10?30 GHz monolithic GaAs travelling-wave divider/combiner

A four-way monolithic GaAs travelling-wave power divider/combiner has been designed, fabricated and evaluated. With a design centre frequency of 20 GHz, a bandwidth of from 10 GHz to 30 GHz has been measured. The insertion loss per dividing or combining action is less than 0.5 dB, with isolation between ports no worse than 20 dB. The input/output VSWRs are better than 2:1 across the same band. This divider/combiner can readily be used with monolithic GaAs power FET amplifiers to produce a several-fold increase in output powers over the 10 to 30 GHz frequency range.     

Modeling of Temperature–Frequency Correlation Using Combined Principal Component Analysis and Support Vector Regression Technique

A good understanding of environmental effects on structural modal properties is essential for reliable performance of vibration-based damage diagnosis methods. In this paper, a method of combining principal component analysis (PCA) and support vector regression (SVR) technique is proposed for modeling temperature-caused variability of modal frequencies for structures instrumented with long-term monitoring systems. PCA is first applied to extract principal components from the measured temperatures for dimensionality reduction. The predominant feature vectors in conjunction with the measured modal frequencies are then fed into a support vector algorithm to formulate regression models that may take into account thermal inertia effect. The research is focused on proper selection of the hyperparameters to obtain SVR models with good generalization performance. A grid search method with cross validation and a heuristic method are utilized for determining the optimal values of SVR hyperparameters. The proposed method is compared with the method directly using measurement data to train SVR models and the multivariate linear regression (MLR) method through the use of long-term measurement data from a cable-stayed bridge. It is shown that PCA-compressed features make the training and validation of SVR models more efficient in both model accuracy and computational costs, and the formulated SVR model performs much better than the MLR model in generalization performance. When continuously measured data is available, the SVR model formulated taking into account thermal inertia effect can achieve more accurate prediction than that without considering thermal inertia effect.     

Peripheral nerve injury as a complication from orthopedic operation

We report a case of pulmonary carcinosarcoma. Surgery is required for this rare mixed type, biphasic tumor. It is generally considered to be a malignant formation issuing from a single cell line but with a two-way differentiation into epithelial and conjunctive components. There is a differentiation continuum between spindle-cell carcinomas (also called monophasic sarcomatoid carcinoma) and carcinosarcoma (or biphasic sarcomatoid carcinoma) leading to debate concerning the immunohistochemical and ultrastructural features.     

聚苯醚磺酸锂／共聚醚复合物的离子导电性研究

合成了３种不同磺化度的聚苯醚磺酸锂（ＳＰＰＯＬｉ）与Ｐ（ＭＥＯ１６－ＡＭ）／ＳＰＰＯＬｉ复合物。研究了复合物的离子导电性与磺化度，组成比及增塑剂含量的关系。含４０％（ｍａｓｓ）增塑剂的复合物具有单离子导电特征，锂离子迁移数高达０．９７，室温电导率达２×１０－５Ｓ／ｃｍ。     

Hydrogen peroxide in exhaled air is increased in stable asthmatic children

Exhaled air condensate provides a noninvasive means of obtaining samples from the lower respiratory tract. Hydrogen peroxide (H2O2) in exhaled air has been proposed as a marker of airway inflammation. We hypothesized that in stable asthmatic children the H2O2 concentration in exhaled air condensate may be elevated as a result of airway inflammation. In a cross-sectional study, 66 allergic asthmatic children (of whom, 41 were treated with inhaled steroids) and 21 healthy controls exhaled through a cold trap. The resulting condensate was examined fluorimetrically for the presence of H2O2. All subjects were clinically stable, nonsmokers, without infection. The median H2O2 level in the exhaled air condensate of the asthmatic patients was significantly higher than in healthy controls (0.60 and 0.15 micromol, respectively; p<0.05), largely because of high values in the stable asthmatic children who did not use anti-inflammatory treatment (0.8 micromol; p<0.01 compared to controls). We conclude that hydrogen peroxide is elevated in exhaled air condensate of children with stable asthma, and may reflect airway inflammation.     

使用混合杆柱时抽油泵柱塞的超冲程

任何抽油杆柱在理论上都可能产生超冲程，只是大小不同而已。超冲程的存在，使泵柱塞的有效冲程增大，甚至会大于光杆冲程。首次提出了抽油泵柱塞相对超冲程和绝对超冲程的概念，这将有助于正确认识玻璃钢抽油杆的作用和玻璃钢抽油杆的推广使用。将抽油杆柱简化成上端受光杆的激振位移、下端带有集中质量的弹簧－质量力学模型，建立了抽油杆柱纵向振动的偏微分方程和边界条件，然后用固有函数法求解方程，得出了抽油泵柱塞超冲程的无穷级数解析计算式。     

Histology of rat small bowel transplants: cyclosporine A ameliorates features of rejection including apoptosis and ganglion cell reduction

The spectrum of photoaging in human skin shows a recognizable progression from subtle to profound, reflecting the various anatomic and structural changes that appear with aging skin. Qualification and quantification of these changes on both the macroscopic and microscopic levels enable the physician to select and evaluate appropriate therapeutic approaches to the problem of chronic solar damage. Comparative studies remain to be done that will further refine our abilities to match the right solutions to the recognized problems.