Tritium Distribution in Ground Water around Large Underground Fusion Explosions

Tritium will be released in significant amounts from large underground nuclear fusion explosions in the Plowshare Program. The tritium could become highly concentrated in nearby ground waters, and could be of equal or more importance as a possible contaminant than other long-lived fission-product and induced radionuclides. Behavior of tritiated water in particular hydrologic and geologic environments, as illustrated by hypothetical explosions in dolomite and tuff, must be carefully evaluated to predict under what conditions high groundwater concentrations of tritium might occur.     

Tritium and carbon-14 distributions in seawater from under the ross ice shelf project ice hole

The tritium and carbon-14 activities of seawater samples collected from 22 to 200 meters below the ice at the Ross Ice Shelf Project ice hole are reported. The tritium results show that the waters below the ice have exchanged with Ross Sea water since the advent of nuclear testing. The carbon-14 results indicate that waters in the upper layer exchange in time periods of less than 6 years. Measurements of these isotopes in seawater under the Ross Ice Shelf in McMurdo Sound show that this water has a different history.     

昆虫病原线虫防治稻水象甲幼虫的研究

在室内测定了昆虫病原线虫(S.feltiaeOtio)对检疫性害虫——稻水象甲幼虫的致死中量(LC50,LC90)和致死中时间(LT50,LT90),旨在为大规模应用昆虫病原线虫防治稻水象甲提供理论依据。将TDM模型引入试验结果的分析中,得出了昆虫病原线虫防治稻水象甲幼虫的TDM模型以及LC50、LC90与LT50、LT90。S.feltiaeOtio对于稻水象甲幼虫剂量效应β值为1.22,在接种后第3～12d,S.feltiaeOtio不同时间段的LC50分别为115.57×106、30.48×106、12.60×106、7.27×106、3.14×106IJ/m2;不同时间段的LC90分别为1123.03×106、296.23×106、122.48×106、70.69×106、30.52×106IJ/m2。在0.1×106～0.8×106IJ/m2的浓度范围内,LT50的估计值范围为3.41～1.26d;同样,模型还给出3个高浓度处理的LT90值,即在0.4×106～1.6×106IJ/m2的浓度范围内,LT50的估计值范围为4.73～2.75d。     

Tritium enrichment by gas-solid chromatography: technic for low-level analysis

A palladium chromatograph was developed that can detect less than 10 atoms of tritium per 10(18) atoms of hydrogen. Columns operated at ambient temperature have 70-liter hydrogen capacity (50-milliliter water sample) and give 60 percent recovery in the first 500 cubic centimeters of gas evolved.     

Improvement of a dual-sensor horizontal penetrometer by incorporating an EC sensor

Following the development of a dual-sensor horizontal penetrometer for the simultaneous measurements of soil water content and strength, an electrical conductivity (EC) sensor with a 4-ring Wenner-array was incorporated into the cone of the horizontal penetrometer. In order to overcome the cross-modulation of signals from water content and EC sensors, two filters with specific pass-bands were connected in each circuitry. Both laboratory calibration and field test were conducted, and the experimental results showed that the improved technique could provide more informative data to interpret soil physical conditions at field-scale.     

Water vapor: stratospheric injection by thunderstorms

Infrared radiometric inference measurements of the mass of water vapor injected into the lower stratosphere and upper troposphere by a number of plains thunderstorms show an average threefold increase over the fair weather background mass of water vapor. These airborne measurements, made from the National Aeronautics and Space Admninistration Convair 990 jet laboratory, extended over a sample size much larger than that possible by balloon and other techniques.     

参藻混养生态系统中孔石莼、蛋白核小球藻与刺参的相互作用研究

为了探讨参藻混养生态系统中孔石莼Ulva pertusar、蛋白核小球藻Chlorella pyrenoidosa与刺参Apostichopus japonicus的相互作用,采用实验生态学方法进行了10~6、10~5 cells/mL两种浓度的蛋白核小球藻与孔石莼及刺参不换水混养的生态效应研究。结果表明:孔石莼和小球藻能有效地吸收养殖水体中的氮磷;10~6cells/mL浓度的小球藻在与孔石莼、刺参混养时对孔石莼有明显的抑制作用,而10~5 cells/mL浓度的小球藻对孔石莼有一定的抑制作用。研究表明,小球藻浓度为10~5 cells/mL的混养组在水质、刺参生长方面与孔石莼混养组相近,且能较好地抑制孔石莼过快生长。     

麦积山景区生态需水特征(英文)

[目的]研究麦积山景区生态需水特征。[方法]运用麦积山景区内多年土壤湿度资料及气象资料,对景区内生态需水特征进行分析。[结果]麦积山景区内年实际需水量为678×106m3,土壤含水占21%,蒸散量占79%;最小生态需水定额为480×106m3,土壤含水占16%,蒸散量占84%;最小适宜生态需水定额为624×106m3,土壤含水占18%,蒸散量占82%。降水量为614×106m3,可消耗水中水分盈余78×106m3。降水量大于蒸散量的年份占76%。自21世纪80年代以来,蒸散量呈线性增加趋势,一年之中,6~10月降水量大于蒸散量,11~12月以及1~5月降水量小于蒸散量,蒸散需水靠土壤水调节。春季降水量与蒸散量相差较大,对瀑布、溪流等自然有一定影响。[结论]该研究结果为麦积山景区水资源的合理利用及长远规划提供了依据。     

枫杨种源苗期生长性状地理变异及遗传参数估算

用枫杨全分布区内收集的53个种源在安徽铜陵进行苗期试验。枫杨种子千粒重及室内发芽率均存在明显的地理种源差异。参试种源苗期生长差异十分明显,最优种源比最劣种源的苗高、地径和生物量分别高出184%、127%和74%。枫杨苗期生长与生物量性状间的表型及遗传相关密切,种子千粒重与发芽率的广义遗传力为0.97～0.99,受强度遗传控制,生物量及生长性状的广义遗传力为0.57～0.72,受中等强度遗传控制。种子千粒重主要表现为东西经向变异,而苗期地径生长与总生物量则表现明显的南北纬向变异趋势,因此,分布区东部种源的种子一般较重,而分布区南部种源的地径生长及总生物量一般优于北部分布区的种源。枫杨的生长变异还受到水系、气候区等因素的强烈影响,它在长江流域、漓江—湘江—洞庭湖水系、西部地区、沿海地区、长江以南及长江以北地区等表现出不同的变异模式。根据苗高、地径及总生物量等主要性状,构建综合选择指数函数I=0.2891X1（总干重）+0.0058X2(苗高)-0.03136X3(地径),并评选出江西南部的吉安、陕西中部的汉中、江西西北部的武宁、四川东部的达县和湖南洞庭湖的益阳等5个种源为苗期生长优良种源。     

枫杨种源苗期生长状地理变异及遗传参数估算

用枫杨全分布区内收集的53个种源在安徽铜陵进行苗期试验。枫杨种子千粒重及室内发芽率均存在明显的地理种源差异。参试种源苗期生长差异十分明显,最优种源比最劣种源的苗高、地径和生物量分别高出184％、127％和74％。枫杨苗期生长与生物量性状间的表型及遗传相关密切,种子千粒重与发芽率的广义遗传力为0．97－0．99,受强度遗传控制,生物量及生长性状的广义遗传力为0．57－0．72,受中等强度遗传控制。种了千粒重主要表现为东西经向变异,而苗期地径生长与总生物量则表现明显的南北纬向变异趋势,因此,分布区东种源的种子一般较重,而分布区南部种源的地径生长及总生物量一般优于北部分布区的种源。枫杨的生长变异还受到水系、气候区等因素的强烈影响,它在长江流域、漓江－湘江－洞庭湖水系、西部地区、沿海地区、长江以南及长江以北地区等表现出不同的变异模式。根据苗高、地径及总生物量等主要性状,构建综合选择指数函数I＝0．2891X1（总干重）＋0．0058X2（苗高）－0．03136X3（地径）,并评选出江西南部的吉安、陕西中部的汉中、江西西北部的武宁、四川东部的达且以和湖南洞庭湖的益阳等5个种源为苗期生长优良种源。     

论三北地区冻结滞水的生态环境效益

本文依据野外观测和室内模拟实验初步资料分析 ,冻结滞水是冬季冻结作用在包气带内形成的季节性固态地下水 ,具有独特的形成机制和倒置富水性及独立的水盐动态特征 ,对生态环境具有双重效应。冻结滞水比冻结前水量一般增加 8%～ 2 5 % ,最高增加 39.5 1% ,是天然和人工植物越冬、春季繁衍的水分代谢均衡不可缺少的 ,甚至是唯一水资源 ,是保持生态平衡的主导因子。当水量达到过饱和状态时 ,易形成冻胀、热融、滑塌、沉陷、盐渍化、沼泽化等不良地质现象 ,造成生态环境恶化 ;在水量 <5 %时造成天然和人工植被衰亡 ,加速荒漠化。这一课题属于跨学部多学科交叉应用基础研究 ,将为可持续发展农林牧业工程、环境水文地质、工程地质、荒漠化防治等提供科学的理论依据和技术方法 ,开拓国际前沿研究领域。     

Ionizing energy as an aid in exchange tritium labeling

The tritium labeling of organic compounds by the Wilzbach technique-that is, by simple exposure of the compound to tritium gas-is greatly accelerated by the simultaneous exposure of the system to a silent electrical discharge. The incorporation of tritium into benzene was increased by a factor of about 10(4) without undue decomposition. Cobalt-60 gamma-rays were found to be far less useful for increasing the tritium incorporation.     

Biological damage from intranuclear tritium: DNA strand breaks and their repair

Isotopic decay in tritiated thymidine in the DNA of frozen (-196 degrees C) Chinese hamster cells causes breaks in DNA strands to accumulate at a rate of 2.1 breaks per decay. After DNA is thawed the tritium-induced breaks repair rapidly with a half-time of 15 minutes at 37 degrees C. In comparison to breakage by x-rays, the efficiency of DNA strand breakage by tritium is equivalent to 0.48 rad per decay. This dose per decay is close to that predicted by simple dosimetric considerations (0.38 rad per decay) for irradiation by the beta particles from tritium.     

氚水示踪法研究非充分灌溉条件下作物耐旱性

以￣３Ｈ＿２Ｏ为示踪剂，用同位素示踪法对非充分灌溉的７大类作物耐旱性进行了试验研究，经６３个品种的５００余个样品的￣３Ｈ＿２Ｏ测定结果表明：在土壤含水量为凋萎系数以下的极度干旱状况下，作物处于萎蔫失水耐受时间时，给作物灌溉￣３Ｈ＿２Ｏ且复水时间为１．５ｈ，作物吸氘水量随此时间增值大的，其耐旱性强。同时发现，吸￣３Ｈ＿２Ｏ的量─—作物抗萎蔫能力与作物耐旱性成正比。将￣３Ｈ＿２Ｏ法与耐旱性盆栽鉴定法比较结果表明，氘水示踪失水作物抗萎蔫恢复能力是一种判别作物耐旱性的有效方法。     

RTDrift: A real time model for estimating spray drift from ground applications

A spray drift model called RTDrift was developed to estimate drift caused by ground sprayer machines. The sprayer was equipped with sensors measuring operational parameters namely spray pressure, boom height and movements, and geolocalisation. Climatic parameters, including wind speed and direction, were measured using a 2-D ultrasonic anemometer mounted on the sprayer. The nozzles spray drop size spectra were characterised using Phase Doppler Interferometer measurements. At every successive boom position, a diffusion-advection Gaussian tilted plume model computed the spray drift deposits for each drop class taking into account evaporation. The contribution of a single nozzle was calculated by integration of the individual puffs with respect to time and summation of the contributions of individual drops classes. The overall drift generated by the sprayer machine was obtained adding the contributions of all the nozzles. Field trials were performed on a fallow field with water and on crops with pesticides in various wind conditions. The ground drift was measured at different drift distances using fluorometric methods. When comparing the results of the model with experimental measurements of deposits, the model produced realistic maps of drift deposits. Some further improvement is needed in the presence of large scale eddies. The model offers potential benefits for the farmer as a real time drift estimator embedded on a sprayer machine.     

拔节期灌水对冬小麦根重与产量的影响

用盆栽的方法,在土壤养分一致的条件下,测定了15个冬小麦品种拔节期灌水与不灌水(对照)的生物产量和籽粒产量。结果表明:冬小麦有效穗数、生物产量以及籽粒产量的形成与拔节期的水分状况有密切关系;地下部的根干重与地上部的生物产量、地上部的生物产量与籽粒产量呈显著正相关,其相关程度与拔节期灌水与否有关;地上部生物产量与千粒重虽也呈正相关,但相关性大小与拔节期的水分条件关系不密切。拔节期灌水处理与不灌水(对照)冬小麦的地上部生物产量、籽粒产量和千粒重的差值,与冬小麦自身的抗旱指数呈反相关。     

Erosion of galilean satellite surfaces by jovian magnetosphere particles

The Galilean satellites of Jupiter-Io (J1), Europa (J2), Ganymede (J3), and Callisto (J4)-are embedded in the intense ion and electron fluxes of the Jovian magnetosphere. The effect of these particles on the icy surfaces of the outer three satellites depends on the fluxes and the efficiency of the sputtering of water ice by such particles. Recent laboratory measurements provided data on the erosion of water ice by energetic particles and showed that it occurs much faster than would be expected from normal sputtering theory. The Voyager spacecraft encounters with Jupiter provided the first measurements of ion fluxes (energies greater, similar 30 kiloelectron volts) in the vicinity of the Galilean satellites. Using the laboratory sputtering data together with particle measurements from the Voyager 1 low-energy charged particle experiment, the effects of erosion on the surfaces of J2 to J4 are estimated. It is shown that the surface of Europa could be eroded by as much as 100 meters over an eon (10(9) years). Column densities of water vapor that could be produced around the three satellites from particle bombardment of their surfaces are also calculated, and the sources and losses of oxygen in the gravitationally bound gas produced by sputtering or sublimation are estimated.     

Social behavior in hatchling green iguanas: life at a reptile rookery

Hatchling green iguanas (Iguana iguana) emerge from the ground in small groups in a communal nesting area on a small Panamanian islet and engage in complex social interactions. Iguanas from different clutches often join together before and during departure from the nest site. They also usually move around the islet and migrate from it to the larger adjacent landmass in social groups. These and other observations indicate that the sophistication of saurian social organization and neonate behavior has been underestimated.     

缢蛏扰动及排氨作用对上覆水氮营养盐含量和通量的影响

底栖生物的扰动及排泄等生命活动会影响沉积物-水界面营养盐含量与迁移状况。采用室内模拟培养缢蛏的方法,在23℃、盐度22、pH=8的环境条件下,设置低、中、高密度3组以及对照组,进行为期25 d的室内模拟实验,每隔5天采集上覆水进行氮营养盐组分含量和通量的测定,探讨缢蛏扰动及其排氨作用对上覆水中氮营养盐的影响。结果表明,缢蛏扰动促进了上覆水中氨氮(NH₄⁺)、硝态氮(NO₃^-+NO₂^-)含量的增加,随着缢蛏投放密度的增加,NH₄⁺含量呈现明显的增大趋势,而NO₃^-+NO₂^-含量先增加后降低。NH₄⁺通量为-0.195~0.273 mmol/(m²·d),即沉积物中的氨氮向上覆水中释放,NO₃^-+NO₂^-通量为-0.554~0.038 mmol/(m²·d),表明沉积物从上覆水中吸收硝态氮。考虑到缢蛏代谢排氨的影响,用排氨数据校核氨氮含量,尽管NH₄⁺含量有小幅降低,但随时间的变化趋势不变。另外NH₄⁺通量在实验初期变化较大,从沉积物向上覆水释放转变为上覆水中NH₄⁺向沉积物迁移,随后趋于平稳,变化不明显。因此,缢蛏的扰动促进了沉积物与上覆水之间氮营养盐的交换,其中排氨作用在实验前期对通量的影响较大,随时间的推移排氨作用的影响逐渐降低。     

基因诊断中DNA序列的快速检测法

目的：探讨一种DNA测序方法在临床中的应用。方法：用纯化试剂盒对PCR产物进行纯化．然后用310自动测序仪测定DNA序列。结果：准确测定了一长度为106bp的DNA序列。结论：本方法不但有快速、简便和准确的特点，尤其还对短片段的DNA更显优势．很适合于临床基因诊断中的测序。