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991.
����������Դ���ƽ����ִ�����Ӧ�����о� 总被引:3,自引:0,他引:3
?о???1996??2005??????????52????С?????????????6????????????????????????????????????????????????????????????P???????NW????300??320???????У??????????????????????????????????????????????????????????????????????????????????仯?????????????????????????????????????NNW????????????總?????????????NWW????EW???? 相似文献
992.
The purpose of the present study is to investigate the performance and three-dimensional flow fields in a water-jet pump. TASCflow is employed to simulate the rotator-stator coupling flow field. A standard k-ε turbulence model combined with standard wall functions is used. In order to investigate the effect of a rear stator on flow fields, the flows in two water-jet pumps with and without a rear stator are studied. Computational fluid dynamics (CFD)-predicted overall performances are in good agreement with the experimental results. Then the flow fields, such as the pressure distribution on the blade surfaces, and the axial and tangential velocity distribution, especially the radial loading distribution, are investigated at different flow rates. In addition, the effects of a rear stator and different spacings between the rotor and the stator on the overall performance and the flow fields of the water-jet pump are also investigated. 相似文献
993.
994.
利用LINUX操作系统下的进程通讯(IPC)技术将中尺度大气模式MM5(V3)与第三代海浪模式WW3进行双向耦合,建立考虑大气-海浪相互作用的风浪耦合模式,在耦合模式中引入3种海表粗糙度参数化方案,通过对一次热带气旋过程的模拟,研究大气-海浪相互作用对热带气旋系统的影响及耦合模式对海表粗糙度参数化方案的敏感性。结果表明:LINUX系统下的进程通讯技术可以方便有效地实现大气和海浪模式的双向耦合,模式运行稳定;耦合模式能够较好的模拟热带气旋的发展和演变过程及其影响下海浪场的分布和演变,模拟结果对海表粗糙度参数化方案较敏感;海浪的反馈作用同时影响了海气间的动力和热力作用过程,不同的海表粗糙度参数化方案下,海浪对两种作用过程不同的影响程度决定了其对气旋系统强度的影响。 相似文献
995.
The scattering of water waves by bottom-mounted vertical circular cylinders is solved by using the null-field integral equations in conjunction with degenerate kernels and Fourier series to avoid calculating the Cauchy and Hadamard principal values. In the implementation, the null-field point can be exactly located on the real boundary owing to the introduction of degenerate kernels for fundamental solutions. An adaptive observer system of polar coordinates is considered to fully employ the properties of degenerate kernels. For the hypersingular equation, vector decomposition for the radial and tangential gradients is carefully considered. This method can be seen as a semi-analytical approach since errors attribute from the truncation of Fourier series. Neither hypersingularity in the Burton and Miller approach nor the CHIEF concept was required to deal with the problem of irregular frequencies. Five advantages of free of calculating principal value, well-posed algebraic system, convergence rate of exponential order, meshfree and elimination of boundary-layer effect, are achieved by using the present approach. Numerical results are given for the forces and free-surface elevation around the circular boundaries. Also, the near-trapped behavior arisen from the physical resonance is detected. A general-purpose program for water wave impinging several circular cylinders with arbitrary number, radii, and positions was developed. Several examples of water wave structure interaction by vertical circular cylinders were demonstrated to see the validity of the present formulation. 相似文献
996.
Distribution and sources of organochlorine pesticides in water and sediments from Daliao River estuary of Liaodong Bay,Bohai Sea (China) 总被引:1,自引:0,他引:1
The levels of 19 kinds of organochlorine pesticides (OCPs) in the aqueous phase, suspended particulate matter (SPM), pore water and sediments from Daliao River estuary of Liaodong Bay (Bohai Sea) in northeast China were investigated to evaluate their potential pollution risks. The total OCPs concentrations in the aqueous phase, SPM, pore water and sediments were 3.7–30.1 ng l−1, 4.6–52.6 ng l−1, 157–830 ng l−1 and 2.1–21.3 ng g−1 dry weight, respectively. The concentrations of OCPs, in the Daliao River estuary, are in the mid-range, as compared to those reported in other estuaries worldwide. The distribution of HCHs and DDTs were different indicating different contamination sources. Lindane is the main type of HCH and continuing use in northeast China of ‘pure’ HCH (lindane) rather than technical HCH accounts for the source. The ratios of (DDE + DDD)/DDT in the samples indicate no recent inputs of these chemicals to the estuary. 相似文献
997.
Based on the sequence data of the nuclear ribosomal DNA internal transcribed spacer (ITS) 1, 5.8 S, and ITS 2, the molecular
phylogeny was analyzed on Ulvaceae species collected from Qingdao coasts in summer of 2007, including 15 attached Ulva and Enteromorpha samples from 10 locations and 10 free-floating Enteromorpha samples from seven locations. The result supported the monophyly of all free-floating Enteromorpha samples, implying the unialgal composition of the free-floating Enteromorpha, and the attached Ulvaceae species from Qingdao coasts were grouped into other five clades, suggesting that they were not
the biogeographic origin of the free-floating Enteromorpha in that season.
Supported by NSFC (40506030); the Innovative Key Project of the Chinese Academy of Sciences (KZCX2-YW-209); Science & Technology
Project of Qingdao City (06-2-2-12-JCH) 相似文献
998.
????1992??11???2007??5?μ???????????????????????????仯???????????????1???????24~42???μ???????Я???????????ENSO?????2??SLA_2442?????????????????????????????????????????????????????????????????3?????????У????????????SLA_2442?????????·??????O???Σ??????????????,??γ????????λ??????9.86??N??8??S?????? 相似文献
999.
Comparison of ecophysiological characteristics between introduced and indigenous mangrove species in China 总被引:2,自引:1,他引:1
Luzhen Chen Nora F.Y. Tam Jianhui Huang Xueqin Zeng Xiangli Meng Cairong Zhong Yuk-shan Wong Guanghui Lin 《Estuarine, Coastal and Shelf Science》2008,79(4):644-652
Due to its rapid growth, the introduced mangrove species Sonneratia apetala from Bangladesh has been widely used in mangrove restoration in southeastern China since 1985. As an indigenous mangrove species in Hainan, China, Sonneratia caseolaris was also planted in Guangdong Province for afforestation purposes. Both species have developed well in their new habitats, but their ecophysiological differences with the native mangrove species have not been studied. In this study, leaf gas exchange, water and nitrogen use efficiencies of two Sonneratia species were compared with those of selected native mangrove species (Avicennia marina, Aegiceras corniculatum, Kandelia candel, and Excoecaria agallocha) in Hainan and Shenzhen. The introduced S. apetala maintained lower carbon assimilation rate (A) and photosynthetic nitrogen use efficiency (PNUE) than the indigenous S. caseolaris. In Shenzhen, the two introduced Sonneratia had comparable photosynthetic rates and water use efficiency (WUE) with the native mangrove species, except that PNUE in S. caseolaris was significantly higher than in the native mangrove species. The two Sonneratia species showed significant overlap in PNUE and long-term WUE. Photosynthetic parameters derived from leaf photosynthetic light–response curves and A–Ci curves also suggested lower carbon assimilation capacities for the introduced Sonneratia than for the native mangrove species in both study sites. The lower light compensation point (LCP) of two introduced Sonneratia in both study sites also indicated a better adaptation to a low light regime than the native mangrove species. The results of photosynthetic capacities indicated that the introduced mangrove species have little competitive advantage over local native mangrove species in their respective new habitats. 相似文献
1000.