Carrier Type Research Articles

P-Type AgAuSe Quantum Dots.

Control over the carrier type of semiconductor quantum dots (QDs) is pivotal for their optoelectronic device applications, and it remains a nontrivial and challenging task. Herein, a facile doping strategy via K impurity exchange is proposed to convert the NIR n-type toxic heavy-metal-free AgAuSe (AAS) QDs to p-type. When the dopant reaches saturation at approximately 22.2%, the Femi level shifts down to near the valence band, with the p-type carrier characteristics confirmed through photoluminescence, X-ray photoelectron spectroscopy, and ultraviolet photoelectron spectroscopy analysis. First-principles calculations reveal that K impurities preferentially occupy interstitial positions and form complex defects when combined with the abundant cationic vacancy in AAS caused by the high mobility of Ag, thereby functioning as a shallow acceptor to enhance p-type conductivity. A p-n homojunction based on AAS QDs has been fabricated and served as the active layer in a photodiode device, which demonstrates an excellent room-temperature detectivity of up to 2.29 × 1013 Jones and an outstanding linear dynamic range of over 103 dB. This study provides guidance for future design of the p-n homojunction using the toxic-metal-free Ag-based QDs and further unleashes their potential in advanced optoelectronic device applications.

Research Progress on Peptide Drugs for Type 2 Diabetes and the Possibility of Oral Administration

Diabetes is a global disease that can lead to a range of complications. Currently, the treatment of type 2 diabetes focuses on oral hypoglycemic drugs and insulin analogues. Studies have shown that drugs such as oral metformin are useful in the treatment of diabetes but can limit the liver’s ability to release sugar. The development of glucose-lowering peptides has provided new options for the treatment of type 2 diabetes. Peptide drugs have low oral utilization due to their easy degradation, short half-life, and difficulty passing through the intestinal mucosa. Therefore, improving the oral utilization of peptide drugs remains an urgent problem. This paper reviews the research progress of peptide drugs in the treatment of diabetes mellitus and proposes that different types of nano-formulation carriers, such as liposomes, self-emulsifying drug delivery systems, and polymer particles, should be combined with peptide drugs for oral administration to improve their absorption in the gastrointestinal tract.

Impacts of a sustainable aviation fuel mandate on airline competition — Full-service carrier vs. low-cost carrier

The aviation industry has proposed the collective goal of achieving net-zero carbon emissions by 2050. In addition to the existing market-based methods (MBMs), the use of renewable energies, in particular, sustainable aviation fuel (SAF), could be one of the most promising means for achieving this long-term target. This paper investigates how an SAF mandate from the government can lead to heterogeneous impacts on two types of airlines, namely, full-service carriers (FSCs) and low-cost carriers (LCCs), that compete in the same markets. A game-theoretic economic model is constructed that accounts for the different service quality levels and cost structures (i.e., fuel efficiency) between FSCs and LCCs. Our analytical results suggest that the SAF mandate favors LCCs over FSCs. The share of SAF blended into fuel raises the airfares of both types of airlines while reducing the traffic and profit of FSCs. The impacts on the LCC traffic and profit depend on its fuel efficiency relative to that of FSC. When LCCs are sufficiently fuel efficient, the SAF mandate can increase their traffic and profit. The government subsidy on airline's SAF use is also analyzed, deriving the optimal subsidy levels for FSC and LCC respectively to achieve pareto-improvement in social welfare and consumer surplus. We also examine how air passengers’ environmental awareness affects the outcomes of SAF mandate implementation. Our economic model also accounts for passengers’ heterogeneous preferences in terms of service quality and price sensitivity.

An ambipolar single-charge pump in silicon

The mechanism of single-charge pumping using a dynamic quantum dot needs to be precisely understood for high-accuracy and universal operation toward applications to quantum current standards and quantum information devices. The type of charge carrier (electron or hole) is an important factor for determining the pumping accuracy, but it has been so far compared just using different devices that could have different potential landscapes. Here, we report measurements of a silicon ambipolar single-charge pump. It allows a comparison between the single-electron and single-hole pumps that share the entrance tunnel barrier, which is a critical part of the pumping operation. By changing the frequency and temperature, we reveal that the entrance barrier has a better energy selectivity in the single-hole pumping, leading to a pumping error rate better than that in the single-electron pumping up to 400 MHz. This result implies that the heavy effective mass of holes is related to the superior characteristics in the single-hole pumping, which would be an important finding for stably realizing accurate single-charge pumping operation.

Giant and negative magnetoresistances in conical magnets in the nonequilibrium Boltzmann equation approach

We study magnetotransport in conical helimagnet crystals using the nonequilibriun Boltzmann equation approach. Spin dependent magnetoresistance exhibits dramatic properties for high and low electron concentrations at different temperatures. For spin up electrons we find negative magnetoresistance despite only considering a single carrier type. For spin down electrons we observe giant magnetoresistance due to depletion of spin down electrons with an applied magnetic field. For spin up carriers, the magnetoresistance is negative, due to the increase in charge carriers with a magnetic field. In addition, we investigate the spin dependent Hall effect. If a magnetic field reaches some critical value for spin down electrons, giant Hall resistance occurs, i.e. Hall current vanishes. This effect is explained by the absence of spin down carriers. For spin up carriers, the Hall constant dramatically decreases with field, due to the increase in spin up electron density. Because of the giant spin dependent magnetoresistance and Hall resistivity, conical helimagnets could be useful in spin switching devices.

A Digital Image Steganographic Detection Method for LSB Steganography

With the advancement of communication technology, communication information can no longer be transmitted merely through text but can be covertly conveyed via various types of communication carriers like images, audio, and video. This brings forth new challenges to traditional detection techniques that mainly target text information. Digital image steganalysis aims to detect and uncover communication information by recognizing steganographic behaviors contained within digital image files. This paper takes digital image steganographic activities based on least significant bit (LSB) as the main research object and conducts analysis and identification of digital images with steganographic information through visual attack method. It has been verified through experiments that steganographic activities based on LSB are hardly detectable through direct visual observation, but can be identified visually after undergoing visual attack processing.

SUBSTANTIATION OF METHODOLOGICAL RECOMMENDATIONS FOR THE USE OF INFORMATION AND MEASURING SYSTEM BUILT ON THE LATEST HARDWARE DEVELOPMENTS DURING THE TESTING OF AME

The constant process of development of both hardware and software perfection inevitably leads to the improvement (creation) of existing (new) advanced information and measurement systems. At the same time, there is a need to develop methodological recommendations for the use of advanced information gathering and processing systems built on the basis of the latest hardware systems and complexes and software products for conducting heterogeneous tests. At the same time, there is a need to develop methodological recommendations for the use of a promising IMS for collecting and processing information built on the basis of the latest hardware systems and complexes and software products for conducting heterogeneous tests. Modern systems used for testing AME are measuring complexes that include modules for connecting sensors, modules for converting analogue sensor signals into digital form, modules for storing the received information in digital form and modules for communication with external computerised devices. Depending on the tasks of the test or experiment, the IMS can be supplemented (simplified) by the need to use certain measuring complexes and systems to measure parameters and obtain reliable information. The ideas, principles and algorithms that currently constitute the methodology of information processing have already made it possible to make a significant breakthrough in information processing technology. Processing methods and principles of their implementation for each field have their own specific features, which are primarily determined by the specific type of information carrier, encoding methods and ways of presenting the results of information processing. As a result, information processing arrangements for different areas often appear to be outwardly dissimilar. However, this external dissimilarity hides the same methodology and principles of building processing systems, which is crucial. The authors of the article study the capabilities of the latest hardware systems and complexes which should be included in advanced IMS and substantiate new methodological approaches, in accordance with regulatory and legal documents, to the use of such IMS during testing of AME.

Non-volatile Fermi level tuning for the control of spin-charge conversion at room temperature

Current silicon-based CMOS devices face physical limitations in downscaling size and power loss, restricting their capability to meet the demands for data storage and information processing of emerging technologies. One possible alternative is to encode the information in a non-volatile magnetic state and manipulate this spin state electronically, as in spintronics. However, current spintronic devices rely on the current-driven control of magnetization, which involves Joule heating and power dissipation. This limitation has motivated intense research into the voltage-driven manipulation of spin signals to achieve energy-efficient device operation. Here, we show non-volatile control of spin-charge conversion at room temperature in graphene-based heterostructures through Fermi level tuning. We use a polymeric ferroelectric film to induce non-volatile charging in graphene. To demonstrate the switching of spin-to-charge conversion we perform ferromagnetic resonance and inverse Edelstein effect experiments. The sign change of output voltage is derived by the change of carrier type, which can be achieved solely by a voltage pulse. Our results provide an alternative approach for the electric-field control of spin-charge conversion, which constitutes a building block for the next generation of spin-orbitronic memory and logic devices.

Effects of lattice instability on the thermoelectric behavior of kagome metal ScV6Sn6

Kagome metal ScV6Sn6 has been a subject of interest due to the emergence of a first-order structural phase transition with intriguing charge density wave behavior below the transition temperature Tc ∼ 92 K. To explore the thermoelectric properties and provide experimental insights into the nature of the phase transition, we have carried out a combined study by means of the electrical resistivity, Seebeck coefficient, and thermal conductivity measurements on single crystalline ScV6Sn6. Pronounced features near Tc have been characterized by all measured physical quantities. In particular, the Seebeck coefficient exhibits a marked reduction as lowering temperature across Tc, attributed to an imbalance of the contribution from different type of carriers induced by the structural phase transition. From the examination of the electronic and lattice thermal conductivities, we obtained a confirmation that the observed enhancement at Tc is essentially caused by the change of the lattice thermal conductivity, demonstrating the primary importance of lattice distortions for the heat transport of ScV6Sn6. In addition, the lattice thermal conductivity above Tc was found to increase monotonically with temperature. We associated the peculiar phenomenon with lattice fluctuations, highlighting the essence of structural instability in the kagome lattice ScV6Sn6. These results add to the knowledge about the thermal transport properties in kagome materials with a hexagonal HfFe6Ge6-type structure.

Overcoming Biopotency Barriers: Advanced Oral Delivery Strategies for Enhancing the Efficacy of Bioactive Food Ingredients.

Bioactive food ingredients contribute to the promotion and maintenance of human health and wellbeing. However, these functional ingredients often exhibit low biopotency after food processing or gastrointestinal transit. Well-designed oral delivery systems can increase the ability of bioactive food ingredients to resist harsh environments inside and outside the human body, as well as allow for controlled or triggered release of bioactives to specific sites in the gastrointestinal tract or other tissues and organs. This review presents the characteristics of common bioactive food ingredients and then highlights the barriers to their biopotency. It also discusses various oral delivery strategies and carrier types that can be used to overcome these biopotency barriers, with a focus on recent advances in the field. Additionally, the advantages and disadvantages of different delivery strategies are highlighted. Finally, the current challenges facing the development of food-grade oral delivery systems are addressed, and areas where future research can lead to new advances and industrial applications of these systems are proposed.

Applying membrane techniques to separate hydrogen from natural gas for hydrogen technologies

Today, the world's energy industry is grappling with several issues arising from restrictions on harmful greenhouse gas emissions, related to climate and environmental protection. Methods of storing energy in various types of carriers are becoming increasingly important, the most promising of which is hydrogen. Various methods of storing it are being considered, where an interesting option is to store it temporarily, under certain conditions, in existing natural gas networks. The challenge, however, is its subsequent recovery. Membrane technology is receiving special attention among recovery methods because of its potential efficiency in hydrogen separation, safety and ease of operation, low energy requirements and environmental friendliness. The paper presents a literature study of the issue, preliminary analyses of membrane gas separation and the advisability of the direction of the new research that has been undertaken. The possibility of applying membrane techniques to the process of separating hydrogen from natural gas in transmission and distribution networks for hydrogen storage technology is presented. Preliminary research is geared toward exploring the scope of applicability of this method of membrane separation, in which the primary goal is to determine the possibility of separating hydrogen from methane. In this paper, within the framework of the adopted simplified structure of the polymeric membrane module, the basic parameters of the process (share of hydrogen in the feed, membrane surface area) were determined, as well as the influence and dependence of transmembrane pressure (permeate) on the values of membrane selectivity, recovery rate and purity of the obtained hydrogen.

Regulation of receptor function in NiCo2O4-SnO2 heterojunction for H2S detection at room temperature

In recent years, the World Health Organization has increasingly emphasized air quality in production environments, leading to heightened societal demands for monitoring of pollutant gases at room temperature. Traditional semiconductor gas-sensitive materials, such as tin oxide (SnO2), have their gas-sensing performance largely limited by their receptor functions, resulting in common issues like low response and poor recovery at room temperature. Spinel-type bimetallic oxides, such as nickel cobaltate (NiCo2O4), offer a unique solution due to their rich adsorption sites on the surface, which provide distinctive receptor functions for detecting toxic gases at room temperature. Herein, NiCo2O4 is synthesized via a one-step hydrothermal method, with a porous spherical cluster structure, and combined with SnO2 to form a heterojunction. The NiCo2O4-SnO2 heterojunction film gas sensor exhibits excellent gas-sensing performance for H2S at room temperature, including high response, short response time, good repeatability, and selectivity. Additionally, the unique receptor functions of the NiCo2O4 were analyzed through first-principles calculations, revealing a semiconductor p-n conversion phenomenon in the presence of H2S gas. The composite also demonstrates a conversion from p-n heterojunction to n-n homojunction during the sensing process, enhancing its gas-sensing performance. This work not only addresses the receptor function limitations of traditional gas-sensitive semiconductor but also provides a feasible approach for controlling carrier types in semiconductors.

Characterization of ZnSe Thin Film Electrodeposited at Room Temperature in Aqueous Medium without Complexing Agents

This study includes a simple electrodeposition technique for the fabrication of ZnSe thin film at room temperature and in an aqueous medium without additional complexing agents. Comprehensive analysis of the optical, structural, and morphological characteristics of the ZnSe thin film electrodeposited onto an ITO substrate was conducted using UV-Vis spectrometry, X-ray diffraction (XRD), Raman spectroscopy, Fourier transform infrared spectroscopy (FT-IR), and field emission–scanning electron microscopy (FE–SEM). Furthermore, the photoelectrochemical properties were evaluated through current-time (I-t) measurements and electrochemical impedance spectroscopy (EIS) under light on/off conditions. Mott-Schottky analysis was also performed to determine the conductivity type, carrier concentration, and flat band potential of the ZnSe thin film. Structural investigations revealed that the ZnSe thin film has a hexagonal structure, the longitudinal optical (LO) phonon mode, stretching and bending vibration modes of Zn-Se. The carrier type of the ZnSe thin film was identified as n- type semiconductor and photoelectrochemical measurements exhibited a photoresponse under the light illumination

Теоретики русского народничества о проблеме нравственной автономии личности

Introduction. The article analyzes the works of Russian populists, which contain a socio-philosophical solution to the problem of moral autonomy of the individual. Theoretical analysis. The socio-philosophical ideal of populist thought was closely connected with the theory of organizing a fair society based on the pattern of social solidarity, which implies socially responsible behavior of citizens who respect other people’s rights and act in the interests of human liberation. Individual autonomy can be achieved through various methods of liberation: through labor activity and the practice of cooperation, socio-political activity in the direction of realizing the social ideal of conscious solidarity. The moral autonomy of the individual, therefore, does not imply moral nihilism, but, on the contrary, is aimed at finding a compromise between private and public interests. Theorists of populism develop the thesis of N. G. Chernyshevsky’s «reasonable egoism», according to which intellectually and morally meaningful individualistic (autonomous) behavior can correspond to collective interests. The moral autonomy of the individual, according to most populists, does not deny the possibility of socially responsible behavior. Conclusion. Populist thought becomes a kind of counterpoint to the development of liberating social thought in Russia, transforming the ideal type of carrier of liberating ideas: a morally autonomous nihilist turns into a socially responsible populist.

Enhancing thermoelectric performance in flexible fabric-based Mo-doped CuAl2O4: Insights into carrier type modification and electrical conductivity optimization

In this work, we report the thermoelectric behaviour of flexible fabric-based Mo doped CuAl2O4. The doped Mo atom occupies the interstitial positions of the spinel lattice of CuAl2O4. This results the lattice expansion and also provides the carrier electrons. Initially, the pristine CuAl2O4 has the carrier concentration of 2.81 × 1014 cm−3, while doping with molybdenum, it not only increases the concentration of the carriers (about −7.65 × 1015 cm−3), but also changes the carrier type. The minimum doping (2 %) of molybdenum to spinel CuAl2O4 (CuAl2O4Mo0.02) creates the fermi level near to the conduction band, which reduces the band gap and results in the effective electrical conductivity as 0.69 Scm−1 at 340 K. The heavy doping enhances the scattering process. This leads to deduction of mobility and lower the electrical conductivity. The highest power factor of 0.0599 μWcm−1K−2 is achieved for the CuAl2O4Mo0.06 sample at 300 K. This is due to the high Seebeck coefficient value of the sample and has an ultralow thermal conductivity value of 0.056 W/mK. The highest output voltage of 3.9 mV is achieved for parallelly connected p-type CuAl2O4 -n-type CuAl2O4Mo0.02 thermoelectric device at the temperature difference of ΔT = 4.1 K. This research findings justify, the doping of molybdenum in the spinel lattice effectively enhances the thermoelectric properties of CuAl2O4 and provide the new ideas for the flexible, wearable fabric based thermoelectric research.

The effect of A-site cations on charge-carrier mobility in Fe-rich amphiboles

Abstract Elucidating the high-temperature behavior of rock-forming minerals such as amphiboles (AB2C5 T8O22W2) is critical for the understanding of large-scale geological processes in the lithosphere and, in particular, the development of high conductivity in the Earth’s interior. Recently, we have shown that at elevated temperatures, CFe-bearing amphiboles with a vacant A site develop two types of charge carriers: (1) small polarons and (2) delocalized H+ ions. To elucidate the effect of A-site cations on the formation and stability of charge carriers within the amphibole structure, here we analyzed synthetic potassic-ferro-richterite as a model Fe-rich amphibole with a fully occupied A site via in situ temperature-dependent Raman spectroscopy. We further compare the results from in situ time-dependent Raman-scattering experiments on pre-heated and rapidly quenched potassic-ferro-richterite and riebeckite as a model Fe-rich amphibole with a vacant A site. We show that the presence of A-site cations (1) reduces the activation temperature of mobile polarons and delocalized H+ cations; (2) decreases the magnitude of the polaron dipole moment; (3) slows down the process of re-localization of electrons on cooling; and (4) makes the electrons inert to rapid change in external conditions, supporting the persistence of a metastable state of pre-activated delocalized electrons even at room temperature. Our results have important geological implications demonstrating that the A-site cations may control the depth of development of high conductivity in subducted amphibole-bearing rocks. Moreover, from the viewpoint of mineral-inspired materials science, our results suggest that the amphibole-structure type has great potential for designing functional materials with tunable anisotropic-conductivity properties.

WITHDRAWN: Recent Advances in the Microbial Synthesis of Human Hemoglobin

Hemoglobin is a major binding protein in human red blood cells and plays an important role in the storage and transportation of oxygen. In recent years, the use of recombinant hemoglobin as a new type of oxygen carrier has attracted widespread attention. So far, the research on recombinant hemoglobin technology is in its early stages and there are still many problems, such as low yield and easy degradation. In this review, we summarize the molecular strategies for recombinant synthesis of human hemoglobin in microorganisms through metabolic engineering and synthetic biology techniques in recent years, and explore the possibility of preparing hemoglobin-based oxygen carriers based on fetal hemoglobin, in order to improve the yield of recombinant human hemoglobin and the sustained stability during protein production through protein engineering strategies, and to possibly reduce the toxic side effects of recombinant hemoglobin products.

Interband and Intraband Hot Carrier-Driven Photocatalysis on Plasmonic Bimetallic Nanoparticles: A Case Study of Au-Cu Alloy Nanoparticles.

Photoexcited nonthermal electrons and holes in metallic nanoparticles, known as hot carriers, can be judiciously harnessed to drive interesting photocatalytic molecule-transforming processes on nanoparticle surfaces. Interband hot carriers are generated upon direct photoexcitation of electronic transitions between different electronic bands, whereas intraband hot carriers are derived from nonradiative decay of plasmonic electron oscillations. Due to their fundamentally distinct photogeneration mechanisms, these two types of hot carriers differ strikingly from each other in terms of energy distribution profiles, lifetimes, diffusion lengths, and relaxation dynamics, thereby exhibiting remarkably different photocatalytic behaviors. The spectral overlap between plasmon resonances and interband transitions has been identified as a key factor that modulates the interband damping of plasmon resonances, which regulates the relative populations, energy distributions, and photocatalytic efficacies of intraband and interband hot carriers in light-illuminated metallic nanoparticles. As exemplified by the Au-Cu alloy nanoparticles investigated in this work, both the resonant frequencies of plasmons and the energy threshold for the d-to-sp interband transitions can be systematically tuned in bimetallic alloy nanoparticles by varying the compositional stoichiometries and particle sizes. Choosing photocatalytic degradation of Rhodamine B as a model reaction, we elaborate on how the variation of the particle sizes and compositional stoichiometries profoundly influences the photocatalytic efficacies of interband and intraband hot carriers in Au-Cu alloy nanoparticles under different photoexcitation conditions.

Marketing Strategies for Financial MCN Institutions in the Era of Integrated Media

The rapid convergence of multiple types of information carriers in the era of integrated media has given rise to the immediate popularity of short-form videos while enhancing the speed and quality of information dissemination, and the Multi-Channel Network (MCN) Institutions behind them have emerged. With the growth of residents' wealth and the increase in demand for investment and financing, MCN institutions focusing on the financial field are attracting more and more attention from the market. Studying the marketing strategies of financial MCN institutions can help improve their business model and is of great significance in promoting the healthy development of investor education. In this paper, we focus on traffic conversion as an essential link in marketing, summarize the common traffic conversion strategies of financial MCN institutions, analyze the case study of JF Wealth Holdings Ltd., and finally provide corresponding strategic suggestions in terms of customer positioning, traffic retention, traffic conversion, and so on.

Tuning the Spin Transition and Carrier Type in Rare-Earth Cobaltates via Compositional Complexity.

There is growing interest in material candidates with properties that can be engineered beyond traditional design limits. Compositionally complex oxides (CCO), often called high entropy oxides, are excellent candidates, wherein a lattice site shares more than four cations, forming single-phase solid solutions with unique properties. However, the nature of compositional complexity in dictating properties remains unclear, with characteristics that are difficult to calculate from first principles. Here, compositional complexity is demonstrated as a tunable parameter in a spin-transition oxide semiconductor La1- x(Nd, Sm, Gd, Y)x/4CoO3, by varying the population x of rare earth cations over 0.00≤ x≤ 0.80. Across the series, increasing complexity is revealed to systematically improve crystallinity, increase the amount of electron versus hole carriers, and tune the spin transition temperature and on-off ratio. At high a population (x = 0.8), Seebeck measurements indicate a crossover from hole-majority to electron-majority conduction without the introduction of conventional electron donors, and tunable complexity is proposed as new method to dope semiconductors. First principles calculations combined with angle resolved photoemission reveal an unconventional doping mechanism of lattice distortions leading to asymmetric hole localization over electrons. Thus, tunable complexity is demonstrated as a facile knob to improve crystallinity, tune electronic transitions, and to dope semiconductors beyond traditional means.