Synchronous <Emphasis Type="Italic">UBVR</Emphasis> photometry and spectroscopy of DI Cephei

We present our synchronous spectroscopy and photometry of DI Cep, a classical T Tauri star. The equivalent widths and radial velocities of the individual components and Hα, Hβ, D1 and D2 Na I, and HeI λ5876 Å emission line profiles exhibit variability. We have found a clear positive correlation between the brightness and equivalent width for the Hα and Hβ emission lines. The photometric and spectroscopic data are satisfactorily described in phases of a 9-day period. The expected magnetic field of the star has been estimated using existing magnetospheric models to be 655–1000 G. The star is suspected to be a binary.     

三种扇贝挥发性风味物质指纹图谱分析

为探究海湾扇贝(Argopecten irradians)、栉孔扇贝(Chlamys farreri)、虾夷扇贝(Patinopecten yessoensis)三种扇贝闭壳肌的挥发性风味物质差异,采用气相色谱-离子迁移谱(gas chromatography-ion mobility spectroscopy,GC-IMS)技术,对三种扇贝闭壳肌在新鲜(40℃)和加热(100℃)情况下进行挥发性成分分析。结果表明:在新鲜状态下,海湾扇贝(HWSB-F)、栉孔扇贝(ZKSB-F)、虾夷扇贝(XYSB-F)闭壳肌中,共定性出27种挥发性风味物质,其中醛类8种,醇类5种,酮类5种,酯类3种,以及醚类、苯类、酸类、烯类和噻唑等。在加热情况下,海湾扇贝(HWSB-C)、栉孔扇贝(ZKSB-C)、虾夷扇贝(XYSB-C)闭壳肌中共定性出52种挥发性风味物质,其中醛类20种,酯类5种,酮类7种,醇类8种,烯类4种,酸类2种,醚类2种,还包括吡嗪、胺类、苯类、含氧杂环等物质。对三种扇贝闭壳肌新鲜组和加热组指纹图谱进行分析,发现新鲜扇贝原有的挥发性风味物质加热后减少,且产生了新的其他种类的挥发性风味物质。扇贝闭壳肌加热组的挥发性风味物质种类较多,组成比较复杂,新鲜组的扇贝闭壳肌挥发性风味物质种类较少,组成简单。通过主成分分析,可在新鲜状态和加热状态下,有效区分三种扇贝闭壳肌组织。三种扇贝闭壳肌挥发性风味物质指纹图谱的建立,丰富了不同扇贝呈味物质的组成成分研究内容,证明GC-IMS技术可快速鉴别三种去壳扇贝闭壳肌的种类,为不同种扇贝闭壳肌以次充好提供检测依据。     

一类信号恢复问题的投影迭代硬阈值算法

本文给出了基于L₀模求解该问题的非凸模型,借助于稀疏正则化方法来克服问题的不适定性。该模型利用紧小波框架对信号进行稀疏逼近,并利用L₀模度量稀疏性。提出了求解该模型的投影迭代硬阈值算法,并证明了算法的全局收敛性。该算法每一步都有闭式解,计算过程简洁高效。数值实验表明,方法在重建信号的视觉质量和量化指标方面均优于所对比的pFISTA方法。     

新疆阿尔泰伟晶岩中绿柱石拉曼光谱特征研究——以可可托海3号脉与阿祖拜328、528号脉为例

本文对新疆可可托海3号伟晶岩脉中的绿柱石与阿祖拜328、528号伟晶岩脉中的宝石级绿柱石开展拉曼光谱对比研究,获得以下主要结论: ① 阿祖拜328、528号伟晶岩脉中宝石级绿柱石以富含Ⅰ型H₂O为特征,可可托海3号脉早期形成的结构带(Ⅰ-Ⅱ带)中绿柱石以及相对富H₂O岩浆体系中形成的绿柱石(Ⅳ带)以存在Ⅰ型H₂O为主,演化程度相对较高,岩浆体系中结晶的结构带(Ⅲ带)以及岩浆-热液过渡阶段体系形成的结构带(Ⅴ带)中绿柱石以含有Ⅱ型H₂O为特征; ② 在可可托海3号脉以及阿祖拜328号、528号脉绿柱石矿物中均发现冰晶石矿物包体,指示伟晶岩岩浆含有较高的F含量;③ 绿柱石通道水类型(Ⅰ型H₂O、Ⅱ型H₂O)及相对比例,是伟晶岩岩浆-热液演化过程及其形成条件的响应,在相对氧化的岩浆体系中主要形成绿柱石矿物,而相对还原的富H₂O岩浆体系更有利于海蓝宝石形成.     

微波消解—冷原子荧光光谱法测定植物样品中的汞

为了简化测量植物中汞含量的方法,提高灵敏度及结果的可信度,实验采用微波消解植物样品的办法,使样品经氯化亚锡还原,再用冷原子荧光测定出植物样品中汞的含量。确定了消解样品的方法和微波消解样品的条件,优化了仪器的最佳工作参数。方法检出限0.30×10-9(稀释因子100倍),精密度(n=12)在2.09%~6.05%,加标回收率94.1%~105.5%,方法经生物国家一级标准物质验证方法准确可靠。     

Raman spectroscopic analysis of cyanobacterial colonization of hydromagnesite, a putative martian extremophile

Raman spectra of an extremophile cyanobacterial colony in hydromagnesite from Lake Salda in Turkey have revealed a biogeological modification which is manifest as aragonite in the stratum associated with the colony. The presence of key spectral biomarkers of organic protectant molecules such as β-carotene and scytonemin indicate that the survival strategy of the cyanobacteria is significantly one of UV-radiation protection. The terrestrial location of this extremophile is worthy of consideration further because of its possible putative link with the “White Rock” formations in Sabaea Terra and Juventae Chasma on Mars.     

The symbiotic star CH Cygni – I. Non-thermal bipolar jets

Very Large Array surface brightness and spectral index maps of the evolving extended emission of the triple symbiotic star CH Cygni are presented. These are derived from observations at 4.8, 8.4 and 14 GHz between 1985 and 1999. The maps are dominated by thermal emission around the central bright peak of the nebula, but we also find unambiguous non-thermal emission associated with the extended regions. Our observations confirm that this is a jet. The central region has been associated with the stellar components through Hubble Space Telescope imaging. If the jets are the result of ejection events at outburst, expansion velocities are consistent with those from other measurement methods. We propose that the non-thermal emission is caused by material ejected in the bipolar jets interacting with the circumstellar wind envelope. The resulting shocks lead to local enhancements in the magnetic field from the compact component of the order of 3 mG.