检索结果-南通市图书馆

Isolation and characterization of gasoline-degrading bacteria from gas station leaking-contaminated soils

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2006年第5期18卷 969-972页

作者： LU si-jin WANG Hong-qi YAO Zhi-hua College of Water Sciences Beijing Normal University Beijing 100875 China

The effects of culture conditions in vitro and biosurfactant detection were studied on bacterial strains capable of degrading gasoline from contaminated soils near gas station. The main results were summarized as follows. Three bacteria （strains Q10, Q14 and Q18） that were considered as efficiently degrading strains were isolated and identified as Pseudomonas sp., Flavobaeterium sp. and Rhodococcus sp., respectively. The optimal growth conditions of three bacteria including pH, temperature and the concentration of gasoline were similar. The reduction in surface tension was observed with all the three bacteria, indicating the production of biosurfactant compounds. The value of surface tension reduced by the three strains Q10, Q14 and Q18 was 32.6 mN.m, 12.4 mN. m and 21.9 mN.m, respectively. Strain Q10 could be considered as a potential biosurfactant producer. Gasoline, diesel oil, benzene, toluene, ethylbenzene and xylene （BTEX） could easily be degraded by the three isolates. The consortium was more effective than the individual cultures in degrading added gasoline, diesel oil, and BTEX. These results indicate that these strains have great potential for in situ remediation of soils contaminated by gas station leaking.

关键词： gasolene BTEX bacteria biosurfactant consortium

Analysis of limit cycle oscillations of a typical airfoil section with freeplay

在线全文

学校读者我要写书评

暂无评论

Acta Mechanica sinica 2013年第4期29卷 583-592页

作者： si-jin Zhang Gui-Lin Wen Fan Peng Zi-Qiang Liu School of Mechanical and Vehicle Engineering Hunan University Institute of Astronautic Aero-Dynamics and Technology

A typical airfoil section system with freeplay is investigated in the paper. The classic quasi-steady flow model is applied to calculate the aerodynamics, and a piecewise-stiffness model is adopted to characterize the non- linearity of the airfoil section＇s freeplay. There are two crit- ical speeds in the system, i.e., a lower critical speed, above which the system might generate limit cycle oscillation, and an upper critical one, above which the system will flutter. Then a Poincar6 map is constructed for the limit cycle os- cillations by using piecewise-linear solutions with and with- out contact in the system. Through analysis of the Poincar6 map, a series of equations which can determine the frequen- cies of period-1 limit cycle oscillations at any flight veloc- ity are derived. Finally, these analytic results are compared to the results of numerical simulations, and a good agree- ment is found. The effects of freeplay value and contact stiffness ratio on the limit cycle oscillation are also analyzed through numerical simulations of the original system. More- over, there exist multi-periods limit cycle oscillations and even complicated ＂chaotic＂ oscillations may occur, which are usually found in smooth nonlinear dynamic systems.

关键词： Freeplay nonlinearity ~ Typical airfoil section ~Limit cycle oscillations ~ Poincar6 map

EDTA-enhanced phytoremediation of lead contaminated soil by Bidens maximowicziana

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2007年第12期19卷 1496-1499页

作者： WANG Hong-qi LU si-jin LI hua YAO Zhi-hua College of Water Sciences Beijing Normal University Beijing 100875 China.

Phytoremediation is a potential cleanup technology for the removal of heavy metals from contaminated soils. Bidens is a new Pb hyperaccumulator, which not only has remarkable tolerance to Pb but also extraordinary accumulation capacity for Pb. The maximum Pb concentration was 1509.3 mg/kg in roots and 2164.7 mg/kg in overground tissues. The Pb distribution order in the B. was： leaf 〉 stem 〉 root. The effect of amendments on phytoremediation was also studied. The mobility of soil Pb and the Pb concentrations in plants were both increased by EDTA application. Compared with CK （control check）, EDTA application promoted translocation of Pb to overground parts of the plant. The Pb concentrations in overground parts of plants was increased from 24.23-680.56 mg/kg to 29.07-1905.57 mg/kg. This research demonstrated that B. maximowicziana appeared to be suitable for phytoremediation of Pb contaminated soil, especially, combination with EDTA.

关键词： phytoremediation Bidens maximowicziana lead amendment EDTA

Contrasting physical properties of the trilayer nickelates Nd4Ni3O10 and Nd4Ni3O8

在线全文

学校读者我要写书评

暂无评论

Science China(Physics,Mechanics & Astronomy) 2021年第2期64卷 98-104页

作者： Qing Li ChengPing He XiYu Zhu jin si XinWei Fan Hai-Hu Wen Center for Superconducting Physics and Materials National Laboratory of Solid State Microstructures and Department of PhysicsCollaborative Innovation Center of Advanced MicrostructuresNanjing UniversityNanjing210093China

We report the crystal structures and physical properties of trilayer nickelates Nd4Ni3O10and *** of magnetization and electrical resistivity display contrasting behaviors in the two ***4Ni3O10shows a paramagnetic metallic behavior with a metal-to-metal phase transition(T^*)at about 162 K,as revealed by both magnetic susceptibility and *** magnetoresistance and Hall coefficient results show a negative magnetoresistance at low temperatures and the carrier type of Nd4Ni3O10is dominated by hole-type charge *** significant enhancement of Hall coefficient and resistivity below T*suggests that effective charge carrier density decreases when cooling through the transition *** contrast,Nd4Ni3O8 shows an insulating *** addition,this compound shows a paramagnetic behavior with the similar magnetic moment as that of Nd4Ni3O10derived from the Curie-Weiss *** may suggest that the magnetic moments in both systems are contributed by Nd^3+ *** applying pressures up to about 49 GPa,the insulating behavior is still present and becomes even stronger under a high *** results suggest that the different Ni configurations(Ni^1+/2+ or Ni^2+/3+)and the changes of coordination environment of Ni sites may account for the contrasting behaviors in trilayer nickelates Nd4Ni3O10and Nd4Ni3O8.

关键词： trilayer nickelate Nd4Ni3O10 and Nd4Ni3O8 high-pressure study

Case Report:Congenital spinal intradural arachnoid cyst associated with intrathoracic meningocele in a child

在线全文

学校读者我要写书评

暂无评论

Journal of Zhejiang University-Science B(Biomedicine & Biotechnology) 2010年第6期11卷 429-432页

作者： Zheng-xi RAO jin LI si-qing HANG Chao YOU Department of Neurosurgery West China Hospital Siehuan University Chengdu 610041 China

Congenital spinal intradural arachnoid cyst associated with intrathoracic meningocele is very *** report a case in a 9-year-old Chinese boy who presented with a two-week history of progressive paraparesis and gait *** resonance imaging revealed that a dorsal intradural extramedullary cystic lesion extended from T1 to T5 and compressed the spinal cord.A left lateral intrathoracic meningocele pouch was found incidentally at the level of *** arachnoid cyst as well as meningocele was removed and the spinal cord compression was *** cyst was confirmed by histological *** patient recovered well *** is the second report of such a case in the world according to the available *** take-home message for our case is that the surgical approach should be individualized,depending on the size and location.

关键词： Spinal intradural arachnoid cyst Intrathoracic meningocele Spinal cord compression Surgical treatment

Systematic identification and annotation of multiple-variant compound effects at transcription factor binding sites in human genome

在线全文

学校读者我要写书评

暂无评论

Journal of Genetics and Genomics 2018年第7期45卷 373-379页

作者： si-jin Cheng Shuai Jiang Fang-Yuan Shi Yang Ding Ge Gao State Key Laboratory of Protein and Plant Gene Research School of Life SciencesCenter for BioinformaticsPeking University Beijing Advanced Innovation Center for Genomics Peking University

Understanding the functional effects of genetic variants is crucial in modern genomics and genetics. Transcription factor binding sites （TFBSs） are one of the most important cis-regulatory elements. While multiple tools have been developed to assess functional effects of genetic variants at TFBSs, they usually assume that each variant works in isolation and neglect the potential ＂interference＂ among multiple variants within the same TFBS. In this study, we presented COPE-TFBS （Context-Oriented Predictor for variant Effect on Transcription Factor Binding site）, a novel method that considers sequence context to accurately predict variant effects on TFBSs. We systematically re-analyzed the sequencing data from both the 1000 Genomes Project and the Genotype-Tissue Expression （GTEx） Project via COPE-TFBS, and identified numbers of novel TFBSs, transformed TFBSs and discordantly annotated TFBSs resulting from multiple variants, further highlighting the necessity of sequence context in accurately annotating genetic variants.

关键词： Compound effect Transcription factor binding site Variant annotation Bioinformatics Genetic variants

The Influence of Coherent Transient Energy Transfer on Femtosecond Time-Resolved Z-Scan Measurements

在线全文

学校读者我要写书评

暂无评论

Chinese Physics Letters 2012年第10期29卷 77-80页

作者： CHEN Tao si jin-Hai LIU Xiang CHEN Feng HOU Xun Key Laboratory for Physical Electronics and Devices of the Ministry of Education&Shaanxi Key Lab of Information Photonic Technique School of Electronic&Information EngineeringXi'an Jiaotong UniversityXi'an 710049

We investigate the influence of the coherent effect on femtosecond time-resolved Z-scan measurements using a degenerate pump-probe Z-scan *** time response of the light-induced transient grating(LITG)of Bi_(2)O_(3)-B_(2)O_(3)-siO_(2)(BI)glass shows a valley-peak variation,which has an obvious influence on the time-resolved Z-scan *** valley-peak variation of the LITG signals with the delay time in BI glass is due to coherent transient energy transfer between positively chirped pump and probe *** influence of the LITG effect on the closed-aperture time-resolved Z-scan measurements could be reduced by adjusting the position of the aperture transversely.

关键词： technique pump Femto

Fabrication of Micro-Grooves in silicon Carbide Using Femtosecond Laser Irradiation and Acid Etching

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Physics Letters 2014年第3期31卷 169-172页

作者： KHUAT Vanthanh MA Yun-Can si jin-Hai CHEN Tao CHEN Feng HOU Xun Key Laboratory for Physical Electronics and Devices of the Ministry of Education and Shaanxi Key Lab of Information Photonic Technique School of Electronics and information Engineering Xi'an Jiaotong University Xi'an 710049 Le Quy Don Technical University Hanoi 7EN-248 Vietnam

A simple method using an 800-nm femtosecond laser and chemical selective etching is developed for fabrication of high-aspect-ratio grooves in silicon carbide. Micro grooves with an aspect ratio of approximately 40 are obtained. The morphology and chemical compositions of the grooves are analyzed using a scanning electronic microscope equipped with an energy dispersive x-ray spectroscopy. The formation mechanism of siC grooves is attributed to the chemical reactions of the laser induced structural changes with a mixed solution of hydrofluoric acid and nitric acid. In addition, the effects of laser irradiation parameters on the aspect ratio of the grooves are investigated.

关键词： siLICON carbide RESEARCH FEMTOSECOND lasers -- Research IRRADIATION MICROELECTROMECHANICAL systems PHYsiCS research

Large Non-resonant Nonlinear Optical Susceptibility of Cu_(2)O Microcrystallites

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Physics Letters 1996年第3期13卷 182-184页

作者： WANG You-gui si jin-hai ZHAO Jiang ZOU Bing-suo YE Pei-xian Institute of Physics Chinese Academy of SciencesBeijing 100080

We report the measured results of non-resonant nonlinearity by degenerate four-wave mixing for Cu2O nanopartides having central diameter of 9 *** value of x^(3) obtained in a 10ns pulse experiment is 8.48×1O^(-10) es... 详细信息

关键词： resonant nonlinearity Nonlinear