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181.
The regional dynamical model of the atmospheric ozonosphere 总被引:1,自引:0,他引:1
TheRegionalDynamicalModeloftheAtmosphericOzonosphereWangWeiguo(王卫国),XieYingqi(谢应齐)DepartmentofEarthscience.YunnanUniversity,K... 相似文献
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183.
Patinopecten yessoensis is a commercial valuable species. This study deals with the effect of nutrient effects of the broodstock(mainly ovaries) on the larvae. Concentrations of total carbohydrate, total protein and total lipid in the gonads of P. yessoensis from three Hatcheries(Hatchery 1, Hatchery 2, and Hatchery 3) were determined before and after spawning. The relationship between the nutrient concentration in ovaries before spawning(BC) and that of larvae(LC) was assessed as well as the change in nutrient levels in ovaries after spawning(DC). Results indicate that the BC of total carbohydrate(7.66%) and total lipid(14.48%) in ovaries were significantly higher than in testes(5.20%, 5.20% respectively), whereas the BC of total protein in the ovaries was lower(61.76%) than in the testes(81.67%). The different gonadal composition suggests the different nutrient demands between male and female broodstocks in breeding season. P atinopecten yessoensis gonads contained a higher proportion of lipids, in comparison to other bivalves, which might be a response to the low ambient water temperatures. Further analysis of fatty acids showed that the concentrations of n-3PUFA, EPA and DHA in larvae(LC) were positively correlated with BC and DC, indicating the significant nutrient influence of broodstocks on the larvae. As these fatty acids are important in metabolism, and have been demonstrated to be influential to the viability of the larvae, larval growth and the settlement, spat growth, and juvenile survival in many bivalves, they could possibly be used as indexes to evaluate, and predict condition of broodstocks and larvae. 相似文献
184.
Artificial lighting regimes have been successfully used to inhibit sexual maturity of Atlantic salmon in confinement.However,when these operations are applied in commercial recirculating aquaculture systems(RAS) using standard lighting technology,sexual maturation is not suppressed.In this study,an L_9(3~3) orthogonal design was used to determine the effects of three factors(spectral composition,photoperiod,and light intensity) on the gonadal development of Atlantic salmon in RAS.We demonstrated that the photoperiod at the tested levels had a much greater effect on the gonadosomatic index and female Fulton condition factor than spectral composition and light intensity.The photoperiod had a significant effect on the secretion of sex steroids and melatonin(P0.05),and a short photoperiod delayed sex steroid and melatonin level increases.The three test factors had no significant effects on the survival rate,specific growth rate,relative weight gain,and male Fulton condition factor(P0.05).The optimum lighting levels in female and male Atlantic salmon were LD 8:16,455 nm(or 625 nm),8.60 W/m~2;and LD 8:16,8.60 W/m~2,455 nm respectively.These conditions not only delayed gonadal development,but also had no negative effects on Atlantic salmon growth in RAS.These results demonstrate that a combination of spectral composition,photoperiod and light intensity is effective at delaying the gonadal development of both male and female salmon in RAS. 相似文献
185.
扬子克拉通北缘中元古代—新元古代地质构造演化一直是地学界研究的热点。本文报道了大别造山带红安地块康家湾混杂岩中榴闪岩岩块和含石榴子石白云钠长片岩基质中锆石U-Pb年龄和Hf同位素组成。结果表明,康家湾混杂岩中榴闪岩岩块的原岩形成时间为1064±10 Ma,且经历了183±3 Ma的流体作用过程;中元古代锆石Hf同位素组成(εHf(t)=4.7~12.3)接近当时的亏损地幔值,指示榴闪岩原岩(玄武质岩石)可能来自亏损的地幔源区部分熔融作用;混杂基质中碎屑锆石年龄谱可大致分为2576 Ma、2065~1698 Ma、1071~560 Ma和254~156 Ma四组,暗示其物源可能主要来自于近源的秦岭-大别造山带前寒武纪基底;基质中最年轻的岩浆锆石年龄为~240 Ma,表明康家湾混杂岩的最终就位时间可能在晚三叠世到早侏罗世之间。综合秦岭-大别造山带新元古代构造演化过程,本研究认为大别造山带红安地块与扬子克拉通庙湾蛇绿岩、神农架弧等共同构成了一套中元古代末期—新元古代早期岛弧增生造山体系,从而支持扬子克拉通可能由一系列微陆块逐渐拼合而成。 相似文献
186.
地层水化学特征及流体成因的分析对油气成藏的研究具有重要意义,对库车坳陷克拉苏构造带的地层水化学特征及流体成因的研究有助于油气藏的勘探开发。塔里木盆地库车坳陷克拉苏构造带构造特征复杂,地层水化学特征及流体系统缺乏系统研究。为了明确克拉苏构造带地层水化学特征及其流体系统,对地层水的溶解性总固体(TDS)、离子比例系数及压力分布特征进行了分析。研究结果表明:克拉苏构造带地层水以高TDS的卤水为主(平均值为154.92 g/L),按照苏林分类主要为CaCl2型,按照舒卡列夫分类为Cl-Na型和Cl-Na·Ca型,为典型的沉积埋藏水。地层水的脱硫系数较低(平均值小于1.2)、变质系数较高(平均值大于6),表明地层的封闭性较好,地层水经历了较强的水岩反应。参照地层压力场、岩性特征及地层水特征,将库车凹陷克拉苏构造带划分为第四系—新近系、古近系、白垩系、侏罗系及下伏地层四套流体系统。结合研究区岩性组成、构造演化特征及地层水化学特征分析,明确了白垩系巴什基奇克组地层水的成因为白垩系原始沉积水与侏罗系烃源岩生烃时排出的有机物转化流体、沉积水及古近系膏盐层高盐度流体的混合。 相似文献
187.
Evidence for high‐temperature fractionation of lithium isotopes during differentiation of the Moon 下载免费PDF全文
James M. D. Day Lin Qiu Richard D. Ash William F. McDonough Fang‐Zhen Teng Roberta L. Rudnick Lawrence A. Taylor 《Meteoritics & planetary science》2016,51(6):1046-1062
Lithium isotope and abundance data are reported for Apollo 15 and 17 mare basalts and the LaPaz low‐Ti mare basalt meteorites, along with lithium isotope data for carbonaceous, ordinary, and enstatite chondrites, and chondrules from the Allende CV3 meteorite. Apollo 15 low‐Ti mare basalts have lower Li contents and lower δ7Li (3.8 ± 1.2‰; all uncertainties are 2 standard deviations) than Apollo 17 high‐Ti mare basalts (δ7Li = 5.2 ± 1.2‰), with evolved LaPaz mare basalts having high Li contents, but similar low δ7Li (3.7 ± 0.5‰) to Apollo 15 mare basalts. In low‐Ti mare basalt 15555, the highest concentrations of Li occur in late‐stage tridymite (>20 ppm) and plagioclase (11 ± 3 ppm), with olivine (6.1 ± 3.8 ppm), pyroxene (4.2 ± 1.6 ppm), and ilmenite (0.8 ± 0.7 ppm) having lower Li concentrations. Values of δ7Li in low‐ and high‐Ti mare basalt sources broadly correlate negatively with 18O/16O and positively with 56Fe/54Fe (low‐Ti: δ7Li ≤4‰; δ56Fe ≤0.04‰; δ18O ≥5.7‰; high‐Ti: δ7Li >6‰; δ56Fe >0.18‰; δ18O <5.4‰). Lithium does not appear to have acted as a volatile element during planetary formation, with subequal Li contents in mare basalts compared with terrestrial, martian, or vestan basaltic rocks. Observed Li isotopic fractionations in mare basalts can potentially be explained through large‐degree, high‐temperature igneous differentiation of their source regions. Progressive magma ocean crystallization led to enrichment in Li and δ7Li in late‐stage liquids, probably as a consequence of preferential retention of 7Li and Li in the melt relative to crystallizing solids. Lithium isotopic fractionation has not been observed during extensive differentiation in terrestrial magmatic systems and may only be recognizable during extensive planetary magmatic differentiation under volatile‐poor conditions, as expected for the lunar magma ocean. Our new analyses of chondrites show that they have δ7Li ranging between ?2.5‰ and 4‰. The higher δ7Li in planetary basalts than in the compilation of chondrites (2.1 ± 1.3‰) demonstrates that differentiated planetary basalts are, on average, isotopically heavier than most chondrites. 相似文献
188.
189.
利用2013年台风“苏力”的监测资料、台风灾情资料、2000年后福建省台风灾害数据库资料和台风“苏力”灾害防御行为效益评估网络问卷调查资料,采用相似分析法的上下限区间估算法,预评估台风“苏力”造成的受灾人口和直接经济损失,并利用台风灾害风险区划方法,对台风“苏力”进行灾害风险区划。结果表明:台风“苏力”预评估结果与实际灾情相符,台风“苏力”灾害风险分布与实际灾情分布大部分一致,风险等级高的县市,实际灾情重,高风险区的大部县市直接经济损失均为1000万元以上。应用台风灾害防御行为效益评估三级指标体系,通过调查统计分析可知,指标体系中的各级各项指数均能较好地反映和评估政府主导、部门联动和公众参与的防御行为效益,政府主导在各类减灾行为中作用最大。 相似文献
190.
We present a quantitative model of the magnetic energy stored and then released through magnetic reconnection for a flare on 26 February 2004. This flare, well observed by RHESSI and TRACE, shows evidence of non-thermal electrons for only a brief, early phase. Throughout the main period of energy release there is a super-hot (T?30 MK) plasma emitting thermal bremsstrahlung atop the flare loops. Our model describes the heating and compression of such a source by localized, transient magnetic reconnection. It is a three-dimensional generalization of the Petschek model, whereby Alfvén-speed retraction following reconnection drives supersonic inflows parallel to the field lines, which form shocks: heating, compressing, and confining a loop-top plasma plug. The confining inflows provide longer life than a freely expanding or conductively cooling plasma of similar size and temperature. Superposition of successive transient episodes of localized reconnection across a current sheet produces an apparently persistent, localized source of high-temperature emission. The temperature of the source decreases smoothly on a time scale consistent with observations, far longer than the cooling time of a single plug. Built from a disordered collection of small plugs, the source need not have the coherent jet-like structure predicted by steady-state reconnection models. This new model predicts temperatures and emission measure consistent with the observations of 26 February 2004. Furthermore, the total energy released by the flare is found to be roughly consistent with that predicted by the model. Only a small fraction of the energy released appears in the super-hot source at any one time, but roughly a quarter of the flare energy is thermalized by the reconnection shocks over the course of the flare. All energy is presumed to ultimately appear in the lower-temperature (T?20 MK) post-flare loops. The number, size, and early appearance of these loops in TRACE’s 171 Å band are consistent with the type of transient reconnection assumed in the model. 相似文献