广西北回归线两侧环境优势与可持续发展

北回归线,有人简称为“太阳转身的地方”！由于地球环绕太阳公转,太阳的光线直射点每年都在南纬23°26'与北纬23°26'之间往复移动,人们就把南纬23°26'和北纬23°26'称为南、北回归线。1976年第16届国际天文学联合会上决定将2000年的回归线位置定为23°26'21"448N。北回归线经过16个国家和地区,其中大部分地区是沙漠、草原和海洋,只有经过我国的四个省区（台湾、广东、广西、云南）,四季葱绿、鸟语花香、生机盎然,誉为北回归线沙漠带上的“绿洲”。广西地处祖国的南疆,位于东经104°29'—112°04',北纬20°54'—26°23',北回归…     

陕西省的生态环境问题与治理对策

1陕西省情概述陕西省简称陕或秦,位于中国大陆的中部。北邻内蒙古自治区;东隔黄河与山西省相望;东南与河南省、湖北省接壤;南连重庆市、四川省;西接甘肃省与宁夏回族自治区。在东经105°29'～110°15'与北纬31°42'～39°35'之间。南北较长,东西较窄。南北跨纬度7°53',长约870km;东西跨经度5°46',宽约510km,最窄处宽约200km。面积20.58×104km2,约占全国总面积的2.1%。陕西省地处内陆腹地,具有重要的区位优势。它是欧亚大陆桥上连接中国东西南北的枢纽;在西部大开发中,陕西作为大西北的门户,具有承东启西南连北接的重要功能。是我国东西南…     

四川若尔盖黑颈鹤保护区生态环境特点及水化学特征

若尔盖黑颈鹤自然保护区,是以保护珍稀动物黑颈鹤及高寒沼泽生态环境为重点的保护区,它位于四川省若尔盖县中部,北纬33°26′～56′,东经102°30′～103°00′,面积约553.4km~2。1985年9、10月,我们考察了保护区,现就生态环境特点及水化学特征两个问题,简述于后。     

下扬子地区中生界古地磁及其构造解析

对在东经115°30′～119°15′、北纬29°30′～34°范围内的下扬子地区中生界,笔者分设10个采点采集定向标本58块。岩样经系统退磁和各种常规检验,并同步进行了磁组构解析、筛选出原生剩磁,从而较系统地获得了该区内T_3-K_2各层系有代表性的古地磁资料。经与华北、华南中生代以来古地磁资料对比后发现:下扬子层体从三叠纪开始于赤道附近与华南地块分离,在晚侏罗—早白垩世快速向北运动,至中纬度带与华北地块拼贴而包容于白垩纪以来的华北块体,晚白垩世随华北块体转变为指向北西西方位的运动,到早第三纪晚期开始又转变为指向南南东方位朝低纬度快速运动,直至晚第三纪晚期才与中生代以来一直在中低纬度带上徘徊的华南地块拼合,从而构成了统一的中国东部大陆块体。     

烟台市污水深海排放工程

烟台市是我国沿海１４个进一步对外开放城市之一，它位于东经１１９°３４'～１２１°５７'，北纬３６°１６'～３８°２３'之间，三面环海，是我国著名的滨海风景旅游城市之一。附近海域分成两个海湾，东为芝罘湾，西为套子湾。近年来，由于烟台市区工业的发展和人口的增长，使得城市污水量大为增加，对城市环境造成污染并危害近海海域的生态环境，急需进行处理。沿海城市利用海洋处理城市污水是一种合理利用海洋水体的环境容量和自净能力，同时又使环境质量得到保证的可行方法。国内外对沿海城市污水深海排放已经做了大量工作。烟台市污水…     

长江口九段沙湿地原生植被的保护及开发利用

研究了长江口九段沙湿地的原生植被,结果表明,九段沙湿地植被多行无性繁殖;植物种群数量少,同一种群中多同生群植物;植物群落结构简单、群落演替的原生特征明显;植被的相对密度大、生物量高,植物中多属可开发利用的资源植物,具有开发利用的潜在特性;九段沙原生植被在上海市、江苏省的部分地域的空气质量改善过程中起着重要作用;其湿地植被一旦得以生态型开发利用,有利于营造一个鸟类栖息、觅食的乐园,可减缓浦东国际机场迁徙鸟类活动的压力。提出了保护和开发利用九段沙原生植被必须遵循的原则。     

湖北省林业土地资源的保护与利用

一、前言湖北省地处长江中游,位于东径103°30′～116°10′,北纬29°05′～33°20′之间,全省土地总面积18.95万KM~2,林业用地占总土地面积的43.61%,森林覆盖率为25.7%,(1989年林业厅统计)分布不匀,27个山区县的复盖率(X±8)为33.O±10.36%,丘陵县28个,复盖率为23.13±9.31%,18个平原县的森林覆盖率为3.22±2.69%,覆盖率达标的仅16个县,占全省73个县(林区)的21.92%,山区(山,丘陵)占总土     

利用线性构造密度分析获取尼日利亚构造控矿的证据——陆地卫星研究

在所有30幅陆地卫星图象(覆盖了北纬8°以北尼日利亚整个地区)上,凡长度在5km以上的线性构造都进行了解译。每幅1:1000000的图象,都使用了4、5、6和7光谱波段。利用这些图幅作成的解译镶嵌图,绘制了一幅尼日利亚线性构造图。根据线性构造组合的空间和方向分布特征进行的区域线性构造分析,揭示出NE—SW、NW—SE和N—S三组总构造走向。对每个1°×1°网格内的线性构造密度都用常规方法进行了测定,并据此结果绘制了线性构造密度等值线图。线性构造密度图与原生矿产图的对比表明,高线性构造密度区与已报道的诸如Fe、Sn、Au、Pb—Zn和U等大多数原生矿具有良好的相关关系;这种相关关系说明尼日利亚的原生矿化作用受构造控制。因此,该线性构造密度图已成为一种有助于尼日利亚固体矿产勘探的有用的基本图件。     

新疆哈密香山基性-超基性杂岩体的岩石学和地球化学

<正> 香山基性-超基性杂岩体位于新疆哈密境内,地理坐标为东经94°30′—94°37′,北纬42°15′—42°20′。本文研究了该杂岩体的岩石学、地球化学、矿物学特征,提出了香山杂岩体成因假说。     

杭州湾北岸上海石化总厂附近海域浮游动物生态的初步研究

1989年11月对杭州湾北岸上海石化总厂附近(121°10′-121°26′E、30°30′-30°48′N)调查区进行了大型浮游生物调查。结果表明,调查区范围内浮游动物平均总生物量为187.3mg/m3,与历史同期资料相比明显增高。浮游动物经鉴定有13种,分半咸水性河口种类和低盐沿岸种类。群落结构指数分析表明,站位丰富度(d)低(0.56-1.37),单纯度(Σπ2)高,多样性指数(H′)低(1.25—2.17)。优势种突出,优势度高,优势种聚集强度指标值高,种类间个体分布不均匀,且主要集中在金山嘴附近及总厂附近沿岸。本调查区浮游动物群落结构已受到轻度污染影响。本文还对保护杭州湾渔业水域措施提出建议。     

杭州校园中不同植被对PM2.5的吸附能力

为合理安排绿地配置,极大发挥植物改善生态环境的功能,为城市系统绿化的功能化规范化经济化提供更加合理的理论支持,通过获取杭州电子科技大学校园内现有的4种植被的不同时间段和不同离地高度的ρ（PM_2.5）,用统计学的t检验方法研究了ρ（PM_2.5）的变化规律.以一天当中不同时间空地的ρ（PM_2.5）作为参照,分别对相同时间、不同植被区域、不同高度和不同时间、相同植被区域、相同高度的ρ（PM_2.5）作对比.结果表明:①早晨水杉林、松树林、混合林的PM_2.5吸附能力相似,与空地的平均差值分别为14.36、12.00和12.79 μg/m3;草地的PM_2.5吸附能力较差,与空地的平均差值仅为4.75 μg/m3.中午时,水杉林的PM_2.5吸附能力最强,与空地ρ（PM_2.5）平均差值为10.87 μg/m3,其次为混合林（8.18 μg/m3）,草地ρ（PM_2.5）反而比空地高14.90 μg/m3.下午水杉林与混合林的PM_2.5吸附能力与中午相比略微减弱.晚上,除混合林外,其他3种绿地均与空地无显著差异.②对比距地面0.1与1.5 m高的空气中ρ（PM_2.5）的差异发现,一般情况下树林中0.1 m处ρ（PM_2.5）大于1.5 m处,空地0.1 m处ρ（PM_2.5）小于1.5 m处.研究显示,大部分植被在早晨吸附能力最强、晚上最弱,不同植被对于PM_2.5的吸附能力也有所不同.由此,在所统计的植被中,水杉林对空气中PM_2.5的吸附能力最强,在以后的绿地规划中,可考虑多增加水杉林的种植面积;但在增加城市林地面积减少空气中PM_2.5的同时,还应考虑到植物自身生理能否带来一些城市负面影响,从面得出最优种植方案.      

滇池湖滨带湿生乔木湿地构建技术研究

采用以草本植物为主构建的湖滨湿地存在的主要问题是挺水植物繁殖速度快,生物量大,如每年不及时对死亡植株进行收割,会加快湖泊淤积速度,对湖泊水体造成二次污染;大面积湿地挺水植物的管护和收割,势必造成湿地管理强度和费用大幅提高。针对上述问题,文章重点介绍了在滇池草海湖滨带中以湿生乔木植物代替草本挺水植物的湖滨湿地构建技术现场试验研究成果,在湖滨带基底修复的基础上,选择垂柳、滇杨、中山杉、水杉、池杉和竹子等湿生植物开展现场试验,研究结果推荐适应能力较强、成活率较高和景观效果好的垂柳、中山杉为滇池湖滨带湿生乔木湿地构建的主要树种,为受损湖泊湖滨带生态修复提供借鉴。     

Resistance of the grain mite Acarus siro L. (Acarina,Acaridae) to unfavourable physical conditions beyond the limits of its development

The resistance of the grain mite Acarus siro to unfavourable physical conditions was studied to determine how long some members of a population might survive so that development and increase could continue if conditions became favourable. Preliminary experiments showed that: (i) the eggs formed the most resistant stage, both to extreme temperatures and to desiccation; (ii) the most resistant eggs were those in an early stage of development, and that resistance declined with age; and (iii) environmental conditions prior to oviposition influenced resistance, resistance being greater in eggs from populations reared at near threshold conditions than in those reared at ecologically more favourable temperatures and humidities.Experiments with eggs exposed to lethal high and low temperatures and to both favourable and desiccating humidities show that above 30°C and below 0°C, relative humidity ceased to affect survival, the eggs being killed by heat or cold before the effects of desiccation became important. Eggs were fairly susceptible to high temperatures; none survived longer than 10 h at 35°C or 35 min at 40°C. They showed greater tolerance to low temperatures, surviving up to a maximum of 12–14 days at ?10°C and 24–26 days at ?5°C. At 0°C, the maximum survival period varied from 80 days at 20% RH to 180 days at 90% RH. For eggs exposed at temperatures within the developmental temperature range to relative humidities from 20 to 50%, survival appeared to be directly related to humidity and inversely to temperature, maximum survival periods ranging from 20 days (20% RH) to 45 days (50% RH) at 5°C, and from 1 day (20% RH) to 3 days (50% RH) at 30°C.     

Effects of road age on the structure of roadside vegetation in south-eastern Australia

In many agricultural landscapes, roadside (or road verge) environments provide important refuge for threatened native species and ecosystems, and are often selected as benchmark sites to guide restoration activities. However few studies have investigated potential temporal variability in roadside vegetation conditions. In this paper we used archived cadastral maps to determine road age and examine potential variability in roadside vegetation structures in a typical rural landscape in south-eastern Australia. We found significant differences in the density of mature trees for road segments in different road-age categories. The oldest roads (<1870s) were characterized by having the greatest density of large hollow-bearing Eucalyptus trees, but few native conifer trees or shrubs. Roads surveyed when broad-scale clearing commenced (1870–1879), and not the oldest roads, were found to be more intact in terms of the density of large pre-settlement trees, range of tree stem-size classes and overall shrub diversity. By contrast, the youngest roads (post-1900s) had the greatest number of native conifer trees, but few shrubs or large Eucalyptus trees. As a result, roads of different ages had different densities of hollow-bearing trees, which is discussed in terms of past land-use legacies. These results have important implications for selecting roadsides as benchmark sites for restoration activities, and highlight the critical importance of roadsides to conserving native biota in agricultural landscapes.     

Telomeric attrition with age and temperature in Eastern mosquitofish (Gambusia holbrooki)

Telomeric attrition has repeatedly been found to correlate with the ageing of organisms; however, recent research is increasingly showing that the determinants of attrition dynamics are not well understood. This study examined the relative telomere lengths in Eastern mosquitofish, Gambusia holbrooki, kept at different temperatures and at different ages. Newly born fry were randomly selected for one of four treatment groups: 20, 30, 20–30, and 30–20 °C, where the third and fourth treatment groups were gradually changed from their starting temperature to their final temperature between days 10 and 14. Telomere length was measured, and it was found that length decreased with age and that fish exposed to the 20 °C treatment had significantly shorter telomeres than those that received the 30–20 °C treatment. Telomeric attrition with age agrees with results previously found in studies of telomeres; however, the variation in attrition with temperature was not simply predictable and may be the synergistic effects of temperature and some other factor.     

瓦里关山大气CH4本底变化

利用 1991 0 5— 2 0 0 2 0 5期间实测资料 ,分析了瓦里关全球基准站 (36°17′N ,10 0°5 4′E ,海拔 3816m)大气CH4本底特征 ,并探讨了与源汇过程的关系 .结果表明 ,瓦里关山大气CH4体积分数本底范围和增长趋势与 6 0°N— 30°N平均水平大致相符 ,但本底体积分数季节变化与所处纬度带基本特征和季节振幅的地理分布差异较大 ,年增长值波动也与全球平均状况并不完全一致 ,是所在地区多种CH4源汇和大气输送共同作用的结果 .瓦里关站提供的大气CH4本底观测资料 ,既能体现亚洲内陆地域特点又具有全球代表性 ,辅以其它相关资料 ,还可进一步揭示中国内陆高原大气CH4本底特征的成因     

The effect of thermal instability of intact human chorionic gonadotropin (ihcg) on the application of its free β-subunit (free βhcg) as a serum marker in down syndrome screening

The kinetics of free βhCG concentrations were measured in 30 maternal whole blood samples from second-trimester pregnancies during 72 h incubation at 3, 20, and 30°C. Dissociation of intact hCG (ihCG) was undetectable at 3°C and produced a more than 20 per cent increase of free βhCG at 20°C and a more than 100 per cent increase at 30°C. hCG dissociation at 30°C was not reduced by a protease inhibitor (sodium iodoacetate) and also occurred in purified hCG dissolved in a protease-free incubation medium. These results were reproduced under conditions of sample transport by post at different environmental temperatures. In conclusion, reliable free βhCG assessment requires that the specimen be kept cool from vene puncture until assay or completely other transport strategies have to be considered. Evaluation of free βhCG as an effective marker in prenatal Down syndrome screening must be reconsidered from this aspect.     

Survival of Porcine Reproductive and Respiratory Syndrome Virus in Pork Products

There is a risk of virus transmission through contaminated pork, and many viruses are considered potential hazards for both humans and livestock. The risk of transmission may be elevated with importation/exportation of meat between countries globally. Survival of porcine reproductive and respiratory syndrome virus (PRRSV) in different pork products has not been studied. The present study evaluated PRRSV survival in four different products: fresh sausage, ham, bacon, and acidified sausage prepared with experimentally contaminated pork. These products were prepared according to standard methods used by the manufacturers of pork products, and then stored at room temperature, 4 °C and ?20 °C. PRRSV was detected only in fresh sausage for up to 15 days at 4 °C and for 30 days at ?20 °C. No PRRSV was detected at any temperature in any of the other three products. These preliminary data provide valuable information for the pork processing industry, as well as in planning for import/export of these products among different countries.     

偏转角影响磁纤维捕集Fe基细颗粒的数值模拟

为了研究磁性纤维对钢铁行业细颗粒物的控制效果,基于计算流体力学-离散相模型（CFD-DPM）对高梯度磁场中含尘气流方向与背景磁场方向夹角（偏转角）分别为0°、15°、30°、45°、60°、75°、90°时磁性单纤维捕集Fe基细颗粒进行数值模拟.分别研究高梯度磁场作用下颗粒粒径、入口风速、磁场强度对颗粒运动轨迹和捕集效率的影响.结果表明：高梯度磁场中偏转角影响磁性纤维捕集区域的位置,当角度为0°时,在纤维正对含尘气流方向区域形成颗粒捕集区,背风侧形成较大空腔;当角度为90°时,在沿气流方向纤维两侧形成面积相等的捕集区域.偏转角对小颗粒捕集效率的影响较小,当角度为0°时,对于0.5μm的颗粒捕集效率为4.1%,当角度为90°时捕集效率为3.9%.随着粒径的增大,捕集效率的增长速率先减小后增大,对于不同粒径的颗粒,当角度为0°时捕集效率最高.当风速在0.02~0.04m/s范围时,随着角度从0°增加到90°,捕集效率先降低,在45°附近达到最小值,然后升高.磁场强度的增加有利于提高捕集效率,但不同角度时的增长速率有所不同.当偏转角为0°和60°时,背景磁场强度为0.1~0.3T范围时增长速率明显大于0.3~0.9T范围内,而当偏转角为30°和90°时,背景磁场强度为0.1~0.5T范围时增长速率高于0.5~0.9T时的增长速率.     

爆炸物污染土壤中2，4-DNT和2，6-DNT的生物降解中试研究

设计采用包括土壤生物降解、反硝化以及循环混合系统构成的中试流程,模拟原位生物修复工艺,依靠污染土壤自身的生物降解过程去除2,4-二硝基甲苯(2,4-DNT) 和2,6-二硝基甲苯(2,6-DNT).结果表明,即使在温度较低的条件下（8～15℃）,2,4-DNT 和2,6-DNT仍可以被完全去除.两者虽然属于同分异构体,但前者的生物降解速率大大高于后者.系统可以维持自身的碱度平衡和保证无机营养供应,无需调节或补充;反硝化能够正常进行,从而防止亚硝酸根在系统内积累抑制DNT生物降解,但要彻底去除亚硝酸根及硝酸根,需要外加碳源.