江西省茶叶气象灾害风险评价

气象灾害是制约茶叶安全生产重要因素之一。为提升江西茶叶防灾减灾和生产气象服务保障能力,本研究基于江西省80个气象站1961—2016年的逐日气象数据和农业统计资料,根据自然灾害风险形成机制,考虑致灾因子、孕灾环境和承灾体,筛选出6个风险评价指标,建立江西省茶叶气象灾害风险评估模型,将江西省茶叶气象灾害风险划分为高风险、中风险、低风险和无风险4个等级。结果表明,江西省茶叶气象灾害综合高风险区主要位于上饶北部、九江西部、吉安西南部和赣州上犹县;中风险区主要位于江西西北部、赣州北部、抚州北部及宜春东部;低风险区主要位于江西中部和南部;无风险区主要位于江西中北部、西南部和新余市。研究结果可为茶叶防灾减灾管理和合理优化茶叶种植生产布局提供可靠的气象科学依据。     

以色列重技术创新发展风电

<正>据报道以色列能源部发起一个绘制风电发展潜力图的研究项目,由气象服务中心(IMS)执行,芬兰气象研究机构(FM)提供咨询,主要通过百米分辨率评估系统,绘出不同高度下风力的相关数据。     

长江三峡新一代水电气象服务体系设计

从分析长江三峡水电气象服务需求入手,依托新成立的长江流域气象中心及其各成员单位相关气象业务机构,整合长江流域气象服务技术资源,提出了开放、合作、共赢的长江三峡水电气象服务组织体系及其运行机制,从长江全流域视角出发,规划设计了由长江三峡水电气象预测预报系统、水电安全运行气象保障服务系统、水电气象服务基础支撑系统、水电气象服务科技创新与基础研究等四大功能模块构成的长江三峡新一代水电气象服务业务体系,为长江流域防汛抗旱与科学补水、水电工程综合开发、三峡工程高效运行、新能源开发与利用等提供全面、准确、及时的气象服务。     

基于WebGIS技术的专业气象服务网站业务系统

针对专业气象服务薄弱环节,基于WebGIS技术设计开发了专业气象服务网站业务系统,介绍了系统结构框架、数据信息与业务工作流程及各种功能和关键技术.该网站联网运行后,可视化、安全性有了较大提升,显著提高了业务系统的技术水平与支持能力.     

三峡水库梯级调度专业气象服务业务系统

针对大型水利枢纽工程因涉及地域广阔、水文条件复杂而导致气象信息服务系统建设难的问题,以三峡水库梯级调度专业气象服务业务系统为例,介绍了水库梯级调度气象保障服务系统的结构和实施方案.构建了梯级水库调度气象保障服务的业务工作体系,提出了框架结构更趋完整、数据流程更合理、各子系统间功能界面更清晰、充分体现气象与水文相结合的总体设计方案.该系统自动化程度高、预报模型先进、预报效果明显,应用效果显著,可为开发和建设同类水电行业专业气象服务业务系统提供实际经验和技术借鉴.     

西江流域水文气象综合干旱评价

综合分析气象干旱与水文干旱事件,可同时解析大规模干旱和供水风险,为综合识别旱情和早期干旱预警提供支持.利用1981～2013年西江流域集水区域逐月降水与流量资料,基于标准化降水指数和标准化流量指数构建水文气象干旱综合指标及其状态转移参量,并结合马尔科夫链模型研究流域水文气象综合干旱.结果表明,研究区水文干旱与气象干旱存...     

支持向量机方法在太阳辐射计算中的应用

利用郑州1961～2000年的逐月曝辐量和有关气象数据,分析了曝辐量与气象因子的相关关系,应用支持向量机(SVM)方法,确定了影响逐月曝辐量的主要气象因子,建立了月曝辐量的支持向量机计算模型,为太阳能资源的评估方法提供了一种新的技术方法。用1961～2000年的逐月资料对郑州气象站的逐月曝辐量进行训练建模,用2001～2006的资料做评估效果检验,研究结果证明该方法适用于曝辐量的计算和太阳能资源的评估,可应用于同一气候区内无辐射观测的气象台站曝辐量的计算和太阳能资源评估,也可根据月气候预测进行月曝辐量的预估。     

基于小波包与LSSVM的短期光伏输出功率预测研究

由于太阳辐照度及其他气象会随时发生变化,导致光伏电站输出功率具有可变性和不确定性,这将会对电网的安全运行造成重大影响。文章研究了影响光伏电站输出功率的几种气象因素,提出了一种基于小波包与最小二乘支持向量机(LSSVM)的短期光伏电站输出功率预测方法。首先,利用小波包将原始光伏电站输出功率,以及太阳辐照度、环境温度、环境湿度等气象因素进行分解,得到基频信号和多层高频信号;然后,利用最小二乘支持向量机所具有的处理小样本数据和解决非线性函数的能力,将得到的基频信号和多层高频信号作为最小二乘支持向量机的输入变量;最后,将不同尺度的输出结果进行叠加、合成,得到原始光伏电站输出功率的预测值。仿真结果表明,与传统的最小二乘支持向量机预测法、BP神经网络预测法,以及EMD与LSSVM相结合的预测方法相比,文章预测方法的预测精度较高,可以有效地预测光伏电站输出功率。     

基于CORBA的电子商务系统的安全性

电子商务使用了刊登广告并出售货物的新方法来进行交易，并为动态开放式电子 商务环境中的大组客户提供服务和信息。本文说明了实现电子商务应用程序所用的技术，该技 术集中于 CORBA 框架对于这些解决方案的支持。     

鄱阳湖生态系统服务功能状况评价模型及应用

为准确评价鄱阳湖生态系统服务功能状况,应用层次分析法和模糊评价法构建生态系统服务功能状况评价模型,对2010~2014年鄱阳湖生态系统服务功能状况进行评价。结果表明,供给服务、调节服务、文化服务和支持服务权重分别为0.121 9、0.263 3、0.056 9、0.557 9;2010~2014年鄱阳湖生态系统服务功能状况综合评价指数分别为0.723、0.732、0.731、0.710、0.682,评价等级均为良,2011~2014年整体呈下降趋势,一定程度上表明鄱阳湖生态系统服务功能正在退化;供给服务、调节服务和支持服务是影响鄱阳湖生态系统服务功能状况的因素,其中调节服务功能状况既是影响鄱阳湖生态系统服务功能状况的最主要因素,又是导致近年来鄱阳湖生态系统服务功能下降的主要原因,主要受湖泊天然调洪能力和水功能区水质达标率影响。研究结果为湖泊生态系统服务功能评价提供技术支撑。     

Ash-forming elements in four Scandinavian wood species. Part 1: Summer harvest

Woody biomass in Finland and Sweden comprises mainly four wood species: spruce, pine, birch and aspen. To study the ash, which may cause problems for the combustion device, one tree of each species were cut down and prepared for comparisons with fuel samples. Well-defined samples of wood, bark and foliage were analyzed on 11 ash-forming elements: Si, Al, Fe, Ca, Mg, Mn, Na, K, P, S and Cl. The ash content in the wood tissues (0.2–0.7%) was low compared to the ash content in the bark tissues (1.9–6.4%) and the foliage (2.4–7.7%). The woods’ content of ash-forming elements was consequently low; the highest contents were of Ca (410–1340 ppm) and K (200–1310), followed by Mg (70–290), Mn (15–240) and P (0–350). Present in the wood was also Si (50–190), S (50–200) and Cl (30–110). The bark tissues showed much higher element contents; Ca (4800–19,100 ppm) and K (1600–6400) were the dominating elements, followed by Mg (210–2400), P (210–1200), Mn (110–1100) and S (310–750), but the Cl contents (40–330) were only moderately higher in the bark than in the wood. The young foliage (shoots and deciduous leaves) had the highest K (7100–25,000 ppm), P (1600–5300) and S (1100–2600) contents of all tissues, while the shoots of spruce had the highest Cl contents (820–1360) and its needles the highest Si content (5000–11,300). This paper presented a new approach in fuel characterization: the method excludes the presence of impurities, and focus on different categories of plant tissues. This made it possible to discuss the contents of ash element in a wide spectrum of fuel-types, which are of large importance for the energy production in Finland and Sweden.     

NEXT GENERATION ENGINEERED MATERIALS FOR ULTRA SUPERCRITICAL STEAM TURBINES

正1 ABSTRACT To reduce the effect of global warming on our climate,the levels of CO2emissions should be reduced.One way to do this is to increase the efficiency of electricity production from fossil fuels.This will in turn reduce the amount of CO2emissions for a given power output.Using US practice for efficiency calculations,then a move from a typical US plant running at 37%efficiency to a 760℃/38.5 MPa(1 400/5 580 psi)plant running at 48%efficiency would reduce CO2emissions by 170kg/MW.hr or 25%.     

Aerodynamic performance effects of leading-edge geometry in gas-turbine blades

The purpose of this paper is to illustrate the advantages of the direct surface-curvature distribution blade-design method, originally proposed by Korakianitis, for the leading-edge design of turbine blades, and by extension for other types of airfoil shapes. The leading edge shape is critical in the blade design process, and it is quite difficult to completely control with inverse, semi-inverse or other direct-design methods. The blade-design method is briefly reviewed, and then the effort is concentrated on smoothly blending the leading edge shape (circle or ellipse, etc.) with the main part of the blade surface, in a manner that avoids leading-edge flow-disturbance and flow-separation regions. Specifically in the leading edge region we return to the second-order (parabolic) construction line coupled with a revised smoothing equation between the leading-edge shape and the main part of the blade. The Hodson–Dominy blade has been used as an example to show the ability of this blade-design method to remove leading-edge separation bubbles in gas turbine blades and other airfoil shapes that have very sharp changes in curvature near the leading edge. An additional gas turbine blade example has been used to illustrate the ability of this method to design leading edge shapes that avoid leading-edge separation bubbles at off-design conditions. This gas turbine blade example has inlet flow angle 0°, outlet flow angle −64.3°, and tangential lift coefficient 1.045, in a region of parameters where the leading edge shape is critical for the overall blade performance. Computed results at incidences of −10°,   −5°,   +5°,   +10° are used to illustrate the complete removal of leading edge flow-disturbance regions, thus minimizing the possibility of leading-edge separation bubbles, while concurrently minimizing the stagnation pressure drop from inlet to outlet. These results using two difficult example cases of leading edge geometries illustrate the superiority and utility of this blade-design method when compared with other direct or inverse blade-design methods.     

Hydrogen production by steam-gasification of carbonaceous materials using concentrated solar energy – V. Reactor modeling,optimization, and scale-up

A chemical reactor for the steam-gasification of carbonaceous particles (e.g. coal, coke) is considered for using concentrated solar radiation as the energy source of high-temperature process heat. A two-phase reactor model that couples radiative, convective, and conductive heat transfer to the chemical kinetics is applied to optimize the reactor geometrical configuration and operational parameters (feedstock's initial particle size, feeding rates, and solar power input) for maximum reaction extent and solar-to-chemical energy conversion efficiency of a 5 kW prototype reactor and its scale-up to 300 kW. For the 300 kW reactor, complete reaction extent is predicted for an initial feedstock particle size up to 35 μm at residence times of less than 10 s and peak temperatures of 1818 K, yielding high-quality syngas with a calorific content that has been solar-upgraded by 19% over that of the petcoke gasified.     

Contents in Volume 23,2014

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汽轮机数字电液调节系统挂闸异常的技术完善

分析了200MW汽轮机数字电液调节系统在运行中存在的挂闸异常问题,采取了相应的技术处理措施,且运行实践效果良好。     

新型高压共轨ECU升压模块的数字化开发与优化

为了提高喷油器电磁阀的响应速率,提出了一种基于CPLD(复杂可编程逻辑器件)应用于高压共轨ECU的数字升压模块。鉴于该升压电路结构参数多,其升压电压的恢复响应要求高等特征,基于Pspice建立了升压电路的仿真模型,研究了不同电路参数下升压模块的输出特性,全面优化了该升压模块的性能。结果显示,该升压模块的最大转换效率可以达90%以上。在柴油发动机上对ECU的试验表明,升压电压最大波动不超过10%,其恢复时间仅为1.3ms,功率管最大温升仅为41℃,满足整机运行范围内ECU的需求。     

Trace metal chemistry and silicification of microorganisms in geothermal sinter, Taupo Volcanic Zone, New Zealand

As part of a pilot study investigating the role of microorganisms in the immobilisation of As, Sb, B, Tl and Hg, the inorganic geochemistry of seven different active sinter deposits and their contact fluids were characterised. A comprehensive series of sequential extractions for a suite of trace elements was carried out on siliceous sinter and a mixed silica-carbonate sinter. The extractions showed whether metals were loosely exchangeable or bound to carbonate, oxide, organic or crystalline fractions. Hyperthermophilic microbial communities associated with sinters deposited from high temperature (92–94°C) fluids at a variety of geothermal sources were investigated using SEM. The rapidity and style of silicification of the hyperthermophiles can be correlated with the dissolved silica content of the fluid. Although high concentrations of Hg and Tl were found associated with the organic fraction of the sinters, there was no evidence to suggest that any of the heavy metals were associated preferentially with the hyperthermophiles at the high temperature (92–94°C) ends of the terrestrial thermal spring ecosystems studied.     

Assessment methods of material ageing using Sdobyrev''s creep rupture model

The physical aspects of the activation energy, in higher and high temperatures, of the metal creep process were examined. The research results of creep-rupture in a uniaxial stress state and the criterion of creep-rupture in biaxial stress states, at two temperatures, are then presented. For these studies creep-rupture, taking case iron as an example the energy and pseudoenergy activation was determined. For complex stress states the criterion of creep-rupture was taken to be Sdobyrev's, i.e. σ_red = σ₁ β + (1 − β)σ_i, where: σ₁-maximal principal stress, σ_i-stress intensity, β-material constant (at variable temperature β = β(T)). The methods of assessment of the material ageing grade are given in percentages of ageing of new material in the following mechanical properties: 1) creep strength in uniaxial stress state, 2) activation energy in uniaxial stress state, 3) criterion creep strength in complex stress states, 4) activation pseudoenergy in complex stress states. The methods 1) and 3) are the relatively simplest because they result from experimental investigations only at nominal temperature of the structure work, however, for methods 2) and 4) it is necessary to perform the experimental investigations at least at two temperatures.     

Production of hydrogen from sewage biosolids in a continuously fed bioreactor: Effect of hydraulic retention time and sparging

Hydrogen was produced from primary sewage biosolids via mesophilic anaerobic fermentation in a continuously fed bioreactor. Prior to fermentation the sewage biosolids were heated to 70 °C for 1 h to inactivate methanogens and during fermentation a cellulose degrading enzyme was added to improve substrate availability. Hydraulic retention times (HRT) of 18, 24, 36 and 48 h were evaluated for the duration of hydrogen production. Without sparging a hydraulic retention time of 24 h resulted in the longest period of hydrogen production (3 days), during which a hydrogen yield of 21.9 L H₂ kg⁻¹ VS added to the bioreactor was achieved. Methods of preventing the decline of hydrogen production during continuous fermentation were evaluated. Of the techniques evaluated using nitrogen gas to sparge the bioreactor contents proved to be more effective than flushing just the headspace of the bioreactor. Sparging at 0.06 L L min⁻¹ successfully prevented a decline in hydrogen production and resulted in a yield of 27.0  L H₂ kg⁻¹ VS added, over a period of greater than 12 days or 12 HRT. The use of sparging also delayed the build up of acetic acid in the bioreactor, suggesting that it serves to inhibit homoacetogenesis and thus maintain hydrogen production.