检索结果-南通市图书馆

天津农业科学 2001年第3期7卷 24-26页

作者：岳东霞许长蔼陈融张要武天津市农业生物工程研究中心天津300192

研究了不同培养条件对 Alternaria solani培养滤液抗菌活性的影响。结果表明，在 25℃黑暗静止条件下， pH值为 6.0的改良 Czapek 1培养液最有利于抗菌活性物质的产生，最佳培养时间为 28天。

关键词：抗菌活性培养条件茄交链孢培养滤液

On a New Hybrid Estimator for the Central Mean Space

在线全文

学校读者我要写书评

暂无评论

Journal of Systems Science & Complexity 2017年第1期30卷 111-121页

作者： xia Qi dong yuexiao Department of Statistical Science Temple University USA.

Existing estimators of the central mean space are known to have uneven performances across different types of link functions. By combining the strength of the ordinary least squares and the principal Hessian directions, the authors propose a new hybrid estimator that successfully recovers the central mean space for a wide range of link functions. Based on the new hybrid estimator, the authors further study the order determination procedure and the marginal coordinate test. The superior performance of the hybrid estimator over existing methods is demonstrated in extensive simulation studies.

关键词： Marginal coordinate test order determination ordinary least squares principal Hessiandirections sufficient dimension reduction.

在线全文

学校读者我要写书评

暂无评论

剖宫产术后瘢痕妊娠临床分析

中国实用医药 2013年第26期8卷 34-36页

作者：卢萍许传娟赵金慧董月霞张晓慧山东省潍坊医学院附属诸城市人民医院妇科 262200

目的探讨瘢痕妊娠早期诊断和处理。方法回顾性分析2007年5月至2012年8月收治的18例病例资料。结果 9例停经后B超发现瘢痕妊娠,6例于人工流产术中发生大出血,3例人工流产术后少量阴道流血不止。其中4例药物保守治疗成功,6例行病灶切除,8... 详细信息

目的探讨瘢痕妊娠早期诊断和处理。方法回顾性分析2007年5月至2012年8月收治的18例病例资料。结果 9例停经后B超发现瘢痕妊娠,6例于人工流产术中发生大出血,3例人工流产术后少量阴道流血不止。其中4例药物保守治疗成功,6例行病灶切除,8例采用子宫动脉栓塞治疗成功,无子宫切除者。结论子宫动脉栓塞是安全有效的治疗方法。

关键词：剖宫产瘢痕妊娠人工流产子宫动脉栓塞

渤海湾盆地南堡富油气凹陷烃源岩的形成及其特征

在线全文

学校读者我要写书评

暂无评论

天然气地球科学 2007年第1期18卷 78-83页

作者：郑红菊董月霞王旭东张水昌张大江朱光有熊英于海东中国石油勘探开发研究院北京100083 中国石油冀东油田河北唐山063004

渤海湾盆地南堡凹陷近年来油气勘探取得重大发现,已成为该盆地油气富集程度最高的富油气凹陷之一。研究发现:下第三系沙河街组特别是沙三4亚段发育高丰度的优质烃源岩,TOC高达5%以上,由于其形成于南堡凹陷主裂陷幕,此时湖盆水体最深,湖... 详细信息

渤海湾盆地南堡凹陷近年来油气勘探取得重大发现,已成为该盆地油气富集程度最高的富油气凹陷之一。研究发现:下第三系沙河街组特别是沙三4亚段发育高丰度的优质烃源岩,TOC高达5%以上,由于其形成于南堡凹陷主裂陷幕,此时湖盆水体最深,湖盆范围最广,发育大面积深湖相灰色、灰黑色泥岩、钙质泥岩、油页岩,且厚度大,平面上分布稳定,具有巨大的生烃潜力;沙三3亚段的暗色泥岩,生烃潜力较大。指出沙三段烃源岩是南堡凹陷最重要的烃源岩,其生烃量占南堡凹陷70%以上。沙一段烃源岩虽然没有东营组烃源岩厚度大,但是演化程度比东营组烃源岩高,二者生烃量比较接近,分别占南堡凹陷生油量的15%左右。

关键词：优质烃源岩沙河街组沉积演化南堡富油气凹陷渤海湾盆地

Neo I represents a group of transcriptional repressors regulating the biosynthesis of multiple aminoglycosides

在线全文

学校读者我要写书评

暂无评论

Science China Life Sciences 2024年第12期67卷 2761-2770页

作者： yue Li xiangxi Meng dong Li Xiulei xia Jihui Zhang Yihua Chen Huarong Tan State Key Laboratory of Microbial Resources Institute of Microbiology Chinese Academy of Sciences University of Chinese Academy of Sciences

In general, the initiation or closure of antibiotic biosynthesis is determined by regulatory proteins, but most of their mechanisms of action remain unknown. The 2-deoxystreptamine-containing aminoglycosides（2-DOS AGs） form a unique category among antibiotics. Genomic analysis revealed that a group of hypothetical regulatory genes represented by neo I are widely distributed in the biosynthetic gene clusters（BGCs） of natural products from Streptomyces species, including several 2-DOS AGs. Only limited knowledge is available for the roles of Neo Itype regulators although neomycin and some of the related AGs have been developed as therapeutic drugs for decades. This study focuses on the functional determination of neo I and its homologues situated in the BGCs of six AGs. We found that the yield of neomycin in neo I disruption mutant（Δneo I） increased by 50% compared to the wild-type（WT） strain(（420.6±44.1） mg L-1), while it was partially restored by the complementation of neo I, demonstrating that Neo I acted as a repressor in neomycin biosynthesis. Further electrophoretic mobility shift assays（EMSAs） and DNase I footprinting assays indicated that Neo I could specifically bind to the promoter region between neo E and neo I with conserved nucleotides（5'-CVHYMRCHDKAGYGGACR-3'）, as determined by site-directed mutagenesis. Interestingly, cross-bindings of the Neo I homologues from the six different BGCs to their corresponding DNA targets were manifested, and the five exogenous Neo I homologues could complement Neo I function of repressing neomycin biosynthesis. Our results suggested that Neo I-type regulators represent widespread and conservative regulatory characteristics in the biosynthesis of 2-DOS AGs, which would be significant for optimizing the biosynthetic pathways of valuable commercialized aminoglycoside antibiotics.

关键词： aminoglycosides neomycin regulation Streptomyces fradiae

Deep appearance modeling:A survey

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Visual Informatics 2019年第2期3卷 59-68页

作者： yue dong Microsoft Research Asia T2 Microsoft Building5th Danling StreetBeijingChina

Appearance modeling is an essential task in computer graphics for capturing and reproducing rich appearance of real world materials under different lighting and viewing *** recent advances of deep learning techniques,a set of deep learning based approaches have been proposed for improving the efficiency and result quality of appearance *** this paper,we provide a survey of these deep appearance modeling techniques from both graphics and machine learning perspectives,and discuss the challenges and opportunities along this direction.

关键词： Appearance modeling Surface reflectance Reflectance field Light field

Tunable Adsorption and Desorption of Hydrogen Atoms on Single-Walled Carbon Nanotubes

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 2002年第10期19卷 1498-1500页

作者： Zhao Ming-Wen, xia yue-Yuan Department of Physics Shandong University Department of Optoelectronics Shandong University

Chemical adsorption and desorption of hydrogen atoms on single-walled carbon nanotubes (SWNTs) are investigated by using molecular dynamics simulations. It is found that the adsorption and desorption energy of hydrogen atoms depend on the hydrogen coverage and the diameter of the SWNTs. Hydrogen-adsorption geometry at the coverage of 1.0 is more energetically stable. The adsorption energy decreases with the increasing diameter of the armchair tubes. The adsorption and desorption energy of hydrogen atoms can be modified reversibly by externally radial deformation. The averaged C-H bond energy on the high curvature sites of the deformed tube increases with increasing radial deformation, while that on the low curvature sites decreases

关键词： Molecular dynamics

Event-trigger-based consensus secure control of linear multi-agent systems under DoS attacks over multiple transmission channels

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

Science China(Information Sciences) 2020年第5期63卷 105-118页

作者： Yang YANG Yanfei LI dong yue College of Automation & College of Artificial Intelligence Nanjing University of Posts and Telecommunications Jiangsu Engineering Laboratory of Big Data Analysis and Control for Active Distribution Network Nanjing University of Posts and Telecommunications Institute of Advanced Technology Nanjing University of Posts and Telecommunications

This paper proposes a consensus secure control scheme in the presence of denial-of-service(DoS)attacks based on an event-trigger mechanism. In contrast to a scenario in which attacks are the same and simultaneously paralyze all channels, the DoS attack addressed in this paper occurs aperiodically and results in the independent interruption of multiple transmission channels. A sufficient condition for the attack duration is designed and a distributed event-triggered control scheme is proposed, where the updated instants are triggered aperiodically to reduce the required communication resources. It is shown that the overall system is stable with the proposed scheme according to the Lyapunov stability theory and that Zeno behavior is excluded. Finally, a numerical example is presented to verify the effectiveness of the proposed scheme.

关键词： multi-agent system event-triggered control consensus secure control denial-of-service attack multiple transmission channels

Lattice Strain Induced by Ion Implantation in AlGaAs/AlGaInAs Quantum Well Samples

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Chinese Physics Letters 2002年第4期19卷 599-601页

作者： Liu Pi-Jun, xia yue-Yuan Department of Physics Shandong University

Si^+ ions of 350 keV have been implanted into AlGaAs/AlGaInAs quantum well samples in the dose range from 5×10^13cm^-2to 5×10^14cm^-2. The Raman spectra and high resolution x-ray diffraction (HRXRD) were measured from these implanted samples as well as the non-implanted sample. In the implanted layers the average strain which was evaluated by HRXRD increases with the implantation doses and varies from 0.0011 to 0.0029. The quantum well interface intermixing effect and compositional modification are also observed from HRXRD. At the higher doses, an abnormal annealing procedure takes place and it partly removes damage, but the strain remains almost unchanged in the epilayers.

关键词： Aluminum gallium arsenide

INFLUENCE OF SURFACTANT ON TWO-PHASE FLOW REGIME AND PRESSURE DROP IN UPWARD INCLINED PIPES

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

Journal of Hydrodynamics 2012年第1期24卷 39-49页

作者： xia Guo-dong CHAI Lei Key Laboratory of Enhanced Heat Transfer and Energy Conservation Ministry of EducationCollege ofEnvironmental and Encrgy EngineeringBeijing University of TechnologyBeijing 100124China

The influence of a surfactant on the two-phase flow regime and the pressure drop in upward inclined pipes is investigated for various gas/liquid flow *** air/water and air/100 ppm sodium dodecyl sulphate aqueous solution are used as the working *** influence of the surfactant on the two-phase flow regime in upward inclined pipes is investigated using the electrical tomographic *** 0o,2.5o and 5o pipe inclinations,the surfactant has obvious effect on the transition from the stratified wavy flow to the annular flow,and the range of the stratified smooth flow regime is also extended to higher gas *** 10o pipe inclination,no stratified flow regime is observed in the air/water *** the air/surfactant solution system,however,the stratified flow regime can be found in the range of *** all inclination angles,the changes of the pressure gradient characteristics are accompanied with the flow pattern *** surfactant in a two-phase flow would reduce the pressure gradient significantly in the slug flow and annular flow *** the annular flow regime,the pressure gradient gradually becomes free of the influence of the upward inclined angle,and is only dependent on the property of the two-phase flow.

关键词： surfactant flow regime pressure drop two-phase flow