吉林哈尼湖钻孔5000年来的植被演替与气候变化

重建古气候、古环境已成为当今全球变化研究的热点。5000以来是人类有文字记录的历史时期，其气候与植被变化与人类活动十分密切，对这一时期的气候变化的研究，具有重要的理论意义。 植被的状况可以在相当大的程度上反映气候的状况。孢子和花粉由于其个体小、产量高和易于保存而成为植被演替和古气候、古环境研究的重要手段之一。 孢粉组合的变化可以很好地反映植被的演替，吉林地区地层沉积比较稳定，本文选取哈尼湖钻孔360-0cm（5112－0aBP）的沉积物进行孢粉分析，共采取样品85个，平均时间分辨率约为60年。样品中花粉含量非常丰富，种类以乔木为主，其百分含量多在80%以上，最高可达96%，根据花粉组成在钻孔上的变化，结合花粉沉积率进行样品的分析，自下而上可分为4个花粉组合带，进而得出5000年以来该区气候演化大致可分为4个阶段：阶段1（5112－3784aBP），阔叶类乔木占优势，湿生及水生草本比较丰富，气候温暖湿润;阶段2（ 3784 －1380aBP）针叶类乔木占优势，湿生及水生草本消失，气候变凉干;阶段3（ 1380 －994aBP），以松为主的针叶类仍占绝对优势，喜温湿的灌木草本含量持续下降，说明气候继续变冷变干;阶段 4（ 994－0aBP），植物种类比较丰富，湿生植物的沉积率明显增高，气候变的更加湿润。

Rubriflordilactones A and B, two novel bisnortriterpenoids from Schisandra rubriflora and their biological activities

Rubriflordilactones A (1) and B (2), two novel highly unsaturated rearranged bisnortriterpenoids possessing a biosynthetically modified aromatic D-ring, were isolated from the leaves and stems of Schisandra rubriflora. Their structures were established on

The study of biological characteristic and population dynamic of Caspian vimba (Vimba vimba persa), in coastal waters of Caspian Sea (Mazandaran Province)

This study was conducted to determine reproduction characteristics, diet regime, age structure and population dynamics parameters of the vimba vimba persa (Pallas, 1811) in Mazandaran waters of the Caspian Sea, from October 2008 to September 2009. A total of 994 specimens were monthly collected by beach seine and cast net from six fish landings of Ramsar, Tonekabon, Chaloos, Mahmood Abad, Sari and Behshahr. Biometric characters were measured for each specimen at the laboratory. Scales were used for age determination. Sex determination and fecundity were determined. Population dynamic parameters as well as stock assessment including cohort analysis were estimated using FISAT software. The finding showed that the mean of fork length and body weight of the Caspian Vimba were 168.4±2.6 mm and 71.94±32.24 g respectively. Strong correlation was found between these two variables (a= 0.012; b = 3.047; r2 = 0.955). 92 specimens were studied from the fecundity point of view. This species was found to have more abundance in spring (esp. Apr-May). The samples composed of 397(42.6%) male, 537(57.4%) female; Overall sex ratio (M: F =1: 1.35) was significantly different from the expected 1:1 ratio (p ≤0.05). The advanced stages of maturity (4th & 5th) were found in April and May. The highest Gonadosomatic Index in female was in May and the lowest one was in July. This fish is therefore a spring spawner. The maximum absolute and relative fecundities were 34640 and 260.9, respectively; the minimum absolute and relative fecundities were 5400 and 94.5 respectively. The averages of absolute and relative fecundities were 17198±7710 and 171.85±48.8, respectively. Coefficient vacuity index was 59.2% which indicates that this fish is mesophagous. Among of living creature consumes by Caspian Vimba mollusks, 76 arthropods, worms, plants, detritus and fishes were found 32.9% , 26.7% , 13.4% , 17% , 4.4% and 1.6% respectively. The infinite fork lengths were 261 mm for females, 25mm for males and 261 mm for both sexes respectively. For population growth and mortality parameters; K ( 0.28 per year for both sexes, 0.3 per year for males, 0.33 per year for females); t0 ( -0.65 year for both sexes, -0.23 year in females, -0.51 year in males ); Φ' ( 2.28 ); Z ( 0.98 per year ); M ( 0.59 per year); F ( 0.39 per year) and Exploitation coefficient was 0.4. The analysis showed that total biomass and MSY were 1336 and 528.8 tonnes respectively.

云南哀牢山平河黑长臂猿栖息地乔木结构分析

采用样方方法对栖息于云南省哀牢山平河(E 101°17′16.1″,N 24°20′09.5″,海拔2 600 m)的黑长臂猿(Nomascus concolor)栖息地乔木层结构进行了调查.调查中共记录到乔木57种隶属于23科37属;木质藤本植物9种隶属于6科8属.优势科主要为杜鹃花科(Ericaceae)、木兰科(Magnoliaceae)、山茶科(Theaceae)和壳斗科(Fagaceae)植物.主要树种重要值排序表明,露珠杜鹃(Rhododendron irroratum)为该地区最主要的优势种,在各坡位中均有广泛分布.乔木的多样性指数、均匀度指数在沟底明显降低,而乔木1层和2层所占的比例以及木质藤本的平均多度均随着坡位的下降而升高.与其他地区的长臂猿相比,哀牢山黑长臂猿的活动程度较低(10-22 m),果实性食物种类较少.

Micromachining of glassy carbon toolsets for micro embossing applications

Laser micro machining is fast gaining popularity as a method of fabricating micro scale structures. Lasers have been utilised for micro structuring of metals, ceramics and glass composites and with advances in material science, new materials are being developed for micro/nano products used in medical, optical, and chemical industries. Due to its favourable strength to weight ratio and extreme resistance to chemical attack, glassy carbon is a new material that offers many unique properties for micro devices. The laser machining of SIGRADUR® G grade glassy carbon was characterised using a 1065 nm wavelength Ytterbium doped pulsed fiber laser. The laser system has a selection of 25 preset waveforms with optimised peak powers for different pulsing frequencies. The optics provide spot diameter of 40 μm at the focus. The effect of fluence, transverse overlap and pulsing frequency (as waveform) on glassy carbon was investigated. Depth of removal and surface roughness were measured as machining quality indicators. The damage threshold fluence was determined to be 0.29 J/cm2 using a pulsing frequency of 250 kHz and a pulse width of 18 ns (waveform 3). Ablation rates of 17 < V < 300 μm3/pulse were observed within a fluence range of 0.98 < F < 2.98 J/cm2. For the same fluence variation, 0.6 μm to 6.8 μm deep trenches were machined. Trench widths varied from 29 μm at lower fluence to 47 μm at the higher fluence. Square pockets, 1 mm wide, were machined to understand the surface machining or milling. The depth of removal using both waveform 3 and 5 showed positive correlation with fluence, with waveform 5 causing more removal than waveform 3 for the same fluence. Machined depths varied from less than 1 μm to nearly 40 μm. For transverse overlap variation using waveform 3, the best surface finish with Rz = 1.1 μm was obtained for fluence 0.792 J/cm2 for transverse overlap of 1 μm, 6 μm, and 9 μm at machined depths of 22.9 μm, 6.6 μm, and 4.6 μm respectively. For fluence of 1.426 J/cm2, the best surface finish with Rz = 1.2 μm was obtained for transverse overlap of 6 μm, and 9 μm at machined depths of 12.46 μm, and 8.6 μm respectively. The experimental data was compiled as machining charts and utilised for fabricating a micro-embossing glassy carbon master toolsets as a capability demonstration.

鱼腥藻PCC7120外膜的纯化和外膜蛋白的鉴定

国家自然科学基金项目30570022资助

定量评估豢养长江江豚个体间的优势关系

2000年1—4月和2000年4月—2002年4月,分别连续3个月和2年观察了中国科学院水生生物研究所白鱀豚馆6头长江江豚(3雌3雄,8个不同组合群)个体间发生的3种交互关系,即接近—逃开、接近—接触和接近—尾鳍击打。在累计8,162min的观察时间内,共观察到这些交互关系1,685次。本研究将江豚个体间发生的这3种交互关系作为个体间优势关系的指示,并分别给交互双方赋予不同的分值,采用优势比分矩阵方法定量分析了江豚个体之间的优势关系。结果表明江豚群体内存在优势关系。同性别个体之间,优势关系与年龄和饲养时间

武汉东湖主要养殖水域的浮游甲壳动物群落分析

报道了 1 994～ 1 996年武汉东湖水果湖、郭郑湖、汤林湖和后湖 4个主要鱼类养殖水域甲壳动物群落结构变化的调查结果。其目的旨在比较 4个湖区甲壳动物群落结构的差异 ,探讨甲壳动物群落变化与鱼类养殖、水生植物及水体富营养化间的关系。结果表明 ,在东湖 、 站 ,类平均密度明显低于 、 站 ( P<0 .0 5 ) ,而近邻剑水蚤在 3个周年里一直占据桡足类的优势地位。 站从 1 995年 , 站从 1 996年起 ,近邻剑水蚤均取代了广布中剑水蚤成为桡足类的第一优势种。甲壳动物的体长频度分布表明

从时空异质性看东湖富营养化中原生动物的演替

1993-0 8～ 1 994 -0 8,东湖原生动物年均丰度为 59,391 ind./ L,年均生物量为 1 .4 0 mg/ L。从 V站到 0站 ,随着营养水平 ( TSI)增加 ,数量 ( A)和生物量 ( B)显著增加 :Ln A=-58.32 3+1 6.50 3Ln TSI( n=5,r=0 .983,p=0 .0 0 3) ;Ln B=-1 6.84 0 +0 .2 56TSI( n=5,r=0 .996,p<0 .0 0 1 ) ,两者均表现出明显的空间异质性。同时 ,丰度的周年动态模

南极菲尔德斯半岛地区土壤原生动物生态学研究

作者于 1 994年 1 2月至 1 995年 2月设置 1 3个采样站 ,对南极菲尔德斯半岛地区土壤原生动物进行了研究。共观察到原生动物 37种 ,其中 :鞭毛虫 1 1种 ,肉足虫 9种 ,纤毛虫 1 7种 ;优势种为梨波豆虫 ,球波豆虫 ,小滴虫 ,聚滴虫 ,跳侧滴虫 ,磷壳虫和钩刺斜管虫 ;原生动物密度在采样站间的变化范围在 33- 577个 /g干土之间 ,格鲁玻科湖岸边土壤站最低 ,而阿德雷岛苔藓下土壤站最高 ,回归分析表明 :土壤原生动物密度与土壤含水量呈显著性直线相关。