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Grafting Propagation Techniques of Red Sandalwood ( Pterocarpus santalinus ), a Precious Hongmu Tree Species 预览
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作者 Xiaonan HUANG Yanming LI +5 位作者 Yiqing LI Tingting LIU Siting CHEN Chengxiang XU Yingshan QIU Yesheng LIANG 《亚洲农业研究:英文版》 2019年第7期71-75,共5页
[Objectives] This article aimed to study the grafting propagation techniques of red sandalwood ( Pterocarpus santalinus ), so as to provide technical support for the effective propagation of seedlings of this precious... [Objectives] This article aimed to study the grafting propagation techniques of red sandalwood ( Pterocarpus santalinus ), so as to provide technical support for the effective propagation of seedlings of this precious Hongmu species.[Methods] Based on the analysis and comparison of the growth performance of the Hongmu tree species introduced to China, taking 1 to 2-year-old Pterocarpus indicus seedlings as rootstocks and single-bud stems of P. santalinus as scions, grafting was carried out from January to April using three grafting propagation methods, cut grafting propagation, skin grafting propagation and oblique grafting propagation.[Results] The results of several years of experiments show that in early spring, P. santalinus could be propagated well using the grafting propagation methods of skin grafting propagation and oblique grafting propagation, with survival rate over 80%. For rootstocks with young age or thin stems, the joint unions of the oblique grafting propagation healed well, without apparent protrusions, unlike those of skin grafting propagation. The survival rate of oblique grafting propagation that is fast and reliable was higher than that of cut grafting propagation.[Conclusions] It is feasible to use the grafting propagation methods to propagate P. santalinus seedlings. This is a traditional and innovative technology path in the propagation of high-quality seedlings of precious Hongmu trees, and can be promoted and applied in industrial practice. 展开更多
关键词 Pterocarpus santalinus GRAFTING OBLIQUE GRAFTING PROPAGATION CUT GRAFTING PROPAGATION Skin GRAFTING PROPAGATION
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Terahertz wave generation from ring-Airy beam induced plasmas and remote detection by terahertz-radiation- enhanced-emission-of-fluorescence: a review
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作者 Kang LIU Pingjie HUANG Xi-Cheng ZHANG 《中国光电子学前沿:英文版》 EI CSCD 2019年第2期117-147,共31页
With the increasing demands for remote spectroscopy in many fields ranging from homeland security to environmental monitoring, terahertz (THz) spectroscopy has drawn a significant amount of attention because of its ca... With the increasing demands for remote spectroscopy in many fields ranging from homeland security to environmental monitoring, terahertz (THz) spectroscopy has drawn a significant amount of attention because of its capability to acquire chemical spectral signatures non-invasively. However, advanced THz remote sensing techniques are obstructed by quite a few factors, such as THz waves being strongly absorbed by water vapor in the ambient air, difficulty to generate intense broadband coherent THz source remotely, and hard to transmit THz waveform information remotely without losing the signal to noise ratio, etc. In this review, after introducing different THz air-photonics techniques to overcome the difficulties of THz remote sensing, we focus mainly on theoretical and experimental methods to improve THz generation and detection performance for the purpose of remote sensing through tailoring the generation and detection media, air-plasma. For the THz generation part, auto-focusing ring-Airy beam was introduced to enhance the THz wave generation yield from two-color laser induced air plasma. By artificially modulated exotic wave packets, it is exhibited that abruptly auto-focusing beam induced air-plasma can give an up to 5.3-time-enhanced THz wave pulse energy compared to normal Gaussian beam induced plasma under the same conditions. At the same time, a red shift on the THz emission spectrum is also observed. A simulation using an interference model to qualitatively describe these behaviors has be developed. For the THz detection part, the results of THz remote sensing at 30 m using THz-radiation-enhanced-emission- of-fluorescence (THz-REEF) technique are demonstrated, which greatly improved from the 10 m demonstration last reported. The THz-REEF technique in the counter-propagation geometry was explored, which is proved to be more practical for stand-off detections than co-propagation geometry. We found that in the counter- propagating geometry the maximum amplitude of the REEF signal is comparable to that in the 展开更多
关键词 ultrafast TERAHERTZ (THz) techniques THZ air- photonics ring-Airy beams THz-radiation-enhanced-emis- sion-of-fluorescence (THz-REEF) of air-plasma in co- propagation geometry THz-REEF of air-plasma in coun-ter-propagation geometry
广东珠玑古巷文化旅游符号传播提升研究 预览
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作者 李贵清 邓漫英 +1 位作者 王玉珊 隋春花 《边疆经济与文化》 2019年第1期67-72,共6页
通过调查问卷对珠玑古巷文化旅游符号当地居民和游客的认知度进行调查,利用SPSS软件对所得数据进行分析,确定珠玑古巷最具代表性的十大文化旅游符号,针对珠玑古巷文化旅游符号传播存在的问题,提出完善珠玑古巷文化旅游符号传播系统、建... 通过调查问卷对珠玑古巷文化旅游符号当地居民和游客的认知度进行调查,利用SPSS软件对所得数据进行分析,确定珠玑古巷最具代表性的十大文化旅游符号,针对珠玑古巷文化旅游符号传播存在的问题,提出完善珠玑古巷文化旅游符号传播系统、建立官方符号传播平台、丰富符号传播方式、优化旅游符号空间建设等传播提升建议。 展开更多
关键词 珠玑古巷 古村落 文化旅游符号 传播
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青藏高原东北部一次罕见强对流天气的中小尺度系统特征分析 被引量:1
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作者 朱平 俞小鼎 《高原气象》 CSCD 北大核心 2019年第1期1-13,共13页
2016年8月17-18日青藏高原东北部出现了罕见的大冰雹、短时暴雨、雷暴大风等强对流天气。运用常规观测资料、NCEP再分析资料、葵花静止气象卫星、多普勒天气雷达等观测资料分析了此次强对流过程的大气环境场和中小尺度对流系统的发生发... 2016年8月17-18日青藏高原东北部出现了罕见的大冰雹、短时暴雨、雷暴大风等强对流天气。运用常规观测资料、NCEP再分析资料、葵花静止气象卫星、多普勒天气雷达等观测资料分析了此次强对流过程的大气环境场和中小尺度对流系统的发生发展和对流传播机制。结果表明:西太平洋副热带高压北抬明显,属于低层暖平流强迫型。水汽输送主要来自南海。维持较长时间的弱冷锋是强对流的地面触发机制;对流云团逐渐演变为MCC,对流传播整体具有沿着河谷往层结不稳定区的正向和往低层入流风的反向传播的特征。河谷地形是影响对流移动和传播路径的关键;强对流风暴单体生命史均较长,强降雹单体为类超级单体和普通多单体,强降水回波属于多单体线状对流。降雹单体整体比降水单体发展得更强,变化幅度更大,尤其是垂直累积液态水含量的变化更剧烈。强对流开始前单体垂直累积液态水含量均是先增后降;几处局地雷暴大风是由雷暴云团内弱降水在较厚的环境干层蒸发而显著降温所产生的较大负浮力或由线状对流中强降水拖曳导致的强下沉辐散气流造成,雷达回波具有质心急剧下降或中层径向速度辐合特征。 展开更多
关键词 青藏高原 强对流 中小尺度系统 传播 地形
Uncertainty propagation analysis by an extended sparse grid technique
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作者 X.Y.JIA C.JIANG +3 位作者 C.M.FU B.Y.NI C.S.WANG M.H.PING 《机械工程前沿:英文版》 CSCD 2019年第1期33-46,共14页
In this paper,an uncertainty propagation analysis method is developed based on an extended sparse grid technique and maximum entropy principle,aiming at improving the solving accuracy of the high-order moments and hen... In this paper,an uncertainty propagation analysis method is developed based on an extended sparse grid technique and maximum entropy principle,aiming at improving the solving accuracy of the high-order moments and hence the fitting accuracy of the probability density function(PDF)of the system response.The proposed method incorporates the extended Gauss integration into the uncertainty propagation analysis.Moreover,assisted by the Rosenblatt transformation,the various types of extended integration points are transformed into the extended Gauss-Hermite integration points,which makes the method suitable for any type of continuous distribution.Subsequently,within the sparse grid numerical integration framework,the statistical moments of the system response are obtained based on the transformed points.Furthermore,based on the maximum entropy principle,the obtained first four-order statistical moments are used to fit the PDF of the system response.Finally,three numerical examples are investigated to demonstrate the effectiveness of the proposed method,which includes two mathematical problems with explicit expressions and an engineering application with a black-box model. 展开更多
关键词 uncertainty propagation ANALYSIS EXTENDED SPARSE grid maximum entropy principle EXTENDED GAUSS integration Rosenblatt transformation HIGH-ORDER MOMENTS ANALYSIS
On the Study of Wave Propagation and Distributionin the Global Ocean 预览
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作者 LIU Min ZHAO Dongliang 《中国海洋大学学报:英文版》 SCIE CAS CSCD 2019年第4期803-811,共9页
Based on the simulation with SWAN wave model and data of ERA-Interim from 1979 to 2016, how the waves propagate globally and why swell pools distribute in the eastern ocean were investigated in this study. The simulat... Based on the simulation with SWAN wave model and data of ERA-Interim from 1979 to 2016, how the waves propagate globally and why swell pools distribute in the eastern ocean were investigated in this study. The simulation results show that waves from North Pacific and North Atlantic mainly propagate southeastward or southward and swells generated in Southern Ocean spread northeastward. The waves from high latitude regions spread along the east coast and encounter in the tropical Pacific and Atlantic to form swell fronts around equator and then turn eastward. As the weak wind field with numerous swell inflows, swell pools are gener- ally located on the eastern side of the ocean basin, where the swell index S are greater than 0.9 calculated using ERA-20C data for the period of 1981 2010. Another remarkable feature is that swell pools move southward and split into two parts in winter, while they move northward and merge together in summer. 展开更多
关键词 WAVE propagation SWAN SWELL FRONT SWELL POOL WAVE energy density
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A FEniCS implementation of the phase field method for quasi-static brittle fracture
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作者 HIRSHIKESH Sundararajan NATARAJAN Ratna Kumar ANNABATTULA 《结构与土木工程前沿:英文版》 EI CSCD 2019年第2期380-396,共17页
In the recent years, the phase field method for simulating fracture problems has received considerable attention. This is due to the salient features of the method: 1) it can be incorporated into any conventional fini... In the recent years, the phase field method for simulating fracture problems has received considerable attention. This is due to the salient features of the method: 1) it can be incorporated into any conventional finite element software;2) has a scalar damage variable is used to represent the discontinuous surface implicitly and 3) the crack initiation and subsequent propagation and branching are treated with less complexity. Within this framework, the linear momentum equations are coupled with the diffusion type equation, which describes the evolution of the damage variable. The coupled nonlinear system of partial differential equations are solved in a 'staggered? approach. The present work discusses the implementation of the phase field method for brittle fracture within the open-source finite element software, FEniCS. The FEniCS provides a framework for the automated solutions of the partial differential equations. The details of the implementation which forms the core of the analysis are presented. The implementation is validated by solving a few benchmark problems and comparing the results with the open literature. 展开更多
关键词 phase field method FEniCS BRITTLE FRACTURE CRACK PROPAGATION VARIATIONAL theory of FRACTURE
Attenuation of rock blasting induced ground vibration in rock-soil interface 预览
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作者 Bhagya Jayasinghe Zhiye Zhao +2 位作者 Anthony Goh Teck Chee Hongyuan Zhou Yilin Gui 《岩石力学与岩土工程学报:英文版》 CSCD 2019年第4期770-778,共9页
Blasting has been widely used in mining and construction industries for rock breaking.This paper presents the results of a series of field tests conducted to investigate the ground wave propagation through mixed geolo... Blasting has been widely used in mining and construction industries for rock breaking.This paper presents the results of a series of field tests conducted to investigate the ground wave propagation through mixed geological media.The tests were conducted at a site in the northwestern part of Singapore composed of residual soil and granitic rock.The field test aims to provide measurement data to better understand the stress wave propagation in soil/rock and along their interface.Triaxial accelerometers were used for the free field vibration monitoring.The measured results are presented and discussed,and empirical formulae for predicting peak particle velocity (PPV) attenuation along the ground surface and in soil/rock were derived from the measured data.Also,the ground vibration attenuation across the soil-rock interface was carefully examined,and it was found that the PPV of ground vibration was decreased by 37.2% when it travels from rock to soil in the vertical direction. 展开更多
关键词 Rock BLASTING Field tests BLAST wave propagation PEAK particle velocity (PPV) Rock-soil INTERFACE
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海上丝绸之路视域下中国南路棉花传播研究 预览
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作者 赵红艳 胡荒静琳 +2 位作者 郭可潍 叶洪光 刘安定 《丝绸》 CAS CSCD 北大核心 2019年第8期99-105,共7页
针对海上丝绸之路与中国南路棉花传播之间的关系问题,运用文献研究与田野调察的研究方法,认为中国南路棉花传播之路是由复杂的陆路和海路网络组成,其中海上丝绸之路起到关键性的作用。研究表明:1)中国南路棉花在先秦时期已由印度经缅甸... 针对海上丝绸之路与中国南路棉花传播之间的关系问题,运用文献研究与田野调察的研究方法,认为中国南路棉花传播之路是由复杂的陆路和海路网络组成,其中海上丝绸之路起到关键性的作用。研究表明:1)中国南路棉花在先秦时期已由印度经缅甸进入滇西,到了南北朝时期扩散至广西与越南沿海地区,从而为开启海上棉花之路奠定了必要的条件;2)南宋时期中国培育出的草本亚洲棉,适应了江南地区的气候,从而为南路棉向江南地区推进提供了最佳棉种;3)元代黄道婆沿着海上丝绸之路抵达上海,在黎族棉纺织技术的基础上融合汉族先进的织造技术创造出棉花“衣被天下”的局面。 展开更多
关键词 海上丝绸之路 棉花 传播 黄道婆 纺织技术
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Influences of bubble size distribution on propagation of acoustic waves in dilute polydisperse bubbly liquids 预览
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作者 Yu-ning Zhang Zi-biao Jiang +4 位作者 Jin Yuan Ting Chen Yu-ning Zhang1 Ning-ning Tang Xiao-ze Du 《水动力学研究与进展:英文版》 SCIE EI CSCD 2019年第1期50-57,共8页
The present paper studies the influences of the bubble size distribution on the propagation of acoustic waves in dilute polydisperse bubbly liquids theoretically.The proposed approach is validated by using available e... The present paper studies the influences of the bubble size distribution on the propagation of acoustic waves in dilute polydisperse bubbly liquids theoretically.The proposed approach is validated by using available experimental data in the literature.It is revealed that the bubble size distribution has impacts on both the wave speed and the wave attenuation.Specifically,the minimum wave speed together with the corresponding frequency could be both significantly affected by the bubble size distribution (e.g.,the standard deviation).Furthermore,the maximum wave attenuation in the frequency response curve is also sensitive to the variations of the bubble size distribution. 展开更多
关键词 Cavitation gas BUBBLES WAVE PROPAGATION WAVE speed WAVE attenuation
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Monte Carlo sampling for error propagation in linear regression and applications in isochron geochronology
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作者 Yang Li Shuang Zhang +4 位作者 Richard Hobbs Camila Caiado Adam D.Sproson David Selby Alan D.Rooney 《科学通报:英文版》 SCIE EI CSCD 2019年第3期189-197,共9页
Geochronology is essential for understanding Earth’s history. The availability of precise and accurate isotopic data is increasing;hence it is crucial to develop transparent and accessible data reduction techniques a... Geochronology is essential for understanding Earth’s history. The availability of precise and accurate isotopic data is increasing;hence it is crucial to develop transparent and accessible data reduction techniques and tools to transform raw mass spectrometry data into robust chronological data. Here we present a Monte Carlo sampling approach to fully propagate uncertainties from linear regressions for isochron dating. Our new approach makes no prior assumption about the causes of variability in the derived chronological results and propagates uncertainties from both experimental measurements(analytical uncertainties) and underlying assumptions(model uncertainties) into the final age determination.Using synthetic examples, we find that although the estimates of the slope and y-intercept(hence age and initial isotopic ratios) are comparable between the Monte Carlo method and the benchmark‘‘Isoplot' algorithm, uncertainties from the later could be underestimated by up to 60%, which are likely due to an incomplete propagation of model uncertainties. An additional advantage of the new method is its ability to integrate with geological information to yield refined chronological constraints. The new method presented here is specifically designed to fully propagate errors in geochronological applications involves linear regressions such as Rb-Sr, Sm-Nd, Re-Os, Pt-Os, Lu-Hf, U-Pb(with discordant points),Pb-Pb and Ar-Ar. 展开更多
关键词 LINEAR regression ISOCHRON GEOCHRONOLOGY UNCERTAINTY PROPAGATION MONTE Carlo Isoplot
湖南地区野生千斤拔属资源调查及大叶千斤拔野生变家种技术探索
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作者 龚力民 林丽美 +7 位作者 刘浩 王智 曾晓艳 刘塔斯 李伏君 龚云 张鹏 廖端芳 《中医药导报》 2019年第10期50-52,共3页
目的:了解湖南地区野生千斤拔属资源分布概况,开展湖南地区大叶千斤拔野生变家种种植技术研究,为实现规模化生产奠定基础。方法:通过踏查法对湖南地区的千斤拔属野生资源进行调查;走访法了解大叶千斤拔种植技术,采用种子育苗繁殖和野生... 目的:了解湖南地区野生千斤拔属资源分布概况,开展湖南地区大叶千斤拔野生变家种种植技术研究,为实现规模化生产奠定基础。方法:通过踏查法对湖南地区的千斤拔属野生资源进行调查;走访法了解大叶千斤拔种植技术,采用种子育苗繁殖和野生移栽进行大叶千斤拔人工种植试验研究。结果:湖南地区的野生千斤拔属资源仅零星分布;人工种植的大叶千斤拔病虫害较少,种植1年后的亩产(干品根)平均为372kg,种植后2年半平均亩产为464kg,在湖南地区适合人工种植。结论:湖南地区野生的千斤拔资源近濒危,非常有必要进行大叶千斤拔野生变家种种植技术推广。 展开更多
关键词 千斤拔属 大叶千斤拔 繁殖 栽培
山茱萸良种繁育栽植技术 预览
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作者 王剑辉 王浩 李雪 《陕西林业科技》 2019年第2期111-113,共3页
经多次实地踏查和走访调研总结,山茱萸在陕西省境内的秦巴山区15县生长具有得天独厚的优势,主要分布在陕西的汉中、商洛地区。尤其在周至、眉县、太白、佛坪、洋县、丹凤等地发现有成片的自然分布,到目前已成为药材山茱萸的主产区,2014... 经多次实地踏查和走访调研总结,山茱萸在陕西省境内的秦巴山区15县生长具有得天独厚的优势,主要分布在陕西的汉中、商洛地区。尤其在周至、眉县、太白、佛坪、洋县、丹凤等地发现有成片的自然分布,到目前已成为药材山茱萸的主产区,2014年2月国家质检总局正式批准"周至县山茱萸"为国家地理标志的保护产品。结合各地域立地条件,特将选育的良种进行科学栽培,实现优产丰产。 展开更多
关键词 山茱萸 良种 繁育 栽植技术
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Understanding hydraulic fracture propagation behavior in tight sandstone-coal interbedded formations: an experimental investigation
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作者 Peng Tan Yan Jin +4 位作者 Liang Yuan Zhen-Yu Xiong Bing Hou Mian Chen Li-Ming Wan 《石油科学:英文版》 SCIE CAS CSCD 2019年第1期148-160,共13页
Whether hydraulic fractures could connect multiple gas zones in the vertical plane is the key to fracturing treatment to jointly exploit coalbed methane and tight sandstone gas through integrative hydraulic fracturing... Whether hydraulic fractures could connect multiple gas zones in the vertical plane is the key to fracturing treatment to jointly exploit coalbed methane and tight sandstone gas through integrative hydraulic fracturing in tight sandstone-coal interbedded formations. Laboratory true triaxial hydraulic fracturing experiments were conducted on layered specimens with different combination types of natural sandstone and coal to simulate the propagation behavior of hydraulic fractures. The effects of the fracture initiation position, fracturing fluid viscosity and injection rate were discussed. The results showed that different fracture morphologies could be found. When initiating from coal seams, three patterns of fracture initiation and propagation were obtained:(1) The main hydraulic fracture initiated and propagated along the natural fractures and then diverged due to the effects of in situ stress and formed secondary fractures.(2) The hydraulic fracture initiated and propagated in the direction of the maximum horizontal stress.(3) Multiple fractures initiated and propagated at the same time. With the same fracturing fluid viscosity and injection rate, the hydraulic fractures initiating in sandstones had greater chances than those in coal seams to penetrate interfaces and enter neighboring layers. Excessively small or large fracturing fluid viscosity and injection rate would do harm to the vertical extension height of the induced fracture and improvement of the stimulated reservoir volume. Compared with operation parameters (fracturing fluid viscosity and injection rate), the natural weak planes in coals were considered to be the key factor that affected the fracture propagation path. The experimental results would make some contributions to the development of tight sandstone-coal interbedded reservoirs. 展开更多
关键词 Hydraulic FRACTURING Fracture PROPAGATION Sandstone-coal interbed LAYERED formation
衡阳地区怀化秤锤树苗木繁殖技术 预览
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作者 梁称福 付美云 《湖南农业科学》 2019年第2期73-75,共3页
为加快怀化秤锤树在衡阳的栽培与利用,引种怀化秤锤树进行了种子繁殖、扦插繁殖、组培繁殖等技术研究,并总结了3种繁殖技术。怀化秤锤树种子具有深休眠特性,须经沙藏越冬后,翌年春季3—4月播种。树枝条扦插的最佳时段为5月中下旬至6月下... 为加快怀化秤锤树在衡阳的栽培与利用,引种怀化秤锤树进行了种子繁殖、扦插繁殖、组培繁殖等技术研究,并总结了3种繁殖技术。怀化秤锤树种子具有深休眠特性,须经沙藏越冬后,翌年春季3—4月播种。树枝条扦插的最佳时段为5月中下旬至6月下旬,选择3~5a树龄的当年生半木质化健壮枝条作为插穗,采用黄泥、河沙、泥炭(体积比为2∶1∶1)配制混合基质,扦插后2周覆膜保温保湿,成活率85%以上。组培繁殖时采集当年生未木质化嫩枝的单芽茎段接种在培养基MS+BA1.0mg/L+NAA0.1mg/L+蔗糖30.0g/L+琼脂6.0g/L上,培养25~30d后,可长出3~5个芽,接着转移到培养基MS+BA2.0mg/L+NAA0.2mg/L+蔗糖30.0g/L+琼脂6.0g/L上进行继代增殖培养,30d后增殖倍数可达3~4倍,将继代增殖芽苗转接到培养基1/2MS+IBA0.5mg/L+NAA0.2mg/L+蔗糖30.0g/L+琼脂6.0g/L上进行生根培养,20d后产生不定根,生根率达95%以上。 展开更多
关键词 怀化秤锤树 引种 繁殖 衡阳
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Tissue Culture and Rapid Propagation of Spathiphyllum kochii Engl. et Krause 预览
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作者 Shufang FAN Furong MAO +3 位作者 Bin LIU Dawei JIAN Xiaoqin LI Xuezhi ZUO 《农业生物技术:英文版》 CAS 2019年第2期86-89,共4页
[Objectives] This study was conducted on tissue-culture rapid propagation techniques of Spathiphyllum kochii Engl. et Krause.[Methods] With lateral buds of S. kochii as explants, the effects of such four basic media a... [Objectives] This study was conducted on tissue-culture rapid propagation techniques of Spathiphyllum kochii Engl. et Krause.[Methods] With lateral buds of S. kochii as explants, the effects of such four basic media as MS, B5, Nitsch and Wpm and the ratio of two hormones (1, 2, 3 mg/L 6-BA and 0.1, 0.3, 0.5 mg/L NAA) on bud proliferation of S. kochii were studied by the complete test method, and the effect of the ratio of the two hormones (0.25, 0.50, 1.00 mg/L NAA and 1.0, 1.5 mg/L IBA ) on rooting of S. kochii as well as the effect of substrate ratio (perlite and peat soil at 1∶ 9, 2∶ 8, 3∶ 7, 4∶ 6 and 5∶ 5) on its transplanting survival rate were also studied.[Results] The best basic medium for the rapid propagation of S. kochii was MS. The best hormone ratio suitable for bud proliferation was 2 mg/L6-BA+0.1 mg/L NAA, and the average number of buds proliferated at 45 d was 3.04. The average bud height was 2.05 cm;the most suitable medium for rooting was1/2MS+1mg/L IBA+0.25 mg/L NAA, and its rooting rate was 100%;and the best transplanting substrate was 5∶5 perlite and peat. The soil ratio had a survival rate of 94%.[Conclusions] This study provides a theoretical basis for the improvement of the transplanting survival rate of test-tube S. kochii plantlets. 展开更多
关键词 Spathiphyllum kochii Engl. ET Krause TISSUE CULTURE RAPID PROPAGATION
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Movie Score Prediction Model Based on Movie Plots 预览
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作者 Hui Xie Haomeng Wang +1 位作者 Chen Zhao Zhe Wang 《国际计算机前沿大会会议论文集》 2019年第2期633-634,共2页
With the rapid development of the movie industry, it is vital to evaluate and predict a movie’s quality. In this paper, a movie score prediction model is proposed based on the movie plots. Movie data was processed wi... With the rapid development of the movie industry, it is vital to evaluate and predict a movie’s quality. In this paper, a movie score prediction model is proposed based on the movie plots. Movie data was processed with the word2vec method, and the linear regression model and back propagation neural network algorithm were employed to establish the movie score prediction model. The high-quality classic movie plots of high-scoring movies summed up by big data contributed to a high synthesis of the wonderful content of the film. Experimental results show that it is effective in terms of movie evaluation and prediction, and helpful in understanding people’s preferences for movie plots. 展开更多
关键词 MOVIE bridge PLOT MOVIE SCORE prediction Linear Regression Model BACK PROPAGATION neural network
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多肉植物‘樱水晶’不同繁殖方法比较试验 预览
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作者 陈汉鑫 甘亚海 万学锋 《南方园艺》 2019年第4期8-10,共3页
樱水晶为百合科十二卷属多年生肉质草本植物,通过试验研究了不同繁殖方法对樱水晶繁殖效率的影响,结果表明,使用组培苗于春季用自配基质泥炭土:蛭石:赤玉土=6:2:1成活率最高,30d时95.9%,45d时94.7%,60d时达94.2%,苗生长快、健壮,种植60... 樱水晶为百合科十二卷属多年生肉质草本植物,通过试验研究了不同繁殖方法对樱水晶繁殖效率的影响,结果表明,使用组培苗于春季用自配基质泥炭土:蛭石:赤玉土=6:2:1成活率最高,30d时95.9%,45d时94.7%,60d时达94.2%,苗生长快、健壮,种植60d苗直径达3.4cm。因此,在生产上使用组培苗可明显提高樱水晶成活率和商品率。 展开更多
关键词 多肉植物 樱水晶 繁殖
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超声波在粘弹性混凝土介质中传播机理研究 预览
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作者 鲁光银 张志勇 +1 位作者 朱自强 付渝渝 《物探化探计算技术》 CAS 2019年第3期299-307,共9页
混凝土是一种含有骨料、水泥浆、钢筋、波纹管包裹的预应力孔道及空洞、孔隙的多相非均匀复合材料,作为一种粘弹性介质,超声在混凝土中传播机理比较复杂,常规的弹性声波方程不能确切地模拟超声传播方式。这里从粘弹性介质材料性质出发,... 混凝土是一种含有骨料、水泥浆、钢筋、波纹管包裹的预应力孔道及空洞、孔隙的多相非均匀复合材料,作为一种粘弹性介质,超声在混凝土中传播机理比较复杂,常规的弹性声波方程不能确切地模拟超声传播方式。这里从粘弹性介质材料性质出发,推导了基于Kelvin粘弹性介质模型的高阶有限差分方程,通过建立几种粘弹性混凝土介质数值模型,模拟了超声波在混凝土中的传播过程,分析了含空洞、裂隙等不同缺陷的混凝土介质中超声波的波形特性,讨论了缺陷部位波形的变化规律,探讨了空洞、裂隙等不同缺陷对超声传播机理的影响以及能量分布的差异,为准确判断识别混凝土内部不同结构的缺陷提供科学借鉴。 展开更多
关键词 混凝土 超声 传播 模拟 缺陷 开尔文粘弹性介质
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混合血小板裂解液对人骨髓间充质干细胞原代培养、增殖和成骨分化的影响 预览
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作者 徐杨 林飞跃 尹晓明 《中国当代医药》 2019年第18期13-18,共6页
目的研究混合血小板裂解液(pHPL)对体外培养的人骨髓间充质干细胞(hBMMSCs)原代培养、增殖和成骨分化的影响。方法使用临床过期的多份浓缩血小板混合,多次冻融激活后制备pHPL,分别使用胎牛血清(FBS)和pHPL加基础培养液原代培养hBMMSCs,... 目的研究混合血小板裂解液(pHPL)对体外培养的人骨髓间充质干细胞(hBMMSCs)原代培养、增殖和成骨分化的影响。方法使用临床过期的多份浓缩血小板混合,多次冻融激活后制备pHPL,分别使用胎牛血清(FBS)和pHPL加基础培养液原代培养hBMMSCs,比较两组中的细胞形态、表面标志物、细胞骨架、细胞周期和增殖率,并在加入经典成骨诱导液后检测两组中碱性磷酸酶含量、成骨相关基因含量和矿化结节形成,比较其成骨分化能力。结果FBS和pHPL培养组均能较好地支持hBMMSCs的原代培养,两组中细胞形态、表面标志物、细胞骨架、细胞周期均无明显差异,但pHPL组在5、7d时的细胞增殖率明显高于FBS组(P<0.05);在成骨诱导后,pHPL组中碱性磷酸酶含量、成骨相关基因含量也明显高于FBS组(P<0.05),两组中细胞均可以形成成熟的矿化结节。结论pHPL能够很好支持hBMMSCs的原代培养、增殖和成骨分化,且较FBS能更好地促进其增殖和成骨分化。 展开更多
关键词 人血小板裂解液 骨髓间充质干细胞 原代培养 增殖 成骨分化
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