Basic Modes Research Articles

A novel switchable water stationary phase for supercritical fluid chromatography

A novel pH switchable water stationary phase is presented for use in supercritical fluid chromatography (SFC). By adding NH4OH to the water coating and system hydration, changes in CO2 pressure and temperature allow a wide range of stationary phase pH conditions (∼3–9) to be achieved, which impact analyte retention properties. For example, 100 atm and 50 °C produces an acidic water stationary phase (pH near 4.0) where octanoic acid readily elutes while the base caffeine does not. Conversely, at 80 atm and 120 °C a basic water stationary phase (pH near 8.0) is obtained and the opposite occurs. Further, under constant pressure and temperature conditions, simply adding or removing NH4OH from the system is also found to readily allow switching between the basic and acidic water stationary phase modes and demonstrates control over ionizable analyte elution. For instance, hexanoic acid elution is near 40 times more delayed on a basic water stationary phase and, as such, it can be eluted at later points in time as desired by removing the NH4OH and switching to an acidic stationary phase. Experiments indicate that stationary phase pH switching occurs uniformly across the 15 m column length within about 18 s and that analyte retention times are very reproducible upon performing a switch (1.4% RSD; n = 3). Results demonstrate the selectivity factor between acidic and neutral analytes can be reversed and increased about 35 times, while in other trials resolution also similarly increased near 40-fold. By rapidly switching the stationary phase pH back and forth between acidic and basic modes, the selectivity between ionizable analytes could also be increased as desired. Various applications with the system show that it can vastly increase the separation between target analytes and matrix components as required by the dynamics of a particular separation.

RHex-T3: A Transformable Hexapod Robot With Ladder Climbing Function

To realize a wide range of functions in a complex environment, the transition is necessary between various motions suited to each environment. This article presents a transformable hexapod robot, RHex-T3, which is capable of switching to leg, wheel, and RHex mobile modes to improve its flexibility, and climbing the ladders with the hook-mode. The mechanical design and the implementation of the RHex-T3 are introduced, especially the coaxial transmission mechanism and the innovative 2-degree-of-freedom transformable leg. As the result, experiments are conducted to demonstrate the feasibility and successful performance of the proposed coaxial transformable mechanism. The locomotion performance under three basic mobile modes is evaluated through a series of indoor and outdoor experiments. Furthermore, the ladder climbing function is also verified and its boundary conditions are discussed.

Plug & play origami modules with all-purpose deformation modes

Three basic deformation modes of an object (bending, twisting, and contraction/extension) along with their various combinations and delicate controls lead to diverse locomotion. As a result, seeking mechanisms to achieve simple to complex deformation modes in a controllable manner is a focal point in related engineering fields. Here, a pneumatic-driven, origami-based deformation unit that offers all-purpose deformation modes, namely, three decoupled basic motion types and four combinations of these three basic types, with seven distinct motion modes in total through one origami module, was created and precisely controlled through various pressurization schemes. These all-purpose origami-based modules can be readily assembled as needed, even during operation, which enables plug-and-play characteristics. These origami modules with all-purpose deformation modes offer unprecedented opportunities for soft robots in performing complex tasks, which were successfully demonstrated in this work.

Implementation of an Adaptive Method for Changing the Frequency Division of the Counter Clock Signal in a Frequency-to-Code Converter

Processing physical quantities into an indirect signal is a standard method of transferring information about the measured quantity to the master system, which analyzes the data obtained from the acquisition system. The intermediate signal is very often the voltage, but another transmission medium can be the frequency of the output signal of the “physical quantity-to-frequency” converter. The article presents the implementation of the adaptive method of selecting the clock signal frequency of the counter working in the converter. The issue of selecting the clock signal frequency for the required processing range of the transducer is discussed in detail. The application of the method using the STM32L476RG microcontroller is presented. The principle of checking the processing range of the developed transducer model is discussed. The algorithms of transducer operation in basic and adaptive modes of measuring the period of the variable frequency signal are proposed. The results of operation, in both modes, of the transducer model of frequency processing are presented, along with the metrological analysis of the results. The influence of selected approximations used to reconstruct the measured quantity on the final presentation of the measurement result is discussed.

A high‐efficiency magnetic‐geared double‐rotor machine with the coreless stator for hybrid aircraft propulsion

AbstractMagnetic‐geared double‐rotor machines are recognized as a promising power‐splitting component in hybrid electric aircrafts (HEAs). However, the high fuel efficiency speed of the turbine engine in HEAs is about 10,000 rpm, whereas conventional topologies suffer from low efficiency at high speed due to its specific operation principle—the magnetic field modulating principle. A coreless stator magnetic‐geared double‐rotor machine (CS‐MGDRM) is proposed to enhance high‐speed efficiency and thus comply with the operation condition of HEAs. First, the machine structure and hybrid propulsion system configuration are introduced, and power‐flow analysis of three basic operation modes is presented. Second, the operation principle of the machine is illustrated, and investigation of electromagnetic performances is carried out by finite element analysis. Third, an analytical model of the machine is developed, based on which the design optimization towards the maximum torque capacity is investigated. Furthermore, the loss distribution law and transmission efficiency are analysed and compared with conventional scheme, and the power factor characteristic is investigated as well. Finally, the overall performance of the proposed machine is evaluated.

Computational Technology for the Basis and Coefficients of Geodynamo Spectral Models in the Maple System

Spectral models are often used in the study of geodynamo problems. Physical fields in these models are presented as stationary basic modes combinations with time-dependent amplitudes. To construct a model it is necessary to calculate the modes parameters, and to calculate the model coefficients (the Galerkin coefficients). These coefficients are integrals of complex multiplicative combinations of modes and differential operators. The paper proposes computing technology for the calculation of parameters, the derivation of integrands and the calculation of the integrals themselves. The technology is based on computer algebra methods. The main elements for implementation of technology in the Maple system are described. The proposed computational technology makes it possible to quickly and accurately construct fairly wide classes of new geodynamo spectral models.

Waves in Magnetosheath Jets—Classification and the Search for Generation Mechanisms Using MMS Burst Mode Data

AbstractMagnetosheath jets are localized dynamic pressure enhancements in the magnetosheath. We make use of the high time resolution burst mode data of the Magnetospheric Multiscale mission for an analysis of waves in plasmas associated with three magnetosheath jets. We find both electromagnetic and electrostatic waves over the frequency range from 0 to 4 kHz that can be probed by the instruments on board the MMS spacecraft. At high frequencies we find electrostatic solitary waves, electron acoustic waves, and whistler waves. Electron acoustic waves and whistler waves show the typical properties expected from theory assuming approximations of a homogeneous plasma and linearity. In addition, 0.2 Hz waves in the magnetic field, 1 Hz electromagnetic waves, and lower hybrid waves are observed. For these waves the approximation of a homogeneous plasma does not hold anymore and the observed waves show properties from several different basic wave modes. In addition, we investigate how the various types of waves are generated. We show evidence that, the 1 Hz waves are connected to gradients in the density and magnetic field. The whistler waves are generated by a butterfly‐shaped pitch‐angle distribution and the electron acoustic waves by a cold electron population. The lower hybrid waves are probably generated by currents at the boundary of the jets. As for the other waves we can only speculate about the generation mechanism due to limitations of the instruments. Studying waves in jets will help to address the microphysics in jets which can help to understand the evolution of jets better.

Recent Progress in Self-Powered Sensors Based on Liquid-Solid Triboelectric Nanogenerators.

Recently, there has been a growing need for sensors that can operate autonomously without requiring an external power source. This is especially important in applications where conventional power sources, such as batteries, are impractical or difficult to replace. Self-powered sensors have emerged as a promising solution to this challenge, offering a range of benefits such as low cost, high stability, and environmental friendliness. One of the most promising self-powered sensor technologies is the L-S TENG, which stands for liquid-solid triboelectric nanogenerator. This technology works by harnessing the mechanical energy generated by external stimuli such as pressure, touch, or vibration, and converting it into electrical energy that can be used to power sensors and other electronic devices. Therefore, self-powered sensors based on L-S TENGs-which provide numerous benefits such as rapid responses, portability, cost-effectiveness, and miniaturization-are critical for increasing living standards and optimizing industrial processes. In this review paper, the working principle with three basic modes is first briefly introduced. After that, the parameters that affect L-S TENGs are reviewed based on the properties of the liquid and solid phases. With different working principles, L-S TENGs have been used to design many structures that function as self-powered sensors for pressure/force change, liquid flow motion, concentration, and chemical detection or biochemical sensing. Moreover, the continuous output signal of a TENG plays an important role in the functioning of real-time sensors that is vital for the growth of the Internet of Things.

Experimental and simulated TD-DFT study of malachite green dye and tetrahydroquinoxaline hybrid blend: Its application removal from wastewater

2-Carbethoxy-3-oxo-1,2,3,4-tetrahydroquinoxaline (CTQ) was synthesized using a condensation reaction between o-phenylenediamine and diethylbromomalonate under regulated conditions. CTQ compound was used as a powerful adsorbent in the elimination of harmful malachite green (MG) dye from wastewater using the spectrophotometer technique. By applying Hartree-Fock (HF) and density functional theory (DFT-B3LYP) with 6-31G(d,p) as the basis, the optimized geometries, vibrational wavenumbers, intensities of vibrational bands, and various atomic charges of 9VC have been investigated. The basic vibrational modes measured experimentally are analyzed and compared to theoretical predictions. Density functional theory (DFT) was used to examine the geometry, electronic structure, polarizability, and hyperpolarizability of the hybrid blend organic dye (CTQ+MG)HB, which contains π-conjugated tetrahydroquinoxaline unit with an electron donor-acceptor moiety, and time-dependent DFT (TD-DFT) with several hybrid functionals were used to examine the electronic absorption spectrum. Various factors affecting the removal of this toxic dye like adsorbent dose, contact time, initial dye concentration, and dye solution temperature were examined. To show the equilibrium of the adsorption, Freundlich and Langmuir isotherm models were utilized. Freundlich and Langmuir's equations' correlation coefficient values were found to be in perfect agreement. The transfer of MG to quinoxaline is regulated by a pseudo-second-order procedure. The adsorption approach was a spontaneous and exothermic type. A suitable reaction mechanism has also been described and explored in this study along with an analysis of the thermodynamic parameters.

Lean-back and lean-forward online behaviors: The role of emotions in passive versus proactive information diffusion of social media content.

One of the main drivers of social media's influence is the easy way of generating information cascades via forwarding messages. Two basic modes of forwarding information consist in sharing it without changes (lean-back) or adding or modifying the content of the original message (lean-forward). In this work, we study these two modes of online information sharing. Using data from six cases extracted from Twitter, in which retweets make up most of the content, we analyzed emotions in passive versus proactive information diffusion. Our findings show that emotional valence does not indicate significant differences between lean behaviors, while the activation level of emotions presents contrasts. For example, disgust is more intense in lean-back and anger in lean-forward behavior. We also find that in proactive lean-forward communication, disgust and joy synchronize with the emotions of lean-back messages. Finally, a causal analysis of lean-forward information sharing reveals that disgust provokes a consistent increment of itself while it also decreases the appearance of anger in political topics. We discuss the implications of our findings for the study of emotions in active versus passive forwarding of information in social media.

High Fidelity Hydroelastic Analysis Using Modal Matrix Reduction

Structural assessment is a main concern when designing and operating any sort of offshore structure. This assessment is meant to ensure that the structural integrity is preserved along the lifespan of the asset, withstanding the worst sea-states that will be encountered and making sure that the accumulated fatigue damage will not jeopardize its structural integrity neither. The purpose of this paper is to present a fast and reliable hydroelastic model. This model is based on time-domain tight-coupling of a three-dimensional FEM (finite element method) linear structural model and a three-dimensional FEM seakeeping hydrodynamics model. In order to reduce the computational cost of structural dynamic simulations, the high-fidelity structural solution is projected onto the modal basis to obtain the modal matrix system and to extend the response amplitude operators (RAO) to the modal responses (MRAO). From there, the number of structural degrees of freedom can be greatly reduced by retaining only those eigenmodes preserving most of the structural elastic energy. The use MRAOs and/or the large reduction in structural degrees of freedom allows us to: first, quickly analyse the large number of loadcases required on the design stage; and second, to implement a digital twin for structural health monitoring in operational conditions. The paper also presents an application case of the developed methodology.

Insights into the Morphology and Surface Properties of Microalgae at the Nanoscale by Atomic Force Microscopy (AFM): A Review

Atomic force microscopy (AFM) is a method that provides the nanometer-resolution three-dimensional imaging of living cells in their native state in their natural physiological environment. In addition, AFM’s sensitivity to measure interaction forces in the piconewton range enables researchers to probe surface properties, such as elasticity, viscoelasticity, hydrophobicity and adhesion. Despite the growing number of applications of AFM as a method to study biological systems, AFM is not yet an established technique for studying microalgae. Following a brief introduction to the basic principles and operation modes of AFM, this review highlights the major contributions of AFM in the field of microalgae research. A pioneering AFM study on microalgae was performed on diatoms, revealing the fine structural details of diatom frustule, without the need for sample modification. While, to date, diatoms are the most studied class of microalgae using AFM, it has also been used to study microalgae belonging to other classes. Besides using AFM for the morphological characterization of microalgae at the single cell level, AFM has also been used to study the surface properties of microalgal cells, with cell elasticity being most frequently studied one. Here, we also present our preliminary results on the viscoelastic properties of microalgae cell (Dunaliella tertiolecta), as the first microrheological study of microalgae. Overall, the studies presented show that AFM, with its multiparametric characterization, alone or in combination with other complementary techniques, can address many outstanding questions in the field of microalgae.

Unbalanced regression sample generation algorithm based on confrontation

Data imbalance is an issue because the number of samples in different categories or target value ranges varies significantly. Numerous studies have been developed to address the data imbalance problem in classification samples. However, the issue of data imbalance in regression samples has not been researched well. The distribution of the target value of regression samples with the unbalanced data problem is more complicated than classification samples with the unbalanced data problem due to the continuity of the target values of regression samples. To solve this problem, we defined three basic modes of the data imbalance problem of regression samples: PSIR-mode (Positive Skewed Imbalanced Regression-mode), UNIR-mode (Un-Normal Imbalanced Regression-mode) and NSIR-mode (Negative Skewed Imbalanced Regression-mode). Any regression samples having data imbalance problems with complex target value distributions can be split into these three modes. To solve the data imbalance problem in regression samples, we proposed the DIRVAE (Deep Imbalanced Regression Variational Autoencoder) algorithm to generate missing and minority samples. The model can learn the distribution information of the original sample and the sample information between adjacent samples in the target value distribution. Experiments in biology, medicine and aerospace have proved the superiority of the model.

Layout Aware Optimization Methodology for SOT-MRAM Based on Technically Feasible Top-Pinned Magnetic Tunnel Junction Process

The emerging spin-orbit torque magnetic random-access memory (SOT-MRAM) shows promising prospects in high-level cache applications due to its sub-nanosecond switching speed and high reliability. However, SOT-MRAM faces the issue of large bit-cell layout area, which is currently the focus of attention. Although many design and evaluation works have emerged, the lack of a unified standard for realistic SOT process has hindered the development of relevant research towards practicality. In this paper, the bit-cell area of the SOT-MRAM will be evaluated and optimized based on the technically-feasible process. First of all, based on the state-of-the-art top-pinned SOT nanopillar process, the SOT-MRAM design rules are proposed. On this basis, this paper systematically summarizes four basic device layout modes and provides optimized layout suggestions for conventional SOT bit-cells with different types and sizes of devices. In addition, a series of area-efficient SOT bit-cell designs based on the common area (CA) and dual common (DC) solutions are proposed, which can reduce the layout area of SOT bit-cells by up to 38.4% with reasonable write latency and energy overhead.

북한 민요 5음음계 조식확장 양상에 관한 연구

The North Korean folk Music is characterized by the pentatonic scale, which is made up of the five tones of gong (C), shang (D), jue (E), zhi (G), and yu (A).
 There are five corresponding modes in it: gong mode, shang mode, jue mode, zhi mode and yu mode. It contains a unique 'sigimsae' (decorative expressions) and and exhibits a unique style. Given the researches on the pentatonic scale modes in the North Korean folk Music from 1950 to 2000, it is divided into studies on structural characteristics and types of the modes based on 'pyongjo three-tone serial' and 'gemyongjo three-tone serial' and studies on the mode expansion.
 Among those, the researches on the mode expansion are generally based on Hwang Min-myung's theory.
 This study examines the theoretical background and formation process of the pentatonic scale modes in the North Korean folk songs and analyzes the structure and tone characteristics between 'basic scale modes' and 'expanded scale modes', which have not yet been studied by the theory of expansion of the pentatonic scale modes in folk songs. Furthere, it seeks theoretical study on the modal development, aspects of modulation, and aspects of modal change in the same serial of extended scale modes. Therefore, this studycomposes the mode scales based on Hwang Min-myung's theory of the expansion of the pentatonic scale modes and divides the corresponding extended modes into 9 types. Among them, it is found that 'same serial modulation' and 'same tonic-note modulation' are made between scale modes due to the characteristics of 'same serials' and 'same scale modes' that appear in modes and extended scale modes in accordance to the alternative notes such as B, Bb, C#, Eb, F, and F#.
 This study aims to suggest the possibility of the development of the pentatonic scale modes in the Korean folk music. Therefore, it is expected that research on the pentatonic scale modes in Korea and other countries around the world will serve as a theoretical foundation for the creation of music by presenting the direction of research results that strengthen the basic frame of theory.

Aiming for high-capacity multi-modal free-space optical transmission leveraging complete modal basis sets

Free-space optical (FSO) communication has gained much interest due to its capability of providing not only a cost-efficient solution where the optical fiber is too expensive or too difficult to deploy but also a much higher system capacity than its radio-frequency competitor. In addition to conventional polarization-division multiplexing and coherent detection, combining with mode-division multiplexing can unlock the full potential of FSO communications and achieve ultra-high spectral efficiency. In this paper, we review the recent progress of multi-modal FSO communication systems leveraging complete modal basis sets. Some practical issues for system design are discussed. We also present two latest demonstrations that achieved the record-high single-wavelength data rate using a commercial transponder and a pair of commercial multiplexer/demultiplexer for multi-modal FSO transmission without turbulence and in atmospheric turbulence, respectively, showing the potential of such a technique.

A review on Rayleigh-Bénard convection influenced by the complicating factors

Thermal convection is one of the basic modes (thermal convection, thermal conduction, thermal radiation) of heat transfer, and it belongs to the thermo-fluid mechanics. With the development and progress of science and technology, as well as the cross accommodation of disciplines, new contents and challenges arise in the thermal convection. For instance, along with the increasing energy consumption all over the world, the enhanced energy transport has attracted more and more attentions, which is inseparable from the development of thermal convection. As a classical model of natural convection, the Rayleigh-Bénard (RB) convection has been investigated for more than 100 years and numerous research findings have been obtained. However, it is still one of the most notable subjects, particularly the complex flow and heat transport problems of the stabilizing-destabilizing flow. This review, therefore, focuses on the RB convection researches, as well as natural convection of other configurations, under the influence of various complicating factors, including thermal radiation, magnetic field, rotation and electrical field. The flow and transport characteristics, especially the heat transfer, are summarized and analyzed. Although these factors usually show a stabilizing effect, like the delay of the onset of instabilities, it is quite surprising that there is a counterintuitive but significant flux enhancement within the specific strength range. Finally, some topics of future work are prospected briefly, such as the multi-fields coupling problem, the ultimate regime with additional field effects and the unifying view on strengthening mechanism of stabilizing effects.

Exploration of Innovative Training Mode of School-enterprise Network Marketing

The characteristic of higher vocational education is to pay attention to the cultivation of students' skills, practice and professionalism, and the construction of off-campus practical training base is the key to realize the above skills of students. Both off-campus training bases and on-campus training bases are important components of practical teaching in higher vocational colleges. There are great differences between them in basic functions, functions, operation and management modes. With the reform and rapid development of national vocational education, the advanced concepts of teaching, teaching materials and teaching methods are constantly updated. Under the basic background of ideological and political construction of the course, innovation and entrepreneurship drive, the reconstruction of teaching content, loose leaf teaching materials and project-based teaching method can be flexibly applied in the actual teaching of network marketing comprehensive practical training course. While improving the teaching effect on campus, higher vocational colleges should enhance their ability to serve the regional economy, integrate social services with curriculum construction, and improve teachers' social service ability by means of the integration platform of production and education.

Массовая коммуникация как онтологический фон современной культуры

The article analyzes the history of the development of forms, methods and means of communication as one of the main factors in the civilizational development of mankind. The author agrees with M. McLuhan's periodization, supplementing it with specific characteristics of the current stage in the development of communication, which can be designated as mass communication. Among its constitutive features stand out: derealization, glocalization, individualization, publicity, the disappearance of intimacy and semantic involution. Communication is defined as a mode of existence of modern man and, more broadly, modern society. Identity, basic modes of activity, formats of existence – all this is somehow connected with mass communication, which has become the ontological framework of culture. New media allow a significant increase in the participation of their users, who are no longer passive recipients of information, but actively produce content and information. There is a negative trend of devaluation of traditional forms of communication, within which significant values were articulated and cultivated, contributing to the consolidation and solidarity of society. The question is raised about the possible threats of uncontrolled development of modern forms of culture based on a high speed of message transmission, which, in the author's opinion, leads to the disappearance of the option of deep reflection, the possibility of understanding at the level of the whole. Digitalization threatens the barbarization of society, its return to the state of the dark Middle Ages, when the value of personal and autonomous intentions is leveled, and thoughtless collectivity comes in their place.

Dynamic performance of co-cured composite structure with sandwich damping film

In this paper, a research on theoretical analysis and finite element simulation of the damping sandwich composite plate with fixed support condition is carried out, and the dynamic characteristics of composite plates are explored by modal experiments. The vibration equilibrium equation of damping sandwich composite plate with fixed support condition is derived by combining first-order shear deformation theory, variational principle, and Hamilton principle. A set of modal basis functions satisfying the fixed support condition are established. The analytical solution is obtained via Galerkin weighted residual theory. The influence of structural parameters on the free vibration characteristics of the sandwich composite plates is investigated based on the mutual verification of theoretical calculation, numerical simulation, and modal test results. When the damping layer (0.2 mm) is located on the surface of the skin (2 mm), the first-order mode frequency and first-order loss factor are 196.66 Hz and 0.01, respectively. When the damping layer is in the neutral layer, the first-order mode frequency and first-order loss factor are 189.99 Hz and 0.14, respectively. Compared with the damping layer in the skin, the first-order mode frequency is reduced by 3.39%, while the first-order loss factor is 14 times higher. The results show that the damping performance of the structure is optimal when the damping layer is located in the neutral layer, and the structural stiffness is higher when the damping layer is close to the skin. The work provides theoretical guidance for the development and application of lightweight composite structures with large damping and high stiffness.