基于BP神经网络的非煤地下矿山安全评价模型

针对非煤地下矿山安全评价的复杂性和非线性特性,BP神经网络对非线性动态系统较强的适应性,提出并建立了一种基于BP神经网络的非煤地下矿山安全评价模型。为提高该模型的可靠性,结合非煤地下矿山生产工艺特点,提出了一套便于统计和赋值的安全评价指标体系;确定了BP神经网络结构和评价结果表征方法;为提高BP神经网络算法的收敛速度和稳定性,对标准BP算法进行有效改进;通过实例运算验证了该模型的可行性。基于BP神经网络的安全评价模型为评价非煤地下矿山安全管理现状及水平提供了可操作的方法,为矿山有关部门提供了科学安全管理的依据。     

Numerical Investigation of Boundary-Layer Evolution and Nocturnal Low-Level Jets: Local versus Non-Local PBL Schemes

Numerical simulations of the evolution of the planetary boundary layer (PBL) and nocturnal low-level jets (LLJ) have been carried out using MM5 (version 3.3) with four-dimensional data assimilation (FDDA) for a high pollution episode in the northeastern United States during July 15–20, 1999. In this paper, we assess the impact of different parameterizations on the PBL evolution with two schemes: the Blackadar PBL, a hybrid local (stable regime) and non-local (convective regime) mixing scheme; and the Gayno–Seaman PBL, a turbulent kinetic energy (TKE)-based eddy diffusion scheme. No FDDA was applied within the PBL to evaluate the ability of the two schemes to reproduce the PBL structure and its temporal variation. The restriction of the application of FDDA to the atmosphere above the PBL or the lowest 8 model levels, whichever is higher, has significantly improved the predicted strength and timing of the LLJ during the night. A systematic analysis of the PBL evolution has been performed for the primary meteorological fields (temperature, specific humidity, horizontal winds) and for the derived parameters such as the PBL height, virtual potential temperature, relative humidity, and cloud cover fraction. There are substantial differences between the PBL structures and evolutions simulated by these two different schemes. The model results were compared with independent observations (that were not used in FDDA) measured by aircraft, RASS and wind profiler, lidar, and tethered balloon platforms during the summer of 1999 as part of the NorthEast Oxidant and Particle Study (NE-OPS). The observations tend to support the non-local mixing mechanism better than the layer-to-layer eddy diffusion in the convective PBL.     

Modified grey model for estimating traffic tunnel air quality

This study compared three forecasting models based on the mean absolute percentage errors (MAPE) of their accuracy in forecasting air pollution in a traffic tunnel: the Grey model (GM), the combination model used four sample point and five sample point prediction with GM (1,1)(GM(1,1)^4 + 5), and the modified grey model (MGM). An MGM was combined using the four points of the original sequence using the original grey prediction GM (1,1) for short-term forecasting. The proposed method cannot only enhance the prediction accuracy of the original grey model, but can also solve the jump data forecasting problem something for which the original grey model is inappropriate. The MAPE was applied to the models, and the MGM found the proposed method to be simple and efficient. The MAPE of MGM, calculated over 3 h of forecasts, were as follows: 10.12 (Upwind), 10.07 (Middle) and 7.68 (Downwind) for CO; 10.79 (Upwind), 6.05 (Middle) and 5.98 (Downwind) for NO _x , and 11.67 (Upwind), 7.32 (Middle) and 4.56 (Downwind) for NMHC. The MGM model results reveal that the combined forecasts can significantly decrease the overall forecasting error. Results of this demonstrate that MGM can accurately forecast air pollution in the Kaohsiung Chung–Cheng Tunnel.     

BOD5 Estimation by Using UV Absorption and COD for Rapid Industrial Effluent Monitoring

The study dealt with the method to predict the BOD₅ in effluent from industrial wastewater by using the UV absorption from two wavelengths, 260 and 550 nm. The interference from suspended solids was reduced. In the same time, COD was used as the secure value to calculate BOD₅. From the representative wastewater treatment plants, the estimated effluent BOD₅ of wastewater from the Para rubber industry showed an average error at ±2.97 mg/l. While it was at ±3.31 mg/l, for frozen seafood industry. The simple mathematic equations in this study gave the assuring method for BOD₅ estimation without time consuming.     

HDNPTT与镉显色反应的研究

应用合成的新试剂 1- (2 -羟基 - 3 ,5 -二硝基苯 ) - 3 - (4 -苯基 - 2 -噻唑 ) -三氮烯 (HDNPTT) ,研究了在表面活性剂TritonX - 10 0存在下 ,它与Cd2 的显色反应。结果表明 ,在 pH 8 0～ 10 0范围内 ,Cd2 与该试剂形成的配合物 ,其最大吸收峰位于 5 35nm处 ,摩尔吸光系数为 1 89× 10 5L·mol-1·cm-1。Cd2 在 0mg/L～ 0 32mg/L范围内符合比尔定律。此法用于环境水样和人发样品中微量镉的测定 ,结果满意。     

基于天气分型的北京地区雷电潜势预报预警系统

对1997-2006年457个雷暴过程的环流形势进行对比分析,将北京地区的雷暴天气分为东北低涡低槽、贝蒙低涡低槽、西来槽等11种雷暴天气型;利用南郊观象台(54511站)的探空资料计算对流有效位能、抬升指数和相对风暴螺旋度等33个对流参数,通过与北京地区SAFAIR3000获取的闪电定位资料进行统计分析,提取BCAPE、BLI、MDCI、BIC、KNEW和SWISS等6个对流参数作为北京地区潜势预报参数;采用事件概率回归(REEP)方法,利用获取的6个对流参数作为变量,形成了11种雷暴天气型下的潜势预报方法。利用WRF模式的预报场,建立适用于北京地区3～36 h雷电潜势预报系统。个例实验结果表明其具有较好准确性。由于该系统建立过程中使用了高分辨率探测资料和中尺度模式的输出结果,实现了雷电潜势预报由点到面,由粗到细的突破,对北京地区雷电预警预报具有一定的应用价值。     

MM5与CALMET对北京地区风能资源的初步模拟

利用MM5与CALMET模拟了北京地区10、30、50和70 m高度的风速和风功率密度分布,结果表明：各高度层风速与风功率密度的地域分布具有一致性,模拟的风速最大区位于门头沟西北部,而昌平西部、房山北部及延庆西部的风速次之,风速最小区位于顺义和东部城区;风功率密度的模拟显示京西地区和西北部地区的风资源较为丰富,北京东部、东南部和东北部及市区周边的风资源相对较小,开发潜力低。利用3座测风塔和3个气象站风速观测数据对模拟结果进行了初步检验,表明MM5与CALMET基本能模拟出风速的月变化和日变化特征,模拟和观测具有较好相关性,但模式存在对黄草梁和北梁地区模拟结果偏高、对涧沟地区模拟结果偏低的系统性误差,这可能与模拟区域地形复杂及模式自身分辨率不够等有关。     

西北地区能源-环境-经济可持续发展预警研究——以陕西省为例

能源、环境与经济是人类社会生存与发展的物质基础,能源经济发展在带来区域经济快速繁荣的同时,往往造成当地社会生活质量的下降和生态环境的破坏。陕西作为我国21世纪重要的能源接续地,在能源开发利用的同时也受到脆弱生态环境的约束,本文以此为例进行可持续发展预警实证研究具有一定的代表性和现实意义。通过设计能源-环境-经济可持续发展预警指标体系,构建出可持续发展预警模型,采用人工神经网络预警方法和层次分析法,编写出计算运行程序,运用Matlab7.1软件中人工神经网络工具箱,将有关数据信息和预警模型有机结合,探讨能源-环境-经济可持续发展理论构建与应用问题。研究结果表明:陕西能源-环境-经济的可持续发展趋势在2000-2014年间分别处于重警、中警、轻警和无警四种状态,基本符合陕西能源产业发展现状;所设计的预警指标能较好地反映出能源-环境-经济可持续发展的特征;基于BP人工神经网络的预警方法具有较强的仿真能力,能提高可持续发展预警的准确性,在能源产业可持续发展预警研究中具有一定的应用价值。     

近50年宁夏极端气温事件的变化研究

随着全球变暖,极端气候事件频繁发生,由此造成气象灾害的数量日益增加。深入研究极端气候的变化特征,能够为预测和预防极端事件灾害提供参考依据。采用线性倾向估计法、反距离加权法和R/S分析法,选取10个极端气温指标研究了宁夏近50年来极端气温事件的时空变化特征,并在此基础上尝试预测了未来该地区极端气温变化的情形。结果发现:全天极端高温天数、白天极端高温天数、夜间极端高温天数、生物生长季和夏季天数分别以0.76、0.48、0.67、0.35和0.29 d/a的趋势明显增加,而全天极端低温天数、白天极端低温天数、夜间极端低温天数和最大连续霜冻天数分别以-0.40、-0.25、-0.66和-0.30 d/a趋势显著减少,极端气温年较差也呈下降趋势(-0.02℃/a),且空间差异明显;除极端气温年较差外,其它各极端气温指标与年平均气温均有很好的相关性;年极端冷指标和极端气温年较差在未来将继续下降,极端暖指标在未来将继续上升;宁夏气象灾害所造成的影响和损失将进一步增大。     

Molecular characterization of soil bacteria antagonistic to Rhizoctonia solani,sheath blight of rice

Bacillus pumillus MTCC7615 has been identified as a potent isolate against Rhizocotonia solani, the fungal pathogen causing sheath blight in rice. The study aimed at probing the role of a 23kb size plasmid pJCP07 of Bacillus pumillus MTCC7615 in its fungal antagonism towards Rhizocotonia solani. Plasmid pJCP07 was found to be involved in production of a fungal antagonistic compound as demonstrated by plasmid curing and conjugational transfer experiments. Tn5 insertional studies further confirmed that the plasmid pJCP07 of Bacillus pumillus MTCC7615 carries some of the gene(s) involved in production of compound antagonistic to Rhizocotonia solani. The plasmid pJCP07 is thus a mobilizable medium-sized plasmid carrying genes responsible for antagonism of Bacillus pumillus MTCC7615 towards Rhizocotonia solani.