对当代大学生婚前性行为的反思

婚前性行为是个极为敏感而又不得不面对的话题。本文通过调查了解大学生的性观念和性行为取向,为高校的性教育及大学生的健康成长提供参考与借鉴。     

美国的中性浮力模拟器及其应用

中性浮力地面模拟试验不仅可以用来训练航天员,对大型空间结构的设计及在轨组装与维修技术研究也具有重要的作用.文章对美国的三台大型中性浮力模拟器的性能、规模和配置及几次典型的大型空间结构的中性浮力模拟试验作了介绍.     

空间太阳X射线成像望远镜技术

阐述了空间太阳X射线成像望远镜(SXT)在近地环境空间天气观测中的作用和意义。介绍了国内外SXT技术的发展和应用情况，分析了仪器的工作原理、主要观测目标和应具备的基本功能以及关键部件。     

Dynamical characterization of the last prolonged solar minima

The planetary hypothesis of the solar cycle is an old idea in which the gravitational influence of the planets has a non-negligible effect on the causes of the solar magnetic cycle. The advance of this hypothesis is based on phenomenological correlations between dynamical parameters of the Sun’s movement around the barycentre of the Solar System and sunspots time series; and more especially, identifying relationships linking solar barycentric dynamics with prolonged minima (especially Grand Minima events). However, at present there is no clear physical mechanism relating these phenomena. The possible celestial influence on solar cycle modulation is of great importance not only in solar physics but also in Earth sciences, because prolonged solar minima have associated important climatic and telluric variations, in particular, during the Maunder and Dalton Minimum. In this work we looked for a possible causal link in relation with solar barycentric dynamics and prolonged minima events. We searched for particular changes in the Sun’s acceleration and concentrated on long-term variations of the solar cycle. We show how the orbital angular momentum of the Sun evolves and how the inclination of the solar barycentric orbit varies during the epochs of orbital retrogressions. In particular, at these moments, the radial component of the Sun’s acceleration (i.e., in the barycentre-Sun direction) had an exceptional magnitude. These radial impulses occurred at the very beginning of the Maunder Minimum, during the Dalton Minimum and also at the maximum of cycle 22 before the present extended minimum. We also found a strong correlation between the planetary torque and the observed sunspots international number around that maximum. We apply our results in a novel theory of Sun–planets interaction that it is sensitive to Sun barycentric dynamics and found a very important effect on the Sun’s capability of storing hypothetical reservoirs of potential energy that could be released by internal flows and might be related to the solar cycle. This process begins about 40 years before the solar angular momentum inversions, i.e., before Maunder Minimum, Dalton Minimum, and before the present extended minimum. Our conclusions suggest a dynamical characterization of peculiar prolonged solar minima. We discuss the possible implications of these results for the solar cycle including the present extended minimum.     

空管中带班主任管理模式研究

通过对中国空中交通管制中带班主任管理模式研究，提出了适用于该管理模式的权变-行为混合管理模型。采用对比研究方法，分析了传统的权变管理模型、行为管理模型等当今流行管理学理论和模型，从而提出了权变-行为混合管理模型。通过一线带班主任的反馈，能够最大限度调动发挥全班组人员的主观能动性和积极性，合理地组织人力、物力，从而预防和消除人为差错，提高管制工作效率。     

Testing anti-fungal activity of a soil-like substrate for growing plants in bioregenerative life support systems

The object of this research is to study a soil-like substrate (SLS) to grow plants in a Bioregenerative Life Support System (BLSS). Wheat and rice straw were used as raw materials to prepare SLS. Anti-fungal activity of SLS using test cultures of Bipolaris sorokiniana, a plant-pathogenic fungus which causes wheat root rot was studied. Experiments were conducted with SLS samples, using natural soil and sand as controls. Infecting the substrates, was performed at two levels: the first level was done with wheat seeds carrying B. sorokiniana and the second level with seeds and additional conidia of B. sorokiniana from an outside source. We measured wheat disease incidence and severity in two crop plantings. Lowest disease incidence values were obtained from the second planting, SLS: 26% and 41% at the first and the second infection levels, respectively. For soil the values were 60% and 82%, respectively, and for sand they were 67% and 74%, respectively. Wheat root rot in the second crop planting on SLS, at both infection levels was considerably less severe (9% and 13%, respectively) than on natural soil (20% and 33%) and sand (22% and 32%). SLS significantly suppressed the germination of B. sorokiniana conidia. Conidia germination was 5% in aqueous SLS suspension, and 18% in clean water. No significant differences were found regarding the impact on conidia germination between the SLS samples obtained from wheat and rice straw. The anti-fungal activity in SLS increased because of the presence of worms. SLS also contained bacteria stimulating and inhibiting B. sorokiniana growth.     

基于聚类分析的长沙市民体育休闲行为意向分异研究

城市居民作为体育休闲市场的主体,对其行为意向展开研究,对于发现城市体育休闲市场一般特征、开拓相关体育休闲市场等具有重要意义。通过对长沙市民抽样调查得到基础数据,运用聚类法得出3类意向不同的细分市场,采用对应分析方法对各细分市场的体育休闲意向进行分析,得出不同类型的细分市场的体育休闲意向有显著差异的结论,因而获得了体育休闲市场营销的启示。     

Synoptic magnetic field in cycle 23 and in the beginning of the cycle 24

The SOHO/MDI data provide the uniform time series of the synoptic magnetic maps which cover the period of the cycle 23 and the beginning of the cycle 24. It is very interesting period because of the long and deep solar minimum between the cycles 23 and 24. Synoptic structure of the solar magnetic field shows variability during solar cycles. It is known that the magnetic activity contributes to the solar irradiance. The axisymmetrical distribution of the magnetic flux (Fig. 3c) is closely associated with the ‘butterfly’ diagram in the EUV emission (Benevolenskaya et al., 2001). And, also, the magnetic field (B_∥) shows the non-uniform distributions of the solar activity with longitude, so-called ‘active zones’, and ‘coronal holes’ in the mid-latitude. Polar coronal holes are forming after the solar maxima and they persist during the solar minima. SOHO/EIT data in the emission of Fe XII (195 Å) could be a proxy for the coronal holes tracking. The active longitudinal zones or active longitude exist due to the reappearance of the activity and it is clearly seen in the synoptic structure of the solar cycle. On the descending branch of the solar cycle 23 active zones are less pronounced comparing with previous cycles 20, 21 and 22. Moreover, the weak polar magnetic field precedes the long and deep solar minimum. In this paper we have discussed the development of solar cycles 23 and 24 in details.     

Perspective on space radiation for space flights in 2020–2040

The Sun undergoes several well known periodicities in activity, such as the Schwabe 11 year cycle, the Gleissberg 80–90 year cycle, the Suess 200–210 year cycle and the Halstatt 2200–2300 year cycle. In addition, there is evidence that the 20th century levels of solar activity are unusually high. The years 2020–2040 are expected to coincide with increased activity in human space flight beyond low Earth orbit. The solar cycles and the present level of solar activity are reviewed and their activities during the years 2020–2040 are discussed with a perspective on space radiation and the future program of space flight. It is prudent to prepare for continuing levels of high solar activity as well as for the low levels of the current deep minimum, which has corresponded to high galactic cosmic ray flux.     

The effect of solar–geomagnetic activity during hospital admission on coronary events within 1 year in patients with acute coronary syndromes

Some evidence indicates the deterioration of the cardiovascular system during space storms. It is plausible that the space weather conditions during and after hospital admission may affect the risk of coronary events in patients with acute coronary syndromes (ACS). We analyzed the data of 1400 ACS patients who were admitted to the Hospital Lithuanian University of Health Sciences, and who survived for more than 4 days. We evaluated the associations between geomagnetic storms (GS), solar proton events (SPE), and solar flares (SF) that occurred 0–3 days before and after hospital admission and the risk of cardiovascular death (CAD), non-fatal ACS, and coronary artery bypass grafting (CABG) during a period of 1 year; the evaluation was based on the multivariate logistic model, controlling for clinical data. After adjustment for clinical variables, GS occurring in conjunction with SF 1 day before admission increased the risk of CAD by over 2.5 times. GS 2 days after SPE occurred 1 day after admission increased the risk of CAD and CABG by over 2.8 times. The risk of CABG increased by over 2 times in patients admitted during the day of GS and 1 day after SPE. The risk of ACS was by over 1.63 times higher for patients admitted 1 day before or after solar flares.