利用反馈实现压控振荡器V-f特性的线性化

介绍一种利用反馈控制实现压控振荡器V-f特性线性化的方法，并给出具体电路。这种方法适用于具有任意V-f特性的VCO，通用性较强，具有很好的实用价值。     

新型大功率长脉冲速调管的研制

给出一种新型的Ｓ波段大功率长脉冲速调管的设计、工艺和测试结果。该管在ＨＬ－１Ｍ托卡马克装置上成功地用于核聚变的低杂波电流驱动（ＬＨＣＤ）实验。     

并行采集系统通道失配误差测量及校正

并行时间交替采样结构是一种有效地提高采样率的方法,但在采用此结构的采集系统中,多个ADC通道间的失配误差严重影响采集系统的性能,国内外对失配误差的测量和校正多采用加测试信号的方法。该文通过理论分析得出一种不需要测试信号且适用信号范围广泛的误差测量算法,并对国外文献中盲算法估计时间误差的方法进行了改进。计算机仿真证实了该方法对误差的估计有极高的精确度,能有效地提高采集系统性能。     

Global and local statistical properties of fixed-length nonparametric smoothers

The main purpose of this study is to analyze the global and local statistical properties of nonparametric smoothers subject to a priori fixed length restriction. In order to do so, we introduce a set of local statistical measures based on their weighting system shapes and weight values. In this way, the local statistical measures of bias, variance and mean square error are intrinsic to the smoothers and independent of the data to which they will be applied on. One major advantage of the statistical measures relative to the classical spectral ones is their easiness of calculation. However, in this paper we use both in a complementary manner. The smoothers studied are based on two broad classes of weighting generating functions, local polynomials and probability distributions. We consider within the first class, the locally weighted regression smoother (loess) of degree 1 and 2 (L1 and L2), the cubic smoothing spline (CSS), and the Henderson smoothing linear filter (H); and in the second class, the Gaussian kernel (GK). The weighting systems of these estimators depend on a smoothing parameter that traditionally, is estimated by means of data dependent optimization criteria. However, by imposing to all of them the condition of an equal number of weights, it will be shown that some of their optimal statistical properties are no longer valid. Without any loss of generality, the analysis is carried out for 13- and 9-term lengths because these are the most often selected for the Henderson filters in the context of monthly time series decomposition. We would like to thank an Associate Editor and an anonymous referee for their valuable comments on an earlier version of this paper. Financing from MURST is also gratefully acknowledged.     

The Freshman 15—A Closer Look

Abstract

Objectives and Participants: Changes in body weight, composition, and size were examined in college freshmen at the beginning (initial, n = 240) and end of fall semester 2007 (n = 214) and the end of spring semester 2008 (n = 205). Methods: Height, weight, body composition, and waist and hip measurements were assessed. Results: Mean weight, body mass index (BMI), absolute and percent body fat all increased significantly over fall semester and the academic year. About 31% of freshmen lost ≥5 lbs. Mean academic year weight gain was 2.6 lbs (entire group) and 6.0 lbs (weight gainers); body fat increased by 4.4 lbs in the weight gainers. A significant correlation (r = .509) was found between weight change and waist circumference change, but not between weight change and waist to hip ratio change. Conclusions: Freshmen weight gain is associated with increases in body fat and waist circumference, which may be troublesome should the trend continue throughout college.     

Effect of body image on gestational weight gain in overweight and obese women

Problem or backgroundThere is little information available describing how women who are overweight or obese in pregnancy perceive their bodies, and in particular the effect of body image dissatisfaction on gestational weight gain.QuestionTo describe how women who are overweight or obese in pregnancy perceive their body, and the effect of body image on gestational weight gain.MethodsThis prospective nested cohort study evaluated self estimation of body weight, preferred body shape, dieting behavior, satisfaction with body weight and shape, and gestational weight gain in pregnant women who were overweight or obese, through self-completed questionnaire in early pregnancy in South Australia from October 2010 to February 2012.FindingsOf the 442 women who completed the questionnaire, 25.8% correctly identified their BMI, with 70.1% under-estimating and 4.1% over-estimating their BMI. Women who were obese were significantly less likely to correctly identify their BMI, as were younger women. Women who incorrectly identified their BMI were significantly more likely to have higher gestational weight gain (P < 0.001). Approximately 45% of women indicated dissatisfaction with their weight or body shape, with this being more common in women of higher parity and higher BMI. Dissatisfaction was significantly related to gestational weight gain.ConclusionWomen who report increasing dissatisfaction with their body size and shape are more likely to gain excessive weight during pregnancy. Further research should explore insights about maternal body image and diet related behaviors.     

掩饰、隐瞒犯罪所得、犯罪所得收益罪的行为对象

掩饰、隐瞒犯罪所得、犯罪所得收益罪的行为对象是"犯罪所得"与"犯罪所得收益"。"犯罪所得"与"犯罪所得收益"中的"犯罪"是刑事实体法意义上的犯罪,不限于财产犯罪。"犯罪所得"是他人既遂犯罪行为之所得,是犯罪行为直接之所得,转化物、交易物、具有有形载体的财产性利益以及部分违禁品都可以成为犯罪所得。"犯罪所得收益"是犯罪所得所产生的孳息,包括犯罪所得产生的天然孳息与法定孳息两类。     

On a measure of information gain for regression models in survival analysis

Papers dealing with measures of predictive power in survival analysis have seen their independence of censoring, or their estimates being unbiased under censoring, as the most important property. We argue that this property has been wrongly understood. Discussing the so-called measure of information gain, we point out that we cannot have unbiased estimates if all values, greater than a given time τ, are censored. This is due to the fact that censoring before τ has a different effect than censoring after τ. Such τ is often introduced by design of a study. Independence can only be achieved under the assumption of the model being valid after τ, which is impossible to verify. But if one is willing to make such an assumption, we suggest using multiple imputation to obtain a consistent estimate. We further show that censoring has different effects on the estimation of the measure for the Cox model than for parametric models, and we discuss them separately. We also give some warnings about the usage of the measure, especially when it comes to comparing essentially different models.     

长期住院治疗的精神分裂症患者代谢综合征风险研究

目的调查长期服用抗精神病药的精神分裂症患者在糖脂代谢相关变量的情况及相关风险的评估,以便为进一步研究抗精神病药与代谢综合征发生的因果关系提供初步的调查线索。方法以上海市精神卫生中心住院诊断为精神分裂症且持续服用治疗剂量抗精神病药至少6个月以上而以往无代谢障碍的患者为调查对象,在6个病房中进行筛选,符合条件共170人,调查包括人口学资料(身高,体重,腰围,用药时间,糖尿病家族史)、最近一月的血脂水平(HDL,TG)、空腹血糖和血压等情况。结果精神分裂症患者中男性较女性更易罹患代谢综合征(P<0.01);精神分裂症患者中的吸烟者较不吸烟者更易罹患代谢综合征(P<0.05);而药物之间的比较并无显著性差异(P>0.05)。结论经典和非典型抗精神病药可能会引起代谢综合征或加重其发生的风险。     

基于数字补偿的实时自动增益控制技术研究

阐述了基于前馈技术的实时自动增益控制的原理及同步和数字补偿等关键技术的实现;介绍了在通信分析仪中的具体应用。采用的实时自动增益控制电路利用信号通路的延迟特性,精确控制模数转换器同步,实时调整信号增益,在数字域补偿误差,扩展系统动态范围。该技术成功应用于通信分析仪,并在雷达、电子对抗和接收机中得到推广。