129 resultados para ARM, 100 mT AF, 0.04 mT DF
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从纳米结构自组装和聚苯胺的刚性分子链出发,本文分别采用界面聚合法和直接混合反应法制备了一维聚苯胺纳米结构,探讨了产物结构及形成机理,并对其防腐蚀性能和机理进行了研究。主要研究结果如下: 1. 直接混合反应法是一种有效的制备聚苯胺纳米结构的方法,其产率高于界面聚合法。不同掺杂酸对产物结构和产率存在较大影响。 2. 在硫酸体系中,采用直接混合反应法合成了聚苯胺纳米纤维,其直径约为60-100 nm,长度达到几个微米,导电率为6.0 S/cm。综合考虑产物形貌、导电率和产率的最优合成条件为:硫酸浓度1 mol/L,苯胺与过硫酸铵配比0.8,反应时间16 h。 3. 在醋酸体系中,采用直接混合反应法可合成出纳米纤维和纳米管,反应物配比是产物形貌和产率的主要影响因素。在醋酸浓度为1 mol/L,苯胺浓度为0.2 mol/L,过硫酸铵浓度为0.1 mol/L,反应时间为24 h的条件下,可以制备得到螺旋状聚苯胺纳米纤维。 4. 电化学测试技术研究表明,直接混合反应法合成的聚苯胺纳米纤维具有比常规聚苯胺更好的防腐蚀性能;在3.5%NaCl溶液中,掺杂态聚苯胺产物的防腐蚀性能优于解掺杂态聚苯胺产物。聚苯胺在低碳钢表面钝化形成的氧化膜与纯聚苯胺涂层均具有一定防腐时效性,但防护时间较短。要获得更长期的防腐效果,需开发聚苯胺与常规涂层的混合体系。
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大部分贝类幼虫在发育过中要经历从浮游生活到底栖生活的变化过程,同时形态结构也要经历巨大的变化,这个过程称为变态。 变态是文蛤幼虫发育过程中非常重要的一个阶段。 药理学和细胞免疫学证据表明β肾上腺素样受体在文蛤幼虫变态过程中有重要作用。药理学实验分别采用了几种儿茶酚胺类受体的激动剂和抑制剂来处理幼虫,检验它们在幼虫变态过程中的作用。结果表明,在10μM和100μM的浓度下,肾上腺素(AD)和去甲肾上腺素(NA)中能够显著提高幼虫的变态率(p<0.05)。10μM和100μM浓度的AD能够提高幼虫变态率30%左右。10μM和100μM浓度的NA能分别提高幼虫变态率35.3%和27.6%。10μM的β受体激动剂-isoproterenol也能够显著的提高幼虫的变态率30%(p<0.05),但是α受体激动剂-phenylephrine在0.1μM到100μM的浓度范围内不能显著提高幼虫的变态率(p>0.05)。而且,1μM的β受体抑制剂-propanolol能显著的抑制AD或NA提高幼虫变态率的作用(p<0.05);但是α受体抑制剂-prazosin对AD或NA提高幼虫变态率没有显著性影响(p>0.05)。 此外本文还利用整装免疫细胞化学的方法进一步研究了文蛤幼虫不同发育阶段,神经系统和β肾上腺素样受体的发育情况。 幼虫的神经系统在担轮幼虫时期(受精后18h)开始发育,这时还不能检测到β肾上腺素受体。面盘幼虫时期(受精后1d)具备了顶神经节、脑神经节和脏神经节组成的中枢神经系统,在口附近有一些外周神经。β肾上腺素受体在受精后24h首次出现在面盘幼虫的顶神经节和脑神经节,分别命名为AR(apical receptor)和CR1(cerebral receptor 1)。 在受精后5d顶神经节已经检测不到。脑神经节和脏神经节由腹部向背部迁移,口的背腹两侧都出现了一些神经元。并且脏神经节周围也出现了一些神经细胞。AR在受精后3d就检测不到了。同时在CR1的后部新出现了一些β肾上腺素受体,命名为CR2。此后CR2发育迅速,在受精后5d就和CR1差不多大小。并且在CR1和CR2之间还出现了很多小的阳性信号。 变态过程中中枢神经系统中顶神经节消失了,并且出现了足神经节。另外,外套膜上出现了更多的外周神经。除了在稚贝的脑神经节和脏神经节外,在足、外套膜和水管上都有β肾上腺素受体存在。成体的鳃、足、心脏、水管、唇掰和外套膜上也有β肾上腺素受体分布。 变态信号传递到靶器官后,文蛤幼虫在形态结构和生态习性上开始了快速巨大的变化。其中幼虫的肌肉系统是变化最大的系统,并且直接与文蛤运动、摄食等习性转变相关。本文采用免疫组化的方法对文蛤幼虫肌肉系统的发育进行了研究。结果表明,文蛤幼虫具有由幼虫收缩肌、面盘收缩肌和闭壳肌组成的十分复杂的肌肉系统。幼虫收缩肌和前闭壳肌最早出现于担轮幼虫阶段(受精后18h)。孵化后幼虫的肌肉系统迅速发育,受精后22h幼虫的肌肉系统基本发育完全,并一直维持到变态前。变态过程中幼虫收缩肌和面盘收缩肌逐渐萎缩消失。同时,足收缩肌、后闭壳肌和外套膜肌肉等稚贝的肌肉系统快速形成。变态后稚贝幼虫收缩肌和面盘收缩肌完全消失,其肌肉系统由前后闭壳肌、足收缩肌和外套膜肌肉组成。
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The ciliate community in the Bohai Sea (China) was studied from 23 September to 7 October 1998. A hurricane struck the study area between the 2 grid station investigations; which were 6 d apart. The ciliate biomass decreased drastically after the hurricane. The surface ciliate biomass decreased from 0.2-12.3 to 0.02-2.8 mug C l(-1) and the water column ciliate biomass from 2-136 to 0.01-47 mg C m(-2). The ciliate biomass:chlorophyll ratios in the surface water were calculated to be 0.04 to 4.7 (1.41 on average) during the first grid investigation and 0.01 to 1.18 (0.26 on average) during the second grid investigation. Distinct patterns of temporal changes in ciliate abundances were found at different stations both before and after the hurricane.
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Me optimal conditions were established for the extraction of paralytic shellfish poisoning toxins from gonad of Chlamys nobills using acetic acid and hydrochloric acid in the concentration range of 0.04-1.0 mol/L. A 10-g portion of gonad of Chlamys nobilis was extracted by boiling for 5 min with 1.0 mL acetic acid and hydrochloric acid in a 50-mL beaker. Meanwhile, a portion of gonad of Chlamys nobilis was extracted by sonication in the solution of 0.3 mol/L HAc + 0.2 mol/L HCl for a total period of 5-30 min. The raw extract was centrifuged at 3500 r/min for 5 min and the pH of supernatant was adjusted from 2.0 to 4.0 by 0.1 mol/L NaOH or 5 mol/L HCL After passing through a Millipore ultrafiltration membrane (10000 MW cut-off), ultrafiltrate was then analyzed by HPLC. The results showed that hydrochloric acid in the concentration range of 0.25-1.0 mol/L caused a significant decrease of N-sulfocarbarnoyl-11-hydroxysulfate toxin C1 (C1), C2 and gonyautoxin 5 (GTX5) and the concomitant increase of GTX2,3. However, the amount of the three unstable toxins did not show any change using the extraction with acetic acid. Under the same concentration of acetic acid (0.3 mol/L) and hydrochloric acid (0.2 mol/L), the amount of C1 in the ultrasonic extraction was obviously lower than the boiling one, while C2 showed slightly higher than the latter.
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A geochemical study of Bohai Bay surface sediments was carried out to analyze the potential harmful element (PHE: Ge, Mo, In, Sn, Sb,Te, Tl, Bi and V) concentrations, transportation and deposition, enrichment factors and sources. Germanium, Mo, In, Sn, Sb, Te, Tl, Bi and V concentrations in the surface sediments were: 1.43-1.71, 0.52-1.43, 0.04-0.12, 2.77-4.14, 1.14-2.29, 0.027-0.085, 0.506-0.770, 0.27-0.63 and 70.35-115.90 mu g/g, respectively. The distributions of total PHE concentrations, together with sequential extraction analyses, showed that the PHEs were mainly due to natural inputs from the continental weathering delivered to the bay by rivers and atmospheric transportation and deposition. However, high Mo, Sb, Te, Bi and V occurred in non-residual fractions, suggesting some anthropogenic inputs in addition to the natural inputs. Besides sources, the distributions of PHEs were influenced by the coupling of physical, chemical and biological processes. Enrichment factor (EF) was computed for each site for each element in order to assess the polluting elements and the degree of pollution at each site. Results revealed that the EFs were generally lower than 1.0, particularly for Ge, Mo, In, Sn, Tl and V; however, the EFs were higher (>1.5), particularly for Sb, Te and Bi, revealing moderate contamination. (C) 2010 Elsevier B.V. All rights reserved.
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As a prelude to strain selection for domestication and future marker assisted selection, genetic variation revealed by microsatellite DNA was evaluated in yellow perch, Perca flavescens, from four wild North American populations collected in 2003-2004 (Maine, New York, North Carolina, and Pennsylvania,), and two captive populations (Michigan and Ohio). For the loci examined, levels of heterozygosity ranged from H-e=0.04 to 0.88, genetic differentiation was highly significant among all population pairs, and effective migration ranged from low (N(e)m=0.3) to high (N(e)m=4.5). Deviation from Hardy-Weinberg equilibrium was regularly observed indicating significant departures from random mating. Instantaneous measures of inbreeding within these populations ranged from near zero to moderate (median F=0.16) and overall inbreeding levels averaged F-IS=0.18. Estimates of genetic diversity, Phi(ST), and genetic distance were highest between Michigan and all other broodstock groups and lowest between New York and Ohio. Genetic differentiation among groups did not correlate with geographic distance. Overall, the patterns of variation exhibited by the captive (Michigan and Ohio) populations were similar to patterns exhibited by the other wild populations, indicating that spawning and management practices to date have not significantly reduced levels of genetic variation. (C) 2007 Elsevier B.V. All rights reserved.
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目的 建立了反相高效液相色谱法同时测定藏木香中土木香内酯和异土木香内酯的方法.方法 采用Phenomenex Kromasil C18色谱柱(4.6mm×250mm,5.0μm);流动相为乙腈-0.04%磷酸溶液(50:50);检测波长:194 nm;流速:1.0 mL•min~(-1).结果 异构体土木香内酯和异土木香内酯达到基线分离,含量测定的线性良好,线性范围和相关系数分别为0.07~4.80μg•L~(-1) (r=0.999 8),0.07~4.85μg•L~(-1) (r=0.999 8);回收率分别为97.5%和102.1%;方法精密度良好,RSD分别为1.56%和1.87%(n=5);方法重现性良好,RSD分别为1.67%和0.92%(n=5).结论 所建立的方法简便、快捷、准确,重现性好,可用于藏木香药材及其制剂的质量控制.
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目的建立了青海地区唐古特大黄药材的HPLC指纹图谱.方法采用反相高效液相色谱法,乙腈-水(0.04%的磷酸)为流动相,梯度洗脱,体积流量1.0 mL/min,检测波长为280 nm,柱温为40 C.结果精密度、重现性、稳定性试验中共有峰面积和保留时间的RSD均小于5%.青海不同采集地唐古特大黄的平均相似度为0.925.结论该方法简便、实用、可靠,可用于以青海果洛地区为主产地不同海拔唐古特大黄药材质量标准的分析检测,也为栽培大黄代替野生大黄提供理论基础.
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目的:建立反相高效液相色谱法同时测定刺芒龙胆植物不同部位落干酸、獐牙菜苦苷、龙胆苦苷的含量。方法:采用ZORBAX SB-C18(250mm×4.6mm,5μm)色谱柱,流动相为甲醇-水(含0.04%磷酸)的比例25:75,流速1mL·min^-1,检测波长238nm,柱温30℃。结果:3种成分均达到基线分离,落干酸、獐牙莱苦苷、龙胆苦苷的线性范围分别为0.039~1.56μg(r=0.9998),0.0725~1.45μg(r=0.9999),0.061~1.225μg(r=0.9997);回收率为101.3%(RSD=2.6%),98.7%(RSD=3.1%,99.6%(RSD=1.2%)。结论:测定方法快速,结果准确、可靠。
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目的:建立反相高效液相色谱法同时测定獐牙菜及其近缘植物中番木鳖酸、獐牙菜苦苷、龙胆苦苷、芒果苷的含量。方法:采用ZORBAX SB—C18(250 mm×4.6mm,5μm)色谱柱,以流动相甲醇和水(含0.04%磷酸)的比例在0-24 min内由22:78至38:62线性梯度洗脱,流速1 mL•min~1,检测波长254 nm,柱温30℃。结果:4种成分均达到基线分离,番木鳖酸、獐牙菜苦苷、龙胆苦苷、芒果苷的线性范围分别为0.05—6.25μg(r=0.9999),0.0095—2.9 μg(r=0.9998),0.0486—2.56μg(r=0.9999),0.0056—2.8μg(r=0.9998);回收率为102%(RSD=4.4%),97.7%(RSD=4.3%),99.5%(RSD=3.5%),103%(RSD=1.1%)。结论:方法测定快速,结果准确、可靠。
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对青海省玛多县境内的普通大鵟(Buteo hemilasius)的14个胃容物和118个食茧中的猎物逐个分析鉴定,共分为3种类型:①高原鼠兔(Ochotona curzoniae),②青海田鼠(Lasiopodomys fuscus),③小型鸟类。分别计算各类猎物出现率(pi)和生物量比率(b_i)。高原鼠兔、青海田鼠、小型鸟类在胃容物中,p_i分别为0.28、0.68和0.04;b_i则分别为0.59、0.40和0.02;食茧中,p_i分别为0.70、0.27和0.02,b_i则分别为0.89、0.10和0.01。x~2检验表明取食个体数和生物量在胃容物和食茧之间差异显著,但均说明高原鼠兔和青海田鼠等小型哺乳类是普通大鵟的主要食物来源。
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We investigated how the high small-scale species richness of an alpine meadow on the Qinghai-Tibet Plateau, China, is maintained. This area is characterized by strong wind and severe cold during long winters. In winter, most livestock is grazed on dead leaves in small pastures near farmers' residences, whereas in the short summer, livestock is grazed in mountainous areas far from farmers' residences. The number of plant species and the aboveground biomass were surveyed for three adjacent pastures differing in grazing management: a late-winter grazing pasture grazed moderately from 1 February to 30 April, an early-winter grazing pasture grazed lightly from 20 September to late October, and a whole-year grazing pasture grazed intensively throughout the entire year. In each pasture, we harvested the aboveground biomass from 80 or 100 quadrats of 0.01 m(2) along a transect and classified the contents by species. We observed 15.5-19.7 species per 0.01 m(2), which is high richness per 0.01 m(2) on a worldwide scale. The species richness in the two winter grazing pastures was higher than that in the whole-year grazing pasture. The spatial variation in species richness and species composition in the two winter grazing pastures in which species richness was high was greater than that in the whole-year grazing pasture in which species richness was lower. Most of the leaves that are preserved on the winter grazing pastures during summer are blown away by strong winds during winter, and the remaining leaves are completely exhausted in winter by livestock grazing. A pasture with a high richess is accompanied by a high spatial variation in species richness and species composition. There is a high possibility that the characteristic of spatial variation is also caused by traditional grazing practices in this area.
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The Alytn fault is a huge left-slip fault zone within the Asian continent, and locates such zone that is linked to main tectonic units in the western China, which makes it is very important to the tectonic framework and ore distribution in the western China. Selecting two ophiolite zones (namely Hongliugou-Lapeiquan ophiolite zone and Sulamutage ophiolite zone) respectively located within the southern and northern part of the Altyn fault and based on analysis of field geology characteristics and geochemistry, this paper recognized the rock types (mainly mafic and ultramafic rocks) within the melanges and subdivided each lithological unit based on tectonic environment. At last, this paper rebuilt the paleo-tectonic framework in the Alytn region by the method of tectonic facies and discussed its tectonic evolution with the theory of collision orogens. Combining former results with hard field observation and geochemical analysis, this paper acquired such recognitions to two ophiolte zones within the Altyn fault zone as follows: To the typical regions (Hongliugou, Lapeiquan, Mangya and Sulamutage) within the two ophiolte zones in the Altyn fault zone, this paper offered the field geology profiles. Field geology characteristics show that they are composed of melange bases (mainly abyssal flysch and carbonate rocks) and melange blocks from various tectonic environments, often with fault contact among each lithological units, belonging to typical ophiolitic melange zone. The ultramafic rocks outcropped at the Altyn region are all harzburgites. Remant grains of primary minerals have melted residual texture and elastic deformation texture under high temperature and pressure. The whole-rock analyses show their low TiO_2 contents (0.01~0.04%), low Al, Ca and high MgO contents and wide Mg~# range (89.35~95.57). Rare earth patterns have two types, namely tabacco pipe-shped and LREE-shaped, of which the former is often seen. The chondrite-nomalized Yb values of these analyses are all lower than 1. The spinels have low Ti and high Cr content and most spinels have Cr# higher than 60. All of the above characteristics show that the ultramafic rocks in the Altyn fault zone are components of metmorphic peridotites of ophiolite from depleted mantle source and most ophiolites from this zone belong to supra-subduction zone (SSZ) type ophiolite with a few mid-ocean ridge basalt (MORB) type. Geochemical analyses show that the melange blocks within the Altyn ophiolitic melange zone have different characteristics from various tectonic environments. This paper recognized such tectonic-lithological assemblages as mid-ocean basalts, oceanic island basalts, oceanic island arc tholeiites, island arc calalkaline basalts and island arc granites and inferred that these tectonic-lithological units respectively belongs to such tectonic units as ophiolites, oceanic islands and/or oceanic seamounts, oceanic island arc and a~creting arcs, which show these blocks from oceanic crust and subduction zone for the most part. For the Altyn ophiolites, the chronological data show they become new from the north to the south. Combined with the study on late slip of Altyn fault and North Qilianshan orogeny, the author inferred that the Altyn region had belonged to one part of the North Qilianshan accreting wedge-arc orogeny at paleozoic, and later huge left-slip made it locate modem site.
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Different conclusions from previous work are made from the geochemical study for the early Paleozoic volcanic rocks hosting massive sulfide deposits in the north Qilian Orogen. The main points are: (1)The geochemical characteristics of the basalts and rhyolites from the Baiyin deposit are not consistent with that of the volcanic rocks in the continental rift setting, but show the relationship with subduction. The basalts and rhyolites from the Baiyin deposit are probably individual tectonic slice piled by subduction, and there is no bimodal volcanic rock suite occurred in the Baiyin deposit. Zircon U-Pb dating constrains the magmatic emplacement of basalts and rhyolites at 475±10Ma and 453±12Ma, respectively. The basalts are characterized by enriched Th and Sr, and depleted Nb, Ta and Ti. They have relatively high Th/Nb ratios between 0.9 and 1.3. Their εNd(T) values vary from -1.2 to +3.4. The chemical and isotopic compositions display a typical subduction-related signature, and they suggest that an enriched component with the isotopic composition of EMII might have contributed to the generation of the Baiyin basalts. The basalts were likely formed in a mature island-arc or a volcanic arc built on comparatively young or thin continental crust in an active continental margin. The rhyoIites have low concentrations of LILE compared to the basalts. They do not seen to have a relationship with the basalts, because of their significantly higher εNd(T) values (+4.3~+7.7). The high and positive εNd(T) values also rule out their derivation from anatexis of the continental crust. A modeling study suggests that the source.of the Zhe-Huo and Xiaotieshan rhyolites is similar to boninite and IAT (island-arc tholeiite), and hence indicating an intra-oceanic arc environment. (2) The formation of the Shangliugou volcanic rocks from .Qilian area is also related to subduction. The basaltic andesite have low TiO_2(0.45~0.63%) and P_2O_5(0.04~0.09) content, and high Th/Nb ratios (0.3~0.6). They show flat REE patterns. Their εNd(T) values vary in a narrow range from +4.8 to +6.4. The chemical and isotopic compositions indicate that they are derived from a slightly depleted mantle source and are fromed in intra-island arc setting. The rhyolites show calc-alkaline trend. They show enriched LREE and fiat HREE patterns with obvious negative Eu anomaly. They have high Th/Ta ratios (5.0 ~ 11.7) and large negative εNd(T) values (-2.6 ~ -8.4). The rhyolites are formed in active continental margin and result from a mixed process of two endmembers, or crust assimilation. (3) The metal elements of the volcanic-hosted massive sulfide deposit have two sources, the copper and zinc are derived from rhyolitic magmas whereas the lead are probably related to old sediments overlying the rhyolites. (4) It is suggested here that the volcanic rocks hosting massive sulfide deposit in the north Qilian orogen, which are previously considered as a bimodal suite of Neo-proterozoic to middle Cambrian age in a continental rift, are virtually related to subduction magmatism in Ordovician age, and there might have no continental rift magmatism of Neo-proterozoic to middle Cambrian in the north Qilian.
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近年来,随着多接收电感耦合等离子体质谱 (MC-ICP-MS)逐渐应用,过渡族金属(Cu,Zn 和Fe 等)同位素测试方法逐渐成熟,测定精度可达0.04‰,使得铜锌铁等同位素地球化学研究成为近年来国际地学研究领域的热点。本文对铜锌同位素的测试方法、分馏机理及其在环境地球化学研究领域的应用进行了较系统综述。