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971.
首先对阿克苏断层氢气浓度观测资料的周期成分进行了时频分析,然后分别利用线性回归和互相关方法分析了气温、气压与氢气浓度年周期成分的关系,并利用Molchan图表法对阿克苏断层氢气的映震效能进行了定量检验。结果显示:① 阿克苏断层氢气浓度具有清晰的年周期和半日周期成分;② 阿克苏断层氢气浓度的年周期动态变化与气温具有显著的正相关性,与气压的相关性一般,表明其年周期变化主要受气温影响;③ 阿克苏断层氢气浓度异常对观测点周边中强以上地震的反应较灵敏,映震效果较好。 相似文献
972.
The traditional data envelopment analysis(DEA), bootstrap-DEA and Malmquist models are employed to measure different tourism efficiencies and their spatial characteristics of 61 cities in six coastal urban agglomerations in eastern China. The following conclusions are drawn.(1) The comprehensive efficiency(CE) of urban tourism using the bootstrap-DEA model is lower than the CE level using the DEA-CRS model, which confirms the significant tendency of the DEA-CRS model to overestimate results.(2) The geometric CE averages of urban tourism in the Yangtze River Delta(YRD) and the Pearl River Delta(PRD) have changed from ineffective to effective since 2000, the averages in the Beijing-TianjinHebei(BTH) and the Shandong Peninsula(SDP) have changed from ineffective to moderately effective since 2000, and those in the Central and Southern Liaoning(CSL) and the West Bank of Taiwan Strait(WBTS) have been ineffective since 2000.(3) The CE values of urban tourism in the PRD, the YRD, the BTH and the SDP have been slightly affected by the pure technical efficiency(PTE), whereas the CE values in the CSL and the WBTS have been slightly affected by the scale efficiency(SE) since 2000.(4) Spatially, the range of geometric averages of the total factor productivity(TFP) for the PRD, the YRD, the BTH, the SDP, the WBTS and the CSL has decreased sequentially, while the one for most cities in six urban agglomerations has exhibited a downward trend since 2000.(5) Collectively, the natural conditions, the economic policies and the tourism capital drive the SE change of urban tourism of the CSL and the WBTS. The tourism enterprises for increasing returns to scale and imitating innovative technology have an effect on the CE change of urban tourism in the BTH and the SDP. The tourism market competition drives the PTE change of urban tourism in the PRD and the YRD. Although the PTE and the SE of urban tourism in six coastal urban agglomerations suffer from uncertain events, the CE maintained overall sound momentum since 2000. 相似文献
973.
广东地区雷电活动的气候分布特征 总被引:27,自引:14,他引:27
利用地闪定向仪(DF)和时间到达法(TOA)定位技术,1997年3月~1998年6月在研究范围内共计得到404431次地闪资料.分析了地闪的雷电流强度、回击数的气候概率分布特征以及雷电参数的日变化及其空间分布的气候规律.正闪占总闪的比例仅为5.03%,正负闪密度的高值中心均在(114.E,23.N)附近.总体日变化特征明显,全天有两个高值时段,分别为00~06时和12~18时.与北方地区的雷电特征不同.结果表明雷电活动特征可以基本揭示本地区天气活动的时空分布的规律. 相似文献
974.
975.
Chuan‐Chi Chien Ying‐Pin Huang Wie‐Chieh Wang Jun‐Hsing Chao Yuan‐Yao Wei 《洁净——土壤、空气、水》2011,39(2):103-108
Preventing radioactive pollution is a troublesome problem but an urgent concern worldwide because radioactive substances cause serious health‐related hazards to human being. The adsorption method has been used for many years to concentrate and remove radioactive pollutants; selecting an adequate adsorbent is the key to the success of an adsorption‐based pollution abatement system. In Taiwan, all nuclear power plants use activated carbon as the adsorbent to treat radiation‐contaminated air emission. The activated carbon is entirely imported; its price and manufacturing technology are entirely controlled by international companies. Taiwan is rich in bamboo, which is one of the raw materials for high‐quality activated carbon. Thus, a less costly activated carbon with the same or even better adsorptive capability as the imported adsorbent can be made from bamboo. The objective of this research is to confirm the adsorptive characteristics and efficiency of the activated carbon made of Taiwan native bamboo for removing 131I gas from air in the laboratory. The study was conducted using new activated carbon module assembled for treating 131I‐contaminated air. The laboratory results reveal that the 131I removal efficiency for a single‐pass module is as high as 70%, and the overall efficiency is 100% for four single‐pass modules operated in series. The bamboo charcoal and bamboo activated carbon have suitable functional groups for adsorbing 131I and they have greater adsorption capacities than commercial activated carbons. Main mechanism is for trapping of radioiodine on impregnated charcoal, as a result of surface oxidation. When volatile radioiodine is trapped by potassium iodide‐impregnated bamboo charcoal, the iodo‐compound is first adsorbed on the charcoal surface, and then migrates to iodide ion sites where isotope exchange occurs. 相似文献
976.
铁塔避雷针防雷检测跟踪验收应该注意一些问题 总被引:1,自引:1,他引:0
介绍铁塔避雷针在防雷检测验收应注意的一些主要问题。 相似文献
977.
978.
979.
阻碍网络GIS性能的因素分为两大方面:硬件环境和软件环境。聚焦于软件环境,从通用网络GIS的三层体系架构上入手,分别在数据层、逻辑层和层间数据传输上描述了的一些可实施的优化途径及其技术原理,以综合应用来提高网络GIS的效率。 相似文献
980.
随着鄂北大牛地气田的持续建产,水平井规模开发已成为气田开发的重点技术。但在水平井施工中,由于诸如地层岩性变化,可钻性差异大问题;泥岩稳定性问题;低破裂压力层段地层漏失问题等;钻井液润滑性和携岩性能和岩屑床清除问题;以及地层变化、尖灭使得突然钻遇泥岩、煤层,发生坍塌、掉块等不可控因素,对水平井钻井提速提效产生不利影响和困难。本文分析了影响水平井提速提效的瓶颈问题,提出较为完善的技术方案,从而实现水平井施工安全、快速、高效钻进的目的。 相似文献