黑洞候选体MAXI J1535-571爆发期间的时变现象

利用“慧眼”(Hard X-ray Modulation Telescope, Insight-HXMT)卫星在2017年9月对黑洞候选体MAXI J1535-571的观测数据,研究了该源在爆发期内的时变现象.当源处于不同的爆发谱态时,功率密度谱的谱型存在明显差异.在硬中间态,有明显的限带噪声(band-limited noise)成分和QPO (Quasi-Periodic Oscillation)成分.分析结果表明:低频限带噪声的特征频率随能量的变化呈现正相关,即软能段光子的特征频率小于硬能段光子的特征频率. 0.1–0.5 Hz频率区间的限带噪声RMS (Root Mean Square)谱在硬中间态和软中间态均出现峰值,且在高能端存在差异,可能是主导噪声RMS的能谱成分占比不同.当谱态由硬中间态过渡到软中间态时, C型QPO的RMS谱保持相似趋势,但限带噪声RMS谱存在谱态依赖现象,暗示着噪声和QPO有不同的起源机制.     

Seasonal change in body length of important small copepods and relationship with environmental factors in Jiaozhou Bay,China

Differences among species in prosome length and in species’ response to environmental factors do exist. Therefore, it is useful to examine prosome length for different copepod species in variable environments. Seasonal variations in prosome length of four small copepods and their copepodite stages in the Jiaozhou Bay were compared and the relative influence of temperature, salinity, and chlorophyll concentration were examined. Two peaks were found in the mean prosome length of Paracalanus parvus (in early winter and May). For Acartia bifilosa, the maximum values of all copepodites occurred mainly from February to April, and decreased to the bottom in July. Prosome length of Acartia pacifica peaked when it first appeared in June, then reached to the minimum in July. Parvocalanus crassirostris only appeared from late summer to autumn and the mean prosome length showed no clear changes. Correlations of adult prosome length with environmental factors were evaluated. For the four species, temperature was negatively correlated to prosome length except for P. crassirostris. But the different species varied markedly in their responds to temperature. A. bifilosa showed a more definite trend of size variation with temperature than P. parvus and A. pacifica. Correlations of prosome length with salinity were significantly positive for almost all the small copepods. The relationship between chlorophyll concentration and prosome length was complicated for these copepods, but for P. parvus, chlorophyll concentration was also an important affecting factor. Furthermore, investigation needs to be done on food quality for some copepod. These results are essential to estimate the biomass and the production, and to understand these small copepods’ population dynamics in this human-affected bay.     

温度和饵料对双刺纺锤水蚤产卵率和孵化率的影响

Acartia bifilosa (Copepoda: Calanoida) is a common species in offing of global waters and it often becomes dominant species in some estuaries. This species develops different strategy according to variation of environment. Despite its ecological role, Acartia bifilosa also has been concerned as live feeds in aquaculture, but study on egg production rate of this species in saturated diet in different temperature and different diet is so far not available. In order to interpret the importance of temperature and diet on natural population variation and also on aquaculture as foods of larval fish, the functional response of reproductive success of Acartia bifilosa was quantified in the laboratory using different temperatures and diets. Acartia bifilosa was captured in Jiaozhou Bay and acclimated to corresponding temperature for 3~4 days. In order to reduce the effect of large extent temperature range on organism, we captured Acartia bifilosa from March to June and acclimated them to temperature which is adjacent to natural temperature. Daily egg production rate (EPR, eggs female-1day-1) was detected for 11~15 days at 5 different temperatures ranged from 8.0 to 23 °C and all the females was feed on saturated diet all through the experiments. EPR on first day was not calculated in the mean EPR to eliminate the effect of different diets. This result showed that Acartia bifilosa spawned continuously during the experiment days and no obvious regulation was found. EPR was positively correlated with temperature from 8.0 to 23 °C. The highest mean EPR was observed at 23 °C (7.3 eggs female-1day-1), and the lowest value was found at 8 °C (3.8 eggs female-1day-1). The effect of diets on EPR was evaluated at two different temperatures (8.0 °C and 12.5 °C). Same trends were found at the two temperatures: mean EPR fed on Chaetoceros sp. was higher than that fed on Skeletonema costatum, and during the 14-day experiments, EPR was higher for females fed on Skeletonema costatum than chaetoceros sp. in the first few days (3~5 days), but it changed reversely in the subsequent days until the end of the experiments. Hatched eggs were observed in the two experiments at temperature 8°C and 12.5 °C and no diapause eggs were found. The hatching success rate was low at 8°C but reached 93.2% at 12.5 °C. According to the results in this paper, we detected the comfortable temperature range for EPR, and evaluated the effect of Skeletonema costatum which often brings out red tide in natural waters. These results are beneficial to ecological research for explaining population variation and population recruitment of this species, These data also can be used in Acartia bifilosa aquaculture.     

冬、夏季青藏高原地面加热场激发的500hPa遥相关型

本文用青藏高原地面加热场强度来表征高原的加热状况，并用统计的方法，分析了冬季（２月）和夏季（７月）青藏高原地面加热场强度与同期５００ｈＰａ位势高度的遥相关关系，得到如下结论：冬季高原地面加热场可激发北半球５００ｈＰａ产生遥相关型，这种遥相关型可看成是二维Ｒｏｓｓｂｙ波列由低纬向东北方向传播；夏季高原地面加热场可激发北半球５００ｈＰａ产生类似于ＥＵ型的遥相关，这种遥相关型可看成二维Ｒｏｓｓｂｙ波列由     

白令海蓝细菌分布

1999年 7月～ 9月中国首次北极考察期间 ,研究了白令海 2个断面 8个站位海洋蓝细菌数量分布。蓝细菌数量变化在 0～ 7.93× 1 0 3 cell/ml之间 ,水平分布自南向北随纬度的增高而降低 ,在 6 0°N以北的 B1 - 1 2站没有检测到蓝细菌。垂直分布主要分布于 5 0 m以浅 ,最大值出现在B1 - 1站的 2 5 m水深。蓝细菌数量在 5 0 m以下迅速减少 ,到 1 5 0 m水深几乎没有。海水温度和NH+ 4 - N可能是影响蓝细菌数量分布的重要因素     

江汉盆地东部早中生代沉积地层碎屑云母成分:对大别高压-超高压岩石暴露作用的约束

碎屑白云母是碎屑岩中常见的、来自源区的稳定成分,可以用来指示源区性质,多硅白云母是碰撞造山高压-超高压变质岩石的特征矿物。对大别造山带同造山期沉积而成的江汉盆地东部上三叠统-中侏罗统砂岩碎屑白云母化学成分研究表明:上三叠统该区地层砂岩中碎屑白云母多以低硅白云母(Si<3.2)为特征,暗示此时大别造山带高压-超高压岩石很可能没有出露地表;自下侏罗统开始,砂岩中碎屑白云母中多硅白云母(Si>3.3)大量出现,中侏罗统砂岩多硅和低硅白云母发育,表明大别高压-超高压岩石在早侏罗世即已出露地表并经剥蚀搬运至盆地。这一结果从沉积学角度为约束高压-超高压岩石的折返时序和大别造山带演化提供了新的资料。     

浙江浦江晚中生代埃达克质火山岩的成因

浙江浦江地区白垩纪劳村组存在一套独特的中酸性火山岩,其主量元素表现出富 Al_2O_3(>16%)和 Na_2O(4.01%～4.52%),高 Na_2O/K_2O(1.94～5.51,平均2.89),高 Sr(583～643μg/g),贫 Y(11.4～13.2μg/g)和 HREE(如 Yb=1.16～1.26μg/g),以及低(~(87)Sr/~(86)Sr)_i(0.7041～0.7043)和高ε_(Nd)(t)(0.3～2.3)。这些火山岩在元素-同位素组成上明显不同于浦江地区或区域上的晚中生代中酸性火山岩,而与现代俯冲带产出的埃达克岩类似。由于这些岩石相对于晚中生代的基性岩浆具有更低的(~(87)Sr/~(86)Sr)_i 比值,因此难以通过玄武岩浆的分离结晶或同化混染作用来解释,最有可能是地壳部分熔融的产物,在构造背景方面,目前还没有确切的证据说明区域存在晚中生代洋壳的俯冲作用,我们倾向于认为劳村组埃达克质火山岩可能为新增生玄武质地壳部分熔融的结果,其形成与区域上中生代地壳增生作用有直接的动力学联系。     

2005年11月26日九江--瑞昌5.7级地震浅析

2005年11月26日,在江西省九江县与瑞昌市交界处发生5.7级地震,震源深度10km。宏观震中在九江县港口乡。震中烈度Ⅶ度,极震区为北东向的椭圆,烈度分布受瑞昌盆地内地形地貌条件的控制;5.7级地震的最大余震为ML5.3级,序列类型为主震—余震型,余震较丰富,余震区长轴为北西向。此次地震经历了较长期的应力应变积累过程,发生在江西分宜—黄海北部北东向ML≥4.0级地震活动带和湖北西部—江西南昌ML≥3.0级地震活动带的交汇部位,与大区域地震活动性中长期异常相关。     

基于RTCM数据格式的虚拟参考站技术算法研究

虚拟参考站技术是网络RTK的一种,它以众多的优势代表了网络RTK的主要发展趋势。本文介绍了VRS系统的工作原理,详细推导了VRS的数学模型,针对差分改正信息,提出了综合误差内插算法,分析了RTCM数据格式的特点及其在VRS技术中的应用,并做了实验验证,结合编程计算,证明了本文中VRS数学模型的正确性,为虚拟参考站系统的进一步研究提供依据。