Subjects: Biology >> Botany >> Applied botany submitted time 2024-05-15 Cooperative journals: 《广西植物》
Abstract： Bsang is a folk activity with unique ethnic cultural characteristics on the Qinghai-Tibet Plateau (QTP), and it plays an important role in the daily life of Zang people. There are abundant bsang plant resources and related bsang cultural knowledge on the QTP, to investigate, document, and research Xizang bsang plants and related traditional knowledge, the research team conducted four ethnobotanical surveys on bsang plants in Xizang. Interviews were conducted with 459 informants from 22 townships, documenting 83 species of bsang plants belonging to 36 genera across 19 families. The results were as follows: (1) People of different regions, ages, and genders possess extensive knowledge of bsang plants; (2) Hordeum vulgare var. coeleste, Juniperus indica, Rhododendron anthopogon and have high cultural value (CV) indices, making them crucial in bsang activities; (3) The utilization of bsang plants demonstrates regional and substitutive characteristics, reflecting the local practices of scientifically managing and sustainably collecting of bsang plant resources. This study contributes to the inheritance of bsang activities and the biodiversity conservation and sustainable utilization of bsang plant resources.
Subjects: Biology >> Botany >> Applied botany submitted time 2022-07-05 Cooperative journals: 《广西植物》
Abstract： To study the chemical constituents from the branches and leaves of Trichilia connaroides, silica gel, MCI, C18, Sephadex LH-20 and HPLC were applied for the isolation and purification of the constituents. The structures were identified by physicochemical property and spectrum analysis. The results were as follow: (1) Six compounds were obtained from methanol extract of T. connaroides, their structures were identified as Trichiconnarone A (1), 3β, 21-dihydroxy-24-methylenecycloartane (2), 3-Oxo-threo-23, 24, 25-trihydroxytirucall-7-ene (3), 16-dehydeoxy-23β-hydroxyliasenin F (4), ergost-5, 24(28)-diene-3β, 23S-diol (5), 7α-hydrositosteol (6). (2) Compounds 1 is new lignans, 2-4 are triterpenoids, 5 and 6 steroids, and 2-5 were isolated from this plant for the first time. This study provided scientific basis for therational development and utilization of T. connaroides.
Subjects: Astronomy >> Astrophysical processes submitted time 2020-05-06 Cooperative journals: 《天文研究与技术》
Abstract： 本文利用调整流量基准面的方法修正19个费米Blazars的光学波段流量与色指数，通过对比修正前后色指数与星等相关关系，研究多普勒因子对于色指数变化机制的影响。研究表明：（1）修正前，只有5个源呈现明显的BWB趋势，2个源呈现明显的RWB趋势；（2）经过修正后，有9个源呈现明显的BWB趋势，6个源呈现弱的BWB趋势，只有4个源的色指数与星等不存在相关关系；（3）大约有一半的源的色变机制受到多普勒聚束效应的影响，在修正后，这些源的色指数与星等的相关性增强；（4）多普勒因子的变化可能是造成BWB趋势变弱的原因。通过研究色指数和星等的相关关系，能进一步解释Blazars的辐射机制。
Subjects: Astronomy >> Astrophysical processes submitted time 2019-04-26 Cooperative journals: 《天文研究与技术》
Abstract： 通过收集数据，用标准吸积盘方法，短时标光变法，连续波混响滞后法，微引力透镜法分析了活动星系核吸积盘辐射区半径，并对四种方法进行分析讨论。结果表明:（1）将耀变体和类星体参数比较，发现两子类的中心黑洞质量、光度和吸积盘辐射区半径都没有明显差别。本文选择了高光度源进行研究，因此出现了两子类以上参数无明显区别的情况；（2）短时标光变法得到的吸积盘辐射区半径比和黑洞质量没有明显的相关性；（3）连续波混响滞后法得到的吸积盘辐射区半径比对黑洞质量的依赖性高于标准α盘模型法，对于无法确定中心黑洞质量的源，可以利用连续波混响滞后法得到吸积盘辐射区半径；（4）微引力透镜法得到的吸积盘辐射区半径比和黑洞质量没有明显的相关性，且该方法只适用于存在微引力透镜效应的类星体，（5）这些方法从观测上证明了吸积盘辐射区半径与黑洞质量存在相关性，验证了标准模型成立。为进一步在观测上寻找这四种方法所需要的源提供了理论上的指导。对活动星系核的吸积盘辐射区半径研究有重要意义。
Subjects: Astronomy >> Astrophysical processes submitted time 2018-11-21 Cooperative journals: 《天文研究与技术》
Abstract： 本文搜集和计算了 734 个 Fermi 耀变体样本，其中包括 322 个蝎虎天体（BL Lacs） （其中 148 个 HBLs、73 个 IBLs 以及 101 个 LBLs）和 412 个平谱射电类星体（FSRQs）（其中 18 个 HFSRQs，45 个 IFSRQs，349 个 LFSRQs）。我们研究了每个子类的红移分布，黑洞质量分布以及γ 射线光度的分布，并对其红移、黑洞质量、γ 射线光度以及同步峰值频率的相关性进行了分析，结果表明：（1）根据红移与γ 射线光度分别从高到低的排序，Fermi耀变体的演化序列遵循：FSRQs→BL Lacs，且 HSPs→ISPs→LSPs，但根据黑洞质量从高到低所得到的演化序列不同，这可能是黑洞质量的估计误差以及黑洞质量样本数量较少造成的；（2）Fermi 耀变体每个子类的红移与黑洞质量、黑洞质量与γ 射线光度之间存在正相关； （3）Fermi 耀变体每个子类的红移、γ 射线光度分别与同步峰频之间存在反相关，黑洞质量与同步峰频之间不存在相关性。
Subjects: Astronomy submitted time 2018-09-13 Cooperative journals: 《天文研究与技术》
Abstract：本文给出了四种分析类星体长周期光变的方法，用一个模拟的周期信号y=sinθ 检验这四种分析方法，结果表明：①、天体光变采样的数据点个数相对少到一定值时，Jurkevich方法，时间补偿离散傅里叶变换分析方法（DCDFT），离散相关分析方法（DCF）和功率谱密度分析方法（PSD）的分析结果不一样，获取最短的连续数据点后，Jurkevich方法分析结果在四种方法中可能最为精确可靠，且计算方法简捷实用。②、获得了Jurkevich分析方法的最佳参数，当m=9时分析结果最佳。③、用m=9时的Jurkevich方法分析了类星体3C 279天体及3C 454.3天体的光变周期，得出3C 279天体的可能光变周期为，3C 454.3天体的可能光变周期为457d。
Subjects: Astronomy submitted time 2018-09-13 Cooperative journals: 《天文研究与技术》
Abstract： 本文利用UMRAO数据库的22个耀变体源的偏振数据，根据Lazarian ＆ Pogosyan的理论模型进行分析研究了耀变体射电波段的偏振随波长的变化，得出不同类的耀变体偏振随波长的变化的原因。其结果表明，与Lazarian ＆ Pogosyan的理论模型吻合较好。由此我们得出如下结论：（1）反常去偏振耀变体源中反常法拉第旋光起主导作用，反常去偏振相对较少；（2）热辐射与同步辐射混合作用，高频波段的偏振度就小于低频波段的偏振度（反常去偏振）；（3）当被观测波段波长小于吸积盘热辐射所对应的维恩波长时，高频波段的偏振度就大于低频波段的偏振度（常规去偏振）。
Subjects: Astronomy >> Astrophysical processes submitted time 2018-05-21 Cooperative journals: 《天文研究与技术》
Abstract： 在收集大量数据的基础上，用时间补偿离散傅里叶变换、Jurkevich方法和离散相关分析法分析了PKS 0735+178的B波段和V波段光变周期，发现该天体具有（4.330.41） 年的光变周期，其中心黑洞质量的下限为0.22106Mʘ。
Subjects: Biology >> Ecology submitted time 2017-11-29 Cooperative journals: 《中国生态农业学报》
Abstract： On the Loess Plateau, maize morphological structure and yield performance were restricted by rainfall capacity and soil nutrient status. Resource competition in intercroped cultivation can provide a postive effect on the individual establishment and biomass allocation of maize cultivars. The research on root morphology and biomass allocation of maize under integrated influence of annual rainfall level, planting densities and intercropped cultivation aimed for clear and definite the necessity and importance of intercropped models on the grain yield and water use efficiency (WUE) increase. Field experiment was conducted at a classic dry farmming region in a semi-arid region of Loess Plateau in Northwest China. Two maize cultivars (Zhengdan 958, Z958 and Shendan 16, S16) with two planting densities as 45000 plants. hm-2 and 75000 plants .hm-2, intercroped planting in two rows interlaced, above- and belowground competitive growth and biomass accumulation were measured and analyzed for assessing the correlation among biomass allocation, root distribution, grain yield and WUE. The results showed as: (1) Soil water deficiency showed an effective force to root surface area (SA) decrease of S16 at flowering stage under low intercroped density, and SA of Z958 decreased by 30.5% under high intercroped density, water competition was intensified with the intercropped density increase. Over two experimental years, Z958 and S16 intercropping increased root length density (RLD) in 0-20 cm soil layer significantly, denstiy increase and rainwater deficiency both stimulated root growing deeper for water uptaking which then enhanced root competition for water, finally, caused the RLD obvious increase in 30-40 cm soil layer and Z958 appeared deeper root distribution capacity than S16 in two planting densities. (2) Biomass accumulated advantage under intercroped planting had a gentype difference, Z958 appeared growing promotion during vegetative period and that of S16 was during reproductive period. Individual biomass of two maize cultivars decreased with the intercroped density increase, and there had a increase in S16 dry weight during during reproductive growing period compared with that of Z958 in 2011under low intercroped planting density; with high density and more drought condition, maize cultivars intercrops decreased individual biomass accumulation after flowering. (3) the high intercroped density system obtained a increase of harvest index (HI) by 6.0% averagely over two different rainfall years, and ample rain promoted the HI of intercroped group. Root and shoot could grow normally due to inefficient light competition under the sufficient precipitation and low planting density; Soil drought and high intercroped density resulted in the significant decrease of root to shoot rate (RSR) in Z958 because the root competition for water was enhanced. (4) In the drought year (2011), competitive advantage was fully appeared in the two intercroped systems, showed as final yield and WUE increased by 10.3 and 21.4% , 28.2 and 42.0% respectively in the two intercroped densities, furthermore, yield and WUE of Z958 under mixed system were 17.6 and 50.0% higher than S16 over two years. Finally, Z958 showed reasonal biomass distribution and response mechnisim to soil drought under intercropping with S16, through decreased root redundant growth and useless resouces consume. Effective root morphological adjustment and biomass distribution of Z958 were responsible for yield and WUE increase.
Subjects: Astronomy >> Astrophysical processes submitted time 2017-10-20 Cooperative journals: 《天文研究与技术》
Abstract：喷流的形成与黑洞吸积向来密不可分。分析黑洞吸积率与其喷流能量的相关性对研究黑洞内部结构以及喷流形成的具体原因具有重要的意义。从文献资料中收集了24个数据源，这些源包含了13个射电选B LLac天体(RBL)和11个平谱射电类星体(FSRQs )。通过样本数据研究黑洞吸积率与喷流能量以及丫射线流量密度的相关性。研究结果表明:(1)24个活动类星体的吸积率与喷流能量存在明显的相关性，这与Allen等得出的结论相同;(2)射电选B LLac天体与平谱射电类星体的喷流能量分布存在一定差异;(3)射电选BLLac天体的吸积率与丫射线流量密度相关性并不明显，但平谱射电类星体的吸积率与丫射线流量密度之间具有一定的相关性;(4)研究结果进一步证明了喷流能量不仅与黑洞质量有关，同时也很可能与黑洞的吸积存在关系。黑洞喷流的形成很可能是黑洞质量与吸积共同作用的结果。这些研究结果与其他方法获得的结果是一致的。
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