Deep Valleys Research Articles

Tropical deciduous forest in Yunnan, southwestern China: Implications for geological and climatic histories from a little-known forest formation

In the southern mountain ranges of Yunnan province, China, deep valleys of several large rivers create rain shadows with hot dry summers, and are locally designated tropical; towards the north, notably in the Lancang (Upper Mekong) valley, these regions may experience frost during winter. The woody forest canopy of these valleys is predominantly deciduous, with evergreen elements in the north, where the canopy is open and the forest savanna-like. However, we here present tall forest with a closed deciduous canopy and semi-evergreen subcanopy observed in hot dry valleys of these rivers and their tributaries in the tropical south. The structure and physiognomy of these forests resemble the tall (moist) deciduous forest formation widespread in South Asia and Indo-Burma. Furthermore, these forests are largely composed of tropical elements at both the generic (80%) and the species level (>70%), indicating that these forests are indeed tropical. We originally hypothesized that these isolated forests represent refugia of a pre-Holocene extension of tall (moist) deciduous forest formation of South Asia and Indo-Burma. The sample plot we established to test this hypothesis confirmed that these forests share the structure and physiognomy of the tall (moist) deciduous forest formation; however, the plots also showed that these forests lack the characteristic and dominant species of the formation's Indo-Burmese range. The tree flora, in particular, indicates that both deciduous and evergreen elements are instead mostly derived from the adjacent tropical semi-evergreen forests of tropical southern China; yet they also include an important endemic element, which implies that these forests have survived as refuges possibly since the Pliocene. The exceptional representation of evergreen elements in these forests indicates that they have rarely been subject to hot fires or domestic cattle browsing, adding to the unique nature of the forests and further justifying their strict conservation.

Study on the Performances of an Approximating Spline Filter Based on the ADRF Function in Surface Roughness Evaluation

Isotropy is an important feature of an area filter in the three-dimensional surface roughness evaluation. First, the transmission characteristic deviation between the approximating spline filter and the Gaussian filter is reduced by cascading approximating. Second, the approximating spline filter is superimposed on the orthogonal direction to obtain an isotropic areal filter. Then, four direct methods for the solving approximating spline matrix are applied. Based on the profile filtering and areal filtering, the computational efficiency and accuracy are compared. The experimental results show that the improved square root method (LDLT decomposition) combines both computational efficiency and filtering precision, and is a good choice for solving the approximating spline matrix. Finally, six kinds of robust approximating spline filters are constructed. Taking the output value of robust Gaussian regression filter (RGRF) as reference, and the honing profile and step surface with deep valley characteristics were used as test surfaces to compare their robustness and iteration time. The experimental results show that the approximating spline filter based on the ADRF function has the shortest iteration times, while its roughness is close to the robust Gaussian regression filter.

Sedimentary environment of a dammed lake buried in the modern riverbed of the Yalong River during the Last Glacial Maximum and its implication for fluvial geomorphic evolution

Along the eastern margin of the Qinghai–Tibet Plateau, there are frequent occurrences of strong tectonic movement and large-scale landslides. River blockages often occur in deep-cut river valleys, forming large-scale dammed lakes. In this study, a ~26.5 m thick lacustrine sedimentary profile that underlying the modern riverbed of the Yalong River is reported. Here, 14C dating results show that lacustrine deposition began at ~25 ka and continued till ~10 ka, mainly during the Last Glacial Maximum. Paleoclimatic indicators, such as particle size, magnetic susceptibility, and spore-pollen combination, were used to reconstruct the evolution process of the paleoenvironment in the study area, revealing that a paleo-flood event occurred at ~19 ka. The Tongzilin dammed lake contains an excellent record of the geomorphic evolution of the lower reaches of the Yalong River during the Last Glacial Maximum. Before 25 ka, the Yalong River experienced strong downcutting to form a deep valley, which created the space conditions for the formation of the dammed lake; from 25 to 10 ka, the dammed lake remained relatively stable, with dominating accumulation; and after 10 ka, the dammed lake broke and the river continued to downcut.

Long-term behavior of earth pressure around a high-filled cut-and-cover tunnel

The Northwest Loess Plateau in China is mountainous and contains deep valleys which consist mostly of loess. Tunnels constructed in such deep valley and backfilled with soil are called high-filled cut-and-cover tunnels (HFCCT). Several studies have been conducted on HFCCT, but the creep behavior of loess backfill has not been fully explored. Post-construction settlement in loess is large, and it is difficult for stability to be reached in a short time. Therefore, it is necessary to predict long-term behavior of earth pressure around an HFCCT to ensure long-term safety. The primary purpose of this paper is to investigate changes in earth pressure and displacement of soil with time after the completion of the backfill process. This is achieved using FLAC3D software (finite difference method). The results show that discrepancies in soil settlement and surface settlement will gradually increase and eventually reach stability. The distribution and value of earth pressure also becomes redistributed. Meanwhile, influencing factors such as slope angle and valley width gradually weaken with time, and only affect the time needed to reach stability.

THE ROLE OF DEPOSITION TEMPERATURE ON PARTICLE SIZE, ROUGHNESS PARAMETERS, MAGNETIC AND STRUCTURAL FEATURES OF ELECTROCHEMICALLY GROWN Ni–Fe/ITO SAMPLES

In this work, the impact of the deposition temperature (DT) on the particle size, roughness parameters, coercive force, squareness and structural features of the Ni–Fe samples electrochemically deposited onto glasses covered with indium tin oxide (ITO) was researched. An increase in the DT from 20 to 40 °C led to a very slight increase in the Fe concentration of the samples, revealing that the effect of the DT on the chemical composition was insignificant. The crystal structure was a face–centered cubic (fcc) and the preferred growth orientation was in the [111] direction irrespective of the DT. The crystallization of the samples improved, the size of the crystallites increased and the strength of the [111] growth orientation diminished with the DT. An increment in the DT resulted in a strong enhancement in the particle size and surface roughness. Further surface analysis indicated that the sample surface had a well spread out height distribution at the DT of 40 °C, while the sample surfaces at lower DTs 20 and 30 °C had narrow height distributions. In addition to that, the peaks were found to be predominant on the sample surfaces at lower DTs (20 and 30 °C), whereas the deep valleys were predominant on the sample surface at the DT of 40 °C. Magnetic measurements confirmed the existence of a semi–hard magnetic property in all samples. Compared to other samples produced at lower DTs (20 and 30 °C), the Ni–Fe sample electroplated at the DT of 40 °C possessed the highest coercive force and squareness values. Moreover, the magnetic characteristics of the samples were compatible with their morphological and structural characteristics.

ВІДАПЕЛЯТИВНІ ОРОНІМИ ІСТОРИЧНОЇ УМАНЩИНИ АНТРОПОГЕННОГО ПОХОДЖЕННЯ

The aim of the article is to find out the motives for the nomination of some oronyms of the historical Uman region that covers certain districts of Cherkasy, Kirovohrad and Vinnytsia regions and tends to belong to Uman. It is important to analyze the names in the diachronic aspect (their usage from the first mentions in written texts to the present day). The study of onym material involves the use of scientific cognition methods, including descriptive one for sorting out oronyms taken from written texts of the seventeenth and nineteenth centuries and documents from Ukrainian archival institutions, comparative-historical – to establish the reasons for the nomination of land forms recorded in Uman region in the seventeenth century, diachronic – as a means of studying names in historical development. For the first time the oronymic factual material of Uman region of the 17th–19th centuries was introduced into scientific circulation and its structural word-forming and lexical-semantic features in the diachronic aspect are investigated. Given that such objects were renamed, oronyms usually had several variants, and even within the same document, different models of the name of a particular object were recorded. The names associated with the relief elements reflect the landscape diversity of the historical Uman region. The location in Central Ukraine contributed to the creation of an original natural complex of the study area. In proper names, this is expressed primarily in the use of geographical terminology. For the historical Uman region, the terms that have become proper names are beam, valley, grotto, levada, grave, and ravine. The transformation and transition of geographical nouns into microtoponyms take place on the basis of fixing the singularity and individuality of reality itself. But along with the onymization of the toponymic appellation in the microtoponymformation complex constructions have been involved, in the attributive part of which there are lexemes expressed in landscape terminology: Deep Valley; Thunder, or Lion's Grotto; Bloody ravine; The field of the industrious Yurentokh Kushnir. Most names for landforms contain a description of the physical and geographical properties of natural realities. Microtoponyms characterize the objects by their size, shape, and length. The appellative derived names of the historical Uman region which reflect the relief and landscape features of the area are divided into two groups: 1. Microtoponyms of naturogenic origin (reflect lowland terrain, elevated terrain, plain terrain, physical and geographical properties of the object (shape, size and other features of the denotation), indicate the metaphor, flora and fauna of the region); 2. Microtoponyms of anthropogenic origin (related to human activity). It was found that the studied names associated with the elements of relief, reflect not only the diversity of the landscape of the historical Uman region, but also indicate the occupation of the population, ethnic composition; related to the names of structures, buildings, facilities, roads and certain events and occasions. Most of them exist today only in scientific works, having disappeared from the speech of the locals, and some onyms have undergone partial linguistic and component changes during the history of their usage.

THE ROLE OF DEPOSITION TEMPERATURE ON PARTICLE SIZE, ROUGHNESS PARAMETERS, MAGNETIC AND STRUCTURAL FEATURES OF ELECTROCHEMICALLY GROWN Ni–Fe/ITO SAMPLES

In this work, the impact of the deposition temperature (DT) on the particle size, roughness parameters, coercive force, squareness and structural features of the Ni–Fe samples electrochemically deposited onto glasses covered with indium tin oxide (ITO) was researched. An increase in the DT from 20 to 40 °C led to a very slight increase in the Fe concentration of the samples, revealing that the effect of the DT on the chemical composition was insignificant. The crystal structure was a face–centered cubic (fcc) and the preferred growth orientation was in the [111] direction irrespective of the DT. The crystallization of the samples improved, the size of the crystallites increased and the strength of the [111] growth orientation diminished with the DT. An increment in the DT resulted in a strong enhancement in the particle size and surface roughness. Further surface analysis indicated that the sample surface had a well spread out height distribution at the DT of 40 °C, while the sample surfaces at lower DTs 20 and 30 °C had narrow height distributions. In addition to that, the peaks were found to be predominant on the sample surfaces at lower DTs (20 and 30 °C), whereas the deep valleys were predominant on the sample surface at the DT of 40 °C. Magnetic measurements confirmed the existence of a semi–hard magnetic property in all samples. Compared to other samples produced at lower DTs (20 and 30 °C), the Ni–Fe sample electroplated at the DT of 40 °C possessed the highest coercive force and squareness values. Moreover, the magnetic characteristics of the samples were compatible with their morphological and structural characteristics.

SPATIAL AND FUNCTIONAL DIVERSITY OF MOUNTAIN SETTLEMENTS: A CASE STUDY OF HAR KI DUN

Mountains have the most varied landscapes. There are deep valleys, densely wooded scarps and rolling pastureland (bugyals). The ‘geodiversity’ of the mountainous areas has given rise to a diversity of cultural landscapes. This diversity has also given rise to a diversity of settlements. Similar to the other mountainous areas the heterogeneous landscape of the high Himalayan region presents distinct types of settlements. These settlements are scattered, fragmented and vertically distributed. There is marked spatial and functional diversity in these settlements. This spatial and functional diversity of settlements is due to the diversity of the natural landscape. It is due to the diversity of terrain, climatic conditions and nature (or fertility) of the soil. The functional diversity of settlements is due to the differences in the suitability of the landscape for distinct land use. It is also due to the diversity of the socioeconomic factors; such as connectivity of the region. Furthermore, these spatially fragmented and functionally distinct parts of settlements present an integrated land use (functionally integrated land use), especially within a heterogeneous landscape. The aim of this research, therefore, is to define and describe the different types of landscapes that occur in the high Himalayan region. These landscapes sustain different (human) activities. It is an attempt to identify the functions of spatially distinct landscapes (i.e., production areas) of mountain settlements. The aim of this research is to explain how these landscapes are used differently. Another theme of this research is the spatial interdependence of settlements. It evaluates the relationship between landscape diversity and the land suitability for crop production or animal husbandry and other land use of these spatially distinct and different areas of mountain settlements. It evaluates the functionality (and functional relationship) of these settled spaces.

Structural characteristics of the KPR-CBR triple-junction inferred from gravity and magnetic interpretations, Philippine Sea Plate

The intersection of the Kyushu-Palau Ridge (KPR) and the Central Basin Rift (CBR) of the West Philippine Basin (WPB) is a relic of a trench-trench-rift (TTR) type triple-junction, which preserves some pivotal information on the cessation of the seafloor spreading of the WPB, the emplacement and disintegration of the proto-Izu-Bonin-Mariana (IBM) Arc, and the transition from initial rifting to steady-state spreading of the Parece Vela Basin (PVB). However, the structural characteristics of this triple-junction have not been thoroughly understood. In this paper, using the newly acquired multi-beam bathymetric, gravity, and magnetic data obtained by the Qingdao Institute of Marine Geology, China Geological Survey, the authors depict the topographic, gravity, and magnetic characteristics of the triple-junction and adjacent region. Calculations including the upward continuations and total horizontal derivatives of gravity anomaly are also performed to highlight the major structural features and discontinuities. Based on these works, the morphological and structural features and their formation mechanisms are analyzed. The results show that the last episode amagmatic extension along the CBR led to the formation of a deep rift valley, which extends eastward and incised the KPR. The morphological and structural fabrics of the KPR near and to the south of the triple-junction are consistent with those of the western PVB, manifesting as a series of NNE-SSW- and N-S-trending ridges and troughs, which were produced by the extensional faults associated with the initial rifting of the PVB. The superposition of the above two reasons induced the prominent discontinuity of the KPR in deep and shallow crustal structures between 15°N–15°30′N and 13°30′N–14°N. Combined with previous authors’ results, we propose that the stress produced by the early spreading of the PVB transmitted westward and promoted the final stage amagmatic extension of the CBR. The eastward propagation of the CBR destroyed the KPR, of which the magmatism had decayed or ceased at that time. The destruction mechanism of the KPR associated with the rifting of the PVB varies along strike the KPR. Adjacent to the triple-junction, the KPR was destroyed mainly due to the oblique intersection of the PVB rifting center. Whereas south of the triple-junction, the KPR was destroyed by the E-W-directional extensional faulting on its whole width.©2021 China Geology Editorial Office.

ПОДІЛЬСЬКЕ ПРИДНІСТЕР'Я, ЯК МОДЕЛЬНИЙ РЕГІОН ДЛЯ РОЗВИТКУ ЕКСТРЕМАЛЬНОГО ТУРИЗМУ

The purpose of the study – substantiate the possibilities for the development of extreme tourism within the Transnistria of Podillia, taking into account modern socio-economic conditions and the state of natural conditions and resources of the region. Research methodology. Analysis and generalization of available literary and cartographic sources and materials of own field landscape and tourism research using the principles of historicism and natural-anthropogenic combination. Processing, storage and visualization of analytical information by geoinformation methods using Delta software (version 5). Results. It is shown that the development of extreme tourism within the Transnistria of Podillia is facilitated by the «low-mountain» landscape in the structure of which there are deep (up to 200-220 m) canyon-like valleys of the Dniester and its left tributaries, almost «mountainous character» of rivers with waterfalls and numerous rapids, unique climatic conditions and vegetation. The relief and its forms are of particular importance for the development of extreme tourism here: the absolute heights of the surface decrease from north to south from 340 to 100 m, and the depth of incision of canyon-like river valleys from 60 to 220 m. The presence of steep (up to 400) slopes and cliffs up to 20 m high. The nature and landscape of Transnistria of Podillia is everywhere supplemented by numerous historical and architectural monuments, and is also reflected in the numerous and original traditions and customs of the local population. All together, it makes it possible to develop the tourism and recreational sphere, and extreme tourism in its structure, much more actively within the Transnistria of Podillia. Scientific novelty. Its essence is in a complex descriptionof natural and socio-economic conditions of Transnistria of Podillia suitable for the development of various types of extreme tourism, substantiation of their development, identification of priority types of extreme tourism in modern conditions and in the future. various types of extreme tourism, including training for children of middle and senior school age. The Tovtry of Podillia and Murafa are kind of «extreme» rest for elderly, especially a section of the Grand Canyon of the Dniester, the Kremenets and Podillia Mountains, the hollow sections of the channel of the Southern Bug and its tributaries.Their development in order to develop extreme types of tourism requires further detailed recreational and tourist research. Practical significance. The development of such types of extreme tourism as hot air ballooning, delta and paragliding tourism, parachuting, equestrian sports, Bicycle and hiking tourism, rafting tourism in the future, kayaking and jailoo tourism, hunting tourism and water tourism is justified. Territories in the area of the towns of Zalishchyky, Khotyn, Novodnistrovsk towns, as well as villages confined to the Dniester valley (Okopy, Bila, Busha) and its tributaries (Nyrkiv, Zavallia, Zaluchia, Stina) have similar natural and social conditions to this center of aeronautics. The rest of these types of extreme tourism, although developing within the Transnistria of Podillia, but still at a slow pace. Types of limited development include such types of extreme tourism as jail tourism, motorcycle racing in deserted terrain and extreme racing. It is noted that gradually extreme tourism can become a leader in the development of tourism and recreation not only in Transnistria of Podillia but also Podillia in general. This will allow not only to use more rationally public funds and funds of local communities, which are already allocated for the development of certain types of extreme tourism, jailoo tourism, motorcycle racing and extreme racing are classified as limited development but also to streamline their spontaneous manifestation and prevent injuries.

Yampa River-Colorado River Drainage Divide Origin Determined from Topographic Map Evidence, Southern Routt County, Colorado, USA

Detailed topographic map evidence and a new Cenozoic geologic and glacial history paradigm are used to determine the previously unexplained Yampa River-Colorado River drainage divide origin. The Yampa River now flows in a north direction away from the Colorado River (between the Park Range to the east and the Flat Tops region to the west) before turning in a west direction to reach the Unita Mountains where it joins the south-oriented Green River, which eventually joins the southwest-oriented Colorado River. Topographic maps show the Yampa-Colorado River drainage divide is asymmetric with steeper slopes leading to the Colorado River, barbed (south-oriented) tributaries leading to north-oriented Yampa River headwaters (especially near the Yampa River turn to the west), and evidence of a large north-to-south oriented diverging and converging channel complex that preceded present-day drainage routes. Map evidence is interpreted to mean massive south-oriented floods flowed through what are now north-oriented Yampa River headwaters valleys and that headward erosion of a deep west-oriented valley beheaded and reversed those south-oriented flood flow channels to create the north-oriented Yampa River headwaters and the Egeria Park area Yampa-Colorado River drainage divide seen today. Large south-oriented floods leading to the Colorado River (while regional uplift was occurring) are inconsistent with accepted Cenozoic geologic and glacial history paradigm predictions, but are predicted by a newly proposed Cenozoic geologic and glacial history paradigm in which a thick continental ice sheet created a deep “hole” by eroding underlying bedrock and also by causing crustal warping that raised the present-day northern Colorado east-west continental divide as immense south-oriented meltwater floods flowed across it.

Evolution of Dam Lakes in the Kayanga/Geba Basin: Contribution of Remote Sensing and GIS

The Confluent and Niandouba dams were built in 1984 and 1997 respectively to better control water resources, increase agricultural production and promote local development. This article studies their evolution on the Kayanga/Geba River, a transboundary river between Guinea, Senegal and Guinea-Bissau, from its impoundment to the present day. The topographic characteristics analysed through the DTMs (Digital Terrain Models) show a flat shape for the Confluent Dam Lake and long plateaus for the Niandouba Dam Lake. The cross-sections present a variety of morphologies ranging from wide U-shaped valleys with sinuous bottoms to deep V-shaped valleys. The homogenisation and reconstruction of missing values were carried out using the regional vector method. The application of Pettitt’s statistical test on annual rainfall (1932-2019) indicates breaks of stationarity in 1967 or 1969. The post-breakage deficits range from 11.4% to 19.4%. The segmentation method corroborates the results of the Pettitt test. The variations of the surface area of the Confluent and Niandouba water bodies are linked to rainfall, evaporation and withdrawals for different uses. Their monitoring would allow for better management of available water resources but also for good planning of off-season crops.

Vortex induced vibration and its controlling of long span Cross-Rope Suspension transmission line with tension insulator

Long span cross-rope suspension structure is an innovative structural system evolved from typical Cross-Rope Suspension (CRS) guyed tower, a type of supporting system with short span suspension cable supporting overhead power transmission lines. In mountainous areas, the span length of suspension cable was designed to be extended to hundreds or over one thousand meters, which is applicable for crossing deep valleys. Vortex Induced Vibration (VIV) of overhead power transmission lines was considered to be one of the major factors of its fatigue and service life. In this paper, VIV and its controlling by Stockbridge damper for long span CRS was discussed. Firstly, energy balance method and finite element method for assessing VIV of CRS were presented. An approach of establishing FE model of long span CRS structure with dampers was introduced. The effect of Stockbridge damper for overall vibration of CRS was compared in both theoretical and numerical approaches. Results indicated that vibration characteristics of conductor in long span CRS compared with traditional tower-line system. Secondly, analysis on long span CRS including Stockbridge damper showed additional dampers installed were essential for controlling maximum dynamic bending stresses of conductors at both ends. Moreover, factors, including configuration and mass of Stockbridge damper, span length of suspension cable and conductor and number of spans of conductor, were assessed for further discussion on VIV controlling of long span CRS.

An experimental and theoretical study of the abrasion performance of digital light processing parts

Generally, interactions at surface asperities are the cause of wear. Two-Thirds of wear in industry occurs because of the abrasive or adhesive mechanisms. This research presents an analytical model for abrasion of additive manufactured Digital Light Processing products using pin-on-disk method. Particularly, the relationship between abrasion volume, normal load, and surface asperities’ angle is investigated. To verify the proposed mathematical model, the results of this model are verified with the practical experiments. Results show that the most influential parameters on abrasion rate are normal load and surface’s normal angle. Abrasion value increases linearly with increasing normal load. The maximum abrasion value occurs when the surface’s normal angle during fabrication is 45°. After the asperities are worn the abrasion volume is the same for all specimens with different surface’s normal angle. Though layer thickness does not directly affect the wear rate, but surface roughness tests show that layer thickness has a great impact on the quality of the abraded surface. When the thickness of the layers is high, the abraded surface has deeper valleys, and thus has a more negative skewness. This paper presents an original approach in abrasion behavior improvement of DLP parts which no research has been done on it so far; thus, bringing the AM one step closer to maturity.

Climate of the Gilgit-Baltistan Province, Pakistan

The present study focuses on the climate conditions of Gilgit Baltistan. It includes the distribution ofdifferent weather elements like precipitation, temperature, number of rainy days, humidity, wind speed, air pressure,evapotranspiration, sunshine, factors affecting climate, and climate classification. Due to glaciation, the area is badlyeroded and consists of deep valleys and moraines. There is a marked variability between the climates of the eastern andwestern observatories of the area. Mostly, terrace agriculture is practiced in the area with deciduous and alpine forests.Based on temperature, the area has been divided into three distinct climate regions, namely, mild, cool, and cold.Whereas, based on precipitation, it classified into arid, semi-arid and undifferentiated highlands. Chilas is the hottestarea of the province, while Astor and Skardu are the coldest. The study area receives heavy precipitation from localthunderstorms, particularly during April and May. There are four rainy seasons, namely winter, pre-monsoon,monsoon, and post monsoon precipitation. The highest precipitation in the area is observed at Astore, while the lowestat Gupis. The relative humidity is below 55% throughout the year and causes chill with low temperature and crackingin human skins. Based on the variability of weather elements, the province has been divided into three macro, threemeso and six micro climate regions.

The topographic evolution of the Tibetan Region as revealed by palaeontology

The Tibetan Plateau was built through a succession of Gondwanan terranes colliding with Asia during the Mesozoic. These accretions produced a complex Paleogene topography of several predominantly east–west trending mountain ranges separated by deep valleys. Despite this piecemeal assembly and resultant complex relief, Tibet has traditionally been thought of as a coherent entity rising as one unit. This has led to the widely used phrase ‘the uplift of the Tibetan Plateau’, which is a false concept borne of simplistic modelling and confounds understanding the complex interactions between topography climate and biodiversity. Here, using the rich palaeontological record of the Tibetan region, we review what is known about the past topography of the Tibetan region using a combination of quantitative isotope and fossil palaeoaltimetric proxies, and present a new synthesis of the orography of Tibet throughout the Paleogene. We show why ‘the uplift of the Tibetan Plateau’ never occurred, and quantify a new pattern of topographic and landscape evolution that contributed to the development of today’s extraordinary Asian biodiversity.

Profiling novel high-conductivity 2D semiconductors

When complex mechanisms are involved, pinpointing high-performance materials within large databases is a major challenge in materials discovery. We focus here on phonon-limited conductivities, and study 2D semiconductors doped by field effects. Using state-of-the-art density-functional perturbation theory and Boltzmann transport equation, we discuss 11 monolayers with outstanding transport properties. These materials are selected from a computational database of exfoliable materials providing monolayers that are dynamically stable and that do not have more than six atoms per unit cell. We first analyze electron-phonon scattering in two well-known systems: electron-doped InSe and hole-doped phosphorene. Both are single-valley systems with weak electron-phonon interactions, but they represent two distinct pathways to fast transport: a steep and deep isotropic valley for the former and strongly anisotropic electron-phonon physics for the latter. We identify similar features in the database and compute the conductivities of the relevant monolayers. This process yields several high-conductivity materials, some of them only very recently emerging in the literature (GaSe, Bi2SeTe2, Bi2Se3, Sb2SeTe2), others never discussed in this context (AlLiTe2, BiClTe, ClGaTe, AuI). Comparing these 11 monolayers in detail, we discuss how the strength and angular dependency of the electron-phonon scattering drives key differences in the transport performance of materials despite similar valley structure. We also discuss the high conductivity of hole-doped WSe2, and how this case study shows the limitations of a selection process that would be based on band properties alone.

Considering frictional slippage at saddle-cable interface in seismic behavior of a suspension bridge

Long-span suspension bridges are widely used in deep valleys, which face severe seismic risk. However, the potential saddle-cable frictional slippage under earthquake excitation as well as its influence on the seismic response of the whole suspension bridge has not yet been investigated. To investigate the effect of frictional slippage at the saddle-cable interface, this paper developed a nonlinear numerical model that considers the saddle-cable slippage. Another contrasting model with a non-slipping saddle-cable interface was used for quantitative comparison. Nonlinear dynamic analyses were conducted using these two models. The saddle-cable interfacial response indicated the realization of the frictional slippage at the saddle-cable interface under the maximum considered earthquake. The overall damage patterns, critical sectional performance, main girder drift, and energy dissipation were discussed in detail. Under the design based and maximum considered intensities, the saddle-cable slippage was seldom observed. The visible frictional slippage was encountered only at ultimate safety earthquake, which could be helpful to limit the transferred load, protect the pylon from yielding, and dissipate approximately 14% of the input seismic energy. While the slippage could not evidently affect the overall deformation pattern of the suspension bridge, as well as the response of bearings and central buckles.

Design and Implementation of Electric Power Patrol Monitoring System Based on Beidou and Mobile Network

Most existing communication technologies used for power inspection systems cannot seamlessly cover the inspection line range. Therefore, the real-time transmission of inspection information and the safety of personnel are difficult to guarantee. Based on current research on electric power inspection and the industry’s urgent need for real-time and accurate location information of inspectors, this paper designed and developed an electric power patrol and monitoring system using the Beidou satellite system in conjunction with mobile networks. The problem of patrolling information in blind areas where ground communications cannot be reached in real time is effectively solved through a seamless switching design between Beidou short messages and mobile networks. The short message broadcast and high-precision position information return of inspection personnel were also realized by applying the Beidou multi-mode data transmission module as independently developed. The system took advantage of the user and function-oriented conceptual design and the Browser/Server (B/S)-based architecture design, as well as the combination with the SpringMVC + Spring + MyBatis (SSM) to improve the quality of the development process. Some key functions, such as real-time position display, track playback, user information management, and other functions, are interactive with the implemented visual user interfaces, which fundamentally helps the power monitoring department provide remote visual supervision services. The test results of the core module showed that the system could be used as a supplement to the power inspection and supervision industry, especially for deep mountain valleys, dense forests, and other areas without stable communication signals.

Retrieval of Land Surface Temperature With Topographic Effect Correction From Landsat 8 Thermal Infrared Data in Mountainous Areas

Accurate estimation of land surface temperature (LST) is crucial for ecological environment monitoring and climate change studies in mountainous areas. The current LST retrieval algorithms were developed without accounting for the topographic effect, which can only be used to retrieve LST over relatively flat surfaces. Due to the impact of 3-D structure of mountainous surfaces, rugged terrain makes the processes of thermal radiation more complex. In this study, a radiative transfer equation (RTE)-based single-channel algorithm was proposed to retrieve LST with topographic effect correction from the Landsat 8 thermal infrared (TIR) data in mountainous areas. This algorithm accounts for the changes in the thermal radiation components in the TIR RTE caused by the topographic effect. According to the analysis of simulation data, sky-view factor (SVF), atmospheric water vapor content, surface emissivity of target pixel, and average LST of the surrounding terrain have significant influence on the magnitude of the topographic effect. The differences between the LST retrieved without/with topographic effect correction from the Landsat 8 TIR data are related to SVF. The topographic effect should be taken into account in the LST retrieval algorithm when SVF is smaller than 0.7. The largest LST difference of approximately 1 K occurs in the deep valley. The results indicate that LST without topographic effect correction could be overestimated to be as high as 1 K. Due to a lack of <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">in situ</i> LST measurements, the performance of the LST retrieval algorithm in mountainous areas was only evaluated by comparing the brightness temperature (BT) at the top of the atmosphere (TOA) simulated by the DART+MODTRAN model and the TIR RTE over mountainous surfaces at three subregions. There is a good consistency between BT at the TOA simulated by the DART+MODTRAN model and the TIR RTE over mountainous surfaces at the three subregions, with a root-mean-squared error (RMSE) of less than 0.23 K.