STUDY ON PHASE PERCEPTION IN SPEECH

The perceptual effect of the phase information in speech has been studied by auditory subjective tests. On the condition that the phase spectrum in speech is changed while amplitude spectrum is unchanged, the tests show that: (1) If the envelop of the reconstructed speech signal is unchanged, there is indistinctive auditory perception between the original speech and the reconstructed speech; (2) The auditory perception effect of the reconstructed speech mainly lies on the amplitude of the derivative of the additive phase; (3) td is the maximum relative time shift between different frequency components of the reconstructed speech signal. The speech quality is excellent while td <10ms; good while 10ms< td <20ms; common while 20ms< td <35ms, and poor while td >35ms.     

空心微珠改性硬质聚氯乙烯复合材料的应用研究

经过改性的超细空心微珠可以作为填料加入到硬质聚氯乙烯（PVC－U）树脂中，同时改善PVC树脂的流变性、冲击性能和刚性等性能。研究结果表明，超细空心微珠加入到硬质PVC管材中，可以明显改善PVC硬管的加工流动性能，显著缩短塑化时间，降低最大扭矩。而超细空民微珠加入到硬质PVC板材时，可以提高PVC硬板的冲击性能，减小制品的收缩率，赋予PVC硬板优异的耐腐蚀性能，且产品的各项性能均符合PVC板材国家标准GB／T4454－96。     

尼龙6/马来酸酐-苯乙烯多单体接枝聚丙烯反应共混物

用双螺杆挤出机制备了聚丙烯(PP)与尼龙6(PA6)的共混物．先用多组分熔融接枝的方法将马来酸杆（MAH）和苯乙烯（St）共同接枝于聚丙烯（PP）上，制得多单体接枝聚丙烯PP-g-(MAH-St），该接枝物具有较高的MAH接枝率。利用MFR、SEM、TEM和力学性能测试等分析方法，研究了多组分熔融接枝聚丙烯PP-g-(MAH-St)对PA6/PP共混物的形态结构和力学性能等的影响。结果表明，PP-g-(MAH-St)中的酸酐基团与PA6末端的氨基发生化学反应，原位形成的PP-PA6共聚物能有效地改善PA6与PP的相容性，可以使PP均匀地分散在PA6基体中，相区尺寸明显减小，可至0.1μm，并使共混物的力学性能得到均衡的提高，冲击韧性的提高尤其显著，达到了橡胶改性所难以达到的效果。     

Sites of alcohol and volatile anaesthetic action on GABA(A) and glycine receptors

Volatile anaesthetics have historically been considered to act in a nonspecific manner on the central nervous system. More recent studies, however, have revealed that the receptors for inhibitory neurotransmitters such as gamma-aminobutyric acid (GABA) and glycine are sensitive to clinically relevant concentrations of inhaled anaesthetics. The function of GABA(A) and glycine receptors is enhanced by a number of anaesthetics and alcohols, whereas activity of the related GABA rho1 receptor is reduced. We have used this difference in pharmacology to investigate the molecular basis for modulation of these receptors by anaesthetics and alcohols. By using chimaeric receptor constructs, we have identified a region of 45 amino-acid residues that is both necessary and sufficient for the enhancement of receptor function. Within this region, two specific amino-acid residues in transmembrane domains 2 and 3 are critical for allosteric modulation of both GABA(A) and glycine receptors by alcohols and two volatile anaesthetics. These observations support the idea that anaesthetics exert a specific effect on these ion-channel proteins, and allow for the future testing of specific hypotheses of the action of anaesthetics.     

微波消解-ICP-AES法测定菜油中P、S

采用微波加热,在高温高压下酸消解样品,运用电感耦合等离子体原子发射光谱法(ICP-AES)同时测定菜油中P、S。本法选用紫外区谱线P178.221nm、S180.669nm,避免了基体中存在的Fe、Zn、Al、Cu、Mn、Ca等元素的光谱干扰。实验通过用纯氮吹扫光谱仪光路的方法消减空气中氧对紫外线的吸收,获得了足够的灵敏度。该方法简便、快速,稳定可靠,P、S检出限分别为0.067、0.078μg/ml,RSD为1.35%～5.05%,回收率为89.0%～100.9%。     

关于电视群信号对光纤副载波调频传输中的信噪比平衡问题的分析

本文对微波副载波用电视群信号调频的光纤传输中的信噪比平衡问题进行了分析,推导出VSB-AM信号在解调后的信噪比表达式,引入了信噪比恶化系数的概念.为了实现多路VSB-AM信号间的信噪比的平衡,相应的微波副载波频偏应有确定的比例关系.     

Calderón-Zygmund型算子的研究

本文对通常的Calderón-Zygmund型算子稍加改造,仍得到满意结果.     

The geometry effects for stress intensity factor of sandwich specimen for measuring interfacial fracture toughness

The interfacial stress intensity factors for three types of sandwich specimens: the single edge crack tensile specimen, the three point bend specimen and the four point shear specimen were obtained by the finite element analysis and compared with the asymptotic solutions. The results show that the geometric effect for mode II specimen is larger than mode I specimen. The limit curves for geometry factor equal to 1.05 were obtained to indicate the usable range of validity of the asymptotic solution.     

余热利用系统多目标优化模型及应用

以炭黑生产中的余热利用系统为背景建立了余热利用系统多目标优化规划数学模型;阐述了模型的求解方法;给出了实例分析。