Development of GC capillary column for isomer-specific separation of toxic isomer of PCDDs and PCDFs in environmental samples

Analysis of polychlorinated dibenzo-p-dioxins (PCDD) and polychlorinated dibenzofurans (PCDF) has been performed using gas chromatography mass spectrometry (GC-MS). Analysis of the most toxic isomers, in particular, 2,3,7,8-substituted PCDD/PCDF in the presence of other isomers requires a special isomer specific capillary column or high performance liquid chromatography (HPLC) fractionation prior to GC-MS analysis. Commercially available long (>50 m) polar columns can separate 2,3,7,8-TCDD from other tetra isomers. However, those columns are not satisfactory for the analyses of total PCDD/PCDF in the environmental samples. Gas chromatography -high resolution mass spectrometry (GC-HRMS) and GC-MS/MS techniques are not helpful in the analysis of 2,3,7,8-TCDD unless it is separated from the other tetra isomers. The analysis of 2,3,7,8-TCDD and total PCDD and PCDF in a single GC-MS run can ease the laborious techniques presently used. In this study we have developed a new stationary phase for the GC capillary column. The capillary column developed using this new stationary phase showed unsurpassed selectivity for the separation of 2,3,7,8-TCDD from other tetra isomers. There are several advantages of the newly developed GC capillary column.     

染料结晶紫降解菌分离及其特性研究

从印染废水中筛选分离得到结晶紫（CV）降解菌株H，并对其脱色条件和机理进行了研究。结果表明，在外加生长基质条件下，菌株H不仅对CV降解脱色而且能降解中间产物。在pH7．0、35℃、摇床转速180r／min条件下，菌株H有最佳的脱色效果。对于20mg／L CV溶液，生长细胞降解0．5h，脱色率可达95％。休眠细胞对CV的降解规律也进行了对比探讨。菌株H对CV脱色过程遵循一级动力学方程，脱色速率常数k随CV浓度升高而降低，生长细胞的k值约为休眠细胞的6～7倍。     

细粒酒精模型冰的特征长度和变形模量

描述了细粒酒精模型冰特征长放和变形模量的测试理论基础和方法，给出了实际测量结果并该对方法存在的问题进行了讨论。简述了试验过程中发生蠕变的事实并给出最佳试验的砝码质量和试验国外还给出了特征长度，变形模量与冰密度和未冻液体含量的试验关系。     

辽东湾海冰漂移的动力要素分析

利用辽东海JZ20－2海域冰期气象、水文和海冰的实测资料和海冰数值模拟结果，对海冰漂移过程中风和流的拖曳力、海冰内力、科氏力和海面倾斜力要素的基本特征进行了分析；采用海冰热力－动力模式对1999年2月3日6：50至2月5日6：50间辽东湾海冰进行了48h数值模拟，对并JZ20-2海域的海冰动力要素进行了对比分析。发现海冰内力、风和流的拖曳力为同一量级，海面倾斜力和科氏力明显较小，其均值的比例关系依次为14．7：18．8：32．6：1．5：1．0；海冰各动力要素相互影响，共同决定了海冰的漂移速度和运动轨迹。     

2001—2018年基于MODIS遥感影像的青海湖湖冰物候变化特征分析及其影响因素

青海湖是青藏高原上最大的咸水湖,研究该区域冬季湖泊冻融时间的变化趋势及其与气候变化之间的关系,可以为预测未来气候对青海湖水情变化提供重要的见解。根据冰的亮度温度值高于水的亮度温度值这一差异,使用2001—2018年MODIS MOD02QKM数据产品和Landsat TM/ETM+遥感影像分别提取了青海湖开始冻结、完成冻结、开始消融和完成消融四个时间点的数据,综合分析青海湖湖冰物候特征变化,并结合气象数据,得出湖冰物候变化对气候的响应。结果表明：青海湖每年11月左右进入冰期,12月开始形成稳定的冰盖,次年3月或4月开始消融。湖冰覆盖时长和封冻期的变化趋势基本相同,整体上呈现出缩短的趋势,湖冰消融期整体上呈现出先缩短后增加的趋势;2001—2018年,平均首日冻结面积为8.15%,平均冻结速率为192.02 km²?d^?1,开始冻结和完成冻结的日期略有延迟,开始消融和完成消融的日期已经大大提前;冬季温度越高,青海湖湖冰封冻时间越短,日照时数越长湖冰覆盖时长越短,对于湖冰消融期来说,降水量越多湖冰消融速度越慢,平均风速越大湖冰消融速度越快。初步认为,气温是湖冰冻融的主要因素,预测未来1—2 a青海湖冬季气温仍会呈现上升趋势,湖冰封冻时长也会出现缩短趋势。     

基于颗粒流数值方法的岩石压剪破坏细观特征研究

压剪破坏是影响岩体工程安全的主要因素,基于颗粒流程序的伺服控制原理,采用等效晶质模型模拟了粉砂质板岩的压剪破坏过程,通过与室内试验对比验证了其适用性,并从细观角度揭示了岩石在压剪过程中的破坏机理。结果表明:裂纹增长速率与试件压剪过程中经历的弹性、塑性和破坏3个阶段具有相关性;张拉、剪切裂纹呈同步增长趋势,但峰后张拉裂纹增长速率快于剪切裂纹,即试件峰后以张拉破坏为主;随剪切角增大,由沿晶和穿晶断裂向以沿晶断裂为主转变,裂纹数量减小且扩展方向向断裂面集中;穿晶断裂的扩展更容易导致局部失稳,即在宏观上表现为塑性阶段;穿晶裂纹主要沿断裂面扩展、贯通,一定程度上可以抑制断裂面附近较大破裂块体的产生。     

深井冰冷冻系统

深井降温是深部矿产资源开采过程中的主要技术问题之一 ,讨论一种深井降温的新技术及方法冰冷冻系统     

喀斯特洞穴晶体生长速率的古气候重建意义

为了从石笋中提取更多的古气候信息,以用于气候预测,需要研究现代洞穴沉积过程与周围环境变化的关系。本文通过对贵州5个洞穴现代沉积玻片上菱形方解石的长度与滴水变率观测研究发现,在洞穴滴水不间断的情况下,滴水变率较小的滴水点,菱形方解石晶体长轴生长速率较快,反之,生长速率较慢。反映在石笋中,石笋晶体粒径较大说明处于降水稳定时期,石笋晶体粒径较小指示沉积时期降水变率较大,气候不稳定。     

SNOW AND ICE ALBEDO MEASURED WITH TWO TYPES OF PYRANOMETERS1

ABSTRACT: In order to obtain total short-wave albedos of snow and ice, both incident and reflected solar radiation were measured over a frozen lake surface using two different types of radiation measurement devices: a Kipp and Zonen thermopile pyranometer with a spectral sensitivity of 300 to 2800 nm and a LI-COR photovoltaic pyranometer with a spectral sensitivity of 400 to 1100 am. The spectral response of the LI-COR pyranometers limits its use as a short-wave radiation measurement device. Therefore, two equations were developed to adjust both the daily incident radiation data and the daily reflected radiation data measured by the LI-COR instrument to total short-wave radiation values, i.e., to the waveband of 300 to 2800 nm (visible to near-infrared spectrum). The LI-COR data were then adjusted, and a total short-wave adjusted albedo was calculated with a modeling efficiency of 0.97.     

EFFECT OF SIMULATED CLIMATE CHANGE ON SNOWMELT RUNOFF MODELING IN SELECTED BASINS1

ABSTRACT: The projected increase in the concentration of CO₂ and other greenhouse gases in the atmosphere is likely to result in a global temperature increase. This paper reports on the probable effects of a temperature increase and changes in transpiration on basin discharge in two different mountain snowmelt regions of the western United States. The hydrological effects of the climate changes are modeled with a relatively simple conceptual, semi-distributed snowmelt runoff model. Based on the model results, it may be concluded that increased air temperatures will result in a shift of snowmelt runoff to earlier in the snowmelt season. Furthermore, it is shown that it is very important to include the expected change in climate-related basin conditions resulting from the modeled temperature increase in the runoff simulation. The effect of adapting the model parameters to reflect the changed basin conditions resulted in a further shift of streamflow to April and an even more significant decrease of snowmelt runoff in June and July. If the air temperatures increase by approximately 5°C and precipitation and accumulated snow amounts remain about the same, runoff in April and May, averaged for the two basins, is expected to increase by 185 percent and 26 percent, respectively. The runoff in June and July will decrease by about 60 percent each month. Overall, the total seasonal runoff decreases by about 6 percent. If increased CO₂ concentrations further change basin conditions by reducing transpiration by the maximum amounts reported in the literature, then, combined with the 5°C temperature increase, the April, May, June, and July changes would average +230 percent, +40 percent, ?55 percent, and ?45 percent, respectively. The total seasonal runoff change would be +11 percent.