放花的人

那束大波斯菊悄悄地放在上行站台下方的铁轨边上.可是为什么不放在站台的下方,而是放在铁轨对面一侧,也就是上行线和下行线之间呢?因此, 这束花沐浴着晨光,鲜明地映入站台上所有乘客的眼帘.

A Review of Applied Methods of Using Solar Energy in Iranian Buildings

Solar energy is the radiant light and heat from the Sun that has been harnessed by human since ancient times. Also secondary solar resources such as wind and wave power, hydroelectric power and biomass account for most of the available renewable energy on Earth, which can be used by human. Architects since alacient times have used various methods to hamesse and employ the solar energy for lighting, cooling and heating and etc. Meanwhile, Iran＇s ancient architecture, as an adaptive one, which consists of various climatic reigns, is filled with abounding examples of using sun energy in buildings. But, unfortunately despite these ancient methods, our modern architects mostly tend to provide energy of buildings with fossil fuels. This increases energy costs of the building＇s and also pollutes the environment. In this article it is intended to consider the ancient ways of using solar energy in Iran, and then suggest new methods for applying in modem buildings. The results of consideration show that among Solar technologies, passive and active methods, Iran＇s ancient architects have used passive methods, for example in mass and space, orientation and settlement of building. The idea of passive methods can be used in new shapes in current buildings, for instance by using solar space, central yard and etc. The suggestive method in this paper is combining the passive methods with the active ones.

为什么

如果有一天,妈妈和你行走在大自然之中,看到一条河流,你们沿着河流走上一段,你们会不会因为河流来一段对话?来读读这首小诗——《河流》(谷川俊太朗)妈妈河流为什么笑因为太阳在逗它呀妈妈河流为什么在歌唱因为云雀夸赞着它的浪声妈妈河流为什么冰凉因为想起了曾被雪爱恋的日子妈妈河流多少岁了总是和年轻的春天同岁.

Particle Paths of Lagrangian Velocity Distribution Simulating Yin-Yang Balance in Ancient Tai-Chi Diagram

The particle paths of the Lagrangian flow field simulate very well the interface curve of the Yin-Yang balance in the ancient Tal-Chi diagram. There are four forms called the ＂four states＂ in the Tai-Chi diagram. Of the four states, under Yang are the Major Yang and the Minor Yin, and under Yin are the Major Yin and the Minor Yang. The present study provides the proper positions of the four states in the ancient Tal-Chi diagram. The Fu Xi＇s Eight Trigrams Chart located along the ancient Tai-Chi diagram is also developed in the present study. The interface curve of Yin-Yang in the ancient Tai-Chi diagram has never been described mathematically. It can now be formulated by the equations describing the particle paths in the Lagrangian flow field.

Satellite-based Estimates of Canopy Photosynthetic Parameters for an Alpine Meadow in Northern Tibet

Plant photosynthesis is the fundamental driver of all the biospheric functions. Alpine meadow on the Tibetan Plateau is sensitive to rapid climate change, and thus can be considered an indicator for the response of terrestrial ecosystems to climate change. However, seasonal variations in photosynthetic parameters, including the fraction of photosynthetically active radiation by canopy(FPAR), the light extinction coefficient(k) through canopy, and the leaf area index(LAI) of plant communities, are not known for alpine meadows on the Tibetan Plateau. In this study, we used field measurements of radiation components and canopy structure from 2009 to 2011 at a typical alpine meadow on the northern Tibetan Plateau to calculate these three photosynthetic parameters. We developed a satellite-based(NDVI and EVI) method derived from the Beer-Lambert law to estimate the seasonal dynamics of FPAR, k,and LAI, and we compared these estimates with the Moderate Resolution Imaging Spectroradiometer(MODIS) FPAR(FPAR_MOD) and LAI product(LAI_MOD). The results showed that the average daily FPAR was 0.33, 0.37 and 0.35, respectively, from 2009 to 2011, and that the temporal variations could be explained by all four satellite-based FPAR estimations, including FPAR_MOD, an FPAR estimation derived from the Beer-Lambert law with a constant k(FPAR_LAI), and two FPAR estimations from the nonlinear functions between the ground measurements of FPAR(FAPRg) and NDVI/EVI(FPAR_NDVI and FPAR_EVI). We found that FPAR_MOD seriously undervalued FPARg by over 40%. Tower-based FPAR_LAI also significantly underestimated FPARg by approximately 20% due to the constant k(0.5) throughout the whole growing seasons. This indicated that using FPAR_LAI to validate the FPAR_MOD was not an appropriate method in this alpine meadow because the seasonal variation of k ranged from 0.19 to 2.95 in this alpine meadow. Thus, if the seasonal variation of k was taken into consideration, both FPAR_NDVI and FPAR_EVI provided better descriptions, with negligible overestimates of less than 5% of FAPRg(RMSE=0.05), in FPARg estimations than FPAR_MOD and FPAR_LAI. Combining the satellite-based(NDVI and EVI) estimations of seasonal FPAR and k, LAI_NDVI and LAI_EVI derived from the Beer-Lambert law also provided better LAIg estimations than LAI_MOD(less than 30% of LAIg). Therefore, this study concluded that satellite-based models derived from the Beer-Lambert law were a simple and efficient method for estimating the seasonal dynamics of FPAR, k and LAI in this alpine meadow.