Metal-induced negative oxide charge detected by an alternating current surface photovoltage in thermally oxidized Fe-contaminated n-type Si (001) wafers

The atomic-bridging type negative oxide charge in SiO₂ is investigated using the Fe-contaminated (001) surface of n-type Si wafers. The investigation is done on the basis of a chemical analysis and a method in which the frequency-dependent alternating current (AC) surface photovoltage (SPV) is measured. At room temperature, an AC SPV appears and gradually increases, saturating after approximately one day (with an Fe concentration on the Si surface of 4.0 × 10¹³ atoms/cm²). The AC SPV eventually becomes inversely proportional to frequency except at very low frequencies (< 10 Hz) corresponding to weak or strong inversion, indicating that the negative Fe induced oxide charge appears in the form of a (FeOSi)⁻ network. Also, in Fe-contaminated n-type Si(001) surfaces thermally oxidized at between 550 and 650 °C for 60 min, strong inversion is unquestionably observed, proving that the (FeOSi)⁻ network survives and that most of the added Fe has segregated into the region closest to the surface of the thin SiO₂ film. At 850 °C and/or for long oxidation times, the AC SPV decreases and ultimately disappears, implying that the (FeOSi)⁻ network has collapsed and may have changed into Fe₂O₃. A model for the metal-induced negative oxide charge in the conventional oxide charge diagram is proposed.     

极低频信号的一种离散频谱校正新方法

对于振动工程中常见的极低频、极短时、极高频(接近奈奎斯特频率)等极端频率信号,常用的离散频谱分析与校正方法存在较大误差.对极端频率信号的典型情形进行了分析,针对极端频率信号中的极低频信号,提出了一种计及负频率成分干涉影响的离散频谱校正新方法.该方法基于Blackman窗,利用局部谱峰附近的三条谱线,建立包含正负频率贡献的离散频谱校正模型,通过对模型的求解获得频率、幅值和相位校正公式.采用频段内扫描的方式对频谱校正公式进行了仿真验证,结果表明所提方法有效降低了负频率成分的干涉影响,对极低频信号的频率、幅值和相位校正有较高的精度.     

标气动态发生系统的负压吸动式雾化发生池

提出了一种新型的负压吸动式雾化发生池,主要应用于气源常温下为液态的标气发生系统中。介绍其结构和运行的原理,在实验的基础上,分析了实验数据,选择最佳的孔径参数值,达到最好的雾化效果。该发生池最终成功应用于标气动态发生系统中,运行稳定,取得了良好的效果。     

一种非线性隔振器的静力分析与实验研究

研究一种变刚度非线性隔振器,使该隔振器具有高静刚度低刚度的效果。根据水平铰支梁受水平力弯曲理论、刚度并联理论,分析斜薄壁梁在竖直方向力的作用下的力位移以及刚度位移特性,得到斜薄壁梁结构在竖直力作用下具有负刚度特性。通过与弹簧（正刚度）结构并联,理论结合实验验证一种并联结构隔振器样机,得到该样机具有高静刚度－小静变形,低动刚度－力的变化率很小。     

Si thin platelets as high-capacity negative electrode for Li-ion batteries

Pure Si platelets and Ni or Cu layer-laminated Si platelets with difference thickness were prepared, and their charge/discharge properties were examined in 1 M LiClO₄/EC + DEC (1:1 by volume) as alternative negative electrode materials to graphite for Li-ion batteries. The shape of thin platelets and lamination with Ni layer are significantly effective to improve the cycleability in Li-Si alloy system by relieving the stress during the alloying/de-alloying processes, reinforcing the mechanical strength and reducing the Li⁺ ion diffusion length. Moreover, the first irreversible capacity is minimized by reduction of the amount of Ketjen Black (KB) in the composite electrode because of electrolyte decomposition on the surface of KB. Consequently, the Si/Ni/Si-LP30 (30/30/30 nm) composite electrode with 5 wt% KB also exhibits over 700 mAh g⁻¹ even after 50 cycles in 1 M LiPF₆/EC + DEC (1:1).     

Disclosure of emotional events in groups at risk for posttraumatic stress disorder.

The disclosure of emotional events to various social intimates (disclosure targets) was measured in 2 samples (soldiers and first responders) at risk for posttraumatic stress disorder (PTSD), as well as a comparison sample of college students. These 3 groups completed survey measures of disclosure, and at risk groups also completed measures of PTSD symptoms and social support. Groups at risk for PTSD were less likely to disclose emotions related to potentially traumatic events than were college students reporting general emotional disclosure. Overall, disclosure of positive emotions was more likely than disclosure of negative emotions. Furthermore, amount of disclosure depended on the person to whom the individual disclosed. Within groups at risk for PTSD, social support was associated with lower levels of PTSD. However, this relationship was mediated by emotional disclosure to each target. Disclosure of positive emotions generally was associated with lower levels of PTSD, and disclosure of negative emotions to those with similar at-risk status was associated with greater levels of PTSD. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

广钢转炉除尘系统设备及工艺改进

介绍了广钢转炉一次除尘系统的设备及工艺改进。广钢针对其转炉除尘系统存在的问题,通过加强转炉煤气回收各项措施的落实,净化了转炉烟气,提高了一氧化碳含量,实现了转炉负能炼钢。     

矿井风速传感器的设计

矿井风速的监测是保证矿井安全生产的重要因素,矿井的工作条件特殊,工作环境复杂,风速测量在矿井安全中是一项重要内容,介绍了采用负温度系数热敏电阻器为检测元件的风速传感器的测量原理,得出了风速与热敏电阻变化的关系,阐述了风速测量原理。     

负压风筒在掘进大转角局部通风巷道中的应用

针对掘进局部通风中大角度转弯巷道存在通风阻力大,漏风大的问题,提出了用负压风筒解决掘进巷道大角度转弯巷道中局部通风存在的问题,成功应用在实际工作中,并在掘进工作面推广应用。     

Negative effects from psychological treatments: A perspective.

The author offers a 40-year perspective on the observation and study of negative effects from psychotherapy or psychological treatments. This perspective is placed in the context of the enormous progress in refining methodologies for psychotherapy research over that period of time, resulting in the clear demonstration of positive effects from psychological treatments for many disorders and problems. The study of negative effects—whether due to techniques, client variables, therapist variables, or some combination of these—has not been accorded the same degree of attention. Indeed, methodologies suitable for ascertaining positive effects often obscure negative effects in the absence of specific strategies for explicating these outcomes. Greater emphasis on more individual idiographic approaches to studying the effects of psychological interventions would seem necessary if psychologists are to avoid harming their patients and if they are to better understand the causes of negative or iatrogenic effects from their treatment efforts. This would be best carried out in the context of a strong collaboration among frontline clinicians and clinical scientists. (PsycINFO Database Record (c) 2010 APA, all rights reserved)