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931.
Journal of Oceanology and Limnology - Kuwait’s shrimp fishery presents typical tropical shrimp fishery characteristics with highly variable recruitment, fast growth and strong seasonal... 相似文献
932.
Guo-qing Chen Run-qiu Huang Feng-shou Zhang Zhen-fei Zhu Yu-chuan Shi Jian-chao Wang 《山地科学学报》2018,15(3):672-684
A new method, the dynamic reduction method (DRM) combined with the strain-softening method, was applied to evaluate the possible slip surface of a highly heterogeneous rock slope of the Dagangshan hydropower station in Southwest China. In DRM, only the strength of the failure elements is reduced and the softening reduction factor K is adopted to calculate the strength parameters. The simulation results calculated by DRM show that the further slip surface on the right slope of the Dagangshan hydropower station is limited in the middle part of the slope, while both SRM (strength reduction method) and LEM (limit equilibrium method) predict a failure surface which extends upper and longer. The observations and analysis from the three recorded sliding events indicate that the failure mode predicted by DRM is more likely the scenario. The results in this study illustrate that for highly heterogeneous slopes with geological discontinuities in different length scales, the proposed DRM can provide a reliable prediction of the location of the slip surface. 相似文献
933.
Type-I bursts (i.e. noise storms) are the earliest-known type of solar radio emission at the meter wavelength. They are believed to be excited by non-thermal energetic electrons accelerated in the corona. The underlying dynamic process and exact emission mechanism still remain unresolved. Here, with a combined analysis of extreme ultraviolet (EUV), radio and photospheric magnetic field data of unprecedented quality recorded during a type-I storm on 30 July 2011, we identify a good correlation between the radio bursts and the co-spatial EUV and magnetic activities. The EUV activities manifest themselves as three major brightening stripes above a region adjacent to a compact sunspot, while the magnetic field there presents multiple moving magnetic features (MMFs) with persistent coalescence or cancelation and a morphologically similar three-part distribution. We find that the type-I intensities are correlated with those of the EUV emissions at various wavelengths with a correlation coefficient of 0.7?–?0.8. In addition, in the region between the brightening EUV stripes and the radio sources there appear consistent dynamic motions with a series of bi-directional flows, suggesting ongoing small-scale reconnection there. Mainly based on the induced connection between the magnetic motion at the photosphere and the EUV and radio activities in the corona, we suggest that the observed type-I noise storms and the EUV brightening activities are the consequence of small-scale magnetic reconnection driven by MMFs. This is in support of the original proposal made by Bentley et al. (Solar Phys. 193, 227, 2000). 相似文献
934.
A new method for platform design, named parametric platform design method (PPDM), is presented in this paper in order to improve the mobile platform design efficiency. In this method, an integrated parametric system that fully considers the characteristics of the platform is developed, which significantly optimizes the design process with the top–bottom design concept. In the parametric system, the main geometric dimensions are taken as parameters, while the topology between the structure members, the function requirements and the safety requirements are converted into geometric constraints. By geometric constraint solving (GCS), a set of parameters that satisfy all the given constraints are determined, and then the design scheme is obtained by several core algorithms, such as parametric tank subdivision, 3D stability calculation, parametric structure design, FEM preprocessing, etc. The parametric method greatly increases the changeability and the reusability of the platform model, and concurrent design is well supported. As the model is driven by parameters, PPDM is an excellent method for optimization design. As a result, PPDM has incomparable advantages on the design efficiency over traditional methods. 相似文献
935.
研究了激发态质子转移(ESPT)分子2-(2'-羟基苯基)苯并噻唑(HBT)在不同极性溶剂中的光开关行为,探讨了溶剂极性对HBT分子光开光效应的影响.揭示了光开关脉冲信号的形成原因,建立了基于光诱导HBT分子激发态非线性折射效应的皮秒全光开关的理论模型.根据对时间响应函数的理论计算和实验结果分析,确定了光开关脉冲信号下降前沿和上升后沿的形成机理以及影响因素,并提出了增强光开关信号下降前沿的关断深度,提升上升后沿的恢复速度的有效途径和方法.本文工作为制成皮秒量级关断,微秒甚至纳秒量级重新打开的快速全光开关器 相似文献
936.
937.
938.
The improvement on the calculation of anti-Stokes energy transfer rate is studied in the present work. The additional proportion coefficient between Stokes and anti-Stokes light intensities of quantum Raman scattering theory as compared with the classical Raman theory is introduced to successfully describe the anti-Stokes energy transfer. The theoretical formula for the improvement on the calculation of anti-Stokes energy transfer rate is derived for the first time in this study. The correctness of introducing coefficient exp{ΔE / kT} from well-known Raman scatter theory is demonstrated also. Moreover, the experimental lifetime measurement in Er0.01YbxY1 - 0.01 - xVO4 crystal is performed to justify the validity of our important improvement in the original phonon-assisted energy transfer theory for the first time. 相似文献
939.
On the tangent bundle TSN-1 of the unit sphere SN-1, this paper reduces the coupled Burgers equations to two Neumann systems by using the nonlinearization of the Lax pair, whose Liouville integrability is displayed in the scheme of the r-matrix technique. Based on the Lax matrix of the Neumann systems, the Abel--Jacobi coordinates are appropriately chosen to straighten out the restricted Neumann flows on the complex torus, from which the new finite-gap solutions expressed by Riemann theta functions for the coupled Burgers equations are given in view of the Jacobi inversion. 相似文献
940.
We describe the microfabrication of 85Rb vapour cells using a glass-silicon anodic bonding technique and in situ chemical reaction between rubidium chloride and barium azide to produce Rb. Under controlled conditions, the pure metallic Rb drops and buffer gases were obtained in the cells with a few mm3 internal volumes during the cell sealing process. At an ambient temperature of 90 ℃ the optical absorption resonance of 85Rb D1 transition with proper broadening and the corresponding coherent population trapping (CPT) resonance, with a signal contrast of 1.5% and linewidth of about 1.7 kHz, have been detected. The sealing quality and the stability of the cells have also been demonstrated experimentally by using the helium leaking detection and the after-9-month optoelectronics measurement which shows a similar CPT signal as its original status. In addition, the physics package of chip-scale atomic clock (CSAC) based on the cell was realized. The measured frequency stability of the physics package can reach to 2.1×10-10 at one second when the cell was heated to 100 ℃ which proved that the cell has the quality to be used in portable and battery-operated devices. 相似文献