ENUMERATION OF ORIENTED TREES AND FREE TREES WITH A GIVEN NUMBER OF LEAVES

D. E. Knuth has widely discussed some combinatorial properties and the application in computer science on binary trees, ordered trees, oriented trees and free trees, and given some formulas for the number of all the above structurally different trees with n nodes. Recently Wang Zhenyu gave formulas of the total leaf number for the preceding trees. Classifying these results carefully, Wang

Phosphine-free synthesis of FeTe2 nanoparticles and self-assembly into tree-like nanoarchitectures

Manipulating the self-assembly of transition metal telluride nanocrystals(NCs) creates opportunities for exploring new properties and device applications. Iron ditelluride(FeTe2) has recently emerged as a new class of magnetic semiconductor with three-dimensional(3D) magnetic ordering and narrow band gap structure, yet the self-assembly of FeTe2 NCs has not been achieved. Herein, the tree-like FeTe2 nanoarchitectures with orthorhombic crystal structure have been successfully synthesized by hot-injection solvent thermal approach using phosphine-free Te precursor. The morphology, size, and crystal structure have been investigated using transmission electron microscopy(TEM), high-resolution TEM(HRTEM),and powder x-ray diffraction(XRD). We study the formation process of tree-like FeTe2 NCs according to trace the change of the sample morphology with the reaction time. It was found that the FeTe2 nanoparticles show oriented aggregation and self-assembly behavior with the increase of reaction time, which is attributed to size-dependent magnetism properties of the samples. The magnetic interaction is thought to be the driving force of nanoparticle self-organization.

无爪图的支撑k-端点树的存在性

树T中度为1的点称为叶子,叶子数目不超过k的树称为k-端点树.图中存在一个哈密尔顿路,说明图中存在恰好含有两个叶子的支撑树.自然就有了关于哈密尔顿路问题的一个推广:考虑图中至多有k个叶子的支撑树即支撑k-端点树的存在性问题.通过控制集参数,确定了连通无爪图中存在支撑k-端点树条件.

日本落叶松无性系种子园和优树半同胞家系苗期比较

为缩短育种周期,降低田间试验规模,构建高阶遗传改良和繁育群体的应用材料。在沙坝国家落叶松(Larix gmelinii)、云杉(Larix asperata)良种基地,采用随机完全区组试验设计,对25个日本落叶松(Larix kaempferi(Lamb.)car.)无性系种子园和30个人工林优树自由授粉家系苗期的生长性状及遗传变异进行比较。同时以2年生苗高作为选择指标,对家系选择和家系内单株选择进行对比。结果表明:日本落叶松种子园自由授粉家系和人工林优树自由授粉家系的1年生及2年生苗的地径、苗高差异不显著,两者间2年生苗新梢生长量差异达显著水平(P<0.05)。人工林优树自由授粉家系比种子园自由授粉家系新梢生长量高3.27%。种子园自由授粉家系及人工林优树自由授粉家系1年生及2年生苗的生长性状均具有丰富的遗传变异,两者生长性状的表型变异系数均大于遗传变异系数。家系遗传力大于单株遗传力,家系选择潜力大。人工林优树自由授粉家系相比种子园自由授粉家系,其具有更加丰富的遗传变异。人工林优树自由授粉家系苗高的家系遗传力及单株遗传力分别为0.920及0.434,是种子园自由授粉家系的1.16及27.13倍。以2年生苗高为选择指标,苗高大于群体均值为家系入选标准,种子园及人工林优树自由授粉家系的入选率分别是52.00%及46.67%。家系选择时,种子园和人工林优树自由授粉家系苗高的遗传增益分别为6.46%及9.98%。在家系选择的基础上进行优良单株选择,单株入选率为8.00%及7.80%。单株选择时,苗高的遗传增益分别是1.42%及32.15%。在人工林优树自由授粉家系及家系内单株进行选择,其遗传增益分别是种子园自由授粉的1.54及22.64倍。日本落叶松种子园自由授粉家系和人工林优树自由授粉家系均具有丰富的遗传变异,人工林优树自由授粉家系生长性状的遗传变异比种子园自由授粉家系更为丰富,选择潜力更大。

基于苹果叶片与药液界面特性的果园农药精准喷雾量计算模型的建立

为保证果树精准施药,减少药剂流失,本研究结合果树叶片冠层参数、界面性质和果园农药去向,建立了苹果园农药精准喷雾量的计算模型,以指导不同植保机械在不同果园栽种模式下的农药喷施方式。选取不同发育期‘富士’苹果叶片为研究对象,通过测定叶片表观表面自由能与冠层参数(叶面积指数、平均叶倾角),建立药液表面张力与苹果叶片最大持液量之间的关系,基于叶片最大持液量与果树冠层参数计算全树最大持液量,结合苹果园农药去向,建立了苹果园农药精准喷雾量计算模型。以担架柱塞泵式机动喷雾机在乔化稀植苹果园和风送式自走履带喷雾机在矮砧密植苹果园的施药行为为例,验证所建模型的实用性。结果表明:乔化稀植苹果园于苹果生长前期,使用担架柱塞泵式机动喷雾机,按计算用药液量施药,较常规用药液量节省药液量37.40%,生长后期则节省药液量18.75%。矮砧密植苹果园于苹果生长后期,使用风送式自走履带喷雾机,按计算用药液量施药,较常规用药液量节省药液量28%。且防效与常规药液用量无显著性差异。此模型将苹果叶片界面性质与施药器械相结合,不仅可根据果园实际情况对果园施药量进行精准计算,还可对果园某一时期农药药液的适用性进行评价,并基于实际情况调控药液量、喷雾机械参数,从而达到精准施药的目的。

Motzkin树叶点的计数

本文主要研究了n条边的Motzkin树的叶点总数.分别利用符号化方法和双射证明了n条边的Motzkin树的叶点总数与长度为n的自由的Motzkin路的个数相等.利用这个双射也可以得到n个内点的完全二元树的叶点总数,并且给出了半长为n的且有k个峰的Dyck路的个数是Narayana数这一结论一个新的证明.

K_（1，r）－Free图的生成树及其算法

证明了任一连通的Ｋ（１，ｒ）－Ｆｒｅｅ图都有最大度小于等于ｒ的生成树，并建立了算法。

一种未添加防腐剂芦荟凝胶的配方设计

文章以化妆品常见菌种为指示菌,采用T/SHRH 017-2019《团体标准化妆品防腐挑战试验》中的方法评估添加复合精油对芦荟凝胶产品的防腐效果。结果显示,茶树精油、薰衣草精油、欧薄荷精油混合物在产品中的添加量为0.75%、1.00%时,通过了防腐效能评估,其中复配精油添加量为0.75%的芦荟凝胶通过了安全性测试,而复配精油添加量为1.00%的芦荟凝胶未通过安全性测试,说明该添加量对皮肤具有轻微刺激性。

K_4-minor-free图的线性2-荫度

图G的线性2-荫度la_2(G)是将G分解为k个边不交的森林的最小整数k,其中每个森林的分支树是长度至多为2的路.本文证明了若G是最大度为Δ(G)的K_4-minor-free图,则la_2(G)≤(Δ(G)+5)/2.

K_（1，r）－free图的次限制树多项式算法

设Ｇ＝（Ｖ，Ｅ）为一连通图，ｄ＞０整数．Ｇ中存在生成树Ｔ，使得Δ（Ｔ）小于ｄ吗？这一问题已被证明是ＮＰ－完全的，故不太可能有多项式解法．本文证明了当Ｇ是Ｋ１，ｒ－ｆｒｅ时，则有Ｏ（ｎ２）的算法求出Ｇ的生成树Ｔ，使Δ（Ｔ）≤ｒ。

Analysis on Free Spindle Pruning Mode and Related Factors in Fuji Apple

In order to clarify the correlations between the free spindle pruning mode and various factors in Fuji apple,the growth data of the free spindle-shaped short branch Fuji apple Tianhong No. 2 and the free spindle-shaped long branch Fuji apple Changfu No. 2 in the Apple Demonstration Park of Xingtang County,Hebei Province were investigated. Using SPSS statistical software,the correlations between the stem tapering grade and various growth traits were analyzed. The results showed that in Tianhong No. 2,the stem tapering grade was negatively correlated with various growth traits of the central shaft,and the correlation coefficients between the stem tapering grade and the central shaft total thickness,the central shaft average thickness,the central shaft total length and the central shaft average length were-0. 228,-0. 033,-0. 411 and-0. 430,respectively; and in Changfu No. 2,the stem tapering grade was positively correlated with various growth traits of the central shaft,and the correlation coefficients between the stem tapering grade and the central shaft total thickness,the central shaft average thickness,the central shaft total length and the central shaft average length were 0. 475,0. 181,0. 120 and 0. 258,respectively. This paper can provide a scientific basis for guiding the construction of free spindle pruning mode in densely planted dwarf apple trees.

Resizable, Rescalable and Free-Style Visualization of Hierarchical Clustering and Bioinformatics Analysis

Graphical representation of hierarchical clustering results is of final importance in hierarchical cluster analysis of data. Unfortunately, almost all mathematical or statistical software may have a weak capability of showcasing such clustering results. Particularly, most of clustering results or trees drawn cannot be represented in a dendrogram with a resizable, rescalable and free-style fashion. With the “dynamic” drawing instead of “static” one, this research works around these weak functionalities that restrict visualization of clustering results in an arbitrary manner. It introduces an algorithmic solution to these functionalities, which adopts seamless pixel rearrangements to be able to resize and rescale dendrograms or tree diagrams. The results showed that the algorithm developed makes clustering outcome representation a really free visualization of hierarchical clustering and bioinformatics analysis. Especially, it possesses features of selectively visualizing and/or saving results in a specific size, scale and style (different views).

关于K_（1，r）－free图的连通因子

本文证明了每个连通的Ｋ１，ｒ－ｆｒｅｅ图Ｇ，如果有［ｆ，ｇ］－因子Ｆ，则它就有包含Ｆ的［ｆ，ｇ＋ｒ－１］连通因子．

Vangenes Cell-Free DNA采血管与 Streck Cell-Free DNA采血管在无创产前检测应用中的效果比较

目的:比较Vangenes■Cell-Free DNA采血管和Streck■Cell-Free DNA 采血管对血液样品的运输保存效果.方法:通过静脉抽血, 18名志愿者分别使用Vangenes■Cell-Free DNA 采血管与Streck■Cell-Free DNA采血管各采集一管10mL血液.经过约50h运输样本回到实验室,进行血浆分离、游离DNA提取、构建文库、上机测序并进行建库浓度、测序数据的unique read counts、 GC%以及duplication值等分析.结果:经比较, Vangenes ?Cell-Free DNA采血管保存样品在血浆颜色、建库浓度以及测序数据的unique read counts、 GC%以及duplication值等达到了Streck■Cell-Free DNA 采血管保存样品相似的结果,二者不存在显著性差异.结论:在血液样品运输保存过程中, Vangenes■Cell-Free DNA采血管可有效阻止有核细胞破裂导致的基因组DNA对于游离DNA的污染,对于利用胎儿游离DNA进行的无创产前检测技术具有重要意义.

Stability of weighted spectral distribution in a pseudo tree-like network model

The comparison of networks with different orders strongly depends on the stability analysis of graph features in evolving systems. In this paper, we rigorously investigate the stability of the weighted spectral distribution（i.e., a spectral graph feature） as the network order increases. First, we use deterministic scale-free networks generated by a pseudo treelike model to derive the precise formula of the spectral feature, and then analyze the stability of the spectral feature based on the precise formula. Except for the scale-free feature, the pseudo tree-like model exhibits the hierarchical and small-world structures of complex networks. The stability analysis is useful for the classification of networks with different orders and the similarity analysis of networks that may belong to the same evolving system.

不同经营模式对蒙古栎林土壤有机碳组分的长效性影响

准确把握长期不同经营措施下蒙古栎林(Quercus mongolica)土壤有机碳及其组分碳含量的变化,对于深入理解森林经营管理对土壤碳库的长效影响作用及其固碳机制具有重要意义。以黑龙江省哈尔滨市丹清河实验林场蒙古栎天然次生林为研究对象,采用物理分组方法,研究目标树经营(经营强度45%、40%、70%,折灌除草)、综合抚育经营(经营强度45%、40%,不清理灌草)、无干扰经营对土壤有机碳及其组分碳含量的长效影响。结果表明,在23 a的经营实践后,与无干扰经营相比,目标树经营和综合抚育经营对土壤总有机碳含量的影响不显著,综合抚育经营显著降低了19.94%的粗自由颗粒有机碳(cfPOC)含量(P<0.05),而目标树经营显著提高了矿物结合态有机碳(MOC)含量97.92%(P<0.05),细自由颗粒有机碳(ffPOC)和物理保护颗粒有机碳(i POC)含量在3种经营模式间无显著差异。粗自由颗粒有机碳占土壤总有机碳含量的70.63%—76.53%,是土壤固存有机碳的主要形式。土壤C/N依次按颗粒有机碳、物理保护有机碳和矿物结合态有机碳逐渐降低,反映了有机碳在土壤中转化和固定的过程。从提升土壤质量及固碳能力方面考虑,目标树经营是蒙古栎次生林最优经营模式,无干扰模式次之,综合抚育经营对土壤质量和固碳增汇的影响较小。

椰树精神融入海南自贸港建设的时代内涵、价值意蕴与实践路径

椰树精神是海南人民精神文化的浓缩,是琼崖革命精神的赓续,更是中华民族精神文化谱系的重要组成部分。首先,笔者通过深入研究、充分论证,梳理出椰树精神融入海南自由贸易港建设的时代内涵。其次,凝练出其价值意蕴,即椰树精神不仅是实现中国式现代化海南样板的时代要求,还是培育和践行社会主义核心价值观的重要途径,更是贯彻新发展理念、全力推进海南自贸港的现实需要。最后,从传承椰树精神、弘扬椰树精神和创新椰树精神3方面设计出优化路径,以期为海南自贸港产业发展添砖加瓦,以椰树精神统领海南干事创业之精气神,这不仅是建设自由贸易港的现实需要,也是推进文化自信自强、铸就社会主义文化新辉煌的应有之义。

茶树无糖组织培养生根技术研究

本文以平阳特早茶树为试验材料,在无糖组织培养条件下,使用IBA对茶树组培苗进行诱导生根试验。结果表明,与1/2MS培养基(不添加植物生长调节剂对照)相比,1/2MS+0.5 mg/L IBA培养基(添加植物生长调节剂)对平阳特早茶树组培苗不定根的发生有显著促进作用,生根率达到68%。本研究建立了适合于平阳特早茶树无糖组培生根的技术方案,可为茶树组培苗木繁育提供新的方法。

深水气田井口抬升影响因素分析及应对措施

随着某深水气田的开发,各口生产气井井口都出现了不同程度的抬升现象,井控风险较大,破坏了气井井筒完整性,影响气井正常生产寿命,严重时还可能会造成生产管线断裂,直接影响气田安全生产。因此,通过对气井井口抬升影响因素进行分析,建立气井井口装置抬升的多管柱耦合系统井口抬升计算模型,对井口抬升高度进行计算,并与现场实测值进行对比分析。结果表明未固井段管柱温度变化是引起采油树抬升的主要原因,并给出了针对性的应对措施及建议,为改善或解决气田井口抬升问题提供了借鉴。

苹果无病毒树的生长和结果表现

连续 8年调查了富士、金矮生、甜黄魁及国光无病毒树的树高、冠径、干径、每株树的新枝总数、新枝总长等生长指标和进入初结果期的结果株率 ,均表明明显高于同品种、同树龄有病毒对照树。无病毒金矮生、富士和甜黄魁品种每株树的累积结果量分别比有病毒对照树高 54 .7%、45 .0 %和 41 .6 %。无病毒富士、金矮生及国光果实硬度明显大于相应品种的对照果 ;维生素C、总糖、总酸及果皮中花青苷含量均高于相应品种的对照。