Direct Characteristics Research Articles

Electronic and adsorption characteristics of hydrogen cyanide (HCN) and isocyanide (HNC) on intrinsic and doped phosphorene

Density functional theory calculations are performed to investigate the electronic properties of the phosphorene that is substituted with the non-metals in different patterns and concentrations and to study the adsorption of the toxic gases, hydrogen cyanide (HCN) and isocyanides (HNC), on the intrinsic and nitrogen-doped phosphorene adsorbents. It has been established previously that the number of valence electrons in the dopant atoms considerably affects the electronic characteristics of phosphorene. Doping with B, S, Si, and other non-metals has resulted in drastic changes in the direct bandgap characteristics of the semiconductor, resulting in the conversion of the semiconductor into an indirect bandgap material (boron-doped) or metallic (Si/S doped). Of all the doped surfaces, only nitrogen-doped phosphorene shows a direct bandgap. Therefore, adsorption studies are conducted to investigate the sensitivity of the toxic gases hydrogen cyanide (HCN) and isocyanide (HNC) on intrinsic and nitrogen-doped adsorbents. The adsorption results are compared to those on graphene and doped graphene surfaces. Pure phosphorene is a good candidate for the moderate adsorption of HCN and HNC due to its low adsorption energy and charge transfer. We have also found that intrinsic phosphorene is a better adsorbent for these gases than intrinsic graphene and doped graphene. In addition, N-doped phosphorene shows moderate reactivity toward HCN and HNC gases, suggesting it may be used as a metal-free catalyst for the adsorption of these adsorbates. The 2p orbitals on the nitrogen of HCN are found to play a significant role in the strong physisorption.

EIS equivalent circuit modeling of direct ammoniafuel cell (DAFC) and mass transfer characteristics for anode diffusion layers with different hydrophobicity

EIS equivalent circuit modeling of direct ammoniafuel cell (DAFC) and mass transfer characteristics for anode diffusion layers with different hydrophobicity

Dimension synthesis of linkage mechanism with approximate poses and velocity constraints

This paper mainly addresses the problem of dimension synthesis for planar open chain two-rod (2R) mechanisms with velocity constraints and position-pose information in agricultural transplanting mechanism (TM). The method proposed in this study extends the dimension synthesis problem of planar 2R mechanisms, which takes position-pose into account, to the dimension synthesis considering both position-pose information and velocity information (PPIAVA) at certain pose points in the field of TM. The geometric constraints of the open chain 2R mechanism are extracted from the prerequisite conditions obtained by a series of given position-pose points and velocity constraints at some pose points to solve the dimension synthesis problem of the planar 2R mechanism. First, the Taylor formula is used to connect the characteristic of the derivative value at a certain point as coefficient with PPIAVA at a certain point. The mathematical model of position-pose and velocity is established by combining the relationship of rod length constraint and velocity direction characteristic. Secondly, the nonlinear equations established according to the position-pose information and velocity constraints are combined with the Lagrange equation and the extremum of the multivariate function to transform the appropriate objective function and then solved the equations. Finally, a transplanting mechanism is designed and tested by combining the solution results with the trajectory characteristics of the TM. The results show that this method is an effective synthesis method for smoothly solving the dimension synthesis problem of planar open chain 2R linkage mechanism with velocity constraints, which can extract geometric constraints from a given series of position-pose and velocity constraints at some poses.

The BeP2 monolayer exhibits ultra-high and highly anisotropic carrier mobility and 29.3% photovoltaic efficiency.

Two-dimensional materials with a combination of a moderate bandgap, highly anisotropic carrier mobility, and a planar structure are highly desirable for nanoelectronic devices. This study predicts a planar BeP2 monolayer with hexagonal symmetry that meets the aforementioned desirable criteria using the CALYPSO method and first-principles calculations. Calculations of electronic properties demonstrate that the hexagonal BeP2 monolayer is an intrinsic semiconductor with a direct band gap of approximately 0.94 eV and this direct bandgap characteristic is maintained under strain. The mobilities of hexagonal BeP2 are electron-dominated, reaching ∼105 cm2 V-1 s-1, which is two orders of magnitude higher than the mobility of holes. The high carrier mobility results from the small deformation potential constant, which arises from the unique decoupling behavior of electrons in the valence and conduction bands. Furthermore, our calculations reveal that the photovoltaic efficiency of hex-BeP2 is as high as 29.3%, which is comparable to those of well-known thin-film solar cell absorbers, thanks to its high visible light absorption coefficient of ∼105 cm-1 and its direct bandgap feature.

Most recent and emerging technologies for enhancing the nutritional characteristics of food, challenges and future directions: A Review

The rapid advancement of emerging technologies is transforming the food industry, especially in enhancing the nutritional qualities of food. These innovations have significant potential for tackling global nutritional deficiencies and promoting public health. Key technologies include precision fermentation, which enables the production of high-quality proteins and micronutrients while minimizing environmental impact. Additionally, gene editing techniques such as CRISPR allow for the development of crops with improved nutrient profiles and enhanced resistance to pests and diseases. Furthermore, advancements in nanotechnology enhance the fortification of foods with essential vitamins and minerals, improving their bioavailability and stability. Personalized nutrition, driven by big data and artificial intelligence, customizes dietary recommendations based on individual genetic profiles, optimizing nutrient intake and health outcomes. This review article overviews these cutting-edge technologies and their applications in creating a more nutritious and sustainable food system.

Research on floor failure characteristics of dip direction in non-pillar mining with automatically formed roadway above confined water

Research on floor failure characteristics of dip direction in non-pillar mining with automatically formed roadway above confined water

Study on Influencing Factors of Liquid Carbon Dioxide Blasting in Rock Cutting

Background:: At present, although some scholars have studied liquid carbon dioxide blasting, there are still some problems to be solved, such as the influencing factors of the liquid carbon dioxide blasting effect. Based on the project of Jiu’e railway, this paper studies the influencing factors of liquid carbon dioxide blasting in rock cutting. Objective:: The study aims to show the influence of different blasting hole depths and jet directions on the effect of liquid carbon dioxide blasting and fracture development. Methods:: Considering the influence of jet direction and different blasting hole depth on liquid carbon dioxide blasting in rock cutting, the fracture development law at different blasting hole depths is analyzed, the stress characteristics of jet direction and non-jet direction are discussed, and fracture development process is analyzed in detail from the viewpoint of energy. Moreover, related patents on liquid carbon dioxide blasting devices are also reviewed. The research on law of fracture development and optimal blasting hole depth is the highlight of this paper. Results:: The influence of different blasting hole depths, jet directions on effect of liquid carbon dioxide blasting and fracture development is analyzed, When the depth of blasting hole is 2.5 m, the fractures can extend to bench surface but cannot extend to the bottom of the excavation surface. When the hole depth is 5.0 m, the fractures cannot extend to the bench surface. The fractures can be extended to the bottom of the excavation face and the bench surface when the blasting hole depth is 4.0. Moreover, the liquid carbon dioxide blasting can effectively blast the rock cutting, and the optimal blasting hole depth is 4m. Conclusion:: Through the analysis results, considering the influencing factors of fracture number, fracture length and consumption of blasting energy, a blasting hole depth of 4m is considered the best option.

Research on the characteristics of wind speed, wind direction, and wind profile based on ERA5 reanalysis data

Research on the characteristics of wind speed, wind direction, and wind profile based on ERA5 reanalysis data

Unraveling the complex interplay between curved tunnels and drivers’ physiological responses: An HRV perspective

This study aims to unravel the complex interplay between curved tunnels and drivers’ physiological responses from an HRV (Heart Rate Variability) perspective.A group of 30 individuals with valid driver’s licenses was selected, and their HRV was monitored while driving through four curved tunnels in Yunnan Province, China. HRV indicators such as RMSSD (Root Mean Square of Successive Differences), SDNN (Standard Deviation of Normal-to-Normal Intervals), LF (Low Frequency), and LF/HF (ratio of Low Frequency to High Frequency) were analyzed. The independent variables included tunnel radius, turn direction, and zone characteristics. The results demonstrated that the radius, turning, and zone of the curved tunnel significantly influenced drivers’ HRV. Specifically, as the tunnel radius decreased, the mean RMSSD and SDNN of drivers decreased, while the mean LF and LF/HF increased. In left turns, drivers had lower RMSSD and SDNN values but higher LF and LF/HF ratios compared to right turns. Additionally, drivers showed the highest mean RMSSD and SDNN in the entrance zone of the tunnel, followed by the middle zone, and the lowest in the exit zone. Conversely, the exit zone had the highest mean LF and LF/HF, followed by the middle zone, and the entrance zone had the lowest. These results indicate that the characteristics of the curved tunnel have a substantial impact on drivers’ physiological responses. A smaller tunnel radius leads to increased stress and cognitive load, as reflected by the decreased HRV metrics and increased sympathetic activity. Turning maneuvers, particularly left turns, result in asymmetry in autonomic responses, with lower RMSSD and SDNN and higher LF and LF/HF during left turns. The variations in HRV across different zones within the tunnel suggest that environmental cues play a role in sympathetic activation, with the exit zone showing the highest sympathetic activity. These findings offer significant insights into the relationship between tunnel conditions and drivers’ physiological responses, emphasizing the importance of considering these factors in road safety and human factors engineering. By comprehending how tunnel characteristics affect drivers’ autonomic nervous system responses, we can formulate strategies to enhance driver well-being and safety.

Precise Bottom-up Synthesis of Functional Nanowires and Nanosheets Based on 1D and Quasi-1D Van Der Waals Crystals

Anisotropy often leads to unexpected structures and properties in the solid state. In van der Waals (vdW) solids composed of 1D or quasi-1D (q-1D) building blocks, anisotropy in both intra- and inter-chain directions results in an abundance of crystalline packing motifs and drastically altered physical states. Among these, 1D/q-1D vdW solids that display topologically protected states, confined photonic modes, and direct band gap characteristics in few- to single-chains are highly sought after due to their tremendous potential as building blocks for next-generation quantum computing, spintronic, and telecommunication devices. Yet, access to such facet- and edge-specific physical states is still limited by the stochastic nature of micromechanical exfoliation. Here, we present two convergent efforts that address the growth of 1D and q-1D vdW crystals, which have closely related stoichiometric competing phases or exhibit rich polymorphism. First, I will describe the unique crystallization behavior of Bi4I4, a known topological insulator in bulk, in the presence of Au nanoparticle (NP) catalysts. Systematically varying Au NP diameters, Bi:I precursor ratios, and growth-deposition temperatures reveals that Au NPs generally act as nucleation sites for the vapor-solid (VS) growth of Bi4I4 nanowires. Strikingly, we discovered that post-synthesis analysis of 20 nm Au NPs, showing an equistochiometric 1:1 ratio of Bi to I within the Au NP, distinctly triggers the vapor-liquid-solid (VLS) growth of [001]-oriented quasi-2D nanosheets comprised of laterally-ordered [Bi4I4]n chains along the perpendicular [100] direction. Second, I will discuss how highly anisotropic and intrinsically strong covalent interactions along the long axis in 1D vdW crystals enable the uncatalyzed growth of record-long photonic nanowires (approximately 8 mm long with thicknesses ranging from 30 to 60 nm) via bottom-up vapor-phase routes. In both systems, we employ a series of structural and spectroscopic techniques to establish the structure, polytype, and physical properties of the well-defined nanowires and quasi-2D nanosheets that emerge from our synthetic routes.

Study on direct shear mechanical characteristics of grouted-filled jointed coal using discrete element method

Grouting is a widely used technique in underground engineering by enhancing mechanical properties of jointed rock mass. Understanding the shear characteristics of jointed coal mass after grouting reinforcement is crucial for optimizing grouting parameters and advancing grouting mechanism. This study proposed a grout-filled jointed coal (GJC) direct shear discrete element model (GJCS-DEM). The model consists of coal matrix, grout-filled layer, and coal-grout interface. Parallel bond model (PBM) was adopted on intact coal matrix and grout-filled layer, while smooth joint model (SJM) was utilized to model deform behavior of interface in this model. Then, microscopic parameters determination method for SJM in GJCS-DEM has also been introduced and all the parameters for PBM and SJM were calibrated. After that, the proposed approach was validated through the good agreement between strength and failure characteristics of numerical and experimental direct shear test results of specimens with different grouting materials. Finally, the validated GJCS-DEM was applied to investigate effect factors of shear mechanical propertied for GJC specimens. As the grout-filled layer height and joint sawtooth dig angle increases, both peak and residual strength increases, while the failure pattern varies. The work here can offer valuable insights for grouting efficiency improvement in engineering practices.

Industry Energy Dependence Characteristics Under Different Energy Consumption Accounting Scopes: A Comparison Between China and the U.S.

Energy plays a vital role in the sustainable development of the economy and society. The key measures for achieving sustainable development include optimizing the energy structure, improving energy efficiency, and reducing reliance on non-renewable energy sources. This study constructs a monetary energy consumption database for China that distinguishes between energy resources used as raw materials and those used as other intermediate inputs, based on China’s annual input–output table from 2001 to 2020. In this paper, the direct energy consumption and energy conservation potential of 33 industries in both China and the United States are compared under the following three energy consumption scopes: not excluding energy used as raw materials, excluding energy used as raw materials for the production of non-energy products, and excluding energy used as raw materials for the production of non-energy products or the production of energy products through non-combustion processes. This study also compares the direct energy dependence characteristics of these industries. The following conclusions are made: First, the energy consumption structure varies greatly under different scopes, of which the third scope is closest to the international standards. Second, China’s raw materials industries have made some progress in energy conservation, and their gap with those in the U.S. has started to narrow. Third, China’s high-tech industries still have potential for energy conservation and emission reduction.

Understanding and Quantifying the Benefit of Graded Aluminum Gallium Nitride Channel High-Electron Mobility Transistors.

Graded AlGaN channel High-Electron Mobility Transistor (HEMT) technology is emerging as a strong candidate for millimeter-wave applications, as superior efficiency and linearity performances can be achieved. In this paper, graded channel AlGaN/GaN HEMTs are investigated with the aim of further understanding the benefit of the graded AlGaN channel compared to more conventional GaN channel HEMTs. Our study employed a comprehensive simulation workflow including an extensive calibration of direct current (DC), S-parameter, large signal, and linearity characteristics at 30 GHz. Through device modeling and implementation of circuit-level simulation using Advanced Design System (ADS, 2023) software, both linearity and large signal performances could be mimicked remarkably. In agreement with previous studies, the results show that graded channel technology allows for a modified electron confinement leading to a 3D electron gas (3DEG). Consequently, the electric field peak inside of the channel is reduced without degrading the radio frequency (RF) performance, as the electron velocity is improved, thus offering a more linear transconductance and better linearity performances. As a result, for graded AlGaN channel HEMTs, a 6 dB output power back-off from peak power-added efficiency (PAE) is needed to achieve a carrier with a third-order intermodulation (C/IM3) ratio of 30 dBc against 9 dB for conventional AlGaN/GaN HEMTs with a lower associated PAE.

Mung bean protein enhances the expansion of corn starch during twin-screw extrusion.

This study examined the effects of the inclusion of mung bean protein (MBP) on the direct expansion characteristics of corn starch during twin-screw extrusion. Six blends of corn starch and MBP isolate (0%, 5%, 10%, 15%, 20%, and 25% w/w) were hydrated to three different moisture contents (MCs) (16%, 19%, and 21%w.b.). The blends were extruded using a twin-screw extruder at three screw speeds (SSs) (300, 400, and 500rpm). The resulting extrudates were evaluated for their water solubility index, water absorption index, expansion ratio (ER), true density, unit density, and porosity. As the protein content increased, the porosity of the extrudates increased. The ER of all extrudates ranged from 2.90 to 5.46, with the largest ER observed at an SS of 400rpm, an MC of 19%, and 25% MBP inclusion. The porosity of the extrudates ranged from 1.79% to 11.42%. SS and protein content had a significant impact (p<0.05) on the porosity and ER of the extrudate. PRACTICAL APPLICATION: This work provides valuable information for the industry on utilizing mung bean protein in direct expanded corn starch-based extruded snacks. The information could be useful in the development of high-protein extruded snacks and breakfast cereals.

Study on monotonic direct shear characteristics of geosynthetics–calcareous sand interface

The investigation of shear behavior at the geosynthetics–calcareous sand interface is crucial for the internal stability design of reinforced revetment structures. A series of large-scale monotonic direct shear tests was conducted to examine the interface shear characteristics of geotextile–calcareous sand (GT–CS), geogrid–calcareous sand (GG–CS), and unreinforced calcareous sand (URCS). The interface shear behavior was investigated by considering the effects of interface types, including URCS, GT–CS, and GG–CS interfaces, and normal stresses ranging from 25 to 100 kPa. The interface interaction mechanism for different interface types is disclosed. The results indicate that embedding geotextiles and geogrids into calcareous sand filler alters the interface dilatancy behaviour of calcareous sand, which is significantly affected by normal stress. The dilatancy curves of GT–CS and GG–CS interfaces predominantly exhibit contraction–dilation and contraction, whereas the dilatancy curves of the URCS interface primarily display contraction–dilation–contraction and contraction. The shear softening behavior of GT–CS and GG–CS interfaces is primarily influenced by interface interaction mechanisms at the hardening stage and post-peak softening stage. The use of geogrid/geotextile has a reinforcing effect on calcareous sand fillers, leading to an increase of 1.22–1.44 times in interface peak cohesion. This increase falls within the range observed for geosynthetics–siliceous sand and geosynthetics–soil.

Strategic Directions for Strengthening Sustainability of Forestry Workforce

Today in many countries and regions, forestry sector deals with a considerable shortage of forestry workers and faces the serious challenge of ensuring a qualified and sustainable workforce. Current global processes and structural changes, such as emigration from rural areas, aging of the population, unfavorable age structure of existing employees, negative demographic trends (migrations, decline in birth rate, negative natural increase, etc.), lack of interest in the so-called 3D (dirty, dangerous and demeaning) jobs, low cost of labor and others, significantly contribute to such an adverse situation. Additionally, forestry work, especially wood harvesting, represents a very risky, professionally highly demanding and physically extremely intensive activity, which is regularly classified as one of the most dangerous occupations with a high proportion of serious injuries, fatalities and occupational diseases. For these reasons, the forestry profession is considered unattractive, and the job of a forestry worker undesirable. All of this makes finding the people interested in these jobs very difficult, and the task of ensuring the necessary workforce for all regular activities in sustainable forest management becomes very hard. In this paper, based on the surveys carried out in the Federation of Bosnia and Herzegovina (FB&amp;amp;H), i.e. evaluation of forestry workforce sustainability factors, and on the study of available strategic documents, policies and case studies, strategic directions aimed at strengthening the sustainability of forestry workforce were elaborated. The sustainability factors were observed in three categories related to: a) stronger recruiting in forestry, b) more successful retention of forestry workers, and c) higher work commitment of forestry workers. Established rankings, together with other findings, were used to define four separate strategic directions: (1) Direct financial strategy, which emphasizes direct monetary payments to workers and is oriented towards labor productivity, (2) Indirect financial strategy, which focuses more on providing indirect material gains to workers and the quality of performed work, (3) Educational strategy, aimed at the education and training of workers, and (4) Technical-technological strategy, aimed at increasing the mechanization in forest operations thus reducing the demand for labor. The paper elaborates the basic starting points and main characteristics (priorities, measures and activities, stakeholders, responsible authorities, etc.) of each strategic direction considering the possibility and conditions of their implementation in national forestry sector. The objective of the paper is to raise the required awareness of the forestry workforce issues, its position and status, and also to provide foundations for enhancing the attractiveness of forestry work and improving the overall sustainability of the forestry workforce. The results of the study point out the critical issues and provide valuable insights that can help in formulating effective policies and strategies for the future.

Impact of oxygen vacancies on the structural, electronic, and optical properties of Cu&lt;i&gt;2&lt;/i&gt;O and nitrogen-doped Cu&lt;sub&gt;2&lt;/sub&gt;O for optoelectronic applications: a first-principles study

This study utilizes Density Functional Theory (DFT) within the Quantum ESPRESSO framework to explore the effects of oxygen vacancies and nitrogen doping on the electronic structure and optical properties of cuprous oxide (Cu2O). Pristine Cu2O, an intrinsic p-type semiconductor, typically exhibits a direct band gap. Introducing an oxygen vacancy in the absence of a dopant broadens the band structure, leading to both direct and indirect band gap characteristics. In contrast, nitrogen doping transforms the band gap into a direct one, significantly reducing it from 1.97 eV to 1.09 eV, which deviates from previous findings due to potential variations in the initial state of the Cu2O host crystal. Furthermore, spin-polarization effects indicate spin-dependent behaviour within the material. The study also examines the absorption properties of pristine, defective, and nitrogen-doped Cu2O systems using the complex dielectric function. The results show distinct absorption peaks and transitions, with nitrogen-doped Cu2O exhibiting strong absorption in the visible light range, underscoring its potential for solar cell applications.

Research on ecological compensation based on ecosystem service flow: A case study in Guangdong province, China

Ecological compensation (EC) is not only an essential tool for correcting the externalities of ecosystem services (ESs) and fostering sustainable development but also a crucial means to alleviate poverty and promote balanced development across regions. Based on the ecosystem service flow (ESF) theory, this article presents a universal framework for screening ESs in EC research, and employs multiple models and multisource data to measure the supply and demand of five ESs. Moreover, this study examined the transfer values of air-mediated ESs (AMESs) and water-mediated ESs (WMESs) using the field strength model and flow allocation method, respectively, due to their significant differences in flow direction, flow rate and attenuation characteristics. The results indicate that: (1) there is a significant disparity between the supply and demand of the five ESs in Guangdong, with the scope and extent of the mismatch varying among the different ESs. Generally, deficit areas are located in the central urban regions of the Pearl River Delta (PRD) cities and cities in eastern and western Guangdong. (2) The transfer values of all the surplus areas of the AMESs and WMESs to their corresponding deficit areas are 37.02 billion yuan and 37.43 billion yuan, respectively, accounting for 62.9% of the AMESs supply value in the study area and 2.5% of the output value of the WMESs in the surplus areas, indicating that a significant amount of the output value has been transferred to areas outside of the study area. (3) The total transfer in/out value between surplus and deficit areas is 71.83 billion yuan, and is economically acceptable for deficit areas. (4) Compared with the results of this study, some economically developed regions with high ecosystem service value (ESV) outputs in Guangdong have not been compensated, and the current EC standard is relatively low. We suggest that Guangdong pilot horizontal EC, explore various market-oriented trading systems, increase vertical EC standards and enrich EC methods. This study provides a reference for the quantification of ESFs with different transmission carriers and the improvement of EC policy in Guangdong.

Scientific Traditions as a Mechanism of Continuity of Psychological Cognition. Part 2. Problems, Approaches and Prospects for Research

The authors’ main attention is focused on current problems of studying continuity and scientific traditions in psychology. Special attention is paid to the characteristics of promising directions for studying the traditions of domestic psychological science: taking into account when studying the traditions of scientific developments on the generation of knowledge, primarily tacit; analysis of the role of individual personal variables, including ideological guidelines, cognitive attitudes, life values, features of the professional development of the researcher himself in the process of selection of knowledge acquiring the status of tradition; study of traditions as the foundations and distinctive features of scientific schools in psychology. A model for studying scientific traditions in psychology is proposed, based on ideas about three aspects of the existence of science (knowledge, social institution, cognitive activity) and different views on the understanding of the term “tradition” (according to E. Shatsky) — functional, objective and subjective. It is concluded that the preservation and development of scientific traditions is the responsibility of not only the scientific community as a whole, but also personally of each researcher involved in scientific creativity in the field of psychology.

The study on bond‐slip constitutive model of recycled concrete under different loading rates

AbstractIf recycled concrete is to be widely, reasonably, and safely applied in practical engineering, the study of bond‐slip performance between steel bars and concrete is crucial. In this paper, the central pull‐out test of recycled concrete under different loading rates was conducted. The characteristics of failure mode and crack directions of the specimens were observed and analyzed. The ultimate bond strength and slip displacement between rebar and concrete were analyzed. The effects of three parameters, namely concrete strength grades, replacement percentage of recycled coarse aggregate, and loading rates on the failure modes and bond‐slip mechanical properties of recycled concrete, were analyzed and summarized. The experimental results showed that there were significant differences in the influence trend and amplitude of the above three parameters on the ultimate bonding strength, slip amount, and slip curve. Based on the above experimental and theoretical analysis, a reasonable bond‐slip constitutive model was established in this paper and was in good agreement with the experimental results.