近距离上层隧道施工对下层隧道的扰动影响          下载免费PDF全文

唐强森  刘涛 《地震工程学报》2018,40(3):591-596,603

针对近距离上层隧道施工时给下层隧道稳定性造成扰动影响的现状,基于简支土体梁力学模型,研究下层隧道顶部在周期性扰动力作用下的系统振动特性,得到顶部垂直位移的动态响应数学表达式,为定量掌握最大位移峰值的大小与出现时刻提供理论依据,指出考虑振动因素时上下层隧道安全距离的确定方法。结合具体算例探索扰动力等因素对最大位移的作用规律,结果表明:扰动力振幅和隧道跨度分别增加1倍和2倍时,最大位移峰值相应增大1倍和23.9倍;隧道层间垂距和土体弹性模量分别增加2倍和3倍时,最大位移峰值相应减小88.2%和70%。当主要影响因素变化时,最大位移的波动大周期延长、波动震荡性加剧,特别是峰值处的震荡幅值增大,隧道顶部稳定性受到明显影响。  相似文献   

印度尼西亚北苏拉威西红树林生态系统碳库研究     

陈顺洋  陈彬  SASTROSUWONDO Pramudji  DHARMAWAN I Wayan Ek  欧丹云  尹希杰  俞炜炜  陈光程 《海洋学报(英文版)》2018,37(12):85-91

近年来的研究指出红树林在海岸带碳固定和碳储存方面发挥着重要的作用。尽管印度尼西亚的红树林面积在全球占很大的比重，对于该地区红树林的有机碳储量和土壤有机碳来源的认识仍有限。本研究调查了印度尼西亚北苏拉威西海洋型的Wori红树林中生态系统有机碳储量及其空间分布特征，以及土壤有机碳的来源，以期加深该地区红树林“蓝碳”功能的认识。研究结果显示，Wori红树林0-50cm深度土壤中有机碳储量为15.4 kg/m²，占生态系统碳储量的主要部分（65%）。红树植物生物量和生态系统碳储量分别为8.3 kg/m²和23.7 kg/m²。土壤有机碳储量在不同离岸距离的采样站位中未表现出显著的空间分布差异，而生物量碳储量则在外滩最高。¹³C稳定同位素分析结果表明红树林土壤中蓄积的有机碳主要来源于红树林有机质，而潮水中的悬浮有机质和红树林外缘的海草并不构成红树林土壤有机碳的重要来源，它们的贡献者都低于20%。研究结果进一步证实了热带地区海洋型红树林湿地在碳储存以及红树植物对碳固定方面的重要性。  相似文献   

印度尼西亚北苏拉威西蓝碧海峡浮游动物种类组成及分布   总被引：1，自引：0，他引：1  

王彦国  陈小银  邢炳鹏  孙柔鑫  FITRIA Nurul  项鹏  王春光  林茂 《海洋学报(英文版)》2018,37(12):35-44

Based on oceanographic survey data in June 2012 in the Lembeh Strait, the zooplankton ecological characteristics such as species composition, individual abundance, dominant species and distribution were analyzed. The results showed that 183 species(including 4 sp.) had been recognized, most of them belonged to copepoda.Cnidaria followed with 43 species(including 1 sp.) were identified. The average abundance of zooplankton was(150.47±58.91) ind./m~3. As to the horizontal distribution, the abundance of the zooplankton was higher in the southern waters than in the northern waters. The dominant species in the study area were Lensia subtiloides,Sagitta enflata, Lucifer intermedius, Oikopleura rufescens, Diphyes chamissoni, Creseis acicula, Subeucalanus subcrassus, Temora discaudata, Aglaura hemistoma, Doliolum denticulatum, Canthocalanus pauper, Oikopleura longicauda and Nanomia bijuga. Zooplankton biodiversity indexes were higher in study area than previous study in the other regions. The findings from this study provide important baseline information for future research and monitoring programs.  相似文献   

太空搭载海水钝顶螺旋藻诱变株H_(11)的室外产多糖特性研究     

谭丽  李涛  吴华莲  吴嘉仪  向文洲  刘德海 《海洋通报》2018,(3):328-334

本研究对一株经太空搭载后选育的海水钝顶螺旋藻诱变株H_(11)的室外产多糖能力进行了评估。结果显示,在广州秋季室外平均温度为27°C下,诱变株H_(11)的生物量产率、总糖含量、总多糖含量和水溶性多糖含量分别为19.09±0.03 mg/(L·d)、27.89±1.28%DW、20.95±0.87%DW和19.74±0.93%DW。与野生株WT相比,H_(11)的生物量、总糖、总多糖和水溶性多糖的产率分别提高了15.39%,148.93%,176.50%和187.70%。在冬季室外平均培养温度为17°C条件下,诱变株和野生株生长速率及多糖产率都有所降低,但诱变株在产多糖能力上仍显著高于野生株(P0.05)。研究表明海水钝顶螺旋藻诱变株H_(11)产多糖能力极高,具有可观的产业应用前景。  相似文献   

海洋功能区划与海洋生态红线关系探讨          下载免费PDF全文

高月鑫  曾江宁  黄伟  陈全震  寿鹿  徐晓群 《海洋开发与管理》2018,35(1):33-39

海洋生态红线制度是我国"五位一体"文明建设的具体要求。为进一步在自然科学与人文科学的联结点上探求深入开展生态红线工作的可能性,文章对比了实施多年的海洋功能区划与历史新阶段提出的海洋生态保护红线的概念和内涵,剖析了两者之间的区别与联系,指出海洋功能区划与海洋生态红线区划在法律地位和管控制度等方面具有一致性,在划分目标、空间管理及划分方法上具有差异性,海洋功能区划以"使用"为主,海洋生态红线以"保护"引领。在此基础上,建议未来海洋生态红线工作的开展可从海洋功能区划借鉴经验,建立完善的管控评估制度,确立生态保护红线的优先地位,处理好海洋功能区划与海洋生态红线区划的关系。同时,海洋生态红线区划应以维持海洋生态系统结构稳定和提高海洋生态系统服务功能为目标,将区域资源环境承载力评估作为一项参考指标,限制低承载区的开发利用,保证海洋生态环境健康可持续发展。  相似文献   

3D P-WAVE VELOCITY STRUCTURE AT THE NORTHEASTERN MARGIN OF ORDOS BLOCK     

HAN Xiao-ming  Liu Fang  ZHANG Fan  CHEN Li-feng  LI Juan  LI Shuan-hu  YANG Hong-ying 《地震地质》2018,40(1):215-231

Using the 7 100 absolute first arrivals of P waves and 91 513 relative P arrival times of 726 events at the northeastern margin of the Ordos block since 2009, the 3D fine structure of P wave velocity within the depth of 15km in the crust was inverted by the double difference seismic tomography method. The results show that there exist obvious high-speed continuous bodies in the northwest of the study area, and their lateral areas increase gradually with depth, while the velocity of east and south is relatively low. The velocity inhomogeneity exists and differs at different depths. The lateral differences of velocity are related to seismicity and faults. The 5~15km depth profile shows that earthquakes tend to occur in the area with relatively high velocity or high speed transition zones, which to some extent reflects the fragility of regional crustal media and the strong differential movement of faults in vertical and horizontal directions where the crust body is easy to absorb and store strain energy and generate major earthquakes. A "Y"-shape low-velocity channel is present in the lower crust around Liangcheng, corresponding to the NW-trending Heilaoyao-Shahukou fault set, which may reveal the migration path of the Late Tertiary-Quaternary basalt eruption. The Helingeer M6.2 earthquake in 1976 was related to the formation of the locking section of the thermal welding in this area. The three-dimensional fine structure of P wave velocity presented in this paper provides intuitive seismological evidence for physical and chemical properties of crustal media and the deep tectonic environment of earthquake preparation.  相似文献   

A SYSTEM OF CAPACITIVE HIGH-VOLTAGE PULSE RECHARGE/DISCHARGE AND ITS IMPLICATION ON EXPERIMENTALLY TRIGGERED EARTHQUAKE     

ZHANG Zhi-he  GUO Yan-shuang  CHEN Shun-yun 《地震地质》2018,40(6):1417-1426

An external small disturbance may trigger seismic events when the fault is in a critical state. The problems related with earthquakes triggered by the dynamic stress such as blasting loads, impact loads, volcanic eruptions and strong earthquakes, have usually drawn wide concerns in earthquake science, and the corresponding research contents are quite extensive, including earthquake triggering mechanisms, triggering earthquake uncertainty, aftershock triggering, and so on. Among them, experimental research is an important way to understand the stress triggering conditions and physical mechanisms, such as the influence of load disturbance on fault friction traits, the influence of periodic disturbance of tidal stress on fault instability, etc., all of which can be gained through experimental investigations. Among them, "how to trigger" is a basic scientific problem to increase the understanding of earthquake prediction theory, thus receiving more attention. There are also some studies that focus on "what happened after the trigger", that is, the sliding instability generated by the triggering method, and then the evolution characteristics of the sliding instability process. The well-known experimental study of the super-shear rupture process is conducted by using the electric explosion method to trigger the fault instability, and the high-speed camera records the super-shear rupture during the fault instability. This means that when the trigger source is controllable, it is possible to generate different types of instability processes, and then to explore which earthquakes will be triggered at different time and space positions under different stress states by means of active triggering. The study of stability analysis and instability process has important scientific significance.A stable system of capacitive high-voltage pulse discharge and recharge is one of basic techniques for studying the triggered earthquakes in laboratory. Based on the wire electric explosion method, this paper develops a controllable trigger experiment system. By designing a new capacitive high-voltage pulse charge and discharge system, while considering the actual needs of monitoring and system timing, multiple functions are integrated into one system. Functionally, in addition to realizing the dynamic loading and unloading function of the wire electric explosion method, the discharge process can be monitored, and the triggering, synchronization and timing signal output is performed with other observation systems, thus realizing the whole process monitoring of the dynamic disturbance action. After testing, the following functions are achieved:1)The voltage and current of the high-voltage charging power supply system can be automatically adjusted, and the system can be shut off after charging; 2)Control modes include manual and remote controls. These two modes can control the recharge, release and pulse discharge of the high voltage capacitor; 3)The system can produce multi-channel synchronous output, which satisfy multiple systems working together. In particular, the remote sensing method greatly improves the experimental maneuverability and security; 4)The system has multiple sets of gas discharge tube to trigger discharge, with a wide range of discharge voltage of 500~5 000V; 5)Roche coil resistance integral current detection can meet the transient resistance, large current detection. Test results indicate that this system has good repeatability and stability with the same discharge energy and discharge energy regulator, which is conducive to carry out single channel trigger of high-pressure discharge experiment. In short, the new charging and discharging system can meet the requirements of experimental study of triggering earthquake. In addition, this system can be used to generate the stress disturbance under certain static and dynamic conditions, and then judge whether this kind of mechanical conditions in active fault systems is currently stable.In short, a controllable single-shot discharge system is developed by a capacitive high-voltage pulse discharge system, which provides a good technical basis for experimental research on triggering earthquakes. In addition, the new system also has application significance:1)multiple triggering output can simultaneously start multiple systems and improve the efficiency of observation. Fault instability is a characteristic of transient response, so, its observation requires high-speed acquisition equipment, which is difficult to control on observation; the trigger system is controllable, with active synchronization observation using physical parameters; 2)stress disturbance can be triggered under static and dynamic loads to detect the safety and stability of the fault system with active trigger.  相似文献   

Variation in soil saturated hydraulic conductivity along the hillslope of collapsing granite gullies   总被引：2，自引：0，他引：2  

Xiaoqian Duan  Yusong Deng  Yu Tao  Yangbo He  Lirong Lin 《水文科学杂志》2018,63(5):803-817

Saturated hydraulic conductivity (K_s) affects the soil hydrological process and is influenced by many factors that exhibit strong spatial variations. To accurately measure K_s and its scale, spatial variability and relationship with collapsing gullies, we analysed four double-ring infiltrometer diameters in three soil layers during in situ experiments designed to measure K_s in two typical collapsing gullies (three slope sites) in Tongcheng County of China. The results showed that K_s increased with increasing inner ring diameter, but no significant difference existed between inner diameters of 30 and 40 cm. The K_s in red soil layers was higher than that in sandy soil layers, the transition layers had the lowest values. K_s also varied with slope position, gradually decreasing with distance from the gully head. The suggestion is that the spatial variation in K_s is affected not only by the intrinsic soil properties but also by the interaction with the collapsing gully.  相似文献   

Total Synthesis of Marine Cyclic Enol-Phosphotriester Salinipostin Compounds     

ZHAO Mingliang  WEI Xianfeng  LIU Xuemeng  DONG Xueyang  YU Rilei  WAN Shengbiao  JIANG Tao 《中国海洋大学学报(英文版)》2018,(3)

Due to their structural diversity and variety of biological activities, marine natural products have been the subject of extensive study. These compounds, especially phospholipid polycyclic aromatic hydrocarbons, have a wide range of pharmacological applications, including embedded DNA and central nervous system, anti-tumor, anti-virus, anti-parasite, anti-bacterial, and antithrombotic effects. Unfortunately, the insufficient drug sources have limited the development of these compounds. In this study, we isolated salinpostin compounds from a fermentation solution of marine-derived Salinospora sp., which has a common bicyclic enol-phosphotriester core framework, as well as potent and selective antimalarial activities against P. falciparum with EC_(50)=50 nmolL~(-1). The chemical synthesis of these compounds in greater quantities is necessary for their use in bioactivity studies. Thus we explored a short route with high yields and mild reaction conditions, which can generate combinatorial libraries for drug discovery and lead optimization. We developed a new total synthesis method for six cyclic enol-phosphotriester salinipotin compounds and their diastereomers. For the total synthesis of cyclipostin P, we prepared cyclic enol-phosphotriester salinipostin compounds in 10 steps from a readily accessible starting material, 1,3-dihydroxyacetone, and obtained an overall yield of 1.29%. We fully characterized these compounds by proton nuclear magnetic resonance(~1H-NMR), carbon-13 NMR(~(13)C-NMR), and high-resolution mass spectrometry(HRMS) analyses, and found they coincide absolutely with the same compounds reported previously.  相似文献   

酶解法辅助提取布渣叶总黄酮的工艺优选          下载免费PDF全文

陈雪婷  徐文杰  李智勇 《应用海洋学学报》2018,34(10):176-179

目的：优选酶解法辅助提取布渣叶总黄酮的工艺条件。方法：以总黄酮提取率为指标，采用单因素试验、正交试验法，分别考察酶种类、酶用量、pH值、酶解时间及乙醇浓度对提取工艺的影响。结果：最佳工艺条件为复合酶（纤维素酶∶果胶酶=1∶1）用量1%，乙醇浓度60%，酶解1h，总黄酮提取率为20.90%，较未经酶解法提高了4.85%。结论：优选的工艺简单高效，为布渣叶总黄酮的开发利用提供了实验依据。  相似文献