采用发声装置控制鱼的游向

最近研究出三种发声装置,以控制水电站附近鱼的游向。从发声装置的频率、振幅分析,新装置的适应性比以前大多数的类似装置有所提高,并对一些鱼类有驱赶或引诱作用。本文在这里介绍了这些装置的设计特性及现场试验结果。

游向雅典2004

2001年2月，19岁的南非游泳运动员娜塔莉遭遇了不幸的交通事故，左膝以下不得不截肢。然而仅三个月后，这位南非姑娘便又回到了游泳池中。

游向高原的鱼

水从高原由西向东流着，渤海口的一条鱼逆流而行。

灵魂在行走

每个人心中都有一条塞纳河,它把我们的一颗心分作两边:左岸住着我们的欲望、挣扎和所有的爱恨嗔怒;右岸是一方净土,住着我们内心的柔软与纯粹。不同的追求便有不同的选择,逐利者游向左岸,高尚者游向右岸。那么,你的追求游向了哪一岸呢?放眼现代社会,拜金主义横行,不知有多少人被利欲冲昏了头脑,迷失了自我,忘记追求内心的纯粹。

Influence of Tourists′ Environmental Tropisms on Their Attitudes to Tourism and Nature Conservation in Natural Tourist Destinations: A Case Study of Jiuzhaigou National Park in China

People′s environmental tropism has an effect on their understanding of tourism-nature relationship,and also influences their attitudes to natural resources utilization and environmental protection.Taking Jiuzhaigou National Park of China as a study case,the authors conducted some quantitative analyses with the tools of SPSS 16.0 and LISREL 8.7,to explore the influence of tourists′ environmental tropism on their attitudes to tourism and nature conservation in the natural tourist destination.Three hypotheses and the theoretic model of influences of tourists′ environmental tropism on their attitudes to tourism and nature conservation have been tested and accepted based on the Structural Equation Model analysis on survey data collected in Jiuzhaigou National Park of China.Some conclusions were drawn as follows: 1) tourists′ human-prioritized concept influences their cognition to tourism-nature relationship.This concept has a positive influence on their supportive attitudes to tourism,but a negative influence on their attitudes to nature conservation;2) tourists′ human-nature coordination concept has a positive influence on their supportive attitudes to both tourism and nature conservation,especially to the latter.This paper generally proves that human′s environmental tropism does have an influence on their attitudes to tourism and nature conservation in natural tourist destinations.

Impact of Tourists'Perceived Value on Behavioral Intention for Mega Events:Analysis of Inbound and Domestic Tourists at Shanghai World Expo

Based on the survey data for 2120 inbound and domestic tourists at the Shanghai World Expo,a structural equation model was constructed for the relationship among tourists' perceived value dimensions,behavioral intention and revisit intention.Additionally,the influence of tourists' perceived value dimensions on the behavioral intention and revisit intention was explored.The results show that the utilitarian value and enjoyment value significantly affect the inbound and domestic tourists' behavioral intention,while the convenience value and aesthetic value have no significant influence.The service value only significantly affects the domestic tourists' behavioral intention,and the aesthetic value only significantly affects the inbound tourists' behavioral intention.The utilitarian value,service value and enjoyment value significantly affect the inbound and domestic tourists' revisit intention,while the convenience value only significantly affects the domestic tourists' revisit intention.The utilitarian value is the primary factor affecting the inbound tourists' behavioral intention and revisit intention,and the perceived price has no significant effect on either inbound or domestic tourists' behavioral intention or revisit intention.The study explores the relationships between tourists' perceived value,behavioral intention and revisit intention,analyzes the divergence and causation,theoretically enriches the research field of tourism geography and behavioral geography,and has great practical significance to the sustainable development of mega events in China,including the further development of the Shanghai World Expo.

Reliability and sensitivity analyses of HPT blade-tip radial running clearance using multiply response surface model

To reasonably design the blade-tip radial running clearance(BTRRC) of high pressure turbine and improve the performance and reliability of gas turbine, the multi-object multi-discipline reliability sensitivity analysis of BTRRC was accomplished from a probabilistic prospective by considering nonlinear material attributes and dynamic loads. Firstly, multiply response surface model(MRSM) was proposed and the mathematical model of this method was established based on quadratic function. Secondly, the BTRRC was decomposed into three sub-components(turbine disk, blade and casing), and then the single response surface functions(SRSFs) of three structures were built in line with the basic idea of MRSM. Thirdly, the response surface function(MRSM) of BTRRC was reshaped by coordinating SRSFs. From the analysis, it is acquired to probabilistic distribution characteristics of input-output variables, failure probabilities of blade-tip clearance under different static blade-tip clearances δ and major factors impacting BTRRC. Considering the reliability and efficiency of gas turbine, δ=1.87 mm is an optimally acceptable option for rational BTRRC. Through the comparison of three analysis methods(Monte Carlo method, traditional response surface method and MRSM), the results show that MRSM has higher accuracy and higher efficiency in reliability sensitivity analysis of BTRRC. These strengths are likely to become more prominent with the increasing times of simulations. The present study offers an effective and promising approach for reliability sensitivity analysis and optimal design of complex dynamic assembly relationship.

Spectrum allocation game of directional transmission in multi-hop cognitive radio networks

The spectrum allocation for links in multi-hop cognitive radio networks is addressed.The links rent the vacant licensed bands offered by primary users for implementing directional transmission.To minimize the individual cost,the links share the licensed band and rental fee.An interference model for the directional transmission in cognitive radio networks is proposed to formulate the cooperative and dynamic behavior of the links using the theory of hedonic game,called spectrum allocation game.The game is proved to converge to the core stable state indicating that all links satisfy with their current conditions and do not deviate from their coalitions.Numerical results show that the game improves spectral efficiency and contributes to reducing the individual cost of the links.

Numerical Simulation of Multi-Directional Random Wave Transformation in a Yacht Port

This paper extends a prediction model for multi-directional random wave transformation based on an energy balance equation by Mase with the consideration of wave shoaling, refraction, diffraction, reflection and breaking. This numerical model is improved by 1) introducing Wen's frequency spectrum and Mitsuyasu's directional function, which are more suitable to the coastal area of China; 2) considering energy dissipation caused by bottom friction, which ensures more accurate results for large-scale and shallow water areas; 3) taking into account a non-linear dispersion relation. Predictions using the extended wave model are carried out to study the feasibility of constructing the Ai Hua yacht port in Qingdao, China, with a comparison between two port layouts in design. Wave fields inside the port for different incident wave directions, water levels and return periods are simulated, and then two kinds of parameters are calculated to evaluate the wave conditions for the two layouts. Analyses show that Layout I is better than Layout II. Calculation results also show that the harbor will be calm for different wave directions under the design water level. On the contrary, the wave conditions do not wholly meet the requirements of a yacht port for ship berthing under the extreme water level. For safety consideration, the elevation of the breakwater might need to be properly increased to prevent wave overtopping under such water level. The extended numerical simulation model may provide an effective approach to computing wave heights in a harbor.

Spatial and temporal variations of Synechococcus and picoeukaryotes in the Taiwan Strait,China

The size-fractionated phytoplankton biomass, and the spatial and temporal variations in abundance of Synechococcus (SYN) and picoeukaryotes (PEUK) were measured in the Taiwan Strait during three cruises (August 1997, February-March 1998, and August 1998). The results show that picophytoplankton and nanophytoplankton dominate the phytoplankton biomass, in average of 38% and 40%, respectively. SYN and PEUK varied over time in abundance and carbon biomass, greater in summer than in winter, in range of (7.70–209.2)×106 and (0.75–15.4)×106 cells/cm2 in the abundance, and 1.93–52.3 and 1.57–32.4 μgC/cm2 in the carbon biomass, for SYN and PEUK, respectively. The horizontal distributions of both groups were diurnal but heterogeneous in abundance, depending on the groups and layer of depths. Temperature is the key controlling factor for picophytoplankton distribution (especially in winter) in the Strait.

Market orientation for the hotel segment： The Portuguese case

In view of the importance of the hotel segment for the tourism and for the economy of countries such as Portugal, the objective of this study was to measure the level of orientation for the market of the largest hotel groups of Portugal. This investigation initially emphasized the importance of the marketing for the organizations, mainly the orientation for the market. After a brief explanation on the hotel segment in Portugal, an empirical study was presented, of quantitative, exploratory and traversal character, performed with the largest groups of 20 hotels of Portugal, using as an instrument of collection data, the traditional Markor scale （market orientation） adapted to the hotel sector. After analyzing the data, it was found in the investigated organizations that a good capacity to generate market information and response to the market, which formed two of the three constructs of Markor scale. However the results obtained with the construct of the dissemination of market information were below the expectations. It was possible to conclude that marketing professionals of the large hotel groups in Portugal are well oriented to the market, something not shared by other investigated departments of the hotels. So the current challenge for the main networks of hotels in Portugal is to improve the internal dissemination of information that marketing professionals gathered at the market.

Rejuvenating wood carving industry in Taiwan Sanyi： A perspective of strategic management

This research aimed at providing suggestions to rejuvenate the wood carving industry in Taiwan Sanyi. The authors conducted interviews with representative store keepers and sculptors to gain industrial insights, and applied the strategic matrix analysis developed by Dr. Seetoo to examine industrial conditions and formulate strategic suggestions for wood carving companies. The industry was found lack of market orientation, which was considered as the critical factor of the long term depression. However, a market of tourism for nostalgic and cultural experience started developing in the near area, providing opportunities for Sanyi wood carving industry to recover. The main suggestions the authors made are （1） restructuring the product scope to respond to the market, and （2） branding with resorts in near area.

挑战,成就更好的我

鱼儿挑战游向更浩瀚的大海,鸟儿挑战飞向更蔚蓝的天空,马儿挑战奔向更广袤的草原。我亦不例外,我挑战走向更精彩的未来,成就更好的自己。十五个春秋轮回,无数次挑战自我,有成功、有失败、有欢笑、有泪水,但没有放弃、没有退缩。【语言:病句,缺少主语。】升入初三后,我面临最大的一次挑战便是明年六月的中考。七张卷子,将决定未来的我将何去何从。

Analysis of the effect of regional lateral inflow on the flood peak of the Three Gorges Reservoir

The Three Gorges Region(TGR),located at the lower reach of the Upper Yangtze River Basin(UYRB) in China,suffers from heavy rainstorm frequently.The runoff generated from TGR composes an important part of the total flood at the famous Three Gorges Reservoir(TGRe).During the severe flood period in 1954,for example,the water from TGR accounted for up to 13.2% of the 30-days maximum flood volume of the UYRB.Considering the short and steep tributaries with rapid concentration,the regional lateral inflow(RLI) may induce more serious effect on the flood peak of the TGRe than the volume.However,hydrological data of the sparse gauge stations is too insufficient to evaluate the effect of RLI.This paper studied the impact by analyzing 880 flood events during 1956-2000.By comparing the observed hydrograph and simulated hydrograph with HEC-RAS software regarding no RLI,the effect of RLI on flood peak value and timing properties was identified and quantified.The variability of this effect among floods of different magnitudes was also analyzed.To evaluate the analysis uncertainty associated with the parameter of roughness coefficient,four sets of roughness coefficients from different research groups were employed in this study.The results showed that RLI contributes discharge of 3524 m3/s to flood peaks of the TGRe on average,with the contribution ratio of 15.9%.RLI contributes 12000 m3/s to the flood peaks larger than 50000 m3/s on average,with 25000 m3/s as its upper bound,while the contribution ratio can reach up to 50%,with an average of 20%.The variability of this effect is great among different events.Statistical analysis showed that to larger flood peak of the TGRe,RLI contributes more discharge with higher variability,and the contribution ratio and its variability are slightly larger,and events with higher contribution ratio occur more frequently.RLI can reshape the hydrograph,leading to earlier appearance of flood peak.This effect and its variability increase with the contribution ratio.This study has revealed that RLI plays an important role in large flood peak of the TGRe,which calls for more reliable flood forecasting methods to prolong the forecast lead time and improve the accuracy for the safety of the Three Gorges Dam and the protection of its lower reaches during severe flood disaster period.

A review on gyrotactic swimmers in turbulent flows

Many marine plankton species are motile and perform daily vertical migrations,traveling across water columns over distances of tens of meters.It is intriguing that these tiny and slow swimmers can travel in a certain direction within a turbulent environment.One way to do that is by exploiting gravitaxis,which is a form of taxis characterised by the directional movement of an organism in response to gravity.Many plankton species are able to generate a gravitational torque(e.g.,due to a nonuniform mass distribution)that reorients them upwards.However,the swimming direction is disturbed by the shearing motions and the velocity fluctuations that characterise oceanic turbulence:these can generate a viscous torque that may destabilize the swimmer.The directed locomotion resulting from the combination of gravitational and viscous torques in a flow is termed gyrotaxis,which is known to lead to a non-uniform spatial accumulation of swimmers in patches or layers.These phenomena depend strongly on the non-linear dynamics that originate from the fluid motions,and the study of gyrotactic swimmers in complex flows is attracting growing attention.Numerical simulations of the Navier-Stokes equations coupled with suitable models of gyrotactic swimmers have proven their capability to provide valuable insight into the dynamical and statistical properties of self-propelled organisms.In this paper,we review recent studies and key findings on gyrotactic swimmers in turbulent flows.First,we introduce the most recent results concerning the orientation and vertical migration of gyrotactic swimmers in isotropic turbulence.Second,we discuss the findings on the accumulation of the swimmers.Last,we review recent progresses concerning the behaviour of gyrotactic swimmers in free-surface turbulence.

Effect of Aspiration and Mean Gain on the Emergence of Cooperation in Unidirectional Pedestrian Flow

When more than one pedestrian want to move to the same site, conflicts appear and thus the involved pedestrians play a motion game. In order to describe the emergence of cooperation during the conflict resolving process, an evolutionary cellular automation model is established considering the effect of aspiration and mean gain. In each game, pedestrian may be gentle cooperator or aggressive defector. We propose a set of win-stay-lose-shrift （WSLS） like rules for updating pedestrian＇s strategy. These rules prescribe that if the mean gain of current strategy between some given steps is larger than aspiration the strategy keeps, otherwise the strategy changes. The simulation results show that a high level aspiration will lead to more cooperation. With the increment of the statistic length, pedestrians will be more rational in decision making. It is also found that when the aspiration level is small enough and the statistic length is large enough ail the pedestrian will turn to defectors. We use the prisoner＇s dilernma rnodel to explain it. At last we discuss the effect of aspiration on fundamental diagram.