Mg-Al-Mn-RE系合金组织与性能研究

利用金属型铸造制备了Mg-5Al-0.3Mn-xRE (x = 0~4, wt%，RE = Ce, Nd, Sm, Y和(CeLa)混合稀土)系列合金，研究了铸态合金的组织和力学性能。利用轧制和挤压技术对优化出的合金进行了变形加工处理，并研究了合金加工后的组织和力学性能。 对于铸态合金，稀土元素不仅可以细化合金的晶粒，而且形成不同类型的Al-RE化合物，含Ce的合金中生成Al11Ce3相，含Nd或Sm的合金中，主要生成Al11Nd3 (Al11Sm3)相和少量的Al2Nd (Al2Sm)相，含Y的合金中生成Al2Y相。另外，添加稀土可以改变Mg17Al12相的形貌，使其变得更加细小、弥散。添加适量的稀土可以明显提高铸态合金在室温和150℃下的力学性能，Mg-5Al-0.3Mn-1.5Ce, Mg-5Al-0.3Mn-2Nd和Mg-5Al-0.3Mn-2Sm合金在各自的体系中具有最佳的综合力学性能。合金力学性能提高的主要原因是细晶强化、Al-RE化合物第二相强化以及减弱Mg17Al12相对合金高温力学性能的不利影响。 对Mg-5Al-0.3Mn-(1.0, 1.5, 2.0)Ce，Mg-5Al-0.3Mn-2Nd，Mg-5Al-0.3Mn-1.5(CeLa)和Mg-5Al-0.3Mn-3Y合金在300-400℃下进行了热轧制或挤压变形，与铸态合金相比，轧制和挤压合金具有更高的力学性能。轧制合金的室温抗拉强度为290-340 MPa，较铸态合金提高约50％，屈服强度约为210-260 MPa，较铸态合金提高约2倍。挤压态合金的抗拉强度为260-270 MPa，屈服强度为160-190MPa，伸长率为20-22％；150℃的力学性能也得到了明显改善。 结合热力学计算、合金化元素之间的电负性差、化合物相的生成焓数据以及相图计算，阐述了稀土化合物相的生成机制，稀土元素与Al元素之间的电负性差大于其与Mg之间的电负性差，且Al-RE相的生成焓远低于Mg-RE和Mg-Al相的生成焓，因此在Mg-Al合金中加入RE后，RE优先与Al形成Al-RE化合物。从晶粒细化、化合物强化相的生成和演变、变形加工处理的位错交互作用等方面讨论了合金的强化机制，认为细晶强化、第二相强化及形变强化是提高合金力学性能的主要机制。

florisil柱净化玉米、水稻及糙米中黄曲霉毒素的最优化条件研究

研究了利用florisil柱净化玉米、水稻及糙米中黄曲霉毒素的最优化条件.两种粒度的florisil填充柱净化玉米均较理想,但粒度150～250μm的florisil对水稻及糙米的净化影响较大,建议选用较小粒度的florisil材料.大粒度的florisil能减小溶剂的流速,用不同的溶剂淋洗杂质,最佳流速有所不同,氯仿-正己烷(体积比1∶1)的最佳流速是1.55mL·min-1,而氯仿-甲醇(体积比9∶1)的最佳流速是0.68mL·min-1.

Vc二步发酵新组合菌系B_(15-14)的筛选及其条件优化

筛选出了一组Vc二步发酵的新组合菌系(命名为B15-14),研究了环境因子对新菌系产酸的影响。结果显示:新组合菌系的最适底糖浓度为7%;温度为29~33℃,31℃为最适;适当增加通气量(20~30 mL装液量,250 mL三角瓶)有利于产酸;起始pH值范围为6.0~7.5;以B t菌做伴生菌时,发酵40 h就已达到终点,明显缩短了发酵时间。

过去2000年中国东部地区的极端旱涝事件变化

利用据历史文献中汉代以来的旱涝灾害记载重建的逐年旱涝等级,结合已重建的东部地区干湿指数序列,通过定义判别历史时期极端旱涝事件的标准,分华北、江淮和江南3个区域辨识了过去2000年的重大旱涝事件。结果表明,各个区域的重大旱、涝多发时段分别是:华北地区出现在100～150年、550～650年、1050～1100年与1850～1900年;江淮地区出现在250～450年与1600～1850年;江南出现在350～400年、1100～1200年与1900～1950年。整个东部地区则出现在100～150年、250～35

用辐射方法制备PCL/玻璃纤维布和PCL/碳纤维布复合材料以及它们的生物降解性研究

观察了聚已内酯 (PCL) /玻璃纤维布和PCL/碳纤维布的机械性能的变化 ,通过对辐射交联的方法制备出了可生物降解聚合物涂覆纤维布复合材料。结果表明 ,γ辐射提高了复合材料的机械性能 ,这是由于所涂覆聚合物交联所产生的凝胶所致。在过冷态下通过γ射线照射 2 70kGy的PCL/玻璃纤维布复合材料的弯曲强度是未辐照样品的 1.5倍 ,弯曲模量提高到 1.35倍。通过酶降解试验和土埋法降解实验的研究 ,可以观察到降解导致了样品的失重。在酶降解试验中2 3h后 ,对于未交联材料涂覆的PCL完全降解掉 ,而交联样品中的PCL有 5 4%的失重发生。同样 ,在土埋法降解实验中 ,交联和未交联样品在一定的土埋时间后 ,也产生了样品的失重。未交联样品的失重率大于交联样品 ,这是由于交联样品所含有的交联网络结构阻碍它的降解。

950℃、1.0～3.5GPa下斜长角闪岩脱水熔融——压力和时间对结构的影响

利用YJ-3000t和JL-3600t多顶砧压力机,以哀牢山造山带南部红河县大白能—乐育剖面上的天然块状斜长角闪岩为初始样品,在950℃、1.0～3.5GPa、恒温20～300h条件下进行了两个系列的斜长角闪岩块状样品脱水部分熔融实验:(1)保持温度T=950℃,加热时间t=100h不变,改变压力(1.0～3.5GPa)的实验;(2)保持温度T=950℃,压力p=3.0GPa不变,改变加热时间(20～300h)的实验。结果表明,1.0～3.5GPa、950℃、恒温100h的条件下,随压力升高,斜长角闪岩中依次生成了单斜辉石+石榴石+熔体的矿物组合(1.0～1.5GPa)和单斜辉石+石榴石+熔体+硬玉+SiO2矿物+蓝晶石(2.0～3.5GPa)的矿物组合。3.0GPa、950℃条件下,随加热时间增加,实验产物中依次生成了单斜辉石+石榴石+熔体+硬玉+SiO2矿物+蓝晶石的矿物组合(20～100h)和单斜辉石+石榴石+熔体的矿物组合(150～300h)。斜长角闪岩的原岩结构决定了实验产物中新生矿物和熔体的分布。依据实验产物的矿物组合和新生矿物的分布特征,讨论了950℃、1.0～3.5GPa、恒温(20～300h)条件下,斜长角闪岩部分熔融过程的结构变化、变质反应以及石榴石冠状体的成因。

会泽铅锌矿床成矿流体浓缩机制

云南会泽铅锌矿床位于扬子板块西缘川-黔-滇铅锌银多金属成矿域的中南部，严格受断裂带的控制．长期以来，对于该矿的成矿流体来源存在着较大的争论．研究表明，矿石中脉石矿物方解石的C、O同位素组成相对均一，其δ^13C(PDB)为-2．1×10^-3～-3．5×10^-3极差-1．4×10^-3、均值-2．8×10^-3，δ^18O(SMOW)为16．7×10^-3～18．6×10^-3、极差1．9×10^-3、均值17．7×10^-3，不同矿体(不同标高)、不同产状以及相同矿体不同产状方解石的C、O同位素组成不具明显差别；除了纯液相包裹体(L)和富液相的气液两相包裹体(L+V)外，还存在含子晶的三相包裹体(S+L+V)和不混溶的CO2三相包裹体(VCO2+LCO2+LH2O)，流体包裹体均一温度介于110～400℃之间，具有双峰现象；矿床的(^87Sr／^86Sr)0(0．713676-0．717012)不仅明显高于地幔(0．704±0．002)和峨嵋山玄武岩(0．703932～0．707818；85件样品)的(^87Sr／^86Sr)0，也相对高于矿区赋矿地层(C16)的(^87Sr／^86Sr)。(0．70868～0．70931；3件样品)，但明显低于基底岩石的(^87sr／^86Sr)。(0．7243～0．7288；5件样品)，且成矿过程中流体基本没有发生Sr同位素分馏现象．因此，成矿流体为均一流体，是不同性质流体的混合产物，具有多源性．而从气液两相包裹体盐度-均一温度图解可以看出，在300-400℃区间，包裹体盐度基本被孤立为两群：一群为5％～6％(w(NaCl))，另一群为12％～16％(w(NaCl))．而在100300℃特别是150-250℃区间，包裹体盐度则基本均匀分布在7％～23％(w(NaCl))之间．断裂带形成压力为(50～320)×10^5Pa，矿体上覆岩石压力为(574-640)×10%5Pa，矿床成矿压力为(145-754)×10^5Pa．流体在上升到断裂带后压力的剧降，导致了沸腾作用的发生．在混合作用和沸腾作用的双重影响下，受狭窄断裂带控制的成矿流体高度浓缩，金属矿物得以大规模地从流体中沉淀出来，形成品位极高的铅锌矿石．

Direct detection of Yersinia pestis from the infected animal specimens by a fiber optic biosensor

The FOB-3, anew type fiber optic biosensor, is designed to rapidly detect a variety of biological agents or analytes with better stability, sensitivity and specificity. In order to detect Y. Pestis, a sandwich immunoassay was developed by using the purified antibody against antigen FI immobilized on polystyrene probes as the capture antibody and the monoclonal antibody-Cy5 conjugate as the detector. After a series of optimization for the stability, sensitivity and specificity of the FOB-3, 50-1000 ng/ml of antigen FI and 6 x 10(1)-6 x 10(7) CFU/ml Y. pestis could be detected constantly in about 20 min, and Y pestis could be detected specifically from Y. pseudotuberculosis, Y. enterocolitica, B. anthracis and E. coli. Then, 39 blind samples, including 27 tissues of mice infected with Y pestis and 12 tissues of healthy mice as negative control, were detected with the FOB-3. 92.6% infected tissues were identified from the tissues of healthy mice and the tissues containing more than 100 CFU/ml bacteria could be detected by the biosensor. The results demonstrated the feasibility of the FOB-3 as an effective method to detect Y. pestis rapidly and directly from the infected animal specimens with the advantage of portability, simple-operation as well as high sensitivity and specificity. (c) 2006 Elsevier B.V. All rights reserved.

渤海南部 Lz908 孔250 ka 以来的环境演化研究

本文主要针对 250 ka 以来渤海南部Lz908 孔的沉积序列进行年代学和沉积 学研究，通过年代框架的建立、环境代用指标的意义解读，并与区域和全球变 化相对比，讨论了渤海南部晚中更新世以来的环境过程和驱动因素。主要结论 如下： 1. 沉积物粒度对比试验表明，是否去除碳酸盐，对于渤海南部海岸带沉积 物的粒度分析结果产生了显著的影响。未去除碳酸盐的沉积物样品，显著增加 了黏土粒级、超细粒组分的含量；但就粒度分布而言，是否去除碳酸盐不会改 变粒度分布的基本形态。通过实验对比，我们认为，粒度测量的前处理过程去 除碳酸盐是必要的。 2. 粒度参数的计算方法主要有图解法和矩值法两种，为了比较不同方法计 算结果的差异，利用LZ908 孔岩心，在粒度分析的基础上，综合运用相关分析、 回归分析、聚类分析等统计方法，从参数计算过程、沉积物粒度分布形态（多 峰态粒度特征）等方面讨论了两种参数估计方法对计算结果的可能影响及其影 响因素。结果表明：平均粒径、标准偏差相互替代的程度高，而偏度、峰度相 互替代的程度低，或者不可替代；两者的差异是由各自本身的计算过程引起的， 是沉积物粒度分布特征的一种反映，并且与沉积水动力条件密切相关。 3. 释光年代学的研究表明，钻孔0-25 米内未见大的沉积间断，可以通过线 性内插的方式获得各个层位的年龄。25-54 米的海相地层，因为钻孔位于构造 稳定的沉降区，沉积物源单一，因此通过线性外推获得年龄。确定钻孔海侵层 渤海南部Lz908 孔250 ka 以来的环境演化研究 的底部年龄为为 250 ka。根据建立的渤海地区首条释光标准生长曲线，推测光 释光简单多片再生剂量法的理论测年上限为350 ka。 4. 粒度、磁化率等指标间的关系，以及区域和全球的对比表明：沉积物中 细颗粒组分代表了夏季风的变化，但细颗粒含量增高时，指示了夏季风的强盛， 反之则减弱；粗颗粒组分含量和磁化率与冬季风相关，粗颗粒组分含量增加、 磁化率升高时，代表了冬季风的强盛，反之则弱；与黄土-古土壤序列、石笋氧 同位序列和深海氧同位素序列在轨道尺度上对比良好；沉积序列包含27 ka 和 126 ka 的显著周期成分，暗示了区域环境变化是由太阳辐射驱动控制的。

Manipulation of host density affects infestation of a peritrich ciliate (Epistylis lacustris) on a calanoid copepod (Leptodiaptomus minutus) in Crystal Lake, Wisconsin, USA

Specimens of the calanoid copepod, Leptodiaptomus minutus, collected in June 1994 in oligotrophic: north temperate Crystal Lake, were infested with the stalked ciliate Epistylis lacustris. E. lacustris was highly specific to L. minutus and no other coexisting zooplankters were infested. Excluding nauplii, nearly 70% of copepods carried 1-20 ciliates, although the maximum load was as high as 250 ciliates. A lower percentage of nauplii were infested by the ciliate; those that were infested had a lower ciliate load than other copepod stages. Infestation by ciliates had no significant influence on the average egg number of female copepods. In a field experiment, higher copepod densities in enclosures resulted in a significantly higher infestation rate, but the ciliate load per individual copepod did not differ significantly among treatments.

超声化学法合成稀土纳米材料

稀土纳米材料因其独特的光、电、磁和催化等性能，在纳米器件和功能材料等诸多领域具有重要的应用价值。大量研究表明，纳米材料的物理和化学性质与其尺寸、成分、形貌和晶型密切相关。稀土纳米材料的合成方法有许多，然而，要真正实现这类材料的简单可控合成仍然是个艰难的课题。超声化学法由于具有操作简单、合成周期短、反应温度低、成本低廉并且产物均匀、粒径分布窄和纯度高等突出优点，已经在无机纳米材料制备领域中显示出独特的魅力。因此，本论文的工作是运用超声化学法合成有广泛应用前景的稀土纳米材料，对产物的形貌和粒径进行有效的调控，研究和分析其形成机理，并进一步考察其形貌、结构与性能之间的相互关系。 在本论文中，我们研究的体系集中在稀土磷酸盐、稀土氟化物和稀土钒酸盐三类纳米材料。 采用超声化学法得到的CePO4:Tb和CePO4:Tb/LaPO4(核/壳)纳米棒结晶完好，具有CePO4体材料的六方相结构。CePO4:Tb纳米棒直径为10-30 nm，长度为200 nm，CePO4:Tb/LaPO4(核/壳)纳米棒的LaPO4壳的厚度为2-10 nm。CePO4:Tb和CePO4:Tb/LaPO4(核/壳)纳米棒均具有Ce3+ (5d - 4f)和Tb3+ 5D4-7FJ(J = 6-3)的特征发射。与CePO4:Tb纳米棒核相比，CePO4:Tb/LaPO4(核/壳)纳米棒的光谱强度及荧光寿命均有较大的提高，这是由于形成核/壳结构后发光中心镧系金属离子与表面淬灭中心的距离增大，减少了能量传递过程中非辐射复合的路径，使能量淬灭受到抑制。 采用简单、快速、无模板辅助的超声化学法合成了稀土氟化物，并对产物的形貌和粒径进行了有效的调控。通过应用不同氟源(KBF4、NaF和NH4F)选择性合成了具有不同形貌的CeF3纳米材料，如片状、棒状和颗粒状。对具有不同形貌的CeF3样品进行了UV-Vis吸收光谱和荧光光谱测试和比较。研究结果表明不同形貌的样品，它们的光学性质存在很大差异，这说明纳米材料的光学性质与其形貌、粒径、晶体结构等因素有密切的关系。得到的EuF3单晶纳米材料具有三维花状形貌。这些纳米花的外形为球状，平均直径为0.9 μm-1.0 μm，每个花瓣的厚度约为0.14 μm。在其他实验条件不变的情况下，采用搅拌法而不经过超声辐射的对比实验只能得到二维纳米片，这表明超声辐射对花状EuF3的形成起到了至关重要的作用。基于不同反应时间的实验结果，我们提出了这种三维花状EuF3纳米材料可能的形成机理。 采用超声化学法选择性地合成了介孔及棒状CeVO4和纺锤状的YVO4:Eu3+ 纳米材料。CeVO4纳米棒的平均直径为5 nm，长度为150 nm。介孔CeVO4材料的比表面积较高(122 m2•g-1)，孔径分布窄，其催化性能有望得到提高。纺锤状的YVO4:Eu3+ 纳米粒子具有四方相锆石结构，其直径为90-150 nm，长度为250-300 nm。超声辐射对样品的形貌起着关键作用，在其他反应条件不变，未采用超声辐射的情况下只能得到团聚严重的纳米颗粒。荧光测试表明，纺锤状YVO4:Eu样品表现为Eu3+ 5D0-7FJ(J = 1- 4)的特征跃迁，以5D0-7F2电偶极跃迁(614nm)为最强峰，属于红光发射。

青藏高原及邻区面波频散反演--岩石圈-软流层体系结构研究

The Qinghai-Tibet Plateau lies in the place of the continent-continent collision between Indian and Eurasian plates. Because of their interaction the shallow and deep structures are very complicated. The force system forming the tectonic patterns and driving tectonic movements is effected together by the deep part of the lithosphere and the asthenosphere. It is important to study the 3-D velocity structures, the spheres and layers structures, material properties and states of the lithosphere and the asthenosphere for getting knowledge of their formation and evolution, dynamic process, layers coupling and exchange of material and energy. Based on the Rayleigh wave dispersion theory, we study the 3-D velocity structures, the depths of interfaces and thicknesses of different layers, including the crust, the lithosphere and the asthenosphere, the lithosphere-asthenosphere system in the Qinghai-Tibet Plateau and its adjacent areas. The following tasks include: (1)The digital seismic records of 221 seismic events have been collected, whose magnitudes are larger than 5.0 over the Qinghai-Tibet Plateau and its adjacent areas. These records come from 31 digital seismic stations of GSN , CDSN、NCDSN and part of Indian stations. After making instrument response calibration and filtering, group velocities of fundamental mode of Rayleigh waves are measured using the frequency-time analysis (FTAN) to get the observed dispersions. Furthermore, we strike cluster average for those similar ray paths. Finally, 819 dispersion curves (8-150s) are ready for dispersion inversion. (2)From these dispersion curves, pure dispersion data in 2°×2° cells of the areas (18°N-42°N, 70°E-106°E) are calculated by using function expansion method, proposed by Yanovskaya. The average initial model has been constructed by taking account of global AK135 model along with geodetic, geological, geophysical, receiving function and wide-angle reflection data. Then, initial S-wave velocity structures of the crust and upper mantle in the research areas have been obtained by using linear inversion (SVD) method. (3)Taking the results of the linear inversion as the initial model, we simultaneously invert the S wave velocities and thicknesses by using non-linear inversion (improved Simulated Annealing algorithm). Moreover, during the temperature dropping the variable-scale models are used. Comparing with the linear results, the spheres and layers by the non-linear inversion can be recognized better from the velocity value and offset. (4)The Moho discontinuity and top interface of the asthenosphere are recognized from the velocity value and offset of the layers. The thicknesses of the crust, lithosphere and asthenosphere are gained. These thicknesses are helpful to studying the structural differentia between the Qinghai-Tibet Plateau and its adjacent areas and among geologic units of the plateau. The results of the inversion will provide deep geophysical evidences for studying deep dynamical mechanism and exploring metal mineral resource and oil and gas resources. The following conclusions are reached by the distributions of the S wave velocities and thicknesses of the crust, lithosphere and asthenosphere, combining with previous researches. (1)The crust is very thick in the Qinghai-Tibet Plateau, varying from 60 km to 80 km. The lithospheric thickness in the Qinghai-Tibet Plateau is thinner (130-160 km) than its adjacent areas. Its asthenosphere is relatively thicker, varies from 150 km to 230 km, and the thickest area lies in the western Qiangtang. India located in south of Main Boundary thrust has a thinner crust (32-38 km), a thicker lithosphere of about 190 km and a rather thin asthenosphere of only 60 km. Sichuan and Tarim basins have the crust thickness less than 50km. Their lithospheres are thicker than the Qinghai-Tibet Plateau, and their asthenospheres are thinner. (2)The S-wave velocity variation pattern in the lithosphere-asthenosphere system has band-belted distribution along east-westward. These variations correlate with geology structures sketched by sutures and major faults. These sutures include Main Boundary thrust (MBT), Yarlung-Zangbo River suture (YZS), Bangong Lake-Nujiang suture (BNS), Jinshajiang suture (JSJS), Kunlun edge suture (KL). In the velocity maps of the upper and middle crust, these sutures can be sketched. In velocity maps of 250-300 km depth, MBT, BNS and JSJS can be sketched. In maps of the crustal thickness, the lithospheric thickness and the asthenospheric thickness, these sutures can be still sketched. In particular, MBT can be obviously resolved in these velocity maps and thickness maps. (3)Since the collision between India and Eurasian plate, the “loss” of surface material arising from crustal shortening is caused not only by crustal thickening but also by lateral extrusion material. The source of lateral extrusion lies in the Qiangtang block. These materials extrude along the JSJS and BNS with both rotation and dispersion in Daguaiwan. Finally, it extends toward southeast direction. (4)There is the crust-mantle transition zone of no distinct velocity jump in the lithosphere beneath the Qiangtang Terrane. It has thinner lithosphere and developed thicker asthenosphere. It implies that the crust-mantle transition zone of partial melting is connected with the developed asthenosphere. The underplating of asthenosphere may thin the lithosphere. This buoyancy might be the main mechanism and deep dynamics of the uplift of the Qinghai-Tibet hinterland. At the same time, the transport of hot material with low velocity intrudes into the upper mantle and the lower crust along cracks and faults forming the crust-mantle transition zone.