湖泊污染底泥疏浚后新生沉积物-水界面溶解氧的动态响应

借助微氧电极测试技术对太湖贡湖湾试验区疏浚后的新生界面溶解氧动态进行一年的跟踪调研,分析溶解氧在新生微米级界面的分布特征、扩散通量以及界面附近有机质矿化速率.结果表明疏浚后半年内,溶解氧在表层沉积物的侵蚀深度增大,氧化层明显加厚.氧气在新生界面表层沉积物中呈指数下降,但衰减相对较缓.在连续一年的跟踪调查中发现,仅秋季新生界面附近溶解氧浓度明显高于对照,而在其他月份无差异.污染底泥疏浚后一个月内氧扩散通量及有机碳矿化速率下降最为明显,仅为疏浚前的13%,其他月份沉积物-水界面氧的扩散通量、氧气的消耗速率、有机碳的降解速率均有不同程度下降,疏浚后新生界面氧气交换速率下降以及由此导致的有机碳矿化过程变缓可能深刻影响界面生源要素的迁移过程.     

土地整治视角下乡村低碳更新研究——以浦东新区惠南镇桥北村为例

碳达峰碳中和背景下,将低碳目标融入到乡村更新进程,是土地整治研究的重要内容,也是我国实现“双碳”目标的必然选择。结合上海浦东新区惠南镇桥北村“田、林、产、水、路、文、村”各系统的现状分析,指出在土地整治视角下存在耕地保护与产业发展、低效用地减量化近远期落实、垃圾处置与乡村环境协调等三方面核心问题,据此提出产业在地化提质、空间复合化增效与资源循环化利用的低碳更新策略。同时以碳足迹测算成果的生态效益,并将其反馈至土地整治项目体系研究中,以期为低碳发展时期乡村更新提供工作准则与技术路径参考。     

用切贝雪夫多项式拟合GPS卫星精密坐标

在GPS观测值仿真、单点定位和相对定位中,都需要不断计算GPS卫星的坐标。通过实例对切贝雪夫多项式拟合GPS精密坐标的精度进行分析,并探讨拟合多项式阶数对拟合精度的影响。     

基于广义点摄影测量的后方交会与前方交会方法研究

广义点摄影测量将传统的点摄影测量和当代发展的线摄影测量以及无穷远点理论综合升华,将摄影测量中处理的物理意义上的点扩展到数学意义上的广义点.本文主要研究广义点摄影测量理论下的后方交会和前方交会解算方法.分析评价了不同控制线分布情况对后方交会精度的影响;依据前方交会原理,对闭合直线段和圆进行了三维重建,取得了良好的效果.     

A Study of the Impacts of the Spatial Differences in Climate Engineering Programs on the Extreme Intensities of High-Temperature Events in China Under A 1.5°C Temperature Control Target

Based on the daily maximum temperature data and average temperature data prediction for the period ranging from 2020 to 2099 under the scenario of BNU-ESM climate engineering (G4 test) and non-climate engineering (RCP4.5), the regional differences in the extreme high-temperature intensities in China during the implementation of climate engineering programs (2020 to 2069) and after the implementation of those programs (2070 to 2099) were analyzed using a Weibull Distribution Theory. The results indicated the following: (1) The results of this study’s comparison between the two scenarios had shown that climate engineering had not fundamentally changed the spatial features of the high and low differentiations for the extreme high-temperature intensities with the different recurrence periods in China. It was found that in both scenarios, the extreme high-temperature intensities were characterized by the spatial differentiations of low-temperature intensities on the Qinghai-Tibet Plateau, and high-temperature intensities in the eastern and northwestern region; (2) This study’s comparison results of the two scenarios had indicated that the climate engineering processes during the two study periods could potentially help mitigate the extreme high-temperature intensities with different recurrence periods in China. Furthermore, the mitigation effects during the implementation period would be significantly higher than those after the implementation; (3) This study’s results of the comparison between the periods ranging from 2020 to 2069 and 2070 to 2099 under the proposed climate engineering scenarios suggested that there would be no strong rebounding of the extreme high-temperatures following the implementation of climate engineering programs, and the mitigation effects on the extreme high-temperature intensities during the implementation of the climate engineering programs would be significantly higher than after the implementation of the programs; (4) When comparisons were made of the changes of the average temperatures in China before and after the implementation of climate engineering programs, the results had shown that the average temperature in China had been reduced by at least 1.25℃ as a result of climate engineering, which would effectively alleviate the global warming trend, and could also be conducive to the realization of a temperature control target of 1.5℃ in accordance with the Paris Agreement.     

一种中国南海海绵Xestospongia testudinaria中化学成分的研究

综合运用正相和反相硅胶柱层析、Sephadex LH-20凝胶柱层析以及制备HPLC等分离方法,从1种中国南海海绵Xestospongia testudinaria中追踪分离抗肿瘤活性次级代谢产物。从95%乙醇提取物中分离获得8个单体化合物,通过NMR,MS等波谱技术鉴定其结构分别为:E-18,18-二溴-9,17-二烯-5,7-二炔硬脂酸甲酯(1),E-18,18-二溴-9,17-二烯-5,7-二炔硬脂酸乙酯(2),麦角甾-5,7,22-三烯-3-醇(3),麦角甾-4,6,8(14),22-四烯-3-酮(4),胆甾-4-烯-3-酮(5),3-吲哚醛(6),3-吲哚酸(7)和5-吲哚醛(8)。其中,化合物2-5和8为首次从该属海绵中分离得到。化合物1对肿瘤细胞株HCT116和A549显示较强的抑制活性。     

影响北镇县玉米生产的主要气象灾害与防御对策

1 前言 北镇县地处医巫闾山东侧,地势地形复杂,属温带季风大陆性气候,无霜期为155～165天,农作物生长期日照充足,热量一茬有余,年平均降雨量为600mm,有利于农作物生长发育。但是,北镇县农业气象灾害频繁,多年来,农作物的生长和产量的形成都不同程度地受到农业气象灾害的影响。北镇县历年玉米播种面积30万亩左右,占粮食面积的40％。经多年研究     

金矿化局部预测中的真空爆裂法

真空爆裂法为温压地球化学方法的一种。所用样品为岩石。使用数字方法和计算技术整理测量结果及查明测量结果的意义。该法与其他温压地球化学方法的资料一起,可用于解决许多地质勘探中的实际问题。     

云南金顶铅锌矿床方铅矿溶解实验及紫外吸收光谱特征

在进行金顶铅锌矿床方铅矿溶解实验的基础上，测定并讨论溶解液的紫外吸收光谱特征，确定溶解液中铅的存在形式，进而初步探讨铅在含矿流体中的迁移形式。