Small-sized Structure Research Articles

Characterization of bamboo shoots dietary fiber modified by ball milling and its role in altering the physicochemical properties of shrimp surimi

A simple but robust strategy of ball milling (20 Hz, 30 Hz for 30 s, 60 s, 120 s, 180 s) was utilized to modify bamboo shoots fiber (BSDF) in shrimp surimi. The water holding capacity, swelling capacity, and oil binding capacity of 30 Hz-60 s milled BSDF exhibited the highest values of 5.61 g/g, 3.13 mL/g, and 6.93 g/g, significantly higher (P < 0.05) than untreated one (3.65 g/g, 2.03 mL/g, 4.57 g/g). Ball-milled BSDF exhibited a small-sized structure with the relative crystallinity decreased from 40.44 % (control) to 11.12 % (30 Hz-180 s). The myosin thermal stability, gelation properties of surimi were significantly enhanced by incorporating 20 Hz-120 s and 30 Hz-60 s BSDF via promoting protein unfolding, covalent hydrophobic interactions, and hydrogen bonding. A matrix-reinforcing and water entrapping effect was observed, exhibiting reinforced networks with down-sized water tunnels. However, BSDF modified at 180 s contributed to over-aggregated networks with fractures and enlarged gaps. Appropriate ball-milled BSDF (20 Hz-120 s, and 30 Hz-60 s) resulted in a significant decrease in α-helix (P < 0.05), accompanied by an increase of β-sheets and β-turn. This work could bring some insights into the applications of modified BSDF and its roles in the gelation of surimi-based food.

V-MOFs derived Na3V2(PO4)3/C core-shell spheres toward ultrastable sodium-ion batteries

Due to the large ionic radius of sodium-ion, the transport of ions is hindered, leading to slow ion diffusion. This, in turn, results in significant structural stresses, causing rapid material deterioration and reduced cycle stability. Furthermore, the low electronic conductivity of Na3V2(PO4)3 further contributes to the unsatisfactory rate performance. To address these challenges, we have employed an adjustable V-MOFs as precursors to synthesize Na3V2(PO4)3/C core-shell spheres with tunable sizes. The incorporation of a carbon shell serves a dual purpose: it not only alleviates the structural stress experienced during charge and discharge processes but also facilitates rapid electron conduction. Moreover, the small-sized core-shell structure effectively shortens the ion and electron transport distances while providing more reactive sites, thus enhancing the kinetics. Consequently, the NVP-0.01M sample obtained exhibits exceptional rate performance, with a remarkable reversible capacity of 115.1 mAh g−1 at 0.1C and 92.2 mAh g−1 at 30C. Furthermore, this material demonstrates remarkable long-term stability, as evidenced by a specific discharge capacity of 99.3 mAh g−1 even after 500 cycles at 1C, corresponding to a capacity retention rate of 91.3 %. The NVP-0.01M∥HC full cell also display outstanding electrochemical performance. This research introduces a novel approach for synthesizing high-performance cathode materials specifically designed for sodium-ion batteries.

Highly crystalline carbon nitride with small-sized sea urchin-like structure for efficient photocatalytic hydrogen production under visible-light irradiation

Molten-salt method has been deemed as a feasible strategy to increase the crystallinity of graphitic carbon nitride (abbreviated as CN), thereby improving its photocatalytic activity. However, highly crystalline CN prepared by molten-salt method using bulk carbon nitride (BCN) as the precursor still suffers from a small specific surface area, which is unfavorable to the separation of photogenerated carriers. Here, we report a facile approach to obtain highly crystalline CN with a large specific surface area using tubular carbon nitride (TCN) as raw material, and the final sample is named as tubular carbon nitride-molten salt (TCN-M). Compared with bulk carbon nitride-molten salt (BCN-M) sample, the obtained TCN-M sample not only retains the advantage of high crystallinity, but also exhibits a smaller-sized sea urchin-like structure owing to the CN precursor pretreatment process. The experiment results demonstrate that TCN-M displays an excellent hydrogen production activity of 4.9 mmol g -1 h -1 under visible-light, and its hydrogen production performance can be further enhanced to 14.7 mmol g -1 h -1 after adding 0.5 M K 2 HPO 4 . Thus, this work may supply valuable ideas to further optimize the photocatalytic activity of highly crystalline CN prepared by molten-salt method from the perspective of CN precursor pretreatment. • A highly crystalline carbon nitride with small-sized sea urchin-like structure was successfully prepared. • Large specific surface area and the presence of cyano groups greatly improve the photocatalytic H 2 production activity. • Optimizing the photocatalytic activity of highly crystalline CN from the perspective of CN precursor pretreatment. • A typical H + -reduction cycle can be constructed by introducing K 2 HPO 4 into the reaction system.

Role of Bacterial Community Composition as a Driver of the Small-Sized Phytoplankton Community Structure in a Productive Coastal System

We present here the first detailed description of the seasonal patterns in bacterial community composition (BCC) in shelf waters off the Ría de Vigo (Spain), based on monthly samplings during 2 years. Moreover, we studied the relationship between bacterial and small-sized eukaryotic community composition to identify potential biotic interactions among components of these two communities. Bacterial operational taxonomic unit (OTU) richness and diversity systematically peaked in autumn–winter, likely related to low resource availability during this period. BCC showed seasonal and vertical patterns, with Rhodobacteraceae and Flavobacteriaceae families dominating in surface waters, and SAR11 clade dominating at the base of the photic zone (30 m depth). BCC variability was significantly explained by environmental variables (e.g., temperature of water, solar radiation, or dissolved organic matter). Interestingly, a strong and significant correlation was found between BCC and small-sized eukaryotic community composition (ECC), which suggests that biotic interactions may play a major role as structuring factors of the microbial plankton in this productive area. In addition, co-occurrence network analyses revealed strong and significant, mostly positive, associations between bacteria and small-sized phytoplankton. Positive associations likely result from mutualistic relationships (e.g., between Dinophyceae and Rhodobacteraceae), while some negative correlations suggest antagonistic interactions (e.g., between Pseudo-nitzchia sp. and SAR11). These results support the key role of biotic interactions as structuring factors of the small-sized eukaryotic community, mostly driven by positive associations between small-sized phytoplankton and bacteria.

Design and Simulation of Linear All-Optical Comparator Based on Square-Lattice Photonic Crystals

An optical comparator is an important logic circuit used in digital designs. Photonic crystals are among the platforms for implementing different kinds of gates and logic circuits, and they are structures with alternating refractive indices. In this paper, an optical comparator is designed and simulated based on a square lattice photonic crystal. In the design of this comparator, a small-sized structure is used. The simulation results show that in the proposed comparator, there is a high difference between logical values “0” and “1”, which are defined based on the optical power level. Due to the small size of this comparator and the adequate difference between logical values “0” and “1”, this structure suits photonic integrated circuits with high accuracy. The proposed structure footprint is 149.04 µm2, and the calculated rise time for this circuit is less than 0.4 ps.

Pore structure regulation of hierarchical porous carbon derived from coal tar pitch via pre-oxidation strategy for high-performance supercapacitor

Carbon materials with rational pore structure have attracted tremendous attention in high-performance supercapacitor applications. However, designing and constructing such carbon materials with excellent performances via a simple and low-cost route is still a challenge. Herein, the nitrogen self-doped oxygen-rich hierarchical porous carbons (OTSx-PC) derived from coal tar pitch are constructed via a facile strategy of air pre-oxidation-activation. The air pre-oxidation treatment can effectively regulate the small-sized mesopore structure (2–4 nm) of samples. The optimal OTS350-PC sample exhibits a high specific capacitance of 298 F g−1 at 0.5 A g−1, and delivers a high energy density of 14.9 Wh kg−1 at a power density of 0.15 kW kg−1 with remarkable cycling stability in KOH aqueous electrolyte. This excellent electrochemical performance is attributed to its ultrahigh specific surface area (SSA, 2941 m2 g−1), huge total pore volume (Vt, 1.9 cm3 g−1), rational pore structure and reasonable heteroatom configuration, which ensure sufficient charge storage, rapid electrolyte ions diffusion, as well as the contributed pseudocapacitance. This research not only offers a facile route for high-value utilization of coal tar pitch but also provides the cost-effective and excellent porous carbons for supercapacitor with high performance.

Graphene-layer-coated boron carbide nanosheets with efficient electromagnetic wave absorption

Boron carbide (B4C) is normally known as a structural ceramic with excellent mechanical properties. Herein, the application of graphene-layer-coated B4C nanosheets (B4C@GN NSs) as efficient electromagnetic (EM) wave absorption materials was reported for the first time. B4C@GN NSs grew via the vapor–solid (VS) mechanism and coated with an ultrathin graphene layer through annealing. In addition to its graphene shell, the B4C@GN NSs had a unique small-sized nanosheet structure with a single sheet thickness of less than 50 nm. Concurrently, B4C micro- and nanoparticles were purchased or prepared to compare the morphologies and performances of several kinds of different B4C materials via characterization and analyses. The comparison revealed that the novel B4C@GN NSs possessed a special structure and a unique graphene shell that led to the great improvement in EM wave absorption. With a thickness of 1.19 mm, the B4C@GN NSs exhibited a minimal reflection loss (RLmin) of − 24.6 dB and a broad effective absorption bandwidth of 3.9 GHz. The electronic structure was analyzed by XANES to clarify the mechanism. The above results proved B4C@GN NSs to be an expectant absorber. The development of B4C@GN NSs might lay a theoretical foundation for the functionalization of structural ceramic materials.

Reconfigurable Holographic Metasurface Aided Wideband OFDM Communications Against Beam Squint

The future sixth-generation wireless communications are expected to realize an intelligent network of low powered and high throughput transmissions. In response to such demands, the reconfigurable holographic metasurface (RHS) is evolving into a promising solution owing to its flexible beam steering capability with low power and hardware costs. Unlike traditional phased antenna arrays with independent phase shifters, the RHS can generate desired beams by radiation amplitude control of the reference wave propagating along the metasurface. This so-called holographic interference technique enables an ultra-thin, small-sized planar antenna structure, which is suitable for integrated implementation without any complex phase-shifting or power-division circuits. In this paper, we consider an RHS-aided wideband communication system with an RHS-equipped base station. We aim to maximize the achievable data rate via joint digital beamforming (DBF) and holographic beamforming (HBF). To defeat the beam squint loss brought by the frequency-selective nature, we leverage the additivity of holographic interference patterns to design a novel amplitude control algorithm for solving the HBF subproblem, which contributes to our proposed joint DBF and HBF scheme. Simulation results validate the effectiveness of the proposed scheme against the beam squint issue in terms of the achievable rate.

Research of high-performance harvesting and transport equipment

The question of applying the most progressive technologies of cleaning work of efficient systems of machines is of paramount importance. In solving tasks to ensure the sustainable development of agricultural production, reliable supply of the population of the country, food in food is an important place to strengthen the material and technical base of the agro-industrial complex, its targeted technical re-equipment. In this regard, the goal of the work is to study the rational method of increasing the performance of the screw screw conveyor, allowing you to create a small-sized structure, is an increase in its revolutions. The article provides research in the method of increasing the performance of the screw screw conveyor, allowing you to create a small-sized design by increasing its revolutions. The technology of the work of conveyors-grab trucks was described, the work mechanism was investigated and the disadvantages of work were described, namely, in defective providing the possibility of grain transfer over long distances along the spatial track or complicates the technological scheme. Such an organization of harvesting on the scale of the country involves the creation and implementation of several systems of high-performance cleaning and transport equipment primarily in the main grain areas.

High-concentration Nafion-based hydrogen sensor for fuel-cell electric vehicles

This paper reports the fabrication and characterization of a high-concentration potentiometric hydrogen sensor for fuel-cell vehicle applications. Hydrogen sensors have been mainly developed for detecting hydrogen at concentrations less than the lower explosion limit of 4% in air. However, a wide detection range is required to monitor and control hydrogen concentrations in hydrogen fuel-cell vehicles. We demonstrated a cost-effective and wide detection-range Nafion-based potentiometric hydrogen sensor. The conventional hot-pressing method was used to fabricate a small-sized and multilayer structure comprising a Nafion membrane and Pt-C electrodes. The dependence of the sensor performance on the hydrogen concentration, relative humidity, pressure, and temperature was examined. The fabricated sensor exhibited a response to hydrogen gas in a concentration range of 20–99.99% and a high performance reliability against environmental variations. The simple structure and reliable operation of the sensor make it promising for practical applications.

Electrochemical properties of Co-doped rod-like Li4Ti4.92Co0.08O12 as anode material for lithium-ion batteries

In this study, the Li4Ti5−xCoxO12 anode material was synthesized by hydrothermal method using Ti(OC4H9)4, LiOH·H2O and CoAc2 as raw materials. When the doping molar amount of Co is 0.08, the prepared Li4Ti4.92Co0.08O12 anode material has good electrochemical performance. The material sample is a small-sized and rod-like structure (about 100–400 nm), and the rod-like structures of different sizes are sparsely arranged to successfully improve the discharge specific capacity. Doping Co2+ makes the 3d orbit of pure phase Li4Ti5O12 have electrons, which increases the electronic conductivity of the material. In the rate performance test, the discharge specific capacity is as high as 256.9 mAh g−1 at a current density of 20 mA g−1. In the cycle performance test, the specific capacity of Li4Ti4.92Co0.08O12 anode material was stable at 156.5 mAh g−1 at the current density is 1 A g−1 after 1000 cycles, and the capacity retention rate was as high as 92.17%.

The effect of calcination atmosphere upon the photocatalytic performance of Au-La2O3/TiO2 for hydrogen production from formic acid

A simple modified sol-gel method by calcinating titanium dioxide precursor with gold and lanthanum in heat treatment under H2/CO2 atmosphere has been proposed to prepare highly photocatalytic Au-La2O3/TiO2 (ALT) hybrid. Characterization results show that gold nanoparticles with small particle size are embedded in a nearly homogeneous component, which may induce a strong interaction of La and Au co-doping to obtain an appropriately modified bandgap structure and extend the absorption edge to visible light region. The formation of La2O2CO3 on the surface could facilitate to the basicity optimization of the photocatalyst and contribute to the CH bond cleavage in HCOO- to release H2 and CO2 from formic acid (FA). The large surface area and small-sized mesopores structure could provide more active sites for the adsorption of reactant molecules and improve the photocatalytic activity. Benefiting from these positive effects, the ALT photocatalyst calcinating in H2/CO2 demonstrated a great potential in FA photocatalytic decomposition under simulated sunlight irradiation and produced an optimal H2 generation rate of 178.4μmolgcat−1h−1 (14.9mmolgAu−1h−1), which was approximately 1.3, 1.9 and 2.6 times higher than the same catalysts calcinating in H2, CO2, and N2, respectively.

A structure optimization framework for feed-forward neural networks using sparse representation

Traditionally, optimizing the structure of a feed-forward neural-network is time-consuming and it needs to balance the trade-off between the network size and network performance. In this paper, a sparse-representation based framework, termed SRS, is introduced to generate a small-sized network structure without compromising the network performance. Based on the forward selection strategy, the SRS framework selects significant elements (weights or hidden neurons) from the initial network that minimize the residual output error. The main advantage of the SRS framework is that it is able to optimize the network structure and training performance simultaneously. As a result, the training error is reduced while the number of selected elements increases. The efficiency and robustness of the SRS framework are evaluated based on several benchmark datasets. Experimental results indicate that the SRS framework performs favourably compared to alternative structure optimization algorithms.

Realization of polarization-angle-independent fishnet-based waveguide metamaterial comprised of octagon shaped resonators with sensor and absorber applications

A new fishnet-based waveguide metamaterial structure for the microwave region is introduced and investigated both numerically and experimentally. The proposed model is designed and fabricated on both sides of the substrate and exhibits strong metamaterial behavior (such as negative material parameters: i.e. negative permittivity, negative permeability, and negative index of refraction) at the resonance. Only one single slab is used in the simulation and experiment which provides a reduction in the number of the required samples with respect to its free-space and/or waveguide counterparts. This means that a small-sized metamaterial structure is simulated, measured, and characterized by placing the sample in the waveguide. The effective medium theory is employed for the characterization of the structure and the left-handed region is identified. The measured results are in good agreement with the simulated ones which show that the proposed structure operates well in terms of metamaterial behavior and can be used in waveguide miniaturization and waveguide-based applications such as antennas, filters, sensors, absorbers, imaging systems, and so on. To validate this claim, sensor and absorber applications are selected and the simulation results show that the proposed sensor and absorbers devices operate well under the defined conditions.

Ka 대역 다중모드 모노펄스 추적 시스템을 위한 한 쌍의 슬롯(Slot)을 갖는 모드커플러 설계

OTM(On-The-Move) 위성통신 시스템은 차량에 탑재되어 고속 주행하거나 요동이 심한 지역을 주행하면서 위성 통신 링크를 안정적으로 유지하여야 한다. 따라서 열악한 환경에서도 정밀 추적이 가능하고, 차량에 탑재할 수 있도록 소형/경량화된 위성 추적 시스템이 필요하다. 2개의 슬롯(slot)으로 구성된 단일 모드 커플러를 사용하여, 원형 편파 특성을 이용하여 하나의 물리적 채널로 상하, 좌우 2개의 차신호를 동시에 비콘 수신기까지 전달하는 방안을 제안하고, 측정된 추적 오차신호를 제시한다. The main mission of OTM(On-The-Move) satellite communication system is to provide satellite communication service while moving on a vehicle. So it should have a capability to maintain a reliable communication channel when it travels at high speeds or in a severe fluctuation region. This paper presents a small-sized multi-mode monopulse structure applicable to OTM satellite communication system which has only single mode-coupler with a pair of slot using a feature of circular polarized received signal. And tracking error signal is defined using fundamental and high-order modes.

Spatial and temporal variability of small-sized copepod assemblages in a shallow semi-enclosed embayment (Kalloni Gulf, NE Mediterranean Sea)

The small-sized copepod community structure (&lt;1 mm) and its response to environmental variability was examined during an annual cycle in Kalloni Gulf, a semi-enclosed coastal system in the NE Aegean Sea. Α 90 µm net was used in order to adequately sample the smaller copepod fractions. In the copepod ecology the spatial patterns dominated over the seasonal. Total copepod abundance increased towards the inner gulf area while diversity indices followed the opposite trend. The inner gulf copepod assemblage area was affected by the increasing magnitude of eutrophication, characterized by high abundance values, low species richness and dominance of a single species (e.g.Oithona nana). A clear seasonal succession of species was observed, ordered by temperature, salinity, chlorophyll a, heterotrophic bacterial biomass, organic and inorganic nutrients. Freshwater inputs and the subsequent nutrient inflow was a dominant phenomenon enhancing copepod production and negatively affecting the biodiversity of the assemblage. The great contribution of copepod larval stages in the total community and their year-round presence indicate the continuous production of copepods during the annual cycle, highlight the importance of the smaller size fraction and encourage the use of finer mesh-size nets when assessing the structure and dynamics of copepod communities.

Wet-texturing process for a thin crystalline silicon solar cell at low cost with high efficiency

In the wet-texturing process, a smaller etch depth of 8 µm was established on each side of the thin silicon wafer. Formation of a very small size (1–3 µm) pyramidal structure was confirmed on a thin c-Si surface through the use of SEM micrographs. For this silicon surface with small pyramidal structures, a surface reflectance of 15.14% was observed. Saw damage removal was employed for the second and the third sets of silicon wafers in a NaOH (8 wt%) solution, and the wafers were then textured in a mixture of NaOH (1.5 wt%), de-ionized water and Isopropyl alcohol (IPA, 6–8 wt%) at 80 °C for 18 min and 24 min, respectively. In this process, the scraped depths were 16 and 26 µm on each side of the second and the third sets of silicon wafers, and the pyramidal sizes were 4–9 µm and 9–12 µm respectively. We found that the reflectances of these sets of wafers were 14.98% and 14.78%, respectively. Our novel approach of ultrasonic cleaning, hot de-ionized water treatment, and texturing for thin c-Si wafers yielded small-sized (1–3 µm) uniform pyramidal structure that were stable and suitable for metalized screen printing. Even though the reflectance was high for the first set of wafers the illuminated current-voltage (LIV) measurements confirmed the wafers’ superiority over the conventional textured c-Si solar cells in terms of the open-circuit voltage and the fill factor. The small-size pyramidal-structured thin single-crystalline silicon solar cells showed a 17.9% efficiency. Since no NaOH solution was used for saw damage removal in the first set of silicon wafers, the production cost for commercial production of large-area single-crystalline silicon solar cells was reduced by nearly 20%.

Statistical characterization of vertical poly-Si channel using charge pumping technique for 3D flash memory optimization

We analyzed the charge pumping signals in ultra-scaled 3D vertical devices.Statistical analysis has been used to characteristic the variability of poly-Si channel.The quality of bottom and top junctions with different process has been presented.Different poly-Si formations and hole sizes have been investigated.Different annealing conditions have been carried out for optimization of the channel of 3D flash memory. Poly silicon has been used as the vertical channel material in 3D devices for future generations of NAND flash memory. Improving the read current and reducing its variations in the small-sized single-hole structure are among the critical challenges, which require understanding and characterizing interface states and bulk defects in the vertical 3D poly-Si channel. In this paper, we analyzed the charge pumping signals in ultra-scaled 3D vertical devices and characterized the poly-Si channel by using statistical analysis. Devices with different poly-Si formations, hole sizes and annealing conditions have been investigated, in order to optimize the 3D device.

The design and analysis of beam-membrane structure sensors for micro-pressure measurement

This paper reports the design and analysis of a type of piezoresistive pressure sensor for micro-pressure measurement with a cross beam-membrane (CBM) structure. This new silicon substrate-based sensor has the advantages of a miniature structure and high sensitivity, linearity, and accuracy. By using the finite element method to analyze the stress distribution of the new structure and subsequently deducing the relationship between structural dimensions and mechanical performances, equations used to determine the CBM structure are established. Based on the CBM model and our stress and deflections equations, sensor fabrication is then performed on the silicon wafer via a process including anisotropy chemical etching and inductively coupled plasma. The structure's merits, such as linearity, sensitivity, and repeatability, have been investigated under the pressure of 5 kPa. Our results show that the precision of these equations is ±0.19%FS, indicating that this new small-sized structure offers easy preparation, high sensitivity, and high accuracy for micro-pressure measurement.

Application of micro- and nanoprobes to the analysis of small-sized 3D materials, nanosystems, and nanoobjects

The basic physics behind the interaction of ions with solid-state matter is discussed, with an emphasis on the formation of interaction products between the ions and target atoms. Processes covering modification of high-resistance materials for use in small-sized 3D structure technology are described. Current trends in and problems facing the development of the scanning nuclear microprobe (SNMP) are reviewed. The application of slow positrons to diagnosing materials is examined and the techniques of positron microscopy and microprobing are presented. The potential of near-field microwave microscopy for diagnosing superconducting ceramics and of microwave microscopy for nanotechnology applications are assessed. The examples given include the use of micro- and nanoprobes to analyze nanoobjects (such as green algae cells with 3D-distributed microelements, etc.), to develop the topological aspects of integrated microcircuits in nanoelectronics, and some other applications. The role of iron in pathogenesis of Parkinson's disease is highlighted, the latter being the subject of research in neurochemistry.