32 resultados para Tourist gathering


Relevância:

10.00% 10.00%

Publicador:

Resumo:

National Natural Science Foundation of China; Public Administration and Civil Service Bureau of Macau SAR; Companhia de Telecomunicacoes de Macau S.A.R.L.; Macau SAR Government Tourist Office

Relevância:

10.00% 10.00%

Publicador:

Resumo:

National Natural Science Foundation of China; Public Administration and Civil Service Bureau of Macau SAR; Companhia de Telecomunicacoes de Macau S.A.R.L.; Macau SAR Government Tourist Office

Relevância:

10.00% 10.00%

Publicador:

Resumo:

National Natural Science Foundation of China; Public Administration and Civil Service Bureau of Macau SAR; Companhia de Telecomunicacoes de Macau S.A.R.L.; Macau SAR Government Tourist Office

Relevância:

10.00% 10.00%

Publicador:

Resumo:

提出了一个用于描述异步π-演算中移动进程的时态和空间性质的模态逻辑.该逻辑具有基于谓词变量的递归构造.建立了这一逻辑的语义理论,并证明了语义的单调性,从而保证了不动点的存在.还设计了一个算法来自动地检测移动进程是否具有用该逻辑公式所描述的性质,并证明了该算法的正确性.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

National Natural Science Foundation of China; Public Administration and Civil Service Bureau of Macau SAR; Companhia de Telecomunicacoes de Macau S.A.R.L.; Macau SAR Government Tourist Office

Relevância:

10.00% 10.00%

Publicador:

Resumo:

National Natural Science Foundation of China; Public Administration and Civil Service Bureau of Macau SAR; Companhia de Telecomunicacoes de Macau S.A.R.L.; Macau SAR Government Tourist Office

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The steplike density of states obtained from reflectance-difference spectroscopy demonstrates that ultrathin InAs layers should be regarded as two-dimensional quantum wells rather than isolated clusters, even for the sample with only 1/3 monolayer InAs in (311)-oriented GaAs. The degree of anisotropy is within the intrinsic anisotropy of (311)-oriented ultrathin quantum wells, indicating that there is little structural or strain anisotropy in the InAs islands. (C) 1998 Elsevier Science B.V.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

日益增强的旅游活动干扰正成为九寨沟世界自然遗产的有效保护与持续管理不可回避的挑战,已成为当前区域生态保护与经济发展的焦点问题之一。阐明相关旅游的干扰活动对核心景区植物物种组成、多样性与结构的影响是九寨沟有效保护与持续管理的必要前提和基础,然而至今少有研究。选择九寨沟与旅游活动相关的九个景点、公路建设地段以及退耕地还林地,详细调查了林下植被结构、物种组成与多样性,比较了相关旅游活动干扰与基本未受干扰地段的差异。目的是阐明九寨沟核心景区旅游干扰条件下植物多样性与群落结构及其特点,揭示旅游干扰与植被结构和生物多样的相互关系,评估九寨沟旅游管理的有效性,探索减免旅游干扰影响的对策与措施。初步结论如下。 1.旅游活动引起九寨沟核心景区植物组成和群落结构特征改变显著。栈道及公路附近许多耐荫喜湿的敏感种局部消失,而早熟禾、车前草、委陵菜等耐干旱、耐践踏、繁殖能力强的植物种群扩大;外来物种频繁出现并已少量侵入干扰相对较轻的林分深处;林下群落以草本植物为优势,灌木与苔藓植物的频度、盖度、高度以及灌木密度均有所下降。可见,大量的游人活动和景区公路建设已对九寨沟丰富的乡土植物构成极大威胁,导致其生物多样性降低。而九寨沟农耕地退耕有利于九寨沟生态环境和生物多样性保护,正逐步向稳定群落演替。 2.干扰强度的差异导致九寨沟植物所受影响的程度不同。栈道附近植物受影响的程度与游人活动频率有关,活动频率高的地段干扰强度大,对植物的影响程度重,反之植物所受的影响较轻。强度干扰地段,耐荫喜湿的物种少见,伴生植物优势地位突出,生物多样性明显降低,植物群落结构特征改变也极为显著;干扰较轻的地段,伴生物种少量出现,植物群落结构变化不明显,生物多样性略为降低,部分地区结构参数值和多样性指数有所升高。公路修建是一种强度干扰,它导致附近植物种类极为单一,草本优势种异常突出,多数植物生活力低下、生长更新能力差。 3.不同植物类群受干扰影响的程度不同。草本及苔藓植物的种类组成和多样性指数受干扰影响较大,灌木和苔藓植物的结构受干扰影响较大,苔藓植物对干扰影响最为敏感。 综合分析表明,九寨沟核心景区的管理虽然比较规范,但目前核心区热点景点段的管理仍然不够,旅游活动驱动了林下植被退化明显、物种组成显著变化、生物多样性衰退、非乡土喜光耐旱种群扩大。导致九寨沟核心区旅游活动与生物多样性保护目标尖锐冲突,进一步约束旅游活动带来的干扰,强化管理,开展林下植被恢复与非乡土喜光耐旱种群调控是九寨沟自然遗产地保护一项紧迫任务。 The increasing tourism disturbance is an unavoidable challenge to effective conservation and sustained tourist management of Jiuzhaigou Nature Reserve. It has become one of the focal problems of regional ecological protect and economic development. It is important to clarify effects of tourism disturbance on plant species composition, diversity and community structure in kernel spot for effective conservation and sustained tourist management in Jiuzhaigou, China. However, there were little studies about this yet. The study investigated the vegetation structure, species composition and diversity at nine sight spot, road area and four abandoned farmlands connecting with tourism, and compared the differences between disturbed area and undisturbed area. The purpose of the this study is clarifying the plant diversity and community structure and characteristics of the disturbed area in kernel spot of Jiuzhaigou, discovering the relation between vegetation structure and biodiversity, evaluating the effect of tourist management and exploring the measure decreasing tourist disturbance. Our results are following: 1. Tourism disturbance caused a significant change in species composition and structure of plant communities in kernel Spot of Jiuzhaigou. In the vicinity of plank and road, some native shade-tolerant or hygrophilous plants had disappeared, accompanying with the population expansion of some xerophilous and disturbance-resisting species such as Poa sp. Plantago depressa, Potentiila multicaulis and some exotic and synanthropic species. Herbs were domaint species, while frequency coverage and height of shrubs and bryophytes, and shrub density decreased. In indicated that tourist activities and build of road had adversely affected on native plant species, and led to decline in biodiversity of Jiuzhaigou Nature Reserve. Abandoned farmlands maybe conduced to entironment and biodiversity conservation. 2. Nearby the plank, influency variable of tourism disturbance on plant was alosely and positively correlated with disturbance intensity. There was companion plant species and lacked shape-loving species in heavy disturbed areas, which caused decrease in biodiversity and significant change in community structure in these places. On the contrary, in the slightly disturbed areas, some companion speices displayed and biodiversity decreased slightly, but no significant change in community structure in these areas. The biuld of road is a heavy disturbance form, which led to increase of herb species and to decrease in vitality and regeneration capacity. 3. The intensity of tourism disturbance on plant depended on plant groups. Tourism interference significantly influenced species composition and diversity index of herb and bryophyte; it also significantly influenced community structure; the bryophyte was more sensitive to tourism disturbance. Our result indicated that the management in kernel spot of Jiuzhaigou is relatively reasonable, but not adequate. Tourism speed the degradation of the vegetation under woodland, the change of the species composition, the decreaing of the biodiversity and the expanding of the exotic sunloving plant populations. The contradiction between tourism and conserving biodiversity is increasing, so enforcing management, regenerating the vegetation under woodland and adjusting the exotic sunloving arid-tolerent plant populations is a pressing work to protect the Jiuzhaigou natural legacy.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

日益增强的旅游活动干扰已成为九寨沟世界自然遗产的有效保护与持续管理不可回避的问题,也已成为当前区域生态保护与经济发展的焦点问题之一。评估乡土植物种的基本特征、质量、种子休眠程度以及萌发能力;筛选适宜的植被恢复乡土物种并选择有效植被恢复技术措施是开展植被恢复试验的重要前提和保障。本文以九寨沟世界自然遗产为例,通过对景区乡土植物种子基本特征的测定以及采用乡土物种作为植被恢复技术试验与恢复技术筛选的试验物种,在景区旅游干扰区的三种生境类型:原始针叶林、混交林和边坡,根据不同的影响因素设计试验,从而探索适宜的恢复措施和植被恢复物种。初步结论如下: 1. 本文研究的28种乡土植物中,17种测定的物种活力较高(>72%),均具有作为恢复物种的潜力。但28种种子中75%的发芽率为0%。大部分种子存在一定程度的休眠,包括甘肃山楂、称花藤、疏花槭、陇东海棠、球花荚迷、巴东小檗、蔷薇、宝兴栒子、光泽栒子、光枝柳叶忍冬、甘青铁线莲、毛果铁线莲、宽叶旌节花、糙叶五加和独活。因而种子存在深度休眠是乡土物种自然更新和植被恢复的主要障碍,需要根据种子的形态生理特征,寻求打破乡土植物种子休眠的有效方法,提高种子发芽率。 2.低温层积只显著提高了蔷薇、毛果铁线莲、宽叶旌节花和假升麻3种种子的发芽率,也相对较早地提高了陇东海棠、鲜黄小檗和独活的萌发。对于其它物种的种子,低温层积没能有效打破休眠提高发芽率。综合分析结果表明九寨沟28种林下或林缘乡土植物中窄叶鲜卑花、毛果铁线莲、宽叶旌节花、假升麻、陇东海棠、鲜黄小檗和独活等12种可直播或通过低温层积处理后直播用于旅游干扰退化地段的植被恢复中,而其它的种类尚需进一步寻求打破休眠的措施以提高种子发芽能力。 3.在原始林生境下,七筋菇、巴东小檗、耳叶风毛菊、长叶毛花忍冬及独活5种乡土植物种子的出苗能力不高,因此目前急需提出有关提高种子出苗的方法措施。在相同的处理条件下,不同物种出苗数存在着较大的差异,相比而言,巴东小檗、耳叶风毛菊和长叶毛花忍冬种子出苗与幼苗存活较高,对于其环境适应能力较强,因此它们更适宜采用播种的方式应用于九寨沟原始林践踏地段地表的植被恢复实践;而七筋菇和独活在室内和自然气候条件下萌发都很困难,在植被恢复过程中,可考虑采用其它播种方式。而在边坡和混交林生境试验结果表明,供试物种无萌发和出苗现象,这可能跟外界环境条件、干扰和种子命运有关。 4. 本研究中腐殖质、松土和苔藓覆盖处理措施均未能提高物种出苗,且对样方内植被结构以及物种丰富度也无显著影响,其中的影响因素也是多方面的,因此还需进一步研究探索。但腐殖质对幼苗存活能力方面有一定的积极作用。 The increasing tourism disturbance is an unavoidable issue to effective conservation and sustaind tourist management of Jiuzhaigou Nature Reserve. It has become one of the focal problems of regional ecological protect and economic development. Assessing the traits, quality, seed dormancy and germination of native seed and choosing the suitable species and ways for vegetation restoration were the important precondition and guarantee before vegetation restoration. In this paper, as an example to Jiuzhaigou world nature heritage, through the estimation to the basic characteristics of native seeds and the use of native species for the test of vegetation restoration and the choosing of vegetation restoration techniques, in three different habitats being disturbed, including the primitive forest, mixed forest and side slope. According to different factors, designing experiments in order to explore the appropriate measures and species of vegetation restoration . Our results are as follows: 1. There are 77% seeds of the 28 species with high viability(>72%), which had the potential possibility of being restoration species. The germination of 75% of the seed was 0%.Most of the seed was dormant, So dormancy of seed was the barrier for natural regeneration and vegetation restoration, Further research is needed on investigating the other more effective methods to release seed dormancy of these native species in the future. 2. Cold stratification did not release seed dormancy of most species. In our study, there are only 3 species including Clematis peterae var. trichocarpa, Stachyurus chinensis and Aruncus sylvester (P<0.05) with germination percentage increased by cold stratification. By comprehensive analysis, the result shows: In 28 undergrowth native seeds, Sibiraea angustata, Clematis peterae var. trichocarpa, Stachyurus chinensis, Aruncus Sylvester, Malus kansuensis, Berberis diaphana,and Heracleum hemsleyanum could be used to vegetation restoration by sowing directly or sowing after cold stratification in degenerate gland being disturbed by turism, and othes seed of 28 were needed to search other methods to release seed dormancy for advancing the ability of germination. 3.In the habitat of primitive forest, the ability of emergence of the native species Clintonia udensis, Berberis henryana, Saussurea neofranchetii, Lonicera trichosantha var.xerocalyx and Heracleum hemsleyanum was low, so it is urgently needed to search about the methods of advancing emergence. In the sametreatment, the number of emergence of different species was very different. Relatively speaking, the emergence and seedling survival of the species Berberis henryana, Saussurea neofranchetii and Lonicera trichosantha var.xerocalyx was higher, and the adaptability of the species was better, so they were more suitable for vegetation restoration on trampling-induced degraded patches of primitive forest in Jiuzhaigou; But the germination of Clintonia udensis and Heracleum hemsleyanum was both difficult in laboratory and natural conditions, so it could be considered to apply other sowing methods. However, the result showed that: applied species didn’t germinate or emergent in the habitat of side slope and mixed forest, which could be related to external environment conditions, interference and the fate of the seed. 4.In this study, humus, scatification and bryophyte cover measures didn’t advance the emergence of the species or the structure of vegetation and richness in plot significantly, the impact factors of which were many, therefore further research is needed . However, humus had a certain positive effect on the ability of seedling survival.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

随着原子核科学技术的发展,无论是对原子核内部特征和规律的研究,或者是对原子核科学技术的应用,都需要对核辐射和原子核所携带的信息进行测量和分析研究。在核电子学测量系统中,核辐射探测器输出信号在经过各种信号处理电路后,通常都要变换成数字信号,再经过数据收集和处理,给出实验的最终结果,因此实验工作的任何进展都要求有相应的数据获取和处理系统的支持。根据实验的实际需求,我们以采集、处理探测器输出的信号为题,开展了一些研究工作,我们先后开展的研究工作包括以下儿个方面:1.激光功率计的变换与显示电路的研制2.基于PCI总线、嵌入8051单片机的计数卡的研制3.数据处理分析软件的设计这三部分的设计工作我们将在论文的第二、第三、第四章分别进行阐述。激光功率计的变换与显示电路把由激光功率计输出的模拟电压量变为数字脉冲输出,并且把该输出脉冲的频率实时定性显示出来。本电路测量精度高,线性好,工作稳定。我们研制开发的计数卡是一种很实用的计数卡,它是一种基于PCI总线,嵌入单片机的高速计数器,最大计数范围为109-1,最高的计数频率为20MHz。该计数卡计数范围宽,计数频率高,具有定时计数、重复计数等功能,可以取代常规的定标器,具有广泛的应用前景。数据处理分析软件包括下位机软件、上位机软件及通讯协议三部分,实现数据的采集与记录,并将读取的数据以Excel电子表格的形式存储,以备查询。下位机的软件采用KeilC编写,上位机软件采用Delphi编写。目前激光功率计的变换与显示电路和计数卡及相应的数据处理软件都设计、调试完成,已经投入使用,获得满意结果,受到好评。

Relevância:

10.00% 10.00%

Publicador:

Resumo:

土地资源动态监测信息系统是在计算机软硬件支持下 ,对土地资源采集、输入、编辑、存储和综合分析应用的技术系统 ,它是土地资源动态监测、土地评价、土地利用规划和管理的有力工具。本文以延安 /安塞七乡镇为例 ,启用 ARC/INFO和 Arcview软件 ,建立土地资源动态监测系统 ,并对监测结果初步分析 ,为区域土地资源管理和合理利用提供服务

Relevância:

10.00% 10.00%

Publicador:

Resumo:

机会移动传感器网络可应用在野生动物监控,或利用手持设备嵌入的传感器收集城市信息等场景,往往需要将数据从源节点传输到多个基站中的任一个.提出了一个基于虚拟空间的路由机制VSR(virtual space-based routing),采用"存储-携带-转发"的传输模式实现数据收集.每个传感器节点根据与多个sink节点的期望传输延迟映射成高维空间中的一个坐标点,消息传输对应于从源节点移动到空间原点的过程.细粒度的转发决策特性,使VSR自适应于网络的动态变化,具有很好的鲁棒性.此外,VSR机制具有很低的计算和存储开销,非常适合资源受限的传感器节点.两种不同随机特性场景下的模拟实验验证了VSR机制比ZebraNet的基于历史的转发机制和随机转发机制的性能更好.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

对古龙咀周围浅海区沉积物的粒度进行了测试与分析,结合相关的地质水文资料,探讨了海岸形态对沉积物粒度的影响。研究区表层沉积物平均粒径在海湾浅海区呈带状由岸向海变细,中等水深和岬角处分布着细粒区,向外海粒径相对变粗;除险岛湾砂质区外,分选差;偏态多数为正偏或近正态;整体峰形极窄,峰型多样。底质类型以粘土质粉砂和砂质粉砂为主,由东北经古龙咀岬角向西南形成S形粘土质粉砂分布带,险岛湾地区沉积物呈带状由砂逐渐过渡到粉砂。潮汐和波浪是本区沉积物输运的主要水动力,岬角的存在影响了沉积物粒度的分布。粒度趋势分析表明沉积物整体有向岬角汇聚的输运趋势。 对收集到基于1954年、1969年、1982年测量绘成的地形图水深数据进行数字化,结合2005年测量的水深数据,分别建立各时期DEM图,在此基础上分析研究区的地形特征。四个时期海底DEM呈现出大体一致的趋势,在险岛湾及白沙口海湾内为浅水区,水深值在-1~-4 m之间,深水区主要分布在南黄岛南端至古龙咀连线以南区域,呈扇形展布,水深由南黄岛两侧向中间逐渐加深,水深值在-10~ -17 m之间。从整体上看,研究区海底地形呈NW-SE方向逐渐加深。 将数字化后的水深数据统一校正到1956黄海高程系,分别建立DEM,运用GIS的栅格计算分析得出冲淤变化图。相关结果表明:1954~1969年研究区整体近岸为冲(险岛湾除外),离岸海域为淤;1969~1982年研究区总体处于弱淤积状态;1982-2005研究区海域近岸为淤,外海以弱冲刷状态为主。

Relevância:

10.00% 10.00%

Publicador:

Resumo:

What geophysical inversion studied includes the common mathematics physical property of inversion and the constitution and appraisal method of solution in geophysics domain, i.e. using observed physical phenomenon from the earth surface to infer space changing and physical property structure of medium within the earth. Seismic inversion is a branch of geophysical inversion. The basic purpose of seismic inversion is to utilizing seismic wave propagating law in the medium underground to infer stratum structure and space distribution of physical property according to data acquisition, processing and interpretation, and then offer the vital foundation for exploratory development. Poststack inversion is convenient and swift, its acoustic impedance inversion product can reflect reservoir interior changing rule to a certain degree, but poststack data lack abundant amplitude and travel time information included in prestack data because of multiple superimpose and weaken the sensitiveness which reflecting reservoir property. Compared with poststack seismic inversion, prestack seismic inversion has better fidelity and more adequate information. Prestack seismic inversion, including waveform inversion, not only suitable for thin strata physical property inversion, it can also inverse reservoir oil-bearing ability. Prestack seismic inversion and prestack elastic impedance inversion maintain avo information, sufficiently applying seismic gathering data with different incident angle, partial angle stack, gradient and intercept seismic data cube. Prestack inversion and poststack inversion technology were studied in this dissertation. A joint inversion method which synthesize prestack elastic wave waveform inversion, prestack elastic impedance inversion and poststack inversion was proposed by making fully use of prestack inversion multiple information and relatively fast and steady characteristic of poststack inversion. Using the proposed method to extract rock physics attribute cube with clear physical significance and reflecting reservoir characterization, such as P-wave and S-wave impedance, P-wave and S-wave velocity, velocity ratio, density, Poisson ratio and Lame’s constant. Regarding loose sand reservoir in lower member of Minghuazhen formation, 32-6 south districts in Qinhuangdao,as the research object, be aimed at the different between shallow layer loose sand and deep layer tight sand, first of all, acquire physical property parameters suitable for this kind of heavy oil pool according to experimental study, establishing initial pressure and shear wave relational model; Afterwards, performing prestack elastic wave forward and inversion research, summarizing rules under the guidance of theoretical research and numerical simulation, performing elastic impedance inversion, calculating rock physics attributes; Finally, predicting sand body distribution according to rock physics parameters, and predicting favorable oil area combine well-logging materials and made good results.