共查询到20条相似文献，搜索用时 234 毫秒
1.
2.
随着数学这门学科的不断发展与细分,在数学分析这个舞台上无穷级数扮演着越来越重要的角色,它的存在使我们对一些复杂的函数处理起来变得简单的多。本文诣在解决一般数项级数sum (f(n)) from n=-∞ to +∞、sum ((-1)~nf(n)) from n=-∞ to +∞的通用求和公式,并例举上述公式在无穷级数求和中的应用。 相似文献
3.
图G有n个顶点,其中λ1,λ2,……λn是它的特征值。图GEstrada指表图G的不变量,它表示为EE(G),值EE(G)=sum from i=1 to n(eλ1)。在本文,证明了EE(G1)相似文献
4.
5.
6.
陈友义 《中国科学院研究生院学报》1985,(1)
设X_1,X_2,X_3…为一串iid一维随机变量,f(x)为其密度函数,本文讨论f(x)的一类核估计 f_n~1(x)=1/nh_#~(1/2) sum from j=1 to n (h_j~(- 1/2)K(x-X_j h_j))的强收敛性,在比较一般的条件下得到较好的收敛速度,并简化了文献中对这类问题复杂的证明方法。 相似文献
7.
《中国科学院研究生院学报》1988,(2)
Vitamin D_2 and vitamin D_3 give a clear polarographic oxidation-wave,respectively,by neopolarography,with a 0.25M solution oflithium perehlorate in ethanol-dimethylformamide(1:1)as the supportingelectrolyte.Peak potentials are both+1.27V(vs.pure Ag plate).Thewave-height is proportional to the concentration in the range from 2.6×10~(-6)M(1μg/ml)to 1.1×10~(-3)M(420μg/ml)for vitamin D_3 and from2.5×10~(-6)M(1μg/ml)to 1.1×10~(-3)M(435μg/ml)for vitamin D_2,respe-ctively.The detection limits are both 1.3×10~(-6)M(0.5μg/ml).Themethod can be satisfactorily applied to the determination of vitamin D_3in injcction.Through various experiments,it is shown that the electrodeprocess of vitamin D at glassy carbon electrode is an irreversible oxida-tion process controlled by diffusion.The value of an is 0.84(α is thetransfer coefficient and n is the number of cleclron in the kineticprocess).n=2.The electrode reaction mechanism has been inferred.Besides,the choices of base solution and of experiment conditions aswell as the stability of vitamin D etc.are also discussed. 相似文献
8.
9.
10.
本文讨论波能传播(沿群速方向)对于波速而言的两个特征方向,它们由波控制方程的具体表达式确定。(1)若波控制方程由表示,式中为某因变量,L为时间导数与空间Laplace算符▽~2(二维或三维)的导数多项式,则群速与波速平行;(2)若波控制方程由表示,式中n、i、j、k取值零或任意正整数,且i+j+k=M=constant(M=1,2,3…N),L为对空间导数而言的M次齐式(L中至少包含有一个时间导数项),则群速与波速垂直;(3)若波控制方程不由上述两式表示,则群速与波速将斜交。 相似文献
11.
Leonurus japonicus Houtt. [L. heterophyllus Sweet, L. artemisia (Lour.) S. Y.
Hu] is one of the most important traditional Chinese medicines used as a remedy for gynaeco-
logical disease since ancient times. A cytological investigation on the species was carried out
and the materials for chromosomal examination were collected from 26 localities in 20 provi-
noes and autonomous regions of this country. The number of chromosomes in root tip cell of
the species was found to be 20 on the whole (Tab. 1:1), agreeing with those reported by Ma and
al.[2] and probably by Chuang and al.[3] as well.
The genus Leonurus L. is variable in its chromosomes with an aneuploidy of x=9, 10 and
12. The present authors would propose that the primitive basic number of chromosome in the
genus is 9, and thus both 10 and 12 are derived, for: (1) among the 9 species (including 1 sub-
species) heretofore cytologically examined, x=9 occurring in 66.7%, x=10 occurring in 22.2%,
while x=12 occurring only in 11.1%; (2) in generaclosely related to the genus under considera-
tion, such as Panzeria, Galeobdolon and Lamium x=9 being the sole basic number.
But L. japonicus exhibits a mixoploidy of 2n=20 (occurring at the rate of 53.30% of the
total amount of cells examined), 2n=18 (30.70%), and 2n=16 (15.99%) in our work. (Table
1). Since the original basic number of chromosome of the genus is 9 as proposed above, 2n=
20 would be considered as a derived one and the occurrence of 2n=18 probably suggests an
early evolutionary trend of 2n=18→20 of the pecies in question. 相似文献
12.
同一个数学题可能有两个或者更多不同的解法、或证法。此方说, 1~2 2~2 3~2 …… n~2=n(n 1)(2n 1)/6这个公式就有好几个证法。若右端的式子已知,可以用数学归纳法证明它。若右端的式子未知,可以用“逐差法”或其他的方法把它导出来。球面三角的余弦定律有两种很不相同的证法。商高定理(直角三角形a~2 b~2=c~2)有一百种以上的证法。积分问题常有不只一种的解法。微分方程式也常有两种或更多种的解法。如果题目的答案不预先知道,多找出一种解法可以查验先得到的答案是否正确。如果用不同的解法得出不同的答案,那么总有一些解法是错误的,或 相似文献
13.
14.
1 引言组合预测的基本含义是把两个或两个以上的预测模型来用加权平均的方式组合为一个模型,而加权系数的确定是最优组合预测模型确定的关键。我国有很多人从事过这方面的研究,得到一些结果(见[1]、[2]).本文根据广义最小二乘法和加权最小一乘法思想,再论最优组合预测模型的确定. 2 根据广义最小二乘法确定最优权系数设对于同一预测问题我们有几种预测方法。 y(?)实际观测值,t=1,2,…,N; y(?)第i种方法的预测值,i=1,2,…,n; (?)=y(?)—y(?)第i种方法的预测误差; W_(?)第i种方法的加权系数,(?)=1; (?)加权组合预测值; e(?)=y(?)—y(?):组合预测误差. 根据广义二乘法的思想,最优组合预测模型,其权系数W=(w_1,…,w_n)~r应使下式中的J达到最小 相似文献
15.
张芝玉 《中国科学院研究生院学报》1982,20(4):402-409
1. The present paper describes the observations of chromosome numbers and
karyomorphology of 2 species of 2 endemic genera and I endemic species of Chinese
Ranunculaceae: Asteropyrum peltatum (Franch.) Drumm et Hutch. 2n=16, x=8;
Kingdonia unifolia Balf. f. et W. W. Sm. 2n=18, x=9 and Calathodes oxycarpa Spra-
gue 2n=16, x=8. The chromosome counts of three ranunculaceous genera are repor-
ted for the first time.
2. The morphylogical, palynological and cytological date in relation to the syste-
matic postition of Asteropyrum, Kingdonia and Calathodes within the family Ranun-
culaceae are diseussed and resulted in following conclusions:
(1). On the basis of the basic number x=8 in Asteropyrum, it is further con-
firmed that this genus is distinct from the r elated genera such as Isopyrum, Dichocarp-
um and other allied taxa.
The comparison of Asteropyrum with Coptis shows that they are identical in short
chromosomes, with magnoflorina and benzylisaquinodine type of alkaloides, but dif-
ferent from coptis in the chromosome numbers (T-type), pantocolpate pollens, united
carpels and the dorsi-ventral type of petioles. In view of these fundamental morpho-
logical and cytological differences, Asterop yrum is better raised to the level of Tribe.
However Asteropyrum and Coptis may represent two divaricate evolutional lines of
Thalictroideae.
(2). The systematic position of the genus Kingdonia has been much disputed in
the past. We support the view of Sinnote (1914), namely, the trilacunar in leaf
traces “the ancient type”, appeared in the angiosperm line very early, while the uni-
lacunar of Kingdonia may be derived from the trilacunar. On the basis of the chromo-
some numbers and morphylogical observation, the present writer accept Tamura’s and
Wang’s treatment by keeping Kingdonia in Ranunculaceae instead of raising it to a
family rank as has been been done by Forster (1961). Kingdonia and Coptis are
similar in having short chromosome with x=9, but with one-seeded fruits; therefore it
is suggested that placed into Thalictroideae as an independent tribe, indicating its close
relationship with Coptideae.
(3). Comparing with its allies, Calathodes being with out petals, seems to be more
primitive than Trollius. But Calathodes differs from Trollius with R-type chromosomes in having T-type chromosome with x=8 and subterminal centromere. Those charac-
teristics show that it is very similar to the related genera of Thalictroideae. But as
Kurita already pointed out that most speci es of Ranunculus have usually large long
chromosomes but some species have compar ativelly short chromosomes, therefore we
regard T-type and R-type chromosomes appear independently in different subfamilies
of Ranunculaceae. According to Tamura, G alathodes seems to be closely related to
Megaleranthis, because of the resemblance in follicles. But due to lack of cytological
data of the latter genus, the relationship between the two genera still is not clear pen-
ding further studies. From the fact that the morphology and chromosomes of the
Calathodes differs from that of all other genera of the Helleboroideae, we consider
Calathodes may form an independent tribe of its own with a closer relationship withTrollieae. 相似文献
16.
In the work mitotic chromosomes in root-tips of 7 species native to Sichuan Pro-
vince were examined and their karyotypes were analysed based on 7-8 cells at mitotic meta-
phase, using Levan et al.'s (1964) nomenclature. The list of species and origin of the materials
used in this work are provided in the appendix. The micrographs of mitotic metaphase of all
the materials are shown in Plates 1 and 2; the idiograms in Fig. 1, 1-9, and the parameters
of chromosomes are provided in Tables 1-9. All the chromosome countings and karyotypes in
this paper are reported for the first time.
Characteristics of the karyotypes may be summarized as follows:
1. 2n=38 are found in all the materials except A. sichuanensis, which has 3 cytotypes, i.e,
2n=38+5B, 2n=38+lB and 2n=38+OB (Plate 2, 1-2, Fig. 1, 5-6).
2. The karyotypes are of two major types: the karyotype of A. flaviflora falls into 3C in
Stebbins's (1958, 197l) classification of karyotypes and those of all the other species into 2C.
The two types are also different from each other in the number of large and medium-sized
chromosomes pairs and morphology of the first pair of chromosomes (compare Plate 2, 5, Fig.
1, 9 with the other micrographs and idiograms).A. flaviflora with the karyotype 3C also differs
from the other species in a series of gross morphological characters: the species is of a yellow and
campanulate corolla.
3. The species with caespitose leaves (A. caespitosa and A. omeiensis) have essentially the
same karyotype, which is rather different from those of the species with scattered leaves. There
are two pairs of small sm chromosomes (arm ratio ≥1.90) in the former karyotype (Tables 1
and 3), but all the small chromosomes are m or sm with arm ratio <1.80 in the latter karyotypes. 相似文献
17.
From standpoint of floristic division, Sichuan is located in the middle part
of Eastern Asiatic Region (Takhtajan 1978) or is the area where Sino-Himalayan Forest
Subkingdom and Sino-Japan Forest Subkingdom meet (wu 1979). Here exist many so-
called Arcto-Tertiary elements and newly originated species or races. In order to bring
the light the origin and differentiation of Eastern Asiatic elements, cytological investi-
gation on plants of this region are very significant. The materials of the following 5
species were collected on Mt. Emei in Sichuan Province. Voucher specimens are kept in CDBI.
1. Toricellia angulata Oliver var. intermedia (Harms) Hu
PMC meiotic examination revealed n = 12 at diakinesis (Pl. I fig. 9)
Toricellia, consisting of 2 spp., is endemic to Eastern Asiatic Region. Based on
our result along with the report of Toricellia tiliifolia (Wall.) DC. (2n=24) by Kuro-
sawa (1977), we argue that the basic chromosome number of Toricellia is 12. Many
authors, such as Airy-Shaw (1973), Dahlgren (1975, 1977), Takhtajan (1969, 1980),
Thorne (1983), have adopted Hu’s (1934) treatment erecting it as a monotypic family
Toricelliaceae. Its systematic position, whether closer to Cornaceae than to Araliaceae
or vice versa, has been in dispute. Cytologically it seems closer to Araliaceae, as shown
anatomically (Lodriguez 1971), because the basic chromosome number of Cornaceae s.
1. is x=11, 9, 8 (Kurosawa 1977), whereas that of Araliaceae is 12 (Raven 1975).
2. Cardiocrinum giganteum (Wall.) Makino
Somatic chromosome number, 2n=24 was determined from root-tip cells (Ph. I. fig.
8).
Cardiocrinum (Endl.) Lindl., consisting of 3 spp., is endemic to Eastern Asiatic
Region. C. giganteum (Wall.) Makino is distributed from Himalayan region to S. W.
China. The present report is in accord with the number reported by Kurosawa (1966)
who got the material from Darjeeling of India. However the karyotype of the present
plant is slightly different from that given by Kurosawa. In the present material, the
satellites of the 1st. pair of chromosomes and the short arms of llst. pair of chromoso-
mes are visibly longer than those of Kurosawa’s drawing (fig. 1, 2) The plants from
Yunnan, Sichuan and Hubei Provinces, named as C. giganteum var. yunnanense (Leit-
chtlin ex Elwes) Stearn, differ slightly from those of Himalayan region also in outer
morphological characters. The taxon needs both cytological and taxonomical further
studies.
3. Disporum cantoniense (Lour.) Merr.
PMC meiotic examination revealed n=8 at diakinesis (Pl. I. fig. 6)
This species is widely distributed from Himalayan region through Indo-China to
our Taiwan Province and Indonesia. Three cytotypes (2n=14, 16, 30) were reported for
the taxon including its variety, var. parviflorum (Wall) Hara, by various authors (Ha-
segawa 1932, Mehra and Pathamia 1960, Kurosawa 1966, 1971 Mehra and Sachdeva
1976a). Some authors consider D. pullum Salisb. and D. calcaratum D. Don as synonyms
of D. cantoniense. So D. cantoniense may be a species aggregate with different extreme
races. Sen (1973a, b.) reports that the somatic chromosome numbers of D. pullum
and D. calcaratum from Eastern Himalayan region are 14, 16, 28, 30, 32. He also
discovered that chromosome alterations in species of Disporum involve not only the num-
ber but the structure as well. He found that in species of Liliaceae where the reproduc-
tion is mainly vegetative, polysomaty often occurs. In China we have not only D. can-
toniense and D. calcaratum but also D. brachystomon Wang et Tang which is similar
to D. cantoniense var. parviflorum (Wall.) Hara. These taxa need further critical
studies.
4. Paris fargesii Franch.
PMC meiotic examination revealed n=5+2B (Voucher no. 112) or n=5 (Voucher
no. 62) at MI and AI (Pl. I. fig. 1. 4. 5.). This is the first report for the species. A
bridge and a fragment were also observed at AI.
Paris polyphylla Smith is extraordinarily polymorphic species. Hara (1969) re-
gards all chinese extreme forms, such as P. fargesii Franch., P. violacea Lévl., P. pube-
scens (Hand. -Mzt.) Wang et Tang, etc. as infraspecific taxa of P. polyphylla. Need-
less to say, the various races of P. polyphylla Smith in China need further critical stu-
dies and are good material for further study to understand the speciation.
5. Reineckia carnea(Andr.) Kunth
Reineckia is a monotypic genus endemic to Eastern Asiatic Region. In the present
material somatic chromosome number in root-tip cells is determined as 2n=38 (Pl. I. fig.
7). According to the terminology defined by Levan et al., the karyotype formula is
2n=28 m+10 sm. The length of chromosomes varies from 14.28 μ to 5.5 μ. The idiogram
given here (fig. 3) is nearly the same as that presented by Hsu et Li (1984). The same
number has been previously reported by several authors, Noguchi (1936), Satô (1942),
Therman (1956). The karyotype is relatively symmetrical (2B, accorling to the classi-fication of stebbins 1971) in accord with the opinion of Therman (1956). 相似文献
18.
19.
The present paper deals mainly with the karyotype analysis of five
materials in Angelica dahurica collected in Yanbian of Jilin, Anguo of Hebei, Yuxian of
Henan, Hangzhou of Zhejiang and Suining of Sichuan. They are under the names
“Dongbeidahuo”, “Qibaizhi”, “Yubaizhi”, ”Hangbaizhi” and “Chuanbaizhi” respe-
ctively. Among then “Dongbeidahuo” is a wild plant, which occurs in northeastern
China, and the others are cultivated as important crude drugs in some provinces. “Qi-
Baizhi” and “Yubaizhi” have been identified as conspecific with the wild Baizhi-“Do-
Ngbeidahuo” (A. dahurica) according to the external morphological features, whereas the
other cultivated ones, “Hangbaizhi” and “Chuanbaizhi”, treated as a variety (A. dahu-
rica var. formosana).
The results of karyotype analysis are shown in Plate 1, 2, with the formula 2n=22
=12 m+2 mSAT+4sm+4st. The karyotypes described here are constantly characterized by
satellites attached to the fourth pair of metacentric chromosomes and differ from the pu-
blished reports on the other species of the genus. It is reasonable to say that the five
materials collectively named “Baizhi” are taxonomically closely related to each other
and could be regarded as conspecific. Since the second chromosome pair is submetacen-
tric in “Dongbeidahuo”, it may be justifiable to separate the wild plant from the cul-
tivated ones and treat them as two separate varieties. 相似文献
20.
《内江科技》2018,(4):26-27
目的:建立了测定注射用头孢西酮钠中残留溶剂甲醇、丙酮、异丙醇、乙腈和二氯甲烷的顶空气相色谱方法。方法:采用氢火焰离子化检测器,以N,N-二甲基甲酰胺和水(1:1)为样品溶剂,通过对色谱条件优化,建立了以DB-264毛细管柱为分析柱、检测器温度为250℃,进样口温度为200℃,以丁酮为内标对照的残留溶剂测定方法。结果:5种残留溶剂在各自的浓度范围内呈现良好的线性关系(r~2=0.9991~0.9998,n=7),最低检出限范围为0.3655μg/mL~0.7422μg/mL;平均加样回收率为98.1%~100.8%,RSD为1.9%~2.6%,n=3。结论:该方法的检测灵敏度高、精密度好、准确度高、线性关系良好,能够满足对注射用头孢西酮钠质量的控制要求。 相似文献