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1.
本文利用Krasnoselskii不动点定理,考虑了状态依赖时滞性微分方程x′(t) = &;#8722;A(t, x(t))x(t) + B(x(t))F(x(t &;#8722; (t, x(t))))正周期解的存在性, 得到了该方程存在与不存在正周期解的充分条件. 相似文献
2.
在高分子构象统计中,表征分子尺寸的参数有和。对于无规行走链,_0/_0值仅与P有关,与高分子链本身的结构无关。对于自避无规行走链,采用Monte Carlo模拟方法计算了/值,发现/也仅与P有关,并可用经验公式/ 相似文献
3.
1 收集资料 在正式施工前应具备必要的下列工程资料: (1)建筑物场地工程地质和必要的水位地质资料; (2)桩基施工图及图纸会审纪要; (3)建筑场地和邻近区域的地下管线(管道、电缆)资料; (4)主要施工机械及其配套设备的技术性能资料; (5)桩基的施工组织设计或施工方案; (6)桩基钢筋砼所用建材(水泥、砂、石、钢筋)的质检报告. 相似文献
4.
21世纪中国极端气温指数变化情况预估 总被引:20,自引:6,他引:20
利用政府间气候变化委员会资料中心的模式预测结果(IPCC-AR4),分析了在高(SRES A2)、中(SRES A1B)、低(SRES B1)3种不同的排放情景下中国未来21 世纪极端气温变化特征。研究结果表明:随着全球变暖,中国区域极端气温指数的变化是一致的增加(减少)趋势。其中霜冻日数和温度年较差呈减少趋势,生长季指数、热浪指数和暖夜指数是增加趋势。在高排放(A2)情景下,中国地区各极端气温指数增加(减少)趋势最明显,低排放(B1)情景下极端气温指数变化趋势最小。在2075年前,极端气温指数在A1B情景下的变化幅度要大于A2情景下的变化,2075年之后,却与之相反。在各极端气温指数中,热浪指数(HWDI)和暖夜指数(TN90)上升趋势最为明显,其次是霜冻日数(FD)和生长季指数, 气温年较差(ETR)变化最小。在空间分布的特征上,极端气温指数基本上保持一致的增加或减少的变化趋势(温度年较差除外),变化基本上是由北向南变化率逐渐增大,其中西北的极端指数变化率高于东北,只有暖夜指数的变化情况有所不同,在西南和华南地区出现了变化的大值区。 相似文献
5.
猕猴桃科的花粉形态及其系统位置的探讨 总被引:3,自引:0,他引:3
张芝玉 《中国科学院研究生院学报》1987,25(1):9-23
本文作者用光学显微镜和扫描电镜(少数种类用透射电镜)对猕猴桃科Actinidia-
ceae(按照Cronquist 1981和Dahlgren 1983的概念)的猕猴桃属Actinidia(15种)、藤山柳
属Clematoclethra(5种)和水东哥属Saurauia(3种)植物的花粉形态进行了观察,并与山茶科
Theaceae(7属9种)和山柳科Clethraceae(1属1种)的花粉进行了对比分析。根据花粉的
资料,并综合分析有关的外部形态、胚胎和化学方面的特征,讨论了猕猴桃科的范围,以及这个
科的系统位置。 相似文献
6.
一、原料(以生产50公斤为例) (1)无水硫酸钠10公斤; (2)碳酸钠5公斤; (以上两种原料均用20目筛子过筛,操作时应戴上口罩) (3)泡花碱10公斤; (4)烷基苯磺酸钠10公斤; 相似文献
7.
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
8.
1、《主要时间序列方法的预测精度》该书1984年4月出版,共310页。由S·Makridakis(法国、欧洲工商管理学院),A·Anderson(澳大利亚、悉尼大学),R·Carbone(加拿大、麦吉尔大学),R·Fildes(英国曼彻斯特商学院)R·Lewandowski(西德)等8人合著。 相似文献
9.
10.
探讨老年人扩张型心肌病 ( DCM)的临床特征并与青年人 DCM进行比较 .通过临床观察对 80例老年人和 140例青年 DCM的临床资料进行对比分析 .结果发现 :( 1)老年组醛固酮值( 30 4 .8± 69.1)较青年组 ( 2 13.3± 54.5,pmol/ L)明显增高 ( P<0 .0 5) ,老年组 T3和 FT3值 ( 0 .78± 0 .2 1,2 .87± 0 .73)较青年组 ( 1.2 6± 0 .33nmol/ L ,3.55± 0 .64pmol/ L )明显降低 (均为 P<0 .0 1) ;( 2 )老年组室性心律失常发生率 ( 61.3% )较青年组 ( 92 .1% )低 ( P<0 .0 1) ;( 3)老年组低血钾、低血镁发生率高 (分别为 51.3%和 2 7.5% ) ,对洋地黄敏感性增加 ,易发生洋地黄中毒( 2 8.8% ) ;( 4 )老年组的病程 [( 11.0± 4 .7)年 ]和平均生存期 [( 6.9± 4 .2 )年 ]均较青年人 [( 5.2±2 .5)和 ( 3.4± 2 .7)年 ]长 (均为 P<0 .0 5) ;( 5)老年组的主要死因是充血性心力衰竭 ( 78.9% ) ,青年组则为恶性心律失常 ( 61.9% ) .结论为老年人 DCM的预后比青年人相对要好 ;老年人 DCM常伴低 T3综合征 ;心力衰竭、电解质失衡及交感神经兴奋是老年人 DCM室性心律失常的主要原因 相似文献
11.
伞形科植物染色体数目报告 总被引:1,自引:0,他引:1
本文报道了伞形科15属24种和交种的染色体数,其中18个种和变种是首次报道。研
究表明, 我国天胡荽属 (Hydrocotyle L.)是伞形科多倍体比较普遍的类群。柴胡属(Bupleu-
rum L.)分别有4、6、7、8等基数,茴芹属(Pimpinella L.)的毛果组(Sect. Tragium)和光
果组(Sect.Tragoselinum)的代表种类的基数分别为9和10,因此,染色体基数可作为深入
研究某些属内种类演化的细胞学资料之一。思茅独活(Heracleum henryi Wolff)的花粉母细 胞在终变期时出现了4体环,说明结构杂合体可能是伞形科种类分化的一个因素。 相似文献
12.
翁若芬 《中国科学院研究生院学报》1990,28(1):27-33
本文报道华东地区30种蕨类植物的染色体数目,其中阔片短肠蕨Allantodia mathewi(Cop.)
Ching n=82, 耳羽短肠蕨A.wichurae(Mett.)Ching n=41,拟粉背蕨Aleuritopteris pseudof-
arinosa Ching n=58,刺头复叶耳蕨Arachniodes exilis(Hance)Ching n=41,斜方复叶耳蕨A.
rhomboides(Wall.) Ching n=41,毛轴假蹄盖蕨Athyriopsis peterseni(Kunze)Ching n=80,
园盖阴石蕨Humata tyermanni Moore n=40, 峨眉茯蕨 Leptogramma scallanii(Christ)Ching
n=36,福建剑蕨 Loxogramme fujianensis Ching n=35,黄腺羽蕨Pleocnemia winitii Holtt.
n=41,紫柄蕨Pseudophegopteris Pyrrhorachis(Kunze)Ching n=62是首次报道。 相似文献
13.
中国绞股蓝属(葫芦科)的研究 总被引:2,自引:0,他引:2
The genus Gynostemma B1. consists of 13 species and 2 varieties in the whole world,
among which 11 species and 2 varieties occur in China. They are distributed in S. Shaanxi
and the southern part of the Yangtze River (including Taiwan province) in China and also
in Korea, Japan, Sri Lanka, India and Malesia. Based on the characters and dehiscence of fruit, the genus Gynostemma B1. may be divided into two subgenera, i.e. Subgen. I. Gynostemma and Subgen. II. Trirostllum (Z. P. Wang et Q. Z. Xie) C. Y. Wu ct S. K. Chen,
comb. nov.
1. Subgenus Gynostemma. The fruits are baccate, globose, 3-umbonate and incorni
culate on the apical side, indehiscent when mature. The style apex in female flower is bifid.
Type of subgenus: Gynostemma pentaphyllum (Thunb.) Mak.
This subgenus contains 8 species and 2 varieties in the world, among which 6 speci-
es and 2 varieties occur in China, i.e.1.G. simplicifolium B1. (Yunnan, Hainan of Guang-
dong); 2. G. laxum (Wall.) Cogn. (S. Yunnan, Hainan of Guangdong and Guangxi); 3.
G. burmanicum King ex Chakr. (Yunnan), 3a. G. burmanicum var. molle C. Y. Wu (Yun-
nan); 4. G. pentaphyllum (Thunb.) Mak. (S. Shaanxi and the soutern area of the Yangtze
River of China), 4a. G. pentaphyllum (Thunb.) Mak. var. dasycarpum C. V. Wu (Yun-
nan); 5. G. pubescens (Gagnep.) C. Y. Wu, st. nov. (Yunnan); 6. G. longipes C. Y. Wu,
sp. nov. (endemic to China: Yunnan, Sichuan, Guizhou, Shaanxi and Guangxi).
2. Subgenus Trirostellum (Z. P. Wang et Q. Z. Xie) C. Y. Wu et S. K. Chen, comb.
nov.——Trirostellum Z. P. Wang et Q. Z. Xie in Acta Phytotaxonomia Sinica 19 (4):
483. 1981, syn. nov. The fruit are capsules, subcampanulate, 3-corniculate on the apical side, dehiscent when mature. The style apex in female flower is luniform and irregularly denticulate at margin, rarely bifid.
Type of subgenus: Gynostemma cardiospermum Cogn. ex Oliv. This subgenus comprises 5 species, which are all endemic to China. 1. G. yixingense (Z. P. Wang et Q. Z. Xie) C. Y. Wu et S. K. Chen (Jiangsu and Zhejiang); 2. G. cardio spermum Cogn. ex Oliv. (Hubei, Shaanxi and Sichuan); 3. G. microspermum C. Y. Wu et S. K. Chen (S. Yunnan); 4. G. aggregatum C. Y. Wu et S. K. Chen (NW. Yunnan); 5. G.laxiflorum C. Y. Wu et S. K. Chen (Anhui). 相似文献
14.
青海湖流域气候变化及其水文效应 总被引:8,自引:0,他引:8
利用青海湖流域内及周边6个气象站近50年来的逐日最高、最低、平均气温和降水量,青海湖水位、面积以及沙柳河和布哈河逐月径流资料分析了该流域的气候变化及其水文效应。结论认为:青海湖流域近年来最高气温以(0.29±0.17)℃/10年的速度增加(p>0.05),最低气温以(0.55±0.5)℃/10年的速度显著增加(p<0.05),平均气温以(0.28±0.03)℃/10年的速度显著增加(p<0.05),同时,年平均温差以(-0.12±0.02)℃/10年的速度显著减少(p<0.05)。与全球气候变暖相比,青海湖流域气温升高的速度更快。流域各站年降水量和日最大降水量呈增加趋势(p>0.05),降水天数和干旱期变化差异性较大。青海湖水位和面积分别以7.8cm/年和7.4km2/年的速度显著下降(p<0.01)。沙柳河、布哈河年径流量呈略微减少趋势(p>0.1),而且分别在4月~5月和12至次年4月减少趋势显著(p<0.05)。气候变化和水文效应相关分析表明,青海湖水位与流域平均气温呈显著负相关(p<0.01),而水位变化量、沙柳河和布哈河径流量与降水量呈显著正相关(p<0.01)。 相似文献
15.
我国20所高校自然科学学报的统计分析 总被引:5,自引:0,他引:5
对20种高校自然科学学报进行了统计分析.<学报>开本以国际A4为主流,信息量逐年增加.基金论文比例较高(50.85%),平均发文时滞367天.其合著率(90.17%)、引文比率(99.33%)均较高.但合作度(3.04人)偏低,篇均引文(5.65篇)低于国内水平,更低于国外水平.<学报>编辑规范化水平较高,但应致力于缩短发文时滞.有条件的应出版<学报>的英文版,并积极创造条件尽快上网,使<学报>早日走向世界. 相似文献
16.
本文报道了我国黑龙江产桔梗科沙参属的10种1变种的染色体数目和核型,对其中
7种作了减数分裂行为的观察。 其中6种1变种为首次报道,并发现2n=68的4x种。该
属染色体基数多为17(x=17),但Adenophora trachelioides和A.remotiflora的基数为18
(x=18),为该属独特基数。核型的共同特征是:小型,以中部(m)、近中部(sm)着丝点
染色体为主,至少具一对近端着丝点染色体和一对随体染色体。该属染色体的演化处于二种
水平: 数目变化(包括多倍化和非整倍体变化)和结构变异。 多倍化是该属物种形成的主要
途径之一。结合其它性状讨论了这些种的分类,并确立1个四倍体新种(A. amurica)和1个新组合(A.pereskiifolia ssp.alternifolia)。 相似文献
17.
The vegetative characters of Ligusticum chuanxiong Hort. cv. Fuxiong
are described in comparison with L. chuanxiong Hort. and L. sinense Oliv. The chromosome
numbers and karyotypes of the three taxa were studied in root tip cells by Feulgen’s squash
method. Their karyotypes are determined as follows: L. chuanxiong, K(2n)=22=16 m+
4sm+2st (sat); L. chuanxiong cv. Fuxiong, K(2n)=33=24 m+6sm+3st (sat); L. sinen-
se, K(2n)=22=12 m+6sm+2sm (sat)+2st (sat).
The karyotypic similarities are found between L. chuanxiong and its cultivariety, butthe former is a diploid while the latter probably is a homologous triploid. 相似文献
18.
19.
芍药属的研究(1)——国产几个野生种核型的报道 总被引:1,自引:0,他引:1
In the present paper 8 species with 15 populations of the genus Paeonia L. (if P.
papaveracea and P. japonica are recognised as species) were collected from Sichuan, Shaanxi
and Hebei provinces (see the Appendix for detail of the materials). The micrographs of their
somatic metaphase (also Mii in the case of P.veitchii) are shown in Plates 1-4, the karyo-
type formulae, ranges of chromosome length and classification of karyotypes according to Steb-
bins (1971) are shown in Table 5: the idiograms in Figs. 1-2, and the parameters of chromo-
somes in Table 1-4. The essential points are mentioned as follows:
(1) Chromosomes of the various species in the section Modan have so far been examined
and they are all diploid, the two species in the section Onaepia are also diploid, and thus
tetraploids exist only in the section Paeonia.
(2) Chromosomes in the genus Paeonia are relatively stable except for the differentiation
of ploidy. The karyotypes (Table 1-4) show no differences among different taxa in Sect.
Modan and the same can also be said about the taxa in Sect. Paeonia (Table 1). Not only
are the karyotypes very similar, but also among the members within either section have the
same parameters of chromosomes, and, differences, if occur, are not statistically significant.
Between the two sections, however, the situation is different. The arm ratios of the first pairs of
chromosomes in Sect. Modan are 1.53, 1.52 and 1.48 (Table 1), but those in Sect. Paeonia
are 1.12-1.28 (Table 2-4), 95% confidence limits are 1.46-1.60 for the section Modan and
1.07-1.28 (1.21-1.35 only for PB85078) for the section Paeonia, not overlapping, which indi-
cates that the two sections have differentiated in respect of the first pairs of chromosomes.
(3)The population PB85024, which belongs to the P. obovata complex, has a karyotype of
2B (stebbins, 1971), which is a new one in the genus Paeonia. This karyotype is a stable one,
for several individuals in the population are uniform in this respect, which shows that Steb-
bins’ (1971) generalization that all the species in Paeonia have 2A does not hold true.
(4) Three populations of P. obovata complex studied in this work from Sichuan and
Shaanxi are all tetraploids, and one from Hebei is a diploid. From the present work and
the previcus reports, the materials from Japan and Korea, no matter whether flowers are pink
or white, are diploids, those from Heilongjiang Province (with both pink and white flowers)
(Liu Ming-yuan, personal communication) and from Heibei Province (with pink flowers)
in China are also diploids, the one from Sakhalin (pink flowers) is tetraploid, those from
Priamur of the Soviet Union are a tetraploid (with white flowers) and a diploid (with pink
flowers), and those from Shaanxi (the Qinling Range) and western Sichuan (with both pink
and white flowers) are all tetraploids. As far as we have now known, ploidy in this parti-
cular complex is correlated with the geographical distribution: diploids are found in the cen-
tral part, tetraploids occur in the northern limits, and in the south letraploids are the only
cytotype.
(5) The materials of P. mairei from western Sichuan and Shaanxi (the Qinling Range)
are found all to be tetraploids, which shows that two cytotypes, diploid and tetraploid, exist in
this species, but the geographical distribution pattern of these two cytotypes is to be revealed
in the future investigation. 相似文献
20.
国产三角瓣花属(茜草科)订正 总被引:1,自引:0,他引:1
阮云珍 《中国科学院研究生院学报》1988,26(6):443-449
三角瓣花属Prismatomeris Thw.在Hooker(1873)和K.Schumann(1891)的茜草
科分类系统中隶于巴戟族Morindeae Miq.但在 Bremekamp(1966年)的分类系统中,其分类
位置未定。本属的胚根下位,花冠裂片镊合状排列和具针晶等特征与巴戟族相同,但它的花
离生,子房2室,胚珠盾形而着生于子房隔膜上半部等特征则与巴戟族明显不同。 因此,
将本属分立作族并置于Bremekamp所定界的茜草亚科Rubioideae中似乎较合适。 本文还提
供了经挑选的本属10对特征及其分类价值的说明。辨别了两个种:(1)将分布于中国的P.
tetrandra(Roxb.)K.Schum. 修订为 “P.tetrandra (Roxb.) K. Schum. subsp. multiflora
(Ridley,)Y.Z.Ruan”. (2)P. connata Y. Z. Ruan 被记述作新种它的热带新亚种是 P. connata Y. Z. Ruan subsp. hainanensis Y. Z. Ruan。 相似文献