Adjustable Phase Research Articles

Core-shell Ag@C spheres derived from Ag-MOFs with tunable ligand exchanging phase inversion for electromagnetic wave absorption

It has become greatly significant to achieve structurally tunable electromagnetic wave absorption materials (EMAs) derived from metal-organic frameworks (MOFs) via controllably continuous phase inversion. Herein, a series of core–shell Ag@C EMAs were successfully fabricated from Ag-MOFs via adjustable phase inversion. Replacing terephthalic acid (H2BDC) with 2-methylimidazole (Hmim) continuously led to the gradual transformation of Ag-MOF-5 structure into ZIF-L, which determined the crystal and morphological structure of Ag@C EMAs. In addition, due to the optimization of relaxation loss, the minimum reflection loss (RLmin) of S2 reached −50.14 dB with a thickness of 3.0 mm. The EMA derived from the original Ag-MOF had the widest absorption bandwidth (fE) of 5.44 GHz and RLmin of −47.36 dB at only 2.2 mm, respectively. This work can shed new light on the core–shell EMAs derived from phase inversion MOFs, and provide guidance to design novel high-performance EMAs.

Strategies for improving the use of Jakarta City Tour Bus in post-pandemic Covid-19 using IPA Method

Abstract The Jakarta City Tour Bus is one of the strategies of the DKI Jakarta Provincial Government to support the tourism sector. However, in recent years there has been little interest in running the Jakarta City Tour Bus. The lack of some service attributes of the Jakarta City Tour Bus performance and the new phase of adjustment during the Covid-19 pandemic are factors causing the decrease in the number of Jakarta City Tour Bus users since 2019. This study aims to formulate strategies to improve the use of the Jakarta City Tour Bus in the post-pandemic Covid-19 based on user preferences. The analytical method used in this research study is Importance-Performance Analysis (IPA) to formulate strategies for improving the use of Jakarta City Tour Bus in post-pandemic Covid-19. The results showed that there were 11 service attributes of the Jakarta City Tour Bus which had a low level of performance but had a high level of importance. Then, there are strategies to improve the use of Jakarta City Tour Bus which is divided into 2 (two) categories, including the strategies for improving the use of Jakarta City Tour Bus in normal and new normal situations.

Modeling the Dynamics of Salt Marsh Development in Coastal Land Reclamation

AbstractThe valuable ecosystem services of salt marshes are spurring marsh restoration projects around the world. However, it is difficult to determine the final vegetated area based on physical drivers. Herein, we use a 3D fully coupled vegetation‐hydrodynamic‐morphological modeling system to simulate the final vegetation cover and the timescale to reach it under various forcing conditions. Marsh development in our simulations can be divided in three distinctive phases: A preparation phase characterized by sediment accumulation in the absence of vegetation, an encroachment phase in which the vegetated area grows, and an adjustment phase in which the vegetated area remains relatively constant while marsh accretes vertically to compensate for sea level rise. Sediment concentration, settling velocity, sea level rise, and tidal range each comparably affect equilibrium coverage and timescale in different ways. Our simulations show that the Unvegetated‐Vegetated Ratio also relates to sediment budget in marsh development under most conditions.

Postural Threat Influences the Coupling Between Anticipatory and Compensatory Postural Adjustments in Response to an External Perturbation

Fear of falling increases conscious control of balance and postural threat warrants accurate anticipatory motor commands for keeping a safe body posture. This study examines the anticipatory (APAs) and compensatory (CPAs) postural adjustments generated in response to an external perturbation while individuals are positioned at two different altitudes (2 cm and 80 cm) from the floor level. The main result indicates that due to the perceived emotional threat, different agonist and antagonist muscles synergies (R and C-Indexes) are manifested, particularly during the anticipatory phase. The results suggest that the CNS sends central commands for anticipating postural adjustments by adopting primarily a muscle reciprocal activation instead of a muscle co-activation strategy. Interestingly, the APAs strategies were modified under different postural threats by controlling the agonist–antagonist muscles at different joints of lower extremity. For CPAs the reciprocal activation was less applied compared to muscles co-activation to unsure larger margin for compensatory adjustments as needed and re-establish the postural stability. The results indicate that when facing to a postural threat, the CNS modulates the anticipatory and compensatory phases of postural adjustments to minimize the risk of falling.

Measuring landscape evolution from inception to maturity: Insights from a coastal dune system

The concept of the geomorphic cycle is a foundational principle in geology and geomorphology, but the topographic evolution of a single landscape from inception to maturity has been difficult to demonstrate in nature. The onlapping dunes of the Cooloola Sand Mass (CSM) in eastern Australia provide an ideal chronosequence to evaluate landscape evolution. Here commonly assumed properties on which landscape models are based (i.e., conservation of mass and major factors contributing to landscape change) can be physically measured and accounted for. Our field based measurements and forward numerical models demonstrate that dunes, like other landscapes, relax in an exponential manner. The emplaced dunes evolve through an initial phase of rapid topographic adjustment associated with the dominance of landsliding. This phase continues for ∼1 kyr until hillslope gradients are lowered below their angle of repose (0.65 m m−1 or 33°). Once sufficiently lowered, the dunes evolve through slow, soil creep processes. These findings of dual transport regimes are validated by stratigraphic records at all excavated dune foot-slopes and we propose that this evolution can be measured by the distribution of curvature (C) of a landform, specifically its standard deviation (σC), as a measure of surface roughness. Surface roughness smooths with time through diffusional sediment transport that lowers local relief. The value and its rate of smoothing can define the stage in evolutionary development and help infer processes, which makes it an important morphometric tool for understanding landscapes. These observations highlight that under stable evolutionary conditions, the development of the landscape is governed by the physical properties of the dune's parent material. In addition, our findings support landscape evolution inferences from numerical and physical models and the coupling of granular material physics with landscape change.

Multiport Relativistic Magnetron for Phased Array Application

A preliminary investigation on S-band multiport relativistic magnetron (RM) is carried out, which is targeted at the application of high-power microwave (HPM) phased array system. For such system, the phase synchronization and stabilization of sources are crucial. In the proposed multiport RM, the HPMs in four independent output ports are extracted from the same resonant system, thus having the same amplitude and phase naturally. Moreover, the output mode of such multiport RM is fundamental mode, which can achieve Gaussian radiation in the far field directly. Since mode convertors and phase-locked units are no longer necessary, it is beneficial to the miniaturization of HPM phased array system. To further control the phase of output signals, a wide side dimension adjustable phase shifter used for this multiport RM is designed, which could achieve 180° phase shift with a power handling capacity of 568 MW. Particle-in-cell (PIC) simulation of such multiport RM combined with phase shifters applied a diode voltage of 450 kV is carried out. When all output signals are adjusted to be in- phase, an average output power of 265 MW in each port can be obtained, corresponding to a power conversion efficiency up to 65%, and the relative phase differences are controlled within ±2.4%.

Automatic Detoxification Medicine Delivery by Thermo-Sensitive Poly(ethylene glycol)-Based Nanogels.

During the medication-assisted treatment of drug abuse, side effects and addiction liabilities are commonly observed. Thus, control of the medication dose is very important. According to body temperature abnormalities in drug abusers, a thermo-sensitive nanogel was synthesized as a drug carrier to automatically deliver detoxification medicines. This nanogel was prepared through the synthesis of polystyrene (PS) core microspheres, followed by coverage with a nonlinear poly(ethylene glycol)-based copolymer shell. The PS core microspheres were found to be an ideal hydrophobic core for loading the detoxification medicines effectively. The nonlinear poly(ethylene glycol)-based copolymer shell layer consisted of 2-(2-methoxyethoxy)ethyl methacrylate (MEO2MA) and oligo(ethylene glycol) methyl ether methacrylates (Mn = 300 g mol−1, MEO5MA). The monomer feeding molar ratio n(MEO2MA)/n(MEO5MA) of 1:3 enabled PS@P(MEO2MA-co-MEO5MA) nanogels to exhibit a distinguished colloidal stability and an adjustable volume phase transition temperature which is within the drug addicts’ abnormally fluctuating temperature range. Importantly, it was found that the obtained PS@P(MEO2MA-co-MEO5MA) nanogels displayed good biocompatibility with rat aortic endothelial cells in the given concentration range. The nanogels also exhibited a satisfactory loading efficiency and thermo-sensitive/sustained release characteristics for three detoxification medicines: sinomenine, diltiazem and chlorpromazine.

Assessing spatial–temporal heterogeneity of China’s landscape fragmentation in 1980–2020

Exploring the spatial–temporal heterogeneity of landscape fragmentation contributes to realizing the dynamic evolution of the landscape pattern and understanding the impacts of physical-geographical environment and human activities on landscape systems. Differing from previous studies that focused on using single landscape pattern metrics to characterize the landscape fragmentation, this study proposed a Landscape Fragmentation Index (LFI) to assess and analyze the spatial–temporal heterogeneity of China’s landscape fragmentation in 1980–2020. The result showed that the landscape pattern metrics characterizing patch size, patch shape, patch density, patch type, patch cluster, and patch distance were equipped with obvious phased change characteristics, and all of them have successively undergone the stable phase, fluctuation phase, and adjustment phase. In 1980–2020, China’s LFI was gradually increased to 0.393 from 0.383, annually rising by 0.07 percent points on average. Also, the annual average growth of urbanization rate and GDP respectively reached 1 percent point and 9.26 percent points. Besides, regarding spatial pattern, the landscape fragmentation showed relatively obvious fluctuation features in Southwest-Northeast (Hu Line) and Northwest-Southeast (Bole-Taipei Line) directions and Hu Line was manifested as the dividing line of landscape fragmentation while Bole-Taipei Line was shown as the equilibrium line. Spatial-temporal heterogeneity of China’s landscape fragmentation indicated that the fragmented landscape pattern was the combined effect of the physical-geographical environment and human activity interference.

Dynamic Multicompartment Refrigerated Vehicle Routing Problem with Multigraph Based on Real-Time Traffic Information

Aiming at the dynamic multicompartment refrigerated vehicle routing problem with multigraph based on real-time traffic information, this study, based on the idea of preoptimization followed by real-time adjustment, establishes a two-stage mathematical model with minimizing delivery cost. In the preoptimization phase, this study, based on historical traffic information, designed a hybrid chaotic genetic algorithm with variable neighborhood search (HCGAVNS) to obtain the initial delivery scheme. In the real-time adjustment phase, the order in which customers are served remains the same and a path selection strategy is proposed to solve the problem according to the real-time traffic information of different paths. The validity of the model and the algorithm are verified through the analysis of instances. The research results can enrich the related research on cold chain vehicle routing problem and provide a theoretical basis for logistics companies to optimize their delivery scheme.

Different temporal weight-bearing tendencies of persons with right and left hemiplegia while sitting in a wheelchair.

The tendency of persons with hemiplegia to sit for prolonged periods can cause excessive interface pressure (IP) on their buttocks. Due to the different neuromusculoskeletal conditions, different buttock IP relief methods are required for persons with left hemiplegia (LH) and right hemiplegia (RH). Therefore, this study investigates temporal characteristics of IP on the right and left buttocks for RH, LH, and able-bodied individuals (AB) sitting in a wheelchair for 30 min. Thirty-five males participated in the study: 13 LH, 12 RH, and 10 AB. In the initial adjustment phase, the participants maintained an erect sitting posture for 7 min (2 min for posture and 5 min for creep adjustments). After the adjustments, experiments were conducted for 30 min to measure the IP. In the experiments, significant right-sided asymmetries of the mean IP were found for each group (P < 0.05). The right buttocks of LH exhibited significantly more right-sided asymmetry of the mean IP than that of AB (p < 0.01). Moreover, the right buttocks of RH exhibited insignificant asymmetry of the mean IP compared to that of AB (p >0.21). The peak IPs of RH and LH were significantly higher than those of AB (p <0.05), and temporal changes of the mean and peak IP of hemiplegia were significant (p <0.05) and not significant (p >0.05), respectively. The RH exhibited affected-side weight-bearing based on the mean IP. In contrast, the LH relieved the mean IP on the affected-side buttock. Due to the right-sided asymmetric mean and high peak IP, hemiplegia in acute and recovery stages using wheelchairs can cause ulceration. Therefore, different rehabilitation approaches are required for the RH and LH to reduce the peak IP and avoid an uneven distribution of the mean IP.

Patterning All‐Inorganic Halide Perovskite with Adjustable Phase for High‐Resolution Color Filter and Photodetector Arrays

AbstractPerovskite has been actively studied for optoelectronic applications, such as photodetectors and light‐emitting diodes (LEDs), because of its excellent optoelectronic properties. However, ionic bonds of the perovskite structure are vulnerable to chemicals, which makes perovskite incompatible with photolithography processes that use polar solvents. Such incompatibility with photolithography hinders perovskite patterning and device integration. Here, an all‐solution based cesium lead halide perovskite (CsxPbyBrz) patterning method is introduced in which PbBr2 is patterned and then synthesized into CsxPbyBrz. Each step of the top‐down patterning process (e.g., developing, etching, and rinsing) is designed to be compatible with existing photolithography equipment. Structural, chemical, and optical analyses show that the PbBr2 pattern of (10 µm)2 squares is successfully transformed into CsPbBr3 and Cs4PbBr6 with excellent absorption and emission properties. High‐resolution photoconductor arrays and luminescent pattern arrays are fabricated with CsPbBr3 and Cs4PbBr6 on various substrates, including flexible plastic films, to demonstrate their potential applications in image sensors or displays. The research provides a fundamental understanding of the properties and growth of perovskite and promotes technological advancement by preventing degradation during the photolithography process, enabling the integration of perovskite arrays into image sensors and displays.

QUICK-ACTING, CONTROLLABLE PHASE SHIFTER FOR PHASE ANGLE ADJUSTMENT IN RADIO SIGNALS

Subject and Purpose. The phase shifters intended for controlling the phase of radio signals are widely used in ultra-high frequency technology, communication systems, radar, and a variety of measuring and special-purpose radio equipment. Designers of phased array antennas face the need of providing for broad beam scanning angles and high antenna gains, which leads to the necessity of greatly increasing the number of array elements, each of which is to be controlled by a phase shifter. Therefore, the development and creation of quick-acting phase shifters is an urgent task. The purpose of this work is to develop high-speed, controllable phase shifters for performing phase angle adjustments and thus provide, at an acceptable cost, for desirable parameters of phased antenna arrays, frequency stabilizing systems of magnetrons, etc. Methods and Methodology. The functional diagram of the proposed quick-acting, controllable phase shifter has been analyzed mathematically and modelled numerically. Results. The controllable phase shifter can be successfully implemented through the use of two parallel-connected resonators at the input of a specific receiver. Analysis of the signal amplitude and phase at the output of the phase shifter in dependence on the values at the input confirms the possibility of adjusting the phase of the output signal over a wide range of angles. Conclusions. A design concept of quick-acting, controllable phase shifters for producing adjustable phase angles has been developed. The device can be employed in phased antenna arrays or frequency stabilizing systems as a means of improving their operation parameters and reducing their cost at that.

A V-Band Integrated Receiver Front-End Based on 0.15 μm GaAs pHEMT Process for Passive Millimeter-Wave Imaging

The design, analysis, implementation and measurement of an integrated V-band receiver front-end based on 0.15 &#x03BC;m GaAs pHEMT process are presented in this paper. The front-end chip uses the super-heterodyne topology which consists of a low noise amplifier, an image reject mixer, and a multiply-by-four (&#x00D7;4) LO chain. In order to minimize the power consumed by LO chain, an active single-ended mixer is designed which requires extremely low LO power of -5 dBm. Meanwhile, the effect of signal coupling in the integrated chip is analyzed and solutions are proposed. By introducing appropriate filters into the circuit and optimizing the overall layout, the imbalance of in-phase and quadrature signals caused by unwanted coupling can be effectively mitigated, thus enhancing the image rejection of the chip. Probe and module tests are applied to the receiver front-end, and the measurement results reveal that the chip achieves -3 &#x00B1; 0.7 dB conversion gain, 7 dB noise figure and more than 25 dB image rejection ratio in the RF frequency range of 52-56 GHz. Only one supply voltage of 3 V is required for the chip, and total power consumption is 312 mW. Moreover, with a continuously adjustable phase control of 360&#x00B0; and very broadband IF characteristics, the front-end chip is suitable for passive millimeter-wave imaging applications.

The Ranking of the Western Balkan Countries According to the Degree of Globalization

Globalization does not have the same impact on countries, it acts differently in countries with different levels of political, economic, social and technological development. Its unequal distribution by region, country or community confirms that it is a complex and deeply asymmetric process. It is confirmed by numerous theories and debates that only explained and defined the phenomenon, but paid little attention to the complexity of globalization and measuring its extent. Empirical indicators can be used to measure the differences between the national and the international in different domains. In this way, it is possible to see to what extent the countries are globalized, i.e., to see the strong influence of globalization processes on the overall state of society. That is why a large number of countries try to use the processes of globalization to promote national interests and improve their position in international relations. Therefore, the analysis of the indexes of globalization will help us to understand with which components of national power the countries dominate on the regional and global scene. The focus of the research is on the analysis of several globalization indexes that include the countries of the Western Balkan. Namely, the degree of globalization of countries is empirically analyzed through the prism of several different indicators that are constructed to measure the overall index of globalization, as well as to measure the political, economic and social dimension of globalization. The inclusion of a larger number of variables enables a more objective and accurate ranking of countries. As the results of the globalization rating of the Western Balkan countries show, it is concluded that the processes of globalization greatly contribute to strengthening and improving cooperation between countries, intensify interdependence, affect Euro-Atlantic integration processes, stimulate economic growth and improve the situation in societies. However, according to the elaborated data, these countries are still in the phase of adjustment or “maturation”, therefore, they are in the category of partially globalized countries.

Simplified stance limb kinetics patterns revealed during gait initiation in early stage of multiple sclerosis

BackgroundAlthough patients with an early stage of Multiple Sclerosis (MS) commonly complain about balance and gait impairments, their troubles remain misunderstood. The objective was to compare body kinematics and lower limb kinetics during gait initiation between patients with MS with an EDSS score ≤ 4 and healthy participants. MethodsSixteen patients with MS with a median EDSS score of 2.5 [0–4] and disease duration of 7.4 ± 4.2 years, as well as 16 healthy participants were included, and 3-D motion analysis was performed during gait initiation to calculate spatiotemporal, kinematic and kinetic parameters. FindingsThe center of pressure position at the beginning of the gait initiation was more anterior (p = 0.02) in patients with MS than healthy participants. The kinetic parameters of the stance limb were highly affected in patients with MS compared to healthy participants during gait initiation. The net muscular moments for each joint were significantly different during the anticipatory postural adjustment phase with smoother variations for patients with MS compared to healthy participants. InterpretationEarly stage MS strongly affects the motor modulation of stance limb kinetics during the anticipatory postural adjustment of gait initiation, without alteration of the execution phase. The net muscular moments are sensitive in detecting unobservable balance impairments and can be used to assess disease progression at the early stage. These results suggest that early rehabilitation programs aimed at improving motor modulation and flexibility in gait initiation should be implemented.

A review of recent progress and developments in China smart cities

Since 2008, the development of China's smarter cities has experienced four phases: Exploration and practice phase, normative adjustment phase, strategic breakthrough phase and all-round development phase. A number of innovative practices such as the city brain and ‘unified online government service’ have provided the world with Chinese solutions for smart city construction. This study explains the concept and connotation of innovative smarter cities, summarizes the development status of China's innovative smarter cities, analyses and judges the seven development trends in the construction of innovative smarter cities, analyses the shortcomings and deficiencies, and puts forward policy suggestions to promote the development. It has an important reference value for comprehensively understanding the development concept and overall development status of China's innovative smarter cities and clarifying the next development direction.

PSO-based Power-Driven X-Routing Algorithm in semiconductor design for predictive intelligence of IoT applications

As the Internet of Things (IoT) becomes more and more intelligent, a new computing paradigm, predictive intelligence is incorporated into many IoT applications. The devices of predictive intelligence in IoT applications must consider the power and delay consumption. As the Power-Driven X-Routing (PDXR) problem model under the advanced semiconductor design, the length-restricted condition in the multi-dynamic voltage model is introduced to save power consumption and the X-architecture is introduced to better reduce the wirelength to optimize the chip delay. To this end, an effective particle swarm optimization-based power-driven length-restricted X-routing algorithm is proposed for predictive intelligence in IoT applications. Firstly, a pre-calculated lookup table is designed to provide fast information query for the subsequent algorithm flow. Secondly, an improved particle swarm optimization algorithm is presented for the discrete PDXR problem. Thirdly, in the adjustment phase, the choice of intermediate nodes is expanded, and is no longer limited to the corner points of obstacles. Fourthly, a removal strategy of redundant points is proposed to optimize the routing path. Finally, the wirelength is further reduced by a local topology optimization strategy. The experimental results show that the proposed algorithm can achieve the best wirelength cost at a very fast speed under the constraint of restricted wirelength, so as to better satisfy the demand of the power and delay performance of semiconductor design for predictive intelligence in IoT applications.

The Effects of Lower Extremity Kinesio Taping on Temporal and Spatial Parameters of Gait Initiation in Semi-professional Soccer Players With and Without Functional Ankle Instability

Introduction: The present study aimed to investigate the immediate effects of two types of Kinesio taping on the temporal and spatial variables of gait initiation in individuals with and without Functional Ankle Instability (FAI). Materials and Methods: Thirty semi-professional athletes (15 with and 15 without FAI [control]) were recruited for this study. The gait initiation task was examined before and after the two types of Kinesio taping on a force plate. Temporal (Reaction Phase [RP], Anticipatory Postural Adjustment Phase [APAP]), and spatial variables were recorded and compared between Groups, before and after the tape application. Results: The results of multiple repeated-measure analyses of variance showed no significant differences for “factor” and “Group by factor” interaction effects for any outcome measure (P&gt;0.05). There were no significant differences for Group effects except for the APAP (F=10.27, P=0.003). The APAA was 71.95 ms longer in the FAI Group (476.95±15.87 ms) compared to the control Group (405.04±15.87 ms). Conclusion: Kinesio taping application does not influence any of the gait initiation parameters on the force plate. Participants with FAI demonstrated longer APAP which might be due to recurrent injury and instability during sports or physical activity.

Multi-Virtual-Vector Model Predictive Current Control for Dual Three-Phase PMSM

This paper proposes a multi-virtual-vector model predictive control (MPC) for a dual three-phase permanent magnet synchronous machine (DTP-PMSM), which aims to regulate the currents in both fundamental and harmonic subspace. Apart from the fundamental α-β subspace, the harmonic subspace termed x-y is decoupled in multiphase PMSM according to vector space decomposition (VSD). Hence, the regulation of x-y currents is of paramount importance to improve control performance. In order to take into account both fundamental and harmonic subspaces, this paper presents a multi-virtual-vector model predictive control (MVV-MPC) scheme to significantly improve the steady performance without affecting the dynamic response. In this way, virtual vectors are pre-synthesized to eliminate the components in the x-y subspace and then a vector with adjustable phase and amplitude is composed of two effective virtual vectors and a zero vector. As a result, an enhanced current tracking ability is acquired due to the expanded output range of the voltage vector. Lastly, both simulation and experimental results are given to confirm the feasibility of the proposed MVV-MPC for DTP-PMSM.

A Study on the Relationship between Postural Control and Pain-Related Clinical Outcomes in Patients with Chronic Nonspecific Low Back Pain.

Objectives To explore the relationship between postural control and pain-related clinical outcomes in patients with chronic nonspecific low back pain (cNLBP). Methods Participants with cNLBP and healthy individuals were recruited. Muscle activities were recorded during internal and external perturbation tasks. Postural control capacity was assessed by muscle onset time and integrals of electromyography (iEMGs) of postural muscles during the phases of anticipatory postural adjustments (APAs) and compensatory postural adjustments (CPAs). Correlation analysis was employed to investigate the relationship between postural control capacity, pain, and disability. Results Twenty-seven patients with cNLBP and 27 healthy participants were recruited. Gastrocnemius (GA) muscle onset time was earlier in the cNLBP group than in the control group in the internal perturbation task. The onset time of GA and erector spinae (ES) of the cNLBP group was later than that of the controls in the external perturbation task. Disability level moderately correlated with the iEMGs of rectus abdominis (RA), GA, and external oblique (EO) during APAs. Pain score moderately correlated with the iEMGs of RA, EO, and ES during CPAs of perturbation tasks. Conclusion cNLBP participants had altered muscle activation strategy to maintain postural stability in response to perturbation. This study further discovered that pain-related disabilities of cNLBP participants were likely related to the APAs capacity, whereas the pain intensity may relate to the CPAs capacity. Pain and disability may therefore be related to the control process of the posture-related muscles.