两种不同穗型水稻品种灌浆期间物质生产特性的比较

选用直立穗型水稻品种辽粳 32 6和弯曲穗品种奥羽 316 ,在相同栽培条件下 ,比较两品种灌浆期间物质生产与分配、群体生长率 (CGR)、净同化率 (NAR)及与物质生产密切相关的叶绿素含量、叶面积指数 (LAl)、比叶重等指标。结果表明 ,和弯曲穗品种奥羽 316相比 ,直立穗品种辽粳 32 6在灌浆后期仍能保持较强的物质生产能力 ,其抽穗后生产的干物质量占其生物产量的 5 3.77% ,比其经济产量高出 12 %。灌浆期间 ,直立穗品种辽粳 32 6的比叶重较高 ,叶绿素含量较高 ,LAI下降较慢 ,各项生理指标优于弯曲穗品种奥羽 316。抽穗后 ,直立穗品种辽粳 32 6具有比弯曲穗品种奥羽 316更强的生产能力 ,因而更符合高产栽培的需要。

杉木林林下植被凋落物对土壤动物群落的影响

为了解林下植被对土壤环境的相对影响,对人工杉木纯林凋落物和含有林下植被凋落物的杉木林进行取样调查。结果:共获得土壤动物9 316只,隶属21个目。旱生优势种为蜱螨目和弹尾目,湿生优势种为线蚓和线虫。杉木林区林下植被对土壤动物的影响不依赖于凋落物的现存量,而取决于凋落物质量。

水稻生育后期生化特性分析

以2个不同穗型品种辽粳326(直立型)和奥羽316(弯穗型)为试材,测定了水稻生育后期生理生化指标,每次取倒2叶进行测定,包括超氧化物歧化酶(SOD)、过氧化物酶(POX)、过氧化氢酶(CAT)和可溶性蛋白质含量。从测定结果来看,抽穗前辽粳326各项指标明显高于奥羽316,抽穗以后各项指标变化有所不同,体现了两品种不同的衰老特性。

物候学研究进展及中国现代物候学面临的挑战

文章回顾了中国现代物候学的创立和发展历程,综述了现代物候学的最新研究进展。现代物候学在全球变化研究中发挥了巨大作用;物候学是全球生态学和陆地生态系统碳循环研究的新线索;现代物候研究中,新技术发挥了巨大作用,自动监测技术的引入使物候观测数据的获取方式取得较大进展;此外,传统物候观测继续受到重视,但研究对象更精致、细微,逐渐向微观方向发展。与国际物候学的迅猛发展相比,我国的物候研究遇到空前挑战。因此,中国的物候学研究者任重道远,许多基础性工作有待于深入开展。

东亚土地覆盖对ENSO事件的响应特征

对1982—1993年气候年际变化的强信号———ENSO进行了确认及再分类。以美国地质调查局EROS中心提供的AVHRR8kmNDVI为数据源,应用地理信息系统技术,计算了1982—1993年每年夏季(5—9月)NDVI平均影像。在此基础上用数据断面分析法对ENSO年东亚地区土地覆盖的空间分布进行了分析,再用主成分分析法对同一时间序列NDVI平均影像进行了运算,发现其第7主成分影像所反映的土地覆盖分布与数据断面分析法所反映的结果是一致的。对此,进一步分析了第7主成分的特征向量与代表ENSO变化特征的南方涛动指数(SOI)之间的关系,进而,对ENSO驱动下的东亚地区土地覆盖年际变化的空间分布特征进行了总结。

Synthesis, photoluminescence, thermoluminescence and dosimetry properties of novel phosphor KSr4(BO3)(3):Ce

Polycrystalline powder sample of KSr4(BO3)(3) was synthesized by high-temperature solid-state reaction. The influence of different rare earth dopants, i.e. Tb3+, TM3+ and Ce3+, on thermoluminescence (TL) of KSr4(BO3)(3) Phosphor was discussed. The TL, photoluminescence (PL) and some dosimetric properties of Ce3+-activated KSr4(BO3)(3) phosphor were studied. The effect of the concentration of Ce3+ on TL intensity was investigated and the result showed that the optimum Ce3+ concentration was 0.2 mol%. The TL kinetic parameters of KSr4(BO3)(3):0.002 Ce3+ phosphor were calculated by computer glow curve deconvolution (CGCD) method. Characteristic emission peaking at about 407 and 383 nm due to the 4f(0)5d(1) -> F-2((5/2),(7/2)) transitions of Ce3+ ion were observed both in PL and three-dimensional (3D) TL spectra. The dose-response of KSr4(BO3)(3):0.002 Ce3+ to gamma-ray was linear in the range from 1 to 1000 mGy. In addition, the decay of the TL intensity of KSr4(BO3)(3):0.002 Ce3+ was also investigated.

用过渡金属络合催化剂在水介质中引发烯烃单体的配位聚合

介绍了乙烯、丁二烯和苯乙烯等单体在水介质中用过渡金属络合催化剂合成有规立构聚合物 的研究进展,详细阐述了钴系催化剂在水介质中合成间同1, 2 - 聚丁二烯的研究成果。

Thermal annealing of Au nanorod self-assembled nanostructured materials: Morphology and optical properties

Three-dimensional Au nanorod and An nanoparticle nanostructured materials were prepared by layer-by-layer self-assembly. The plasmonic properties of the An nanorod and An nanoparticle self-assembled nanostructured materials (abbreviated as AuNR and AuNP SANMs) are tunable by the controlled self-assenibly process. The effect of thermal annealing at 180 and 500 degrees C to the morphologies, plasmonic properties and surface-enhanced Raman scattering (SERS) responses of these SANMs were investigated. According to the experimental results, these properties correlate with the structure of the SANMs.

Preparation and transport properties of a bulk icosahedral quasicrystalline Ti45Zr35Ni17Cu3 alloy

A bulk alloy which consists of the single icosahedral quasicrystalline phase (I-phase) in Ti45Zr35Ni17CU3 alloy has been fabricated by mechanical alloying and subsequent pulse discharge sintering technique. Crystallographic structure analyses show that the bulk alloy is an I-phase. The transport properties of the bulk alloy are examined, and the results show that the room-temperature thermal conductivity is 5.347 W K-(1) m(-1), and the electrical conductivity decreases with increasing the temperature from 300 to 450K. The Seebeck coefficient is negative at the temperature range from 300 to 360K, and changes to positive from 370 to 450K. Hall effect measurements indicate the bulk I-phase alloy has a high carrier concentration. The specific heat capacity increases when the temperature increases from 280 to 324 K.

High gain in hybrid transistors with vanadium oxide/tris(8-hydroxyquinoline) aluminum emitter

We report the electrical characterization of hybrid permeable-base transistors with tris(8-hydroxyquinoline) aluminum as emitter layer. These transistors were constructed presenting an Al/n-Si/Au/Alq(3)/V2O5/Al structure. We investigate the influence of the V2O5 layer thickness and demonstrate that these devices present high common-base and common-emitter current gain, and can be operated at very low driving voltages, lower than 1 V, in both, common-base and common-emitter modes.

Selective hydrogenation of citral with transition metal complexes in supercritical carbon dioxide

The activity and selectivity of the transition metal complexes formed from Ru, Rh, Pd and Ni with triphenylphosphine (TPP) have been investigated for hydrogenation of citral in supercritical carbon dioxide (scCO(2)). High activities are obtained with Ru/TPP and Pd/TPP catalysts, and the overall activity is in the order of Pd approximate to Ru > Rh > Ni. The Ru/TPP complex is highly selective to the formation of unsaturated alcohols of geraniol and nerol. In contrast, the Pd/TPP catalyst is more selective to partially saturated aldehydes of citronellal. Furthermore, the influence of several parameters such as CO2 and H-2 pressures, N-2 pressure and reaction time has been discussed. CO2 pressure has a significant impact on the product distribution, and the selectivity for geraniol and nerol can be enhanced from 27% to 75% with increasing CO2 pressure from 6 to 16 MPa, while the selectivity for citronellol decreases from 70% to 20%. Striking changes in the conversion and product distribution in scCO(2) could be interpreted with variations in the phase behavior and the molecular interaction between CO2 and the substrate in the gas phase and in the liquid phase.

Study on the instability of organic field-effect transistors based on fluorinated copper phthalocyanine

The effects of positive and negative gate-bias stress on organic field-effect transistors (OFET) based on tantalum (Ta)/tantalum pentoxide (Ta2O5)/fluorinated copper phthalocyanine (F16CuPc) structure are investigated as a function of stress time and stress temperature. It is shown that gate-bias stress induces a parallel threshold voltage shift (DeltaV(T)) of OFETs without changes of field-effect mobility mu(EF) and sub-threshold slope (DeltaS). The DeltaV(T) is observed to be logarithmically dependent on time at high gate-bias appropriate to OFET operation. More importantly, the shift is directional, namely, be large shift under positive stress and almost do not move under negative stress. The threshold voltage shift is temperature dependent with activation energy of 0.51 eV We concluded that threshold voltage shift of the OFET with F16CuPc as active layer is due to charge trapping in the insulator in which trapped carriers have redistribution.