Speed behaviour and mental workload of small-spacing expressway interchanges based on field driving test.

Many small-spacing interchanges (SSI) appear with the improvement of the expressway network. To investigate the speed and mental workload characteristics in the SSI and acquire the mechanism of the influence of speed on the drivers' workload, 37 participants were recruited to perform a field driving test. Each driver performed four driving conditions (i.e. ramp-mainline, mainline-ramp, mainline driving, and auxiliary lane driving). The speed and drivers' electrocardiogram (ECG) data were collected using SpeedBox speed acquisition equipment and PhysioLAB physiological instrument. The heart rate increase (HRI) index was used to analyse the drivers' mental workload regularity. The relationship model between speed and HRI was developed to examine the impact of speed on HRI. The results show that the speed variation in the SSI displayed two patterns: 'decrease - increase and continuous decrease.' The drivers' HRI variation presented four patterns: 'convex curve, continuously increasing, continuously decreasing and concave curve'. SSI's influenced area length is given based on the speed and HRI variation regularity. HRI is significantly higher when driving in the ramp-mainline condition in the SSI than when driving in other conditions, indicating that drivers are more nervous when merging with the mainline traffic. HRI increases significantly in the first 50% of the weaving area in four driving conditions, indicating that vehicle weaving greatly influences the drivers' mental workload. A positive correlation exists between vehicle speed and drivers' HRI without interference from other vehicles and road alignment.

The shorter spacing of the interchange will result in a more difficult driving task for the drivers. This study shows that drivers have the highest mental workload in ramp-mainline driving condition at small-spacing interchanges. The first half of the weaving area is the area where drivers' mental workload increases significantly, and is a high-risk section for small-spacing interchanges. This study can provide a reference for the revision of the allowable minimum interchange spacing in the corresponding specification, and the calibration of the simulation test parameters for similar scenarios.

Research on Vehicle Trajectory Deviation Characteristics on Freeways Using Natural Driving Trajectory Data.

Lateral driving behavior analysis is the foundation of freeway cross-section design and the focus of road safety research. However, the factors that influence vehicle lateral driving behavior have not been clearly explained. The dataset of the natural driving trajectory of freeways is used in this study to analyze vehicle lateral driving behavior and trajectory characteristics. As vehicle trajectory characteristic indicators, parameters such as preferred trajectory deviation and standard deviation are extracted. The effects of lane position, speed, road safety facilities, and vehicle types on freeway trajectory behavior are investigated. The results show that lane width and lane position significantly impact vehicle trajectory distribution. As driving speed increases, the lateral distance between vehicles in the inner lane and the guardrail tends to increase. In contrast, vehicles in the outside lane will stay away from the road edge line, and vehicles in the middle lane will stay away from the right lane dividing line when the speed increases. Statistical analysis shows that the preferred trajectory distribution of the same vehicle type in different lane positions is significantly different among groups (Cohen's d > 0.7). In the same lane, the lateral position characteristics of the center of mass of different vehicle types are basically the same (Cohen's d < 0.35). This work aims to explain what variables cause trajectory deviation behaviors and how to design traffic safety facilities (guardrail and shoulder) and lane width to accommodate various vehicle types and design speeds.

Co-assembled perylene/graphene oxide photosensitive heterobilayer for efficient neuromorphics.

Neuromorphic electronics, which use artificial photosensitive synapses, can emulate biological nervous systems with in-memory sensing and computing abilities. Benefiting from multiple intra/interactions and strong light-matter coupling, two-dimensional heterostructures are promising synaptic materials for photonic synapses. Two primary strategies, including chemical vapor deposition and physical stacking, have been developed for layered heterostructures, but large-scale growth control over wet-chemical synthesis with comprehensive efficiency remains elusive. Here we demonstrate an interfacial coassembly heterobilayer films from perylene and graphene oxide (GO) precursors, which are spontaneously formed at the interface, with uniform bilayer structure of single-crystal perylene and well-stacked GO over centimeters in size. The planar heterostructure device exhibits an ultrahigh specific detectivity of 3.1 × 1013 Jones and ultralow energy consumption of 10-9 W as well as broadband photoperception from 365 to 1550 nm. Moreover, the device shows outstanding photonic synaptic behaviors with a paired-pulse facilitation (PPF) index of 214% in neuroplasticity, the heterosynapse array has the capability of information reinforcement learning and recognition.

Analysis on Risk Characteristics of Traffic Accidents in Small-Spacing Expressway Interchange.

Many small-spacing interchanges (SSI) appear when the density of the expressway interchanges increases. However, the characteristics of traffic accidents in SSI have not been explained clearly. Therefore, this paper systematically takes the G3001 expressway in Xi'an as the research object to explore the accident characteristics of SSI. Firstly, the expressway is divided into four sections. Furthermore, their safety can be evaluated by the number of accidents per unit distance of 100 million vehicles (NAP). Subsequently, eight indexes, such as mean spacing distance (MSD), are selected to explain the cause affecting expressway safety by developing the least square support vector machine (LSSVM). Secondly, the difference between SSI and normal-spacing interchanges (NSI) is clarified by statistical analysis. Finally, LSSVM, random forest, and logistic regression models are built using 12 indicators, such as the time spent exploring the causes of serious accidents. The results show that the inner ring NAP in Sections I and II with SSI is 27.2 and 33.7, higher than in other sections. The density, annual average daily traffic, and MSD adversely affect expressway traffic safety. The road condition mainly influences the serious traffic accidents in the SSI. This study can provide the theoretical basis for traffic management and accident prevention in the SSI of the expressway.

Shoot-soil ecological stoichiometry of alfalfa under nitrogen and phosphorus fertilization in the Loess Plateau.

Plants and soil interactions greatly affect ecosystems processes and properties. Ecological stoichiometry is an effective means to explore the C, N, P correlation between plants and soil and the relationship between plant growth and nutrient supply. Serious soil erosion on China's Loess Plateau has further barrenness the soil. Fertilization solves the problem of ecosystem degradation by improving soil fertility and regulating the ecological stoichiometric between soil and plants. No fertilization (CK), nitrogen fertilization (N), phosphorus fertilization (P) and N and P combined fertilization (NP) treatments were set in an alfalfa grassland. Organic carbon (C), nitrogen (N) and phosphorus (P) nutrients and their stoichiometry were measured in shoot and soil. P and NP fertilization increased shoot C concentration (3.12%, 0.91%), and all fertilization decreased shoot N concentration (6.96%). The variation of shoot C and N concentrations resulted in a greater increase in shoot C:N under the fertilization treatment than that under CK (8.24%). Most fertilization treatments increased shoot P concentration (4.63%) at each cut, which induced a decrease of shoot C:P. Shoot N:P of most treatments were greater than 23, but it was lower under N and NP fertilization than that under CK. Fertilization only increased soil C in 2014, but had no effect on soil N. Soil P content was significantly higher under P fertilization in 2014 (34.53%), and all fertilization in the second cut of 2015 (124.32%). Shoot and soil C:P and N:P having the opposite changes to shoot and soil P, respectively. Our results suggest that the change of P after fertilization largely drove the changes of stoichiometric. The growth of alfalfa in the Loess Plateau was severely restricted by P. It is an effective method to increase the biomass of alfalfa by increasing the addition of N or NP fertilizer to alleviate P limitation.

Multimode Visualization of Electronic Skin from Bioinspired Colorimetric Sensor.

Bioskins possess a great ability to detect and deliver external mechanical or temperature stimuli into identifiable signals such as color changes. However, the integration of visualization with simultaneous detection of multiple complex external stimuli in a single biosensor device remains a challenge. Here we propose an all-solution-processed bioinspired stretchable electronic skin with interactive color changes and four-mode sensing properties. The fabricated biosensor demonstrates sensitive responses to various stimuli including pressure, strain, voltage, and temperature. Sensing visualization is realized by color changes of the e-skin from brown to green and finally bright yellow as a response to intensified external stimuli, suggesting great application potential in military defense, healthcare monitoring, and smart bionic skin.

Wearable and washable light/thermal emitting textiles.

Electronic textiles (e-textiles) typically comprise fabric substrates with electronic components capable of heating, sensing, lighting and data storage. In this work, we rationally designed and fabricated anisotropic light/thermal emitting e-textiles with great mechanical stability based on a sandwich-structured tri-electrode device. By coating silver nanowire network/thermal insulation bilayer on fabrics, an anisotropic thermal emitter can be realized for smart heat management. By further covering the emissive film and the top electrode on the bilayer, light emitters with desirable patterns and colors are extracted from the top surface via an alternative current derived electroluminescence. Both the light and thermal emitting functions can be operated simultaneously or separately. Particularly, our textiles exhibit reliable heating and lighting performance in water, revealing excellent waterproof feature and washing stability.

Solution-Processable 2D Polymer/Graphene Oxide Heterostructure for Intrinsic Low-Current Memory Device.

Suppressing the operating current in resistive memory devices is an effective strategy to minimize their power consumption. Herein, we present an intrinsic low-current memory based on two-dimensional (2D) hybrid heterostructures consisting of partly reduced graphene oxide (p-rGO) and conjugated microporous polymer (CMP) with the merits of being solution-processed, large-scale, and well patterned. The device with the heterostructure of p-rGO/CMP sandwiched between highly reduced graphene oxide (h-rGO) and aluminum electrodes exhibited rewritable and nonvolatile memory behavior with an ultralow operating current (∼1 µA) and efficient power consumption (∼2.9 µW). Moreover, the on/off current ratio is over 103, and the retention time is up to 8 × 103 s, indicating the low misreading rate and high stability of data storage. So far, the value of power is about 10 times lower than those of the previous GO-based memories. The bilayer architecture provides a promising approach to construct intrinsic low-power resistive memory devices.

Transcriptome analysis reveals potential genes involved in flower pigmentation in a red-flowered mutant of white clover (Trifolium repens L.).

White clover (Trifolium repens L.) has been cultivated for ornamental use because of its flowers, leaf marks and creeping habit. Although a mutation in flower color is very infrequent in this species, the red-flowered mutant of white clover was a novel germplasm for ornamental white clover breeding. The mechanism of flower pigmentation in white clover is still limited because of the rarity of mutation materials and the lack of genomic data. In this study, two cDNA libraries from red-flowered white clover mutant between sunlight-exposed plants and shade-treated plants, respectively, were used for transcriptome sequencing. A total of 157,964 unigenes with an average length of 728bp and a median length of 1346bp were isolated. A large number of differentially expressed genes (6282) that were potentially involved in multiple biological and metabolic pathways, including anthocyanin flavonoid biosynthetic pathway and flavonoid biosynthetic pathway, were obtained, 70 of which could be identified as putative homologues of color-related genes. Furthermore, eight key candidate genes (CHS, F3'H, F3'5'H, UFGT, FLS, LAR, ANS, and DFR) in flavonoid biological synthesis pathway were identified by quantitative real-time PCR (qRT-PCR). Mass sequence data obtained by RNA-Seq of white clover and its red-flowered mutant provided basic sequence information and a platform for future molecular biological research on the red flower trait.

Proteomic analysis of early salt stress responsive proteins in alfalfa roots and shoots.

BACKGROUND: Alfalfa (Medicago sativa) is the most extensively cultivated forage legume in the world, and salinity stress is the most problematic environmental factors limiting alfalfa production. To evaluate alfalfa tissue variations in response to salt stress, comparative physiological and proteomic analyses were made of salt responses in the roots and shoots of the alfalfa. METHOD: A two-dimensional gel electrophoresis (2-DE)-based proteomic technique was employed to identify the differentially abundant proteins (DAPs) from salt-treated alfalfa roots and shoots of the salt tolerance cultivars Zhongmu No 1 cultivar, which was subjected to a range of salt stress concentrations for 9 days. In parallel, REL, MAD and H2O2 contents, and the activities of antioxidant enzymes of shoots and roots were determinand. RESULT: Twenty-seven spots in the shoots and 36 spots in the roots that exhibited showed significant abundance variations were identified by MALDI-TOF-TOF MS. These DAPs are mainly involved in the biological processes of photosynthesis, stress and defense, carbohydrate and energy metabolism, second metabolism, protein metabolism, transcriptional regulation, cell wall and cytoskeleton metabolism, ion transpor, signal transduction. In parallel, physiological data were correlated well with our proteomic results. It is worth emphasizing that some novel salt-responsive proteins were identified, such as CP12, pathogenesis-related protein 2, harvest-induced protein, isoliquiritigenin 2'-O-methyltransferase. qRT-PCR was used to study the gene expression levels of the four above-mentioned proteins; four patterns are consistent with those of induced protein. CONCLUSION: The primary mechanisms underlying the ability of alfalfa seedlings to tolerate salt stress were photosynthesis, detoxifying and antioxidant, secondary metabolism, and ion transport. And it also suggests that the different tissues responded to salt-stress in different ways.

[Advances in haustoria function of plants obligate parasite-A review].

Haustoria, one of the fundamental characteristics of obligate parasite, is a micro-branch produced by biotrophic fungi and oomycetes, which is composed of haustorial body, extrahaustorial matrix and extrahaustorial membrane. It is an abnormal structure that can invade the host cell interaction with the plant. Haustoria is not only the key factor of biotrophic fungi carrying on the living specimen nutrition way but also represents significant roles in the nutrition biosynthesis and inhibiting the defense reaction of host. The deeper understanding of haustoria will favor us acquaint obligate parasite enormously, so that we can control the corresponding diseases better. This paper summarized the function on nutrition and pathogenicity of haustoria, and the problems and the research trend in this area were discussed.