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天女木兰的组织培养 被引量:27
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作者 杜凤国 刁绍起 +4 位作者 王欢 杨德冒 孙曙光 王子明 刘春强 《东北林业大学学报》 CAS CSCD 北大核心 2006年第2期42-43,共2页
以天女木兰幼树和一年生的实生苗的幼嫩茎段为外植体,采用不同激素配比的培养基对天女木兰的组培技术进行了研究,培育出了天女木兰的组培苗。适宜天女木兰侧芽分化的培养基为:B5+0.5mg·L-16-BA+0.3mg·L-1IBA;适宜生根的培养基... 以天女木兰幼树和一年生的实生苗的幼嫩茎段为外植体,采用不同激素配比的培养基对天女木兰的组培技术进行了研究,培育出了天女木兰的组培苗。适宜天女木兰侧芽分化的培养基为:B5+0.5mg·L-16-BA+0.3mg·L-1IBA;适宜生根的培养基为:1/4MS+1.0mg·L-1IBA+0.5mg·L-1NAA。 展开更多
关键词 天女木兰 组织培养 培养基
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The Hausdorff measure of the self-similar sets——The Koch curve 被引量:14
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作者 周作领 《Science China Mathematics》 SCIE 1998年第7期723-728,共6页
The self similar sets satisfying the open condition have been studied. An estimation of fractal, by the definition can only give the upper limit of its Hausdorff measure. So to judge if such an upper limit is its exac... The self similar sets satisfying the open condition have been studied. An estimation of fractal, by the definition can only give the upper limit of its Hausdorff measure. So to judge if such an upper limit is its exact value or not is important. A negative criterion has been given. As a consequence, the Marion’s conjecture on the Hausdorff meas\| ure of the Koch curve has been proved invalid. 展开更多
关键词 self similar SETS HAUSDORFF MEASURE and DIMENSION koch curve.
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On the Lower Bound of the Hausdorff Measure of the Koch Curve 被引量:8
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作者 ZhiWeiZHU ZuoLingZHOU BaoGuoJIA 《Acta Mathematica Sinica,English Series》 SCIE CSCD 2003年第4期715-728,共14页
This paper gives a lower bound of the Hausdorff measure of the Koch curve bymeans of the mass distribution principle.
关键词 koch curve Hausdorff dimension Hausdorff measure
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吡虫啉亚致死剂量对豆蚜生长发育和种群参数的影响 被引量:6
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作者 刘昌燕 万正煌 +3 位作者 焦春海 李莉 刘良军 陈宏伟 《湖北农业科学》 2018年第23期89-91,共3页
为了解吡虫啉不同亚致死剂量对豆蚜(Aphis craccivora Koch)试验种群参数的影响,阐明豆蚜发育及繁殖与亚致死剂量的关系。在(25±1)℃,光周期L∶D=16 h∶8 h,相对湿度(RH)70%~80%条件下,采用带叶浸虫法确定吡虫啉的亚致死剂量,通... 为了解吡虫啉不同亚致死剂量对豆蚜(Aphis craccivora Koch)试验种群参数的影响,阐明豆蚜发育及繁殖与亚致死剂量的关系。在(25±1)℃,光周期L∶D=16 h∶8 h,相对湿度(RH)70%~80%条件下,采用带叶浸虫法确定吡虫啉的亚致死剂量,通过叶碟饲养,记录其发育历期、产蚜量和寿命。结果表明,豆蚜经处理后,平均寿命表现为LC_(30)处理后显著短于对照,而LC_(20)和LC_(10)处理与对照无显著差异;平均产蚜量表现为LC_(30)处理后显著低于对照组。LC_(10)、LC_(20)、LC_(30)处理豆蚜后,F_1代若虫和成虫期与对照差异不显著,但若蚜存活率均显著低于对照。表明吡虫啉不同亚致死剂量处理豆蚜后,对其寿命和繁殖力均起抑制作用。 展开更多
关键词 豆蚜(Aphis craccivora koch) 吡虫啉 亚致死效应 生长发育
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Elastic Wave Propagation in Lattice Metamaterials with Koch Fractal 被引量:8
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作者 Pengcheng Zhao Kai Zhang Zichen Deng 《Acta Mechanica Solida Sinica》 SCIE EI CSCD 2020年第5期600-611,共12页
In this study,the wave propagation properties of lattice metamaterials with Koch fractal structures are investigated in terms of band structures and directional wave propagation.The analytical models of lattice metama... In this study,the wave propagation properties of lattice metamaterials with Koch fractal structures are investigated in terms of band structures and directional wave propagation.The analytical models of lattice metamaterials are established using the finite element method,and the dispersion relation is solved using the Bloch’s theorem.The band structures of the lattice metamaterials with different numbers of iterations are studied,and the group velocities at a selected frequency are calculated to analyze the directional wave propagation characteristics.Furthermore,dynamic responses of the finite structures are calculated using commercial finite element software to verify the band gaps and directional wave propagation behaviors in the lattice metamaterials.The results show that multiple and low band gaps are present in the lattice materials with various geometric parameters of the Koch fractal,and the position of the lowest band gap decreases as the number of iterations increases.The results indicate the potential applications of lattice metamaterials with Koch fractals for vibration isolation and multi-functional design. 展开更多
关键词 Elastic wave propagation Lattice metamaterial koch fractal Band gap Group velocity
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Neofusicoccum parvum causing canker of seedlings of Juglans regia in China 被引量:5
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作者 Zhongdong Yu Guanghui Tang +2 位作者 Shaobin Peng Hui Chen Meizhi Zhai 《Journal of Forestry Research》 SCIE CAS CSCD 2015年第4期1019-1024,共6页
Cankered, dying seedlings of Juglans regia were observed in Shaanxi province in the northwest region of China. Neofusicoccum parvum was isolated from these cankered tissues, with the identification based on mor- pholo... Cankered, dying seedlings of Juglans regia were observed in Shaanxi province in the northwest region of China. Neofusicoccum parvum was isolated from these cankered tissues, with the identification based on mor- phology and an ITS-nrDNA sequence. In order to demonstrate how cultures of N. parvum could cause the expected symptoms, artificial infection, using these isolates and re-isolation of the pathogen, was used. This is the first report on this taxon as a walnut canker pathogen in China. 展开更多
关键词 Forest tree disease ITS-nr-DNA koch's postulates Neofusicoccum parvum WALNUT
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东北岩高兰醋酸乙酯部位化学成分及其对大鼠酒精性脂肪肝作用研究 被引量:7
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作者 王谦博 郑成琳 +2 位作者 金司阳 郭慧 王振月 《中草药》 CAS CSCD 北大核心 2016年第18期3164-3168,共5页
目的对东北岩高兰Empetrum nigrum var.japonicum地上部分70%乙醇提取物的醋酸乙酯萃取部位进行化学成分和对大鼠酒精性脂肪肝(AFL)作用的研究,为东北岩高兰的开发和利用提供科学依据。方法利用色谱分离技术和波谱解析技术进行分离纯... 目的对东北岩高兰Empetrum nigrum var.japonicum地上部分70%乙醇提取物的醋酸乙酯萃取部位进行化学成分和对大鼠酒精性脂肪肝(AFL)作用的研究,为东北岩高兰的开发和利用提供科学依据。方法利用色谱分离技术和波谱解析技术进行分离纯化、结构分析及鉴定。采用45%的酒精ig方法对SD大鼠进行AFL造模。观察东北岩高兰醋酸乙酯部位对AFL大鼠肝指数、血清学、肝组织匀浆等指标的影响。结果从东北岩高兰地上部分70%乙醇提取物的醋酸乙酯萃取部位分离得到8个化合物,分别鉴定为β-谷甾醇(1)、熊果酸(2)、乌苏醇(3)、2′,4′-二羟基二氢查耳酮(4)、2′,4′-二羟基查耳酮(5)、7-羟基二氢黄酮(6)、4′-甲氧基-2′-羟基二氢查耳酮(7)、4,2′,4′-三羟基查耳酮(8)。与模型组比较,给予东北岩高兰醋酸乙酯部位提取物后,大鼠肝指数降低明显,血清中三酰甘油(TG)、总胆固醇(TC)降低,血清酶学丙氨酸转氨酶(ALT)、天冬氨酸转氨酶(AST)降低,肝组织匀浆中超氧化物歧化酶(SOD)、谷胱甘肽(GSH)升高。结论化合物1~4、6~8为首次从东北岩高兰中分离得到。东北岩高兰的醋酸乙酯部位对大鼠AFL具有治疗效果。 展开更多
关键词 东北岩高兰 Β-谷甾醇 熊果酸 乌苏醇 2′ 4′-二羟基二氢查耳酮 酒精性脂肪肝
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海南豇豆蚜对敌敌畏、三氟氯氰菊酯、辛硫磷和氰戊菊酯的敏感性测定 被引量:4
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作者 陈青 卢芙萍 《中国农学通报》 CSCD 北大核心 2009年第13期179-181,共3页
为了解海南豇豆蚜对敌敌畏、三氟氯氰菊酯、辛硫磷和氰戊菊酯的抗药性状况,就海南省崖城、金江、通什和两院地区豇豆上的豇豆蚜对敌敌畏、三氟氯氰菊酯、辛硫磷和氰戊菊酯的敏感性进行了初步调查与研究。试验结果表明,不同地区豇豆蚜对... 为了解海南豇豆蚜对敌敌畏、三氟氯氰菊酯、辛硫磷和氰戊菊酯的抗药性状况,就海南省崖城、金江、通什和两院地区豇豆上的豇豆蚜对敌敌畏、三氟氯氰菊酯、辛硫磷和氰戊菊酯的敏感性进行了初步调查与研究。试验结果表明,不同地区豇豆蚜对敌敌畏、三氟氯氰菊酯、辛硫磷和氰戊菊酯的敏感性存在明显差异。崖城和金江两地区豇豆蚜种群对三氟氯氰菊酯、辛硫磷、氰戊菊酯和敌敌畏均表现出较强的抗药性。以两院地区豇豆蚜作为敏感品系,崖城和金江两地区豇豆蚜种群对三氟氯氰菊酯、辛硫磷、氰戊菊酯、DDV的LC50抗性比值分别为21.86倍、22.78倍、17.88倍、13.49倍和10.91倍、12.59倍、11.47倍和13.49倍。通什地区的豇豆蚜对三氟氯氰菊酯、辛硫磷、氰戊菊酯和DDV的抗性也有一定的提高,与两院种群LC50抗性比值分别为1.58倍、12.27倍、4.45倍和2.28倍。而且崖城、金江和通什地区豇豆蚜种群对三氟氯氰菊酯、辛硫磷、氰戊菊酯和DDV抗性种群的异质性很强。 展开更多
关键词 海南豇豆蚜(Aphis craccivora koch) 三氟氯氰菊酯 敌敌畏 辛硫磷 氰戊菊酯 敏感性
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三个英文音乐术语的辨义、溯源与应用--勋伯格调性音乐理念对西方音乐分析学科和曲式教学的影响 被引量:6
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作者 郭新 《中央音乐学院学报》 CSSCI 北大核心 2016年第1期3-26,共24页
西方音乐理论中,术语的形成与含义都有其历史发展变化的根源和使用范围的限定,不是固定而一成不变的。本文首先借助勋伯格对sentence,phrase和period的定义及相应的实际谱例,澄清在译文上出现的混淆状态,并追溯这些词义的来源和运用范围... 西方音乐理论中,术语的形成与含义都有其历史发展变化的根源和使用范围的限定,不是固定而一成不变的。本文首先借助勋伯格对sentence,phrase和period的定义及相应的实际谱例,澄清在译文上出现的混淆状态,并追溯这些词义的来源和运用范围;然后,通过对西方1980年以来在理论观念和术语系统化发展与完善方面重要文献的综述,梳理出20世纪后半叶,勋伯格传统调性音乐教学理论对西方音乐分析学科和北美地区曲式教学影响的脉络。 展开更多
关键词 术语 主题写作类型 音乐分析学科 曲式教学 勋伯格 科赫 拉茨
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Morphological and electrophysiological properties of single myocardial cells from Koch triangle of rabbit heart 被引量:3
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作者 REN Fu-xian NIU Xiao-lin +4 位作者 OU Yan HAN Zhen-hua LING Feng-dong ZHOU Shi-sheng LI Ya-jie 《Chinese Medical Journal》 SCIE CAS CSCD 2006年第24期2075-2084,共10页
Background The morphological and electrophysiological characteristics of cardiac cells in Koch triangle are still disputed. We studied the appearance and electrical properties of these diverse myocytes to elucidate th... Background The morphological and electrophysiological characteristics of cardiac cells in Koch triangle are still disputed. We studied the appearance and electrical properties of these diverse myocytes to elucidate their complex electrophysiological phenomena. Methods Experiments were conducted using cooled charge coupling device (CCD) system and whole cell, patch clamp technique to determine the morphology, action potential and sodium current density of single viable myocytes enzymatically isolated from the Koch triangle of rabbit hearts. Results Morphologically, cardiac cells in shape of spider, tiny spindle, slender spindle, rod and strip were observed in percentage of 3.0±0.3, 35.0±5.0, 15.0±2.0, 40.0±5.0 and 6.0±0.7 respectively. The cellular dimensions and capacitance gradually increased in the above order (all P〈0.05). Electrophysiologically, action potential configurations recorded from them were similar respectively to nodal (N), atrial nodal (AN), nodal Hisian (NH), atrial (A) and Hisian like potentials obtained from the intact atrioventricular nodal preparations. Diastolic depolarization appeared in all myocytes except for rod cells. Sodium current density increased in the order of tiny spindle, strip, rod, slender spindle cell (all P〈0.05), but could not be detected in spider-shaped cells. Linear regression analysis revealed that membrane capacitance was correlated negatively to the rate of diastolic depolarization r=-0.70, P〈0.001, but positively to maximum depolarization potential, amplitude of action potential, upstroke velocity and maximum peak value of sodium current density r=0.84, 0.80, 0.87 and 0.75, respectively; all P〈0.001. Conclusions The results demonstrated that spider-shaped, spindle, rod and strip cells in Koch triangle might correspond to pacemaking, transitional, atrial and Purkinje like cells, respectively. Furthermore, tiny spindle and slender spindle cells were referred to transitional cell α (TCα) and β (TCβ) accordingly consid 展开更多
关键词 triangle of koch transitional cell action potential sodium current patch clamp
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Morphological and ISSR molecular markers reveal genetic diversity of wild hawthorns (Crataegus songorica K. Koch.) in Xinjiang, China 被引量:3
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作者 SHENG Fang CHEN Shu-ying +5 位作者 TIAN Jia LI Peng QIN Xue WANG Lei LUO Shu-ping LI Jiang 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2017年第11期2482-2495,共14页
The wild hawthorn species, Crataegus songorica K. Koch., is an important wild germplasm resource in Xinjiang, China that has been endangered in recent years. The genetic diversity of C. songorica K. Koch. germplasm in... The wild hawthorn species, Crataegus songorica K. Koch., is an important wild germplasm resource in Xinjiang, China that has been endangered in recent years. The genetic diversity of C. songorica K. Koch. germplasm in five populations from Daxigou, Xinjiang, China were evaluated based on phenotypic traits and ISSR molecular markers to provide basic infor- mation on resource protection, rational utilization and genetic improvement. The F-value for the phenotypic differentiation coefficient of the 33 traits measured ranged from 0.266 to 15.128, and mean value was 13.85%. The variation among populations was found to be lower than that within population. A total of 303 loci were detected within the five populations by 12 primers. Within 298,polymorphic loci, the polymorphism was 98.35%, showing a high genetic diversity in C. songorica K. Koch. The gene diversity within population, total population genetic diversity, genetic differentiation coefficient and gene flow were 0.2779, 0.3235, 0.1408, and 3.0511, respectively. Our results showed that C. songorica K. Koch. from Xinjiang has a high level of genetic diversity at both the phenotypic and molecular levels. Significant genetic differentiation existed within population and the differentiation trend showed a regional association. And in this study, in situ and ex situ conser- vation approaches were raised for wild hawthorn protection utilization. 展开更多
关键词 phenotypic traits ISSR marker genetic diversity Crataegus songorica K. koch. germplasm resources molecular marker
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A new isoquinoline derivative from the leaves of Magnolia sieboldii K.Koch 被引量:3
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作者 Di Wu Ru Ping Wang +2 位作者 Shao Jiang Song Li Jun Wu Hui Yuan Gao 《Chinese Chemical Letters》 SCIE CAS CSCD 2010年第12期1446-1448,共3页
Magnoline(1),a new isoquinoline derivative,was isolated from the leaves of Magnolia sieboldii K.Koch(Magnoliaceae).Its structure was elucidated on the basis of spectral analysis including 1D,2D NMR and HR-TOF-MS.
关键词 Magnolia sieboldii K. koch ISOQUINOLINE Structural identification
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墨江蜈蚣与少棘蜈蚣对致病真菌和细菌体外生长的影响 被引量:5
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作者 吴刚 王金焕 +3 位作者 冉永禄 迟程 叶文娟 唐向辉 《皮肤病与性病》 北大核心 1992年第2期12-14,共3页
本文分析了少棘和墨江蜈蚣对8种致病真菌和7种细菌体外生长的影响。两种蜈蚣的2%NaHCO_3和蒸馏水提取液以及油脂对真菌影响极小;3%CH_3COOH 提取液强烈抑制真菌生长,但无杀菌作用,测定了相应的最小抑菌浓度(MIC)。各提取物对细菌均无... 本文分析了少棘和墨江蜈蚣对8种致病真菌和7种细菌体外生长的影响。两种蜈蚣的2%NaHCO_3和蒸馏水提取液以及油脂对真菌影响极小;3%CH_3COOH 提取液强烈抑制真菌生长,但无杀菌作用,测定了相应的最小抑菌浓度(MIC)。各提取物对细菌均无抑制作用。 展开更多
关键词 少棘蜈蚣 墨江蜈蚣 真菌 细菌
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Exact scaling for the mean first-passage time of random walks on a generalized Koch network with a trap 被引量:2
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作者 张静远 孙伟刚 陈关荣 《Chinese Physics B》 SCIE EI CAS CSCD 2012年第3期525-529,共5页
In this paper, we study the scaling for the mean first-passage time (MFPT) of the random walks on a generalized Koch network with a trap. Through the network construction, where the initial state is transformed from... In this paper, we study the scaling for the mean first-passage time (MFPT) of the random walks on a generalized Koch network with a trap. Through the network construction, where the initial state is transformed from a triangle to a polygon, we obtain the exact scaling for the MFPT. We show that the MFPT grows linearly with the number of nodes and the dimensions of the polygon in the large limit of the network order. In addition, we determine the exponents of scaling efficiency characterizing the random walks. Our results are the generalizations of those derived for the Koch network, which shed light on the analysis of random walks over various fractal networks. 展开更多
关键词 mean first-passage time random walks koch networks
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Sodium current kinetics of transitional myocytes in Koch triangle of rabbit hearts 被引量:2
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作者 REN Fu-xian NIU Xiao-lin +4 位作者 OU Yan XIE Song-mei LING Feng-dong ZHOU Shi-sheng LI Ya-jie 《Chinese Medical Journal》 SCIE CAS CSCD 2008年第21期2185-2191,共7页
Background Few studies have explored the inward sodium current (INa) kinetics of transitional cardiomyocytes. This study aimed to explore the kinetics of transitional cardiomyocytes types α and β. Methods The whol... Background Few studies have explored the inward sodium current (INa) kinetics of transitional cardiomyocytes. This study aimed to explore the kinetics of transitional cardiomyocytes types α and β. Methods The whole-cell patch clamp technique was used to study the rapid INa of isolated transitional cardiomyocytes in the Koch triangle of rabbit hearts. Results Maximal amplitude and density of INa in type a and type β was (-1627±288) pA (α), (-35.17±6.56) pA/pF (β) and (-3845±467) pA (α), (-65.64±10.23) pA/pF (β) (P 〈0.05). Steady state activation curves of INa, fitted to a Boltzmann distribution for both types, were sigmoid in shape. Half activation voltage and slope factors did not significantly differ between types at (-43.46±0.85) mV (α), (-41.39±0.47) mV (β) or (9.04±0.66) mV (α), (11.08±0.89) mV (β). Steady state inactivation curves of INa, fitted to a Boltzmann distribution in both types were inverse "S" shape. Half inactivation voltage and slope factors were (-109.9±0.62) mV (α), (-107.5±0.49) mV (β) and (11.78±0.36) mV (α), (11.57±0.27) mV (β), (P〉0.05), but time constants of inactivation were significantly different at (1.10±0.19) mV (α) and (2.37±0.33) ms (β), (P 〈0.05). Time constants of recovery from inactivation of INa for both types were (122.16±27.43) mV (α) and (103.84±2.8.97) ms (β) (P 〈0.05). Conclusions Transitional cardiomyocytes in rabbit hearts show a heterogeneous, voltage gated and time dependent fast inward sodium current. Types α and β show the features of INa similar to those in slow- and fast-response myocytes, with probably better automaticity and conductivity, respectively. 展开更多
关键词 sodium current transitional myocyte koch triangle TACHYCARDIA
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Quinoline alkaloids isolated from Scolopendra subspinipes mutilans 被引量:2
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作者 Yan-fang Li Wu-zhan Liu +4 位作者 Jian-wei Fan Chuan-liang Huang Li-hua Deng Hui-fang Zhuang Yong-xia Guan 《Chinese Herbal Medicines》 CAS 2019年第3期344-346,共3页
Objective: To study the quinoline alkaloids from the ethanol extract of Scolopendra subspinipes mutilans(SSM).Methods: The chemical constituents were isolated and purified by macroporous resin column, medium pressure ... Objective: To study the quinoline alkaloids from the ethanol extract of Scolopendra subspinipes mutilans(SSM).Methods: The chemical constituents were isolated and purified by macroporous resin column, medium pressure preparation chromatography, and semi-preparative HPLC. Their structures were elucidated by IR,MS, and NMR experiments.Results: Three quinolone alkaloids were obtained and identified as 3-hydroxy-4-methoxyquinolin-8-yl hydrogen sulfate(1), jineol-8-sulfate(2), and jineol(3), respectively.Conclusion: Compound 1 is a new compound from SSM. 展开更多
关键词 3–hydroxy-4-methoxyquinolin-8-yl hydrogen SULFATE jineol jineol-8-sulfate QUINOLINE ALKALOIDS SCOLOPENDRA subspinipes mutilans L. koch
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Lift-Off Effect of Koch and Circular Differential Pickup Eddy Current Probes
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作者 Guolong Chen Zheng Cao +3 位作者 Shuaishuai Zhang Ji Wei Wei Gao Wuyin Jin 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2024年第2期283-293,共11页
A flexible or planar eddy current probe with a differential structure can suppress the lift-off noise during the inspection of defects.However,the extent of the lift-off effect on differential probes,including differe... A flexible or planar eddy current probe with a differential structure can suppress the lift-off noise during the inspection of defects.However,the extent of the lift-off effect on differential probes,including different coil structures,varies.In this study,two planar eddy current probes with differential pickup structures and the same size,Koch and circular probes,were used to compare lift-off effects.The eddy current distributions of the probes perturbed by 0°and 90°cracks were obtained by finite element analysis.The analysis results show that the 90°crack can impede the eddy current induced by the Koch probe even further at relatively low lift-off distance.The peak-to-peak values of the signal output from the two probes were compared at different lift-off distances using finite element analysis and experimental methods.In addition,the effects of different frequencies on the lift-off were studied experimentally.The results show that the signal peak-to-peak value of the Koch probe for the inspection of cracks in 90°orientation is larger than that of the circular probe when the lift-off distance is smaller than 1.2 mm.In addition,the influence of the lift-off distance on the peak-to-peak signal value of the two probes was studied via normalization.This indicates that the influence becomes more evident with an increase in excitation frequency.This research discloses the lift-off effect of differential planar eddy current probes with different coil shapes and proves the detection merit of the Koch probe for 90°cracks at low lift-off distances. 展开更多
关键词 Eddy current testing Differential pickup probe Fractal koch curve Flexible eddy current probe
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山东省苍山大蒜(Allium sativum)贮藏期新病原菌的分离与鉴定 被引量:4
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作者 钟文文 刘婷婷 +4 位作者 赵志龙 高翠娟 安冬玉 王一宇 许俊杰 《安徽农业科学》 CAS 2018年第21期140-144,151,共6页
对临沂市兰陵县苍山大蒜贮藏期病害情况进行了调查,采用柯赫氏法则和病斑显微观察法对病原菌株lyu20170012进行了验证,并通过形态学特征和r DNA ITS序列分析对其进行了鉴定。结果表明,从病斑上分离得到4种真菌和1种细菌,经致病性检测发... 对临沂市兰陵县苍山大蒜贮藏期病害情况进行了调查,采用柯赫氏法则和病斑显微观察法对病原菌株lyu20170012进行了验证,并通过形态学特征和r DNA ITS序列分析对其进行了鉴定。结果表明,从病斑上分离得到4种真菌和1种细菌,经致病性检测发现菌株lyu20170012具有致病性,将lyu20170012菌株鉴定为尖孢镰刀菌(Fusarium oxysporum)。 展开更多
关键词 尖孢镰刀菌 大蒜鳞茎病害 柯赫氏法则 病原菌
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Two-dimensional Wave Equations with Fractal Boundaries 被引量:1
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作者 Lin Tao MA Wei Yi SU 《Acta Mathematica Sinica,English Series》 SCIE CSCD 2013年第12期2321-2342,共22页
This paper focuses on two cases of two-dimensional wave equations with fractal boundaries. The first case is the equation with classical derivative. The formal solution is obtained. And a definition of the solution is... This paper focuses on two cases of two-dimensional wave equations with fractal boundaries. The first case is the equation with classical derivative. The formal solution is obtained. And a definition of the solution is given. Then we prove that under certain conditions, the solution is a kind of fractal function, which is continuous, differentiable nowhere in its domain. Next, for specific given initial position and 3 different initial velocities, the graphs of solutions are sketched. By computing the box dimensions of boundaries of cross-sections for solution surfaces, we evaluate the range of box dimension of the vibrating membrane. The second case is the equation with p-type derivative. The corresponding solution is shown and numerical example is given. 展开更多
关键词 Von koch type curve p-type derivative two-dimensional wave equation fractal boundary fractal dimension
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Helicobacter is preserved in yeast vacuoles! Does Koch's postulates confirm it? 被引量:1
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作者 Nader Alipour Nasrin Gaeini 《World Journal of Gastroenterology》 SCIE CAS 2017年第12期2266-2268,共3页
The manuscript titled "Vacuoles of Candida yeast behave as a specialized niche for Helicobacter pylori(H.pylori)" not only has not been prepared in a scientific manner but the methodology used was not adequa... The manuscript titled "Vacuoles of Candida yeast behave as a specialized niche for Helicobacter pylori(H.pylori)" not only has not been prepared in a scientific manner but the methodology used was not adequate, and therefore the conclusion reached was not correct. First of all, "yeast" is a broad terminology covering a great number of genera and species of unicellular micro-organisms. The authors should have defined the organism with its binary scientific name. This measure would allow experiment reproduction by the scientific community. Moreover, the criteria established by Robert Koch to identify a specific microorganism or pathogen was not adopted in the methodology used. Regarding the methodology applied, use of the chicken eggyolk(Ig Y) antibody and PCR of the apparently tainted yeast population to prove H. pylori existence in the yeast vacuoles might be main factors for their wrong conclusions. Bacterial tropism toward yeast extract is a known phenomenon, and yeast extract is one of the main ingredients in culture media. Their internalization through phagocytosis or similar pathways does not seem possible or practical because of the thick and cellulosic yeast wall. While the small size of yeast cells does not support their ability in harboring several H. pylori, other observations such as inefficiency of antifungal therapy as anti-Helicobacter therapy strongly reject the conclusion reached by the above-mentioned article. 展开更多
关键词 Helicobacter pylori YEAST Acanthamoeba castellanii koch’s postulates
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