968 resultados para Belt conveyors
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辐射传输研究是贯穿森林生态系统的纽带,太阳辐射为植物的生长发育提供光合能量、适宜的环境温度以及发育信息。一方面,气候变化使到达地面辐射能的质和量发生变化,影响到植被的生长发育,改变森林的结构,而森林结构的变化又会影响林冠内辐射能的分配和质量,这些变化会进一步影响到林下土壤温度,改变森林根系活性以及土壤营养转化的效率;连锁反应的结果有可能会使森林生态系统的生产力发生变化,改变碳素和氮素源库的调节方向,从而反馈影响地球气候系统。另一方面,人类作为生态系统的成员,必然需要森林生态系统为其提供更多的原材料和更好的生态服务功能,如何实现这些目标,就需要人类适度调整干预方式和频度,达到预期的目的。本文在建立适合于川西亚高山森林的叶面积测量技术、光照辐射模型和土壤温度变化模型的基础上,对川西亚高山地带森林生态系统的辐射传输特征进行了分析,并从森林结构的角度探讨了林分内的辐射分布以及对土壤温度的影响。主要成果如下: 1. 提出了一种照相法测量叶面积的方法。通过对摆放在平面上的叶片照相,利用投影变化,把非正射图像转化为正射图像,然后经过计算机图像处理得到每一片叶片的面积、周长、长度、宽度等信息。这种方法可使用户以任意方向和距离拍摄处于平面上的叶片,能同时处理大量的叶片,适于野外离体或活体叶片测量。叶片面积分辨率可调,分辨率可以与常用的激光叶面积仪相近甚至更高,而且叶片图像可以存档查询。 2. 提出一种模拟林内光照变化的模型。利用林冠半球照片,记录视点以上半球内的林冠构件空间分布,作为林冠子模型;天空辐射子模型采用国际照明委员会(CIE)的标准晴天和阴天以及插值模型。该模型能够模拟林下某一位点处的实时光斑变化。 3. 提出一种土壤温度变化模型。把土壤视为具有容量和阻力性质的结构,利用电阻和电容器件构建土壤能量分布模型。外界太阳辐射能经过植被以及其它一些能量分配器后进入土壤,其中有一部分转化为土壤势能,即土壤温度。土壤温度的变化类似于电池的充放电过程。在已知模型参数的情况下,可以从太阳辐射计算土壤温度的变化。在模型参数未知的情况下,通过输入和输出值推算模型的参数,而模型参数中的时间常数与土壤组成和含水量有关,这样就可以知道土壤水分的变化情况。 4. 从王朗亚高山森林典型样地林分结构的测量获得林地三维结构图、树冠形态、叶面积密度等参数,这些参数输入到Brunner (1998)开发的tRAYci 模型中计算出一段时间内林分任意位置处的光照值。与林下辐射计测量值以及半球照片计算结果的比较,该模型基本上能够满足对林分光环境了解的要求。 5. 从川西亚高山森林生产力的角度,探讨了森林生产力研究的方法以及川西地区的研究历史和成果,发现了其中的一些规律和问题,特别是在叶面积测量上,还没有使用标准的叶面积指数定义。综合来看,川西地区针叶林叶面积指数(单位土地面积上植物冠层总叶面积的一半) 应在4-5 之间。降雨丰富的华西雨屏带是川西地区森林生产力最高的地区,而向西北森林生产力逐渐降低。川西地区云冷杉林森林生产力平均约为600 gDM m-2 a-1,但是根据辐射能计算的潜在生产力则达到1800 gDM m-2 a-1。实际与潜在森林生产力的巨大差异说明其它因子对生产力的影响。 6. 王朗亚高山3 个典型森林林分中,白桦林样地(BF) 林下草本以糙野青茅、牛至、紫菀等喜阳性物种为主,林下透光度较高;冷杉林样地(FF) 林下透光度最低,以喜阴性物种水金凤、蟹甲草、囊瓣芹等为主;而云杉林样地(SF)林分林龄最大,林下透光度介于冷杉林和白桦林之间,草本层仍然以喜阴性物种东方草莓、紫花碎米芥、酢浆草等为主。冷杉林和云杉林的灌木层也很丰富,卫矛属、五加属、茶藨子属、忍冬属植物很丰富,而在白桦林则以栒摘要子属、榛子属、鹅耳枥属等植物为主。藓类植物在云杉林中最丰富,并且形成毯状层,其它两个林分则很稀少。3 个样地林分结构与林下光环境有很强的相关性,从光环境特征可以在一定程度上推测林分的结构。各样地单纯从乔木层材积推算的NPP 排列顺序为BF>FF>SF,与林下辐射透射率和林分年龄的顺序相同,暗示辐射对群落演替过程的驱动作用。 7. 用半球照相法测得BF、FF 和SF 3 个样地的有效叶面积指数以SF 样地最高,BF 最低。如果考虑针叶树叶片在小枝上的丛聚分布,利用北方针叶林的数值进行校正,则SF 样地LAI 显著增加(达到89%),其它样地的LAI 基本不变甚至有所下降。校正后的数值与文献中地面测量的结果较相近,说明在使用半球照相法测量川西亚高山针叶林LAI 时必须加以校正。 8. 在3 个样地中,白桦、岷江冷杉和方枝柏种群为丛聚分布,紫果云杉在FF和SF 样地中基本上为随机分布。3 个物种出现丛聚分布的最短距离约为2m,在最短距离以内则为随机分布。最短距离可能与树冠大小有关,种子传播特征以及对光照的需求状况可能是造成这种分布格局类型的原因。 Radiative transfer plays a key role in forest ecosystems. Solar radiation providesenergy for photosynthesis, appropriate ambient temperature and development informationfor plants. However, quality and quantity of radiation reaching land surface are affected byweather and subsequently influence the growth and development of plants, which in turnchanges the budget of radiation in forest. Soil temperature changes with the variation ofradiation under forest canopy and influences the activity of roots and rate of nutrientturnover. Thus, any changes of radiation will induce chain reactions in the entireecosystem and display in the value of net primary productivity which will possibly shiftthe relationship between carbon source and sink at local or regional scale and feed back tothe global climate system. On the other hand, as a component of ecosystems, humanbeings of course need to demand more materials and better service from ecosystems. Forthese purpose, man must adapt their pattern and frequency of interference to ecosystems.This paper aims to research on the canopy structure, the radiation distribution and theirinfluence on soil temperature from the process of radiative transfer in subalpine forestecosystem of western Sichuan. The main results are: 1 Present a new photogrammetric method for leaf area. The main idea is to convertnon-vertically taken images of planar leaves to orthoimages through projectivetransformation. The resultant images are used to get leaf morphological parametersthrough image processing. This method enables users to take photos at almost anyorientation and distance if only the leaves are placed on same plane, and to processlarge quantity of leaves in a short time, which is suitable for field measurement. Theresolution of leaf area is adjustable to fit for special requirement. 2 A model using hemispherical photos combining with solar tracks and radiation courseis provided to simulate light variation in forest. The hemispherical photos of canopyrecord the real spatial distribution of each element of plants viewed from a point. Skyradiance is simulated with CIE standard clear sky or cloudy sky model. This modelcan be used to simulate real time light variation under canopy. 3 Present a soil temperature model. Soil could be regarded as a body of resistor andcapacitor. Some of the budget of solar radiation in soil body is transformed into soilpotential energy, the soil temperature. Variation of soil temperature is driven by solarradiation, vegetation, soil properties, etc. This model has two parameters, one of whichis time constant and is related to soil water content. The inversed model can be used tosimulate the variation of soil water. 4 By using model tRAYci developed by Brunner (1998), the 3-D distribution of light inthree subalpine forest stands of Wanglang Nature Reserve has been simulated andvalidated with value of radiometers in these stands. This model can basically satisfythe need for understanding light regimes of these stands. 5 Present some principles and questions of NPP (net primary of productivity) researchesin western Sichuan. The standard leaf area index (LAI) defined by Chen and Black(1997) has not been used in this region. Total leaf area and projected leaf area indexare still used in NPP researches which may differ around 1-fold in magnitude. Thestandard LAI which is a half of total leaf area above unit land area should be between4 and 5 for typical subalpine coniferous forest of western Sichuan concluded fromliteratures. The maximum forest NPP occurs in West China rain belt and decreasesnorthwestwards. Average NPP of spruce-fir forest in western Sichuan is about600gDM m-2 a-1, which is below the potential NPP of 1800gDM m-2 a-1 based onmeasured radiation in this region. The significant difference between potential and realNPP suggests that other factors influence the growth of stands. 6 In the three subalpine forest stands of Wanglang Nature Reserve, herbage layer ofAbstractbirch stand (BF) with age of 40 is dominated by heliophytes of Deyeuxia scabrescens,Origanum vulgare, Aster tongoloa etc.. However, both of the other two stands aredominated by shade tolerent species, such as Impatiens noli-tangere, Impatiensdicentra, Cacalia deltophylla and Pternopetalum tanakae etc. in fir stand (FF) withage of 180 and Fragaria orientalis, Cardamine tangutorum and Oxalis corniculata etc.in spruce stand (SF) with age of 330. Shrub species in the latter two stands arerelatively rich, typical dominant genera being Euonymus, Acanthopanax, Ribes andLonicera. Birch stand has relatively sparse shrubs dominated by genera of Cotoneaster,Corylus and Carpinus. Mosses are significant only in spruce stand. The canopystructure controls the light regime of stand, which influence the composition of herblayers beneath the canopy. This light regime-community structure relationship can beused to infer the herb community from canopy structure. The NPP derived from timbervolume of arbor layer of the three stands decreases from BF to SF, which is in thesame order of transmitted total radiation under canopy and age of these stands,suggesting the driving effect of radiation in the succession of community. 7 The highest effective LAI of the three stands obtained by hemispherical photos is inplot SF and lowest in plot BF. After rectification of the clumping effect of leaves onshoot, the real LAI in plot SF increases significantly (89%) and approximate to theaverage LAI of coniferous forest in western Sichuan. Therefore, the LAI obtainedfrom hemispherical photos needs rectification for clumping effect. 8 Spatial distribution pattern for Betula platyphylla, Abies faxoniana and Sabinasaltuaria is clumpy, but Picea purpurea almost random in plot FF and SF. The shortestdistance for clumpy distribution for Betula platyphylla and Sabina saltuaria is 1.5m,and 2m for Abies faxoniana. And random pattern for these trees is exhibited within thisrange which almost coincides with the diameter of crown. Seed dispersalcharacteristics and light requirement may be the reason for different spatial pattern.
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臭氧层损耗导致的地球表面UV-B辐射增强以及温室气体增多引起的气候变暖是当今两大全球环境问题。UV-B辐射增强和气候变暖对陆地植物和生态系统产生深远影响,并已成为全球变化研究的重要议题。作为世界第三极的青藏高原,UV-B 辐射增强以及气候变暖现象尤为突出。本试验所在林区是青藏高原东缘的主要林区,具有大面积的亚高山人工针叶成熟林,在全球变化背景下该森林的天然更新潜力如何是急待回答的重要问题。基于此,本研究围绕森林树种的种子和幼苗这一更新的重要阶段,开展了气候变暖、UV-B辐射增强和联合胁迫对云杉种子萌发及幼苗定居影响的研究,旨在全球变化背景下,探讨全球变暖、UV-B 辐射增强和联合胁迫是否对西南地区大面积人工亚高山针叶林更新的种子萌发和幼苗定居阶段产生影响。 本文以青藏高原东缘亚高山针叶林主要树种云杉为研究对象,研究云杉种子萌发及幼苗的生长和生理对UV-B辐射增强与气候变暖的响应。采用UV-B荧光灯(UV-lamp)来模拟增强的UV-B 辐射,此外,采用开顶式有机玻璃罩(OTCs)来模拟气候变暖。本试验包括四个处理:(1)大气UV-B 辐射+大气温度(C);(2)大气UV-B 辐射+模拟气候变暖(W);(3)增强的UV-B辐射+大气温度(U);(4)增强的UV-B辐射+模拟气候变暖(U+W)。 根据本试验结果,UV-B辐射增强对云杉种子萌发没有显著影响,它对萌发云杉幼苗的影响主要体现在幼叶展开以后。根据两年的试验结果,增强的UV-B辐射降低了云杉幼苗抗氧化酶活性,降低了抗氧化物质的含量,此外,造成了膜质的过氧化,表现为MDA在针叶中的积累。增强的UV-B照射处理萌发云杉幼苗两年后,幼苗的生长受到显著抑制。我们的结果显示,OTCs分别提高了空气(10 cm)和土壤(5 cm)温度1.74℃和0.94 ℃。增温显著地促进了云杉种子提前萌发,提高了萌发速率和萌发比率,而且,明显地促进了幼苗的生长,表现为株高和生物量累积的显著增长。此外增温还有利于云杉幼苗根的伸长生长以及生物量的累积,这可以使云杉幼苗更好地利用土壤中的水分和营养元素。 根据本试验结果,温度升高显著地促进了增强UV-B辐射下云杉萌发幼苗的生长,这说明,温度升高缓解了UV-B辐射增强对云杉萌发幼苗的负面影响。这种缓解作用可能是温度升高对UV-B辐射增强处理下幼苗的抗氧化系统活性改善的结果。温度升高还缓解了高UV-B辐射对云杉幼苗根生长的抑制作用,这也可能是增温缓解伤害的原因之一。此外,根据我们的试验结果,增温与UV-B辐射增强联合作用(U+W)下云杉萌发幼苗的生长状况好于大气温度与大气UV-B辐射联合(C)处理,表现为株高、地径、根长和生物量积累均高于C处理,因此可以推断,UV-B辐射增强与气候变暖同时存在对萌发幼苗在两年之内的生长没有产生抑制作用,也就是说,气候变暖的缓解作用完全弥补了UV-B辐射增强的有害作用。 同样,增强的UV-B辐射显著影响了云杉幼苗的光合作用,表现为净光合速率(Pn)和表观量子效率(Φ)的提高,此外,根据我们的试验结果,它还造成了PSII的光抑制。增强的UV-B辐射显著抑制了云杉幼苗对营养元素的吸收,表现为大量营养元素、碳、钙、镁和锌含量的降低,但是,它却显著促进了铁在植株体内的积累。增温显著地提高了净光合速率,但是,它对光系统II(PSII)的光化学效率影响不大。温度升高缓解了UV-B增强对云杉幼苗光合作用的伤害,表现为净光合速率、表观量子效率以及PSII光化学效率的提高。此外,温度升高还缓解了UV-B辐射增强对离子吸收的抑制作用。 Enhanced UV-B radiation due to the reduction of O3 layer and global warming induced by increased greenhouse gases in the air have become the two pressing aspects of global climate changes. Moreover, enhanced UV-B radiation and warming have profound and long-term impacts on terrestrial plants and ecosystems, and the studies focusing on the two factors have attracted many attentions. Qinghai-Tibetan Plateau is the third in elevation in the world, and enhanced UV-B radiation and climate warming are especially prominent in this region. Our research located in the main forest belt in the eastern Qinghai-Tibetan Plateau where large areas of subalpine coniferous forests distributed. Based on that, we carried out a research to study the effects of enhanced UV-B radiation and climate warming on seed germination and seedlings growth of seedlings which are the important basic stage in forest regeneration. This research was arranged by a complete factorial design and included two factors (UV-B radiation and temperature) with two levels. The UV-lamps were used to manipulate the supplemental UV-B radiation and open-top chambers (OTCs) were adopted to increase temperature. The four treatments were: (1) C, ambient UV-B without warming; (2) U, enhanced UV-B without warming; (3) W, ambient UV-B with OTCs warming; (4) U+W, enhanced UV-B with OTCs warming. The main results were exhibited as follows: 1. Based on our results in this research, OTCs increased temperature on average 1.74℃ in air (10 cm above ground) and 0.92 ℃ in soil (5 cm beneath ground). Furthermore, OTCs also slightly reduced soil moisture and relative air humidity, however, the differences was not statistically significant. 2. Our results showed that enhanced UV-B had no significant effects on the seeds germination of P. asperata. Enhanced UV-B affected sprouts of P. asperata until the needles unfolded. During two years, enhanced UV-B inhibited the efficiency of the antioxidant defense systems, and as a result, it induced oxidant stress and the accumulation of MDA in needles. After two years of exposure to enhanced UV-B, the growth of P. asperata sprouts was markedly restrained compared with those under ambient UV-B radiation and temperature (C). Warming significantly stimulated the germination speed and increased the germination rate of P. asperata seeds. In the next place, it prominently facilitated the growth of P. asperata sprouts, represented as improvements in stem elongation and biomass accumulation. Furthermore, warming also increased root growth of P. asperata sprouts, which could made sprouts more efficient to use water and nutrient elements in soil. In this research, warming alleviated the deleterious effects of enhanced UV-B on P. asperata sprouts. It markedly stimulated the growth of P. asperata sprouts exposed to enhanced UV-B. The ease effects of warming on the abilities of the antioxidant defense systems might account for its amending effects on growth. After two years of exposure to enhanced UV-B radiation and warming, the growth of P. asperata sprouts was better than those under ambient UV-B radiation without warming (C), which could be seen from the higher plant height, basal diameter, root length and total biomass accumulation compared with C. 3. Enhanced UV-B radiation significantly influenced the photosynthesis processes of two-year old P. asperata seedlings. Our results showed that enhanced UV-B reduced the net photosynthetic rate (Pn) and the apparent quantum efficiency (Φ), and induced photoinhibition of photosynthetic system II (PSII). Enhanced UV-B significantly decreased the concentration of nitrogen (N), phosphorous (P), potassium (K), calcium (Ca), magnesium (Mg) and zinc (Zn), however, it increased the accumulation of iron (Fe) in the whole plant of P. asperata seedlings. Warming significantly stimulated Pn of P. asperata seedlings but it had no prominent impacts on the photochemical efficiency of PSII. In our research, warming also alleviated the harmful effects of enhanced UV-B on photosynthesis and absorption of ions of P. asperata seedlings. It increased Pn, Φ and the photochemical efficiency of PSII in seedlings exposed to enhanced UV-B. Moreover, warming also increased the absorption of ions of the seedlings exposed to enhanced UV-B radiation.
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通过室内模拟和野外小区试验,采用中子活化分析手段,进行了运用REE 示踪条带施放法研究坡面土壤侵蚀垂直分布的可行性分析。结果表明:示踪元素条带施放法研究土壤侵蚀,可定量分析黄土坡面不同坡段的相对侵蚀量,具有满意的试验精度,并揭示了产沙强度随坡长存在3 种变化模式。
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作为黄土高原半农半牧区重要经济支柱的畜牧业 ,要确保其稳定增长 ,需在提高粮食单产、保障食物安全的前提下 ,保持及改善生态环境 ,通过畜牧业发展农村经济 ,增加农民收入 ,改变农村贫困落后状态。同时畜牧业可持续发展需要经济系统、社会系统、技术系统的共同支撑 ,优化协调畜牧业生产中的外部条件和环境 ,配套解决和优化畜牧业系统内部矛盾是畜牧业可持续发展的必经之路
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陕北黄土丘陵沟壑区 ,生态环境脆弱 ,水土流失严重 ,作为环境脆弱带的山坡生产型道路 ,对加剧土壤侵蚀起着重要的作用 ,属等外路。人们并不很重视的山坡生产型道路却与农村生产运输、经济交流密切相关 ,其建设与维护具有重要意义。通过对延安黄土丘陵沟壑区山坡生产型道路侵蚀状况调查及对道路防蚀建设的经验 ,总结了现有山坡道路侵蚀现状、方式、影响因素 ,并从生物、工程两方面初步阐述防蚀措施的配置与设计
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Thematic Mapper (TM) and Enhanced Thematic Mapper (ETM)+ data have been successfully employed in the field of mineral exploration to identify key minerals over arid and semi-arid terrains. However, redundant vegetation and cloud may seriously interfere with the discrimination of the minerals with diagnostic features. Therefore, in this study, we use masking technique to eliminate the negative influence of vegetation and cloud and Crosta technique to identify the diagnostic features of hydroxyl-minerals, carbonate-minerals and iron oxides. Then the anomalies were endowed with special colours and overlapped with the remote-sensing and geochemical data, overlaying images as remote-sensing anomalies. The mineral exploration work was carried through by synthetic analysis of the remote-sensing images, geochemical data and structures. Finally, areas with high correlation between the occurrence of hydrothermal alteration and presence of main faults and geochemical anomalies were considered as mineral exploration targets worthy of further detailed exploration programmes.
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Analysis of accommodation space variation during deposition of the Cretaceous Qingshankou Formation in the Songliao Basin, NE China, indicates that accommodation space changed both through time and across the basin as a seesaw movement. The mid-upper Qingshankou Formation is divided into three units. In each unit, changes of accommodation space differ in the southern and northern part of the basin. Increasing accommodation in the southern part is accompanied by a decrease in the northern part, and vice versa. Between the northern and southern basin, there was a neutral belt that is like a fulcrum, called the transformation belt here, where the accommodation did not change to any significant degree. We call this response 'accommodation transformation', whose characteristics are defined by tectonic subsidence analysis, palaeontological and sedimentary analyses. The accommodation increasing belt, decreasing belt, transformation belt and accommodation transformation boundary together constitute the accommodation transformation system. The recognition of accommodation transformation in the Songliao Basin provides a new insight into sequence stratigraphy and might be widely applicable.
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Quantitative studies on the evolution and dynamics of the deepwater area of Pearl River Mouth basin (PRMB) were carried out based on the latest geological and seismic data. The study area is generally in an extensional state during the Cenozoic. The major extension happened in the earlier syn-rift stages before 23 Ma and the extension after 23 Ma is negligible. Two rapid subsidence periods, 32-23 Ma and 5.3-2.6 Ma, are identified, which are related to the abrupt heat decay during margin breakup and the collision between the Philippine Sea plate and the Eurasian plate, respectively. The strongest crustal thinning in the Baiyun (sic) sag may trigger the syn-rift volcanism along the weak faulted belt around the sag. The Cenozoic tectonic evolution of the study area could be divided into five stages: rifting (similar to 50-40 Ma), rift-drift transition (similar to 40-32 Ma), early post-breakup (similar to 32-23 Ma), thermal subsidence (similar to 23-5.3 Ma) and neotectonic movement (similar to 5.3-0 Ma).
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The onshore-offshore deep seismic experiment was carried out for the first time and filled the blankness of the seismic surveys in the transition area between South China and northeastern South China Sea. The seismic data were analyzed and processed. The different seismic phases were identified and their travel time arrivals were modeled by ray-tracing to study the P-wave velocity crustal structure of this area. The crustal structure of this area is the continental crust. The crust thickness is gradually decreasing southward along the on-shore-offshore seismic line. The low-velocity layer (5.5 similar to 5.9 km (.) s(-1)) exists generally in the middle crust (about 10.0 similar to 18.0km)with about 2.5 similar to 4.0 km thickness, which is also thinning seaward. No obvious high-velocity layer appears in the lower crust. The Binhai (littoral) fault zone is a low velocity zone, which is located about 35km southeast to the Nan'ao station and corresponding to the gradient belt of gravity & magnetism anomalies. The depth of the fault zone is close to the Moho discontinuity. The littoral fault zone is a boundary between the normal continental crust of South China and the thinned continental crust of the sea area.
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近年来,东中国海赤潮灾情严重,且74.7%的赤潮集中在 30°30′~32°00′N、122°15′~123°10′E的“赤潮高发区”。在研究该区赤潮成因时,长江口沿岸上升流的影响越来越受到人们的关注,并被一些专家观测和研究。但目前为止,针对该区营养盐动力学特征及其对叶绿素a影响的研究较少,且不系统。 本文根据2004年四个季度月的调查资料,系统地探讨了长江口上升流区营养盐动力学特征;估算了上升流的营养盐通量,并和陆源输入通量进行了比较。初步探讨了上升流对该区营养盐结构和浮游植物生长的影响。为深入研究长江口富营养化和赤潮形成机制提供了参考。 结果表明春季在122°20′~123°00′E,31°00′~32°00′N以北海域存在低温、高盐、低溶解氧的沿岸上升流。它不但可把底层高含量磷酸盐输送到10m层以上海区,而且还为上层海区输入了相对低含量硝酸盐和硅酸盐,从而改善了上层营养盐结构,使得营养盐比值接近Redfield Ratios,同时还改善了上层的透明度;从而有利于浮游植物的繁殖。夏季上升流受到强大的长江冲淡水压制,表现不如春季明显,主体水团出现在122°20′~123°00′E,31°15′~31°50′N海区10m层以下。 在秋、冬季,上升流现象被更强的对流现象所掩盖,表现为台湾暖流表层水的入侵。表、底层水域不仅温、盐度分布十分接近,而且营养盐结构差异也较小。冬季台湾暖流水中的磷酸盐含量远比秋季高,与春、夏季上升流水团中磷酸盐含量接近。硝酸盐和硅酸盐含量比秋季稍高,比春、夏季上升流水团中的含量稍低。 叶绿素a季节性分布表明,在春、夏季的10m层以下水域,叶绿素a受到透明度限制,含量相差不大;而在表层和10m层之间,春季叶绿素a的含量远高于夏季,说明春季的营养盐结构和自然条件更有利于浮游植物的繁荣生长。在秋季台湾暖流水影响的区域,表层叶绿素a含量较夏季稍低。而冬季该区叶绿素a含量则是最低的。 对长江口上升流水团春季营养盐通量的计算结果表明,上升流水团中磷酸盐输送通量远远高于长江径流输入,是其径流通量的两倍以上,可能会成为影响该海区磷酸盐分布以及浮游植物生长的一个值得关注的因素。 关键词:上升流,营养盐动力学,营养盐结构,叶绿素a,长江冲淡水
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利用ERA40逐日再分析资料、NCEP/NCAR2逐日再分析资料、中国740个测站日降水资料、上海台风研究所提供的西太平洋热带气旋资料、Kaplan等重建的月平均SSTA资料、NOAA逐日长波辐射(OLR)等资料,应用离散功率谱分析、带通滤波、EOF分析等统计方法,研究了东亚夏季风(EASM)的移动特征、东亚地区季节内振荡(ISO)的基本特征、季节内振荡对东亚夏季风活动的影响、季节内振荡对东亚夏季风异常活动的影响机理。主要结论如下: (1)综合动力和热力因素定义了可动态描述东亚夏季风移动和强度的指数,并利用该指数研究了东亚夏季风的爆发和移动的季节内变化及其年际和年代际变化特征。研究发现,气候平均东亚夏季风前沿分别在28候、33候、36候、38候、40候、44候出现了明显的跳跃。东亚夏季风活动具有显著的年际变率,主要由于季风前沿在某些区域异常停滞和突然跨越北跳或南撤引起,造成中国东部旱涝灾害频繁发生。东亚夏季风的活动具有明显的年代际变化,在1965年、1980年、1994年发生了突变,造成中国东部降水由“南旱北涝”向“南涝北旱”的转变。 (2)东亚季风区季节内变化具有10~25d和30~60d两个波段的季节内振荡周期,以30-60d为主。存在三个主要低频模态,第一模态主要表征了EASM在长江中下游和华北地区活动期间的低频形势;第二模态印度洋-菲律宾由低频气旋式环流控制,主要表现了ISO在EASM爆发期间的低频形势;第三模态主要出现在EASM在华南和淮河活动期间的低频形势。第一模态和第三模态是代表东亚夏季风活动异常的主要低频形势。 (3)热带和副热带地区ISO总是沿垂直切变风的垂直方向传播。因此,在南海-菲律宾东北风垂直切变和副热带西太平洋北风垂直切变下,大气热源激发菲律宾附近交替出现的低频气旋和低频反气旋不断向西北传播,副热带西太平洋ISO以向西传播为主。中高纬度地区,乌拉尔山附近ISO以向东、向南移动或局地振荡为主;北太平洋中部ISO在某些情况下向南、向西传播。 (4)季风爆发期,伴随着热带东印度洋到菲律宾一系列低频气旋和低频反气旋, 冷空气向南输送,10~25天和30~60天季节内振荡低频气旋同时传入南海加快了南海夏季风的爆发。在气候态下,ISO活动表现的欧亚- 太平洋(EAP)以及太平洋-北美(PNA)低频波列分布特征(本文提出的EAP和PNA低频波列与传统意义上的二维定点相关得到的波列不同)。这种低频分布形式使得欧亚和太平洋中高纬度的槽、脊及太平洋副热带高压稳定、加强,东亚地区的低频波列则成为热带和中高纬度ISO相互作用影响东亚夏季风活动的纽带。不同的阶段表现不同的低频模态,30~60d低频模态的转变加快了EASM推进过程中跳跃性;30-60d低频模态的维持使得EASM前沿相对停滞。 (5)30-60d滤波场,菲律宾海域交替出现的低频气旋和低频反气旋不断向西北传播到南海-西太平洋一带。当南海-西太平洋地区低频气旋活跃时,季风槽加强、东伸,季风槽内热带气旋(TC)频数增加;当南海-西太平洋低频反气旋活跃时,季风槽减弱、西退,TC处于间歇期,生成位置不集中。 (6)在El Nino态下,大气季节内振荡偏弱,北传特征不明显,但ISO由中高纬度北太平洋中部向南和副热带西太平洋向西的传播特征显著,东亚地区ISO活动以第三模态为主,EASM集中停滞在华南和淮河流域,常伴随着持续性区域暴雨的出现,易造成华南和江淮流域洪涝灾害,长江和华北持续干旱。在La Nina态下,大气季节内振荡活跃,且具有明显的向北传播特征,PNA低频波列显著,东亚地区ISO活动以第一模态单峰为主;EASM主要停滞在长江中下游和华北地区,这些地区出现异常持续强降水,华南和淮河流域多干旱;在El Nino态向La Nina态转换期,ISO活动以第一模态双峰为主,长江中下游常常出现二度梅。
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为了提高铜板带成本管理的效率和准确性,提出了基于作业成本法的铜板带成本管理系统。文章首先分析了铜板带生产的工艺流程和组织结构,根据作业成本法的相关理论,建立了铜板带生产的作业中心,并进行资源分类、资源分配和成本核算。在此基础上构建了基于Web的,与ERP/MES集成的成本管理系统。该系统通过在某铜板带厂的实际应用,证明了其可行性和有效性。
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在带式输送机动态过程仿真的基础上 ,以多驱动带式输送机系统为对象 ,对可控多驱动系统进行动力学分析·采用基于功率跟踪的方法 ,在合理的启动曲线的基础上 ,将第一驱动按合理启动曲线启动 ,其他驱动顺次跟踪第一驱动功率的控制策略·基于有限元方法建立了系统的动力学方程 ,提出了可控启动过程的动态分析算法 ,开发了动态设计软件BCD 2 0 ,通过对实际系统的仿真 ,证明了算法和软件的正确性·
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研究了带式输送机停机过程的动态设计 ,通过分析提出了输送机停机过程的力学模型为两种 :第 1模型与启动过程的力学模型相同 ,第 2模型为具有固定端的振动模型·分析了制动力的传动机理 ;在综合各种停机方式的基础上给出了停机过程的分类 ,提出了控制速度停机、自由停机和制动停机的计算方式及其计算方法 ;开发了带式输送机动态分析软件BCD .2 0的停机计算部分 ;应用软件对停机过程进行仿真研究 ,对停机过程进行了分析 ;给出了停机过程的动态设计方法和拉紧装置行程的计算式 ;得出了不同的停机方式结束后输送带的张力分布是不同的结果·所提出的方法可用于大型带式输送机停机过程的合理设计 ,避免事故的发生
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The lithology of the buried hill of Triassic Budate group in Beier depression is epimetamorphic clastic rock and volcanic clastic rock stratum. Recently the favorable hydrocarbon show was discovered in buried hill of base rock, and large-duty industrial oil stream was obtained in some wells in Beier depression. Based on the information of seismos and wells, the tectonic framework, tectonic deformation times and faulted system of the Beier depression are comprehensively studied, then configuration, evolutional history, genetic type and distributed regularity of buried hill are defined. According to observing description and analysis of core sample, well logging and interpretive result of FMI, the lithological component, diagenetic type and diagenetic sequence of buried hill reservoir are confirmed, then reservoir space system of buried hill is distinguished, and vegetal feature, genetic mechanism and distributed regularity of buried hill fissure are researched, at the same time the quantitative relationship is build up between core fissures and fissures interpreted by FMI. After that fundamental supervisory action of fault is defined to the vegetal degree of fissure, and the fissure beneficial places are forecasted using fractal theory and approach. At last the beneficial areas of Budate group reservoir are forecasted by reservoir appraisal parameters optimization such as multivariate gradually regression analysis et. al. and reservoir comprehensive appraisal method such as weighing analyze and clustering procedure et. al. which can provide foundation for the next exploratory disposition. Such production and knowledge are obtained in this text as those: 1. Four structural layers and two faulting systems are developed, and four structural layers are carved up by three bed succession boundary surfaces which creates three tectonic distortional times homology. Three types of buried hill are divided, they are ancient physiognomy buried hill, epigenetic buried hill, and contemporaneous buried hill. 2. Reservoir space of Budate buried hill is mainly secondary pore space and fissure, which distributes near the unconformity and/or inside buried hill in sections. The buried hill reservoir experienced multi-type and multi-stage diagenetic reconstruction, which led to the original porosity disappeared, and multi secondary porosity was created by dissolution, superficial clastation and cataclasis et. al. in diagenetic stage, which including middle crystal pore, inter crystal pore, moldic pore, inter particle emposieu, corrosion pore space and fissure et. al. which improved distinctly reservoir capability of buried hill. 3. The inner reservoir of buried hill in Beier depression is not stratigraphic bedded construction, but is fissure developing place formed by inner fault and broken lithogenetic belt. The fissures in inner reservoir of buried hill are developed unequally with many fissure types, which mainly are high angle fissure and dictyonal fissures and its developing degree and distribution is chiefly controlled by faulting. 4. The results of reservoir comprehensive evaluate and reservoir predicting indicates that advantageous areas of reservoir of buried hill chiefly distributes in Sudeerte, Beixi and Huoduomoer, which comprehensive evaluate mainly Ⅱand Ⅲ type reservoir. The clues and results of this text have directive significance for understanding the hydrocarbon reservoir condition of buried hill in Beier depression, for studying hydrocarbon accumulated mechanism and distributed regularity, and for guiding oil and gas exploration. The results of this text also can enrich and improve nonmarine hydrocarbon accumulated theory.