畸变产物耳声放射法在新生儿听力筛查中的应用价值

目的应用畸变产物耳声发射法对新生儿进行听力筛查,探讨其在小儿听力障碍诊断、干预中的应用价值。方法对1170例婴儿采用畸变产物耳声发射法进行听力筛查,对第一次筛查未通过者,与出院前和出生后42 d分别进行复查,若两次复查仍未通过,则通过脑干听觉诱发电位进行确诊。结果 1170例婴儿通过检测,通过率为96.8%,未通过率为3.2%。经过脑干反应检查异常者3例,听力障碍发生率为2.56‰,其中单耳聋为2例,双耳聋为1例。结论畸变产物耳声发射法适合小儿听力筛查,有利于及早发现儿童听力障碍,以便早期进行干预。

A 2.4GHz CMOS Monolithic Transceiver Front-End for IEEE 802.11b Wireless LAN Applications

A 2. 4GHz CMOS monolithic transceiver front-end for IEEE 802. llb wireless LAN applications is presented. The receiver and transmitter are both of superheterodyne structure for good system performance. The frontend consists of five blocks., low noise amplifier,down-converter, up-converter, pre-amplifier, and LO buffer. Their input/output impedance are all on-chip matched to 50 Ω except the down-converter which has open-drain outputs. The transceiver RF front-end has been implemented in a 0. 18μm CMOS process. When the LNA and the down-converter are directly connected, the measured noise figure is 5.2dB, the measured available power gain 12. 5dB, the input l dB compression point --18dBm,and the third-order input intercept point --7dBm. The receiver front-end draws 13.6mA currents from the 1.8V power supply. When the up-converter and pre-amplifier are directly connected, the measured noise figure is 12.4dB, the power gain is 23. 8dB, the output ldB compression point is 1.5dBm, and the third-order output intercept point is 16dBm. The transmitter consumes 27.6mA current from the 1.8V power supply.

Design of Low-Voltage Low Noise Amplifiers with High Linearity

A CMOS radio frequency low noise amplifier with high linearity and low operation voltage of less than 1.0V is presented.In this circuit,an auxiliary MOSFET in the triode region is used to boost the linearity.Simulation shows that this method can boost the input-referred 3rd-order intercept point with much less power dissipation than that of traditional power/linearity tradeoff solution which pays at least 1dB power for 1dB linearity improvement.It is also shown that the size of the common-gate PMOS transistor needs to be optimized to reduce its loaded input impedance so as not to degrade the linearity due to high voltage gain at its source terminal.The simulation is carried out with TSMC 0.18μm RF CMOS technology and SpectreRF.

Color Doppler sonography and angioscintigraphy in hepatic Hodgkin's lymphoma

AIM： To estimate the characteristics of Color Doppler findings and the results of hepatic radionuclide angiography （HRA） in secondary Hodgkin＇s hepatic lymphoma. METHODS： The research included patients with a diagnosis of Hodgkin＇s lymphoma with metastatic focal lesions in the liver and controls. Morphologic characteristics of focal liver lesions and hemodynamic parameters were examined by pulsed and Color Doppler in the portal, hepatic and splenic veins were examined. Hepatic perfusion index （HPI） estimated by HRA was calculated. was observed. Lesions were mostly hypoechoic and mixed, solitary or multiple. Some of the patients presented with dilated splenic veins and hepatofugal blood flow. A pulse wave was registered in the centre and at the margins of lymphoma. The average velocity of the pulse wave was higher at the margins （P 〉 0.05）. A continuous venous wave was found only at the margins of lymphoma. There was no linear correlation between lymphoma size and velocity of pulse and continuous wave （r = 390, P 〈 0.01）. HPI was significantly lower in patients with lymphomas than in controls （P 〈 0.05）, pointing out increased arterial perfusion in comparison to portal perfusion. CONCLUSION： Color Doppler ultrasonography is a sensitive method for the detection of neovascularization in Hodgkin＇s hepatic lymphoma and estimation of its intensity. Hepatic radionuclide angiography can additionally help in the assesment of vascularisation of liver lesions.

Clinical value of liver and spleen shear wave velocity in predicting the prognosis of patients with portal hypertension

AIM To explore the relationship of liver and spleen shear wave velocity in patients with liver cirrhosis combined with portal hypertension,and assess the value of liver and spleen shear wave velocity in predicting the prognosis of patients with portal hypertension.METHODS All 67 patients with liver cirrhosis diagnosed as portal hypertension by hepatic venous pressure gradient in our hospital from June 2014 to December 2014 were enrolled into this study. The baseline information of these patients was recorded. Furthermore,67 patients were followed-up at 20 mo after treatment,and liver and spleen shear wave velocity were measured by acoustic radiation force impulse at the 1^(st) week,3^(rd) month and 9^(th) month after treatment. Patients with favorable prognosis were assigned into the favorable prognosis group,while patients with unfavorable prognosis were assigned into the unfavorable prognosis group. The variation and difference in liver and spleen shear wave velocity in these two groups were analyzed by repeated measurement analysis of variance. Meanwhile,in order to evaluate the effect of liver and spleen shear wave velocity on the prognosis of patients with portal hypertension,Cox's proportional hazard regression model analysis was applied. The ability of those factors in predicting the prognosis of patients with portal hypertension was calculated through receiver operating characteristic(ROC) curves.RESULTS The liver and spleen shear wave velocity in the favorable prognosis group revealed a clear decline,while those in the unfavorable prognosis group revealed an increasing tendency at different time points. Furthermore,liver and spleen shear wave velocity was higher in the unfavorable prognosis group,compared with the favorable prognosis group; the differences were statistically significant(P < 0.05). The prognosis of patients with portal hypertension was significantly affected by spleen hardness at the 3^(rd) month after treatment [relative risk(RR) = 3.481]. At the 9^(th) month after treatment,the prognosis was affected by liver hardness(RR = 5.241) and spleen hardness(RR = 7.829). The differences between these two groups were statistically significant(P < 0.05). The ROC analysis revealed that the area under the curve(AUC) of spleen hardness at the 3^(rd) month after treatment was 0.644,while the AUCs of liver and spleen hardness at the 9^(th) month were 0.579 and 0.776,respectively. These might predict the prognosis of patients with portal hypertension.CONCLUSION Spleen hardness at the 3^(rd) month and liver and spleen shear wave velocity at the 9^(th) month may be used to assess the prognosis of patients with portal hypertension. This is hoped to be used as an indicator of predicting the prognosis of patients with portal hypertension.

Successful treatment of hypovascular advanced hepatocellular carcinoma with lipiodol-targetting intervention radiology

We report a case of hypovascular advanced hepa-tocellular carcinoma (HCC) successfully treated with a novel combination therapy of percutaneous ethanol-lipiodol injection (PELI) and intervention radiology (IVR),lipiodol-targetting IVR (Lipi-IVR). The present case had a hypovascular HCC (3 cm in diameter) located in the S6 region of the liver. Although the tumor was not detectable at all by both of early and late phase of helical dynamic computed tomography (CT),it could be detected by ultrasonography (US) as a low echoic space occupying lesion (SOL) beside the gallbladder and right kidney. Serum levels of alpha fetoprotein (AFP) and AFP-L3 were extremely high. Combination therapy of PELI,firstly reported in our department,and IVR (PELI and IVR,lipiodol-targetting IVR) was performed twice for the treatment. PELI could effectively visualize the location of the tumor for IVR treatment and show the presence of a thin blood vessel branching from the right hepatic artery flowing into the lipiodol deposit. After treatment,the serum levels of AFP and AFP-L3 were rapidly decreased to normal and maintained for more than eight months. Thus,this case expressing the tremendous effect might give us insight into the effectiveness of the novel combination therapy of PELI and IVR for the treatment of hypovascular HCC.

Study on radon release of intact rocks during direct shear

Radon is a polluting and radioactive gas released by rock fracture. Shear fracture is widely developed in surrounding rock mass of deep engineering. Nevertheless, the correlation between radon release and the shear fracture is undefined. In this study, the intact Jinping marble and Baihetan basalt were adopted as samples. Based on radionuclide content analysis, the intrinsic characteristics of radon emission were analyzed. Then a direct shear testing system was designed to synchronously measure radon release during rock fracture. The direct shear tests were carried out under different normal stresses. The relationship between shear fracture process and cumulative radon concentration was explored. The results indicated that radon release varied with the increase of shear displacement under the same normal stress. The general pattern showed a slight increase and fell in the initial loading phase, then increased rapidly to the peak release approximately corresponding to the peak of shear stress, and finally decreased to a stable level with the development of shear displacement after sample failure. The initial and peak radon concentrations increased linearly with the increase of normal stress. The same trend was found in shear failure surface area and cumulative radon concentration according to the rise angle(RA) value-average frequency(AF) distribution.

Acoustic emission characteristics and stress release rate of coal samples in different dynamic destruction time

Considering the importance of the prediction of rock burst disasters, and in order to grasp the law of acoustic emission(AE) of coal samples in different dynamic destruction time, the SH-II AE monitoring system was adopted to monitor the failure process of coal samples. The study of the change rule of the AE numbers, energy, ‘b' value and spectrum in the micro crack propagation process of the coal samples shows that as dynamic damage time went by, AE presented high-energy counts and the accumulated counts increased during the compression phase. The AE energy and cumulative counts increased during the elastic stage. The AE blank area increased gradually and the blank lines were more and more obvious in the molding stage. The AE counts and energy showed a trend of decrease in the residual damage phase.AE ‘b' values gradually became sparse, and the large scale cracks percentage compared with micro cracks decreased and the degree of damage decreased. The AE frequency spectrum peak went from the residual damage phase to the molding phase, and finally it was nearly stable, besides the bandwidth of the main frequency is gradually narrowed. Also, the frequency peak changed from single peak frequency to bi-peak frequency and to the single peak frequency. Uniaxial compressive strength is more sensitive than the elastic modulus to dynamic damage time.

Application of three dimensional conformal radiation therapy combined with high-intensity focused ultrasound for prostate cancer

Objective:Prostate cancer is a form of cancer that develops in the prostate,a gland in the male reproductive system.Prostate cancer tends to develop in men over the age of fifty;it is one of the most prevalent types of cancer in men.This article introduced a new method of prostate cancer treatment with the combination of three dimensional conformal radiation therapy (3D-CRT) and high-intensity focused ultrasound (HIFU),its efficacy was evaluated.Methods:From January 2004 to December 2009,95 patients were diagnosed with prostate cancer,among them,48 patients were received combined therapy with total irradiation of TD 60 Gy/30 Fx and 5 fractions of HIFU treatment,while 47 patients were received with pure 3D-CRT with total irradiation of TD (66-72) Gy/(33-36) Fx.Various indicators were evaluated,such as the local control rate and distant metastasis rate,the changes in blood PSA and fPSA,changes in T-lymphocyte subsets and NK cells,as well as acute adverse reaction of normal tissue.Results:The local response rate difference between the two groups had statistical significance (P < 0.05);the changes in blood PSA and fPSA were significant (P < 0.05);CD3+,CD4+,CD8+,CD4+/CD8+ and NK cells of the combined group increased obviously (P < 0.01),while the latter group had no increase (P > 0.05);the combined group had lower blood cells reduction and II-level acute adverse reaction of rectum,bladder and caput humeri than the pure group,but the II-level acute adverse reaction of urogenital canal in the combined group was higher (P < 0.05).Conclusion:The combined therapy with 3D-CRT and HIFU is a good way for the treatment of aged-related prostate cancer.It can ease the symptoms,control the disease and lengthen the survival time.

用物理学原理看歌唱的学习环境

不同环境下歌唱者会对歌唱声音产生不同的感受。本文着重阐述了如何以物理学的原理去理解这些不同的感受，用正确的方法去处理，建立新的声音调整理念，进而使歌唱达到最佳效果。

Super-Planckian thermal radiation enabled by hyperbolic surface phonon polaritons

Excitation of surface resonance modes and presence of resonance-free hyperbolic modes are two common ways to enhance the near-field radiative energy transport, which can find wide applications in noncontact thermal management and energy harvesting.Here, we identify another way to achieve the super-Planckian thermal radiation via hyperbolic surface phonon polaritons(HSPhPs). Based on the fluctuation-dissipation theory, the near-field radiative heat flux between bulk hexagonal boron nitride(hBN) planes with the optical axis perpendicular to the radiative energy flow can be 120 times as large as the blackbody limit for a gap distance of 20 nm. When the film thickness is reduced to 10 nm, the radiative heat flux is found to increase by 26.3%.The underlying mechanism is attributed to the coupling of Type I HSPhPs inside the anisotropic hBN film, which improves the energy transmission coefficient over a broad wavevector space especially for waves with extremely high wavevectors. This work helps to deepen the understanding of near-field radiation between natural hyperbolic materials, and opens a new route to enhance the near-field thermal radiation.

Fiber Laser Sensor Based on a Phase-Shifted Chirped Grating for Acoustic Sensing of Partial Discharges

Acoustic emission monitoring is often used in the diagnosis of electrical and mechanical incipient faults in the high voltage apparatus. Partial discharges are a major source of insulation failure in electric power transformers, and the differentiation from other sources of acoustic emission is of the utmost importance. This paper reports the development of a new sensor concept - a fiber laser sensor based on a phase-shifted chirped fiber grating - for the acoustic emission detection of incipient faults in oil-filled power transformers. These sensors can be placed in the inner surface of the transformer tank wall, not affecting the insulation integrity of the structure and improving fault detection and location. The performance of the sensing head is characterized and compared for different surrounding media： air, water, and oil. The results obtained indicate the feasibility of this sensing approach for the industrial development of practical solutions.