Study on the Construction of "Near Nature" Waterfront Greening Landscape

The construction of 'Near Nature' waterfront greening landscape is a kind of waterfront construction model that complies with the nature and balances ecological landscape and regional development, which is of great significance to restore the healthy waterfront ecosystem and sustainable development. Starting from the conception and characteristics of 'Near Nature' waterfront greening areas, the design principles and construction schemes of waterfront greening landscape such as river, lake, canal and wetland were studied.

SCHEMES OF GAS PRODUCTION FROM NATURAL GAS HYDRATES

Natural gas hydrates are a kind of nonpolluting and high quality energy resources for future, the reserves of which are about twice of the carbon of the current fossil energy (petroleum, natural gas and coal) on the earth. And it will be the most important energy for the 21st century. The energy balance and numerical simulation are applied to study the schemes of the natural gas hydrates production in this paper,and it is considered that both depressurization and thermal stimulation are effective methods for exploiting natural gas hydrates, and that the gas production of the thermal stimulation is higher than that of the depressurization. But thermal stimulation is non-economic because it requires large amounts of energy.Therefore the combination of the two methods is a preferable method for the current development of the natural gas hydrates. The main factors which influence the production of natural gas hydrates are: the temperature of injected water, the injection rate, the initial saturation of the hydrates and the initial temperature of the reservoir which is the most important factor.

Patterns of human-wildlife conflict and compensation practices around Daxueshan Nature Reserve, China

Understanding the spatial patterns of human-wildlife conflict is essential to inform management decisions to encourage coexistence, but it is constrained by the lack of spatially-explicit data. We collected spatially-implicit data of human-wildlife conflicts from 2009-2015 around Daxueshan Nature Reserve, Yunnan, China, and investigated the patterns and drivers of these conflicts. A questionnaire was also designed to capture local resident attitudes toward insurance-based compensation for the losses caused by targeted wildlife. We found that the Asiatic black bear （Ursus thibetanus） was the most conflict-prone animal around the reserve, followed by the rhesus macaque （Macaca mulatta） and Southeast Asian sambar （Cervus equinus）. Conflicts were unevenly distributed among seasons, villages, and communities, with several grids identified as conflict hotspots. Poisson models revealed that human-bear conflicts were negatively related to distance to the reserve and proportion of forest, but positively correlated to the proportion of cropland. Binomial models showed that communities affected by crop depredation were positively correlated with the proportion of cropland and negatively correlated with distance to the reserve, whereas communities affected by livestock depredation were negatively correlated with the proportion of cropland. The insurance-based scheme has compensated over 90% of losses, to the satisfaction of 90.6% of respondents. Our results suggest that human-bear conflict could be potentially reduced by eliminating food crops near the reserve boundary and livestock grazing at conflict hotspots.In addition, the insurance-based scheme could be replicated at a broader scale with improvement in loss assessment.

Startup scheme optimization and flow instability of natural circulation lead-cooled fast reactor SNCLFR-100

Owing to the inherent instability of the natural circulation system,flow instability can easily occur during the operation of a natural circulation lead-cooled fast reactor,especially during the startup phase.A comprehensive startup scheme for SNCLFR-100,including primary and secondary circuits,is proposed in this paper.It references existing more mature startup schemes in various reactor types.It additionally considers the restriction conditions on the power increase in other schemes and the characteristics of lead-based coolant.On this basis,the multi-scale coupling code ATHLET-OpenFOAM was used to study the flow instability in the startup phase under different power-step amplitudes and power duration times.The results showed that obvious flow instability phenomena were found in the different startup schemes,such as the short-term backflow phenomenon of the core at the initial time of the startup.Moreover,an obvious increase in the flow rate and temperature to the peak value at the later stage of a continuous power rise was observed,as well as continuous oscillations before reaching a steady state.It was determined that the scheme with smaller power-step amplitude and a longer power duration time requires more time to start the reactor.Nevertheless,it will be more conducive to the safe and stable startup of the reactor.

北京市自然保护地整合优化的思路、成效及反思

2020年,全国开始自然保护地整合优化工作。通过结合《北京市自然保护地整合优化方案》成果及其编制过程,梳理了北京市自然保护地整合优化的思路及其取得的成效,在总结经验、反思问题的基础上,对如何推进整合优化下一步工作提出了建议。

基于自组织特征映射模型(SOFM)网络的中国自然资源生态安全区划

自然资源生态安全是国家安全的重要组成部分,自然资源生态安全区划对保障区域可持续发展提供了重要途径。基于自然资源数据、生态环境数据和相关区划资料,从生态敏感性与生态服务重要性角度构建了自然资源生态安全评价指标体系,进而揭示了中国自然资源生态安全的空间格局;通过建立区划的原则和指标,按照一级区主要反映自然资源空间分布格局,二级区主要揭示自然资源生态安全水平的差异,采用SOFM网络制订了中国自然资源生态安全区划方案。结果显示:(1)中国自然资源生态安全水平整体偏低,以中警与重警状态区域为主,安全和较安全状态的区域仅占24.22%,其中低安全等级区多分布于400mm等降水量线以西的干旱、半干旱区,高安全等级区则集中分布于水热资源与生物资源较为丰富的东南部地区;(2)中国自然资源生态安全区划方案包括8个一级区与27个二级区,总结归纳各大区自然资源的特征和威胁生态安全的问题,并针对二级区自然资源生态安全状况提出了对策建议。研究结果可为分区、分类推进全国自然资源可持续利用和国土空间优化提供理论支持与决策依据。

提高工业厂房自然通风效率的有效方法研究

本文探讨了工业厂房自然通风效率提高的重要性,围绕工业厂房的生产需求,提出了提高工业厂房自然通风效率的整合方案,并且通过工业厂房自然通风效率整合方案在经济效益、通风效率以及能源消耗率等方面的比较,构建了提高工业厂房自然通风效率的有效策略,旨在为满足可持续发展的需求和工业生产的实际需求提供参考性意见。

面向自然语言处理的现代缅文分词规范研制与应用

缅文分词是缅甸语自然语言处理中不可缺少的基础性工作之一,而分词规范则是进行自动分词技术研究的关键问题。该文参考了中文、藏文等文种的分词经验,结合缅文自身特点、缅文在计算机中的编码特点和缅甸语语法,研制了一套较系统的、适用于现代缅文的分词规范;并基于该规范对缅文开源人工标注分词语料库myPOS 0.9进行人工重新标注,实验结果证明在6种常见分词算法条件下该分词规范性能更优。

海洋移动式自安装平台井口支撑方案对比

针对海洋移动式自安装平台,提出了隔水管外置框架支撑、内置框架支撑和张紧式支撑3种方案。采用有限元分析软件ANSYS,建立了对应的平台整体耦合分析模型,开展了平台结构模态和静力分析,进而对3种支撑方案下平台的整体性能进行了对比研究。结果表明:隔水管外置与内置两种框架支撑方案下平台的自振周期差异微乎其微,张紧式支撑会导致隔水管发生低阶振动;隔水管外置框架支撑方案在三者中综合性能表现最优,可作为海洋移动式自安装平台井口区的设计方案。

煤制天然气甲烷合成装置降温技术方案的优化

伊犁新天煤化工煤制天然气甲烷合成装置因工艺停车降温速率慢,导致装置检修进度缓慢,降低了设备可靠性,缩短了催化剂寿命,增加了装置能耗。通过系统梳理甲烷合成装置停车降温技术方案,分析其存在的缺陷,研究提出改变降温换热介质种类和走向等措施优化降温技术方案。结果表明,优化后的甲烷合成装置工艺停车技术方案更为安全、高效。

利用围护结构自然接地的地铁接地方案研究及应用

实际地铁车站工程项目中接地装置四周往往存在土壤电阻率过高、岩石多、施工难度大等问题,常规的接地方案具有一定的局限性;提出利用车站围护结构作为自然接地体的地铁接地方案,分析不同车站形式下的具体方案做法,并将其应用到郑州轨道交通12号线等工程项目中且取得了良好的接地效果;验证了该接地方案相较于常规地铁接地方案具有适应性更强、工序简单、降低施工难度、效果更优等特点,并且可降低建设成本、缩短施工工期。

LNG接收站增设天然气门站功能的建站方案

基于LNG接收站和天然气门站各自的供气特点,以城市土地集约化管理、提高资源利用率为目的,结合项目实际情况,提出了3种LNG接收站增设天然气门站功能的建站方案。从场地规划、技术经济、后期运维等方面进行综合比选,分析各方案的优缺点,推荐更合适的建站方案。这可为同类建设项目提供参考。

Renaturalizing Floodplains

This manuscript analyzes and discusses viewpoints concerning the renaturalization of floodplains as an instrument of management in large catchments, using natural flood defense schemes. Schemes consider the differentiated supply of ecosystemic services based on river channel/floodplain interactions. Conventional structural methods used to prevent flooding (e.g., longitudinal dikes) are increasingly showing themselves to be less efficient with regard to advances in the problems of environmental management of the territory, especially when combined with extreme events, where the importance of perfecting strategies for harmonizing duly controlled floodable areas and water retention can be seen. Natural flood risk reduction measures are part of a holistic solution for sustainable management of flood risk, conservation of nature, water quality and green economy. They rely upon the inherent ability of floodplains to retain water in the basin, and this can delay and reduce peak flows.

The Best Natural Boundary:a New Concept Developed by Combining the Sequence Boundary with the GSSP

Through a detailed study of sequence boundaries, it is concluded that sequence stratigraphy is an independent regional and transitional stratigraphic system between local lithostratigraphy and global chronostratigraphy. Therefore, a new tripartite stratigraphic classification scheme has been proposed. By combining organically the concept of sequence boundaries with the GSSP, it is suggested that the GSSP should be chosen in a conformale portion of a related sequence boundary, and the boundary established in light of this concept is defined as the Best Natural Boundary (BNB). The definition of the BNB points out the working area and stratigraphic level for the GSSP. By referring to a case study of the Permian Guadalupian/Lopingian boundary, the concept of the BNB has been elaborated in detail, and it is proposed that the BNB of the Guadalupian and the Lopingian lies between the Mesogondolella granti Zone and the Ctarkina postbitteri Zone, which is also the sequence chronostratigraphic boundary between the Transpecos composite sequence (chronozone)and the UAA- 1 composite sequence (chronozone).

The Insurance Market of Natural Hazards for Residential Properties in Italy

Insurance is an effective complementary countermeasure for unexpected losses brought about by natural hazards. Coverage can be a useful tool considering in particular that public funds available to compensate for damages are limited and the consequences of catastrophes are becoming more severe over the time. Bearing this in mind, the authors performed a study aiming to clear up the main aspects and limits of the insurance market of natural hazards for residential properties in Italy. The opening sections of the paper give an overview of both the historical extreme events in Europe and Italy, and the reasons for the low insurance penetration rate in Italy. After that, the paper goes to the core of the research casting light upon the insurance market in Italy and examining the features and possible drawbacks of the available insurance covers. In this paper, the geophysical (seismic and volcanic) and hydrological (landslide and flood) hazards are analysed, and the residential stock is taken as a reference. After deepening in the local insurance market, the research focuses on the possible suggestions to stakeholders of how to increase the insurance penetration rate by taking advantage of the international experiences.

中国自然区划研究进展与展望

区划通过构建科学的指标体系,应用先进的技术方法研究区域单元的分异组合和划分合并,以得到地表现象的同质性空间单元,揭示现象或要素在区域内的相似性与区域间的差异性,可为国土规划、资源开发、产业布局、生态文明建设和可持续发展等领域提供参考。该文梳理了国内外自然区划研究进展和各时期特点,根据中国自然区划的理论方法和相关研究成果,总结区划的目标、类别、基本原则、整体思路等内容,并归纳近年来我国综合区划、部门区划的方法体系,以及综合区划、生态区划、气候区划、水文区划、灾害区划等具有代表性的中国自然区划方案。最后,总结了我国现有自然区划研究的特征,并结合当前国家需求分析了区划研究潜在的发展趋势。

“华龙一号”非能动安全壳热量导出系统研究

为了避免类似福岛核泄漏事故的再次发生,各国在第三代核电机组的设计中,考虑采用非能动安全技术。非能动安全壳热量导出系统是我国“华龙一号”最重要的非能动安全系统之一,是实现最高核电建设标准的重要保障。本文主要从系统方案设计、内部换热器热工水力特性分析、系统综合性能实验和安全壳热工水力耦合特性实验等方面对非能动安全壳热量导出系统研究工作进行了总结,介绍了所开展研究的主要内容、所建实验装置的概况和得出的主要结论。上述理论分析和实验验证表明:所开发的非能动安全壳热量导出系统的排热能力远大于设计要求。

海域可燃冰开采集输工艺探讨

可燃冰是世界公认的清洁高效能源之一。中国南海神狐海域2次可燃冰试采显示,该海域可燃冰矿藏呈现游离气和水合物共存的特征,且多分布在泥质粉砂黏土中;采出流体特性具有CH4含量高、产砂及出水量大的特点。针对南海神狐海域可燃冰特点,提出了水下气液分离的预处理方案,对比分析了水下气液分离+砂液回注、气液分输+平台砂液处理、气液混输+平台砂液处理3种集输方案的优缺点。针对水下气液分离+砂液回注方案,探讨了总工艺流程、水下分离工艺和平台工艺流程,论述了方案的可行性。进一步考虑了工艺流程中存在的出砂、水合物二次生成问题,为可燃冰输送过程安全高效运行提供支撑。研究思路和方案设计对中国南海可燃冰矿藏的开发具有一定的参考意义。

海域天然气水合物开采方案设计及气液分离特性分析

为了解决海域天然气水合物开采效率低、水合物大面积分解和二次生成等问题,以我国南海海域某天然气水合物开采井为例,结合降压法和热激法设计一种海域天然气水合物整体开采方案,运用数值模拟方法研究螺旋式、轴流导叶式、管柱式分离装置在不同气液比下分离效率及分离特性,同时开展气液分离实验验证结果准确性。结果表明:海域天然气水合物开采采用双管柱结构方案,生产井采用泄流面积更大的水平井方案。螺旋式分离装置适用于10%的液相含量(体积分数),优选螺旋分离装置进行海域天然气水合物气液分离,螺旋式分离装置前两圈螺旋处压降较大,压降达到325 Pa。液滴直径25~100μm时分离效率均达到了100%,分离效率随圈数的增多而增大,变化范围为79.2%~91.8%。分离效率实验与数值分析结果误差为5%,验证了气液分离数值模拟分析结果的准确性。本研究可为高效安全开发海域天然气水合物提供重要技术支持。

天然气能量计量总体实施方案探索与规划

天然气能量计量是最科学的燃气计量方式,因此全面实施能量计量迫在眉睫。虽然我国实施能量计量的硬件设备已基本成熟,但目前还未能得到广泛普及,原因主要是对能量计量的具体实施方案鲜有研究。以广东省内某长输管道中的A分输站为例,分别从计量流程、发热量测定方法、发热量赋值方法、能量计算方法、能量单位和计费方式6个方面提出能量计量的总体实施方案,从而为省内其他燃气企业实施能量计量提供参考与借鉴。