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471.
为减少旅游业能源消耗,实现旅游低碳绿色发展,探讨如何提高旅游业能源效率,基于包含非期望产出的方向性距离函数,首先构建了适应旅游业的Biennial Malmquist-Luenberger(BML)效率指数,以中国30个省市2005~2013年旅游业为实证对象,测度了其能源效率,9 a来旅游业能源效率变化源泉可被分解为全要素生产率、资本对能源替代效应、劳动对能源替代效应、能源结构效应和产出结构效应5项影响因素。研究发现:(1)中国旅游业能源效率整体上处于较低水平,旅游业能源效率可以扩张提升的比例较大。(2)整体上全要素生产率、资本对能源替代效应、劳动对能源替代效应和能源结构效应的提升能促进旅游业能源效率提高。(3)近3 a来劳动和资本投入的能源替代效应对旅游业能源效率变化的作用超过了全要素生产率。(4)区域层面上,东部地区旅游业能源效率高于中西部地区,主要由地区间旅游业对资本投入使用和能源消耗结构的差异造成。(5)整个样本期间,中国17个省市旅游业能源效率呈现下降趋势,背后的因素各有不同,旅游业资本替代效应是湖北省、福建省和浙江省等多数省市旅游业能源效率下降的主要因素,全要素生产率是安徽省、海南省、贵州省和甘肃省旅游业能源效率下降的主要原因。因此,合理利用投入的资源要素对旅游业低能耗发展至关重要,尤其是要发挥好资本对能源的替代效应,高效的资本配置能极大提高旅游能源效率。 相似文献
472.
直流系统的稳定性影响着发电厂和变电站的安全运行,介绍了几种传统的直流系统接地故障检测方法,并分析了每种方法的优缺点。针对传统直流系统接地故障检测方法的不足,提出了一种基于改进电桥法的故障检测方法,通过两次投切检测电阻来检测电桥上的不平衡电流和支路漏电流,计算得出接地电阻并快速找出故障支路,通过对比分析发现改进电桥法的测量准确性更高。 相似文献
473.
矿井风险评价基本模型研究与探讨 总被引:6,自引:0,他引:6
提出风险的绝对值和相对值的概念,探讨了如何合成事故发生可能性和事故后果严重程度这两个指标,如何确定多个评价单元的评价对象的风险等级划分等问题。 相似文献
474.
孟文勇 《中国安全科学学报》1996,6(2):53-57
油气生产中的各种不安全因素大多来源于现场作业。生产现场是安全管理的控制点。运用安全管理和安全系统工程的一些理论方法,可以提高生产中人的安全意识,减少现场作业中的事故隐患,达到预防事故的目的 相似文献
475.
476.
477.
流场分布对电除尘性能至关重要。采用商业CFD软件,对某1 000 MW机组电除尘器进行了数值模拟。模拟过程中采用离散相模型(DPM)结合k-ε湍流模型,模拟颗粒运动轨迹。研究了在合理布置烟道走向,并在烟道内布置导流板、阻流板,在进口喇叭内布置气流分布板及导流叶片等措施条件下,电除尘器的气固两相流参数。结果表明:烟道内布置导流板及阻流板后,电除尘器各分室进口流量偏差均在±2%以内,出口流量偏差均不超过±0.5%,远优于标准要求;颗粒相质量流量分配偏差也均未超过5%,且各级粒径分布所对应偏差也明显减小;电除尘器各室入口截面烟气流速相对均方根差均不超过0.15,优于标准要求。 相似文献
478.
Occurrence and human dietary assessment of sulfonamide antibiotics in cultured fish around Tai Lake,China 总被引:1,自引:0,他引:1
Chao Song Le Li Cong Zhang Barry Kamira Liping Qiu Limin Fan Wei Wu Shunlong Meng Gengdong Hu Jiazhang Chen 《Environmental science and pollution research international》2017,24(21):17493-17499
As the most important fishery medicines, sulfonamides are widely used to prevent diseases caused by pathogens in aquaculture. However, relatively little is known about the residues and dietary risks associated with cultured fish around Tai Lake. In the present study, a sampling strategy for a complete aquaculture period was conducted. Specifically, 12 selected sulfonamide antibiotics were measured among 116 fish samples recruited from four sampling periods, four species, four areas, and 18 fish ponds. All 12 antibiotics were detected at detection frequencies of 4.31–28.45%. Total sulfonamides were detected in 77.59% of the fish samples, with 57.76% of fish samples containing from 0.1 to 10 μg kg?1. Sulfadiazine (SDZ), sulfamethoxazole (SMZ), sulfamethazine (SDD), and sulfamonomethoxine (SMM) were the main types of antibiotics used, and these were present at high concentrations (>100 μg kg?1) with high occurrences, especially in the middle of the aquaculture season. Dietary assessment showed that residual antibiotics in all fish that were being sent to market were far below the maximum residue limit (MRL) of total sulfonamides and that there was almost no risk associated with fish consumption. The results of the present study will facilitate development of effective measures to produce safe aquatic products and meaningful suggestions for consuming aquatic products. 相似文献
479.
Qing Yu Meng Dalia Spector Steven Colome Barbara Turpin 《Atmospheric environment (Oxford, England : 1994)》2009,43(36):5750-5758
Effects of physical/environmental factors on fine particle (PM2.5) exposure, outdoor-to-indoor transport and air exchange rate (AER) were examined. The fraction of ambient PM2.5 found indoors (FINF) and the fraction to which people are exposed (α) modify personal exposure to ambient PM2.5. Because FINF, α, and AER are infrequently measured, some have used air conditioning (AC) as a modifier of ambient PM2.5 exposure. We found no single variable that was a good predictor of AER. About 50% and 40% of the variation in FINF and α, respectively, was explained by AER and other activity variables. AER alone explained 36% and 24% of the variations in FINF and α, respectively. Each other predictor, including Central AC Operation, accounted for less than 4% of the variation. This highlights the importance of AER measurements to predict FINF and α. Evidence presented suggests that outdoor temperature and home ventilation features affect particle losses as well as AER, and the effects differ.Total personal exposures to PM2.5 mass/species were reconstructed using personal activity and microenvironmental methods, and compared to direct personal measurement. Outdoor concentration was the dominant predictor of (partial R2 = 30–70%) and the largest contributor to (20–90%) indoor and personal exposures for PM2.5 mass and most species. Several activities had a dramatic impact on personal PM2.5 mass/species exposures for the few study participants exposed to or engaged in them, including smoking and woodworking. Incorporating personal activities (in addition to outdoor PM2.5) improved the predictive power of the personal activity model for PM2.5 mass/species; more detailed information about personal activities and indoor sources is needed for further improvement (especially for Ca, K, OC). Adequate accounting for particle penetration and persistence indoors and for exposure to non-ambient sources could potentially increase the power of epidemiological analyses linking health effects to particulate exposures. 相似文献
480.
Li Xiaoping Cai Yue Liu Dongying Ai Yuwei Zhang Meng Gao Yu Zhang Yuchao Zhang Xu Yan Xiangyang Liu Bin Yu Hongtao Mielke Howard W. 《Environmental science and pollution research international》2019,26(6):5564-5576
Environmental Science and Pollution Research - Utilization of microbes is one of the most promising methods to remediate potentially toxic metals (PTMs) from soil. In this study, a systematic... 相似文献