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241.
Epoxy adhesives filled with four different volume fractions of eutectic tin-bismuth solder alloy were prepared and the effect of filler content on the electrical and mechanical properties of these anisotropic electrically conductive adhesives was investigated. The results show that the adhesive containing the lowest amount of the filler alloy had the best combination of conductivity, insulation resistance and shear strength. The DSC-measurements suggested that the filler melts before the cure of the resin begins which allows the filler to wet and bond well to the conductors. This was verified by SEM/EPMA examinations. A temperature cycling test and high humidity, high temperature treatment were conducted on the best composite adhesive. The temperature variation had no effect on conductivity of the joints while humid and hot environment decreased the conductivity. 相似文献
242.
中浓度气力输送弯管压力降数值模拟研究 总被引:2,自引:0,他引:2
对于中等浓度气力输送90°弯管内的气固流动状态进行数值模拟研究,并对水平转垂直、垂直转水平,不同弯径比(R/D=1.5~6.0)的90°弯管,均匀和非均匀粉体颗粒流过弯管的压力降Δp进行了模拟计算。结果表明,在同一气体流速下,不同R/D的弯管的Δp变化显著;存在一个使Δp最小的R/D值。在模拟的条件范围内,弯管内粉体颗粒的速度分布随R/D变化。并讨论了不同R/D的粉体颗粒流动对弯管压力降及管壁磨损的影响。在同样操作条件下,对煤粉输送进行了弯管压力降数据模拟,其模拟计算结果与周建刚等人的试验结果吻合良好。 相似文献
243.
Woon Wong 《时间序列分析杂志》1997,18(2):181-194
A stationary multivariate time series { X t } is defined as linear if it can be written in the form X t = ∑∞ j =−∞ A j e t − j where A j are square matrices and e t are independent and identically distributed random vectors. If the e t } are normally distributed, then { X t is a multivariate Gaussian linear process. This paper is concerned with the testing of departures of a vector stationary process from multivariate Gaussianity and linearity using the bispectral approach. First the definition and properties of cumulants of random matrices are used to obtain the expressions for the higher-order cumulant and spectral vectors of a linear vector process as defined above. Then it is shown that linearity of a vector process implies constancy of the modulus square of its normalized higher-order spectra whereas the component of such a vector process does not necessarily have a linear representation. Finally, statistics for the testing of multivariate Gaussianity and linearity are proposed. 相似文献
244.
针对我国化肥生产企业质检机构的现状 ,结合国家相关政策的要求 ,就如何搞好化肥企业质检机构的管理提出了诸多指导性意见 相似文献
245.
Gquest: Modeling patient questionnaires and administering them through a mobile platform application
Background
The use of surveys is becoming popular in the health care industry for acquiring information useful to the accomplishment of several studies. Besides their exploitation on a large scale for conducting epidemiological studies, surveys are being increasingly carried out on a narrower perspective through the administration of questionnaires aimed at assessing the quality of life perceived by patients or their clinical status during mid- or long-term treatments. This is useful for managing resources or optimizing and individualizing treatments.Objectives
This paper describes Gquest, a platform for modeling, generating and administering questionnaires through mobile devices such as smartphones or tablets. Gquest was motivated by the need of administering questionnaires during home treatments, albeit its applicability is rather general. The main requirement was to have a very simple, clean and easy to use platform able to support (a) physicians in the design and delivery of questionnaires and (b) outpatients in sending self-recorded outcomes to the clinical staff.Methods
Gquest has two basic components. The first one is a model devised for representing questionnaires which is extremely flexible. It allows the generation of questions and answers of different types, supports adaptivity in the dialog with the user and enforces simple consistency rules for checking his input. The second component is an application able to run instances of those questionnaires. It downloads questionnaires over the air in terms of XML files from a server and stores them locally into the mobile repository. Questionnaires become then available to the user, who in our case is a patient or one of his relatives. The user can select which one to fill-in, according to his needs and/or the specific treatment protocol. The selected questionnaire may be filled-in all at once or be completed in subsequent steps over time since any input provided is persisted on a local database. Finally, when a questionnaire is closed all the answers are transparently synchronized to a server for further evaluation or statistical purposes.Results
The platform has been exploited and tested in two medical domains where questionnaires have very different purposes; a quality of life pilot survey involving patients with atrial fibrillation within the EU-funded project MobiGuide, and an investigation of the users’ needs during the requirements elicitation phase of a telemedicine project for the safe discharge of fragile patients.Conclusions
Gquest proved to be a suitable tool for dealing with a wide variety of question types and has been positively accepted by the patients enrolled in the pilot study. 相似文献246.
列车用CAN总线协议一致性测试是保证不同设备制造厂家生产的CAN通信设备之间实现互联、互通和互操作的前提。在对协议一致性测试原理和CAN总线协议特点进行简要分析的基础上,提出了针对CAN总线协议一致性测试的协同测试方法和相应的一致性测试内容,设计并构建了相应的一致性测试硬件平台,并对测试软件平台中可执行测试实例产生、测试执行、测试评估以及测试管理等诸多环节所涉及的基本功能软件进行了设计和实现,完成了CAN协议一致性测试的基本功能。实际运行和测试结果表明:所设计的测试平台达到了预期结果,为下一步列车用CAN总线协议的一致性测试打下了基础。 相似文献
247.
248.
249.
M. D. A. Bolland 《Nutrient Cycling in Agroecosystems》1993,35(1-2):83-91
The relationship between plant yield and values of soils tests for phosphorus (P) was studied in long-term field experiments
in south-western Australia for soil previously fertilized with rock phosphate and superphosphate. The rock phosphates studied
were: Queensland (Duchess) apatite rock phosphate; reactive apatite rock phosphate from North Carolina; and rock phosphate
from Christmas Island (as either C-grade ore or Calciphos). The P fertilizers were applied once only at the start of each
experiment, and in subsequent years, soil samples were collected in January-March to measure soil test values. These were
compared with plant yields measured later on in that year. The Colwell alkaline bicarbonate soil test was used in all years
in all experiments. Olsen, Bray, lactate and Troug tests were used in some years in some experiments.
For all soil tests the relationships between yield and soil test values was generally different for rock phosphate and superphosphate.
For a given source of P, none of the different soil test reagents was significantly superior for predicting plant yields.
The relationship between yield and soil test value was also generally different for different plant species. At one site cultivation
was included as a treatment and the relationship varied depending on the cultivation treatment of the topsoil before sowing
oats (Avena sativa). The relationship between yield and soil test also differed between years. 相似文献
250.
激励信号频率是影响高频电容式土壤水分传感器性能的重要因素。利用去离子水和2—异丙氧基乙醇(2—isoproxyethanol)或二氧六环(dioxane)2种溶液混合,配制了一系列等效土壤体积含水率为0.9%~51.8%的待测介电溶液来替代土样。从与土壤含水率的函数关系、温度变异性2个方面,分别对激励信号频率为40,50,60,70,80,90,100 MHz的7种土壤水分传感器进行了性能测试与分析。结果表明:7种频率的传感器的输出电压均与土壤体积含水率呈线性负相关,其相关系数R2均大于0.94;激励信号频率不影响传感器输出电压的温度变异性,温差是影响温度变异性的主要因素,其最大变异率均小于4%。试验结果可为设计高频电容式土壤水分传感器时选择激励信号频率提供依据。 相似文献