温度对共聚酯型聚氨酯与其低分子量共聚酯共混物透气行为的影响

在20～80℃范围内的一系列温度下研究了H_2、N_2、O_2和CO_2气体对共聚酯型聚氨酯/低分子量共聚酯共混物的渗透行为。发现共混物透气系数对温度的Arrhenius作图在CE熔点附近出现转折点,共混物中结晶相的熔点可以通过透气性测量测定,由于CE的低结晶性,温度对共混物的透气系数-组成曲线影响不大,但在CE熔点以下和在CE熔点以上,有着不同的气体渗透活化能及气体渗透活化能-组成曲线。

YBa_2Cu_3O_(7-Y)超导体激光熔凝处理的研究

利用CO_2激光对YBa_2Cu_3O_(7-Y)块材进行熔凝处理后,证明可逆反应式YBa_2Cu_3O_(7-Y)(?)Y_2Cu_2O_5+4BaCuO_2成立,在结构上消除了孔洞等缺陷,使晶粒细化均匀,有序化程度及致密度提高,有效地提高了材料的临界电流密度J_c,从而提出用CO_2激光制备高温超导体YBa_2Cu_3O_(7-y)超导体块材、带材及线材实用化的新工艺.

激光光声显微镜微弱信号的描述

激光光声显微镜是近几年发展起来的微区表面或次表面显微探测的新技术,在金属、非金属材料特性的研究中有广泛的应用。我们建立了以CO_2激光器为光源,采用锁相放大技术处理微弱信号的光声显微镜装置。以金属、石墨、催化剂等材料为研究对象,建立了几种新的探测模型,探讨了与信号处理有关的光声图象分辨率的选择问题。

气升式藻类光生物反应器的特性及应用研究

对自行研制开发的气升式藻类光生物反应器的特性和应用进行了研究。反应器的主体包括主筒、导流筒和通气管，有10升和100升两种容积；二氧化碳配气装置由气体配制、配气罐和气体过滤装置三部分组成。反应器与配气装置均已申报国家专利。通过冷模实验，比较通气管和导流筒设置对气升式反应器的气含率、上升时间、下降时间、循环时间和导流筒内流体雷诺数的影响；提供提高二氧化碳传递速率和通气效率的理论论据。以小球藻和海带雌配子体无性繁殖系为研究对象，对光衰减规律进行了初步研究，建立了数学模型。用小球藻为材料，对100升反应器进行了应用研究。结果表明这台反应器可长期连续稳定运转，占地面积小，具有较高的传质、光能传输和利用效率，小球藻密度达到6.09 * 10~7cell/ml时，光照尚未成为生长的限制因子。以占地面积计，小球藻25天平均产量达到293.94g/(m~2 · d)。在小球藻密度提高时，无机碳源供应成为限制因子，补充CO_2可明显提高生长速率。利用10升反应器，分别对海带雌、雄配子体无性繁殖系进行培养，每天短时间通入二氧化碳混合气体，使海带无性繁殖系的对数生长期延长，雌配子体无性繁殖系日产量达到35.3mgDCW/(L · d)。

海水二氧化碳含量变化对颗粒碳酸钙溶解影响的研究

由于人类活动等影响，致使近一个世纪以来大气中CO_2含量持续上升。海洋是大气CO_2含量变化的一个巨大缓冲器，进入大气的CO_2约有40%被海洋吸收，这部分CO_2将与水体中二氧化碳系统作用。随着大气CO_2含量的继续增加，可能会导致浅海水体中碳酸钙的不饱和，沉积物CaCO_3将发生溶解，因而对某些海洋生物生长产生影响。因此，联合国教科文组织于1980年提出，要求对浅海CaCO_3溶解的问题予以重视。可是，因难以寻得适合此项研究的海域，以及海水CO_2系统本身的复杂性，至今尚未有人进行这方面的系统研究。中国渤、黄海水深较浅，受黄河水影响，沉积物中CaCO_3含量高，大气CO_2含量变化在较短时间内即可作用到海底，是进行上述研究的理想场所。鉴于海水CO_2系统的复杂性，特以实验室模拟，结合部分现场样品，进行分析探讨。以实验室模拟实验，得出方解石在不同二氧化碳分压，不同温度，总压力为1atm条件下的溶解过程，并以浅海沉积物样品进行了对照实验。在浅海区域，碳酸钙处于过饱和，颗粒CaCO_3进入沉积后，由于有机碳分解，导致部分CaCO_3发生溶解，对此，进行了南黄海沉积物柱样CaCO_3含量的分析测定，并加以讨论。另外，对大气二氧化碳含量增加，导致浅海碳酸钙饱和度降低，以致于颗粒碳酸钙发生溶解的可能性进行了探讨。

海带配子体和幼孢子体无机碳素营养的比较研究

采用pH漂移技术并结合Az、DIDS、SITS等抑制剂，研究了海带生活史不同世代－幼孢子体和配子体利用外源无机碳的途径以及无机碳对其光合碳利用的影响。结果表明：幼孢子体对无机碳的利用能力远远高于配子体，两者在密闭培养体系中光合碳利用均不改变海水碱度，因些可以用pH的变化直接指示无机碳的变化。在天然海水中(pH 8.1-8.3)，海带幼孢子体外源无机碳的利用形式主要是HCO_3~-,HCO_3~-由膜外碳酸酐酶(CA)水解成CO_2后扩散进入细胞，这种形式占全部无机碳供应的75％，其余的来自于游离CO_2，没有发现HCO＿3~-直接转运机制的存在；而配子体不具有膜外碳酸酐酶，只以海水中游离CO_2为碳源。提高海水中无机碳的浓度均能增加海带幼孢子体对无机碳的利用速率：当无机碳的浓度达到3.5mmol/L时，幼孢子体对元机碳的利用速率达到最大值；配子体利用无机碳的速率也随着海水中游离CO_2浓度的升市而升高，当游离CO_2浓度到饱和时，雌雄配子体的光合碳利用速率分别比在天然海水中提高了2.9倍和2.5倍，说明天然海水中的无机碳不能满足其最大生长的需要。在天然海水pH变化范围内(pH 8.1-8.3), pH本身不影响配子体光合碳利用速率，当pH高于8.3时，配子体碳利用速率随pH的升高而降低。优化海带配子体培养条件时维持海水培养基低pH (pH 8.1-8.3)及高CO_2浓度是保证无机碳素充分供应的基本条件。

不同海拔麻花艽植物光合特性的比较

[目的]探讨不同海拔下麻花艽植物的光合特性.[方法]通过植物先合作用对光强、温度和CO_2的响应和酶活性的比较,研究了不同海拔麻花艽植物的光合性质.[结果]高海拔的海北麻花艽植物光合作用受到低温、强光、低气压的限制.低海拔的西宁麻花艽植物的净光合速率较高,但是高海拔的海北麻花艽植物的 超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)和抗坏血酸过氧化物酶(AP的活性和丙二醛(MDA)的含量高于西宁的麻花艽植物.[结论]低海拔的麻花艽植物光合潜力和温度适应范围广,引种栽培具有极大的优势,但是高温有可能造成光抑制,会降低光合生产力.高海拔的海北麻花艽植物光合色素的含量较低但具有较高的抗氧化酶的活性,保护了光合机构免遭破坏.

祁连山海北高寒湿地微气象季节变化特征

对青海海北高寒湿地2004年的微气象观测资料分析表明:海北高寒湿地地-气长短波辐射、地表反射率、能量通量各分量、动量通量、气温、地温、风速、 CO_2交换量等季节变化明显.因受湿地下垫面性质影响,地表反射率在1～2月明显大于其他季节,7～10月小,表现出冬季高夏季低的"U"型变化特征.地面长波有效辐射无明显季节变化.分析还表明,海北高寒湿地夏季及春、秋季均为明显的热源,而在寒冷的冬季出现一定的"冷源"效应.海北高寒湿地地-气间CO_2交换量季节变化明显,年内4月和10月分别存在两个CO_2释放高峰期,夏季的7～8月为一个强吸收期.

舍饲绵羊甲烷和二氧化碳的日排放动态

运用密闭呼吸代谢箱系统,对3只舍饲绵羊24h（有间断）甲烷（CH_4）和二氧化碳（CO_2）日排放特征进行了研究。供试3只甘肃细毛羊体况相近（平均体重为（25±5）kg）,其基础日粮为燕麦干草和玉米精料,粗精比为6∶4。结果表明：供试绵羊CH_4和CO_2的平均排放量分别为11g/d和147g/d,CH_4排放的峰值分别出现在17：00和22：00左右,达0.4217g/h和0.8082g/h,直到0：00降至最小为0.2993g/h;之后趋于平稳,次日8：00左右再次达到排放高峰,排放量为0.6587 g/h。而CO_2在各个测定时间段内差异不显著（p〉0.05）。因此,舍饲条件下绵羊CH_4和CO_2排放量动态（g/m in）变化不同步。由此,推算出舍饲绵羊（25±5）kg年排放CH_4和CO_2总量分别约为4.38 kg和53.66 kg。

青藏高原高寒草甸生态系统碳通量特征及其控制因子

青藏高原特殊的气候变化特征,在区域生态系统碳动态平衡起着重要作用。本文就青藏高原不同生态系统CO_2通量的时空变化及其影响因子和控制途径进行综述,以明确青藏高原植草地生态系统的碳源汇状况及时空变化特征,为全球变化的研究提供依据。

HPLC-APCI-MS法分析测定白刺籽油中游离脂肪酸

利用荧光衍生试剂1,2-苯并-3,4-二氢咔唑-9-乙基对甲苯磺酸酯(BDETS)作为脂肪酸柱前衍生化试剂,采用梯度洗脱在Eclipse XDB-C_8色谱柱上对游离脂肪酸(FFA)(油酸、亚油酸、软脂酸和硬脂酸)衍生物进行分离.利用柱后在线的串联质谱以大气压化学电离源(APCI)正离子模式实现了各组分的质谱定性.荧光检测的激发和发射波长分别为λ_(ex)=333 nm,λ_(em)=390 nm.脂肪酸的线性回归系数大于0.9990,检出限为3.38～6.59 nmol/L.建立的方法具有良好的重现性.利用此方法对超临界CO_2提取的唐古特白刺籽油中几种游离脂肪酸进行了分析.结果表明白刺籽油中含有大量的游离不饱和脂肪酸.

青藏高原3种主要植被类型的表观量子效率和最大光合速率的比较

以海北高寒草甸生态系统定位站的涡度相关系统连续观测的CO_2通量数据为基础,分析了青藏高原的高寒矮嵩草(Kobresia humilis)草甸、高寒金露梅(Potentilla fruticosa)灌丛草甸和高寒藏嵩草(Kobresia tibetica)沼泽化草甸等3种主要植被类型在2005年植物生长季(6-9月)的表观量子产额(a)、最大光合速率(Pmax)和呼吸速率(Reco)的变化特征.结果表明:3种植被类型白天的净生态系统CO_2交换量(NEE)和光量子通量密度(PPFD)存在明显的直角双曲线关系(P＜0.05),其a、Pmax和Reco呈现出相似的季节变化趋势,在生长季初期(6月)最小,在7月或8月份达到最大;高寒矮嵩草草甸的a、Pmax和Reco大于灌丛草甸和沼泽化草甸,而后两者差别不大.

中国北方风成堆积的风化作用与环境变迁—U-Th、~(10)Be及元素地球化学的研究

The surface of the Earth is continuously undergoing changes as a result of weathering-erosion, plate tectonics and volcanic processes. Continental weathering-erosion with its complex rock-water interactions is the central process of global biochemical cycling of elements, and affects the long-term ocean atmosphere budget of carbon dioxide both through the consumption of carbonic acid during silicate weathering and through changes in the weathering and burial rates of organic carbon. Rates of the weathering-erosion depend on a variety of factors, in particular rock properties and chemical composition, climate (especially rainfall), structure, and elevation. They are quite variable on a regional scale. Thus, environmental changes in a region could be indicated by the history of weathering-erosion in the region. Recent attention has focused on increased silicate weathering of tectonically uplifted areas in the India-Asia collision zone as a possible cause for falling atmospheric CO_2 levels in the Cenozoic era. The wind blown dust deposits in the Loess Plateau is derived from the arid and semiarid regions in northwestern China, in turn, where the deposits have been derived from the Qinghai-Xizang Plateau and the high mountains around. Therefore, geochemistry of the wind blown loess-paleosol and red clay sequences may provide insight both to paleoenvironmental changes on the Loess Plateau, and to the uplift and weathering-erosion histories of the Qinghai-Xizang Plateau. In this paper, uranium-thorium series nuclides and cosmogenic ~(10)Be have been employed as tracers of weathering intensities and histories of the dust sediments in the Loess Plateau. Major elements, such as Na, Al, Fe etc., are also used to estimate degree of chemical alteration of the dust sediments and to rebuild the history of weathering on the Loess Plateau. First of all, using a low-level HPGe γ-ray detector, we measured U and Th series nuclides in 170 loess and paleosol samples from five sites in the Loess Plateau, going back 2.6 Ma. The results show that ~(238)U activities are disequilibrium with its daughter nuclide ~(230)Th in young loess-paleosol sequence, indicating that weathering was happened both in dust deposition site and in dust source regions. Using concentrations of ~(238)U and ~(232)Th in the samples, we estimated the amounts of ~(238)U leached out of from paleosols due to weathering. Further, based on analyses of ~(230)Th in paleosols deposited in the past ca. 140 ka, we determined when the paleosols weathered in the source regions. We conclude that most of the weathering in the dust-source regions may have occurred during the interglacials before dust deposition.

东濮凹陷文－桥－白地区异常高压储层沉积成岩特征及成因初探

In Dongpu depression, there are obviously overpressure phenomena below 2000-3200m. Research to the relationship between sedimentation-diagenesis and overpressure of reservoirs is in great need. In this paper, after analyzing and simulating the overpressure in Wendong, Qiaokou and Baimiao regions, we draw a conclusion that the fast sedimentation since Low Tertiary is one of the most important mechanisms for the formation of overpressure in Dongpu Depression. The gypsum in northern part of Dongpu Depression is the good seal for the development of overpressure. On the base of detailed work to the distribution and magnitude of overpressure in Wen-qiao-Bai regions, we selected several wells that have different overpressure to find the sedimentary and diagenetic differences of these wells. We find that compaction is obviously inhibited in overpressured reservoirs, which results in the linear relation between physical properties of reservoirs and sedimentary parameters, such as sorting coefficient, the content of matrix, etc. Reservoirs with great magnitude of overpressure have undergone more extensive erosion than the ones with low magnitude of overpressure, which probably is the result of the great solubility of CO_2 under high pressure. The great burial depth, the high content of matrix and the extensively developed cement of carbonate are the most important factors that influence the physical properties of reservoirs in Dongpu depression. Overpressure plays a constructive role in the physical properties of reservoirs. the overpressured reservoirs of Es_3~3 subsection in Wendong region are probably the ones that have good physical properties. From homogenetic temperatures that obtained form the fluid inclusions in quartz overgrowth, we find that there were 4 episodes of fluid flows in Dongpu depression. In conjunction with the analysis of the burial history of overpressured reservoirs, we draw conclusions that the first, second and third episodes of fluid flows took place in the extensive rifting stage of Dongpu Depression, the burial depth when the first episode of fluid flow took place was about 1500m, the age was about 36 my; the burial depth of the second and third episodes of fluid flow was between 1800-3000m at that time, the age was between 35-28my. The fluid flows of the second, third, and fourth episodes were in close relation to the overpressure and maybe were the results of the episodic hydrofracturing of overpressured mudstones and shales. The episodic fluid flow of overpressured mudstones and shales probably facilitates the cementation of carbonate, which decreases the physical properties of overpressured reservoirs. The dolomites and ferrodolomites maybe the products of the episodic hydrofracturing of overpressured mudstones and shales.

黄土中主要温室气体组分特征

Scientists have paid much attention to the greenhouse effects and the greenhouse gases for the fact of global warming. There are many uncertainties in the prediction of future climatic change. One of the important reasons causing the uncertainties is insufficient researches of the sources and sinks of greenhouse gases, especially, there is a missing sink in the global carbon cycle. The recent researches proposal that there may be an important carbon sink in the middle-latitude terrestrial ecosystems (vegetation and soil) in the North Hemisphere, despite that there is much disputation about its position and amplitude. Chinese loess is located in the middle latitude area in the North Hemisphere, what kind of role does it play in and how does it influence on the balance of the global greenhouse gases budget? For this reason, many samples were taken and analyzed from wide range and multi-stratum of Chinese loess to understand characteristics of major greenhouse gases in loess and loess possible effect on global greenhouse gas budget. Using self-made spiral corer, we totally took 81 gas samples and 65 soil samples from 7 loess profiles in China such as Zhaitang loess section of Beijing, Pianguan, Xingxian, Lishi, Puxian, Jishan loess section of Shanxi Province, and Luochuan loess section of Shaanxi Province. The gas concentrations for CO_2, CH_4 and N_2O, the contents of N_2, O_2 and carbonate, and the carbon isotopic compositions of CO_2 and carbonate in loess strata sequences are observed and measured. In addition, 19 gas samples data of the Weinan loess section, Shaanxi Province are combination with this research to study characteristics of greenhouse gases in loess. This research indicates that (1) the free gases in loess are neither paleo-atmospheric gases nor modern atmospheric gases; (2) the concentrations of CO_2, CH_4 and N_2O in loess are higher than atmospheric level; (3) the δ~(13)C of loess CO_2 shows that the CO_2 in loess mainly comes from the oxygenolysis of organic matters, but because of isotopic exchange with carbonate in loess, the carbon isotopic exchange with carbonate in loess, the carbon isotopic compositions of loess CO_2 are much more heavier than organic original CO_2; (4) the concentration of CH_4 in Malan loess is lower because it is not favorable for the decomposition of anaerobic bacteria in the Malan Loess; (5) estimation of the total amount of the carbonate in loess reveals that loess is a huge carbon reservoir (about 850PgC). In addition, the impact of the deuterogenic carbonatization during the loess accumulation on the global carbon cycle was discussed, and the preliminary conclusion is that the research work is still not enough to evaluate the effect of loess on the sources and sinks of the anthropogenic CO_2.