Search

The capability to predict catastrophic failures and anticipate challenges relating to trafficability enables quadruped robots to adjust their planned trajectory in time to prevent any damages. In this paper, an estimation‐based method is proposed to describe the validity of the trajectory from the viewpoint of the traction performance of the terrain. The main contribution of this study lies in equipping quadruped robots with the ability to comprehend the strength characteristics of the terrain and assess the validity of trajectory planning by anticipating potential catastrophic motion failures. To this end, a novel perception method of the foot terrain interface based on proprioception is proposed to estimate terrain strength parameters. The vehicle–terrain traction model is extended to a legged locomotion pattern to estimate the traction limits of the terrain. The trafficability anticipation is driven by combining the traction limits of the terrain and the expected ground reaction force, as obtained by the model‐based predictive methods. The validity of this method is verified using a quadruped robot test platform. Results highlight the potential of the presented approach, in which the anticipation of trafficability, grounded in the understanding of the terrain strength, serves as the explicit foundation for altering trajectories to avert motion failure. [ABSTRACT FROM AUTHOR]

To reduce the structural deterioration of mass concrete structures from temperature cracks, and lower energy consumption caused by the traditional mass concrete hydration heat cooling process, this paper reports the preparation of concrete temperature-controlled phase change aggregate (PCA) by a vacuum compaction method using light and high-strength black ceramite and No. 58 fully refined paraffin wax as phase change material (PCM), and the encapsulation technology of the aggregate by using superfine cement and epoxy resin. Further, through laboratory tests, the cylinder compressive strength, thermal stability and mixing breakage rate of the encapsulated PCA were tested, and the differences in mechanical properties such as compressive strength, flexural strength and splitting tensile strength between phase change aggregate concrete (PCAC) and ordinary concrete were studied. A test method was designed to test the heat storage effect of PCA, and the temperature control effect of PCAC was analyzed based on the law of conservation of energy. The research conclusions are as follows: (1) Both superfine cement and epoxy resin shells increase the strength of the aggregate, with the epoxy resin increasing it more than the superfine cement. The thermal stabilization of the PCA is good after encapsulation of superfine cement and epoxy resin. However, PCA encapsulated in superfine cement is more easily crushed than that encapsulated in epoxy resin. (2) Under the condition of water bath heating and semi-insulation, when the water bath temperature reaches 85 °C, the temperature difference between the PCA and the common stone aggregate can be up to 6 °C. Based on the law of energy conservation, the test results will be converted to mass concrete with the same volume of aggregate mixture;, the difference of PCAC and ordinary concrete temperature can be up to 10 °C, so the temperature control effect is significant. (3) The mechanical properties of PCAC with 100% aggregate replacement rate compared to ordinary concrete are reduced to varying degrees, and the performance decline of the epoxy-encapsulated PCA is smaller than that encapsulated with superfine cement; in an actual project, it is possible to improve the concrete grade to make up for this defect. [ABSTRACT FROM AUTHOR]

Nerve guidance conduits (NGCs) have become a promising alternative for peripheral nerve regeneration; however, the outcome of nerve regeneration and functional recovery is greatly affected by the physical, chemical, and electrical properties of NGCs. In this study, a conductive multiscale filled NGC (MF‐NGC) consisting of electrospun poly(lactide‐co‐caprolactone) (PCL)/collagen nanofibers as the sheath, reduced graphene oxide /PCL microfibers as the backbone, and PCL microfibers as the internal structure for peripheral nerve regeneration is developed. The printed MF‐NGCs presented good permeability, mechanical stability, and electrical conductivity, which further promoted the elongation and growth of Schwann cells and neurite outgrowth of PC12 neuronal cells. Animal studies using a rat sciatic nerve injury model reveal that the MF‐NGCs promote neovascularization and M2 transition through the rapid recruitment of vascular cells and macrophages. Histological and functional assessments of the regenerated nerves confirm that the conductive MF‐NGCs significantly enhance peripheral nerve regeneration, as indicated by improved axon myelination, muscle weight increase, and sciatic nerve function index. This study demonstrates the feasibility of using 3D‐printed conductive MF‐NGCs with hierarchically oriented fibers as functional conduits that can significantly enhance peripheral nerve regeneration. [ABSTRACT FROM AUTHOR]

As a kind of large-scale connectivity infrastructure, submarine cables play a vital role in international telecommunication, socio-economic development and national defense security. However, the current understanding about the spatial pattern of global submarine cable network is relatively limited. In this article, we analyze the spatial distribution and connectivity pattern of global submarine cables, and identify their strategic pivots and strategic channels. The main conclusions are as follows: (1) The spatial distribution of global submarine cables is significantly unbalanced, which is characterized by the facts that the distribution of submarine cable lines is similar to that of sea lanes, and the agglomerations of landing stations are distributed unevenly along the coastline. (2) The connectivity pattern of global submarine cable network has a significant scale effect. At the micro, meso and macro scales, the connectivity structure presents chain model, cluster model and hub-and-spoke model, respectively. (3) The distribution of strategic pivots and strategic channels shows a pyramidal hierarchical feature. Singapore ranks highest among all the strategic pivots, while the Gulf of Aden and the Strait of Malacca rank highest among the strategic channels. Based on the identification of strategic pivots and channels, six strategic regions have been divided, which face various network security risks and need special attention and vigilance. [ABSTRACT FROM AUTHOR]

The purpose of this study was to use the neural network to distinguish optic edema (ODE), and optic atrophy from normal fundus images and try to use visualization to explain the artificial intelligence methods. Three hundred and sixty-seven images of ODE, 206 images of optic atrophy, and 231 images of normal fundus were used, which were provided by two hospitals. A set of image preprocessing and data enhancement methods were created and a variety of different neural network models, such as VGG16, VGG19, Inception V3, and 50-layer Deep Residual Learning (ResNet50) were used. The accuracy, recall, F1-score, and ROC curve under different networks were analyzed to evaluate the performance of models. Besides, CAM (class activation mapping) was utilized to find the focus of neural network and visualization of neural network with feature fusion. Our image preprocessing and data enhancement method significantly improved the accuracy of model performance by about 10%. Among the networks, VGG16 had the best effect, as the accuracy of ODE, optic atrophy and normal fundus were 98, 90, and 95%, respectively. The macro-average and micro-average of VGG16 both reached 0.98. From CAM we can clearly find out that the focus area of the network is near the optic cup. From feature fusion images, we can find out the difference between the three types fundus images. Through image preprocessing, data enhancement, and neural network training, we applied artificial intelligence to identify ophthalmic diseases, acquired the focus area through CAM, and identified the difference between the three ophthalmic diseases through neural network middle layers visualization. With the help of assistant diagnosis, ophthalmologists can evaluate cases more precisely and more clearly. [ABSTRACT FROM AUTHOR]

In recent years, with the continuous expansion of the global cruise tourism market, global and regional cruise shipping networks have gradually formed and improved. Among them, the Caribbean cruise shipping network is particularly mature and complex, with a typical regional spatial organization. This paper takes cruise routes as the starting point to analyze the basic characteristics of the Caribbean cruise shipping network, investigate their hierarchical structure and spatial differentiation characteristics, and summarize the general spatial laws of a regional cruise shipping network. The results show that Caribbean cruise routes are mostly circular, and some of them have multi-circular sections. Medium and short cruise routes are common, and most cruise routes usually include sailings that last for a week. The cruise network forms an inverted V shape with the Florida Peninsula as the core connecting the eastern and western Caribbean Seas. There are differences in the number of sailings and centrality of different ports, thus forming the functional differentiation of core hub ports, functional hub ports, and general ports. The Caribbean cruise shipping network is divided into different hierarchies; with the increasing complexity of hierarchies, the numbers of ports and shipping groups have increased, the number of sailings and the centrality show rising trends, and the structure of the cruise shipping network tends to be complicated and the coverage tends to be broad. The three hierarchies basically reflect the core, skeleton, and overall pattern of the Caribbean regional cruise shipping network, and the core hierarchy includes most of the core hub ports. [ABSTRACT FROM AUTHOR]

Parks are an important place for residents to relax. An equitable distribution of parks can promote social equity and enhance the residents' welfare. The service areas of parks are affected by the mode of transport. As public transport is a green and economic travel mode with a wide range of applications, we identified the service area of parks based on the accessibility of public transport. On this basis, the problem of park layout was analyzed. The results show that: (1) the coverage rate for the park service areas decreased from the center of Beijing to the periphery. The subdistricts around employment districts have a high coverage of park services, whereas some suburban subdistricts lack services. (2) The spatial form of PSAs can be affected by factors such as railways, water courses, and the topography, so there are service gaps for some 48 parks, which are mainly located outside the Fourth Ring Road area. (3) A poor allocation of public transport resources has aggravated the uneven distribution of the park services. Areas with few parks also have poor public transportation conditions. [ABSTRACT FROM AUTHOR]

Submarine cable network is one of the most important connectivity infrastructures in the digital era. In the past 20 years, the submarine cable network of Chinese mainland has formed a complex connectivity structure. This paper focuses on exploring the structure and evolution of the submarine cable network of Chinese mainland. The results show that the evolution can be divided into four stages: an initial stage (1993–1998), a developmental stage (1999–2002), a stagnation stage (2003–2015) and an accelerated stage (2016–2018). The connectivity structure can be analyzed at micro, meso and macro scales. Statistically, the connectivity increased significantly overall, but showed significant differences in space. For the microscale, the landing cities were characterized by "extensive but low, exclusive and high"; for the mesoscale, the connectivity of countries or regions was characterized by "distance attenuation" as a whole, but, in part, by a "regional identity"; for the macroscale, intercontinental connectivity differences have been declining. The hierarchy has been upgraded from a "3 system" to a "2 + 3 system". Finally, this paper discusses the interaction between submarine cable network construction and international relations, and puts forward policy suggestions for China's submarine cable construction. [ABSTRACT FROM AUTHOR]

The study presented a Monte Carlo simulation of light transport in eight commonly used filtered facepiece respirators (FFRs) to assess the efficacy of UV at 254 nm for the inactivation of SARS‐CoV‐2. The results showed different fluence rates across the thickness of the eight different FFRs, implying that some FFR models may be more treatable than others, with the following order being (from most to least treatable): models 1512, 9105s, 1805, 9210, 1870+, 8210, 8110s and 1860, for single side illumination. The model predictions did not coincide well with some previously reported experimental data on virus inactivation when applied to FFR surfaces. The simulations predicted that FFRs should experience higher log reductions (>>6‐log) than those observed experimentally (often limited to ~5‐log). Possible explanations are virus shielding by aggregation or soiling, and a lack of the Monte Carlo simulations considering near‐field scattering effects that can create small, localized regions of low UV photon probability on the surface of the fiber material. If the latter is the main cause in limiting practical UV viral decontamination, improvement might be achieved by exposing the FFR to UV isotropically from all directions, such as by varying the UV source to the FFR surface angle during treatment. [ABSTRACT FROM AUTHOR]

The ostrich (Struthio camelus) is characterized by high speed and heavy load when running. Its intertarsal joint (Fig. 1A) with double-nutrient foramina (DNF) exhibits excellent ability to withstand high impact during running, and is characterized by lightweight. We investigated the effect of DNF on the biomechanical properties of the intertarsal joints of the ostrich. The intertarsal joint was reconstructed according to computed tomography images, and four models were established to uncover the separate and combined effects of the compositional parameters (geometric features, material properties) on stress concentration reduction. We have revised the formula that can be used to predict the elasticity modulus (E) of ostrich bones and verified the accuracy of the formula with nano-indentation equipment. The results were analyzed by t tests, and the p value is less than 0.05. The finite element analysis was performed to evaluate the mechanical properties of the PT and models. Compared to the Filled model (DNF was filled), the maximum stress at the lateral and medial fossa in the Initial model was reduced by 15.4%, although there was no significant difference in the medial maximum stress. Compared with the stress value of models without holes, the models with holes have lower stress, with a reduction of 4.0%. Reasonable design of holes can improve the efficiency of material utilization. This paper investigated the mechanism of high mechanical properties of the intertarsal joints of ostrich and developed four bionic-bearing parts based on the characteristics of DNF and heterogeneity materials, which may provide ideas for the design of aircraft and robot parts with lightweight and high strength. [ABSTRACT FROM AUTHOR]

African ostriches are good at running in the desert, and their toenails can effectively improve the tractivetraction performance in the running process. To improve the tractivetraction trafficability of wheels on the lunar surface loose soil, a wheel with bionic wheel lugs was designed based on the bionic prototype of ostrich toenail and bionic engineering technology. Then, the rolling of the bionic wheel was simulated by using the three-dimensional (3D) discrete element method (DEM) simulation system of the interaction between irregular structure wheel and lunar soil, and the result was compared with that of the wheel with rectangular wheel lugs. Under the same working condition, the drawbar pull, torque, and sinkage of two kinds of wheels at slip ratios of 0.25, 0.375, and 0.625 were analyzed. The simulation results showed that the average drawbar pull and average torque of the bionic wheel are greater than that of the wheel with rectangular wheel lugs at three kinds of slip ratios. When the slip ratios were 0.25 and 0.375, there was almost no difference in the average sinkage of the two kinds of wheels, but the average sinkage of the bionic wheel was significantly less than that of the wheel with rectangular wheel lugs when the slip ratio was 0.625. The results show that, compared with the wheel with rectangular wheel lugs, the bionic wheel has better tractivetraction and anti-subsidence performance. This study provides a new design and research method for improving the tractive trafficability of wheels in the lunar loose surface environment. [ABSTRACT FROM AUTHOR]

Affected by climate and natural conditions, cruise activities have obvious seasonal characteristics. For a cruise ship, seasonality consists of the systematic, although not necessarily regular, movement of a cruise ship in a selected time. To examine more specifically the natural factors of the seasonal characteristics from a microscopic perspective, we construct month-temperature, quarter-season, and year-climate zone, a seasonal analysis framework in two dimensions of space and time and using a single world cruise ship named Queen Elizabeth (QE) as the case. Comparing the characteristics of the trajectory network with the seasonal factors, we find the cruise ship tend to voyage in a stable temperature range of 10°C–20°C, flee the winter and catch up with the summer and spring, and mainly stay in the temperature maritime climate zone, the subtropical monsoon humid climate zone, and the Mediterranean climate zone to form several branch network. Finally, the academic and practical implications of the research findings for seasonal management and itinerary choice are elaborated from the supply-side and demand-side. [ABSTRACT FROM AUTHOR]

The submarine optical-fiber cable (submarine cable) is a large connectivity infrastructure, which plays an important role in international communication, cyber-physical systems, and even national security. Although submarine cable network interruption may cause serious consequences, researching its vulnerability has not attracted much attention. This paper proposes a quantitative method to measure the vulnerability of the submarine cable network and evaluates the influence of the upcoming trans-Arctic cable (TAC) system on the submarine cable network of mainland China. To address this issue, first, the submarine cable network of mainland China is constructed. Further, methodology based on complex network and geospatial perspective is proposed to simulate the changes of network eigenvalues under different attacks and to quantitatively analyze the variation degree of network vulnerability. With the proposed method, the vulnerability of the submarine cable network of mainland China before and after construction of the trans-Arctic cable system is compared. The results reveal the key node countries and sea channels of the submarine cable network of mainland China and show the significance of the TAC system. [ABSTRACT FROM AUTHOR]

This study presents numerical simulations of UVC light propagation through seven different filtered face respirators (FFR) to determine their suitability for Ultraviolet germicidal inactivation (UVGI). UV propagation was modeled using the FullMonte program for two external light illuminations. The optical properties of the dominant three layers were determined using the inverse adding doubling method. The resulting fluence rate volume histograms and the lowest fluence rate recorded in the modeled volume, sometimes in the nW cm−2, provide feedback on a respirator's suitability for UVGI and the required exposure time for a given light source. While UVGI can present an economical approach to extend an FFR's useable lifetime, it requires careful optimization of the illumination setup and selection of appropriate respirators. [ABSTRACT FROM AUTHOR]

The railway is an indispensable feature of a nation's infrastructure, and the gauge is an internal and objective technical regulation of the railway. In the large-scale regional space, the track gauges reflect the development differences, historical relations and mutual influences between countries and regions. This makes the railway, originally as a regional connection, have special social, political, military and other multiple attributes. Based on this, the paper, from the perspective of railway gauge, takes the Eurasian continent as the case region to explore the spatial pattern, formation mechanism and organizational mode of communication of the Eurasian continental railway geo-system. The results show that 11 kinds of railway gauge structures exist in Eurasia, which respectively belong to three types of wide-gauge, standard-gauge, and narrow-gauge, but the mainstream gauge only includes 1520 mm, 1435 mm and 1067 mm. Considerable variation in the coverage length and space range of different gauges is apparent, which provides a physical and technological basis for railway system differentiation and network fragmentation, which leads to the formation of eight railway geo-systems. Due to different modes for railway transport management in different geographical locations, the geographical pattern and geographical relationship of four transport organizations are formed. What especially important is the emergence of "1435 gauge space" and "1520 gauge space", as well as the railway geo-space confrontation between them, on the Eurasian continent. Besides, we also find that the railway geo-system of Eurasia is mainly affected by the technology dissemination, path dependence, geopolitics, national defense and the colonial expansion of military latitude, and on this basis, five geo-modes of railway gauge propagation are formed. [ABSTRACT FROM AUTHOR]

When treating drinking water using UV/H2O2 advanced oxidation, the H2O2 residual is usually quenched to allow for downstream chlorine stability. In some utilities, monochloramine (NH2Cl) is used for secondary disinfection, and H2O2 may not need to be quenched because NH2Cl and H2O2 can coexist for some time. However, when ammonia and chlorine are applied to form NH2Cl in the H2O2 -containing water, H2O2 will compete with ammonia to react with the applied chlorine, compromising the NH2Cl formation efficiency. This research combined theory and experiments to evaluate NH2Cl formation efficiency in the presence of H2O2 in Lake Ontario water and, after NH2Cl formation, its subsequent decay at different temperatures and pH. The results demonstrated that at many typical temperatures and pH, the presence of H2O2 does not significantly impair the formation of NH2Cl. Furthermore, while H2O2 accelerates NH2Cl decay, the results suggest that under specific conditions, such as short to medium residence times (e.g., less than 48 h), it may be possible for NH2Cl to coexist with as much as 5 mg/L H2O2 without compromising secondary disinfection. [ABSTRACT FROM AUTHOR]

Objective: This study aims to assess the effectiveness of endoscopic tympanoplasty without mastoidectomy in the management of active mucosal chronic otitis media (COM) patients with mastoid and tympanic antrum lesions.Methods: It is a prospective controlled study where 42 patients with active mucosal COM with mastoid and tympanic antrum lesions or normal aeration were recruited from the outpatient clinic of the otology department, Eye Ear Nose and Throat Hospital of Fudan University. All patients underwent endoscopic tympanoplasty without mastoidectomy by using the underlay technique with tragal cartilage graft with one side-perichondrium. The follow-up period was at least 3 months and results were evaluated in terms of graft uptake, ear dryness and hearing improvement.Results: Statistics showed no significant difference in graft uptake between the mastoid and tympanic antrum lesions group (90.5%) and the normal aeration group (95.2%). There was no significant difference in ear dryness between the mastoid and tympanic antrum lesions group (95.2%) and the normal aeration group (100%). Hearing improvement was comparable in the 2 groups.Conclusion: Regardless of the occurrence of soft density shadows in temporal bone showed by high-resolution computerized tomography in the mastoid and tympanic antrum, mastoidectomy is an unnecessary procedure for dealing with active mucosal COM without cholesteatoma. Therefore, this study shows that endoscopic tympanoplasty without mastoidectomy may be applied to active mucosal COM without cholesteatoma. [ABSTRACT FROM AUTHOR]

In concert with developments in global trade and energy resource transportation, there has been a marked increase in reliance on overseas shipping. Unimpeded marine transportation has therefore become a key issue which influences national maritime interests including the security of trade and energy resources. A strategic shipping pivot thus performs a vital controlling function for global shipping networks. In this study strategic shipping pivots are defined and subdivided into sea hubs, channels and areas. We then develop a model to identify strategic shipping pivots on a global scale. The results show that, depending on differences in location, function, and type, the concept of strategic shipping pivot permits the identification of both spatial and structural differentiation with respect to strategic hubs, corridors, and seas. Now 44 strategic hubs have formed across the globe. These hubs have become the control centers of local shipping network organization. At the same time, seven strategic corridors containing most shipping routes and transportation capacity connect important sea areas, and permit a high-degree of control over the transport of strategic materials. The strategic seas, the Caribbean, the Mediterranean, Southeast Asia, and the Pacific provide vital import and export pathways, so that the formation of strategic shipping pivots is mainly influenced by factors such as physical geographical conditions, the spatial distribution of socio-economic activities, business organization, technical progress, geopolitical patterns and geopolitical disputes. Physical geographical conditions provide the potential foundations for strategic shipping pivots, while the spatial distribution of socio-economic activities and communications determine the strategic value of these points. Finally, business organization, technical progress, and geopolitical disputes all function to strengthen the strategic mechanisms and the mutagenicity of strategic shipping pivots. [ABSTRACT FROM AUTHOR]

Coal is a basic resource and its use guarantees the development of national economies and human society. Thus, coal transportation is an important part of China's overall transportation system. In this system, ports are the vital transit nodes. This study considered coastal ports in China and analysed the evolution of coal transportation from 1973 to 2013. We focused on the spatial pattern of coal loading and unloading, and summarized the main characteristics and development of the processes. Then, we examined the volumes of coal transported and regional changes in these amounts using mathematical models and indicators. Finally, we analysed the specialized function and spatial differentiation of the ports involved in coal transportation to reveal their spatial relationship and temporal evolution. We found that the spatial pattern of coal transportation changed from "south input and north output" to "all input and north output". However, the prominent ports used for coal unloading are still concentrated in areas south of the Yangtze River. Coal loading is concentrated on the west bank of Bohai Bay. In addition, some ports around Bohai Bay, such as Dandong, Dalian, Yantai, and Qingdao, changed from traditional coal loading ports to unloading ports. This study further developed the theory of transport geography, and improved our understanding of China's coal transportation system. [ABSTRACT FROM AUTHOR]

The 'High-Level Forum of the Development of China's Human Geography Under the Background of Change' was held in Beijing on January 22-23, 2016. More than 30 professors attended this forum. At this conference, they discussed the major progress made towards developing China's human geography, as well as the existing problems, limiting factors, opportunities, international collaborations, emerging directions, and prospects in the development of this discipline. In recent years human geography has boomed, generating many important opportunities for its development. Establishing an academic community for joint research on major research issues and collaborative innovation is a promising and important route to take. We should embrace both domestic and international characteristics, to promote China's human geography onto the world stage. Meanwhile, the cultivation of various scholarly talents is also of great value to enrich and advance the discipline. [ABSTRACT FROM AUTHOR]

As an important branch of human geography, transportation geography has experienced three periods of evolution: foundation, systematization, and rapid development of the discipline. It has gradually become a relatively mature discipline. During the period 1930-1980, the development of transportation geography consisted mainly of the publication of theoretical texts. During 1980-2000, it gradually became a systematic discipline. Since the start of the 21st century, transportation geography has focused mainly on exploring the impacts of transportation on socio-economic development. Currently, studies on transportation geography have led to significant developments in a number of areas, including transportation theory, facility distribution and planning, transportation flows and network analysis, evaluation of transport modes, transportation planning, and simulation and assessment of urban transportation. Such studies have also enriched human geography research, provided a wider geographical overview and elucidated the development mechanism of transportation, as well as helped to understand the impacts of transport development on socio-economic systems. Some findings obtained by geographers have been widely used in transportation geography and related fields, including the four basic laws of transportation generation, the hub-spoke mode of transport organization, the subordinating and guiding functions of transportation on socio-economic development, regional transport dominance measures, accessibility measures, and spatial organization of port systems. [ABSTRACT FROM AUTHOR]

Over the past two decades, numerous ports located in China have participated in port integration strategies, thus influencing the entire port system. The current research is initiated in order to examine the nature of port integration in China, including associated temporal pathways, spatial patterns and dynamics. Results indicate that port integration in China has been characterized by a significant increase at the turn of the 21st century, comprising thirteen distinguishable pathways typified by differing dynamics, particularly between the northern and southern ports. Pathways were found to include 44 seaports and river ports, chiefly concentrated in the Bohai Rim, Yangtze (Changjiang) River Delta, Beibu Gulf and the southeastern Fujian, thus representing significant spatial regions. Categorically larger seaports have become the primary beneficiaries of port integration. Integration cases were divided into four categories based upon quantified dynamic magnitude including the government-driven mode, market-driven mode, government/market-driven mode and strategic alliance, and into five further categories based upon spatial extent including port internal integration, jurisdictional port integration, port integration across neighbor region, regional port integration and hub-feeder port integration. Results suggest that several factors have effectively driven port integration in China, including legislative tools and spatial planning, optimization of shoreline resources and port functionality, and port competition with the same hinterland. [ABSTRACT FROM AUTHOR]

Before the emergence of modern modes of transport, the traditional road infrastructure was the major historical means of carrying out nationwide socio-economic exchange. However, the history of transport infrastructure has received little attention from researchers. Given this background, the work reported here examined the long-term development of transport networks in China. The national road network was selected for study and the 3500 years from 1600 BC to 1900 AD was chosen as the study period. Indicators were designed for the maturity level of road networks and an accessibility model was developed for the paths of the shortest distance. The evolution of the road network in China since the Shang Dynasty (1600 BC) was described and its major features were summarized to reveal long-term regularities. The maturity level of the road network and its accessibility was assessed and regions with good and poor networks were identified. The relationship between China's natural, social, and economic systems and the road network were discussed. Our analysis shows that the road network in China has a number of long-term regularities. The continuously expanding road network follows a path of inland expansion especially towards the border areas. However, its coverage and accessibility are characterized by a core-peripheral configuration, which has close relationships with, not only the natural conditions, but also national defense and warfare. The centralization of national power, national land governance, postal transport, the transport of specialized cargos, and international trade are also related to the development of the road network. This research draws attention to the evolving regularities of transport networks. [ABSTRACT FROM AUTHOR]

Spatial models of port system evolution often depict linearly the emergence of hierarchy through successive concentration phases of originally scattered ports. The Chinese case provides a fertile ground for complementing existing works by a long-term perspective, given the early importance of river ports and seaports and the development irregularities caused by periods of closure and openness over time and across such a large land mass. In both qualitative and quantitative ways, this paper describes and analyses the changing spatial pattern of China's port system since the first unified empire (221 bc). Main results underline a certain stability of the port system with regard to the location of main sea-river gateways, notwithstanding important regional shifts from one period to the other. [ABSTRACT FROM AUTHOR]

The aim of this paper is to study the spatialtemporal differentiation of industrial eco-efficiency in China. Using methods based on the data envelopment analysis (DEA) model and exploratory spatial data analysis (ESDA) and data from 1985, 1995, 2005, and 2008 of 30 provinces in China, the spatial-temporal pattern changes in industrial eco-efficiency are discussed. The results show that: first, the patterns of industrial eco-efficiency are dominated by clustering of relatively low efficiency provinces; second, spatial relationships between the industrial eco-efficiencies of different provinces changed slightly throughout the period and the provinces persistently exhibit spatial concentration of relatively low industrial eco-efficiency; finally, there is an obvious trend in the polarization of industrial eco-efficiency, i.e., the higher level spatial units are concentrated in eastern China, and the lower level spatial units are mainly in western and central China. [ABSTRACT FROM AUTHOR]

Scientific development is an invaluable asset to a country. Policies and development modes should be carried out based on scientific findings not only in industry, but also in transportation infrastructure construction. Building an integrated transportation system, which is in line with the national requirements of China and supports sustainable socio-economic development, is a key strategic issue related to building a moderately prosperous society and achieving realistic goals of a medium-level developed country. Based on a systematic review of the advances in China's transportation infrastructure over the last 60 years, this paper explores the main drivers of transportation development, including national policy, transportation structure, investment efficiency, and technological innovation. Analysis shows that China's comprehensive transportation infrastructure construction since 1949 can be divided into five stages initiated by these drivers, which correspond to four transition modes: policy transition, structural transition, efficiency transition, and technology transition. The transition path of China's transportation development shows that the dominant factors have changed, and the interval for each transition has shortened. With the implementation of the '12th Five-Year Plan', China's transportation infrastructure construction is showing some new characteristics and facing a new development transition. Finally, this paper analyzes the trends in transportation development in China and concludes that technological innovation will be the main driving force to increase the transportation supply and service area in the future. [ABSTRACT FROM AUTHOR]

The growth of peripheral ports to dominant hubs has been well documented in North America and Europe, and has led to the elaboration of several theoretical models. However, although changes in containerization growth have been taking place in the South and East Asia in recent years, particularly in China, only a few studies have focused on this region. The Pearl (Zhujiang) River Delta (PRD) has a typical port system with hub and peripheral ports, and provides an excellent case for studying the Peripheral Challenge. This paper introduces the theoretical evidence of the Hayuth model and analyzes the evolution of the container port system in the PRD with five phases: 1) phase I: preconditions for change and phase II: initial container port development in the 1970s and early 1980s; 2) phase III: diffusion, consolidation, and port concentration in the middle and late 1980s; 3) phase IV: the load center in the 1990s; and (4) phase V: the Peripheral Challenge since the late 1990s. The results illustrate that the Shenzhen port presents mounting challenges to the Hong Kong port, descending from a transshipment hub of China to a regional load center of Southeast China. Furthermore, this paper explores five points that have led to the evolution of the port system in the PRD: 1) competition in the regional port systems; 2) different interested parties; 3) shift of investment strategies of international terminal operators; 4) integration of shipping networks and reorganization of carriers; and 5) cost-based competition. [ABSTRACT FROM AUTHOR]

Transport infrastructure plays an important role in shaping the configuration of spatial socio-economic structures and influences regional accessibility. This paper defines transport dominance from three aspects: quality, quantity, and advantage, measured by density, proximity, and accessibility indices. County is the basic unit for analysis. The results reveal: (1) Transport dominance statistically follows a partial normal distribution. A very few counties, 1.4% of the total, have extremely high transport dominance which strongly supports the socio-economic development in these areas. In contrast, one eighth of all counties have poor transport dominance which impedes local socio-economic development to some extent. The remaining areas, about 70% of the counties, have median transport dominance. (2) Transport dominance is spatially unevenly distributed, with values decreasing gradually from the coastal area to the inland area. Areas in the first-highest level of transport dominance are mainly concentrated in the Yangtze River Delta, the Greater Beijing area, and the Pearl River Delta. Areas in the second-highest level are focused in Chengdu, Chongqing, and Wuhan metropolitan areas. Provincial capitals and a few other counties belong to the third-highest level. [ABSTRACT FROM AUTHOR]

Since the new century, countries in Africa have started a new round of rail network planning and construction which brings the completed different features together with the spatial organization of the railway network during the colonial period. Along with the strategic layout of "going out" with China's railways, the organizational structure of the African railway network will make a tremendous change for the construction market, network organization, and gauge structure of the African railways. Based on the literature reviews, we analyzed and forecasted the evolution of railway network in Africa and discussed the spatial differentiation of the future construction market of the railways from the view of country and enterprise. The results show that the development of the African railway networks will experience three stages: 1850–1960, 1960–2010 and 2010–2050, and that the organization pattern of the African railway network has evolved from the "Hinterland-Port" model to the "Continental Integration" model. The development of railway technical standards tends to be integrated, the gauge type is changed from complicated to single, the gauge distribution is changed from broken to uniform. The contractor countries of the railway changed from English-French dominated to China dominated. The application of railway technical standards is influenced by technology dependence and path dependence and is mainly reflected in the two characteristics of "Chinese standard implantation" and "local standard retention". The contractor enterprises of railway have a monopoly on the market of a country, CCECC and CRCC are leading, and the contractor enterprises are spatially characterized by four spatial distribution modes: single, continuous, jumping and comprehensive. [ABSTRACT FROM AUTHOR]

Urban integration, a new concept in urban and regional research, is an inevitable outcome of urban development. Based on accessibility analysis, this study uses urban and road network data to identify urban pairs in Northeast China which meet the distance threshold for urban integration and establishes an index system to evaluate the development potential. The research shows that in Northeast China, the results for urban integration are similar to those for the present urban structure in China, that is, a spatial pattern with provincial capital cities at the core and an urban belt as the axis. According to the evaluation, areas with potential for urban integration may be classified into four categories, namely, dominant areas, key areas, ordinary areas, and alternative areas. The candidate and potential areas for urban integration tend to be concentrated near a provincial capital city or a regional development zone. The results show that the development potential for urban integration varies greatly among the different urban pairs and the main constraining factors are different for each location. Among the constraining factors, the commuting time, costs, and economic conditions for the citizens are the most important. [ABSTRACT FROM AUTHOR]

Special functional areas and poor areas tend to spatially overlap, and poverty is a common feature of both. Special poor areas, taken as a kind of "policy space," have attracted the interest of researchers and policymakers around the world. This study proposes a basic concept of special poor areas and uses this concept to develop a method to identify them. Poor counties in China are taken as the basic research unit and overlaps in spatial attributes including old revolutionary bases, borders, ecological degradation, and ethnic minorities, are used to identify special poor areas. The authors then analyze their basic quantitative structure and pattern of distribution to determine the geographical bases' formation and development. The results show that 304 counties in China, covering a vast territory of 12 contiguous areas that contain a small population, are lagging behind the rest of the country. These areas are characterized by rich energy and resource endowments, important ecological functions, special historical status, and concentrated poverty. They are considered "special poor" for geographical reasons such as a relatively harsh natural geographical environment, remote location, deteriorating ecological environment, and an inadequate infrastructure network and public service system. Some areas suffer from underdevelopment and even lack the infrastructure for basic living. In order to prevent further deterioration of the economic, social, and ecological environments in these areas, targeted policies need to be implemented. [ABSTRACT FROM AUTHOR]

Access to sterile personal protective equipment, in particular for filtered face respirators is critical in the current pandemic for front line healthcare workers. Extended use may be required during supply shortages or due to economic considerations. UVC sterilization can be a cost‐effective technique capable of high throughput. The suitability of various N95 respirator designs for UV mediated reuse were evaluated based on the materials utilized. (Background image: with permission from Prescientx. Virus image: Sophia Lilge. Further details can be found in the article by Lothar Lilge, Angelica Manalac, Madrigal Weersink, Fynn Schwiegelshohn, Tanner Young‐Schultz, Abdallatif Satti Abdalrhman, Chengjin Wang, Aldrich Ngan, Frank X. Gu, Vaughn Betz, Ron Hofmann (e202000232). [ABSTRACT FROM AUTHOR]

Cruise tourism is an obviously global industry in different dimensions. From a geographical perspective, cruise ships are mobile and capable of being repositioned at a company's notice, which forms the inherent basis for its global spatial layout. As a branch of the cruise industry, the world cruise is clearly globalizing in geographical space by offering long itinerary, even round-the-world trips, for everyone. Using the schedule data from 2018 to 2019, this paper analyzes the spatial characteristics of the itinerary and port organization of Cunard, a world cruise company. We find that the itinerary distribution and port organization of Cunard are both globalization and regionalization, and the latter is the core and main component of the former. Under the influence of the COVID-19 epidemic, the global mobility of cruises has ground to a halt, while local mobility offers the possibility of its resumption as soon as possible. Turning to the regional voyage with the shorter and simple itinerary is feasible for Cunard and other world cruises, which is conducive to the realization of the resuming voyage as soon as possible. Moreover, strict boarding and safety onboard are essential. [ABSTRACT FROM AUTHOR]