湛江地区汛期降水稳定同位素的变化与水汽来源的关系          下载免费PDF全文

甘秋莹  范伶俐  陈汉森  李丽芳  李俊宇  郑侦明 《海洋气象学报》2021,41(1):129-137

以湛江降水为研究对象,利用收集的2019年汛期68个降水样品及同期气象资料,采用同位素示踪技术,结合HYSPLIT(Hybrid Single-Particle Lagrangian Integrated Trajectory)模式溯源,分析了湛江地区汛期降水稳定同位素的变化与水汽源地的关系,并对5个代表性的降水个例进...  相似文献   

改进的f-x域预测滤波及其应用   总被引：2，自引：1，他引：1  

彭真明  肖慈珣  王斌  朱文革  田光辉 《物探化探计算技术》1999,21(2):145-150

常规的ｆ－ｘ域预测滤波不仅理论上的假设比较苛刻,而且在分离随机噪音和有效信号时会引起信号畸变,降低输出剖面的保真效果和分辨率。本文对预测滤波器的各种误差来源和稳定性进行了分析,并提出了相应的改进措施。理论模型试算和实际资料处理结果表明,改进的ｆ－ｘ域预测滤波可以克服以上问题,使压制随机噪音的效果变好  相似文献   

Intraspecific diversity of Aureobasidium pullulans strains from different marine environments     

Jia Liu  Zhiqiang Liu  Zhenming Chi  Liang Zhang  Dechao Zhang 《中国海洋大学学报(英文版)》2009,8(3):241-246

Totally more than 500 yeast strains were isolated from seawater, sea sediments, mud of sea salterns, marine fish guts and marine algae. The results of routine and molecular biology identification methods show that nine strains among these marine yeasts belong to Aureobasidium pullulans, although the morphologies of their colonies are very different. The marine yeasts isolated from different marine environments indicate that A. pullulans is widely distributed in different environmental conditions. These Aureobasidium pullulans strains include A. pullulans 4#2, A. pullulans N13d, A. pullulans HN3-11, A. pullulans HN2-3, A. pullulans JHSc, A. pullulans HN4.7, A. pullulans HN5.3, A. pullulans HN6.2 and A. pullulans W13a. A. pullulans 4#2 could produce cellulase and single cell protein. A. pullulans N13d could produce protease, lipase, amylase and cellulase. Both A. pullulans HN3-11 and A. pullulans HN2-3 were able to produce protease, lipase and cellulase. A. pullulans JHSc could secrete cellulase and killer toxin. Both A. pullulans HN4.7 and A. pullulans HN5.3 could yield lipase and cellulase. A. pullulans W13a was able to secrete extracellular amylase and cellulase while A. pullulans HN4.7 and A. pullulans N13d could produce siderophores. This means that different A. pullulans strains from different marine environments have different physiological characteristics, which may be applied in many different biotechnological industries.  相似文献   

Screening of protease-producing marine yeasts for production of the bioactive peptides   总被引：1，自引：0，他引：1  

NI Xiumei  CHI Zhenming  LIU Zhiqiang  YUE Lixi 《海洋学报(英文版)》2008,27(2):116-125

Over 400 yeast strains from seawater and sediments were obtained, but only five strains named HN2 -3, N13d, N13C, Mb5 and HN3 - 2 among them could form clear zones around their colonies on the double plates with 2.0% casein. Peptides in the hydrolysate produced by the proteases from strains HN2 -3 and N13d had higher angiotensin I-converting-enzyme （ACE）-inhibitory activity. The two marine yeast strains were identified to be Aureobasidium pullulans according to the results of routine yeast identification and molecular methods. After purification of the proteases from the two marine yeast strains, it was found that the optimal pH for them was both 9.0, both of them were serine alkaline protease. However, the optimal temperature for the protease from the strain HN2 -3 was 52℃ while that from strain N13d was 48℃. ACE-inhibitory activity of the peptides in the hydrolysate of shrimp protein produced by the purified protease from the strain HN2 -3 was the highest while antioxidant activity in the hydrolysate of spirulina protein produced by the purified protease from the strain N13d was the highest.  相似文献   

Occurrence and diversity of <Emphasis Type="Italic">Pichia</Emphasis> spp. in marine environments     

Jing Li  Zhenming Chi  Xianghong Wang  Lin Wang  Jun Sheng  Fang Gong 《中国海洋大学学报(英文版)》2008,7(3):281-286

A total of 328 yeast strains from seawater, sediments, mud of salterns, the guts of marine fish and marine algae were obtained. The results of routine identification and molecular methods show that five yeast strains obtained in this study belonged to Pichia spp., including Pichia guilliermondii 1uv-small, Pichia ohmeri YF04d, Pichia fermentans YF12b, Pichia burtonii YF11A and Pichia anomala YF07b. Further studies revealed that Pichia anomala YF07b could produce killer toxin against pathogenic yeasts in crabs while Pichia guilliermondii 1uv-small could produce high activity of extracellular inulinase. It is advisable to test if Pichia ohmeri YF04d obtained in this study is related to central-venous-catheter-associated infection.  相似文献   

Impacts of forest structure on precipitation interception and run‐off generation in a semiarid region in northern China          下载免费PDF全文

Jiakai Liu  Zhenming Zhang  Mingxiang Zhang 《水文研究》2018,32(15):2362-2376

Water resource scarcity and uneven distribution are 2 major environmental issues in China today. Forest structure is a dominant factor that influences hydrological processes, but the specific interactions remain uncertain due to the predominant use of individual or 1‐dimensional forest structure metrics in previous studies. In this study, forest structures in 8 run‐off plots on Mount Miaofeng in north China were parameterized by metrics of different dimensionalities. The relation between canopy interception and forest structure, shrub/litter interception, and forest structure as well as run‐off and forest structure were analysed by regression method and validated by leave‐one‐out cross test. The results showed that canopy interception rates ranged from less than 0.10 all the way to 0.80, affected by forest structure and precipitation, with interception rate decreasing logarithmically as precipitation increased. Forests with a larger canopy area (CA), leaf area index (LAI), and higher average height (H) had a narrow range of canopy interception rates, and forest with larger value of diameters at breath height (DBH), H, LAI, vertical heterogeneity coefficient (T), and structure complexity index (SCI) had higher interception rates. Forests with higher value of DBH, H, and horizontal heterogeneity coefficient (R) had higher shrub/litter interception rates on the forest floor. The run‐off coefficient was only significantly associated with LAI, T, and SCI. The validation test indicated that regression analysis of canopy interception rates and shrub interception are reliable and SCI is a key factor to influence the run‐off coefficient. However, the regression results of litter interception have a relatively large error. According to the results, to reduce the risks of the landslides and floods, forest managers should complicate the canopy and preserve trees with thicker stems and larger canopies. By contrast, to obtain more water resource from run‐off in arid regions, forest managers should harvest trees with large canopies and construct complex vertical structures by intermediate cutting.  相似文献   

Simulation of carbonaceous aerosols over the Third Pole and adjacent regions: distribution,transportation, deposition,and climatic effects     

Zhenming Ji  Shichang Kang  Zhiyuan Cong  Qianggong Zhang  Tandong Yao 《Climate Dynamics》2015,45(9-10):2831-2846

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Seismic Hazard Assessment: Issues and Alternatives   总被引：3，自引：0，他引：3  

Zhenming Wang 《Pure and Applied Geophysics》2011,168(1-2):11-25

Seismic hazard and risk are two very important concepts in engineering design and other policy considerations. Although seismic hazard and risk have often been used interchangeably, they are fundamentally different. Furthermore, seismic risk is more important in engineering design and other policy considerations. Seismic hazard assessment is an effort by earth scientists to quantify seismic hazard and its associated uncertainty in time and space and to provide seismic hazard estimates for seismic risk assessment and other applications. Although seismic hazard assessment is more a scientific issue, it deserves special attention because of its significant implication to society. Two approaches, probabilistic seismic hazard analysis (PSHA) and deterministic seismic hazard analysis (DSHA), are commonly used for seismic hazard assessment. Although PSHA has been proclaimed as the best approach for seismic hazard assessment, it is scientifically flawed (i.e., the physics and mathematics that PSHA is based on are not valid). Use of PSHA could lead to either unsafe or overly conservative engineering design or public policy, each of which has dire consequences to society. On the other hand, DSHA is a viable approach for seismic hazard assessment even though it has been labeled as unreliable. The biggest drawback of DSHA is that the temporal characteristics (i.e., earthquake frequency of occurrence and the associated uncertainty) are often neglected. An alternative, seismic hazard analysis (SHA), utilizes earthquake science and statistics directly and provides a seismic hazard estimate that can be readily used for seismic risk assessment and other applications.  相似文献   

汶川Ms8.0级地震前后天气温度的异常变化     

赵振明  王亚强 《高原地震》2011,23(1):8-15

根据国内12个大中城市的12个气象站实际测量的2008年5月份31天的天气最低温度和最高温度共744个数据,结合曲线图对其特征进行对比研究,表明:①南宁市和广州市的低温,北京市和济南市的高温、低温,该月最低值都出现在5月12日汶川地震当天;②其他城市该月低温最低值出现的时间为:哈尔滨市9日,西宁市10日,西安市、郑州市...  相似文献   

侧限条件对振弦式应力计在混凝土应力量测中的影响性研究     

石振明  管圣功  陈锡锋 《工程地质学报》2011,19(4):487-491

通过在混凝土中直接埋设应力计和在量测区包裹橡皮泥后埋设应力计的对比试验,研究了振弦式钢筋应力计的侧限条件对混凝土应力测量结果的影响.试验结果表明:基于各截面上混凝土与应力计量测区钢筒的应变一致假定,振弦式应力计能较准确地测量混凝土的应力,但其测量值偏小;采用橡皮泥包裹应力计量测区的柔性侧向约束条件与应力计标定时的自由边...  相似文献