双旋Y切石英振子厚度模式的频温特性的研究

本文利用描述固体中弹性声波的克里斯托费尔方程,建立了双旋Y切石英振子厚度模式的频温特性分析方法,并编制了相应的计算机程序。该程序可给出双旋Y切石英振子在任意切角(ф_3ф_1)下的厚度模(a、b、c模)的频率温度特性曲线。文中给出了单旋AT切、BT切(b模)、双旋SC切(b、c模)、FC切、IT切、LC切、NL_1切、NL_2切、AK切等各已知切型的频温特性曲线。对石英谐振器的切角灵敏度和切角误差进行了分析。     

Explaining Differences in Economic Performance Among Racial and Ethnic Groups in the USA

A bstract . By utilizing self-reported race and ancestry in the 1980 and 1990 USA censuses and the Blinder-Oaxaca decomposition technique, the extent of wage discrimination experienced by women and by men is examined across 50 ethnic/racial groups. Systematic evidence of negative discrimination is revealed in both census years for Asian, Indian, black (African-American), Vietnamese, Cuban, Mexican, Puerto Rican , and Native American males. To assess the charge that the Blinder-Oaxaca decomposition indicates cultural rather than discriminatory differentials, two additional data experiments are performed—one that controls for color and varies culture, and one that controls for culture and varies color. Race appears to matter.     

Changes in REIT Liquidity 1990–1994: Evidence from Intra-day Transactions

This study uses data on intra-day transactions to analyze whether real estate investment (REIT) liquidity as measured by the bid-ask spread changed from 1990 to 1994, a period during which the industry's market capitalization increased from $8.7 billion to $45 billion. REIT percentage spreads (spread as percentage of share price) narrowed significantly, primarily attributable to higher share prices rather than narrower dollar-value spreads. An empirical model is used to analyze the determinants of percentage spreads. Return variance and share price, not market capitalization are found to be the primary determinants of percentage spreads in both periods. This suggests that the liquidity of REIT securities is similar to that of non-REIT securities with similar prices and return variance. In addition, percentage spreads are wider for REITs trading on the NASDAQ.     

The Dynamics of Alliance Conditions in the Alliance Development Process

One of the key issues in understanding the developmental processes of strategic alliances is how the alliance conditions change over the different stages of alliance development. A related question concerns the nature of the co-evolutionary dynamics of alliances in terms of their constituent partner firms. In this article we propose an integrated process model of alliances that is based on alliance conditions, allianc developmental stages, and an alliance system comprising co-evolutionary elements. We suggest that alliance conditions, or the key characteristics of an alliance at any given moment, link the alliance environment (firm characteristics) and the alliance development process. We also explore how specific patterns of alliance conditions have differential impacts on the interactive elements of the alliance co-evolutionary system.     

On the E-optimality of truncated block designs

Sufficient conditions are found for designs, derived from completely symmetric designs by deleting binary blocks, to be E-optimal. Sufficient conditions are also found for E-optimality of designs obtained from other E-optimal designs by deleting all blocks forming a balanced incomplete block design on a subset of the treatments. The results include many binary and non-binary designs for which E-optimality was previously unknown.     

我国市场经济的历史起点与发展阶段的选择

国际上市场经济经历了萌芽阶段、初级阶段、发展阶段、发达阶段,各阶段的依据是不同生产力性质、不同生产关系形式以及商品生产和商品交换的不同水平.我国市场经济的历史起点应是三个:一是从计划经济开始向市场经济转化,二是从自然经济向商品经济转化,三是从小商品经济(或简单商品经济)向大商品经济或市场经济转化.我国市场经济发展阶段的战略选择,应该是分类定位和分类发展,采取多层次多样化的市场经济的发展阶段.     

Combining information for prediction in linear regression

This article deals with the prediction problem in linear regression where the measurements are obtained using k different devices or collected from k different independent sources. For the case of k=2, a Graybill-Deal type combined estimtor for the regression parameters is shown to dominate the individual least squares estimators under the covariance criterion. Two predictors ŷ _c and ŷ _p are proposed. ŷ _c is based on a combined estimator of the regression coefficient vector, and ŷ _p is obtained by combining the individual predictors from different models. Prediction mean square errors of both predictors are derived. It is shown that the predictor ŷ _p is better than the individual predictors for k≥2 and the predictor ŷ _c is better than the individual predictors for k=2. Numerical comparison between ŷ _c and ŷ _p shows that the former is superior to the latter for the case k=2.     

A Study of Arbitrage Efficiency Between the FTSE‐100 Index Futures and Options Contracts

Despite the importance of the London markets and the significance of the relationship for market makers, little published research is available on arbitrage between the FTSE‐100 Index futures and the FTSE‐100 European index options contracts. This study uses the put–call–futures parity condition to throw light on the relationship between options and futures written against the FTSE Index. The arbitrage methodology adopted in this study avoids many of the problems that have affected prior research on the relationship between options or futures prices and the underlying index. The problems that arise from nonsynchroneity between options and futures prices are reduced by the matching of options and futures prices within narrow time intervals with time‐stamped transaction data. This study allows for realistic trading and market‐impact costs. The feasibility of strategies such as execute‐and‐hold and early unwinding is examined with both ex‐post and ex‐ante simulation tests that take into consideration possible execution time lags for the arbitrage trade. This study reveals that the occurrence of matched put–call–futures trios exhibits a U‐shaped intraday pattern with a concentration at both open and close, although the magnitude of observed mispricings has no discernible intraday pattern. Ex‐post arbitrage profits for traders facing transaction costs are concentrated in at‐the‐money options. As in other major markets, despite important microstructure differences, opportunities are generally rapidly extinguished in less than 3 min. The results suggest that arbitrage opportunities for traders facing transaction costs are small in number and confirm the efficiency of trading on the London International Financial Futures and Options Exchange. © 2002 John Wiley & Sons, Inc. Jrl Fut Mark 22:31–58, 2002     

Are Fundamentals Priced in the Bond Market?*

To date, the discussion of the Lev and Thiagarajan 1993 fundamentals in the prior literature has been exclusively in the context of the stock market. Our study is the first to examine the value‐relevance of these fundamentals for default risk. By focusing on the market for new bond issues, we examine the value‐relevance of the fundamental score using expected rather than realized returns. Also, by focusing on the bond market we provide a different perspective than that brought by prior studies relying solely on stock prices. We find the fundamentals to be priced in the market for new bond issues as indicators of expected future earnings and to be value‐relevant in enabling the market to discern differences in bond credit quality over and above the published bond ratings.