Properties of the <Emphasis Type="Italic">F</Emphasis>2-layer critical frequency median in the nocturnal subauroral ionosphere during low and moderate solar activity

Based on an analysis of data from the European ionospheric stations at subauroral latitudes, it has been found that the main ionospheric trough (MIT) is not characteristic for the monthly median of the F2-layer critical frequency (foF2), at least for low and moderate solar activity. In order to explain this effect, the properties of foF2 in the nocturnal subauroral ionosphere have been additionally studied for low geomagnetic activity, when the MIT localization is known quite reliably. It has been found that at low and moderate solar activity during night hours in winter, the foF2 data from ionospheric stations are often absent in the MIT area. For this reason, a model of the foF2 monthly median, which was constructed from the remaining data of these stations, contains no MIT or a very weakly pronounced MIT.     

新疆耕地变化对区域碳平衡的影响

基于“Bookkeeping”模型,对1975-2005 年期间新疆耕地变化对区域碳平衡的影响进行了分析。荒漠土地开垦和耕地转移是新疆耕地变化的两种主要方式,1975-2005 年这两种耕地变化方式使新疆碳储量增加了20.6 Tg C,其中土地开垦使区域碳储量增加了51.8 Tg C,而耕地转移则向大气排放了31.2 Tg C。在1975-1985 年期间,新疆耕地大规模转移,区域碳储量的变化趋势受耕地转移的影响较大;1985 年后随新疆土地开垦规模的增加,碳储量变化趋势主要受土地开垦影响。30 年间,新疆碳储量增加主要是由草地开垦为耕地引起,而耕地转移为草地是新疆碳储量减少的主要原因。新疆地区进行合理的水土开发活动有利于区域碳固定,且长期的耕作管理活动会进一步增强耕地的碳汇功能。     

Anomalous variations in the structure of the ionospheric <Emphasis Type="Italic">F</Emphasis><Subscript>2</Subscript> region at geomagnetic midlatitudes of the Southern and Northern hemispheres in going from summer to winter conditions at high solar activity

The structure and dynamics of the ionosphere and plasmasphere at high solar activity under quiet geomagnetic conditions of June 2–3, 1979, and January 5–6, 1980, over Millstone Hill station and Argentine Islands ionosonde, the locations of which are approximately magnetically conjugate, have been theoretically calculated. The plasma drift velocity, determined by comparing the calculated and measured heights of the F ₂ layer maximum (hmF2), and the correction of [N₂] and [O₂], found in the NRLMSISE-00 model, make it possible to coordinate the electron densities (NmF2) calculated at the hmF2 height and the measured anomalous variations in NmF2 over the Argentine Islands ionosonde as well as the calculated and measured NmF2 and electron temperature at the hmF2 height over Millstone Hill station. It has been shown that, if the interference of the diffusion velocities of O⁺(⁴S) and H⁺ ions is taken into account, the additional heating of plasmaspheric electrons leads to an increase in the flux of O⁺(⁴S) ions from the topside ionosphere to lower F ₂ layer altitudes, as a result of which an anomalous nighttime increase in NmF2 6, observed on January 6, 1980, over Millstone Hill station, is mainly produced. The second component of the formation of anomalous night-time NmF2 is the plasma drift along the magnetic field caused by the neutral wind, which shifts O⁺(⁴S) ions to higher altitudes where the recombination rate of O⁺(⁴S) with N₂ and O₂ is lower and slows down a decrease in NmF2 in the course of time. It has been shown that the influence of electronically excited O⁺ ions and vibrationally excited N₂ and O₂ molecules on electron density (N _e ) considerably differs under winter and summer conditions. This difference forms significant part of the winter anomaly in N _e at heights of the F ₂ region and topside ionosphere over Millstone Hill station.     

哀牢山中山湿性常绿阔叶林空心树木质残体呼吸作用初步研究

对云南哀牢山中山湿性常绿阔叶林空心树木质残体雨季和干季的呼吸速率进行测定,并对木质残体呼吸速率与木质密度和含水量之间的相关关系进行比较,分析了呼吸速率对温度的敏感性.结果表明:树干表层木质残体雨季呼吸速率显著高于树干内层和洞内的(p＜0.05),干季三个部位木质残体呼吸速率之间差异不显著(p＞0.05).含水量和呼吸速率存在季节差异,在树干表层和洞内雨季的含水量和呼吸速率显著高于干季的(p＜0.05),而在树干内层季节差异不显著(p＞0.05).三个部位木质残体密度与呼吸速率在雨季显著负相关(p＜0.01),三个部位的含水量和呼吸速率在雨季和干季都显著正相关(p＜0.01);木质残体的温度系数(Q10)大小顺序为:洞内(2.08)＞树干表层(2.01)＞树干内层(1.73),树洞内部木质残体对温度响应最敏感.哀牢山地区干季空心树木质残体较低的含水量和全年温凉的气候条件可能成为该区中山湿性常绿阔叶林空心树木质残体分解重要的限制因子.     

试论粉喷桩地基承载力计算

本文就粉喷桩在地其中的作用进行了分析,求得复合地基与群桩效应间的关系和一些有益的结论,并对粉喷桩的最佳尺度及负摩擦等问题提出了建议。     

Longitudinal effect in the dependence of the critical frequency of the midlatitude <Emphasis Type="Italic">E</Emphasis> layer on solar activity

Variations in the critical frequency of the E layer, foE, measured at Boulder and Tashkent stations located at almost coinciding geographical latitudes but at strongly different geomagnetic latitudes are analyzed. The following conclusions are drawn. (a) Late in the fall and in the winter, the foE values at these stations are distinctly different at low solar activity. This difference decreases with increasing solar activity. In other words, the longitudinal effect in the foE dependence on solar activity is significant for these conditions. (b) This effect is almost absent in summer; i.e., the difference in foE dependence on solar activity at these stations is insignificant for the given season. It has been substantiated that the dependence of the nitric oxide concentration [NO] on geomagnetic latitude, season, and solar activity is one of the main causes of this longitudinal effect.     

地震资料极性判别技术在储层预测中的应用

在储层地震属性预测技术研究方面,过去人们关注的焦点主要集中于地震关键面时窗选取、地震属性选择和地震属性优化及融合等方面,很少注意到地震资料极性对储层预测效果的影响。实际应用表明,地震资料的极性判断错误,可能导致储层地震属性预测失败。针对这些问题,文章在论述如何判别地震极性的基础上,利用地震属性技术对渤海海域某构造储层的横向展布进行预测,取得了较好的效果。     

Model of the E-Layer Critical Frequency for the Auroral Region

Geomagnetism and Aeronomy - A new foE model for the auroral region is constructed; the model is based on an analysis of the models of auroral electron precipitations, the boundaries of the discrete...     

Analysis of multiwell pumping tests in a confined aquifer under variations in the production rate and atmospheric pressure

Problems of the interpretation of long-term multiwell pumping tests that account for variations in the production rate and atmospheric pressure are considered. The barometric efficiency and corrections of actual drawdowns are calculated for the Udomlya groundwater basin; spatiotemporal development of the depression cone is analyzed. The hydrogeodynamic parameters are used for calibration of a numerical model of the groundwater basin and prediction of the periodic compensation water system for recharging the cooling lakes of the Kalinin Nuclear Power Plant.     

海洋激光测深技术介绍

介绍了机载激光海洋测深技术的原理、特点 ;简述了系统的组成和主要技术指标 ;概述了其发展历程、关键技术 ;分析了该项技术的发展趋势 ;最后对该项技术的应用前景进行了展望