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一种分子量标准的引物定位合成 被引量:1
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作者 崔映宇 范海燕 《阜阳师范学院学报(自然科学版)》 2000年第1期8-10,19,共4页
分子量标准引物定位合成(Marker Primer-directed Synthesis,简称MPDS)乃一种DNA碱基对梯度片段的简易合成术。该方法用两套不同的引物进行靶DNA的PCR扩增。一套为范围引物,决定每一梯度片段的绝对长度;另一套为间隔引物,决定两个梯度... 分子量标准引物定位合成(Marker Primer-directed Synthesis,简称MPDS)乃一种DNA碱基对梯度片段的简易合成术。该方法用两套不同的引物进行靶DNA的PCR扩增。一套为范围引物,决定每一梯度片段的绝对长度;另一套为间隔引物,决定两个梯度片段之间的大小差异。用这种技术得到的梯度片段,可用作分析DNA片段大小的分子量标准。目前已用此方法成功地合成了90~204bp范围内以6bp为梯度的分子量标准,对在经溴乙锭或硝酸银染色的聚丙烯酰胺凝胶上进行微卫星的分型特别有用。 展开更多
关键词 分子量标准引物 定位合成 DNA PCR 范围引物
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用幅度矢量合成定位法改进HRTF的定位效果 被引量:1
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作者 黄帆 李晓峰 《电声技术》 2007年第1期36-38,共3页
为了改进虚拟3D立体声技术的定位准确性,依据头相关传递函数(HRTF)的原理,采用CIPIC实验室根据KEMAR假人头测得的HRTF数据,利用多媒体计算机合成了两通道虚拟3D立体声。通过对HRTF在声源前后定位的“混淆锥”问题的分析,提出了用幅度矢... 为了改进虚拟3D立体声技术的定位准确性,依据头相关传递函数(HRTF)的原理,采用CIPIC实验室根据KEMAR假人头测得的HRTF数据,利用多媒体计算机合成了两通道虚拟3D立体声。通过对HRTF在声源前后定位的“混淆锥”问题的分析,提出了用幅度矢量合成定位(VBAP)方法改进定位效果。实验结果证明,使用VBAP改进后的HRTF能够显著提高声源前后定位的准确性,表明VBAP的声音加权能够对HRTF的混淆锥问题有较大改进。 展开更多
关键词 头相关传递函数 幅度矢量合成定位 混淆锥
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合成孔径无源定位性能分析与参数设计
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作者 王裕旗 孙光才 +1 位作者 邢孟道 张子敬 《电子与信息学报》 EI CSCD 北大核心 2022年第9期3155-3162,共8页
合成孔径无源定位中,为获得高的2维分辨率,需要长的合成孔径,但斜距历程的多项式近似会带来距离定位的误差。针对此问题,该文分析了合成孔径定位中距离误差的影响因素,给出了定位误差的近似表达式,同时分析了距离和方位分辨率的影响因素... 合成孔径无源定位中,为获得高的2维分辨率,需要长的合成孔径,但斜距历程的多项式近似会带来距离定位的误差。针对此问题,该文分析了合成孔径定位中距离误差的影响因素,给出了定位误差的近似表达式,同时分析了距离和方位分辨率的影响因素,给出了分辨率的分析方法。在此基础上,综合考虑定位精度和分辨率的约束条件,给出了合成孔径长度参数的优化方法。仿真结果验证了方法的有效性。 展开更多
关键词 无源定位 合成孔径定位 距离定位误差分析 定位分辨率分析 参数优化
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磁性纸印刷适性 被引量:5
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作者 杨欣 龙柱 李海峰 《包装工程》 CAS CSCD 北大核心 2007年第12期91-92,137,共3页
简要介绍了磁性纸的3种制备方法:定位合成法、细胞腔加填法和涂布法,并分别从定量、厚度、平滑度、表面强度、抗张强度、耐折度等物理性能和白度、光泽度等光学性能以及保存条件等方面,比较了这3种方法制备的磁性纸的印刷适性。同时就... 简要介绍了磁性纸的3种制备方法:定位合成法、细胞腔加填法和涂布法,并分别从定量、厚度、平滑度、表面强度、抗张强度、耐折度等物理性能和白度、光泽度等光学性能以及保存条件等方面,比较了这3种方法制备的磁性纸的印刷适性。同时就不同方法制得的磁性纸的合适应用领域进行了初步建议。 展开更多
关键词 磁性纸 定位合成 细胞腔加填法 涂布法 印刷适性
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酿酒酵母细胞器区室化合成化学品的研究进展 被引量:1
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作者 栾韬 尹梦琦 +3 位作者 王明 康秀龙 赵建志 鲍晓明 《生物工程学报》 CAS CSCD 北大核心 2023年第6期2334-2358,共25页
公认食品安全的酿酒酵母(Saccharomyces cerevisiae)是合成生物学中被广泛研究的底盘细胞,常作为生产高值或大宗化学品的微生物细胞工厂。近年来,通过各种代谢工程改造策略,已有大量化学品的合成途径在酿酒酵母中建立并优化,且部分化学... 公认食品安全的酿酒酵母(Saccharomyces cerevisiae)是合成生物学中被广泛研究的底盘细胞,常作为生产高值或大宗化学品的微生物细胞工厂。近年来,通过各种代谢工程改造策略,已有大量化学品的合成途径在酿酒酵母中建立并优化,且部分化学品具备了产业化价值。作为真核生物,酿酒酵母具有完整的细胞内膜系统及其组成的复杂细胞器区室,而这些细胞器区室往往含有某些化学品合成所必需的较高浓度前体底物(如线粒体中的乙酰辅酶A),或更加充足的酶、辅因子、能量等,可为目标产物的生物合成提供更适宜的物理、化学环境,但同时不同细胞器的结构特点有时也成为特定化合物合成的障碍。为此,研究人员在深入分析不同细胞器自身特点的基础上,结合目标化学品合成途径与细胞器之间的适配度,对细胞器开展了大量针对性改造工作以提高产物合成效率。本文详细综述了酿酒酵母中线粒体、过氧化物酶体、高尔基体、内质网、脂滴和液泡等细胞器的途径改造及优化策略,以及利用细胞器区室化合成化学品的研究进展,并对目前存在的困难和挑战以及未来研究方向进行了总结与展望。 展开更多
关键词 生物合成 定位合成 细胞器 代谢工程 底盘细胞 酿酒酵母
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磁性纤维的开发与应用
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作者 汪多仁 《精细化工原料及中间体》 2004年第2期31-32,共2页
磁性纤维制造成本低、工艺简便、切实可行。其以超顺磁性为主略带铁磁性,纤维中磁性微粒小,属纳米级复合材料。
关键词 磁性纤维 理化性能 有机金属络合物分解法 共混纺丝法 表面涂层法 定位合成
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Quantification of photosynthetic inorganic carbon utilisation via a bidirectional stable carbon isotope tracer 被引量:7
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作者 Hongtao Hang Yanyou WU 《Acta Geochimica》 EI CAS CSCD 2016年第2期130-147,共18页
The amount of bicarbonate utilised by plants is usually ignored because of limited measurement methods. Accordingly, this study quantified the photosynthetic assimilation of inorganic carbon (COe and HCO3-) by plant... The amount of bicarbonate utilised by plants is usually ignored because of limited measurement methods. Accordingly, this study quantified the photosynthetic assimilation of inorganic carbon (COe and HCO3-) by plants. The net photosynthetic COa assimilation (PN), the photosynthetic assimilation of CO2 and bicarbonate (PN'), the proportion of increased leaf area (lEA) and the stable carbon isotope composition (δ13C) of Orychophragmus violaceus (Ov) and Brassica juncea (B j) under three bicarbonate levels (5, 10 and 15 mm NaHCO3) were examined to determine the relationship among PN, PN' and fLA. PN', not PN, changed synchronously with fLA. Moreover, the proportions of exogenous bicarbonate and total bicarbonate (including exogenous bicarbonate and dissolved CO2-generated bicarbonate) utilised by Ov were 2.27 % and 5.28 % at 5 mm bicarbonate, 7.06 % and 13.28 % at 10 mm bicarbonate, and 8.55 % and 17.31% at 15 mm bicarbonate, respectively. Meanwhile, the propor- tions of exogenous bicarbonate and total bicarbonate uti- lised by Bj were 1.77 % and 3.28 % at 5 mm bicarbonate, 2.11% and 3.10 % at 10 mm bicarbonate, and 2.36 % and 3.09 % at 15 mm bicarbonate, respectively. Therefore, the dissolved CO2-generated bicarbonate and exogenous bicarbonate are important sources of inorganic carbon for plants. 展开更多
关键词 KARST Bicarbonate - Photosynthesis -Inorganic carbonic utilization Stable carbon isotopecomposition
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Structural Synthesis and Workspaces of Serial Robotic Chains with 7 Axes
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《Journal of Mechanics Engineering and Automation》 2014年第1期35-39,共5页
Redundant serial robot kinematic chains with seven axes are an extension of classical 6-axis ones. The structural synthesis of these structures is useful to provide a working basis, including for the promotion of new ... Redundant serial robot kinematic chains with seven axes are an extension of classical 6-axis ones. The structural synthesis of these structures is useful to provide a working basis, including for the promotion of new structures with 7 axes, besides some already existing and applied structures. This paper summarizes kinematic chain structures using a combinatorial method by listing all possible variants of the structures with 7 axes, obtained by adding a rotational or translational coupling, in a parallel or perpendicular position, against the guiding structure with 6 axes consisting of two distinct modules: positioning module (3 axes) and orientation module (3 axes). Representation of proper workspaces can help the designer in choosing the structure with maximum functionality for a given application. 展开更多
关键词 ROBOT structural synthesis redundant kinematic chain workspace.
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Coseismic slip distribution of 2009 L'Aquila earthquake derived from InSAR and GPS data 被引量:3
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作者 WANG Yong-zhe ZHU Jian-jun +2 位作者 OU Zi-qiang LI Zhi-wei XING Xue-min 《Journal of Central South University》 SCIE EI CAS 2012年第1期244-251,共8页
To better understand the mechanism of the Mw6.3 L'Aquila (Central Italy) earthquake occurred in 2009, global positioning system (GPS) and interferometric synthetic aperture radar (InSAR) data were used to deriv... To better understand the mechanism of the Mw6.3 L'Aquila (Central Italy) earthquake occurred in 2009, global positioning system (GPS) and interferometric synthetic aperture radar (InSAR) data were used to derive the coseismic slip distribution of the earthquake fault. Firstly, based on the homogeneous elastic half-space model, the fault geometric parameters were solved by the genetic algorithm. The best fitting model shows that the fault is a 13.7 km×14.1 km rectangular fault, in 139.3° strike direction and 50.2° southwest-dipping. Secondly, fixing the optimal fault geometric parameters, the fault plane was extended and discretized into 16× 16 patches, each with a size of 1 kmx 1 krn, and the non-uniform slip distribution of the fault was inverted by the steepest descent method with an appropriate smoothing ratio based on the layered crustal structure model. The preferred solution shows that the fault is mainly a normal fault with slight right-lateral strike slip, the maximum slip of 1.01 m is located in the depth of 8.28 km, the average rake is -100.9°, and the total geodetic moment is about 3.34× 1018 N.m (Mw 6.28). The results are much closer than previous studies in comparison with the seismological estimation. These demonstrate that the coseismic fault slip distribution of the L'Aauila earthauake inverted by the crustal model considering layered characters is reliable. 展开更多
关键词 L'Aquila earthquake interferometric synthetic aperture radar global positioning system (GPS) slip distribution
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A Low Power Dissipation Wide-Band CMOS Frequency Synthesizer for a Dual-Band GPS Receiver
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作者 贾海珑 任彤 +3 位作者 林敏 陈方雄 石寅 代伐 《Journal of Semiconductors》 EI CAS CSCD 北大核心 2008年第10期1968-1973,共6页
This paper presents a wide tuning range CMOS frequency synthesizer for a dual-band GPS receiver,which has been fabricated in a standard 0.18μm RF CMOS process. With a high Q on-chip inductor, the wide-band VCO shows ... This paper presents a wide tuning range CMOS frequency synthesizer for a dual-band GPS receiver,which has been fabricated in a standard 0.18μm RF CMOS process. With a high Q on-chip inductor, the wide-band VCO shows a tuning range from 2 to 3.6GHz to cover 2.45 and 3.14GHz in case of process corner or temperature variation,with a current consumption varying accordingly from 0.8 to 0.4mA,from a 1.8V supply voltage. Measurement results show that the whole frequency synthesizer consumes very low power of 5.6mW working at L1 band with in-band phase noise less than - 82dBc/Hz and out-of-band phase noise about - ll2dBc/Hz at 1MHz offset from a 3. 142GHz carrier. The performance of the frequency synthesizer meets the requirements of GPS applications very well. 展开更多
关键词 PLL GPS frequency synthesizer VCO low power CMOS RF
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