Bioremediation of Cd by Microbially Induced Calcite Precipitation

Contamination by Cd is a significant environmental problem. Therefore, we examined Cd removal from an environmental perspective. Ureolysis-driven calcium carbonate precipitation has been proposed for use in geotechnical engineering for soil remediation applications. In this study, 55 calcite-forming bacterial strains were newly isolated from various environments. Biomineralization of Cd by calcite-forming bacteria was investigated in laboratory-scale experiments. A simple method was developed to determine the effectiveness of microbially induced calcite precipitation (MICP). Using this method, we determined the effectiveness of biomineralization for retarding the flow of crystal violet through a 25-mL column. When the selected bacteria were analyzed using an inductively coupled plasma optical emission spectrometer, high removal rates (99.95 %) of Cd were observed following incubation for 48 h. Samples of solids that formed in the reaction vessels were examined using a scanning electron microscope. The CdCO₃ compounds primarily showed a spherical shape. The results of this study demonstrate that MICP-based sequestration of soluble heavy metals via coprecipitation with calcite may be useful for toxic heavy metal bioremediation.     

Synthesis and magnetic properties of CdS/α-Fe_2O_3 hierarchical nanostructures

CdS/α-Fe2O3 hierarchical nanostructures, where the CdS nanorods grow irregularly on the side surface of α-Fe2O3 nanorods, were synthesized via a three-step process. The diameters and lengths of CdS nanorods can be tuned by changing the ethylenediamine (EDA) and Cd ion concentrations. The magnetic investigations by superconducting quantum interference device indicate that the hierarchical nanostructures have an Morin transition at lower temperature (230 K) than that of the single bulk α-Fe2O3 materials (263 ...     

浅谈AOI系统在SMT生产线的应用实施

本文简要分析了SMT生产线上常用的检测方法,着重介绍先,进的全自动光学检测(AOI)技术及其优点,并提出配合SMT柔性生产模式的应用实施.最后重点介绍风华高科VPD系列在线式全自动光学检测机的功能.     

IGRS(闪联)概述

简要介绍了目前国内外有关信息设备互联的技术和业界标准，重点概述信产部最近批准发布的信息设备间智能组网。资源共享标准——闪联（IGRS）标准的技术目标和技术特点。并介绍了闪联标准产业化进展情况。     

Preparation of silica nanowires using porous silicon as Si source

This very paper is focusing on the preparation of silica nano-wires via annealing porous silicon wafer at 1200 °C in H₂ atmosphere and without the assistant metal catalysts. X-ray diffraction, X-ray energy dispersion spectroscopy, scanning electron microscopy, high-resolution transmission electron microscopy and selected area diffraction technology have been employed for characterizing the structures, the morphology and the chemical components of the nano-wires prepared, respectively. It is found that the diameter and the length of the nano-wires were about 100 nm and tens micron, respectively. Meanwhile, it is also necessary to be pointed out that silica NWs only formed in the cracks of porous wafers, where the stress induced both by the electro-chemical etching procedure for the porous silicon preparation and nanowires growth procedure is believed to be lower than that at the center of the island. Therefore, a stress-driven mechanism for the NWs growth model is proposed to explain these findings.     

MySQL数据库在嵌入式Linux平台上的移植和应用

MySQL数据库和嵌入式系统的应用十分广泛,但是关于嵌入式系统中数据库方面的研究尚为数不多.通过对MySQL数据库源代码和编译步骤的修改,可以将其移植到嵌入式Linux平台上.移植完成后,使用C语言接口函数编写应用程序便可登录远程数据库并进行查询和修改等操作.将MySQL数据库与MiniGUI图形界面相结合,可以使对数...     

Synthesis and magnetic properties of CdS/α-Fe<Subscript>2</Subscript>O<Subscript>3</Subscript> hierarchical nanostructures

CdS/α-Fe₂O₃ hierarchical nanostructures, where the CdS nanorods grow irregularly on the side surface of α-Fe₂O₃ nanorods, were synthesized via a three-step process. The diameters and lengths of CdS nanorods can be tuned by changing the ethylenediamine (EDA) and Cd ion concentrations. The magnetic investigations by superconducting quantum interference device indicate that the hierarchical nanostructures have an Morin transition at lower temperature (230 K) than that of the single bulk α-Fe₂O₃ materials (263 K). Importantly, the hierarchical nanostructures exhibit weakly ferromagnetic characteristics at 300 K. A sharp peak assigned to the surface trap induced emission are observed in room temperature PL spectra. Combining with the optoelectronic properties of CdS, the CdS/α-Fe₂O₃ hierarchical nanostructures may be used as multi-functional materials for optoelectronic and magnetic devices. Supported by the National Natural Science Foundation of China (Grant Nos. 50772025 and 50872159), the Ministry of Science and Technology of China (Grant No. 2008DFR20420), the China Postdoctoral Science Foundation (Grant Nos. 20060400042 and 200801044), the Natural Science Foundation of Heilongjiang Province, China (Grant No. F200828), the Specialized Research Fund for the Doctoral Program of Higher Education of China (Grant No. 20070217002), and the Innovation Foundation of Harbin City (Grant No. RC2006QN017016)     

Solvent and catalyst free azo-Michael addition under high-speed vibration milling

Under the high-speed vibration milling conditions,the solvent and catalyst-free azo-Michael addition of chalcone derivatives and amines was found to proceed efficiently in excellent yields at ambient temperature in short reaction time.In most cases,conventional side reactions were avoided and thus quantitative yields were achieved.The influences of the vibration frequency and reaction time on the azo-Michael addition were investigated.     

片式元件编带用全自动卷带机的研究与开发

全自动卷带机是高速编带机的配套设备,它通过与编带机共享信息,使编带的全过程真正做到了高速自动化.本文针对全自动卷带机的主要特点介绍了设备的总体研制以及应用,并分析了卷带机的潜在市场.     

Bioremediation of Cd by Microbially Induced Calcite Precipitation

Contamination by Cd is a significant environmental problem. Therefore, we examined Cd removal from an environmental perspective. Ureolysis-driven calcium carbonate precipitation has been proposed for use in geotechnical engineering for soil remediation applications. In this study, 55 calcite-forming bacterial strains were newly isolated from various environments. Biomineralization of Cd by calcite-forming bacteria was investigated in laboratory-scale experiments. A simple method was developed to determine the effectiveness of microbially induced calcite precipitation (MICP). Using this method, we determined the effectiveness of biomineralization for retarding the flow of crystal violet through a 25-mL column. When the selected bacteria were analyzed using an inductively coupled plasma optical emission spectrometer, high removal rates (99.95 %) of Cd were observed following incubation for 48 h. Samples of solids that formed in the reaction vessels were examined using a scanning electron microscope. The CdCO₃ compounds primarily showed a spherical shape. The results of this study demonstrate that MICP-based sequestration of soluble heavy metals via coprecipitation with calcite may be useful for toxic heavy metal bioremediation.