Magnetic mineralogy of the Hongqiling Cu-Ni sulphide deposit: Implications for ore genesis

Pyrrhotite is one of the common ore minerals in Cu-Ni sulphide deposits, but only monoclinic pyrrhotite is ferromagnetic at room temperature. X-ray and EPA analyses reveal that most pyrrhotite forming sideronitic texture in the Hongqiling Cu-Ni sulphide deposit is monoclinic, but that in the massive ore is a mixture of monoclinic and hexagonal pyrrhotites. Differential thermal and magnetic- thermogravimetric analyses of massive ore indicate a magnetic transition and heat absorption at 323℃, suggesting that this temperature is the thermomagnetic and phase transition point of pyrrhotite. For massive pyrrhotite ores heated at 400oC for 30 h and then quenched by cool water, the monoclinic pyrrhotite (mpo) transforms completely into the hexagonal pyrrhotite (hpo). However, all the pyrrhotites resulting from slow cooling of the sample in air are mpo. These results indicate that transformation between hpo and mpo depends upon the cooling rate. Therefore, massive ores in this deposit might have been formed via rapid cooling of ore melts. On the other hand, it is significant to study the effect of the ratio of the magnetite in total ores on the genesis of magmatic Cu-Ni suphide deposits.     

Magnetic mineralogy of the Hongqiling Cu-Ni sulphide deposit: Implications for ore genesis

Pyrrhotite is one of the common ore minerals in Cu-Ni sulphide deposits, but only monoclinic pyrrhotite is ferromagnetic at room temperature. X-ray and EPA analyses reveal that most pyrrhotite forming sideronitic texture in the Hongqiling Cu-Ni sulphide deposit is monoclinic, but that in the massive ore is a mixture of monoclinic and hexagonal pyrrhotites. Differential thermal and magnetic- thermogravimetric analyses of massive ore indicate a magnetic transition and heat absorption at 323℃, suggesting that this temperature is the thermomagnetic and phase transition point of pyrrhotite. For massive pyrrhotite ores heated at 400oC for 30 h and then quenched by cool water, the monoclinic pyrrhotite (mpo) transforms completely into the hexagonal pyrrhotite (hpo). However, all the pyrrhotites resulting from slow cooling of the sample in air are mpo. These results indicate that transformation between hpo and mpo depends upon the cooling rate. Therefore, massive ores in this deposit might have been formed via rapid cooling of ore melts. On the other hand, it is significant to study the effect of the ratio of the magnetite in total ores on the genesis of magmatic Cu-Ni suphide deposits.     

噬菌体展示外源多肽的免疫原性研究

利用噬菌体展示技术将丝状噬菌体fd基因8克隆入pKK223-3质粒中，将白色念珠菌特异表位基因插入到修饰后的质粒载体中，并制备了杂合噬菌体，利用纯化的该表位抗原PA免疫小鼠，结果表明该噬菌体-表位抗原PA在有无佐剂存在的情况下均产生抗体，用ELISA方法采用双波长（450/630nm)检测抗体，其在有无佐剂存在的情况下光密度值无明显差别，免疫后小鼠脾淋巴细胞在有无佐剂的情况下均产生明显增殖，未见明显的毒副作用，具有良好的安全性，该方法产生的抗体与传统的合成多肽相比具有方法简便、低价高效等特点，它将成为生产高效低价疫苗的有效途径，该噬菌体-表位抗原PA为真菌疫苗的研制打下基础。     

A young massive planet in a star-disk system

There is a general consensus that planets form within disks of dust and gas around newly born stars. Details of their formation process, however, are still a matter of ongoing debate. The timescale of planet formation remains unclear, so the detection of planets around young stars with protoplanetary disks is potentially of great interest. Hitherto, no such planet has been found. Here we report the detection of a planet of mass (9.8+/-3.3)M(Jupiter) around TW Hydrae (TW Hya), a nearby young star with an age of only 8-10 Myr that is surrounded by a well-studied circumstellar disk. It orbits the star with a period of 3.56 days at 0.04 au, inside the inner rim of the disk. This demonstrates that planets can form within 10 Myr, before the disk has been dissipated by stellar winds and radiation.     

一株降解小麦秸秆丝状真菌的筛选、鉴定及初步研究

利用涂布平板法从腐烂秸秆及枯枝烂叶中分离出71株丝状真菌.通过比较菌株秸秆粉降解产物对小麦生长的促进作用,获得一株可有效降解秸秆并促进小麦生长的菌株2-5-2.对其进行形态分析和rRNA序列鉴定,结果显示,该菌株为木霉属真菌.该菌株可产生纤维素酶、木质素酶、半纤维素酶、几丁质酶、蛋白酶、壳聚糖酶.平板对峙培养显示,该菌对多种病原真菌的生长有抑制或阻碍作用.固态发酵培养时,纤维素酶、半纤维素酶酶活在第11d达到最高;第28d,纤维素降解率达到21.13%,半纤维素降解率达到28.53%.     

丝状真菌启动子的基因工程改造进展

丝状真菌是重要的工业酶生产菌,具有优异的蛋白表达和分泌能力,如里氏木霉在工业发酵中其内源纤维素酶产量可高达100g/L。目前,丝状真菌已被成功用于表达外源基因,但与内源基因相比,外源基因的表达效率常常不高。使用强启动子来驱动基因转录可有效提高外源基因的表达水平,因此本文就通过基因工程的方法对丝状真菌的启动子进行改造以提高内、外源基因的转录效率的研究进行总结与展望。     

The essential signature of a massive starburst in a distant quasar

Observations of carbon monoxide emission in high-redshift (zeta > 2) galaxies indicate the presence of large amounts of molecular gas. Many of these galaxies contain an active galactic nucleus powered by accretion of gas onto a supermassive black hole, and a key question is whether their extremely high infrared luminosities result from the active galactic nucleus, from bursts of massive star formation (associated with the molecular gas), or both. In the Milky Way, high-mass stars form in the dense cores of interstellar molecular clouds, where gas densities are n(H2) > 10(5) cm(-3) (refs 1, 2). Recent surveys show that virtually all galactic sites of high-mass star formation have similarly high densities. The bulk of the cloud material traced by CO observations, however, is at a much lower density. For galaxies in the local Universe, the HCN molecule is an effective tracer of high-density molecular gas. Here we report observations of HCN emission from the infrared-luminous 'Cloverleaf' quasar (at a redshift zeta = 2.5579). The HCN line luminosity indicates the presence of 10 billion solar masses of very dense gas, an essential feature of an immense starburst, which contributes, together with the active galactic nucleus it harbours, to its high infrared luminosity.     

膨胀污泥和泡沫中的丝状菌及其控制

本文对活性污泥废水处理中的丝状微生物的形态进行了观察。结果表明,在城市废水处理厂的活性污泥中,引起污泥膨胀的丝状菌主要有Microthrix Parvicella,Nostocoida Limicola,0041,Thiothrix I,0092和Nocardia SP等;泡沫中的丝状菌为M.Parvicella和NocardiaSP.进一步分析了引起污泥膨胀的丝状菌繁殖条件及控制方法。     

Identification of iron sulphide grains in protoplanetary disks

Sulphur is depleted in cold dense molecular clouds with embedded young stellar objects, indicating that most of it probably resides in solid grains. Iron sulphide grains are the main sulphur species in cometary dust particles, but there has been no direct evidence for FeS in astronomical sources, which poses a considerable problem, because sulphur is a cosmically abundant element. Here we report laboratory infrared spectra of FeS grains from primitive meteorites, as well as from pyrrhotite ([Fe, Ni](1-x)S) grains in interplanetary dust, which show a broad FeS feature centred at approximately 23.5 micrometres. A similar broad feature is seen in the infrared spectra of young stellar objects, implying that FeS grains are an important but previously unrecognized component of circumstellar dust. The feature had previously been attributed to FeO. The observed astronomical line strengths are generally consistent with the depletion of sulphur from the gas phase, and with the average Galactic sulphur/silicon abundance ratio. We conclude that the missing sulphur has been found.     

High CO2 levels in the Proterozoic atmosphere estimated from analyses of individual microfossils

Solar luminosity on the early Earth was significantly lower than today. Therefore, solar luminosity models suggest that, in the atmosphere of the early Earth, the concentration of greenhouse gases such as carbon dioxide and methane must have been much higher. However, empirical estimates of Proterozoic levels of atmospheric carbon dioxide concentrations have not hitherto been available. Here we present ion microprobe analyses of the carbon isotopes in individual organic-walled microfossils extracted from a Proterozoic ( approximately 1.4-gigayear-old) shale in North China. Calculated magnitudes of the carbon isotope fractionation in these large, morphologically complex microfossils suggest elevated levels of carbon dioxide in the ancient atmosphere--between 10 and 200 times the present atmospheric level. Our results indicate that carbon dioxide was an important greenhouse gas during periods of lower solar luminosity, probably dominating over methane after the atmosphere and hydrosphere became pervasively oxygenated between 2 and 2.2 gigayears ago.     

The potential of vertebrate microfossils for marine to non-marine correlation in the Late Jurassic

Fish (cartilaginous: elasmobranch and bony: osteichthyan actinopterygian) and reptile (crocodile) microfossils comprising scales and teeth have been examined from a series of limestone samples in the Upper Jurassic of France and Germany to gauge the possibilities of using them for correlation between fully marine and hypo-or hyper-saline (non-marine) deposits.     

Discovery of a bright quasar without a massive host galaxy

A quasar is thought to be powered by the infall of matter onto a supermassive black hole at the centre of a massive galaxy. Because the optical luminosity of quasars exceeds that of their host galaxy, disentangling the two components can be difficult. This led in the 1990s to the controversial claim of the discovery of 'naked' quasars. Since then, the connection between quasars and galaxies has been well established. Here we report the discovery of a quasar lying at the edge of a gas cloud, whose size is comparable to that of a small galaxy, but whose spectrum shows no evidence for stars. The gas in the cloud is excited by the quasar itself. If a host galaxy is present, it is at least six times fainter than would normally be expected for such a bright quasar. The quasar is interacting dynamically with a neighbouring galaxy, whose gas might be feeding the black hole.     

丝状真菌表达系统在thaumatin基因工程中的优化

在thaumatin重组生产中，丝状真菌是最成功的表达系统，十几年来，为了最大程度地获得重组thaumatin，人们对丝状真菌表达系统进行了各种优化，如选用特异性强启动子、增加基因拷贝数、利用蛋白酶缺陷株、进行基因融合、优化反应条件等。随着丝状真菌表达系统的优化，重组thaumatin的产量也随之提高。     

大规模MIMO系统能效优化算法研究综述

随着移动用户数与高速数据业务应用的快速增长,满足下一代网络更高频效和能效需求的大规模多输入多输出(multiple-input multiple-output,MIMO)技术成为5G的研究热点。天线数目的增加,导致大规模MIMO系统的能耗也将急剧增加。优化大规模MIMO系统能效以实现绿色通信成为5G资源管理的一项重要研究课题。针对该问题,对大规模MIMO能效优化算法进行了综述与展望。介绍了大规模MIMO系统能效模型,综述了大规模MIMO系统能效优化算法研究现状,包括基于天线选择的能效优化、基于功率分配的能效优化、频效和能效的折中和多参数联合优化能效;探讨了学术界在大规模MIMO系统能效优化算法上的重要研究成果;总结了当前研究中存在的主要问题,展望了大规模MIMO系统能效优化未来的研究趋势。     

缩合法脱除汽油中噻吩类硫化物的研究

将脱硫剂CD-1与Amberlyst-15酸性树脂配合使用,可以有效的将汽油中的噻吩类硫化物经缩合反应转化为沸点超出汽油流程的产品,从而通过蒸馏的方法脱除。模型汽油缩合法脱硫获得的优化实验条件为：反应温度80℃,反应时间20min,脱硫剂与模型汽油质量剂油比为1∶100,催化剂与模型汽油质量剂油比为1∶10,油品中噻吩硫化物的转化率可达100%。汽油中的碱氮类化合物对Amberlyst-15的催化性能有明显影响,会造成催化剂失活。     

A circumstellar disk associated with a massive protostellar object

The formation process for stars with masses several times that of the Sun is still unclear. The two main theories are mergers of several low-mass young stellar objects, which requires a high stellar density, or mass accretion from circumstellar disks in the same way as low-mass stars are formed, accompanied by outflows during the process of gravitational infall. Although a number of disks have been discovered around low- and intermediate-mass young stellar objects, the presence of disks around massive young stellar objects is still uncertain and the mass of the disk system detected around one such object, M17, is disputed. Here we report near-infrared imaging polarimetry that reveals an outflow/disk system around the Becklin-Neugebauer protostellar object, which has a mass of at least seven solar masses (M(o)). This strongly supports the theory that stars with masses of at least 7M(o) form in the same way as lower mass stars.