Management of Mixed Deciduous Forest in Central Cambodia-A Case Study in Sandan District

Cambodia was one of the most heavily forested countries in the world, but a large proportion of forest has been destroyed as a result of wars and political instability over the past 30 years. Forest management in Cambodia has been difficult due to the lack of information on scientific research. It is believed that one of the key points to ensure the sustainable management of the forests is to understand their population dynamics. The aim of this paper is to provide useful information on the population dynamics of Cambodia' s deciduous forest, as a basis for management decision making. Having approximately 50% evergreen tree species, mixed deciduous forest is managed for commercial and non-commercial wood production on a 25-30 years selective felling cycle. Under the national forest inventory project, four clusters were established in Sandan's deciduous forest, containing 36plots or 4.32ha of forest. Statistical analysis showed that the average density was 626 trees/ha, of which dipterocarp, non -dipterocarp and unknown trees were 57 trees, 339 trees and 230trees, respectively. In percentage terms by families, 11% of total trees were from the family Lyrthraceae; followed by 9% the family of Dipterocarpaceae; and 36% of unknown and minor families. The average stand volume per hectare was 178m3, of which approximately 66% were those of trees with diameters greater than 45cm. On a felling cycle of 30years, the mean annual allowable harvest volume theoretically was 35 m3/ha, 8% of which came from dipterocarp trees. Based on forest management experiences in other Southeast Asian countries, 30m3/ha is recommended to extract pending the data on growth rate becomes available. There is a need to firmly protect the forests from repeated encroachments so that the residual stands can naturally regenerate and reach the harvestable size over a period of 30 years. While enrichment planting of commercial species is required, further vegetation research is also needed since the proportion of unknown trees is still high. All these trees will produce additional wood for the present and future needs. In addition, political will and the cooperation of all parties involved are, in priority, required to ensure long -term sustainable management of the forest resources.Article信州大学農学部演習林報告 38: 117-125(2002)departmental bulletin pape

Double differential cross section for light mass fragment production on tens of MeV proton, deuteron, helium and carbon induced reactions

Double differential cross sections (DDXs) of light mass fragment (LMFs - Li,Be,B,C,N and O) productions were measured for tens of MeV proton, deuteron helium and carbon induced reactions on Be, C, Al, Ti and Cu targets. The incident energies for the measurements were chosen to allow us to compare DDXs with same incident energy but different projectiles on various targets. Systematic data were obtained to see the differences between projectile energies, particles, targets and emitted particles. From the comparison, reaction processes of not only evaporation from complete fusion nucleus, but also scattering, pickup, stripping and projectile fragmentation were observed

Research and Design of a Routing Protocol in Large-Scale Wireless Sensor Networks

无线传感器网络，作为全球未来十大技术之一，集成了传感器技术、嵌入式计算技术、分布式信息处理和自组织网技术，可实时感知、采集、处理、传输网络分布区域内的各种信息数据，在军事国防、生物医疗、环境监测、抢险救灾、防恐反恐、危险区域远程控制等领域具有十分广阔的应用前景。 本文研究分析了无线传感器网络的已有路由协议，并针对大规模的无线传感器网络设计了一种树状路由协议，它根据节点地址信息来形成路由，从而简化了复杂繁冗的路由表查找和维护，节省了不必要的开销，提高了路由效率，实现了快速有效的数据传输。 为支持此路由协议本文提出了一种自适应动态地址分配算——ADAR（AdaptiveDynamicAddre...As one of the ten high technologies in the future, wireless sensor network, which is the integration of micro-sensors, embedded computing, modern network and Ad Hoc technologies, can apperceive, collect, process and transmit various information data within the region. It can be used in military defense, biomedical, environmental monitoring, disaster relief, counter-terrorism, remote control of haz...学位：工学硕士院系专业：信息科学与技术学院通信工程系_通信与信息系统学号：2332007115216

Angular distribution of evaporated protons from 50-MeV-range proton-nucleus reactions

The angular distribution of compound reactions at bombarding energies lower than 10 MeV is known to be 90˚ symmetry. At the higher incident energies, 50-MeV range, the quantization axis tilts from the beam axis due to the particle emission in the cascade or the pre-equilibrium process. Therefore, it is necessary to know the tilted quantization axis for the angular distribution calculation of the evaporated protons from (p, p’x) reactions. In the present work, we applied the intranuclear cascade (INC) model to determine the tilted quantization axis by a classical vector analysis. The proton evaporation was calculated by the generalized evaporation model (GEM). By fitting calculations to experimental angular distributions, we deduced the angular momentum transfer from the equilibrium state

Cephalopods eaten by pelagic fishes in the tropical east Pacific, with special reference to the feeding habitat of pelegic fish

Cephalopods removed from stomachs of pelagic fish in tropical East Pacific were examined. From 131 stomachs of 14 pelagic fish species, more than 40 cephalopod species of 20 families were identified. 30% of prey cephalopods were occupied by the onychoteuthids consisting by at least 3 species followed by the Ommastrcphidae (14%), and tho Bolitaenidae (7.0%). Predominant prey species for Xiphias gladius was epipelagic octopus, Tremoctopus violaceus, which shared 17% in number. There were some differences between prey species composition between two species of tunas, Thunnus obesus and T. albacares. T. obesus fed on more deeply distributed. mesopelagic species than T. albacares. A coincidence in time and depth was detected between predatory fish and prey cephalopods. Small onychoteuthid species, Onykia rancureli was most abundant in number among prey cephalopods (21%). 1t shared 29% of prey cephalopods for Thunnus obesus. From frequency of occurrences in fish stomach contents, 0. rancureli seems to live in epipelagic or upper mesopelagic waters, abundant around the bottom of mixing layer, and thus plays an important role among food of T. obesus and T. albacares. From the species composition of eaten cephalopods, the major large pelagic fish discrete feeding depth with minor overlaps, such as, surface layer for bill- and swordfish, around bottom of mixing layer for tunas, and mid water for rnidwater scornbrids. Only Alepisaurus ferox seems to be a vertical wonderer