The Optical and Electrical Performance of CuO Synthesized by Anodic Oxidation Based on Copper Foam

Metal oxide semiconductor materials have a wide range of applications in the field of solar energy conversion. In this paper, CuO was prepared directly on copper foam substrate by anodic oxidation. The effects of current density and anodizing temperature on sample preparation and performance were studied. Field emission scanning electron microscopy (FESEM) and X-ray diffractometer (XRD) had been used to determine the morphology and phase structure of the sample, and its optical and electrical properties were discussed through UV-vis spectrophotometer and electrochemical tests. In addition, the influences of experimental conditions such as current density and reaction temperature on the morphology and properties of CuO were systematically discussed. The FESEM images showed that as the anodic oxidation temperature increase, the morphology of the prepared sample changed from nanowires to leaf-like CuO nanosheets. According to the results of XRD, the structure of prepared CuO was monoclinic, and the intensity of diffraction peaks gradually increased as anodizing temperature increased. We found that the optimum current density and anodizing temperature were 20 mA cm−2 and 60 °C, respectively. The results of electrochemical indicated that the CuO electrode based on copper foam (CuO/Cu foam) prepared at the optimum exhibited the highest specific capacitance (0.1039 F cm−2) when the scan rate was 2 mV s−1.

Download Full-text

Laser-Induced Plasma Micromachining Process: Principles and Performance

Journal of Micro and Nano-Manufacturing ◽

10.1115/1.4030706 ◽

2015 ◽

Vol 3 (3) ◽

Cited By ~ 6

Author(s):

Kumar Pallav ◽

Ishan Saxena ◽

K. F. Ehmann

Keyword(s):

Material Removal ◽

Dielectric Breakdown ◽

Dielectric Material ◽

Experimental Conditions ◽

Plasma Generation ◽

Laser Induced Plasma ◽

Wide Range ◽

Matter Interaction ◽

And Performance ◽

Ultrashort Laser

Laser-induced plasma micromachining (LIP-MM) is a novel multimaterial and tool-less micromachining process. It utilizes tightly focused ultrashort laser irradiation to generate plasma through laser-induced dielectric breakdown in a dielectric material. The plasma facilitates material removal through plasma–matter interaction spot through vaporization and ablation. The paper introduces the LIP-MM process, discusses the underlying principles behind plasma generation and machining, and proves its feasibility by describing the experimental conditions under which plasma generation and machining occur. Upon successful commercial realization of this novel process, the key benefits envisaged are micromachining with better accuracy and better surface integrity, minimal subsurface damage, relatively smaller heat-affected zone (HAZ) and low roughness in a wide range of materials including those that are difficult to machine by some of the most successful micromachining processes such as micro-electrodischarge machining (EDM) and laser ablation.

Download Full-text

Strongly Coupled Redox-Linked Conformational Switching at the Active Site of the Non-Heme Iron-Dependent Dioxygenase, TauD

10.26434/chemrxiv.9461462 ◽

2019 ◽

Author(s):

Christopher John ◽

Greg M. Swain ◽

Robert P. Hausinger ◽

Denis A. Proshlyakov

Keyword(s):

Active Site ◽

Structural Model ◽

Heme Iron ◽

Chemical Transformations ◽

Experimental Conditions ◽

Strongly Coupled ◽

Non Heme Iron ◽

Reversible Redox ◽

Wide Range ◽

Complex Structural

2-Oxoglutarate (2OG)-dependent dioxygenases catalyze C-H activation while performing a wide range of chemical transformations. In contrast to their heme analogues, non-heme iron centers afford greater structural flexibility with important implications for their diverse catalytic mechanisms. We characterize an <i>in situ</i> structural model of the putative transient ferric intermediate of 2OG:taurine dioxygenase (TauD) by using a combination of spectroelectrochemical and semi-empirical computational methods, demonstrating that the Fe (III/II) transition involves a substantial, fully reversible, redox-linked conformational change at the active site. This rearrangement alters the apparent redox potential of the active site between -127 mV for reduction of the ferric state and 171 mV for oxidation of the ferrous state of the 2OG-Fe-TauD complex. Structural perturbations exhibit limited sensitivity to mediator concentrations and potential pulse duration. Similar changes were observed in the Fe-TauD and taurine-2OG-Fe-TauD complexes, thus attributing the reorganization to the protein moiety rather than the cosubstrates. Redox difference infrared spectra indicate a reorganization of the protein backbone in addition to the involvement of carboxylate and histidine ligands. Quantitative modeling of the transient redox response using two alternative reaction schemes across a variety of experimental conditions strongly supports the proposal for intrinsic protein reorganization as the origin of the experimental observations.

Download Full-text

STEREOTYPE THREAT AND STEREOTYPE LIFT: THE CASE OF 10 YEAR OLD GIRLS AND BOYS

Civitas et Lex ◽

10.31648/cetl.2339 ◽

2016 ◽

Vol 12 (4) ◽

pp. 21-32

Author(s):

Anna Kwiatkowska ◽

Małgorzata Mróz

Keyword(s):

Stereotype Threat ◽

Cognitive Performance ◽

Significant Interaction ◽

Self Esteem ◽

The Self ◽

Experimental Conditions ◽

Significant Interaction Effect ◽

Significant Drop ◽

Stereotype Lift ◽

And Performance

The aim of this study was to examine the effects of stereotypical and counter-stereotypicalinformation on the self-esteem and cognitive performance of 10-year-old children. Our sampleconsisted of 37 girls and 37 boys. Children were presented with 10 “mathematical” puzzles in threeexperimental conditions: stereotypical (boys are better), counter-stereotypical (girls are better), andthe control condition (no particular information). Self-esteem was measured using a non-verbaltask. The results showed a significant interaction effect of “condition x sex” on self-esteem andperformance. Girls revealed no significant differences between control and experimental conditions,while boys showed a significant drop in self-esteem and performance in the counter-stereotypicalcondition as compared to the control condition and a significant lift in self-esteem and performancein the stereotypical condition as compared to the control condition.

Download Full-text

Analysis of organic removal rates in the aerated submerged fixed film process

Water Science & Technology ◽

10.2166/wst.1998.0809 ◽

1998 ◽

Vol 38 (8-9) ◽

pp. 213-221 ◽

Cited By ~ 3

Author(s):

Mohamed F. Hamoda ◽

Ibrahim A. Al-Ghusain

Keyword(s):

Pilot Plant ◽

Removal Rate ◽

Domestic Wastewater ◽

Removal Rates ◽

Hydraulic Loading ◽

Organic Removal ◽

Wide Range ◽

Fixed Film ◽

Cod Removal Rate ◽

And Performance

Performance data from a pilot-plant employing the four-stage aerated submerged fixed film (ASFF) process treating domestic wastewater were analyzed to examine the organic removal rates. The process has shown high BOD removal efficiencies (> 90%) over a wide range of hydraulic loading rates (0.04 to 0.68 m3/m2·d). It could also cope with high hydraulic and organic loadings with minimal loss in efficiency due to the large amount of immobilized biomass attained. The organic (BOD and COD) removal rate was influenced by the hydraulic loadings applied, but organic removal rates of up to 104 kg BOD/ m2·d were obtained at a hydraulic loading rate of 0.68 m3/m2·d. A Semi-empirical model for the bio-oxidation of organics in the ASFF process has been formulated and rate constants were calculated based on statistical analysis of pilot-plant data. The relationships obtained are very useful for analyzing the design and performance of the ASFF process and a variety of attached growth processes.

Download Full-text

Low-Energy Electron Damage to Condensed-Phase DNA and Its Constituents

International Journal of Molecular Sciences ◽

10.3390/ijms22157879 ◽

2021 ◽

Vol 22 (15) ◽

pp. 7879

Author(s):

Yingxia Gao ◽

Yi Zheng ◽

Léon Sanche

Keyword(s):

Condensed Phase ◽

Genetic Material ◽

High Energy ◽

Dna Lesions ◽

Low Energy ◽

Experimental Investigations ◽

Experimental Conditions ◽

Strand Breaks ◽

Sequence Of Events ◽

Wide Range

The complex physical and chemical reactions between the large number of low-energy (0–30 eV) electrons (LEEs) released by high energy radiation interacting with genetic material can lead to the formation of various DNA lesions such as crosslinks, single strand breaks, base modifications, and cleavage, as well as double strand breaks and other cluster damages. When crosslinks and cluster damages cannot be repaired by the cell, they can cause genetic loss of information, mutations, apoptosis, and promote genomic instability. Through the efforts of many research groups in the past two decades, the study of the interaction between LEEs and DNA under different experimental conditions has unveiled some of the main mechanisms responsible for these damages. In the present review, we focus on experimental investigations in the condensed phase that range from fundamental DNA constituents to oligonucleotides, synthetic duplex DNA, and bacterial (i.e., plasmid) DNA. These targets were irradiated either with LEEs from a monoenergetic-electron or photoelectron source, as sub-monolayer, monolayer, or multilayer films and within clusters or water solutions. Each type of experiment is briefly described, and the observed DNA damages are reported, along with the proposed mechanisms. Defining the role of LEEs within the sequence of events leading to radiobiological lesions contributes to our understanding of the action of radiation on living organisms, over a wide range of initial radiation energies. Applications of the interaction of LEEs with DNA to radiotherapy are briefly summarized.

Download Full-text

Review of the Upright Balance Assessment Based on the Force Plate

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph18052696 ◽

2021 ◽

Vol 18 (5) ◽

pp. 2696

Author(s):

Baoliang Chen ◽

Peng Liu ◽

Feiyun Xiao ◽

Zhengshi Liu ◽

Yong Wang

Keyword(s):

Postural Balance ◽

Force Plate ◽

Assessment Method ◽

Balance Assessment ◽

Experimental Conditions ◽

Methodological Research ◽

Assessment Tests ◽

Wide Range ◽

Foot Posture ◽

Plate System

Quantitative assessment is crucial for the evaluation of human postural balance. The force plate system is the key quantitative balance assessment method. The purpose of this study is to review the important concepts in balance assessment and analyze the experimental conditions, parameter variables, and application scope based on force plate technology. As there is a wide range of balance assessment tests and a variety of commercial force plate systems to choose from, there is room for further improvement of the test details and evaluation variables of the balance assessment. The recommendations presented in this article are the foundation and key part of the postural balance assessment; these recommendations focus on the type of force plate, the subject’s foot posture, and the choice of assessment variables, which further enriches the content of posturography. In order to promote a more reasonable balance assessment method based on force plates, further methodological research and a stronger consensus are still needed.

Download Full-text

An Investigation of the Physical and Electrical Properties of Knitted Electrodes When Subjected to Multi-Axial Compression and Abrasion

Proceedings ◽

10.3390/proceedings2021068002 ◽

2021 ◽

Vol 68 (1) ◽

pp. 2

Author(s):

Arash M. Shahidi ◽

Theodore Hughes-Riley ◽

Carlos Oliveira ◽

Tilak Dias

Keyword(s):

Heart Rate ◽

Electrical Properties ◽

Applied Load ◽

Pressure Sensors ◽

Electrical Performance ◽

Electronic Textiles ◽

Heart Rate Monitors ◽

Mechanical Loads ◽

And Performance ◽

Over Time

Knitted electrodes are a key component to many electronic textiles including sensing devices, such as pressure sensors and heart rate monitors; therefore, it is essential to assess the electrical performance of these knitted electrodes under different mechanical loads to understand their performance during use. The electrical properties of the electrodes could change while deforming, due to an applied load, which could occur in the uniaxial direction (while stretched) or multiaxial direction (while compressed). The properties and performance of the electrodes could also change over time when rubbed against another surface due to the frictional force and generated heat. This work investigates the behavior of a knitted electrode under different loading conditions and after multiple abrasion cycles.

Download Full-text

Study and Assessment of Defect and Trap Effects on the Current Capabilities of a 4H-SiC-Based Power MOSFET

Electronics ◽

10.3390/electronics10060735 ◽

2021 ◽

Vol 10 (6) ◽

pp. 735

Author(s):

Fortunato Pezzimenti ◽

Hichem Bencherif ◽

Giuseppe De Martino ◽

Lakhdar Dehimi ◽

Riccardo Carotenuto ◽

...

Keyword(s):

Drain Current ◽

Oxide Semiconductor ◽

Temperature Dependent ◽

Channel Mobility ◽

Blocking Voltage ◽

Current Voltage ◽

Wide Range ◽

Temperature Ranges ◽

Joint Contribution ◽

State Resistance

A numerical simulation study accounting for trap and defect effects on the current-voltage characteristics of a 4H-SiC-based power metal-oxide-semiconductor field effect transistor (MOSFET) is performed in a wide range of temperatures and bias conditions. In particular, the most penalizing native defects in the starting substrate (i.e., EH6/7 and Z1/2) as well as the fixed oxide trap concentration and the density of states (DoS) at the 4H-SiC/SiO2 interface are carefully taken into account. The temperature-dependent physics of the interface traps are considered in detail. Scattering phenomena related to the joint contribution of defects and traps shift the MOSFET threshold voltage, reduce the channel mobility, and penalize the device current capabilities. However, while the MOSFET on-state resistance (RON) tends to increase with scattering centers, the sensitivity of the drain current to the temperature decreases especially when the device is operating at a high gate voltage (VGS). Assuming the temperature ranges from 300 K to 573 K, RON is about 2.5 MΩ·µm2 for VGS > 16 V with a percentage variation ΔRON lower than 20%. The device is rated to perform a blocking voltage of 650 V.

Download Full-text

A Novel Ultrasonic TOF Ranging System Using AlN Based PMUTs

Micromachines ◽

10.3390/mi12030284 ◽

2021 ◽

Vol 12 (3) ◽

pp. 284

Author(s):

Yihsiang Chiu ◽

Chen Wang ◽

Dan Gong ◽

Nan Li ◽

Shenglin Ma ◽

...

Keyword(s):

Clock Cycle ◽

High Accuracy ◽

Ultrasonic Waves ◽

Oxide Semiconductor ◽

Average Error ◽

Cmos Process ◽

Clock Frequency ◽

Time Frequency ◽

Range Finding ◽

Wide Range

This paper presents a high-accuracy complementary metal oxide semiconductor (CMOS) driven ultrasonic ranging system based on air coupled aluminum nitride (AlN) based piezoelectric micromachined ultrasonic transducers (PMUTs) using time of flight (TOF). The mode shape and the time-frequency characteristics of PMUTs are simulated and analyzed. Two pieces of PMUTs with a frequency of 97 kHz and 96 kHz are applied. One is used to transmit and the other is used to receive ultrasonic waves. The Time to Digital Converter circuit (TDC), correlating the clock frequency with sound velocity, is utilized for range finding via TOF calculated from the system clock cycle. An application specific integrated circuit (ASIC) chip is designed and fabricated on a 0.18 μm CMOS process to acquire data from the PMUT. Compared to state of the art, the developed ranging system features a wide range and high accuracy, which allows to measure the range of 50 cm with an average error of 0.63 mm. AlN based PMUT is a promising candidate for an integrated portable ranging system.

Download Full-text

Fabrication and Compressive Behavior of a Micro-Lattice Composite by High Resolution DLP Stereolithography

Polymers ◽

10.3390/polym13050785 ◽

2021 ◽

Vol 13 (5) ◽

pp. 785

Author(s):

Chow Shing Shin ◽

Yu Chia Chang

Keyword(s):

High Resolution ◽

Lattice Structure ◽

Low Cost ◽

Hierarchical Structures ◽

Dip Coating ◽

Unit Cell ◽

Digital Light Processing ◽

Unit Cell Size ◽

Wide Range ◽

And Performance

Lattice structures are superior to stochastic foams in mechanical properties and are finding increasing applications. Their properties can be tailored in a wide range through adjusting the design and dimensions of the unit cell, changing the constituent materials as well as forming into hierarchical structures. In order to achieve more levels of hierarchy, the dimensions of the fundamental lattice have to be small enough. Although lattice size of several microns can be fabricated using the two-photon polymerization technique, sophisticated and costly equipment is required. To balance cost and performance, a low-cost high resolution micro-stereolithographic system has been developed in this work based on a commercial digital light processing (DLP) projector. Unit cell lengths as small as 100 μm have been successfully fabricated. Decreasing the unit cell size from 150 to 100 μm increased the compressive stiffness by 26%. Different pretreatments to facilitate the electroless plating of nickel on the lattice structure have been attempted. A pretreatment of dip coating in a graphene suspension is the most successful and increased the strength and stiffness by 5.3 and 3.6 times, respectively. Even a very light and incomplete nickel plating in the interior has increase the structural stiffness and strength by more than twofold.

Download Full-text