Terahertz band simulations using two different radiative transfer models     

Linjun PAN  Daren Lü 《中国科学:地球科学(英文版)》2018,61(10):1482-1490

A high-resolution dual-band terahertz (THz) radiometer was designed to measure vertical distributions of chemical elements in the middle atmosphere of the Tibetan Plateau. A forward simulation, which always should be conducted firstly for the development of a matching retrieval algorithm, has not been done before. We use two radiative transfer models, ARTS and AM, to simulate the water vapor, ozone and carbon monoxide spectra on the plateau based on the spectral design of the THz radiometer. The emission line characteristics of the three gases in this spectral band are identified. Reasons for the differences in the spectral simulations between the two models are analyzed for individual gases. The impact of several different spectral parameter settings on the simulations are evaluated through a series of sensitivity experiments. This study suggests that the ARTS is more suitable for the development of the THz radiometer retrieval algorithm. An optimal parameter setting of the ARTS for the three elements are given.  相似文献   

无磷条件诱导铜绿微囊藻(Microcystis aeruginosa)释放挥发性有机化合物对莱茵衣藻(Chlamydomonas reinhardtii)的影响     

杨王庭  赵静娴  徐庆欢  周律  甘丽平  左照江 《湖泊科学》2018,30(2):449-457

为了揭示磷(P)营养缺乏对蓝藻释放挥发性有机化合物(VOCs)的影响及其对其他藻类的化感作用,以形成蓝藻水华的主要种类铜绿微囊藻(Microcystis aeruginosa)为材料,在无P培养条件下对其释放的VOCs进行分析,同时测定VOCs对莱茵衣藻(Chlamydomonas reinhardtii)生长、光合色素含量和光合性能的影响.结果表明,采用无P培养基培养铜绿微囊藻24 h后,其释放的VOCs种类和含量均明显增加,与标准培养基培养相比,VOCs总释放量增加了73.4%,并出现7种新化合物.将铜绿微囊藻释放的VOCs通入莱茵衣藻溶液中,在标准培养基中铜绿微囊藻释放的VOCs对莱茵衣藻生长无显著影响,而无P条件下释放的VOCs则明显抑制莱茵衣藻生长,其响应指数(RI)为-0.25.此外,莱茵衣藻光合色素含量、光系统II(PSII)最大光化学量子产量(Fv/Fm)、有效光化学量子产量[Y(II)]、光化学淬灭系数(q P)和光合电子传递速率(ETR)也明显降低,而非光化学淬灭系数(NPQ)则明显升高,其RI为0.26.由此可见,蓝藻在富营养化水体中大量繁殖以及P自身沉降特性导致的P缺乏会促进蓝藻释放VOCs,同时这些VOCs在保持蓝藻营养竞争优势和水体藻类多样性减少中具有化感抑制作用.  相似文献   

Environmental impact of fluidized solidified silt casting on surrounding water bodies     

Yunquan Li  Silin Wu  Shi Shu  Yiyan Lv  Yan Cui 《Marine Georesources & Geotechnology》2020,38(5):604-610

Abstract

With the growing demand for underwater refill engineering, the construction technology of implementing fluidized solidification in underwater pouring has recently received increased attention. However, the environmental impact of underwater casting on surrounding water bodies, especially when the silt is polluted, is still unclear. In this study, a simulated underwater pouring test and a static immersion release test were conducted separately to study the quality of the surrounding water during and after pouring. The results showed that fluidized-solidified silt casting could increase the pH of the surrounding water, even after the pouring had stopped, by approximately 1.0 and the turbidity could reach 200 NTU. No diffusion of Zn and Cu into the surrounding water was observed and while Ni and Cr exhibited slight diffusion, this was at a level well below international water quality standard. During construction, reducing the distance from the seafloor to the bottom of the pouring catheter could reduce the level of pollution. After construction, the use of neutral solidified materials can effectively reduce the pH of the surrounding water and the potential risk of heavy metal dissolution.  相似文献   

Variance-covariance component estimation for structured errors-in-variables models with cross-covariances     

Lv  Zhipeng  Sui  Lifen 《Studia Geophysica et Geodaetica》2019,63(4):485-508

Studia Geophysica et Geodaetica - In this contribution, an iterative algorithm for variance-covariance component estimation based on the structured errors-in-variables (EIV) model is proposed. We...  相似文献   

Torsional dynamic response of a large‐diameter pipe pile in viscoelastic saturated soil     

Changjie Zheng  Hanlong Liu  Xuanming Ding  Yaru Lv 《国际地质力学数值与分析法杂志》2014,38(16):1724-1743

An analytical solution is developed in this paper to investigate the dynamic response of a large‐diameter end‐bearing pipe pile subjected to torsional loading in viscoelastic saturated soil. The wave propagation in saturated soil and pile are simulated by Biot's two‐phased linear theory and one‐dimensional elastic theory, respectively. The dynamic equilibrium equations of the outer soil, inner soil, and pile are established. The solutions for the outer and inner soils in frequency domain are obtained by Laplace transform technique and the separation of variables method. Then, the dynamic response of the pile is obtained on the basis of the perfect contacts between the pile and the outer soil as well as the inner soil. The results in this paper are compared with that of a solid pile in elastic saturated soil to verify the validity of the solution. Furthermore, the solution in this paper is compared with the classic plane strain solution to verify the solution further and check the accuracy of the plane strain solution. Numerical results are presented to analyze the vibration characteristics and illustrate the effect of the soil parameters and the geometry size of the pile on the complex impedance and velocity admittance of the pile head. Finally, the displacement of the soil at different depth and frequency is analyzed. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   

喜马拉雅东部三叠系涅如组地球化学和碎屑锆石U-Pb年代学特征及构造意义     

喻晓  吕新彪  曹华文 《矿物岩石》2021,41(3):95-108

喜马拉雅中—新生代地层沉积于印度被动大陆边缘,三叠系沉积物物源分析是冈瓦纳大陆裂解和古地理研究的重要载体.特提斯喜马拉雅东段上三叠统涅如组碎屑岩的物质来源和沉积背景具有较大的争议,本次研究采集隆子县斗玉乡晚三叠世粉砂质板岩进行碎屑锆石U-Pb年代学和全岩主微量元素地球化学分析.涅如组碎屑锆石年龄具有两个明显的峰值:206～224Ma(峰值213 Ma)和462～567Ma(峰值512 Ma),表明涅如组沉积时代为晚三叠世诺利期.涅如组w(SiO2)含量较低(平均值为57.7％),w(Al2O3)值较高(17.2％),轻稀土元素富集,重稀土元素亏损,轻稀土/重稀土元素平均值为8.1.高场强元素中Nb,Ta,Ti亏损,Zr,Hf,Th,U富集;大离子亲石元素中Ba,Sr亏损,Rb和K富集.综合分析认为源区岩石以酸性岩浆岩为主.本次研究认为上三叠统涅如组浊流相沉积形成于裂谷环境,代表新特提斯洋的打开;标志着拉萨板块从冈瓦纳大陆北缘裂解,并开始向北漂移.  相似文献   

Recent expansion of talus slopes in the northern Taihang Mountain Range,China: an example from the Xiaowutai Region     

Wu  Jialiang  Ma  Chao  Yang  Wentao  Lyu  Liqun  Miao  Lv 《Landslides》2021,18(9):3027-3040

Landslides - Talus slopes play an important role in landscape evolution in some mid-altitude mountains. In this study, we analyzed talus slope activity on Xiaowutai Mountain in the Northern Taihang...  相似文献   

Effect of the Dry Ashing Method on Cadmium Isotope Measurements in Soil and Plant Samples     

Wei‐Xin Lv  Hao‐Ming Yin  Meng‐Shu Liu  Fang Huang  Hui‐Min Yu 《Geostandards and Geoanalytical Research》2021,45(1):245-256

A dry ashing method is commonly used to remove organic material from samples prior to geochemical analysis. In the course of this study, the Cd isotope ratios of a series of soil and plant reference materials and samples were studied to evaluate the effect of the dry ashing method on measurement results of Cd isotope ratios. The samples were pre‐treated using the dry ashing method and high‐pressure bomb for comparison. The results show that the digestion using high‐pressure bombs did not lead to Cd loss, but using the dry ashing method would cause different proportions of Cd loss. The whole range of Cd isotope difference between two methods was from ?0.07‰ to 3.01‰. There was also an obvious difference in measured Cd isotope ratios from the same leaf sample pre‐treated independently by the dry ashing method, indicating that the amount of Cd loss and the effect on Cd isotope measurement during dry ashing is related to the properties of the samples. Therefore, dry ashing may not be appropriate for the removal of organic material in Cd isotope ratio measurement, especially for samples with high organic contents. The δ^114/110Cd values of reference materials NIST SRM 1573a and GSD‐30 are reported for the first time in this study.  相似文献   

Machine learning reveals the influences of grain morphology on grain crushing strength     

Wang  Yihan  Ma  Gang  Mei  Jiangzhou  Zou  Yuxiong  Zhang  Daren  Zhou  Wei  Cao  Xuexing 《Acta Geotechnica》2021,16(11):3617-3630

Acta Geotechnica - Grain morphology has significant impacts on the mechanical behaviors of granular materials. However, its influences on grain breakage are still poorly understood due to the...  相似文献   

广州市排水管道检测结果分析及修复技术选择     

赵巨尧  周律  安关峰  段木子  刘添俊  张洪斌  李思敏 《岩土钻凿工程》2011,(2):106-110

为确定适合广州市地下排水管道的修复方法,对广州老城区近100kin2地区进行调查。调查采用管道潜望镜（Quick View,QV）、管道闭路电视（closed—Circuit Television,CCTV）、管道声纳（Sonar）进行综合探测,结果表明,调查区域内的地下排水管道存在的主要问题是破损断裂、错位、路基下沉、管道淤塞现象,其中小直径管道的损坏情况较为严重,尤其是300mm的管道将近报废。针对地下排水管道的调查情况,结合现有修复技术的特点,经过对修复成本及施工的难易性的研究讨论,得出适合多种管道和缺陷类型的翻转内衬法（Cured In Place Pipe,CIPP）和施工要求相对简单的U型折叠法（U-fold）满足要求,并能够产生较高经济社会效益。  相似文献