Spatial-temporal Patterns and Driving Forces of Water Retention Service in China

Overwhelming water-deficiency conditions and an unbalanced water supply and demand have been major concerns of both the Chinese government and the general public during recent decades. Studying the spatial-temporal patterns and impact factors that influence water retention in China is important to enhance the management of water resources in China and other similar countries. We employed a revised Integrated Valuation of Ecosystem Services and Tradeoffs(InVEST) model and regression analyses to investigate the water retention service in China. The results showed that the southeastern China generally performed much better than Northwest China in terms of the spatial distribution of water retention. In general, the efficacy of the water retention service in China increased from 2000 to 2014; although some areas still had a downward trend. Water retention service increased significantly(P < 0.05) in aggregate in the Qinghai-Tibet Plateau, and the Da Hinggan Mountains and Xiao Hinggan Mountains. However, the service in southwestern China showed a decreasing trend(P < 0.05), which would have significant negative impact on the downstream population. This study also showed that in China the changes in water retention service were primarily due to climate change(which could explain 83.49% of the total variance), with anthropogenic impact as a secondary influence(likewise the ecological programs and socioeconomic development could explain 9.47% and 1.06%, respectively). Moreover, the identification of water retention importance indicated that important areas conservation and selection based on downstream beneficiaries is vital for optimization protection of ecosystem services, and has practical significance for natural resources and ecosystem management.

Landscape pattern change and driving force of blowout distribution in the Hulun Buir Sandy Grassland

The land coverage pattern changes for the past 50 years in a typical region of the Hulun Buir Sandy Grassland were interpreted and analyzed based on a series of remote sensing images in 1959, 2002, 2004 and 2009. The temporal and spatial changes of landscape patterns were revealed and the driving forces were analyzed. The results show that all land coverage types had large variable amplitudes. The grassland area decreased, whereas other areas incleased. Owing to implementation of artificial sand fixation from 2004 to 2009, the areas of flowing blowouts and depositional area decreased by 71,369 and 128,835 m2, respectively. The average patch area reduced, but the number of blowouts increased, fractal dimension increased, and blowout structure became complex. The fragmentation index increased, whereas contagion index decreased. Driving force analysis shows that human factors such as overglazing are slightly larger than natural factors of increased temperature and decreased precipitation

Pattern Tree最小简单分解策略

PatternTree(PTQ)是复杂的树状结构,求解PTQ需要在XML文档集合中查找与之匹配的数据。在PTQ中,只有部分节点是需要输出的查询目标节点,其余节点则是中间结果。因此,如何在求解过程中尽量避免中间结果的产生,是XML查询优化面临的一个关键问题。论文提出了一种PTQ分解策略,能够根据不同查询操作的粒度,将PTQ分解为可用一种内部操作实现的最大片断集合。从而有效的限制中间结果的产生,提高查询效率。

基于模式语义的非膨胀性Pattern Tree简化

近年来,XQuery逐渐成为XML查询语言的事实标准。PatternTree被广泛应用于XQuery查询处理。PatternTree用匹配方法处理查询,其本身的大小和复杂程度决定了匹配的效率。该文论述了利用模式语义简化PatternTree的规则。这种方法避免了因插入冗余节点而导致PatternTree的膨胀。三个判断冗余节点的规则不但可以判断叶节点的冗余,而且可以在保留叶节点的情况下,判断非叶节点的冗余。实验证明了方法的可行性和有效性。

First flush of storm runoff pollution from an urban catchment in China

Storm runoff pollution process was investigated in an urban catchment with an area of 1.3 km^2 in Wuhan City of China. The results indicate that the pollutant concentration peaks preceded the flow peaks in all of 8 monitored storm events. The intervals between pollution peak and flow peak were shorter in the rain events with higher intensity in the initial period than those with lower intensity. The fractions of pollution load transported by the first 30% of runoff volume （FF30） were 52.2%-72.1% for total suspended solids （TSS）, 53.0%-65.3% for chemical oxygen demand （COD）, 40.4%-50.6% for total nitrogen （TN）, and 45.8%-63.2% for total phosphorus （TP）, respectively. Runoff pollution was positively related to non-raining days before the rainfall. Intercepting the first 30% of runoff volume can remove 62.4% of TSS load, 59.4% of COD load, 46.8% of TN load, and 54.1% of TP load, respectively, according to all the storm events. It is suggested that controlling the first flush is a critical measure in reduction of urban stormwater pollution.

利用J2EE模式构建教学辅助网站

本文探讨了在使用J2EE技术构建一个基于教师的教学辅助网站系统过程中,一些java pattern(设计模式)的使 用思路,并且给出了简略的功能代码样板。

Effects of grain size on landscape patterns in mineral resource zones:a case study of Wu’an,China

A mineral resource zone,rich in resources and energy,is intensively developed and disturbed by human activities,which causes an obvious change of landscapes.Taking Wu’an of Hebei Province,China,as a case study,this paper extracts landscape information of mineral resource zones through overlapping mineral resources distribution map and landscape pattern map.And then,various landscape indices are selected for analyzing the effects of grain size(30,60,90,120,150,180,210,240,270 and 300 m)on landscape patterns.Due to different kinds of landscape information transmitted by indices,the changing trends vary with the increase of grain sizes.Accordingly the landscape indices are classified into three types of effects:disturbance,continuity and sustainability,and each type of effect has its own optimal range for grain sizes.Then the optimal range of grain size on landscape patterns in mineral resource zones is gained through a comparison of the effects in various grain sizes of landscape indices.The best first domain of scale covers 30-90 m,with a suitable grain size of 30-60 m before intensive mining and a suitable grain size of 60-90 m after intensive mining.Besides,the suitable grain sizes for reflecting disturbance,continuity and sustainability before intensive mining are 30-60,30-60 and 30-90 m,respectively,however,the sizes are changed to 60-90,60-90 and 30-90 m,respectively,after intensive mining.The results are helpful for rational land use and optimal landscape allocation.

THE PATTERN OF FIRE DISTURBANCE IN LIANGSHUI NATURE RESERVE

Fire disturbance pattem of Liangshui Nature Reserve was studied by investigating fire scar tree and analyzing distribution of charcoal particle in soil-layer. The results show that : fire disturbance regular is related with the accumulation and disposition of fuels in space pattern. rye fire protection measures wers put forward for Liangshui Nature Reserve.

Molecular Analysis and Expression Patterns of Four 14-3-3 Genes from Brassica napus L.

In eukaryotes,14-3-3 proteins constitute a family of ubiquitous regulatory molecules.They play very important roles in many cell processes.However,their enconding genes and roles in plants remain to be elucidated.In this paper,four 14-3-3 genes from Brassica napus L.were obtained by randomly sequencing a full-length cDNA library and named as Bn1433-1-4 respectively.The phylogenetic comparison with Arabidopsis 14-3-3 family showed that Bn1433-1 and Bn1433-2 belonged to Episilon group while Bn1433-3 and Bn1433-4 belonged to non-Episilon group.The transcript levels of four Bn1433 genes were analyzed in different organs,various stress conditions and some hormone treatments by real-time PCR.The result showed that all the Bn1433s were expressed constitutively in roots,stems,leaves and immature seeds except that Bn1433-4 exhibited strong expression in immature seeds of 14 and 28 DAF（day after flowering）.By the analysis of real-time PCR,different expression patterns of Bn1433s were studied in various stress conditions and hormone treatments.It was suggested that the functions of Bn1433s are diverse and they are involved in the regulation of various stresses and hormones treatments.

Effects of riparian vegetation patterns on the distribution and potential loss of soil nutrients： a case study of the Wenyu River in Beijing

A riparian ecosystem is an ecological transition zone between a river channel and terrestrial ecosystems. Riparian ecosystems play a vital role in maintaining stream health and bank stabilization. The types of riparian vegetation have changed greatly because of human activities along the Wenyu River. This study examines the impact of riparian vegetation patterns on water pollution due to soil nutrient loss. Four riparian vegetation patterns from the river channel to the upland were chosen as the focus of this study： grassland, cropland, grassland- cropland, and grassland-manrnade lawn. The different distributions of soil nutrients along vegetation patterns and the potential risk of nutrient loss were observed and compared. The results showed that riparian cropland has the lowest value of total nitrogen （TN）, total phosphorus （TP）, available nitrogen （AN）, available phosphorus （AP）, and organic matter （OM）, but it has the highest soil bulk density （BD）. The distributions of soil TN, TP, AN, AP, and OM exhibited a declining trend from the upland toward the river channel for riparian cropland, whereas a different trend was observed for the riparian grassland. The vegetation patterns of grassland-cropland and grassland- manmade lawn show that the grassland in the lower slope has more nutrients and OM but lower soil BD than the cropland or manmade lawn in the upper slope. So, the lower-slope grassland may intercept and infiltrate surface runoff from the upland. The lower-slope grassland has higher levels of soil TN, TP, AN, and AP, and thus it may become a new source of nutrient loss. Our results suggest that the management of the riparian vegetation should be improved, particularly in densely populated areas, to control soil erosion and river pollution.

Research on TemporaI and Spatial Patterns and Dynamic Laws of Soil Water at Eco-tope between Oasis and Desert

Based on long term and stationary research, the temporal and spatial patterns and dynamic laws of soil water content in Minqin desert area were studied. Some results are as follows:(1)The change of soil water content in different years is not obviously in shrub sand dune of Nitraria sibirica and Tamarix ramosissima, but it was great in shifting sand dune, the maximum is 2.538%; (2)The season dynamics can be divided into three stages: accumulating, consuming and stable; (3) The vertical change of soil wa...

Feature Extraction and Identification in Distributed Optical-Fiber Vibration Sensing System for Oil Pipeline Safety Monitoring

High sensitivity of a distributed optical-fiber vibration sensing （DOVS） system based on the phase-sensitivity optical time domain reflectometry （Ф-OTDR） technology also brings in high nuisance alarm rates （NARs） in real applications. In this paper, feature extraction methods of wavelet decomposition （WD） and wavelet packet decomposition （WPD） are comparatively studied for three typical field testing signals, and an artificial neural network （ANN） is built for the event identification. The comparison results prove that the WPD performs a little better than the WD for the DOVS signal analysis and identification in oil pipeline safety monitoring. The identification rate can be improved up to 94.4%, and the nuisance alarm rate can be effectively controlled as low as 5.6% for the identification network with the wavelet packet energy distribution features.

Enhanced performance of InGaN/GaN multiple quantum well solar cells with patterned sapphire substrate

In this paper, the enhanced performance of InGaN/GaN multiple quantum well solar cells grown on patterned sapphire substrates （PSS） was demonstrated. The short-circuit current （Jsc） density of the solar cell grown on PSS showed an improvement of 60%, compared to that of solar cells grown on conventional sapphire substrate. The improved performance is primarily due to the reduction of edge dislocations and the increased light absorption path by the scattering from the textured surface of the PSS. It shows that the patterned sapphire technology can effectively alleviate the problem of high-density dislocations and low Jsc caused by thinner absorption layers of the InGaN based solar cell, and it is promising to improve the efficiency of the solar cell.

Associative categorization of frequent patterns based on the probabilistic graphical model

Discovering the hierarchical structures of differ- ent classes of object behaviors can satisfy the requirements of various degrees of abstraction in association analysis, be- havior modeling, data preprocessing, pattern recognition and decision making, etc. In this paper, we call this process as associative categorization, which is different from classical clustering, associative classification and associative cluster- ing. Focusing on representing the associations of behaviors and the corresponding uncertainties, we propose the method for constructing a Markov network （MN） from the results of frequent pattern mining, called item-associative Markov net- work （IAMN）, where nodes and edges represent the frequent patterns and their associations respectively. We further dis- cuss the properties of a probabilistic graphical model to guar- antee the IAMN＇s correctness theoretically. Then, we adopt the concept of chordal to reflect the closeness of nodes in the IAMN. Adopting the algorithm for constructing join trees from an MN, we give the algorithm for IAMN-based associa- tive categorization by hierarchical bottom-up aggregations of nodes. Experimental results show the effectiveness, efficiency and correctness of our methods.