This paper reports results from the first long-term BV(RI)c photometric CCD observations of three variable pre-main-sequence stars collected during the period f
We present the observational results from a detailed timing analysis of the black hole candidate EXO 1846-031 during its outburst in 2019 with the observations
In this work,we train three decision-tree based ensemble machine learning algorithms (Random Forest Classifier,Adaptive Boosting and Gradient Boosting Decision
The first BV bands photometric observations and the low-resolution spectrum of the shortest period Am type eclipsing binary TYC 6408-989-1 have been obtained.Th
For lots of scientific questions about lunar physics deep inside the Moon,in-situ observation on lunar physical libration is one of the most potential ways.In t
It is widely believed that magnetic reconnection plays an important role in various eruptive phenomena of space and astrophysical plasmas.The mechanism of anoma
气井的稳产时间是生产部门进行合理配产时需要考虑的主要因素,也是影响气藏最终采收率的主要因素,所以准确预测气井稳产时间对于气井(藏)科学开发具有重要意义。目前能够较准确预测气井稳产时间的是数值模拟法,其他方法如经验法、生产压差法、节点优化配产法等预测气井稳产时间,因其使用条件差异大,计算也较复杂,故在四川盆地东部地区实际生产中应用较少。以川东地区大量已结束稳产期气井的实际生产数据作为样本进行分析,发现影响气井稳产时间的主要因素是:①气井配产比;②剩余动态储量;③无阻流量。气井稳产时间受多因素影响,因此采用多
The surface accuracy of a large parabolic antenna is an important indicator to evaluate the quality of the antenna.It not only directly affects the antenna's ap
Masses of W Ursae Majoris-type(W UMa)binaries play a critical role in investigating stellar dynamical evolutionary status.In this paper,we combine the PARSEC(PA
南海高温高压气田采用丛式井模式,表层Ф660.4 mm井段集中批钻作业面临着上层隔水导管鞋易漏失、浅部松软地层钻进造斜率难保证、密集型井槽井眼碰撞的难题,限制了表层钻井的作业时效。为此,针对性地采取井槽防窜漏工艺、优化井眼预斜钻具组合、开展表层防碰设计及安全钻进参数控制,形成了适合该区域的丛式井表层Ф660.4 mm井段安全钻井关键技术。现场应用效果表明:①Ф660.4 mm井段钻井采用顺序“跳打”方式,在隔水导管内清淤,出隔水导管后实施钻进参数控制,并在固井时实施中间液附加量和排量控制,解决了表层大