Improving Indigenous Technologies for Sustainable Land Use in Northern Mountainous Areas of Vietnam

More than 30 ethnic groups are now living in northern mountainous regions, Vietnam, mainly relying on shifting cultivation with the fallow period being shortened from time to time. Naturally, soil fertility reduces from cycle to cycle, entailing the reduction of productivity. Large areas of moderately sloping lands suitable for upland agriculture have become bare after many cultivation-fallow cycles. The soils there have been severely degraded with more toxicity, low porosity, low water retention capacity and poor floral diversity. Normally, these lands cannot be used for food crop cultivation. So farmers in uplands have to rely on slash-and-burn practices for their livelihood. As there is no more forest with good soil in medium slopes, farmers go to cut forests in watershed, high slope lands and old forests up to the mountains‘ top. There are ecologically and environmentally very sensitive areas, so their destruction will inevitably cause hazardous consequences in the whole basin. Meanwhile,cultivation in these areas has low economic efficiency and sustainability because the crop yield may decrease very fast due to severe erosion as the higher the slope, the more serious erosion. Consequently living standards of highland farmers remain low and unstable. Sustainable farming on these lands in the perspective of a seriously deteriorated ecology and environmental is not an easy task. There have been many projects trying to help mountainous farmers get out of their vicious circle. However, due to different reasons, the results gained are low, and in some cases,things ceased to move after the projects phased out. During past few years, based on the farmer experiences, the Vietnam Agricultural Science Institute has cooperated with local and international partners to implement different projects in order to solve the problems by developing simple, easy and cheap cultivation technologies, which can be accepted and applied by local poor farmers for sustainable agricultural production. The first results of our activities offered good opportunities for sustain food production, improve soil health, recharge of aquifers,and enhanced household income for better rural lively hoods in the upland eco-regions of northern Vietnam.     

二层交换机转发帧的原理与实现

介绍了二层交换机转发帧的原理及其具体的硬件和软件实现.着重讲解了其软件实现的过程中,在各种端口上设置MAC地址的处理方法.     

基于模糊Hopfield神经网络的大气降水粒子分类

提出基于模糊Hopfield神经网络的大气降水粒子分类,它是通过计算样本间的模糊关系的相似程度,再加上Hopfield网络所特有的高稳定性,对大气降水粒子进行分类.通过对各降水粒子所对应雷达回波数据的分析,验证了方法的可行性.     

用孕镶金刚石钻头处理金刚石钻进孔内事故的体会

金刚石钻进工艺已被广泛应用，与合金、钢粒等钻进方法比有其自身独特的优势，特别对于可钻性等级高、研磨性高的岩层，更显金刚石钻进优势。但在小口径金刚石钻进中，孔内烧钻事故的处理一直是一个比较复杂的难题，一旦处理不当，不但影响生产进度，还会造成较大的经济损失。在我队小口径金刚石钻进的进程中，     

惠民县为46家砖瓦窑厂进行“健康”查体

为切实做好全县非煤矿山企业的安全生产工作，杜绝矿山企业“带病”开采，防患于未然，8月26日开始，惠民县国土局利用为期3个月的时间，组织人员对全县46家砖瓦窑厂的安全生产工作进行集中检查。此次安全生产检查主要是查看砖瓦窑厂生产是否符合技术规程要求，开采方法是否规范合法，应急处置措施是否落实到位，安全生产规章制度是否健全。[第一段]     

山西省沁水县征地统一年产值标准测算方法

通过对山西沁水县征地统一年产值标准的测算方法进行详细分析,制定出了沁水县征地统一年产值科学合理的标准,对山西其他县市制订征地统一年产值标准提供了可借鉴的模式.     

数字填图技术在区域地质调查中的应用

以1∶25万西宁市、门源县幅区域地质调查实施过程中采用数字填图技术方法为例,探讨了数字填图技术在区域地质调查工作中的应用,总结了一些实践经验,对存在问题及其解决方法提出了一些建议。     

基于UC/OS-Ⅱ的UCGUI和LWIP资源整合的研究

介绍了针对实时内核UC/OS-Ⅱ的资源扩展,主要是UCGUI和LWIP的资源整合,探讨了两者在UC/OS-Ⅱ中的移植方法,丰富了UC/OS-Ⅱ的功能.     

書報介紹

I.動力氣象之問題舆方法(Methoden und Problems der Dynami-sche Meteorologic)Ergebnisse der Mathematik und ihrer Grenzgebiete,Vol.V,No.3,122pp.14 figs.,J.Springer,Berlin 1938.H.Ertel 著斯書都分3章24節,第一章敍述大氣熱力學及流體力學之精羲,其中對於大氣之組成,氣體状態方程式,熱力學二大定律,熱力平衡條件,熱力勢,特殊勢力状態變化,循環步驟,乾濕空氣之熱力學,輻射理論,流體力學中之奥氏及拉氏方程式,均有扼要之論述。第二章為大氣之普通動力學,諸凡自轉地球上之流體運動方程式,調和運動之方程式,涡動舆摩擦,重力勢,壓力場舆質量場,挪威貝鏗銀氏