去除和添加凋落物对马尾松×红锥混交林土壤呼吸的影响

为探讨凋落物输入量改变对马尾松×红锥混交林碳排放的影响,以马尾松×红锥异龄混交林为研究对象,通过添加和去除凋落物人为地改变碳输入,研究凋落物处理方式对土壤呼吸的影响。结果表明:(1)去除凋落物可降低土壤湿度、提高土壤温度,而添加凋落物则提高土壤湿度、降低土壤温度。去除凋落物使土壤年均呼吸速率显著降低27.88%,而添加凋落物则使土壤年均呼吸速率显著增加34.02%。(2)去除凋落物能降低四季的土壤呼吸累积排放量,而添加凋落物则提高四季的土壤呼吸累积排放量。对照、去除和添加凋落物的土壤呼吸的年累积排放量(以C计)分别为(9.51±0.12) t·hm~(-2)、(6.88±0.21) t·hm~(-2)和(12.70±0.53) t·hm~(-2),可见去除凋落物使土壤呼吸年累积排放量降低27.66%,而添加凋落物使土壤呼吸年累积排放量提高33.54%。(3)不同凋落物处理方式下土壤呼吸速率与土壤温度均呈显著相关,土壤温度解释了土壤呼吸速率变异程度的74.26%～94.28%。去除凋落物增加了土壤呼吸温度敏感性系数Q10值,而添加凋落物则降低Q10值。凋落物处理方式对马尾松×红锥异龄混交林土壤呼吸产生了显著影响,证明凋落物对于改变森林生态系统土壤呼吸和碳循环具有重要作用。     

Spark环境下基于网格索引的轨迹k近邻查询方法

移动对象轨迹的k近邻(k nearest neighbor trajectories,kNNT)查询是一种重要的空间信息服务,主要用于寻找与给定轨迹最近邻的k条轨迹,被广泛地应用于智能交通、信息推荐等领域。随着轨迹数据量的快速增长,由于单机计算资源的限制,传统集中式环境下的kNNT查询效率和可扩展性无法满足实际要求。为了解决这个问题,设计了轨迹数据的分布式网格索引结构,该索引在Spark环境下将轨迹切分并映射到网格中,并引入轨迹还原表以保留查询时候选子轨迹段间的连续性。基于此索引,提出了Spark环境下的轨迹k近邻查询方法kNNT-Grid。实验结果表明,kNNT-Grid方法在分布式环境下实现了良好的查询效率和可扩展性,能够应对海量轨迹数据的k近邻查询需求。     

培养基种类及激素配方对青钱柳悬浮细胞次生代谢物质积累的影响

以青钱柳无菌苗诱导出的愈伤组织为材料进行悬浮培养,通过控制基本培养基的种类和激素配方,初步筛选出适合于青钱柳次生代谢产物生产的植物悬浮细胞培养体系。结果表明:青钱柳悬浮细胞培养的最佳基本培养基为MS培养基,激素配方为1.0 mg/L NAA+0.5 mg/L KT;有利于青钱柳悬浮细胞的干质量增加、次生代谢产物生产的基本培养基为MS培养基;有利于青钱柳悬浮细胞总黄酮积累的激素配方B1为1.0 mg/L NAA+0.5mg/L KT,有利于青钱柳悬浮细胞多糖积累的激素配方B3为1.0 mg/L IBA+0.5 mg/L TDZ,有利于青钱柳悬浮细胞总三萜积累的激素配方B2为0.5 mg/L 2,4-D+0.3 mg/L NAA。     

越南植保机械发展及中越植保机械合作分析

阐述了越南农林生产经济区域、耕作类型和植物保护现状,归纳分析越南植物保护机械的应用及存在问题,并探讨了中越植物保护机械化在植保机械开发、推广和人员培养等方面的合作研究与发展方向。     

上覆强透水层的双层土质边坡降雨入渗特征

为研究浅层强透水的双层土质边坡降雨渗流特征，建立均质粉土与砂土-粉土的土柱、边坡模型，依据基质吸力与含水率的控制方程，分析了土层渗透性、地下水、坡度对饱和区成形影响.结果表明:砂土-粉土柱产生饱和区，既因土层渗透差导致雨水在砂土底层蓄积，又因粉土表面的渗流速度陡降；砂土-粉土边坡饱和区在土层界面首先产生，在纵向上以界面为中心逐渐往各土层内扩展，同时沿土层界面往坡顶上发展，其延伸长度随着地下水位升高而逐渐增大，但地下水位2m与1m时，坡度越大，延伸长度越小；地下水位与坡度均影响土层界面的初始饱和度.     

Modeling and Simulation of P-Aloha,CSMA/CA and MACAW Protocols for Underwater Acoustic Channel

Medium access control( MAC) protocol of underwater acoustic communication network is a key technology for underwater acoustic networks( UANs). Most of the MAC protocols for wireless terrestrial communication networks have been designed with negligible propagation delay. If it is deployed directly in an underwater environment,the UANs will perform inefficiently. In this paper,the characteristics of underwater acoustic channel are modeled and simulated by using the OPNET simulation tool,which are the speed of sound, propagation loss, and four sources for ambient noise: the turbulence,shipping,wind driven waves and thermal noise. The performance of pure Aloha( P-Aloha),carrier sense multiple access with collision avoidance( CSMA / CA) and multiple access collision avoidance for wireless local area network( MACAW) protocols in underwater acoustic channel environment are evaluated. The different performance of protocols in underwater environment is compared in the simulation.     

电化学方法制备聚苯胺膜及其表征

在室温条件下的酸性溶液中,以铜片为电极,采用液体的苯胺单体作为反应剂,通过扫描伏安法制备聚苯胺薄膜.利用循环伏安法(cyclic-voltametry,C-V)、扫描电子显微镜(scanning electron microscope,SEM)、X-射线衍射测试(X-ray diffraction,XRD)等手段对样品进行表征,同时详细考察合成条件对材料性能的影响.结果表明,在苯胺浓度为0.1 mol/L,硫酸浓度为1.0 mol/L,盐酸浓度为0.5 mol/L的混合溶液中,当扫描速度为0.06 V/s时,可获得颗粒尺寸在100 nm以下且均匀度比较高的聚合物.该聚合物具有良好的氧化还原可逆性.     

A rough granular computing in discovery of process models from data and domain knowledge

The rapid expansion of the Internet has resulted not only in the ever growing amount of data therein stored, but also in the burgeoning complexity of the concepts and phenomena pertaining to those data. This issue has been vividly compared by the renowned statistician, prof. Friedman of Stanford University, to the advances in human mobility from the period of walking afoot to the era of jet travel. These essential changes in data have brought new challenges to the development of new data mining methods, especially that the treatment of these data increasingly involves complex processes that elude classic modeling paradigms. “Hot” datasets like biomedical, financial or net user behavior data are just a few examples. Mining such temporal or stream data is on the agenda of many research centers and companies worldwide. In the data mining community, there is a rapidly growing interest in developing methods for process mining, e.g〖DK〗., for discovery of structures of temporal processes from data. Works on process mining have recently been undertaken by many renowned centers worldwide. This research is also related to functional data analysis , cognitive networks , and dynamical system modeling, e.g., in biology. In the lecture, we outline an approach to discovery of processes from data and domain knowledge which is based on the roughgranular computing.     

现代越南语中的汉越词及其变异研究

从社会语言学的"变异"概念出发对汉越词的概念及其变异问题进行讨论。认为"汉越词"指用汉越音来读的汉语词汇,它融入了越南语并成为越语词汇系统中要素之一。汉越读法的形成与越南语历史语音方言有关。无论从理论上还是实践上,并不是所有的汉字(汉语词)一加上汉越语音外壳就能成为汉越词素的,因此还要区分"汉越词"和"汉越读法的汉语词"两个概念。