92Nb-(92)Zr and the Early Differentiation History of Planetary Bodies

The niobium-92-zirconium-92 ((92)Nb-(92)Zr) extinct radioactive decay system (half-life of about 36 million years) can place new time constraints on early differentiation processes in the silicate portion of planets and meteorites. Zirconium isotope data show that Earth and the oldest lunar crust have the same relative abundances of (92)Zr as chondrites. (92)Zr deficits in calcium-aluminum-rich inclusions from the Allende meteorite constrain the minimum value for the initial (92)Nb/(93)Nb ratio of the solar system to 0.001. The absence of (92)Zr anomalies in terrestrial and lunar samples indicates that large silicate reservoirs on Earth and the moon (such as a magma ocean residue, a depleted mantle, or a crust) formed more than 50 million years after the oldest meteorites formed.     

Supra-canonical 26Al/27Al and the residence time of CAIs in the solar protoplanetary disk

The canonical initial 26Al/27Al ratio of 4.5 x 10(-5) has been a fiducial marker for the beginning of the solar system. Laser ablation and whole-rock multiple-collector inductively coupled plasma-source mass spectrometry magnesium isotope analyses of calcium- and aluminum-rich inclusions (CAIs) from CV3 meteorites demonstrate that some CAIs had initial 26Al/27Al values at least 25% greater than canonical and that the canonical initial 26Al/27Al cannot mark the beginning of solar system formation. Using rates of Mg diffusion in minerals, we find that the canonical initial 26Al/27Al is instead the culmination of thousands of brief high-temperature events incurred by CAIs during a 10(5)-year residence time in the solar protoplanetary disk.     

Type II Supernova Matter in a Silicon Carbide Grain from the Murchison Meteorite

The circumstellar silicon carbide (SiC) grain X57 from the Murchison meteorite contains large amounts of radiogenic calcium-44 (20 times its solar system abundance) and has an anomalous silicon isotopic composition, different from other circumstellar SiC grains. Its inferred initial 44Ti/Si and 44Ti/48Ti ratios are 1.6 x 10(-4) and 0.37. In addition, it contains radiogenic magnesium-26; the inferred initial 26Al/27Al ratio is 0.11. The isotopic and elemental data of X57 can be explained by selective mixing of matter from different zones of a typical type II supernova of 25 solar masses during its explosion. The high 44Ti/Si ratio requires contributions from the innermost nickel zone of the supernova to the SiC condensation site, as similarly suggested by astronomical observations.     

Evidence for Widespread 26Al in the Solar Nebula and Constraints for Nebula Time Scales

A search was made for 26Mg (26Mg*) from the decay of 26Al (half-life = 0.73 million years) in Al-rich objects from unequilibrated ordinary chondrites. Two Ca-Al-rich inclusions (CAIs) and two Al-rich chondrules (not CAIs) were found that contained 26Al when they formed. Internal isochrons for the CAIs yielded an initial 26Al/27Al ratio [(26Al/27Al)0] of 5 x 10(-5), indistinguishable from most CAIs in carbonaceous chondrites. This result shows that CAIs with this level of 26Al are present throughout the classes of chondrites and strengthens the notion that 26Al was widespread in the early solar system. The two Al-rich chondrules have lower 26Mg*, corresponding to a (26Al/27Al)0 ratio of approximately 9 x 10(-6). Five other Al-rich chondrules contain no resolvable 26Mg*. If chondrules and CAIs formed from an isotopically homogeneous reservoir, then the chondrules with 26Al must have formed or been last altered approximately2 million years after CAIs formed; the 26Mg*-free chondrules formed >1 to 3 million years later still. Because 26Mg*-containing and 26Mg*-free chondrules are both found in Chainpur, which was not heated to more than approximately400°C, it follows that parent body metamorphism cannot explain the absence of 26Mg* in some of these chondrules. Rather, its absence indicates that the lifetime of the solar nebula over which CAIs and chondrules formed extended over approximately5 million years.     

F小体检测奶牛XY精子纯度

为了建立F小体检测奶牛精子纯度的方法,试验采用正交设计检测精子F小体不同的胰酶消化时间（40min,60min,80min）、喹吖因染色浓度（0．4％,0．5％,0．6％）和染色时间（10min,20min,30min）的优化方案,并且对分选X、Y精子及常规精液的F小体进行染色检测,评价分选X、Y精子的纯度。结果显示分选x、Y精子及常规精液在0．25％胰酶消化20min后0．5％喹吖因染色10min的条件下,纯度分别为92．7％、92．5％、48．3％与对应精子的理论纯度（93．3％,93．7％,50％）差异均不显著（P〉0．05）。因此本实验建立的F小体检测法可用于XY精子纯度的检测。     

A 15N-poor isotopic composition for the solar system as shown by Genesis solar wind samples

The Genesis mission sampled solar wind ions to document the elemental and isotopic compositions of the Sun and, by inference, of the protosolar nebula. Nitrogen was a key target element because the extent and origin of its isotopic variations in solar system materials remain unknown. Isotopic analysis of a Genesis Solar Wind Concentrator target material shows that implanted solar wind nitrogen has a (15)N/(14)N ratio of 2.18 ± 0.02 × 10(-3) (that is, ≈40% poorer in (15)N relative to terrestrial atmosphere). The (15)N/(14)N ratio of the protosolar nebula was 2.27 ± 0.03 × 10(-3), which is the lowest (15)N/(14)N ratio known for solar system objects. This result demonstrates the extreme nitrogen isotopic heterogeneity of the nascent solar system and accounts for the (15)N-depleted components observed in solar system reservoirs.     

Deuterated methane observed on saturn

Absorptions for the V(2) band of deuterated methane (CH(3)D) have been observed in the 5-micron spectrum of Saturn, obtained with a Fourier transform spectrometer. Analysis of the band yields a CH(3)D abundance of 2.6 +/- 0.8 centimeter-amagat and a temperature of 175 +/- 30 K for the mean level of spectroscopic line formation. This temperature indicates that a substantial portion of Saturn's flux at 5 microns is due to thermal radiation, and that we are therefore looking fairly deep into its atmosphere, as is the case for the Jupiter 5-micron window. This CH(3)D abundance leads to a deuteriumlhydrogen ratio of about 2 x 10(-5) in Saturn's atmosphere. This ratio is much lower than the terrestrial value but comparable to that determined for Jupiter and may be taken as representative of the deuteriumlhydrogen ratio in the solar system at the time of its formation.     

Extinct (129)I in halite from a primitive meteorite: evidence for evaporite formation in the early solar system

Halite crystals from the Zag H3-6 chondrite contain essentially pure (monoisotopic) xenon-129 ((129)Xe) produced in the early history of the solar system by the decay of short-lived iodine-129 ((129)I) (half-life = 15.7 million years). Correlated release of (129)Xe and (128)Xe, produced artificially from (127)I by neutron irradiation, corresponds to an initial ((129)I/(127)I) ratio of (1.35 +/- 0.05) x 10(-4), close to the most primitive early solar system value. If the (129)Xe was produced by in situ decay, then the halite formed from an aqueous fluid within 2 million years of the oldest known solar system minerals.     

小麦新品种R_(59)成熟胚的组织培养初报

选配 3种培养基 ,以小麦新品种R59的成熟胚作外植体进行组织培养。结果显示 :不同培养基中的成愈情况差异较大 ,其中培养基Ms +2 ,4 -D2 0mg/l+KT0 5mg/L的效果较好 ,成愈率高达 92 %～ 93 3%。结果同时表明 :胚芽对形成胚性愈伤组织不利     

Chondrite barium, neodymium, and samarium isotopic heterogeneity and early Earth differentiation

Isotopic variability in barium, neodymium, and samarium in carbonaceous chondrites reflects the distinct stellar nucleosynthetic contributions to the early solar system. We used 148Nd/144Nd to correct for the observed s-process deficiency, which produced a chondrite 146Sm-142Nd isochron consistent with previous estimates of the initial solar system abundance of 146Sm and a 142Nd/144Nd at average chondrite Sm/Nd ratio that is lower than that measured in terrestrial rocks by 21 +/- 3 parts per million. This result strengthens the conclusion that the deficiency in 142Nd in chondrites relative to terrestrial rocks reflects 146Sm decayand earlyplanetary differentiation processes.     

Escape of hydrogen from venus

Recombination of O(2)(+) represents a source of fast oxygen atoms in Venus' exosphere, and subsequent collisions of oxygen atoms with hydrogen atoms lead to escape of about 10(7) hydrogen atoms per square centimeter per second. Escape of deuterium atoms is negligible, and the ratio of deuterium to hydrogen should increase with time. It is suggested that the mass-2 ion observed by Pioneer Venus is D(+), which implies a ratio of deuterium to hydrogen in the contemporary atmosphere of about 10(-2), an initial ratio of 5 x 10(-5) and an original H(2)O abundance not less than 800 grams per square centimeter.     

Zodiacal dust and deep-sea sediments

The recent detection of radioactive Al(26) in marine sediments has led to the conclusion that it is brought into the earth's atmosphere by micrometeorites which have been exposed, in interplanetary space, to solar high-energy protons. The Al(26) method is not precise enough to yield directly a reliable value for the mass accretion rate to the earth to better than about 3 orders of magnitude, but is sufficiently accurate to allow a crucial decision between two widely differing of interplanetary dust which have been proposed to explain observations of the zodiacal light. The two models lead to Al(26) concentrations which would differ by about 5 orders of magnitude. Thus, the presence of Al(26) is consistent with the zodiacal dust model with particles of some tens of microns rather then with submicron particles. From this model a mass accretion to the earth then be calculated which is set at 1250 (upper limit, 2500; lower limit, 250) tons per day, or 2.8 x 10(-15) g/cm(2) sec, or 4.5 x 10(11) g over the earth per This value does not depend on the flux of the solar high-energy particles, which may be uncertain by an order of magnitude or more. The presence of Al(26) supports the idea that an important fraction of the dust is stony in composition material density, and thus eliminates some more exotic dust models, as such one consisting entirely of carbon grains. We may also conclude that the accreted dust particles have been in the solar system and exposed to protons from solar high-energy particles for a time interval which is greater than a significant of the Al(26) half-life (0.74 x 10(6) years).     

一个水稻落粒性基因SH1的SSR标记定位

 以籼稻品种93-11为轮回亲本,与粳稻品种日本晴杂交并回交的高世代分离群体为研究材料,选用104个多态性的SSR标记对水稻的落粒性基因进行定位。结果表明,在BC₄F₂群体中,6个标记的基因型来自于日本晴;在BC₄F₃定位群体中,难落粒植株数与易落粒植株数的分离比例为3:1,落粒性受1对显性基因控制,命名为SH1;分子标记与落粒性共分离分析将SH1定位在SSR标记RM5389和RM1068、RM1387之间,与3个标记的遗传距离分别为0.7cM、5.5cM和13.1cM,此结果为该基因的分子标记辅助选择奠定了基础。     

The polar ionosphere of venus near the terminator from early pioneer venus orbiter radio occultations

Fourteen profiles of electron density in the ionosphere of Venus were obtainecd by the dual-frequency radio occulation method with the Pioneer Venus orbiter between 5 and 30 December 1978. The solar zenith angles for these measurements were between about 85 degrees and 92 degrees , and the latitudes ranged from about 81 degrees to 88 degrees (ecliptic north). In addition to the expected decreasein peak electron density from about 1.5 x 10(3) to 0.5 x 10(3) per cubic centimeter with increasing solar zenith angle, a region of almost constant electron density above about 250 kilometers was observed. The ionopause height varies from about 300 to 700 kilometers and seems to be influenced by diurnal changes in solar wind conditions. The structures of the profiles are consistent with models in which O(2)(+) dominates near the ionization peak and is replaced by O(+) at higher altitudes.     

石家庄地区地源热泵与太阳能复合空调系统的应用研究

针对我国北方地区地源热泵空调系统普遍存在的热平衡失调问题,设计了一款地源热泵与太阳能复合空气调节系统,并于2010年在石家庄市的老年公寓工程改造中应用。结果表明该系统效果良好,改造后比改造前地埋管换热器初始出水温度提高6℃;最低出水温度提高5℃;地源热泵机组能效比由1.67提高到3.82;冬季运行费用由20元/m2降低至11元/m2;该工程冬季总运行费用由5万元降低至2.75万元。该实例证明该系统结合了地源热泵和太阳能的各自优点,在石家庄地区应用效果明显,并且用于太阳能系统的初投资4.5万元一年后已收回成本,有推广应用的价值。     

4%高氯·甲维盐微乳剂防治甜菜夜蛾田间药效试验研究

[目的]明确4%高氯.甲维盐微乳剂对甜菜夜蛾的田间防治效果。[方法]在苞菜田中,于甜菜夜蛾发生初期,按照不同施药量兑水进行叶面喷雾,计算各处理防效。[结果]该药剂有效成分用量21~27 g/hm2,药后2 d防效为91%~99%,药后5 d防效为92%~99%,药后10天防效为92%~98%,显著优于对照药剂4.5%高效氯氰菊酯乳油和1%甲氨基阿维菌素苯甲酸盐乳油。[结论]该药剂速效性好,持效性显著,可作为防治十字花科蔬菜甜菜夜蛾的有效药剂和替代乳油的环保剂型进行推广使用,推荐用药量为有效成分用量24~27 g/hm2。     

江西省农业生态经济系统能值分析

应用H．T．Odumd岫的能值分析理论方法,对江西省农业生态经济系统的能值流进行了分析。结果表明,2005年能值投入量为4．46×10^22sej,能值产出量为6．21×10^22sej,净能值产出率为1．00,环境负载率为0．61,可持续发展指数为1．63。江西农业处于传统农业向现代农业转变的转型期。为了促进江西农业的可持续发展,应加强系统的能值投入和农业基础设施的建设,增大农业的科学技术研究和推广力度,优化系统的能值投入结构,调整农业产业结构。     

Modelling of maize production in Croatia: present and future climate

Maize is one of the most important agricultural crops in Croatia, and was selected for research of the effect of climate warming on yields. The Decision Support System for the Agrotechnology Transfer model (DSSAT) is one of the most utilized crop-weather models in the world, and was used in this paper for the investigation of maize growth and production in the present and future climate. The impact of present climate on maize yield was studied using DSSAT 4.0 with meteorological data from the Zagreb-Maksimir station covering the period 1949-2004. Pedological, physiological and genetic data from a 1999 field maize experiment at the same location were added. The location is representative of the continental climate in central Croatia. The linear trends of model outputs and the non-parametric Mann-Kendall test indicate that the beginning of silking has advanced significantly by 1·4 days/decade since the mid-1990s, and maturity by 4·5 days/decade. It also shows a decrease in biomass by 122 kg/ha and in maize yield by 216 kg/ha in 10 years.Estimates of the sensitivity of maize growth and yield in future climates were made by changing the initial weather and CO(2) conditions of the DSSAT 4.0 model according to the different climatic scenarios for Croatia at the end of the 21st century. Changed climate suggests increases in global solar radiation, minimal temperature and maximal temperature (×1·07, 2 and 4°C, respectively), but a decrease in the amount of precipitation (×0·92), compared with weather data from the period 1949-2004. The reduction of maize yield was caused by the increase in minimal and maximal temperature and the decrease in precipitation amount, related to the present climate, is 6, 12 and 3%, respectively. A doubling of CO(2) concentration stimulates leaf assimilation, but maize yield is only 1% higher, while global solar radiation growth by 7% increases evapotranspiration by 3%. Simultaneous application of all these climate changes suggested that the maize growth period would shorten by c. 1 month and maize yield would decrease by 9%, with the main reason for maize yield reduction in Croatia being due to extremely warm conditions in the future climate.     

灰色关联度分析和DTOPSIS法在贵州威宁引进苹果综合评价中的应用

【目的】建立苹果品质综合评价模型,筛选品质优良的品种(系),为贵州省威宁县苹果品种结构优化调整提供参考依据。【方法】测定引进贵州省威宁县种植的10个苹果品种(系)(编号Z1~Z10)果实的单果重(T1)、果形指数(T2)、去皮硬度(T3)、可溶性固形物(T4)、可滴定酸(T5)、固酸比(T6)和果实色泽[L*(T7)、a*(T8)、b*(T9)]9项指标,利用灰色关联度分析联合DTOPSIS法对其进行综合评价,建立苹果品质综合评价模型。【结果】10个苹果品种(系)中,单果重、去皮硬度和固酸比指标最小均为Z9(16-112),但其可滴定酸含量最高,为0.60%;单果重、果形指数、去皮硬度、可溶性固形物含量、固酸比和L*值最大分别为Z3(2-14)、Z1(东71-31)、Z5(秦脆)、Z8(8-31)、Z5(秦脆)和Z9(16-112)。9项果实品质指标的权重值排序为可溶性固形物>去皮硬度>固酸比>果形指数>单果重=a*>可滴定酸>L*=b*。灰色关联度分析结果显示,灰色评判值(G_i)排序为:Z5(秦脆)>Z2(南39-66)>Z1(东71-31)>Z4(147)>Z7(39-134)>Z8(8-31)>Z10(92)>Z3(2-14)>Z6(秦蜜)>Z9(16-112)。DTOPSIS法分析结果显示,与理想品种接近度(C_i)排序为:Z5>Z2>Z1>Z10>Z3>Z7>Z4>Z6>Z8>Z9。2种评价方法排名趋势线吻合度较高,在分析过程中均涵盖9项果实品质指标信息,具有可靠的统计学基础,其中C_i值差异大于G_i值差异;通过2种方法的比较建立苹果品质评价预测模型:Y=0.09T1+0.11T2+0.17T3+0.19T4+0.08T5+0.15T6+0.06T7+0.09T8+0.06T9。【结论】DTOPSIS法对苹果品质的综合评价效果较好,通过权重系数建立的评价模型可用于苹果品质的综合评价,灰色关联度分析联合DTOPSIS法评价结果排序前三均为秦脆、南39-66和东71-31,可作为优化项目区苹果品种结构的重点品种(系)。     

脂肪酶催化合成硬脂酸淀粉酯的研究

在无溶剂体系中,用脂肪酶Lipozyme TL IM催化合成硬脂酸大米淀粉酯。考察了初始水活度、温度、时间、底物配比等因素对淀粉酯合成的影响,用水合盐进行了体系水分的调控。确定最适反应条件为控制水活度0.75,酶与淀粉质量比1/10,温度65℃,反应12 h,取代度可达到0.2188,经红外光谱检测,3 000～3 700cm-1的羟基的伸缩振动的特征峰强度变小,说明是淀粉羟基在酯化后被取代所致。