河南省土地利用变化特征及其空间格局

[目的]通过分析河南省2011~2016年土地利用变化特征和空间格局状况,以期为日后河南省合理开发、利用土地资源提供一定的理论指导。[方法]基于河南省土地变化特征,通过马尔科夫模型对河南省2011~2016年土地变化特征进行分析,从多个角度揭示该地区土地利用结构变化情况,并对河南省土地空间利用变化进行评价。[结果]河南省建设用地增加幅度最大,耕地、水域用地有不同程度的减少。土地空间变换主要表现为耕地和林地、水域用地、建设用地等土地类型之间的变换。由土地利用综合区可知,不同土地类型转换过程中,草地是转换比率最小的类型。[结论]河南省的各类土地利用之间的矛盾日益激烈,直接或间接地影响社会经济制度、土地政策和土地管理,因此,有必要加强开展土地资源管理和规划、保护生态环境等方面的工作。     

Fractal structures and naive trading systems: Evidence from the spot US dollar/Japanese yen

This study investigates whether daily logarithmic returns on the spot US dollar/Japanese yen (USD/Yen) for the period 3 March 1987 to 8 September 1993 displayed an underlying fractal structure. The analysis employed a rescaled range (R/S) technique, and revealed USD/Yen persistence which favoured continued depreciation of the USD. The results suggest the presence of time or memory effects in the currency. These effects were arbitrageable by speculators who by holding long Yen positions were able to earn positive returns.     

试析P2P小额信贷行业立法的调整范围

自银监会《关于人人贷有关风险提示的通知》指出人人贷信贷服务中介公司具有潜在风险,要求银监局采取措施,做好风险预警监测与防范工作。P2P小额信贷行业立法逐渐提上业界和学界议程。对于P2P小额信贷行业立法而言,立法的调整范围直接关系到法的整体架构、宏观方略、微观策略和精神品格,不仅是整个立法工作的起点,也是重点兼难点,值得学界和立法者予以关注并展开广泛讨论。     

Effect of land-use change on soil fertility characteristics within water-stable aggregates of two cultivated soils in northern Iran

Forest and pastureland soils in highland of northern Iran are being seriously degraded and destructed due to extensive agricultural activities. These land use changes are usually accompanied by decreasing in concentrations of soil organic carbon and nutrients and also deterioration of soil structure in these regions. However, studies on concentration of nutrients and carbohydrates in soils suggest that the location of nutrients within aggregates of each size should be determined. This study was to evaluate the nutrient elements and carbohydrate distributions within water-stable aggregates (WSA) of virgin forest and pasture lands under different land uses in Alborz maintain range, northern Iran. In September 2006, soil samples were collected from depths of 0–20 cm in Typic Haploxerolls soils. The overall pattern indicated that the mean weight diameter (MWD) and WSA were greater in the virgin pasture and forest soils compared with the adjacent cultivated (ex-forest and ex-pasture) soils and aggregates of >1.0 mm size were dominant in the virgin soils, whereas the cultivated soils comprised aggregates of the size ≤0.5 mm. Distribution of organic carbon, nitrogen, phosphorus and carbohydrates within the WSA showed preferential enrichment of these parameters in the macroaggregate fraction (4.75–1.0 mm) for the virgin soils and microaggregate fraction (>0.25 mm) for the exposed soils. Cultivation decreased the concentration of carbohydrates by 23.6% and 20.6% in ex-forest and ex-pasture lands, respectively. Average distribution of total exchangeable bases within WSA showed that the cultivation of forest and pasture soils significantly led to reduce in these nutrient in the 4.75–2.0 mm fraction and increase in concentration of these exchangeable cations in <0.25 mm fractions. In general, results indicated that cultivation significantly led to 71% and 6% reductions in total exchangeable bases within the 4.75–2.0 and <0.25 mm aggregate fraction, respectively, for virgin soil. Since smaller aggregates are preferentially removed by erosion, this study emphasizes the need for sustainable soil management practices that they will minimize nutrient loss when forest or pastures lands are converted to croplands.     

The information content of stock splits

This study examines whether stock splits contain information content about future operating performance or whether splits are undertaken by firms to realign their share prices and to improve trading liquidity. In the four years following split announcements, splitting firms do not experience improved operating performance relative to non-splitting firms. Furthermore, stock split signals are not related to future profitability. The positive announcement effect can be explained by lower share prices and improved market liquidity following stock splits but not by split signals and post-split operating performance. Our results show very little evidence that stock splits signal improvement in long-run operating performance and are more consistent with the trading range/liquidity hypothesis.     

用于建筑结构振动测量传感器参数的选择

在建筑结构振动测量中,经常需要用到传感器来测量其性能指标和其他重要参数。当我们按照仪器使用环境确定所需的传感器类型后,如何根据不同情况选取具体参数的产品显得尤为重要。文章介绍了各种类型建筑结构的基本参数,以合理地选择传感器的通频带、量程及运动参数等。     

车排子处理项目监督工作浅谈

车排子连片三维叠前时间偏移处理项目，是中油监理公司承接新疆油田的第一块连片处理监督项目。通过车排子项目的处理过程监控事例，阐述了处理过程中监督介入的重要性，并为如何做好地震资料处理监督工作提供借鉴。     

关于强夯法地基处理技术若干问题的探讨

本文结合笔者多年工作的实践经验,以强夯法地基处理技术为研究对象,就其加固机理、适用范围、优点和局限性进行了分析研究,谨供大家作参考之用。     

靶场毫米波信号高灵敏度接收与测试新方法

基于靶场毫米波测试中微弱信号（低至-128 dBm）检测的实际需求,通过信噪比分析 ,采用外差式宽带多通道快速扫频复合信道化技术,在W频段实现了-128 dBm接收灵敏 度的测 试系统。同时,设计了毫米波信标源并利用空间衰减理论,提出了一种W频段高灵敏度（- 128 dBm）测试的新方法。理论分析表明,测试距离为290 m、相应的衰减值约为-1 21.5 dB时,可提供一个功率最小达到-128 dBm的W频段毫米波信号源。利用标定后的 毫米波信号源进行外场实际测量,证明了该测试方法的可行性。     

Asymptotic analysis of the ruin with stationary stable steps generated by dissipative flows

We study the exceedance probability of a high threshold (ruin probability) for a random walk with a negative linear drift, where the steps of the walk (claim sizes) constitute a stationary ergodic symmetric α-stable process. We casually use the language of insurance, although this is a popular problem in many other fields of applied probability as well. We refer to ergodic theory to split the step process into two independent processes. We focus on the processes generated by dissipative flows, which are known to have a mixed moving average representation, and we restrict our attention to regular moving averages with non-negative kernels. We give results for the order of magnitude of the exceedance probability as the threshold goes to infinity in the cases of discrete-time and continuous-time claim processes.