Rehabilitation of disorders of the breaking of voice

The adolescent's breaking of the voice is the result of the substitution of the chest voice (or heavy mechanism) for the head voice (or light mechanism). In cases of late breaking, the voice is abnormally high-pitched and feeble, often with a distorted timbre, while the larynx is normal and pubescent. Such people are generally not fully aware of their voices' real nature. Therapy classically resorts to laryngeal manipulations, of which a new technique is put forward. Another therapeutic approach is based, on the one hand, on critical listening compared with a control male voice, thus enabling the subject to become aware of his own voice, and, on the other hand, on high intensity work which helps passing from head to chest voice.     

Congenital pseudarthrosis of the clavicle

Congenital pseudarthrosis of the clavicle is a rare anomaly in which the clavicle is formed in utero in two separate segments. Clinically, there is a bump and a palpable discontinuity at the middle of the clavicle. There is no swelling or tenderness, nor disability. Radiologically, the medial ends of both clavicular segments are blunt and there is no interruption of cortical bone. The differential diagnosis includes birth fracture of the clavicle and craniocleidal dysostosis. The obstetrician should be aware of this condition as, if it is misdiagnosed, he may be wrongly accused of birth fracture.     

液体低温热导率的测试

介绍了非稳态法测试液体在低温下（－１００～５０℃）的热导率的测试原理、方法，测试了全氟三乙胺的低温热导率。为了提高测试的重复性，采用了相对比较法，并给出了测试装置及测试结果和误差分析。     

砼坝裂缝稳定性分析

通过比较线弹性断裂力学中的两种计算应力强度因子的方法，外推法和奇异单元法，得到相应的结论；并以某砼坝下游部位出现裂缝为例，分析在不利荷载作用下裂缝的稳定性。     

Effects of interstitial oxygen on microstructure and mechanical properties of Ti-48Al-2Cr-2Nb with fully lamellar and duplex microstructures

The effect of added oxygen in the range of 1000 to 4000 wt ppm on the microstructures of a Ti-48Al-2Cr-2Nb alloy has been investigated and compared to the microstructures for a high-purity alloy. For specimens cooled from theα phase, interstitial oxygen stabilizes the lamellar microstructure with respect toγ grains, with higher than equilibrium values for theα ₂ volume fraction. For specimens cooled from theα +γ phase field, the lamellar microstructure still tends to be favored by oxygen, but it is found that the phase volume fractions are not significantly different from equilibrium values. This suggests that interstitial O essentially reduces the kinetics of theα toα +γ transformation. Thus, interstitial oxygen will have a strong effect on microstructures obtained by continuous cooling fromα, but significantly less on those, such as the duplex microstructure, obtained by long treatment in theα +γ phase field. In general, increased O content is well correlated with reduced ductility. Finally, the role of interstitial oxygen on this phase transformation is discussed.     

一种高性能超宽带线性调频信号源

介绍一种VHF／UHF频段高性能超宽带线性调频信号源的设计与实现。首先简要阐述了高性能超宽带线性调频信号源的设计思想，然后依据基带数字产生结合倍频扩展带宽的思路提出了一种超宽带线性调频信号产生方案，并进行了设计实现研究。测试结果表明：按照本文阐述的指导思想和实现方案所设计的超宽带线性调频信号源达到 了相当高的性能。     

Contribution of beta-lactamase production to the resistance of mycobacteria to beta-lactam antibiotics

Changes in motor function were assessed in male rats after injecting graded doses (100, 200, 400, and 800 mg/kg, IP) of ammonium chloride and ammonium acetate. The effects were correlated with the concentrations of ammonia and glucose in the brain and blood. Spontaneous motor activity and motor coordination were inhibited after injecting 100 and 200 mg/kg, whereas with 400 and 800 mg/kg the animals exhibited convulsive movements. A dose-dependent increase was found in the concentrations of ammonia and glucose in both blood and brain. These were restored, 25 min after treatment, to control levels in the blood and not in the brain. A correlation was found between the time courses of inhibitory motor events and a rise in brain ammonia levels. Convulsant action of ammonium salts was accompanied by a marked elevation of ammonia and glucose concentration in the brain. The findings suggest that detoxication of diffused ammonia is a rate-limiting process in the brain and that ammonia, at toxic concentrations, decreases glucose utilization in the brain, resulting in an inhibition of motor function. A very high concentration of ammonia in the brain, although inhibiting glucose utilization, produces clonic convulsions probably by activating directly the motor neurons.     

高码率DQPSK遥测信号解调方法研究

本文根据高码速率 DQPSK遥测信号的特点 ,介绍了一种通过数字瞬时测频来完成对高码速率 DQPSK信号解调的方法。该方法算法简单 ,处理速度快 ,误码率低 ,能够有效地抑制多普勒频率对解调的影响 ,便于数字信号处理芯片硬件实现。同时给出了解调的仿真结果