Confirmation of eclipses in KPD 0422+5421, a binary containing a white dwarf and a subdwarf B star

We report additional photometric CCD observations of KPD 0422+5421, a binary with an orbital period of 2.16 h which contains a subdwarf B star (sdB) and a white dwarf. There are two main results of this work. First, the light curve of KPD 0422+5421 contains two distinct periodic signals, the 2.16-h ellipsoidal modulation discovered by Koen, Orosz & Wade and an additional modulation at 7.8 h. This 7.8-h modulation is clearly not sinusoidal: the rise time is about 0.25 in phase, whereas the decay time is 0.75 in phase. Its amplitude is roughly half of the amplitude of the ellipsoidal modulation. Secondly, after the 7.8-h modulation is removed, the light curve folded on the orbital period clearly shows the signature of the transit of the white dwarf across the face of the sdB star and the signature of the occultation of the white dwarf by the sdB star. We have used the Wilson–Devinney code to model the light curve to obtain the inclination, the mass ratio and the Ω potentials, and a Monte Carlo code to compute confidence limits on interesting system parameters. We find component masses of     and     ( M _total     , 68 per cent confidence limits). If we impose an additional constraint and require the computed mass and radius of the white dwarf to be consistent with a theoretical mass–radius relation, we find     and     (68 per cent confidence limits). In this case the total mass of the system is less than 1.4 M_⊙ at the 99.99 per cent confidence level. We briefly discuss possible interpretations of the 7.8-h modulation and the importance of KPD 0422+5421 as a member of a rare class of evolved binaries.     

UBV photometry, UV spectroscopy and radio observations of the peculiar binary V Sagittae

We have performed high-speed UBV photometric observations on the peculiar binary V Sagittae. Using three new eclipse timings we update the orbital ephemeris and convert it to a dynamical time-scale (TDB). We also searched for quasi-periodic oscillations but did not detect them. Using the Wilson–Devinney algorithm we have modelled the light curve to find the stellar parameters of V Sge. We find that the system is a detached binary but that the primary star is very close to filling its Roche lobe, while the secondary star fills 90 per cent of its Roche lobe volume. We find temperatures of the primary and the secondary star to be T ₁=41 000 K and T ₂=22 000 K. We find i =72° and masses of 0.8 M_⊙ and 3.3 M_⊙ for the primary and secondary stars respectively. De-archived Hubble Space Telescope ( HST ) spectroscopy of V Sge shows evidence of mass loss via a wind or winds. In addition we report radio observations of V Sge during an optical high state at 2 cm, 3.6 cm and 6 cm wavelengths. The 3.6 cm emission is increased by a factor of more than six compared with an earlier detection in a previous optical high state.     

Non-linear behaviour of the pulsating white dwarf G29-38 – III. Relative amplitudes of the cross-frequencies

In each season when the DA pulsating white dwarf G29-38 has been observed, its period spectrum appears very different, but it always contains a forest of harmonics and cross-frequencies. The ratio of the amplitude of these non-linear frequencies A _c to the product of the amplitudes of the corresponding parent modes A ₁ A ₂ has been measured. The results are compared with the predictions given by three existing theoretical models. Our analysis shows that the non-linear frequencies present in the period spectrum of G29-38 owe their presence mostly to the inelastic response of the stellar medium to the perturbation travelling through it, rather than to the non-linear response of the emergent luminous flux to the surface temperature variation. This analysis also confirms that most identified modes are ℓ=1, as previously asserted by Kleinman et al.     

全孔反循环中心取样钻进设备与试验研究

气动贯通式潜孔锤与双壁钻杆及专门研制的反循环钻头(获国家发明专利)配套使用,可实现反循环连续取心(样)钻进新工艺,连续获取的岩样采取率高,品质好,代表性强。经复杂地层金矿、铜矿等矿区使用,钻进效率比普通钻进方法提高3倍,成本降低为原成本的1/8~1/5,有效解决了复杂地层矿床勘探和取心钻进难题。      

太原市供水风险和外区调水水价预测

提出了太原市2000～2030年期间高、中、低三种需水量预测方案,进行了未来规划期降水、径流和地下水资源的人工系列生成并定量分析了上述规划期内的供水风险及其变化过程。对引黄济并工程,计算了不同调水量的使用概率,结合工程水价的经济分析,对规划期内外调水的期望水价进行了定量评价。     

地面核磁共振找水仪及其在水文地质调查工作中的应用研究

本文概要介绍了地面核磁共振找水方法的原理和世界上最新的直接探查地下水的仪器设备--地面核磁感应系统的特点,并以实例说明了NMR找水方法的应用效果,提出了关于提高NUMIS系统抗干扰能力、完善解释方法、研制系列仪器等方面的建议.     

“引江济星”工程及风场环境影响广东肇庆星湖水龄分布特征

目前大量景观类湖泊在人工布局下呈现形状不规整的特点,容易造成湖湾水体滞留形成死水区,水质恶化问题日益突出,本文以星湖为研究区域,建立基于环境流体生态动力学(EFDC)模型的星湖水动力—风场耦合模型,以水龄作为衡量水体交换速率的指标,设计12种工况模拟计算不同出入湖通道布局及流量配比、"引江济星"工程和风场对星湖水龄时空分布的影响.结果表明:星湖水龄存在季节性和空间性分布差异,春季主导风向与湖体流动主方向互斥,抑制了波海湖水体交换,导致水龄在春季较长,而秋季南西南季风促进中心湖等水体交换,致使水龄偏短,也反映出风向的影响存在湖区空间异质性,风向为南东南时星湖整体水龄最小;入湖口通道布局及流量配比对湖区水体交换速率存在影响,以外坑为波海湖入湖口且波海湖、中心湖、仙女湖入流比为4∶3∶3时,星湖整体水龄最小,拟建的青莲湖出水口和仙女湖出水口能有效加快青莲湖东北部和仙女湖东南部的水体交换速率;综合考虑调水引流效益、经济投资、生态开发和占地的成本,方案二为最优调水引流方案.本研究强调入湖口布局、流量大小和比例、及风场等因素对城市内湖水体置换的影响,为人为干扰下的景观湖泊的治理和管控提供科学支撑.     

焦家金矿选厂旋流器溢流产品工艺矿物学分析

焦家金矿选矿厂目前的日处理量达12000吨/天,金回收率92%。选矿厂已将破碎段产品用双螺旋分级机洗矿,洗矿的矿泥产率为7%,矿泥单独浮选,整体工艺初步实现了泥砂分选。为进一步提高选金回收率,流程改造拟将磨矿-浮选系统的旋流器溢流产品二次分级,分级的次生矿泥与洗矿矿泥进入矿泥浮选系统一并浮选,为了掌握旋流器溢流产品的性质,本文采用偏光反光两用显微镜、扫描电镜、X射线衍射仪、红外光谱和差热分析等手段进行研究。研究结果表明矿物种类主要是金属硫化物和脉石矿物,金属硫化物约占4%,脉石约占96%,金属硫化物主要是黄铁矿(70.17%)和黄铜矿(16.27%),脉石主要是石英(47.12%)和长石(15.90%)。黄铁矿和石英是重要的载金矿物,黄铁矿含金65%,石英含金20%。颗粒越细,单体颗粒含量越高,连生体颗粒含量越少;颗粒越细,黄铁矿含量越高,Au、Ag分布率越高,-0.037 mm粒级中黄铁矿含量达到73.58%,Au、Ag占到47.99%和56.60%,金分配率与黄铁矿含量成正相关;粗粒级中未发现金颗粒,中等粒级中次显微金约占30%,细粒级中次显微金约40%,金粒径在2~10μm范围内;金形状有三角形、棱角状、小粒状、不规则状等。红外光谱与差热曲线研究发现颗粒越细矿物成分趋于复杂。研究结论为磨矿分级产生的次生矿泥浮选调控提供了依据,对矿泥浮选的药剂制度调控、浮选流程确定等具有重要实际意义。     

金属资源的紧缺与隐伏矿找矿的思考

我国金属资源的紧缺,不是资源的匮乏,而是对隐伏矿找矿的不力.就空间而论,隐伏矿只是埋藏较深的矿床,它不涉及地质成矿的新理论.需要解决的是深部找矿的能力,要求找矿方法与技术有新的突破.当前矿山开采的深度可达1km左右,据此,要求隐伏矿找矿的深度至少应该达到开采深度,地质(物理)填图达到2～3km的深度,是完全必要的.地球物理在深部探测方面具有相对优势.但现有地面地球物理方法,尚不能满足隐伏矿找矿的需要,应加大科研力度,依靠基础研究,有望3～5年的时间,能有系列的新方法与新技术的出现,满足隐伏矿的有效勘查.由于隐伏矿找矿失去了矿产的直接信息,只能依靠深部探测的方法、技术,得到间接信息.间接信息的欠定性,会给找矿带来高风险性.为了降低高风险的巨大损失,除应具备足够的有效信息量外,还必须对信息表述的对象,进行去粗取精、去伪存真的分析与研究.而基于不同知识背景的多学科,对信息的综合研究,能最大限度地将信息的欠定性转化为矿产的专属性,从而发现隐伏矿床.建立多学科互补、合作的找矿机制,是找矿的必然要求,也是矿产资源部门体制改革的重点.