993 resultados para 230.0230
Resumo:
Geographic and vertical variations of size-fractionated (0.2-1 mu m, 1-10 mu m, and >10 mu m) Chlorophyll a (Chl.a) concentration, cyanobacteria abundance and heterotrophic bacteria abundance were investigated at 13 stations from 4 degrees S, 160 degrees W to 30 degrees N, 140 degrees E in November 1993. The results indicated a geographic distribution pattern of these parameters with instances of high values occurring in the equatorial region and offshore areas, and with instance of low values occurring in the oligotrophic regions where nutrients were almost undetectable. Cyanobacteria showed the highest geographic variation (ranging from 27x10(3) to 16,582x10(3) cell l(-1)), followed by Chl.a (ranging from 0.048 to 0.178 mu g l(-1)), and heterotrophic bacteria (ranging from 2.84x10(3) to 6.50 x 10(5) cell l(-1)). Positive correlations were observed between nutrients and Chl.a abundance. Correspondences of cyanobacteria and heterotrophic bacteria abundances to nutrients were less significant than that of Chl.a. The total Chl.a was accounted for 1.0-30.9%, 35.9-53.7%, and 28.1-57.3% by the >10 mu m, 1-10 mu m and 0.2-1 mu m fractions respectively. Correlation between size-fractionated Chl.a and nutrients suggest that the larger the cell size, the more nutrient-dependent growth and production of the organism. The ratio of pheophytin to chlorophyll implys that more than half of the > 10 mu m and about one third of the 1-10 mu m pigment-containing particles in the oligotrophic region were non-living fragments, while most of the 1-10 mu m fraction was living cells. In the depth profiles, cyanobacteria were distributed mainly in the surface layer, whereas heterotrophic bacteria were abundant from surface to below the euphotic zone. Chl.a peaked at the surface layer (0-20 m) in the equatorial area and at the nitracline (75-100 m) in the oligotrophic regions. Cyanobacteria were not the principle component of the picoplankton. The carbon biomass ratio of heterotroph to phytoplankton was greater than 1 in the eutrophic area and lower than 1 in oligotrophic waters.
Resumo:
以野外样地调查和室内分析法研究了三江源区高寒小嵩草草甸不同退化演替阶段群落中土壤有机碳和微生物量碳的变化.结果表明,放牧活动明显地影响了土壤有机碳和微生物量碳的含量.不同退化演替阶段期间,高寒小嵩草草甸土壤有机碳、微生物量碳含量在0~10 cm土层明显较高,且随着退化程度的加剧,分布在0~40 cm土层的土壤有机碳、微生物量碳含量明显降低;不同退化演替阶段,高寒小嵩草草甸由于家畜过度的啃食与践踏,不仅使得植物群落发生了逆向演替,而且土壤的肥力水平显著地下降,土壤向退化方向发展;高寒草甸的退化将使土壤有机质大量流失,氮素损失严重.随着退化演替过程的进行,高寒草甸土壤质量和土壤营养的持续供给能力逐渐退化,土壤有机碳和土壤微生物量碳含量也随放牧强度增加而迅速降低;相关分析表明,土壤有机碳和土壤微生物量碳与土壤含水量、土壤有机质、土壤速效氮呈显著正相关关系(P<0.05),说明土壤微生物量碳可作为衡量土壤有机碳变化的敏感指标,而土壤有机碳和微生物量碳含量可作为衡量土壤肥力和土壤质量变化的重要指标.
Resumo:
依据涡度相关系统连续观测的2005年CO_2通量数据,对青藏高原东北隅的高寒湿地生态系统源/汇功能及其部分环境影响因素进行了分析。结果表明,高寒湿地生态系统为明显的碳源,在植物生长季(5-9月份)吸收230.16 gCO_2•m~(-2),非生长季(1-4月份及10-12月份)释放546.18 gCO_2•m~(-2),其中净排放最高在5月份,为181.49 gCO_2•m~(-2),净吸收最高在8月份,为189.69 g CO_2•m~(-2),年释放量为316.02 gCO_2•m~(-2)。在平均日变化中,最大吸收值出现在7月份12:00,为(0.45±0.0012)mgCO_2•m~(-2)•s~(-1),最大排放速率出现在8月份0:00,为(0.22±0.0090)mgCO_2•m~(-2)•s~(-1)。生长季中6-9月份表现为明显的单峰型日变化,非生长季的变化幅度较小。净生态系统交换量(NEE)和生态系统总初级生产力(GPP)与气温、空气水气饱和亏和地表反射率等环境因素呈现相似的相关性,与地上生物量和群落叶面积指数则为线性负相关,生态系统呼吸(Res)则与上述因子的相关性呈现相反的趋势。
Resumo:
利用2004年微气象观测资料,分析了海北高寒湿地长、短波辐射以及地表反射率(A)和光合有效辐射(PAR)占太阳总辐射(DR)比例(η)的变化特征。结果表明,海北高寒湿地长、短波辐射均具有明显的季节变化。DR在12月最低,4月最高。PAR在12月最低,7月最高。受下垫面性质影响,反射辐射(UR)和A在1~2月明显大于其他季节,7~10月小,A在植物生长季节的5~9月平均值为0.172,年平均值为0.299。地面长波辐射(DLR)、大气逆辐射(ULR)和净辐射(Rn)的最低值均出现在1月,最大值出现时期则不同,DLR与Rn均出现在6月,而ULR出现在8月。地面有效辐射(ELR)无明显的季节变化。叩的季节变化比较弱,7月最高值为0.434,1月最低值为0.316,年平均值为0.40。
Resumo:
海北高寒矮嵩草草甸区植被下的草毡寒冻雏形土属季节性冻土, 因温度低, 冻土在年内的每个月均可发生. 一般在11月中旬可形成稳定的季节冻结层, 至翌年3~4月冻土层厚度最大可达230 cm. 从3月下旬到4月中旬开始, 土壤开始消融, 至6月下旬到7月上旬冻土全部消失. 分析发现, 季节冻土在高寒草甸植被生产力形成过程中有着积极的影响作用, 主要表现在: 1)季节冻土的存在和维持将给高寒植物生长提供良好的土壤水分, 对植物初期营养生长发育有利, 可弥补春夏之交时降水不足所引起的干旱胁迫影响; 2)季节冻土的长时间维持, 有利于植物残体和土壤有机质留存于土壤, 并随土壤冻结和融化过程发生迁移, 可提高土壤肥力; 3)较高的土壤水分有利于土壤胡敏酸的形成, 可保证植物生长所需的其它有机元素的供给; 4)冻土层所形成较高的土壤水分使土体热容量加大, 从而调节因气候异常波动引起的土壤温度变化; 5)季节冻土的变化对植物地上年生产量形成有一定的影响作用, 表现出从10月或11月开始, 土壤冻结速率快, 对提高植物地上年生产量有利. 这也证实, 在未来气候变暖的趋势下, 土壤有机质将加快分解速度, 土壤水分因受温度升高 , 冻结期缩短, 其贮存能力降低; 受温度升高的影响, 地表蒸发能力加大, 若降水仍保持目前的水平, 土壤水分将明显减少, 将导致高寒草甸植被生产力有下降的可能.
Resumo:
采用两两互作实验并以尿标记来确定共居至成年的2雄性根田鼠同胞在行为竞争上的差异,之后在行为选择箱中分别观察它们对来自熟悉和陌生同性个体的新鲜尿气味的行为反应,以确定气味识别差异.结果表明:①雄性根田鼠两两互作时,尿标记的多少可以作为判断其社会等级的标准;②从属鼠对熟悉气味存在明显偏好,其对熟悉气味的访问时间、接近频次和自我修饰频次都显著高于陌生气味;③优势鼠则优先访问陌生气味,其对陌生气味的访问时间、嗅舔频次、嗅舔时间、自我修饰及反标记均显著高于熟悉气味;④对于陌生气味,优势鼠和从属鼠之间存在明显不同的行为反应模式.本实验结果提示,雄性根田鼠对同性尿气味识别的差异以及对陌生气味的行为反应,可能暗含着其领域防卫的信息.
Resumo:
采用静态箱-气相色谱法,对高寒矮嵩草草甸植被-土壤系统CO2释放特征研究结果表明:3个处理(FC、FJ、FL)CO2释放速率具有明显的日变化规律,日最大释放速率出现在13:00左右,最小释放速率在4:00前后,且白天的释放速率均大于夜间;CO2释放速率也具有明显的季节变化特征,植物生长期释放速率明显高于枯黄期,且均表现为正排放;在整个观测期间(6月30日~1月28日)CO2平均释放速率依次为FC>FJ>FL,矮嵩草草甸植物-土壤系统CO2释放速率为438.34±264.12mg/(m2•h)(FC),土壤呼吸速率为313.20±189.74 mg/(m2•h)(FJ),土壤微生物呼吸速率为230.34±145.46mg/(m2•h)(FL),植物根系呼吸占土壤呼吸的26.5%.植物、植物根系以及土壤微生物CO2释放速率与土壤5 cm温度呈极显著正相关关系,相关系数分别为0.858、0.628和0.672(P<0.01).整个系统呼吸、土壤呼吸与土壤5 cm温度可拟和为一指数方程,方程为y=168.03e0.10x86x(R2=0.8783)和y=149.69e0.0745x(R2=0.8189).
Resumo:
2001~2002年从海北高寒草甸生态系统采集土样,用不同方法从中分离放线菌300余株,根据其形态和分类特征,分别归入小单孢菌属(Micromonospora)、诺卡氏菌属(Nocardia)、糖多孢菌属(Saccharopolyspora)、原小单孢菌属(Promicromonospora)和链霉菌属(Streptomyces),并将链霉菌归入7个类群.同时对230株中温菌和110株低温菌的部分酶活性及其对真菌和细菌的拮抗性进行了测定,发现链霉菌不仅具有许多酶活性,而且对真菌和细菌有拮抗性.
Resumo:
Six domestic yaks aged 6 years, comprising three culling male and three culling female yaks, from the Qinghai Lake area and three male semi-wild yaks aged 6 months from Datong Yak Farm were used to detect the levels of amino acids, mineral elements, residual heavy metals and pesticides in yak meat. The results showed that there was little difference in amino acid levels for different types of yak by age and sex. The meat of the adult male yak was 7.35 mg/kg higher in calcium (P < 0.05) and 124 mg/kg higher in phosphorus (P < 0.01) than that of the adult female yak. There was an obvious difference in zinc content, and there was also a significant difference for copper and sulfur between adult male and female yaks (P < 0.01). Iron was 8.85 mg/kg higher in semi-wild yaks than in domestic yaks, but there were no differences for other minerals. The levels of residual heavy metals and residual pesticides were well within those allowed by the National Standard of China. Furthermore, the data showed that introducing wild yak's blood did not result in a quality change in the domestic yak meat. Yak meat from Qinghai Plateau has the characteristics of being non-polluted and rich in amino acids in comparison with local yellow cattle meat.
Resumo:
The present study was conducted to determine the effects of supplementary feeds, oat hay (OH), highland barley straw (HBS) and multi-nutrient blocks supplementation (UMMB) on reducing liveweight losses of both yak cows and calves grazed on low quality pastures during cold season. The trials of OH and HBS supplementation were conducted by using completely random design on 104 yak cows between 6 and 12 years of age as the following treatments: pure grazing (41 animals, body weight 230 67 kg) as control (CK); grazing+1.5 kg DM of OH per head daily (30 animals, body weight 216 28 kg); gazing. 1.5 kg DM of HBS per head daily (33 animals, body weight 221 34 kg). The trial of UMMB was conducted on three types of yaks, 1-year calves (8-12 months old, body weight 61.1 6.9 kg), 2-year calves (18-24 months old, 98.0 11.3 kg) and yak cows (164.5 27.1 (S.D.) kg) with 20 animals in control group (CK) and 20 animals in supplement group for each type by using completely random design as the following treatments: pure grazing for CK group; grazing+ 150, 250 and 500 g UMMB per day averagely for 1-year calf, 2-year calf and cow at night. The results indicate that the animals supplemented with oat hay received body weight gain (32 20.7 g day(-1)), while those supplemented with highland barley straw still suffered from body weight loss (-56.7 39.3 a day(-1)); UMMB supplementation can decrease the body weight loss by 109.7%, 86.6% and 63.4% for the 1-year calves, 2-year calves and yak cows, respectively, as compared with pure grazing. Around US$1.60 output can be achieved on the basis of US$1 input for UMMB supplementation in the farming systems of the 1-year calves, 2-year calves and yak cows, while US$1 input can produce US$1.55 and 1.14 output for OH and FIBS supplementations, respectively, in yak cows' farming system. It can be preliminary concluded that UMMB supplementation was the most economic way to alleviate body weight loss of grazing yaks over cold season, and the higher productive returns were obtained from OH supplementation for grazing yak cows during winter/spring months. © 2004 Elsevier B.V All rights reserved.
Resumo:
本文主要研究角点检测算法和图像的匹配算法。角点是目标轮廓上具有高曲率的点,它可以较好的描述目标的特征。角点检测技术在计算机视觉和图像理解等领域应用很广,例如运动跟踪、目标识别、立体视觉等。角点检测技术被广泛应用的原因在于:角点包含丰富的图像信息,能够对视觉处理提供足够的约束,极大地提高运算速度,在图像之间进行可靠的匹配。 本文首先介绍了一些经典的基于几何特征的角点检测算法。随后本文详细描述了SUSAN算法,并针对其不足提出了一种改进算法。算法的仿真实验结果验证:该改进算法在性能上较原算法有很大提高。计算机视觉和图像处理中另一个重要的研究内容是图像的匹配,它的应用领域也很广泛。为了利用前文的角点提取结果,本文选取了Chang的点模式识别方法来完成图像匹配,算法的匹配仿真实验结果验证了算法的有效性。 本文在最后的章节中尝试了整套算法的硬件实现,硬件仿真的平台是基于DSP和FPGA的。结果证明,所设计的系统具有较好的跟踪能力和抗干扰能力。
Resumo:
利用基于无色卡尔曼滤波(UnscentedKalmanFilter,UKF)的状态和参数联合估计方法对移动机器人进行在线主动建模,基于该主动模型的逆动力学控制方法,实现了移动机器人对其自身不确定因素的自主性.在针对全方位移动机器人的仿真实验中,验证了UKF对时变的状态和参数的收敛性和跟踪能力,并给出了不确定界.基于主动建模的逆动力学控制方法与常值PID控制方法的比较结果,验证了该方法的有效性.
Resumo:
大文以大连港DP-CIMS资管理系统开发为背景,根据港航运输的特点,利用供应链管协调机制与方法,采用CORBA面向对象技术,开展了基于港航运输的供应链管理模设计与实施技术研究,提出了适合企业的供应链管理总体功能的结构框架,并着手在供应链管理系统网络环境下进行模型建立与开发。
Resumo:
The Qinghai-Tibet Plateau lies in the place of the continent-continent collision between Indian and Eurasian plates. Because of their interaction the shallow and deep structures are very complicated. The force system forming the tectonic patterns and driving tectonic movements is effected together by the deep part of the lithosphere and the asthenosphere. It is important to study the 3-D velocity structures, the spheres and layers structures, material properties and states of the lithosphere and the asthenosphere for getting knowledge of their formation and evolution, dynamic process, layers coupling and exchange of material and energy. Based on the Rayleigh wave dispersion theory, we study the 3-D velocity structures, the depths of interfaces and thicknesses of different layers, including the crust, the lithosphere and the asthenosphere, the lithosphere-asthenosphere system in the Qinghai-Tibet Plateau and its adjacent areas. The following tasks include: (1)The digital seismic records of 221 seismic events have been collected, whose magnitudes are larger than 5.0 over the Qinghai-Tibet Plateau and its adjacent areas. These records come from 31 digital seismic stations of GSN , CDSN、NCDSN and part of Indian stations. After making instrument response calibration and filtering, group velocities of fundamental mode of Rayleigh waves are measured using the frequency-time analysis (FTAN) to get the observed dispersions. Furthermore, we strike cluster average for those similar ray paths. Finally, 819 dispersion curves (8-150s) are ready for dispersion inversion. (2)From these dispersion curves, pure dispersion data in 2°×2° cells of the areas (18°N-42°N, 70°E-106°E) are calculated by using function expansion method, proposed by Yanovskaya. The average initial model has been constructed by taking account of global AK135 model along with geodetic, geological, geophysical, receiving function and wide-angle reflection data. Then, initial S-wave velocity structures of the crust and upper mantle in the research areas have been obtained by using linear inversion (SVD) method. (3)Taking the results of the linear inversion as the initial model, we simultaneously invert the S wave velocities and thicknesses by using non-linear inversion (improved Simulated Annealing algorithm). Moreover, during the temperature dropping the variable-scale models are used. Comparing with the linear results, the spheres and layers by the non-linear inversion can be recognized better from the velocity value and offset. (4)The Moho discontinuity and top interface of the asthenosphere are recognized from the velocity value and offset of the layers. The thicknesses of the crust, lithosphere and asthenosphere are gained. These thicknesses are helpful to studying the structural differentia between the Qinghai-Tibet Plateau and its adjacent areas and among geologic units of the plateau. The results of the inversion will provide deep geophysical evidences for studying deep dynamical mechanism and exploring metal mineral resource and oil and gas resources. The following conclusions are reached by the distributions of the S wave velocities and thicknesses of the crust, lithosphere and asthenosphere, combining with previous researches. (1)The crust is very thick in the Qinghai-Tibet Plateau, varying from 60 km to 80 km. The lithospheric thickness in the Qinghai-Tibet Plateau is thinner (130-160 km) than its adjacent areas. Its asthenosphere is relatively thicker, varies from 150 km to 230 km, and the thickest area lies in the western Qiangtang. India located in south of Main Boundary thrust has a thinner crust (32-38 km), a thicker lithosphere of about 190 km and a rather thin asthenosphere of only 60 km. Sichuan and Tarim basins have the crust thickness less than 50km. Their lithospheres are thicker than the Qinghai-Tibet Plateau, and their asthenospheres are thinner. (2)The S-wave velocity variation pattern in the lithosphere-asthenosphere system has band-belted distribution along east-westward. These variations correlate with geology structures sketched by sutures and major faults. These sutures include Main Boundary thrust (MBT), Yarlung-Zangbo River suture (YZS), Bangong Lake-Nujiang suture (BNS), Jinshajiang suture (JSJS), Kunlun edge suture (KL). In the velocity maps of the upper and middle crust, these sutures can be sketched. In velocity maps of 250-300 km depth, MBT, BNS and JSJS can be sketched. In maps of the crustal thickness, the lithospheric thickness and the asthenospheric thickness, these sutures can be still sketched. In particular, MBT can be obviously resolved in these velocity maps and thickness maps. (3)Since the collision between India and Eurasian plate, the “loss” of surface material arising from crustal shortening is caused not only by crustal thickening but also by lateral extrusion material. The source of lateral extrusion lies in the Qiangtang block. These materials extrude along the JSJS and BNS with both rotation and dispersion in Daguaiwan. Finally, it extends toward southeast direction. (4)There is the crust-mantle transition zone of no distinct velocity jump in the lithosphere beneath the Qiangtang Terrane. It has thinner lithosphere and developed thicker asthenosphere. It implies that the crust-mantle transition zone of partial melting is connected with the developed asthenosphere. The underplating of asthenosphere may thin the lithosphere. This buoyancy might be the main mechanism and deep dynamics of the uplift of the Qinghai-Tibet hinterland. At the same time, the transport of hot material with low velocity intrudes into the upper mantle and the lower crust along cracks and faults forming the crust-mantle transition zone.
Resumo:
The Beishan orogenic collage locates at the triple-joint among Xinjiang, Gansu, and Inner Mongolia Provinces, at which the Siberian, Tarim and North China plates join together. It also occupies the central segment of the southern Central Asian Orogenic Belt (CAOB). The main study area in the present suty focused on the southwest part of the Beishan Mountain, which can be subdivided into four units southernward, the Mazhongshan continental block, Huaniushan Arc, Liuyuan suture zone and Shibanshan-Daqishan Arc. 1. The Huaniushan Arc was formed by northernward dipping subduction from the Orcovician to Permian, in which volcanic rocks ranging from basic to acidic with island arc affinity were widely developed. The granitiod intrusions become smaller and younger southward, whichs indicates a southward rollback of slab. The granitiod intrusions are mainly composed of I type granites, and their geochemical compositions suggest that they have affinities of island arc settings. In the early Paleozoic(440Ma-390Ma). The Shibanshan-Daqishan Arc, however, were produced in the southernward dipping subduction system from Carboniferous to Permian. Volcanic rocks from basic to acidic rocks are typical calcic-alkaline rocks. The granitiod intrusions become smaller and younger northernward, indicating subdution with a northernward rollback. The granitiod intrusions mainly consist of I-type granites, of which geochemical data support they belong to island arc granite. 2. Two series of adakite intrusions and eruptive rocks have been discovered in the southern margin of the Huaniushan Island Arc. The older series formed during Silurian (441.7±2.5Ma) are gneiss granitoid. These adakite granites intruded the early Paleozoic Liuyuan accretionary complex, and have the same age as most of the granite intrusions in the Huanniushan Arc. Their geochemical compostions demonstrate that they were derived from partial melting of the subudcted oceanic slab. These characteristics indicate a young oceanic crust subduction in the early Paleozoic. The late stage adakites with compositons of dacites associate with Nb-enriched basalts, and island arc basalts and dacites. Their geochemistries demonstrate that the adakites are the products of subducted slab melts, whereas the Nb-enriched basalt is products of the mantle wedge which have metasomatized by adakite melts. Such a association indicates the existences of a young ocean slab subduction. 3. The Liuyuan suture zone is composed of late Paleozoic ophiolites and two series of accretionary complexes with age of early Paleozoic. The early Paleozoic accretionary complex extensively intruded by early Palozioc granites is composed of metamorphic clastics, marble, flysch, various metamorphic igneous rocks (ultramafic, mafic and dacite), and eclogite blocks, which are connected by faults. The original compositions of the rocks in this complex are highly varied, including MORB, E-MORB, arc rocks. Geochronological study indicates that they were formed during the Silurian (420.9±2.5Ma and 421.1±4.3Ma). Large-scale granitiods intruded in the accretionary complex suggest a fast growth effect at the south margin of the Huaniushan arc. During late Paleozoic, island arc were developed on this accretionary complex. The late Paleozoic ophiolite has an age of early Permian (285.7±2.2Ma), in which the rock assemblage includes ultra-mafic, gabbros, gabbros veins, massive basalts, pillow basalt, basaltic clastic breccias, and thin layer tuff, with chert on the top.These igneous rocks have both arc and MORB affinities, indicating their belonging to SSZ type ophiolite. Therefore, oceanic basins area were still existed in the Liuyuan area in the early Permian. 4. The mafic-ultramafic complexes are distributed along major faults, and composed of zoned cumulate rocks, in which peridotites are surrounded by pyroxenite, hornblendites, gabbros norite and diorite outward. They have island-arc affinities and are consistent with typical Alaska-type mafic-ultramafic complexes. The geochronological results indicate that they were formed in the early Permian. 5. The Liuyuan A-type granite were formed under post-collisional settings during the late Triassic (230.9±2.5Ma), indicating the persistence of orogenic process till the late Triassic in the study area. Geochronological results suggested that A-type granites become younger southward from the Wulungu A-type granite belt to Liuyuan A-type granite belt, which is in good agreement with the accretionary direction of the CAOB in this area, which indicate that the Liuyuan suture is the final sture of the Paleo-Asin Ocean. 6. Structural geological evidence demonstrate the W-E spreading of main tectonic terrenes. These terrenes had mainly underwent through S-N direction contraction and NE strike-faulting. The study area had experienced a S-N direction compression after the Permian, indicating a collisional event after the Permian. Based on the evidene from sedimentary geology, paleontology, and geomagnetism, our studies indicate that the orogenic process can be subdivided into five stages: (1) the pre-orogenic stage occurred before the Ordovicain; (2) the subduction orogenic stage occurred from the Orcovician to the Permian; (3) the collisional orogenic stage occurred from the late Permian to the late Triassic; (4) the post-collision stage occurred after the Triassic. The Liuyuan areas have a long and complex tectonic evolutional history, and the Liuyuan suture zone is one of the most important sutures. It is the finally suture zone of the paleo-Asian ocean in the Beishan area.