YW1硬质合金热电性能的研究

本文对ＹＷ１硬质合金的热电性能进行了全面的实验研究，对影响ＹＷ１硬质合金的热电性能微观组织进行了细致的实验测试，从而找出了影响ＹＷ１硬质合金热电性能的关键因素。     

The Practical Significance of Measurement Error in Pulmonary Function Testing Conducted in Research Settings

Conventional spirometry produces measurement error by using repeatability criteria (RC) to discard acceptable data and terminating tests early when RC are met. These practices also implicitly assume that there is no variation across maneuvers within each test. This has implications for air pollution regulations that rely on pulmonary function tests to determine adverse effects or set standards. We perform a Monte Carlo simulation of 20,902 tests of forced expiratory volume in 1 second (FEV₁), each with eight maneuvers, for an individual with empirically obtained, plausibly normal pulmonary function. Default coefficients of variation for inter‐ and intratest variability (3% and 6%, respectively) are employed. Measurement error is defined as the difference between results from the conventional protocol and an unconstrained, eight‐maneuver alternative. In the default model, average measurement error is shown to be ～5%. The minimum difference necessary for statistical significance at p < 0.05 for a before/after comparison is shown to be 16%. Meanwhile, the U.S. Environmental Protection Agency has deemed single‐digit percentage decrements in FEV₁ sufficient to justify more stringent national ambient air quality standards. Sensitivity analysis reveals that results are insensitive to intertest variability but highly sensitive to intratest variability. Halving the latter to 3% reduces measurement error by 55%. Increasing it to 9% or 12% increases measurement error by 65% or 125%, respectively. Within‐day FEV₁ differences ≤5% among normal subjects are believed to be clinically insignificant. Therefore, many differences reported as statistically significant are likely to be artifactual. Reliable data are needed to estimate intratest variability for the general population, subpopulations of interest, and research samples. Sensitive subpopulations (e.g., chronic obstructive pulmonary disease or COPD patients, asthmatics, children) are likely to have higher intratest variability, making it more difficult to derive valid statistical inferences about differences observed after treatment or exposure.     

MOSFET中1/f噪声的Hooge参数α_H

本文报道 P 沟道 MOSFET 器件中 1/f 噪声 Hooge 参数测量的部分实验结果.由加利福尼亚州的 SILICONIX 公司提供的实验样品是采用同样工艺作在同一块基片之上的.实验表明,在由非谐和状态到谐和状态过渡时,α_H 与沟道长度的平方成正比.类似的结果未曾见报道.     

Distribution of the cross-correlations of squared residuals in ARIMA models

ABSTRACT The distribution of the cross-correlations of squared residuals from Box-Jenkins models is considered in very general conditions, and the asymptotic distribution is derived. A test for a lagged relationship in volatility for economic time series under instantaneous causality is proposed, and its empirical behaviour is studied. An example involving the international stock market's volatility is studied, and an interesting result is observed.     

益气补肾活血法治疗小儿哮喘的临床研究

探讨益气补肾活血法对支气管哮喘患儿血内皮素-1(ET-1)、一氧化氮(NO)和内皮细胞(CEC)变化的影响.应用放射免疫法、硝酸还原法和Hladovec法对加服中药的100例支气管哮喘患儿于急性期、恢复期等分别检测血ET-1、NO和CEC.与未加服中药的支气管哮喘患儿比较,其恢复期和1年后血ET-1、NO和CEC水平明显下降,发作次数明显减少,有显著性差异.益气补肾活血中药可降低支气管哮喘患儿血ET-1、NO的合成,减轻肺血管内皮细胞的损伤.对防治小儿支气管哮喘有效.     

PAI-1、t-PA/PAI-1比值与急性血管事件的相关性研究

目的了解血浆t-PA、PAI-1和t-PA/PAI-1比值在急性血管事件中的变化和意义。方法对于健康对照组、陈旧性和急性血管事件组分别采用ELISA法检测t-PA和PAI-1活性,计算t-PA/PAI-1比值。结果急性血管事件组血浆t-PA、PAI-1明显增高、t-PA/PAI-1比值明显降低,与其它两组相比P<0.01;陈旧性血管事件组血浆PAI-1增高,与对照组相比P<0.05;t-PA升高和t-PA/PAI-1比值降低,与对照组相比无显著差异。结论血浆t-PA和PAI-1水平与血管内皮稳定性密切相关。PAI-1增高和t-PA/PAI-1比值降低的程度在急性血管事件发生中起着重要的作用。监测PAI-1和t-PA/PAI-1比值这两项指标,在心脑血管事件的预防和治疗方面具有重要意义。     

Doubly periodic non-homogeneous Poisson models for hurricane data

Non-homogeneous Poisson processes with periodic claim intensity rate have been proposed as claim counts in risk theory. Here a doubly periodic Poisson model with short- and long-term trends is studied. Beta-type intensity functions are presented as illustrations. The likelihood function and the maximum likelihood estimates of the model parameters are derived.Doubly periodic Poisson models are appropriate when the seasonality does not repeat exactly the same short-term pattern every year, but has a peak intensity that varies over a longer period. This reflects periodic environments like those forming hurricanes, in alternating El Niño/La Niña years. An application of the model to the data set of Atlantic hurricanes affecting the United States (1899–2000) is discussed in detail.     

The protestant work ethic,human values and attitudes towards taxation

The literature on demographic determinants of attitudes towards taxation was briefly reviewed. Whereas most previous concerned the relationship between such things as income, vote etc. and tax attitudes, this study examined the relationship between Protestant Work Ethic beliefs, social value systems and attitudes toward taxation. It was demonstrated that subjects who strongly endorsed the Protestant Work Ethic were more opposed to taxation than those who did not strongly endorse these beliefs. Further many of the instrumental and terminal value systems of subjects who were pro-taxation were significantly different from those who were anti-taxation. The results are discussed in terms of the psychology of lay-economic beliefs and implications for social change were noted.     

Bernoulli Processes with Non-Positive Correlations

We deal with sequences of dependent Bernoulli variables with non positive correlations. Some special models for 1-dependent and 2-dependent 0–1 valued variables are analyzed, namely Bernoulli variables obtained by clipping a linear combination of iid variables. Formulas describing dependence of their correlation function on the clipping parameters are derived. The lower bound for the sum of autocorrelations of Bernoulli variables obtained by clipping a Gaussian process is provided.