主动脉B型夹层覆膜支架植入术后主动脉—支气管瘘1例报告

主动脉腔内修复术(thoracic endovascular aortic repair,TEVAR)是治疗主动脉疾病的重要手段,是一种通过在主动脉腔内植入覆膜支架达到封堵夹层原发破口和出口、恢复主动脉真腔血流、促进夹层假腔血栓形成,加快主动脉重塑的微创手术方式[1]。该手术方法具有创伤小、效果明确、手术风险低的优势,因而在临床应用十分广泛。然而,植入后支架感染是TEVAR术最具威胁的并发症之一,术后30 d死亡率达17%[2],而主动脉—支气管瘘(aorticbronchial fistulas,ABF)是指胸主动脉与邻近气管支气管系统之间的异常交通,罕见但常常危及生命[3]。植入支架感染常并发ABF,往往使病情变得更复杂,需要采取更为积极有效的治疗措施。

Simulation on the dynamics of forest area changes in Northeast China

There is plenty of forests in Northeast China which contributes a lot to the conservation of water and land resources, produces timber products, and provides habitats for a huge number of wild animals and plants. With changes of socio-economic factors as well as the geophysical conditions, there are dramatic changes on the spatial patterns of forest area. In this sense, it is of great significance to shed light on the dynamics of forest area changes to find the underlining reasons for shaping the changing patterns of forest area in Northeast China. To explore the dynamics of forest area change in Northeast China, an econometric model is developed which is composed of three equations identifying forestry production, conversion from open forest to closed forest and conversion from other land uses to closed forest so as to explore the impacts on the forest area changes from demographic, social, economic, location and geophysical factors. On this basis, we employ the Dynamics of Land System （DLS） model to simulate land-use conversions between forest area and non-forest cover and the land-use conversions within the sub-classes of forest area for the period 2000-2020 under business as usual scenario, environmental protection scenario and economic growth scenario. The simulation results show that forest area will expand continuously and there exist various kinds of changing patterns for the sub-classes of forest area, for example, closed forest will expand continuously and open forest and shrub will decrease a little bit, while area of other forest will keep intact. The research results provide meaningful decision-making information for conserving and exploiting the forest resources and makJng out the planning for forestry production Jn the Northeast China region.

Factors and mechanism driving the land-use conversion in Jiangxi Province

This article explores the factors and mechanism driving the land-use conversion at regional level by developing and using an econometric approach which is called the simultaneous equations model （SEM）. A case study in Jiangxi Province of China is conducted by establishing the SEM, which consists of three equations including agricultural production, land conversion of cultivated land to built-up area and land conversion of cultivated land to forest cover/grassland from 1988 to 2005. And then this paper employs the method of piecewise estimation to represent the influences of the factors such as population, society, economy, location and geophysical conditions on the process of land-use conversion in Jiangxi Province. Estimation results show that population is a predominant factor driving the land-use conversion at counties, while social and economic factors are determinant factors in the short term for the entire Jiangxi Province. Specifically, the size of agricultural population and the magnitude of agricultural input determine the agricultural production to a large extent; population size, plain area proportion at counties and land management policies together affect the direction and magnitude of conversion between cultivated land and built-up area; agricultural population proportion, terrain slope, grain production and non-agricultural industry promote the conversion of cultivated land to forest cover/grassland. Furthermore, the explored mechanism also reveals the underlying causes of the land use changes driven by a series of factors in Jiangxi Province. Finally, this paper concludes that factors proven to play an important role in driving the land-use conversion need to be considered when the land management agencies make out the land use planning to optimize the land use, expand the agricultural production, and conserve the cultivated land.

深层砂岩裂缝性气藏缝网压裂裂缝导流能力分析

针对深层、超深层气藏缝网压裂及其裂缝特征,采用高强度支撑剂对支撑裂缝导流能力进行评价,结合岩心裂缝流动实验,对支撑剂不同铺置浓度的支撑裂缝导流能力,岩心单裂缝、多裂缝交错缝的连通与导流能力等进行模拟实验,分析了裂缝连通与支撑对裂缝及裂缝网络渗流性的影响。研究结果表明,裂缝支撑主要有支撑剂铺置支撑、错位缝自支撑和岩石碎块支撑。其中多层铺置和局部单层铺置支撑裂缝具有高导流能力,是缝网裂缝重要的渗流特性。采用变粒径、变黏度、变排量和阶梯连续加砂等技术措施,有利强化复杂裂缝的支撑和提高缝网裂缝的连通性和导流能力。该分析方法对深层、超深层缝网压裂工艺技术的改进具有重要指导性,对页岩等非常规气藏的体积压裂也具有借鉴作用。

Structural Progressive Mode of Urban Renewal and Public Participation in Shenzhen International Low Carbon City

By means of a structural progressive mode of urban renewal, which operates through small and medium-scale projects on the basis of public participation, the Shenzhen International Low Carbon City has provided propagable and replicable experience for urban planning and construction in urban marginal areas. This article fi rstly introduces the improvement measures for willingness and capabilities of public participation in the process of structural progressive renewal in the Shenzhen International Low Carbon City, and expounds the construction methods of participation approach, feedback mechanism, and interest balance, followed by an introduction of the rolling development strategy, micro municipal construction strategy and spatial-industrial-ecological integrated development strategy and practice experience, hoping to serve as a reference for the planning and construction of other cities in China.