bluuebunny/crossref_metadata_2025 huggingface dataset:
The Effects of Exercise Training on Glucose Homeostasis and Muscle Metabolism in Type 1 Diabetic Female Mice
Authors: O’Neill Caitlin C. , Locke Erica J. , Sipf Darren A. , Thompson Jack H. , Drebushenko Erin K. , Berger Nathan S. , Segich Brooke S. , Kolwicz Stephen C.
Published: October 2022

Although exercise training is an important recommendation for the management of type 1 diabetes (T1D), most of the available research studies predominantly focus on male subjects. Given the importance of sex as a biological variable, additional studies are required to improve the knowledge gap regarding sex differences in T1D research. Therefore, the purpose of this study was to examine the role of exercise training in mediating changes in glucose homeostasis and skeletal muscle metabolism in T1D female mice. Female mice were injected with streptozotocin (STZ) to induce T1D. Two weeks after STZ injection, control (CON) and STZ mice were exercise trained on a treadmill for 4 weeks. Aerobic exercise training failed to improve glucose tolerance, prevent the decrease in body weight and adipose tissue mass, or attenuate muscle atrophy in T1D female mice. However, insulin sensitivity was improved in T1D female mice after exercise training. Aerobic exercise training maintained skeletal muscle triglyceride content but did not prevent depletion of skeletal muscle or liver glycogen in T1D mice. Gene expression analysis suggested that T1D resulted in decreased glucose transport, decreased ketone body oxidation, and increased fatty acid metabolism in the skeletal muscle, which was not altered by exercise training. These data demonstrate that 4 weeks of aerobic exercise training of a moderate intensity is insufficient to counteract the negative effects of T1D in female mice, but does lead to an improvement in insulin sensitivity.
The Role of Kynurenine and Its Metabolites in Comorbid Chronic Pain and Depression
Authors: Athnaiel Onella , Ong Charmaine , Knezevic Nebojsa Nick
Published: October 2022

Chronic pain and depression affect millions of people worldwide, and their comorbidity tends to exacerbate the severity of each individual condition. Intersecting brain regions and molecular pathways could probably explain the unique yet complex bidirectional relationship between these two disorders. Recent studies have found that inflammatory reactions, frequently identified in both chronic pain and depression, stimulate certain enzymes in the kynurenine pathway, while concurrently suppressing others. Kynurenine, a major tryptophan derivative, and its metabolites have been implicated in several inflammation-associated pain syndromes and depressive mood disorders. Due to inflammation, 95% of tryptophan is metabolized via the kynurenine pathway, which drives the reaction towards the production of metabolites that have distinct roles in the pathophysiology of these disorders. Diminished levels of the neuroprotective metabolite, kynurenic acid (KYNA), and elevated levels of the neurotoxic metabolite, quinolinic acid (QUIN), have been frequently identified in human patients formally diagnosed with these disorders, as well as animal models commonly used in medical research. This review not only explores the epidemiology of comorbid chronic pain and depression, but also highlights the involvement of kynurenine and its metabolites, specifically KYNA and QUIN, in these pervasive conditions.
Enhancing the Production of the Phenolic Extracts of Asparagus Using an Advanced Green Process
Authors: López-Salas Lucía , Borrás-Linares Isabel , Quirantes-Piné Rosa , Emanuelli Tatiana , Segura-Carretero Antonio , Lozano-Sánchez Jesús
Published: October 2022

Asparagus officinalis L. is a common vegetable widely consumed due to its high consumer acceptance. In addition to its flavor, green asparagus contains a high amount of bioactive compounds with health-promoting effects. In this sense, the growing concern of the public health system to promote a diet with a higher consumption of vegetables makes research on phytochemicals from this food of interest. In order to study the content of bioactive compounds from plant matrices, the combination of advanced extraction and analytical techniques within the context of green chemistry is an indispensable working model in today’s research. In the present experimental work, the composition of the phytochemicals of green asparagus from the Protected Geographical Indication (PGI) located in Huétor Tájar, Granada (Spain), was evaluated by environmentally friendly extraction techniques. In order to carry out this work, the recovery of bioactive compounds was evaluated by pressurized liquid extraction (PLE) using GRAS (Generally Recognized As Safe) solvents (mixtures of water and ethanol). The extraction was optimized using a Response Surface Methodology (RSM) based on a 24 factorial Central Composite Design (CCD). The experimental model was followed by high-performance liquid chromatography coupled to electrospray ionization time-of-flight mass spectrometry (HPLC–ESI-TOF-MS) analytical methodology for a comprehensive characterization. The optimized methodology was compared with conventional solid–liquid extraction protocols using ethanol and water. The results highlighted the potential of advanced PLE techniques compared to conventional systems for the recovery of green asparagus phytochemicals. Moreover, the analytical characterization allowed the identification and quantitation of major phenolic compounds belonging to phenolic acids and flavonoids families. Therefore, an easy, fast, and novel methodology to optimize the extraction of bioactive compounds from green asparagus has been optimized, using Green and GRAS methodology, which enables a better understanding of the bioactive composition of this widely consumed food.
Plasma Metabolomic Analysis Reveals the Relationship between Immune Function and Metabolic Changes in Holstein Peripartum Dairy Cows
Authors: Yang Zhuo , Luo Fang , Liu Guolin , Luo Zhengzhong , Ma Sijia , Gao Hang , He Hailong , Tao Jinzhong
Published: October 2022

Dairy cows undergo dynamic physiological changes from late gestation to early lactation, including metabolic changes and immune dysfunction. The aim of this study was to investigate the relationship between immune function and metabolic changes in peripartum dairy cows. Fifteen healthy Holstein dairy cows were enrolled 14 days prior to parturition, and plasma was collected on day −7, 0, 7, and 21 relative to calving. Plasma non-esterified fatty acids (NEFAs), glucose, β-hydroxybutyric acid (BHBA), immunoglobulin G (IgG), tumor necrosis factor alpha (TNF-α), and interleukin-2 levels were measured, and metabolic profiles were determined using ultra-high-performance liquid chromatography–quadrupole time-of-flight mass spectrometry. The data were analyzed using Tukey–Kramer adjustment for multiple comparisons, and multivariate and univariate statistical analyses were performed to screen for differential metabolites. The results showed that the concentrations of NEFAs, glucose, BHBA, and TNF-α in the plasma significantly increased and concentrations of IgG and interleukin-2 in plasma significantly decreased from −7 d to the calving day (p < 0.05). Additionally, the concentrations of glucose, IgG, and TNF-α significantly decreased from 0 to +7 d, and concentrations of NEFAs decreased significantly from +7 to +21 d (p < 0.05). The following six primary metabolic pathways were identified in all time point comparisons, and L-glutamate, linoleic acid, taurine, and L-tryptophan were involved in these major metabolic pathways. Correlation and pathway analyses indicated that a negative energy balance during the transition period adversely affects immune responses in cows, and L-tryptophan exerts immunomodulatory effects through the Trp-Kyn pathway, resulting in depletion of Trp and elevation of Kyn.
COQ8A-Ataxia as a Manifestation of Primary Coenzyme Q Deficiency
Authors: Paprocka Justyna , Nowak Magdalena , Chuchra Piotr , Śmigiel Robert
Published: October 2022

COQ8A-ataxia is a mitochondrial disease in which a defect in coenzyme Q10 synthesis leads to dysfunction of the respiratory chain. The disease is usually present as childhood-onset progressive ataxia with developmental regression and cerebellar atrophy. However, due to variable phenotype, it may be hard to distinguish from other mitochondrial diseases and a wide spectrum of childhood-onset cerebellar ataxia. COQ8A-ataxia is a potentially treatable condition with the supplementation of coenzyme Q10 as a main therapy; however, even 50% may not respond to the treatment. In this study we review the clinical manifestation and management of COQ8A-ataxia, focusing on current knowledge of coenzyme Q10 supplementation and approach to further therapies. Moreover, the case of a 22-month-old girl with cerebellar ataxia and developmental regression will be presented.
Paeonol Ameliorates Ulcerative Colitis in Mice by Modulating the Gut Microbiota and Metabolites
Authors: Zheng Jiahui , Li Huan , Zhang Pei , Yue Shijun , Zhai Bingtao , Zou Junbo , Cheng Jiangxue , Zhao Chongbo , Guo Dongyan , Wang Jing
Published: October 2022

Ulcerative colitis (UC) is a chronic recurrent inflammatory disease of the gastrointestinal tract. Recent studies demonstrate that the phenolic tannin paeonol (Pae) attenuates UC in mouse models by downregulating inflammatory factors. However, its molecular mechanism for UC treatment has not been explored from the perspective of the gut microbiota and metabolomics. In this study, we investigated the effects of Pae on colonic inflammation, intestinal microbiota and fecal metabolites in 3% dextran sodium sulfate (DSS) induced BALB/c UC mice. Pae significantly improved the clinical index, relieved colonic damage, reduced cytokine levels, and restored the integrity of the intestinal epithelial barrier in UC mice. In addition, Pae increased the abundance of gut microbiota, partially reversed the disturbance of intestinal biota composition, including Lactobacillus and Bacteroides, and regulated metabolite levels, such as bile acid (BA) and short-chain fatty acid (SCFA). In conclusion, our study provides new insight on Pae remission of UC.
Simulation of an Aeronautical Product Assembly Process Driven by a Metrology Aided Virtual Approach
Authors: Kortaberria Gorka , Mutilba Unai , Eguskiza Jon , Martins Joel
Published: October 2022

Major aircraft manufacturers are expecting the commercial aircraft market to overcome the pre-COVID levels by 2025, which demands an increase in the production rate. However, aeronautical product assembly processes are still mainly manually performed with a low level of automation. Moreover, the current industry digitalization trend offers the possibility to develop faster, smarter and more flexible manufacturing processes, aiming at a higher production rate and product customization. Here, the integration of metrology within the manufacturing processes offers the possibility to supply reliable data to constantly adjust the assembly process parameters aiming at zero-defect, more digital and a higher level of automation manufacturing processes. In this context, this article introduces the virtual metrology as an assistant of the assembly process of the Advanced Rear-End fuselage component. It describes how the assembly process CADmodel is used by simulation tools to design, set up and perform the virtual commissioning of the new metrology-driven assembly methods, moving from a dedicated tooling approach to a more flexible and reconfigurable metrology-aided design. Preliminary results show that portable metrology solutions are fit-to-purpose even for hardly accessible geometries and fulfil the current accuracy demands. Moreover, the simulation environment ensures a user-friendly assembly process interaction providing further set-up time reduction.
A High-Throughput and Uniform Amplification Method for Cell Spheroids
Authors: Liu Liyuan , Liu Haixia , Huang Xiaowen , Liu Xiaoli , Zheng Chengyun
Published: October 2022

Cell culture is an important life science technology. Compared with the traditional two-dimensional cell culture, three-dimensional cell culture can simulate the natural environment and structure specificity of cell growth in vivo. As such, it has become a research hotspot. The existing three-dimensional cell culture techniques include the hanging drop method, spinner flask method, etc., making it difficult to ensure uniform morphology of the obtained cell spheroids while performing high-throughput. Here, we report a method for amplifying cell spheroids with the advantages of quickly enlarging the culture scale and obtaining cell spheroids with uniform morphology and a survival rate of over 95%. Technically, it is easy to operate and convenient to change substances. These results indicate that this method has the potential to become a promising approach for cell–cell, cell–stroma, cell–organ mutual interaction research, tissue engineering, and anti-cancer drug screening.
Investigation of an Output Voltage Harmonic Suppression Strategy of a Power Quality Control Device for the High-End Manufacturing Industry
Authors: Wan Chengkuan , Li Kai , Xu Lin , Xiong Chao , Wang Lingang , Tang Hao
Published: October 2022

Due to the influence of nonlinear loads, power quality control devices under the traditional double closed-loop control strategy suffer from a large output voltage harmonic distortion rate and a slow harmonic suppression response and cannot meet the high-quality power supply requirements of high-end manufacturing. A compound control strategy based on voltage feedback and current feed-forward is proposed to solve the voltage quality problem under a nonlinear load. Firstly, based on the mathematical model of power quality control device, the working principle and voltage current coupling relationship are analyzed. Then, an output voltage compound control strategy based on feed-forward and feedback is proposed, and the harmonic suppression mechanisms are deduced and analyzed. Finally, simulation and experimental results are presented to show that, compared with the traditional double closed-loop control strategy, the harmonic suppression effect of the composite control strategy proposed in this paper can be increased by 2.2%, and the response time is decreased to 100 ms.
Microfluidic Synthesis, Doping Strategy, and Optoelectronic Applications of Nanostructured Halide Perovskite Materials
Authors: Zou Shuangyang , Zhao Xiaoan , Ouyang Wenze , Xu Shenghua
Published: October 2022

Halide perovskites are increasingly exploited as semiconducting materials in diverse optoelectronic applications, including light emitters, photodetectors, and solar cells. The halide perovskite can be easily processed in solution, making microfluidic synthesis possible. This review introduces perovskite nanostructures based on micron fluidic channels in chemical reactions. We also briefly discuss and summarize several advantages of microfluidics, recent progress of doping strategies, and optoelectronic applications of light-sensitive nanostructured perovskite materials. The perspective of microfluidic synthesis of halide perovskite on optoelectronic applications and possible challenges are presented.
Prediction of Surface Roughness in Gas-Solid Two-Phase Abrasive Flow Machining Based on Multivariate Linear Equation
Authors: Wang Wenhua , Yuan Wei , Yu Jie , Guo Qianjian , Chen Shutong , Yang Xianhai , Cong Jianchen
Published: October 2022

The main purpose of this study is to explore a surface roughness prediction model of Gas-Solid Two-Phase Abrasive Flow Machining. In order to achieve the above purpose, an orthogonal experiment was carried out. Q235 steel as processing material and white corundum with different particle sizes as abrasive particles were used in the experiment. Shape and spindle speed were the main reference factors. The range method and factor trend graph are used to comprehensively analyze the experimental results of different processing stages of the detection point, and the optimal parameter combination of A3B2C1D2 was obtained. According to the experimental results, a multiple linear regression equation was established to predict the surface roughness, and the experimental results were solved and significantly analyzed by software to obtain a highly reliable prediction model. Through experiments, modeling and verification, it is known that the maximum error between the obtained model and the actual value is 0.339 μm and the average error is 0.00844 μm, which can better predict the surface roughness of the gas-solid two-phase flow abrasive pool.
Comparative Study of Gravimetric Humidity Sensor Platforms Based on CMUT and QCM
Authors: Zheng Zhou , Zhang Guodong , Wang Xiaomin , Kong Xu
Published: October 2022

Humidity sensors with comprehensive performance are of great interest for industrial and environmental applications. Most sensors, however, have to compromise on at least one characteristic such as sensitivity, response speed, and linearity. This paper reports a gravimetric humidity sensor based on a capacitive micromachined ultrasonic transducer (CMUT) with exceptional all-around performance, and presents a side-by-side comparative investigation of two types of gravimetric humidity sensors for a better understanding of their characteristics and sensing mechanisms. For these purposes, a circular CMUT and a quartz crystal microbalance (QCM) with a resonance frequency of 10 MHz were designed and fabricated. Poly(vinyl alcohol) (PVA) was employed as the humidity sensing layer for its hydrophilicity and ease of film formation. The electrical properties of the sensors, including the electrical input impedances and quality factors, were characterized by a vector network analyzer. The relative humidity (RH) sensing performance of the sensors was evaluated and compared from RH levels of 11% to 97%. Both sensors exhibited good repeatability and low hysteresis. The unique microscale resonant structure of the CMUT humidity sensor contributed to a high sensitivity of 2.01 kHz/%RH, short response and recovery times of 8 s and 3 s, respectively, and excellent linearity (R2 = 0.973), which were far superior to their QCM counterparts. The underlying mechanism was revealed and discussed.
Contactless Discharge-Driven Method for Separation of Oil-Water Mixtures
Authors: Tang Qiang , Cui Xiaxia , Hu Zhibin , Lu Shaotian , Wang Chengjun , Tang Jau
Published: October 2022

Oil–water separation technology has potential applications in wastewater treatment, petroleum refining and edible oil processing. As the ultimate means in oil-water treatment, electrostatic coalescence technology has been widely used in oil fields and refineries. However, the technology has many problems, such as complex processes, electrode corrosion, and the inability to treat high-water-cut crude oil emulsions. Here, we propose a contactless method of oil-water separation by corona discharge. With corona discharge of a needle–plate electrode configuration, the oil droplet diffuses to the ITO glass surface and the water droplet oscillates at the edge of the PET film. Here, such droplet behaviors are described in detail. Based on the motion behavior of the oil and water droplet, we designed an efficient oil-water separation device. After the oil-water mixture passes through the device, the oil content in the oil region can reach 99.25% with a voltage of 8 kV. In addition, the separation speed of the oil-water mixture can also be adjusted by varying the corona discharge voltage. This paper presents a simple and innovative method for oil-water separation.
Femtosecond Laser-Assisted Ophthalmic Surgery: From Laser Fundamentals to Clinical Applications
Authors: Yan Quan , Han Bing , Ma Zhuo-Chen
Published: October 2022

Femtosecond laser (FSL) technology has created an evolution in ophthalmic surgery in the last few decades. With the advantage of high precision, accuracy, and safety, FSLs have helped surgeons overcome surgical limits in refractive surgery, corneal surgery, and cataract surgery. They also open new avenues in ophthalmic areas that are not yet explored. This review focuses on the fundamentals of FSLs, the advantages in interaction between FSLs and tissues, and typical clinical applications of FSLs in ophthalmology. With the rapid progress that has been made in the state of the art research on FSL technologies, their applications in ophthalmic surgery may soon undergo a booming development.
Comparative Study and Simulation of Capacitive Sensors in Microfluidic Channels for Sensitive Red Blood Cell Detection
Authors: Hu Wei , Wu Bingxing , Srivastava Soumya K. , Ay Suat Utku
Published: October 2022

Microfluidics provides an indispensable platform for combining analytical operations such as sample preparation, mixing, separation/enrichment, and detection onto a single compact platform, defined as a lab-on-a-chip (LOC) device with applicability in biomedical and life science applications. Due to its ease of integration, 1D interdigital capacitive (IDC) sensors have been used in microfluidic platforms to detect particles of interest. This paper presents a comparative study on the use of capacitive sensors for microfluidic devices to detect bioparticles, more specifically red blood cells (RBCs). The detection sensitivities of 1D, 2D, and 3D capacitive sensors were determined by simulation using COMSOL Multiphysics® v5.5. A water-filled 25 μm × 25 μm PDMS microfluidic channel was used with different sizes (5–10 μm) of red blood cells passing across the capacitive sensor regions. The conformal mapping was used for translating the 1D IDC sensor dimensions into equivalent 2D/3D parallel plate capacitance (PPC) sensor dimensions, creating similar absolute sensor capacitance. The detection sensitivity of each capacitive sensor is determined, and a new 3D PPC sensor structure was proposed to improve the sensitivity for high-resolution RBC detection in microfluidic channels. Proposed 2D and 3D sensors provide a 3× to 20× improvement in sensitivity compared to the standard 1D IDC structures, achieving a 100 aF capacitance difference when a healthy RBC passes in the structure.
High-Gain Wideband Circularly Polarised Fabry–Perot Resonator Array Antenna Using a Single-Layered Pixelated PRS for Millimetre-Wave Applications
Authors: Melouki Noureddine , Hocini Abdesselam , Fegriche Fatima Zahra , PourMohammadi Peyman , Naseri Hassan , Iqbal Amjad , Denidni Tayeb A.
Published: October 2022

In this paper, a wideband and high-gain circular polarised Fabry–Perot Resonator Antenna (FPRA) with a single partially reflective surface (PRS) layer is automatically generated and optimised using a VBA-based interface system between CST Microwave studio and Matlab. The proposed PRS layer is a promising superstrate for wideband and high-gain FP resonator antennas due to its relatively high reflection coefficient magnitude and positive phase gradient, which resemble that of the optimum PRS over the relevant frequency band. The circular polarisation was achieved using a sequential feeding network for a 2 × 2 array air-gapped slot-coupled elliptical patch antenna. The proposed design achieved an impedance bandwidth of 48.58% (15.3 GHz) ranging from 23.84 GHz to 39.14 GHz, and the −3 dB gain bandwidth was 22.42% (6.25 GHz) from 24.75 to 31 GHz, with a peak gain of 17.12 dB at 29 GHz, and an axial ratio bandwidth of 21.75% (6.2 GHz). In addition, the achieved radiation efficiency was 90%. Consistent and almost invariant radiation patterns are achieved over the millimetre-wave frequency band of interest. The experimental and simulated results are in good agreement, justifying the feasibility of the proposed design as a high-gain and wideband FP resonator array antenna for Mm-wave applications.
The Effect of Non-Uniform Magnetic Field on the Efficiency of Mixing in Droplet-Based Microfluidics: A Numerical Investigation
Authors: Rezaeian Masoud , Nouri Moein , Hassani-Gangaraj Mojtaba , Shamloo Amir , Nasiri Rohollah
Published: October 2022

Achieving high efficiency and throughput in droplet-based mixing over a small characteristic length, such as microfluidic channels, is one of the crucial parameters in Lab-on-a-Chip (LOC) applications. One solution to achieve efficient mixing is to use active mixers in which an external power source is utilized to mix two fluids. One of these active methods is magnetic micromixers using ferrofluid. In this technique, magnetic nanoparticles are used to make one phase responsive to magnetic force, and then by applying a magnetic field, two fluid phases, one of which is magneto-responsive, will sufficiently mix. In this study, we investigated the effect of the magnetic field’s characteristics on the efficiency of the mixing process inside droplets. When different concentrations of ferrofluids are affected by a constant magnetic field, there is no significant change in mixing efficiency. As the magnetic field intensifies, the magnetic force makes the circulation flow inside the droplet asymmetric, leading to chaotic advection, which creates a flow that increases the mixing efficiency. The results show that the use of magnetic fields is an effective method to enhance the mixing efficiency within droplets, and the efficiency of mixing increases from 65.4 to 86.1% by increasing the magnetic field intensity from 0 to 90 mT. Besides that, the effect of ferrofluid’s concentration on the mixing efficiency is studied. It is shown that when the concentration of the ferrofluid changes from 0 to 0.6 mol/m3, the mixing efficiency increases considerably. It is also shown that by changing the intensity of the magnetic field, the mixing efficiency increases by about 11%.
Design of Compact and Broadband Polarization Beam Splitters Based on Surface Plasmonic Resonance in Photonic Crystal Fibers
Authors: Mei Chao , Wu Yuan , Yuan Jinhui , Qiu Shi , Zhou Xian
Published: October 2022

In this work, a polarization beam splitter (PBS) based on surface plasmonic resonance is proposed and realized in a designed photonic crystal fiber (PCF). The PCF consists of two kinds of air holes with different diameters. Two solid silica cores near the center of the PCF are established by removing the cladding air holes. A gold film is plated at the external surface of the central air hole of the PCF to excite the surface plasmonic resonance. In order to minimize the length and improve the operation bandwidth of the PBS, the influences of the transversal structural parameters of the PCF are investigated in the context of both X and Y polarization beams. It was found that a 123.6-μm-long PBS with an operation bandwidth of 314 nm could be realized after the global optimization of five structural parameters. The proposed PBS may have potential applications in micro-/nano-optical systems for sensing and communications.
Development of LCEs with 100% Azobenzene Moieties: Thermo-Mechanical Phenomena and Behaviors
Authors: Sagnelli Domenico , Rippa Massimo , D’Avino Amalia , Vestri Ambra , Marchesano Valentina , Petti Lucia
Published: October 2022

Azobenzene is one of the most investigated photo-responsive liquid crystalline molecules. It can isomerize between two different isoforms, trans (E) and cis (Z) configurations, when stimulated by light. It is used as a molecular engine in photo-mobile materials (PMPs). The use of liquid crystals (LCs) as building blocks enhances the mechanical properties of the PMPs. It is not easy to obtain PMPs with monodomain configurations when the LCs are 100% azobenzene. In this work, we studied three LC mixtures, describing the thermo/mechanical phenomena that regulate the actuation of such materials. The nematic temperature of the LC elastomers was measured and the PMPs carefully characterized for their bending and speed capability. Our finding suggests that the ratio between linear and cross-linker monomer greatly influences the nematic temperature of the mixture. Furthermore, 100% azobenzene materials polymerized using dicumyl peroxide can be useful to design polarization-selective switches.
Periodic Structural Defects in Graphene Sheets Engineered via Electron Irradiation
Authors: Melchioni Nicola , Fabbri Filippo , Tredicucci Alessandro , Bianco Federica
Published: October 2022

Artificially-induced defects in the lattice of graphene are a powerful tool for engineering the properties of the crystal, especially if organized in highly-ordered structures such as periodic arrays. A method to deterministically induce defects in graphene is to irradiate the crystal with low-energy (<20 keV) electrons delivered by a scanning electron microscope. However, the nanometric precision granted by the focused beam can be hindered by the pattern irradiation itself due to the small lateral separation among the elements, which can prevent the generation of sharp features. An accurate analysis of the achievable resolution is thus essential for practical applications. To this end, we investigated patterns generated by low-energy electron irradiation combining atomic force microscopy and micro-Raman spectroscopy measurements. We proved that it is possible to create well-defined periodic patterns with precision of a few tens of nanometers. We found that the defected lines are influenced by electrons back-scattered by the substrate, which limit the achievable resolution. We provided a model that takes into account such substrate effects. The findings of our study allow the design and easily accessible fabrication of graphene devices featuring complex defect engineering, with a remarkable impact on technologies exploiting the increased surface reactivity.
A Fully Integrated Low-Dropout Regulator with Improved Load Regulation and Transient Responses
Authors: Hu Chenkai , Chen Zhizhi , Ni Shenglan , Wang Qian , Li Xi , Chen Houpeng , Song Zhitang
Published: October 2022

A fully integrated low-dropout (LDO) regulator with improved load regulation and transient responses in 40 nm technology is presented in this paper. Combining adjustable threshold push–pull stage (ATPS) and master–slave power transistors topology, the proposed LDO maintains a three-stage structure within the full load range. The proposed structure ensures the steady-state performance of LDO and achieves 0.017 mV/mA load regulation. The ATPS consumes little quiescent current at light load current condition, and the turn-on threshold of the ATPS can be adjusted by a current source. Once the value of current source is set, the turn-on threshold is also determined. A benefit of the proposed structure is that the LDO can be stable from 0 to 100 mA load current with a maximum 100 pF parasitic load capacitance and a 0.7 pF compensation capacitor. It also shows good figure of merit (FOM) without an extra transient enhanced circuit. For the maximum 100 mA load transient with 100 ns edge time, the undershoot and overshoot are less than 33 mV. The dropout voltage of the regulator is 200 mV with input voltage of 1.1 V. The total current consumption of the LDO was 24.6 μA at no load.
Highly Efficient Four-Rod Pumping Approach for the Most Stable Solar Laser Emission
Authors: Catela Miguel , Liang Dawei , Vistas Cláudia R. , Garcia Dário , Costa Hugo , Tibúrcio Bruno D. , Almeida Joana
Published: October 2022

We report a significant numerical improvement in multi-rod laser efficiency, with an enhanced solar tracking error compensation capacity for a heliostat-parabolic system. The solar laser head was composed of a fused silica conical lens and a single conical pump cavity ensuring multiple passes through four 4.55 mm diameter, 15 mm length Nd:YAG rods. 0.76° tracking error width at 10% laser power loss, and total multimode laser power variation of 0.05% at ±0.1° solar tracking error and 0.30% at ±0.2° solar tracking error were numerically calculated, being 1.27, 74.80 and 21.63 times, respectively, more than the experimental record in solar tracking error compensation capacity attained with a dual-rod side-pumping horizontal prototype pumped by the same heliostat-parabolic system. Additionally, the end-side-pumping configuration of the four-rod solar laser-enabled 43.7 W total multimode solar laser power, leading to 24.7 W/m2 collection efficiency and 2.6% solar-to-laser power conversion efficiency, being 1.75 and 1.44 times, respectively, more than that experimentally obtained from the dual-rod side-pumping prototype. The significant improvement in solar tracking error compensation capacity with a highly efficient end-side-pumping configuration is meaningful because it reduces the cost of high-precision trackers for solar laser applications.
Knowledge-Based Design Algorithm for Support Reduction in Material Extrusion Additive Manufacturing
Authors: Ahn Jaeseung , Doh Jaehyeok , Kim Samyeon , Park Sang-in
Published: October 2022

Although additive manufacturing (AM) enables designers to develop products with a high degree of design freedom, the manufacturing constraints of AM restrict design freedom. One of the key manufacturing constraints is the use of support structures for overhang features, which are indispensable in AM processes, but increase material consumption, manufacturing costs, and build time. Therefore, controlling support structure generation is a significant issue in fabricating functional products directly using AM. The goal of this paper is to propose a knowledge-based design algorithm for reducing support structures whilst considering printability and as-printed quality. The proposed method consists of three steps: (1) AM ontology development, for characterizing a target AM process, (2) Surrogate model construction, for quantifying the impact of the AM parameters on as-printed quality, (3) Design and process modification, for reducing support structures and optimizing the AM parameters. The significance of the proposed method is to not only optimize process parameters, but to also control local geometric features for a better surface roughness and build time reduction. To validate the proposed algorithm, case studies with curve-based (1D), surface-based (2D), and volume (3D) models were carried out to prove the reduction of support generation and build time while maintaining surface quality.
Temperature Sensing Shape Morphing Antenna (ShMoA)
Authors: Zeng Wenxin , Wang Wei , Sonkusale Sameer
Published: October 2022

Devices that can morph their functions on demand provide a rich yet unexplored paradigm for the next generation of electronic devices and sensors. For example, an antenna that can morph its shape can be used to adapt communication to different wireless standards or improve wireless signal reception. We utilize temperature-sensitive shape memory alloys (SMA) to realize a shape morphing antenna (ShMoA). In the designed architecture, multiple conjoined shape memory alloy sections form the antenna. The shape morphing of this antenna is achieved through temperature control. Different temperature threshold levels are used for programming the shape. Besides its conventional use for RF applications, ShMoA can serve as a multi-level temperature sensor, analogous to thermoreceptors in an insect antenna. ShMoA essentially combines the function of temperature sensing, embedded computing for detection of threshold crossings, and radio frequency readout, all in the single construct of a shape-morphing antenna (ShMoA) without the need for any battery or peripheral electronics. The ShMoA can be employed as bio-inspired wireless temperature sensing antennae on mobile robotic flies, insects, drones and other robots. It can also be deployed as programmable antennas for multi-standard wireless communication.
Simple Preparation of Metal-Impregnated FDM 3D-Printed Structures
Authors: Flores Diana , Noboa Jose , Tarapues Mickaela , Vizuete Karla , Debut Alexis , Bejarano Lorena , Streitwieser Daniela Almeida , Ponce Sebastian
Published: October 2022

Modifying the natural characteristics of PLA 3D-printed models is of interest in various research areas in which 3D-printing is applied. Thus, in this study, we describe the simple impregnation of FDM 3D-printed PLA samples with well-defined silver nanoparticles and an iron metal salt. Quasi-spherical and dodecahedra silver particles were strongly attached at the channels of 3D-printed milli-fluidic reactors to demonstrate their attachment and interaction with the flow, as an example. Furthermore, Fenton-like reactions were successfully developed by an iron catalyst impregnated in 3D-printed stirrer caps to induce the degradation of a dye and showed excellent reproducibility.
Combining Four Gaussian Lasers Using Silicon Nitride MMI Slot Waveguide Structure
Authors: Katash Netanel , Khateeb Salman , Malka Dror
Published: October 2022

Transceivers that function under a high-speed rate (over 200 Gb/s) need to have more optical power ability to overcome the power losses which is a reason for using a larger RF line connected to a Mach–Zehnder modulator for obtaining high data bitrate communication. One option to solve this problem is to use a complex laser with a power of over 100 milliwatts. However, this option can be complicated for a photonic chip circuit due to the high cost and nonlinear effects, which can increase the system noise. Therefore, we propose a better solution to increase the power level using a 4 × 1 power combiner which is based on multimode interference (MMI) using a silicon nitride (Si3N4) slot waveguide structure. The combiner was solved using the full-vectorial beam propagation method (FV-BPM), and the key parameters were analyzed using Matlab script codes. Results show that the combiner can function well over the O-band spectrum with high combiner efficiency of at least 98.2% after a short light coupling propagation of 28.78 μm. This new study shows how it is possible to obtain a transverse electric mode solution for four Gaussian coherent sources using Si3N4 slot waveguide technology. Furthermore, the back reflection (BR) was solved using a finite difference time-domain method, and the result shows a low BR of 40.15 dB. This new technology can be utilized for combining multiple coherent sources that work with a photonic chip at the O-band range.
Novel Spiral Silicon Drift Detector with Equal Cathode Ring Gap and Given Surface Electric Fields
Authors: Sun Jiaxiong , Li Zheng , Li Xiaodan , Li Xinqing , Cai Xinyi , Tan Zewen , Liu Manwen , Wang Hongfei
Published: October 2022

Since the advent of semiconductor detectors, they have been developed for several generations, and their performance has been continuously improved. In this paper, we propose a new silicon drift detector structure that is different from the traditional spiral SDD structure that has a gap between the cathode ring and the width of cathode ring, increasing gradually with the increase of the radius of the cathode ring. Our new structure of spiral SDD structure has equal cathode ring gap and a given surface electric field, which has many advantages compared with the traditional structure. The novel SDD structure controllably reduces the area of silicon oxide between the spiral rings, which in turn reduces the surface leakage current due to the reduction of total oxide charge in the silicon oxide and electronic states on the silicon/silicon oxide interface. Moreover, it has better controllability to adjust this spiral ring cathode gap to achieve better surface electric field distribution, thus realizing the optimal carrier drift electric field and achieving the optimal detector performance. In order to verify this theory, we have modeled this new structure and simulated its electrical properties using the Sentaurus TCAD tool. We have also analyzed and compared different spiral ring cathode gap structures (from 10 µm to 25 µm for the gap). According to the simulation results of potential, electric field, and electron concentration, we have obtained that a spiral ring cathode gap of 10 µm has the best electrical characteristics, more uniform distribution of potential and surface electric field, and a more smooth and straight electron drift channel.
Study on the Wetting Mechanism between Hot-Melt Nano Glass Powder and Different Substrates
Authors: Liu Yifang , Chen Junyu , Zheng Gaofeng
Published: October 2022

The wettability of molten glass powder plays an essential role in the encapsulation of microelectromechanical system (MEMS) devices with glass paste as an intermediate layer. In this study, we first investigated the flow process of nano glass powder melted at a high temperature by simulation in COMSOL. Both the influence of the different viscosity of hot-melt glass on its wettability on SiO2 and the comparison of the wettability of hot-melt glass on Au metal lead and SiO2 were investigated by simulation. Then, in the experiment, the hot-melt glass flew and spread along the length of the Au electrode because of a good wettability, resulting in little coverage of the hot-melt glass on the Au electrode, with a height of only 500 nm. In order to reduce the wettability of the glass paste on the Au electrode, a SiO2 isolation layer was grown on the surface of golden lead by chemical vapor deposition. It successfully reduced the wettability, so the thickness of the hot-melt glass was increased to 1.95 μm. This proved once again that the wettability of hot-melt glass on Au was better.
A Systematic Calibration Modeling Method for Redundant INS with Multi-Sensors Non-Orthogonal Configuration
Authors: Gao Chunfeng , Wei Guo , Wang Lin , Wang Qi , Liao Zhikun
Published: October 2022

Because of the non-orthogonal configuration of multi-sensors, the redundant inertial navigation system (INS) has a more complex error model compared with the traditional orthogonal INS, and the complexity of sensors configuration also increases the difficulty of error separation. Based on sufficient analysis of the error principle of redundant IMUs, a generalized high-accuracy calibration modeling method which is suitable for filtering method systematic calibration is summarized in this paper, and it has been applied to an RIMU prototype consisting of four ring laser gyros (RLGs) and four quartz accelerometers. Through the rotational excitation of the three-axis turntable in the laboratory, the high-precision filtering method systematic calibration of the RIMU is achieved, and static navigation and dynamic vehicle test experiments are also carried out. The experimental results reflect that the positioning accuracy can be obviously improved by using this new systematic calibration error model and the validity of this modeling method is also verified.
An Ultra-Compact MEMS Pirani Sensor for In-Situ Pressure Distribution Monitoring
Authors: Zhang Lan , Lu Jian , Takagi Hideki , Matsumoto Sohei , Higurashi Eiji
Published: October 2022

In this study, we designed a microelectromechanical system (MEMS) Pirani vacuum sensor with a compact size. Specifically, the sensor was successfully fabricated based on the Pirani principle and using a commercial eight-inch MEMS foundry process. The sensor fabrication process was carried out using only four photomasks and the proposed sensor had an ultra-compact fabricated size (<2.2 × 2.2 mm2). A vacuum measurement system was set up to comprehensively evaluate the fabricated sensors. The results demonstrated that the MEMS Pirani vacuum sensor has a high responsivity in the low-pressure domain from 100 Pa. The proposed sensor with a 953.0-Ω heater exhibited an average responsivity of 11.9 mV/Pa in the preferred range of 100 to 7 Pa and 96.0 mV/Pa in the range of 7 to 1 Pa. The sensor may be potentially suitable in many applications, such as vacuum indicators for processing equipment, health monitoring systems for social infrastructure, and medical and health applications.
Force Prediction and Material Removal Mechanism Analysis of Milling SiCp/2009Al
Authors: Wang Rong , Zhao Man , Mao Jian , Liang Steven
Published: October 2022

In recent years, medium- and low-volume fraction silicon carbide particle-reinforced aluminum matrix composites (SiCp/Al) have increasingly become a key material in the aerospace industry. Force prediction and material removal mechanism analysis of milling SiCp/Al are necessary to improve the surface integrity of products. An orthogonal experiment of SiCp/2009Al with a volume fraction of 20% was carried out, and the effect of the milling parameters on milling force was studied with the input parameters of milling speed, feed rate, and milling depth. Thereby, the empirical force model of milling SiCp/2009Al is established by fitting the experiential data based on the multiple linear regression analysis methods. Moreover, the effects of the milling parameters on the force were analyzed. Finally, the material removal mechanism of milling SiCp/Al is analyzed based on dislocation theory. The analyzed results reveal that the removal mechanism of the SiCp/Al composites includes plastic deformation of the aluminum matrix, cutting of particles, fragmentation, and deboning. Based on dislocation theory and maximum undeformed thickness theory, the effect of cutting parameters on the form of material removal was analyzed, which serves as a guide for selecting appropriate machining parameters to obtain improved machining quality of SiCp/Al composites.
Progress in the Preparation and Characterization of Convex Blazed Gratings for Hyper-Spectral Imaging Spectrometer: A Review
Authors: Li Huang , Peng Xiaoqiang , Guan Chaoliang , Hu Hao
Published: October 2022

Convex blazed gratings, which can effectively broaden the spectral range and improve spectral resolution, have gradually evolved into a crucial optical component for lightweight and compact imaging spectroscopy instruments. Their design, processing, and testing involve multidisciplinary interdisciplinary scientific issues, and they continue to be a major area of research in imaging optics applications. This paper summarizes the effects of various grating groove shapes and structural parameters on the spectral range and diffraction efficiency of convex blazed gratings, after providing a brief introduction to the typical functions and applications of convex blazed gratings. Firstly, the latest progress in typical processing methods for convex blazed gratings is reviewed. It focuses on the current fabrication processes and reviews their capabilities in creating convex blazed gratings from three main types of technologies, namely ultra-precision machining, high-energy density beam processing, and chemically assisted fabrication processes. Secondly, the adaptability of the manufacturing process for convex blazed gratings on different scales is summarized, analyzing the adaptation of current procedures to various grating fabrication scales and their bottlenecks. Finally, the characterization methods and future feasible characterization methods for convex blazed gratings are reviewed. The development trend of efficient and precise preparation of convex blazed gratings is pointed out.
Theoretical Modeling Method for Material Removal Characteristics of Abrasive Water Jet Polishing under Rotating Oblique Incidence
Authors: Zhang Zhiqiang , Song Ci , Shi Feng , Tie Guipeng , Zhang Wanli , Wang Bo , Tian Ye , Hou Zhanqiang
Published: October 2022

Abrasive water jet polishing (AWJP), as an ultra-precision machining technology, has unique machining advantages. However, the machining application of nozzles in vertical and inclined states is greatly limited because rotational symmetric material removal characteristics and the largest amount of central material removal cannot be obtained. At the same time, considering the many controllable and uncontrollable factors in AWJP, it is difficult to accurately model the removal characteristics obtained by machining. Based on the idea of the Preston equation and the calculation of fluid dynamics, this study first analyzed the material removal characteristics of a single abrasive particle and used FLUENT fluid simulation software to obtain the pressure and velocity distributions at different positions in the processes of nozzle rotation and tilt polishing. By analyzing the influence of the pressure and velocity distributions on material removal and the surface shear stress of the workpiece, a theoretical model of the material removal characteristics of abrasive water jet polishing under rotating oblique incidence was established. Finally, the effectiveness of the theoretical removal model was verified by comparing and analyzing experimental and theoretical results.