是谁也抢不走．且源源不断从头脑中诞生的财富。连瑞典人自己也很难说清楚．瑞典到底有多少工业设计师．本文就带大家进入瑞典．看看你可能会惊讶很多非常熟悉的品牌．居然都出自只有中国黑龙江面积那么大的瑞典。     

A new corrosion inhibition model for surfactants that more closely accounts for actual adsorption than traditional models that assume physical coverage is proportional to inhibition

Many corrosion inhibition researchers utilize the assumption that inhibitor coverage is proportional to corrosion inhibition as a tool to evaluate their inhibition data. Although this assumption is very useful, it is inconsistent with observed surfactant adsorption data. Corrosion and adsorption data indicate that corrosion inhibition by surfactants is not directly proportional to surfactant coverage. This paper discusses the discrepancy between physical and effective coverage and provides an alternative relationship between coverage and inhibition that is more consistent with observed surfactant adsorption than the traditional relationship, which for most researchers means that physical coverage is proportional to corrosion inhibition.     

Low cost microwave thick film structures

This paper examines the potential use of low cost materials and processes to produce thick film structures at low microwave frequencies. It examines empirically the upper frequency limits for the use of simple design techniques as a function of substrate thickness. It concludes that satisfactory results can be obtained using low cost methods up to about 12 GHz for 1 mm 96% alumina substrates and 16 GHz for 0.63 mm substrates. These are the most commonly available thick film substrate thicknesses. A low permittivity protective layer is desirable to maintain reliability.