相干源二维波达方向估计

本文分析了平面阵接收信号的协方差矩阵，发现它可分解为一个广义对称矩阵与一个非广义对称矩阵之和，利用信号协方差矩阵的这一结构特征，重点研究了相干源二维波达方向（DOA）估计．该方法通过构造一个差矩阵，求出其本特征值对应的任一特征向量，利用谱函数估计相干源二维DOA．简要分析了二维DOA估计的分维处理。     

The lattice dynamics of the Fe(tpa) (NCS)2 complex : light-induced excited spin state trapping effect

A light-induced excited spin state trapping (LIESST) experiment for a thermal gradual spin crossover complex, Fetris (2-pyridylmethyl) amine(NCS)2 or Fe(tpa) (NCS)2, was attempted for the first time. The high spin (HS) state after light inducement stayed metastable over a period of days without relaxation at 10 K. Intersystem relaxation from a high to a low spin (LS) complex occurred at 50 K after bleaching at 10 K. Investigation of the Mossbauer spectra of the LIESST and relaxation experiment indicated that the Debye–Waller factor was a correlation parameter of the HS fraction and that the co-operative effect played a role in the relaxation process for such a solid compound. This revised version was published online in November 2006 with corrections to the Cover Date.     

Propagation characteristics of a heaviside absorbing layer for TLM

The perfectly matched layer for use with the finite-difference time-domain method is adapted to our transmission-line matrix simulation as what we call a heaviside absorbing layer (HAL). It is shown that the reflection coefficient for the wave incident on a HAL is less than that of the wave incident on a matched-load termination at all angles of incidence. Furthermore, the dispersion relation of a transmission-line matrix mesh of a symmetrical condensed node with both electric and magnetic loss stubs is derived. It provides guidance on how to choose the losses of HAL and other simulation parameters properly     

STRESS INTENSITY FACTORS AND WEIGHT FUNCTIONS FOR SEMI-ELLIPTICAL SURFACE CRACKS IN FINITE-THICKNESS PLATES UNDER TWO-DIMENSIONAL STRESS DISTRIBUTION

Abstract— A Fourier series approach is proposed to calculate stress intensity factors using weight functions for semi-elliptical surface cracks in flat plates subjected to two-dimensional stress distributions. The weight functions were derived from reference stress intensity factors obtained by three-dimensional finite element analyses. The close form weight functions derived are suitable for the calculation of stress intensity factors for semi-elliptical surface cracks in flat plates under two-dimensional stress distributions with the crack aspect ratio in the range of 0.1 ≤ a/c ≤ 1 and relative depth in the range of 0 ≤ a/t ≤ 0.8. Solutions were verified using several two-dimensional non-linear stress distributions; the maximum difference being 6%.     

Inhibitory effect of ganciclovir on the HSV1-tk positive subcutaneous tumors transplanted with human ovarian cancer in nude mice

OBJECTIVE: To investigate the inhibitory effect in vivo of ganciclovir (GCV) on the growth of human ovarian cancer cells (AO) transducted with the thymidine kinase gene of herpes simplex virus I type (HSV1-tk). METHODS: Tumors were induced in nude mice by subcutaneous injection of AO cells and AO cells carried with HSV1-tk gene from China strain (AO/HSV1-tk cells). When the growing tumors were visible, GCV was injected daily into the peritoneum of the nude mice. RESULTS: The average weights of survived AO/HSV1-tkc tumors and AO tumors treated with GCV were 0.087 +/- 0.036 g and 0.661 +/- 0.260 g respectively. Most of the survived AO/HSV1-tkc cells treated with GCV were characterized by hypertrophy and necrosis, but their nuclear chromatins predominantely took the forms of heterchromatins. CONCLUSIONS: GCV could effectively inhibit the growth of HSV1-tk positive human ovarian cancer cells in vivo, but the nuclei of the survival tumor cells appeared to proliferate actively. As the same results of in vitro experiments, this may suggest that HSV1-tk/GCV gene therapeutic system might be combined with S-phase chemotherapy to increase the long-term effect.     

On the reliability of Landsat TM for estimating forest variables byregression techniques: a methodological analysis

In order to build models that relate thematic mapper (TM) imagery to field forest variables, several regression techniques, such as the ones based on the Mallows' C_p and the adjusted R² statistics, were applied. Nevertheless, although the best created models had good fittings (R²>0.65) apparently supported by a clear statistical significance (p<0.0001), later trials tested with additional plots showed that these models were, in fact, nonrobust models (models with very low-predictive capabilities). Two factors were pointed out as causes of these inconsistencies between predicted and observed values: a relatively small number of available field plots and a relatively high number of possible independent variables. Actually, different trials suggested much lower fittings for the expected “really” predictive models. Some restrictions of TM satellite data, such as its radiometric, spectral, and spatial limitations, together with restrictions arising from gathering and processing of field data, might have led to these poor relations. This study shows the need for guarantees stronger than the usual ones before concluding that there is a clear possibility of using satellite information to estimate forest parameters by means of regression techniques     

Suppressive effect of corticosteroids on the gene expression of interleukin-5 and eosinophil activation in asthmatics

Although cortico steroids are effective anti-inflammatory agents in ameliorating asthma symptoms and bronchial hperreactivity, their mechanism of action is unknown. Interleukin (IL)-5 is known to play a key role in regulating eosinophil proliferation and activation. Therefore, we examined the changes of IL-5 mRNA expressions in PBMC semi-quantitatively with RT-PCR as well as serum ECP levels and MCH-PC20 values in asthmatics before and after being treated with corticosteroids. The results revealed that there were significant decrease in the level of IL-5 mRNA and serum ECP concentration after therapy (P < 0.05) and there was remarkable improvement in the values of MCH-PC20 and FEV1% (P < 0.05). It was also found that the changes of serum ECP levels or MCH-PC20 values were accompanied by a reduction in IL-5 mRNA expression (r = 0.5426 or 0.4857, P < 0.05). These results suggested that the therapeutic effects of corticosteroids in asthma may result from modulation of IL-5 gene expression with consequent inhibition of eosinophil activation.