近太湖新银鱼——银鱼移植新对象

近太湖新银鱼不仅在形态上与太湖新银鱼很相似,而且它们的个体大小、生长速度、食性等方面也十分相近。近几年在湖北地区的湖泊、水库相继发现了近太湖新银鱼,并在湖北省广水市徐家河水库成为优势种类,形成了较大生产规模。从目前研究的结果来看,近太湖新银鱼也是适宜我国湖泊、水库移植的银鱼种类。     

平面裂隙参数计算及其对浆液流动的影响分析

利用从层流到紊流的多阶段稳定压水试验的压力－流量曲线反算裂隙张开度、粗糙度及地下水影响半径等裂隙参数。建立了平面裂隙中浆液流动的力学模型,并分析了对浆液流动的影响因素。     

合成锂皂石用作钻井液造浆材料实验研究

高温下水基钻井液中膨润土颗粒会发生高温分散或高温聚结作用,从而导致钻井液性能发生剧变,针对这一问题,开展了合成锂皂石用作钻井液造浆材料实验研究。采用X射线粉晶衍射、扫描电镜及红外光谱对合成锂皂石H-6样进行了结构表征,对其分散性、抗盐性及抗温性能等进行了评价,并分析了合成锂皂石抗高温增稠机理。试验结果发现:合成锂皂石H-6样层间存在Na+与Li+两种阳离子,其阳离子交换容量(CEC)为149. 1mmol/100g,而且远高于钠膨润土的CEC值;合成锂皂石极易分散在水中,能明显提高水相的黏度,而且不受水化时间及水化温度影响。例如,当H-6加量从0. 5%增加至4%时,其分散体系的表观黏度从1. 5mPa·s增加至63. 5mPa·s;随着温度增加,合成锂皂石分散体系的表观黏度呈先增加后基本不变趋势,未出现高温明显增稠或高温减稠现象。例如,2%H-6分散体系在180～240℃高温老化后,其表观黏度在22～24mPa·s变化;合成锂皂石H-6样与其它处理剂配伍性好,采用其作为造浆材料配制的超高温水基钻井液具有优良的抗高温稳定性及高温流变性能,无需添加抗高温增黏剂及抗高温稀释剂来调整钻井液的流变性能。研究结果表明,合成锂皂石具有优良的抗高温分散性能,适合用作抗高温造浆材料,用于配制超高温水基钻井液。     

1–100 μm energy spectra and 2.3–4 μm spectrophotometry of MSC stars

The JHKL' photometry and 2.3–4 μm spectrophotometry of some M giants, S type stars and carbon stars are presented in this paper. It is found that in combination with IRAS data, the energy spectra in 1–100 μm of S type stars are intermediate between those of M giants and carbon stars, which are obviously different. The spectrophotometry in the near infrared shows that, besides carbon stars, which have HCN and C₂H₂ strong absorptions at 3.1 μm, some S type stars have the similar but weaker absorption in the same spectral region. However, no trace of any absorption at 3.1 μm can be seen in M giants. These results probably provide more evidence for the M-S-C sequence in the late stage of stellar evolution.     

Analysis on the interplanetary causes of the great magnetic storms in solar maximum (2000-2001)

In this paper, we analyze the interplanetary causes of eight great geomagnetic storms during the solar maximum (2000-2001). The result shows that the interplanetary causes were the intense southward magnetic field and the notable characteristic among the causal mechanism is compression. Six of eight great geomagnetic storms were associated with the compression of southward magnetic field, which can be classified into (1) the compression between ICMEs (2) the compression between ICMEs and interplanetary medium. It suggests that the compressed magnetic field would be more geoeffective. At the same time, we also find that half of all great storms were related to successive halo CMEs, most of which originated from the same active region. The interactions between successive halo CMEs usually can lead to greater geoeffectiveness by enhancing their southward field B_s interval either in the sheath region of the ejecta or within magnetic clouds (MCs). The types of them included: the compression between the fast speed transient flow and the slow speed background flow, the multiple MCs, besides shock compression. Further, the linear fit of the D_st versus gives the weights of and Δt as α=2.51 and β=0.75, respectively. This may suggest that the compression mechanism, with associated intense B_s, rather than duration, is the main factor in causing a great geomagnetic storm.     

The crystal structure of (Fe<Subscript>4</Subscript>Cr<Subscript>4</Subscript>Ni)<Subscript>9</Subscript>C<Subscript>4</Subscript>

(Fe4Cr4Ni)9C4 is a metal carbide mineral formed by combination of Fe, Cr and Ni with C. It occurs in a chromite deposit in the Luobusha ophiolite, Tibet. Based on the determination of its crystal structure, the empirical formula is (Fe4.12Cr3.84Ni0.96)8.92C3.70 and the simplified formula is (Fe4Cr4Ni)4C9. The mineral is hexagonal with a = 1.38392(2) nm, c = 0.44690(9) nm, pace group P63 m c, Z=6 and the calculated specific gravity Dx = 7.089 g/cm3. Fe, Cr and Ni occupy different crystallographic sites and their coordination numbers are approximately 12, forming an alternate stacking sequence of flat and puckered layers along the c axis. Some metallic atoms have a defect structure. The interatomic distances of Fe, Cr and Ni are 0.2525-0.2666 nm, and the distances between Fe, Cr, Ni and C are 0.1893-0.2169 nm. The coordination number of carbon is 6. It occurs in interstices of the metallic atoms Fe, Cr and Ni to form trigonalprismatically coordinated polyhedra. These coordination polyhedra are linked with each other via shared corners or shared edges into a new type of metal carbide structure.     

半参数测量平差模型与系统误差处理

考虑半参数测量模型L=Bx+S+Δ,x$Rd为未知回归参数,S为未知Borel函数。本文首先利用自然样条函数法,找到符合条件的非参数自然插值样条函数。其次利用偏残差法并综合最小二乘法,导出了这种平差方法的解算公式。最后,用一个算例说明了此方法的优越性。     

当前国内酸雨研究进展

回顾了我国在酸雨研究方面所获得的成果,包括酸雨的时空分布特征、影响因素、生态影响模拟以及控制对策等4个方面的内容。大量的研究表明,近些年来酸雨污染的范围有所增加、程度有所加重。酸雨的形成是多种自然和人为因素共同作用的结果,与特定的气象条件、天气类型和大气环流等有密切的关系。针对酸雨污染有所加重的趋势,必须采取有效的控制对策。     

CERES-Wheat模型在我国小麦区的应用效果及误差来源

气候模型与作物模型耦合是评价未来气候变化对作物生产影响的常用方法之一, 但当两者结合时, 存在着空间和时间尺度差异问题, 将作物模型升尺度到区域是解决该差异的一种方法。将CERES-Wheat模型升尺度进行区域模拟, 利用区域校准后的CERES-Wheat模型, 模拟了1981—2000年全国各网格小麦产量, 与同期农调队调查产量相比较, 以探讨CERES-Wheat模型在我国小麦区的模拟效果及误差来源。结果表明:全国小麦产量的区域模拟值与农调队调查产量的相对均方根误差为27.9%, 符合度为0.75, 全国59.2%的模拟网格相对均方根误差在30%以内, 其中相对均方根误差小于15%的占26.3%;各区的效果不同, 种植面积最大的小麦种植生态2区, 模拟效果最好。总体来说, CERES-Wheat的区域模拟, 可以反映产量变化规律, 能为宏观决策提供相应信息, 尤其是在主产区; 但区域模拟中还存在一系列误差, 今后还需进一步研究。