GRAPES模式在一次近海强风预报中的应用

利用GRAPES模式和广东自动站资料,从天气学的角度对比、分析研究了GRAPES模式预告在2010年12月15—17日广东出现强冷空气天气过程中上川岛附近海域强风的对应关系。结果表明,在此次近海强风的过程中,GRAPES模式的预报能力及其提前量,在实际冷空气海洋强风预报业务中值得参考,模式气压场的预报与实况没有明显的差异,强度基本一致,模式区域风向风速预报与实况较为吻合,模式单点预报能提前量为60 h报出风向风速的突变,并且时间误差在3 h左右,模式提前量达60 h以上。     

Certification of ERM‐EB400, the First Matrix Reference Material for Lead Isotope Amount Ratios,and ERM‐AE142, a Lead Solution Providing a Lead Isotopic Composition at the Edge of Natural Variation

Lead isotope amount ratios are commonly used in diverse fields such as archaeometry, geochemistry and forensic science. Currently, five reference materials with certified lead isotope amount ratios are available, namely NIST SRM 981, 982 and 983, GBW‐04442 and NMIJ 3681‐a. Only NIST SRM 981 and NMIJ 3681‐a have approximately natural isotopic compositions, and NIST SRM 981 is predominantly used for correcting mass discrimination/mass fractionation in the applied mass spectrometric procedures. Consequently, there is no other certified reference material available to be used for validation and/or quality control of the analytical procedures applied to lead isotope amount ratio measurements. To fill this gap, two new reference materials have been produced and certified for their lead isotope amount ratios. For both certified reference materials, complete uncertainty budgets have been calculated and SI traceability has been established. This provides the users with independent means for validating and verifying their analytical procedures and for conducting quality control measures. ERM‐EB400 is a bronze material with a nominal lead mass fraction of 45 mg kg^?1 and certified lead isotope amount ratios of n(²⁰⁶Pb)/n(²⁰⁴Pb) = 18.072(17) mol mol^?1, n(²⁰⁷Pb)/n(²⁰⁴Pb) = 15.578(18) mol mol^?1 and n(²⁰⁸Pb)/n(²⁰⁴Pb) = 38.075(46) mol mol^?1 with the associated expanded uncertainties (k = 2) given in brackets. ERM‐AE142 is a high‐purity solution of lead in 2% nitric acid with a nominal mass fraction of 100 mg kg^?1 and certified Pb isotope amount ratios of n(²⁰⁶Pb)/n(²⁰⁴Pb) = 21.114(17) mol mol^?1, n(²⁰⁷Pb)/n(²⁰⁴Pb) = 15.944(17) mol mol^?1 and n(²⁰⁸Pb)/n(²⁰⁴Pb) = 39.850(44) mol mol^?1 with the associated expanded uncertainties (k = 2) given in brackets. Both materials are specifically designed to fall within the natural lead isotopic variation and to assist users with the validation and verification of their analytical procedures. Note that while one of these reference materials requires the chemical separation of Pb from its matrix (ERM‐EB400), the other does not (ERM‐AE142). As additional information, δ^208/206Pb_{NIST SRM981} values are provided for both materials. For ERM‐AE142, a delta value of δ^208/206Pb_{NIST SRM981} = ?28.21(30)‰ was obtained, and for ERM‐EB400, a delta value of δ^208/206Pb_NIST SRM981= ?129.47(38)‰ was obtained, with the associated expanded uncertainties (k = 2) given in brackets.     

西藏则学地区热液脉型铅锌矿S、Pb同位素组成及其对成矿物质来源的启示

德新和轧轧龙铅锌矿是冈底斯西段银铅锌多金属成矿带典型的热液脉型铅锌矿床,关于其成矿物质来源及与纳如松多铅锌矿成因联系的研究鲜有开展。本研究利用单矿物和全岩稳定同位素方法对德新和轧轧龙铅锌矿的主要金属硫化物和含矿花岗斑岩进行了S、Pb同位素组成分析和示踪,结果显示德新铅锌矿硫化物δ34SVCDT为3.5‰～7.4‰,平均值为6.1‰;含矿花岗斑岩δ334SVCDT为4.4‰～6.2‰,平均值为5.7‰;轧轧龙铅锌矿金属硫化物δ334SVCDT为2.7‰～8.3‰,平均值为5.1‰;德新和轧轧龙铅锌矿铅同位素比值比较稳定,变化范围基本一致;铅同位素μ值为9.48～9.82,平均值为9.64;△β、△γ变化范围基本一致,均值相差较小,表明则学地区热液脉型铅锌矿金属硫化物和斑岩具有一致的S、Pb同位素组成,铅同位素具正常铅特征;暗示硫源可能主要由花岗岩类提供,铅源则可能主要来自上地壳物质。综合前人研究认为,德新、轧轧龙热液脉型铅锌矿和纳如松多铅锌矿具有一致的硫、铅同位素组成,三者应存在成因上的联系,可能属于同一成矿系统产物;花岗斑岩为则学地区热液脉状铅锌矿化提供了成矿物质。     

青海玛温根矿区氧化铅银矿工艺矿物学特性及分析研究

结合光学显微镜鉴定、扫描电镜、X射线能谱探针、筛析等技术手段,系统研究了青海省玛温根矿区产出的有代表性的氧化铅矿石的工艺矿物学特征。结果表明:矿石主要有价元素是Pb(2. 76%)和Ag(204. 4×10-6);矿石中铅的赋存状态较复杂,主要赋存于铅铁矾等难溶铅中,其次赋存于氧化铅、硫酸铅中,矿石中的铅矿物主要是铅矾、白铅矿、砷铅铁矾,少量方铅矿、砷铅矿等;银的赋存状态亦较为复杂,独立银矿物为硫铜银矿,含量甚微,部分银呈类质同像赋存于其他的金属硫化物中。通过偏光显微镜和扫描电镜分析发现,主要的铅矿物如铅矾、白铅矿等相互交代连生现象明显,且嵌布粒度细小,这与筛析检测结果相一致,同时矿石中As含量较高,达到了5. 43%,含砷矿物主要为毒砂、臭葱石,经X射线能谱分析,部分铅矿物与砷元素关系密切,并形成了砷铅铁矾、砷铅矿等复杂砷铅矿物。所以预测在选矿过程中,砷会随铅矿物同步富集,银的独立银矿物主要是硫铜银矿,且嵌布粒度微细,大部分银矿物以微细粒包裹态赋存于石英、褐铁矿等硅酸盐或氧化物中。根据以上研究成果,可判定该氧化铅银矿属于极难选矿石,建议采用浮选-化学选矿工艺综合回收铅、银金属的技术路线。     

Modeling cyclic loading behavior of jointed precast concrete connections including effects of friction,tendon yielding and dampers

Reversed cyclic loading behavior of jointed precast prestressed concrete beam‐to‐column connections are computationally modeled and validated against full‐scale experimental results. Response simulations are performed with and without supplemental high force‐to‐volume (HF2V) energy dissipation devices. The experimental specimen is a three‐dimensional corner connection of a jointed precast concrete frame structure, utilizing unbonded post‐tensioned tendons consisting of high‐alloy, high‐strength thread‐bars. The joint region is armored, to avoid damage, by providing steel plates at the beam–column (rocking) contact points. The analytical model of the connection is developed to include modifications for the effects of changing connection behavior. These effects are friction within the prestressing system, yielding of the prestressing tendons, reduction or elimination of prestress attributable to prior tendon yield, and directional dependence caused by an asymmetrical prestress system. Particular attention is given to developing a robust model that can accommodate small reversals in the displacement loading. The model is extended to incorporate the effects of the HF2V energy dissipation devices and the associated flexibility from the elements that connect the devices to the structure. Although the model is applied to the use of HF2V (lead extrusion) energy dissipation devices, it is general and can accommodate any non‐linear rate‐dependent damper. The computational model is based almost entirely on rational mechanics and shows good agreement with the full‐scale experimental observations. Copyright © 2012 John Wiley & Sons, Ltd.     

Lead in blood and eggs of the sea turtle, Lepidochelys olivacea, from the Eastern Pacific: Concentration, isotopic composition and maternal transfer

Concentrations of lead were assessed in the sea turtle, Lepidochelys olivacea, from a nesting colony of the Eastern Pacific. Twenty-five female turtles were sampled and a total of 250 eggs were collected during the “arribada” event of the 2005-2006 season. Considering the nesting season, the maternal transfer of lead (Pb) via egg-laying, in terms of metal burden in whole body, was 0.5%. Pb concentrations (in dry weight) in blood (0.95 ± 0.18 μg g⁻¹) and egg samples (yolk, 0.80 ± 0.10 μg g⁻¹; albumen, 1.08 ± 0.20 μg g⁻¹; eggshell, 1.05 ± 0.20 μg g⁻¹) were comparable or even lower than those found in other sea turtles. The isotope ratios (²⁰⁶Pb/²⁰⁷Pb and ²⁰⁶Pb/²⁰⁸Pb) in blood (1.183 ± 0.0006 and 2.452 ± 0.0006, respectively) were comparable to that of natural Pb-bearing bedrock in Mexico (1.188 ± 0.005 and 2.455 ± 0.008, respectively). According to international norms of Pb, the health of this population and its habitats is acceptable for Pb and corresponds to basic levels of a nearly pristine environment.     

西藏当雄县拉屋铜铅锌多金属矿床喷流沉积成因

拉屋铜铅锌多金属矿床位于纳木错-嘉黎断裂带南侧的上石炭统-下二叠统来姑组中,矿体分布受日音拿背斜控制。矿区内矿化类型以层纹状、层状矿化为主,晚期有脉状矿化叠加。在矿床地质特征研究基础上,通过矿石和容矿围岩的稀土元素、稳定同位素地球化学特征分析,探讨了成矿物质来源及矿床成因。研究显示,矿床容矿围岩稀土元素具有弱Ce负异常（0.89～0.95）和Eu中等亏损（0.56～0.64）的特点。硫化物硫同位素δ³⁴S值变化范围为-2.92‰～-0.42‰,平均值为-1.68‰,为深源硫来源。矿石中石英包裹体氢氧同位素组成显示,矿床成矿热液流体早期以深循环的海水与岩浆水的混合流体为主,中、晚期则有为长时间大气降水的参与,成矿流体来源以大气降水为主。综合研究表明:拉屋铜铅锌多金属矿床属于喷流沉积-叠加改造型矿床,具有喷流沉积型矿床的特征,燕山期则表现为岩浆热液活动叠加改造。     

粤北仙石铀矿床的铅、碳、硫同位素研究

仙石铀矿床位于粤北贵东复式花岗岩体东部,矿体赋存于NWW向辉绿岩与NEE向硅化带交接部位。矿床中黄铁矿以富集放射成因铀铅为特征,3组比值分别为(^208Pb／^304Pb)．=18．756—23．883,(^207Pb／^304Pb)1=15．676～15．932,(^208Pb／^204Pb),=38．530—38．938,主要位于基底变质岩铅范围内;矿床中方解石δ^18C值为-8．5‰～-3．1‰,相似于地幔值((-5±2)‰);黄铁矿δ^18C值为-10．1‰～-8．3‰,它与花岗岩中黄铁矿δ^18C值(-10．9‰--7．1‰)相似,而与辉绿岩中黄铁矿δ^18C值(-0．03‰～2．1‰)区别明显。上述同位素特征表明仙石铀矿床的成矿物质具多源特征。     

西藏新嘎果铅锌矿床矽卡岩矿物及金属矿物特征

新嘎果矿床是西藏冈底斯成矿带北缘矽卡岩多金属成矿带的一个典型矽卡岩型铅锌矿床。矽卡岩矿体主要呈层状、似层状产于下白垩统塔克那组地层中。电子探针测试结果表明,矽卡岩矿物主要为钙铝榴石、钙铁辉石和绿帘石,少量的硅灰石、密绿泥石等,构成典型的钙质矽卡岩。金属矿物主要为闪锌矿、方铅矿、磁黄铁矿、黄铜矿、黄铁矿,少量的白铁矿、毒砂、自然铋、斜方辉铅铋矿、辉砷镍矿等。该矿床中石榴子石成分特征指示成矿环境是变化的,在早期进变质阶段由氧化环境向还原环境转变,而晚期退变质阶段由氧化环境向还原环境转变。金属矿物中闪锌矿主要为铁闪锌矿,表明其形成于中高温环境。而含铋的矿物主要为自然铋、斜方辉铅铋矿和方铅矿,并且在这些矿物中Ag和Bi的含量呈正相关性,指示铋对银的富集可能起着重要的作用;此外,铋也是新嘎果矿床重要的伴生有用元素,具有较高的综合利用价值。     

地铁施工精准测控技术研究

地铁测量是地铁建设工程的一个重要组成部分,为使地铁测量更好地服务于地铁工程建设,确保地铁施工的高质量和高安全度,在实践的基础上提出了地铁施工精准测控的思想,给出了地铁测量的基本原则和合理技术要求,介绍了地铁施工精准测控的技术关键,叙述了竖井高精度联系测量的作业方法,在地铁测量的高精度与高效率问题上进行了有益的探索。