The mycobiota of discoloured needles of the Swiss stone pine (<Emphasis Type="Italic">Pinus cembra</Emphasis> L.) in the Tatra Mountains (Poland)     

Wojciech Pusz  Anna Baturo-Cieśniewska  Tomasz Zwijacz-Kozica 《山地科学学报》2018,15(12):2614-2621

The Swiss stone Pine (Pinus cembra L.) is an alpine species, fairly commonly occurring in the Alps and the Carpathians, close to the timberline. Natural sites of the Swiss stone pine in Poland are found exclusively in the Tatra Mountains, within the area of the Tatra National Park (TNP). In 2017, the health status of the needles of P. cembra was determined and their mycological analysis was carried out. As a result, 11 species of fungi were isolated from the needles showing disease symptoms, manifested by various shades of discoloration. The most frequently observed species was Fusarium oxysporum. It probably does not bring on disease symptoms, but may affect the development of other frequently isolated species (such as Sydowia polyspora, Lophodermium sp. and Lophodermium conigenum) that are pathogenic to Pinus spp.  相似文献   

Review of pre-processing technologies for ice cores     

Wen-tao Du  Shi-chang Kang  Xiang Qin  Wei-jun Sun  Yu-lan Zhang  Yu-shuo Liu  Ji-zu Chen 《山地科学学报》2018,15(9):1950-1960

High-resolution ice core records covering long time spans enable reconstruction of the past climatic and environmental conditions allowing the investigation of the earth system’s evolution. Preprocessing of ice cores has direct impacts on the data quality control for further analysis since the conventional ice core processing is time-consuming, produces qualitative data, leads to ice mass loss, and leads to risks of potential secondary pollution. However, over the past several decades, preprocessing of ice cores has received less attention than the improvement of ice drilling, the analytical methodology of various indices, and the researches on the climatic and environmental significance of ice core records. Therefore, this papers reviews the development of the processing for ice cores including framework, design as well as materials, analyzes the technical advantages and disadvantages of the different systems. In the past, continuous flow analysis (CFA) has been successfully applied to process the polar ice cores. However, it is not suitable for ice cores outside polar region because of high level of particles, the memory effect between samples, and the filtration before injection. Ice core processing is a subtle and professional operation due to the fragility of the nonmetallic materials and the random distribution of particles and air bubbles in ice cores, which aggravates uncertainty in the measurements. The future developments of CFA are discussed in preprocessing, memory effect, challenge for brittle ice, coupling with real-time analysis and optimization of CFA in the field. Furthermore, non-polluting cutters with many different configurations could be designed to cut and scrape in multiple directions and to separate inner and outer portions of the core. This system also needs to be coupled with streamlined operation of packaging, coding, and stacking that can be implemented at high resolution and rate, avoiding manual intervention. At the same time, information of the longitudinal sections could be scanned and identified, and then classified to obtain quantitative data. In addition, irregular ice volume and weight can also be obtained accurately. These improvements are recorded automatically via user-friendly interfaces. These innovations may be applied to other paleomedias with similar features and needs.  相似文献   

Numerical Simulation of the Vortex-Induced Vibration of A Curved Flexible Riser in Shear Flow     

Hong-jun Zhu  Peng-zhi Lin 《中国海洋工程》2018,32(3):301-311

A series of fully three-dimensional(3 D) numerical simulations of flow past a free-to-oscillate curved flexible riser in shear flow were conducted at Reynolds number of 185–1015. The numerical results obtained by the two-way fluid–structure interaction(FSI) simulations are in good agreement with the experimental results reported in the earlier study. It is further found that the frequency transition is out of phase not only in the inline(IL) and crossflow(CF) directions but also along the span direction. The mode competition leads to the non-zero nodes of the rootmean-square(RMS) amplitude and the relatively chaotic trajectories. The fluid–structure interaction is to some extent reflected by the transverse velocity of the ambient fluid, which reaches the maximum value when the riser reaches the equilibrium position. Moreover, the local maximum transverse velocities occur at the peak CF amplitudes, and the values are relatively large when the vibration is in the resonance regions. The 3 D vortex columns are shed nearly parallel to the axis of the curved flexible riser. As the local Reynolds number increases from 0 at the bottom of the riser to the maximum value at the top, the wake undergoes a transition from a two-dimensional structure to a 3 D one. More irregular small-scale vortices appeared at the wake region of the riser, undergoing large amplitude responses.  相似文献   

Preface for the Special Volume on Exploration and Environmental Considerations of Deep Seabed Mineral Resources     

Kiseong Hyeong  Se-Jong Ju  David Billett  Ashley Rowden 《Ocean Science Journal》2018,53(2):285-286

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Correction to: Solar Radius at Subterahertz Frequencies and Its Relation to Solar Activity     

Fabian Menezes  Adriana Valio 《Solar physics》2018,293(6):89

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Walking Access Distance of Metro Passengers and Relationship with Demographic Characteristics: A Case Study of Nanjing Metro     

Jinliao He  Ruozhu Zhang  Xianjin Huang  Guangliang Xi 《中国地理科学(英文版)》2018,28(4):612-623

In the metropolises of China, the metro plays an increasingly important role in commuting because of its efficiency, affordability, and cleanliness. This paper attempts to explore the relationship between walking access distance to metro stations and the demographic characteristics of passengers, such as age, monthly income, travel frequency, gender, and travel purpose, as well as the influence of the urban context. Nanjing Metro Line 2 is selected as the case study. By using different methods such as a questionnaire survey, spatial decay function, analysis of covariance (ANOVA), network analysis of routes, and K-means cluster analysis, it is suggested that demographic characteristics have a significant impact on the pedestrian walking distance, with the exception of gender. Furthermore, the paper finds a spatial decay effect in walking access distance, the decay rate of which, however, varies across stations. Terminal stations have a larger pedestrian catchment area than in regular and exchange stations. Moreover, the passengers of Nanjing Metro Line 2 can be classified into six groups according to their demographic characteristics, among which education and occupation are vital indicators in determining their willingness to walk to the stations. Middle-class passengers have a higher dependence on the metro and tend to walk longer than other groups do. This study provides an important reference for planners and transport sectors to optimize land-use and transport infrastructures.  相似文献   

Long-term variability of air temperature and precipitation conditions in the Polish Carpathians     

Agnieszka Wypych  Zbigniew Ustrnul  Dirk R. Schmatz 《山地科学学报》2018,15(2):237-253

Mountain regions are sensitive to climate changes, which make them good indicators of climate change. The aim of this study is to investigate the spatial and temporal variability of air temperature and precipitation in the Polish Carpathians. This study consists of climatological analyses for the historical period 1851-2010 and future projections for 2021-2100. The results confirm that there has been significant warming of the area and that this warming has been particularly pronounced over the last few decades and will continue in the oncoming years. Climate change is most evident in the foothills; however, these are the highest summits which have experienced the most intensive increases in temperature during the recent period. Precipitation does not demonstrate any substantial trend and has high year-to-year variability. The distribution of the annual temperature contour lines modelled for selected periods provides evidence of the upward shift of vertical climate zones in the Polish Carpathians, which reach approximately 350 meters, on average, what indicates further ecological consequences as ecosystems expand or become extinct and when there are changes in the hydrological cycle.  相似文献   

Photosynthetic response of <Emphasis Type="Italic">Scirpus validus</Emphasis> and <Emphasis Type="Italic">Typha orientalis</Emphasis> to elevated temperatures in Dianchi Lake,Southwestern China     

Jun-ping Xu  Mei Sun  Hang Wang  Yun Zhang  Xiao-tang Zhang  Kun Tian 《山地科学学报》2018,15(12):2666-2675

Understanding the effects of simulated warming on photosynthetic performance of aquatic plants may provide strong supports for predicting future dynamics of wetland ecosystems in the context of climate change. The plateau wetlands located in Yunnan province are highly sensitive to climate warming due to their high altitude and cold temperature. Here, we conducted a temperaturecontrolled experiment using two temperature manipulations (ambient temperature as the control and 2°C higher than ambient temperature as the warmed treatment) to determine the photosynthetic characteristics of two lakeside dominant species (Scirpus validus Vahl and Typha orientalis C. Presl.) in Dianchi Lake. Net photosynthetic rate (P_n), stomatal conductance (G_s), intercellular CO₂ concentration (C_i), and transpiration rate of S. validus that grew under warmed treatment were all significantly higher than those under the control. G_s and C_i of T. orientalis showed similar patterns as S. validus did. For the response curves of P_n to photosynthetic active radiation (Pn-PAR) and intercellular CO₂ concentration (P_n-C_i), S. validus had higher P_n values under elevated temperatures than the control, while P_n-PAR and P_n-C_i curves of T. orientalis did not separate clearly under two temperature scenarios. Both S. validus and T. orientalis had higher maximum net photosynthetic rate, light saturation point, dark respiration rate, the maximum rate of RuBP carboxylation (V_cmax), maximum electron transport rate driving RuBP regeneration (J_max), the ratio of V_cmax to J_max, triosephosphate utilization, and 1, 5-bishosphate carboxylase ribulose content under warmed treatment than those under the control. This study provides a preliminary step for predicting the future primary production and vegetation dynamics of plateau wetlands in Yunnan province.  相似文献   

Regional Characteristics and Causes of Haze Events in Northeast China     

Weiwei Chen  Shichun Zhang  Quansong Tong  Xuelei Zhang  Hongmei Zhao  Siqi Ma  Aijun Xiu  Yuexin He 《中国地理科学(英文版)》2018,28(5):836-850

Northeast China experiences severe atmospheric pollution, with an increasing occurrence of heavy haze episodes. However, the underlying forces driving haze formation during different seasons are poorly understood. In this study, we explored the spatio-temporal characteristics and causes of haze events in Northeast China by combining a range of data sources(i.e., ground monitoring, satellite-based products, and meteorological products). It was found that the ‘Shenyang-Changchun-Harbin(SCH)'city belt was the most polluted area in the region on an annual scale. The spatial distribution of air quality index(AQI) values had a clear seasonality, with the worst pollution occurring in winter, an approximately oval-shaped polluted area around western Jilin Province in spring, and the best air quality occurring in summer and most of the autumn. The three periods that typically experienced intense haze events were Period I from mid-October to mid-November(i.e., late autumn and early winter), Period II from late-December to February(i.e., the coldest time in winter), and Period III from April to mid-May(i.e., spring). During Period I, strong PM_(2.5) emissions from seasonal crop residue burning and coal burning for winter heating were the dominant reasons for the occurrence of extreme haze events(AQI 300). Period II had frequent heavy haze events(200 AQI 300) in the coldest months of January and February, which were due to high PM_(2.5) emissions from coal burning and vehicle fuel consumption, a lower atmospheric boundary layer, and stagnant atmospheric conditions. Haze events in Period III, with high PM_(10) concentrations, were primarily caused by the regional transportation of windblown dust from degraded grassland in central Inner Mongolia and bare soil in western Jilin Province. Local agricultural tilling could also release PM_(10) and enhance the levels of windblown dust from tilled soil. Better control of coal burning, fuel consumption, and crop residue burning in winter and autumn is urgently needed to address the haze problem in Northeast China.  相似文献   

On the electron density diagnostics of silicon <Emphasis Type="SmallCaps">viii</Emphasis> ion in solar transition region     

Jian He  Qingguo Zhang 《Astrophysics and Space Science》2018,363(9):194

The conditions for accurate electron density diagnostics in the solar transition region are discussed, and result shows that lines from Si?viii can provide an excellent tool for electron density diagnostics of the emitting plasma. For the Si?viii 1440.50 Å and 1445.75 Å lines, the principle of the electron density diagnostics is discussed for any intensity ratio. By the observed intensity ratio, the diagnostic results of the electron density for the quiet sun and the active region are calculated, and results indicate that in the quiet sun, the averaged electron density is \(\log (N_{e}) = 8.63\); while in the active region, the averaged density gets the maximum \(\log (N_{e}) = 8.86\) in the active region (B), and gets the minimum \(\log (N_{e}) = 8.38\) in the active region (E), where the electron density is in the unit of cm^?3. Finally, the relationship of intensity ratio and electron density is discussed, in the case of lower and higher electron density limits. This discussion is significant in the electron density diagnostics, which will be important for study on coronal heating and acceleration of solar wind.  相似文献