激光谐振腔自再现模的波型特征

本文用光传输矩阵理论给出分析激光光腔模式波型特性统一处理方法 .导出激光谐振腔自再现模的波型函数 .讨论了在各类激光谐振腔中激光束的波型特征 .

制度变迁与制度效率的波型特征的经济分析

由于制度效率存在递减规律,这就意味着当制度效率降低到一定程度时,制度的变迁是必要的。虽然制度具有内在的自然演进与变迁的动因,但制度变迁更重要的是在人为设计下进行。因为人为的制度安排或制度变迁更能及时地避免既有制度的效率损失,也可以获得新制度的更高的效率,从而实现社会各项资源在较高水平上的优化配置。

红庆梁矿井副立井大罐笼提升系统振动实验研究

为提高副立井提升系统的安全性能,文章针对红庆梁矿井副立井特大罐笼提升系统(每次提升300人)进行振动了实验研究,对提升机、电机、导向轮以及罐笼进行了振动测试和数据采集分析。经分析研究确定提升机、电机、导向轮均运行良好,但罐笼在运行速度为2. 9m/s处发生了共振。通过实验研究找出罐笼共振频率约为39Hz,并给出了解决罐笼共振的技术措施。

一次飑线天气过程的综合分析和数值模拟

2006年6月22日上海市经历了一次飑线天气过程,严重影响了虹桥、浦东机场的飞机飞行安全。通过多种气象资料综合分析了此次天气过程。分析表明,中低空辐合线与副高边缘的高能水汽输送带相配合,为MCS的发生提供了有利的环境条件,高空槽导致MCS发展和加强,地面锋面和有利的垂直层结使得MCS中的雷暴群发展为飑线。多普勒雷达回波中呈明显的线状回波的波型特征(Line echo wave pattern,LEWP),有弓状回波存在。在雷达速度PPI上观测到在大范围正速度区中有一个小的负速度区,这是MARC(mid-altitude radial convergence)结构。MM5数值模拟显示在强对流的两侧分别有气旋和反气旋性结构存在,并且在回波带后侧有非常明显的后向入流,这与Fujita提出的弓形回波的概念模型一致。

钢板探伤缺陷的分析

文章根据多年的实践经验,总结了几种钢板常见探伤缺陷的波型特征,分析了缺陷的成因,并提出了解决探伤问题的工艺措施。

An approach to estimate tidal dissipation with single-point high-frequency ground wave radar data

Using the single-point ground wave （GW） radar data at Shensi Station and the water level data at three stations （Shengsi, Luchaogang and Daishan）, the authors obtained the flow vectors from the radial velocity of GW radar observation, and calculate four sub-tidal harmonic constants （O1, K1, M2 and S2）. The tidal characteristics derived from the GW radar dataset agreed well with those from the tidal gauge data. The authors also analyzed the tidal energy flux and tidal energy dissipation rate. There was a good relationship between the tidal energy dissipation rate and topography. The study showed a good way to calculate tidal energy dissipation rate using GW radar data.

Isogeometric analysis for elliptical waveguide eigenvalue problems

The cutoff wavenumbers of elliptical waveguides were calculated by using isogeomtric analysis method （IGA）. With NURBS basis functions in IGA, the computational model was consistent with geometric model imported from CAD system. The field variable （longitudinal electric/magnetic field） was constructed by the same NURBS basis functions as the representation of geometric model. In the refinement procedure used to get a more accurate solution, communication with original CAD system is unnecessary and the geometric shape is kept unchanged. The Helrnholtz equation is weakened to a set of general eigenvalue equation by virtual work principal with diseretized degree-of-freedom on control points. Elliptical waveguides with three typical eccentricities, 0.1, 0.5 and 0.9, are calculated by IGA with different size mesh. The first four cutoff wavenumbers are obtained even in coarse mesh and the RMS of first 25 cutoff wavenumbers has much more swift convergence rate with decreasing the mesh size than traditional FEM. The accuracy and robustness of the proposed method are validated by elliptical waveguides, and also the method can be applied to waveguides with arbitrary cross sections.

Hydrodynamic Performance of Multiple-Row Slotted Breakwaters

This study examines the hydrodynamic performance of multiple-row vertical slotted breakwaters. We developed a mathematical model based on an eigenfunction expansion method and a least squares technique for Stokes second-order waves. The numerical results obtained for limiting cases of double-row and triple-row walls are in good agreement with results of previous studies and experimental results. Comparisons with experimental measurements of the reflection, transmission, and dissipation coefficients （CR, Cr, and CE） for double-row walls show that the proposed mathematical model adequately reproduces most of the important features. We found that for double-row walls, the CR increases with increasing wave number, kd, and with a decreasing permeable wall part, din. The Cr follows the opposite trend. The CE slowly increases with an increasing kd for lower kd values, reaches a maximum, and then decreases again. In addition, an increasing porosity of dm would significantly decrease the CR while increasing the Cr. At lower values of kd, a decreasing porosity increases the CE, but for high values of kd, a decreasing porosity reduces the Ce. The numerical results indicate that, for triple-row walls, the effect of the arrangement of the chamber widths on hydrodynamic characteristics is not significant, except when kd〈0.5 Double-row slotted breakwaters may exhibit a good wave-absorbing performance at kd〉0.5, where by the horizontal wave force may be smaller than that of a single wall. On the other hand, the difference between double-row and triple-row vertical slotted breakwaters is marginal.

Two Types of Arctic Oscillation and Their Associated Dynamic Features

In this paper,the dynamical evolutions of two types of Arctic Oscillation (AO),the stratospheric (S) and tropospheric (T) types,have been investigated on an intermediate time scale in terms of transient eddy feedback forcing and three-dimensional Rossby wave propagation.S-Type (T-type) events are characterized by an anomalous stratospheric polar vortex that is in phase (out of phase) with its tropospheric counterpart.Approximately onethird of AO events,both positive and negative,are T-type events.For the positive phase of a T-type event,the formation and maintenance of stratospheric positive anomalies over the polar cap are associated with an upward propagation of Rossby wave packets originating from the near-tropopause altitude over northeastern Asia.However,such upward propagating features are not found for S-type events.In the troposphere,transient eddy feedback forcing is primarily responsible for the meridional seesaw structure of both the S-and T-type events,with an additional contribution from Rossby wave propagation.

Characteristics of blood glucose excursions in type 2 diabetes mellitus patients with three different Traditional Chinese Medicine syndromes

OBJECTIVE:To explore the characteristics of blood glucose excursions of type 2 diabetes mellitus patients with three different Traditional Chinese Medicine(TCM) syndromes.METHODS:One hundred and nine patients with type 2 diabetes mellitus were recruited from the Department of Endocrinology and the Department of TCM of the Sixth People's Hospital affiliated to Shanghai Jiao Tong University.Subjects were divided into three groups according to TCM syndrome:intrinsic Damp(n- 42),Yin deficiency and internal Heat(n = 25),and Qi and Yin deficiency(n- 42).Subcutaneous interstitial glucose was monitored with a continuous glucose monitoring system for 3consecutive days to investigate the glycemic profile in each group.Plasma C-peptide levels were measured,and an arginine test was taken in 10 patients randomly selected from each group.Glucose data and glycemic variability were analyzed to investigate the differences among the groups.The change in C-peptide levels and the results from arginine trial were used to evaluate β cell function.RESULTS:Indicators reflecting blood glucose level were the highest in subjects with Yin deficiency and internal Heat syndrome,and parameters reflecting glycemic variability were the lowest in those with Qi and Yin deficiency syndrome.The change in C-peptide levels showed that subjects with Qi and Yin deficiency syndrome had the best βcell function among the three groups;this was confirmed by the arginine trial.CONCLUSION:Patients with Qi and Yin deficiency syndrome had a more stable blood glucose profile,as glycemic variability was higher in those with intrinsic Damp syndrome and those with Yin deficiency and internal Heat syndrome.