- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Longtime stability of silver-based SERS substrate in the environment and (bio)environment with variable temperature and humidity
摘要： The increased involving of Surface Enhanced Raman Spectroscopy (SERS) in the analytical and bioanalytical field makes this technique commercially available. However, the growing range of available SERS substrates opens the question regarding the stability of SERS substrates during their storage, transportation, and utilization. In this paper, we present systematical study of the stability of SERS enhanced response of SERS-active silver grating under various physical and chemical loads. The silver coated periodical gratings provide excellent enhancement and reproducibility of SERS signal, achieved at the macroscale. The substrate load procedures include the temperature, humidity tests, and their combination. Since the utilization of SERS substrates often involves their interaction with various (bio)environments, the effects of physiological media were studied too. In all cases, the effects of the loads were determined from the changes of SERS effectivity and reproducibility.
关键词： SERS,Substrate,Temperature,(Bio)environment,Stability,Humidity
更新于2025-09-23 15:23:52
-
Microstructure and tribological properties of laser cladded self-lubricating nickel-base composite coatings containing nano-Cu and h-BN solid lubricants
摘要： In the present work, nickel-base composite powder (Ni60), nickel-base composite powder with the addition of h-BN solid lubricants (h-BN/Ni60) and nickel-base composite powder with the addition of nano-Cu encapsulated h-BN solid lubricants (nano-Cu/h-BN/Ni60) were used as raw materials to synthesize three different coatings on Q235 steels by laser cladding. Microstructures of these coatings were analyzed by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and Raman spectroscopy. Tribological properties of these coatings were investigated at the temperatures from 25 °C to 600 °C. High temperature micro-hardness measurement was performed by Vickers micro-hardness tester. The results showed that the h-BN particles survived after laser cladding and displayed a homogeneous distribution in the nickel-base composite matrix. The encapsulation of h-BN by nano-Cu resulted in an increase of h-BN content in the coating. Although the addition of nano-Cu and h-BN led to a decrease on hardness, the nano-Cu/h-BN/Ni60 coating had the lowest friction coefficient and wear rate among the three coatings in a wide range of temperature from 25 °C to 500 °C. The mechanism of wear reduction by addition of nano-Cu encapsulated h-BN solid-lubricants was also discussed in this research.
关键词： Laser cladding,Self-lubricant coating,Steel substrate,Wear,Wide temperature range,Nickel-base composite
更新于2025-09-23 15:23:52
-
Effect of post-annealing on microstructure and piezoelectric properties of ZnO thin film for triangular shaped vibration energy harvester
摘要： In this paper, a triangular shaped piezoelectric vibration energy harvester (TS-PVEH) with zinc oxide (ZnO) thin films as the piezoelectric layer is reported. The effect of post-annealing temperature on the microstructure and piezoelectric performance of ZnO thin film deposited by magnetron sputtering method is investigated firstly. The results show that the optimum post-annealing temperature of 150 °C was the most beneficial to improve the piezoelectric properties of ZnO thin films. Four prototypes of TS-PVEH with different structure parameters are fabricated and optimized. The simulation and experiment results indicate that the height and width of the triangular structure have a significant influence on the vibration mode and the output performance of TS-PVEHs. The optimization results indicate that the third prototype has the best output performance. Its open-circuit voltage and short-circuit current are 290mV and 1.25 μA, respectively, when the vibration acceleration is 5m/s2 and the frequency is 56Hz. Moreover, it has the highest load power density of 0.035μW/cm2 when the load is 0.1MΩ.
关键词： Triangular substrate,ZnO thin film,Structure optimization,Post-annealing temperature,Vibration energy harvester
更新于2025-09-23 15:23:52
-
Piezoelectric and ferroelectric characteristics of P(VDF-TrFE) thin films on Pt and ITO substrates
摘要： Organic P(VDF-TrFE) 70/30 copolymer thin films were fabricated on Pt/Ti/SiO2/Si(1 1 1) and ITO/glass substrates at 140 °C using a spin coater. Both P(VDF-TrFE) thin films exhibited ferroelectric β-phase crystallinity, as confirmed by X-ray diffraction analysis. The polarization–electric hysteresis loops of the P(VDF-TrFE) thin films on the Pt and indium-tin-oxide substrates showed high remnant polarizations of 15.5 and 11.8 μC/cm2, respectively. Atomic force microscopy characterization showed rod-like features of the P(VDF-TrFE) thin films on both substrates, where larger rod diameters were observed on the Pt substrate compared to those fabricated on the ITO substrate. Piezoelectric force microscopy measurements further confirmed the superior piezoelectric and ferroelectric properties of the P(VDF-TrFE) thin films on the Pt substrate compared to those on the ITO substrate, which arose from the increased diameter of the rod-like features.
关键词： Piezoelectricity,Ferroelectricity,P(VDF-TrFE) thin film,ITO substrate,Pt substrate
更新于2025-09-23 15:22:29
-
[IEEE 2018 IEEE 13th Annual International Conference on Nano/Micro Engineered and Molecular Systems (NEMS) - Singapore, Singapore (2018.4.22-2018.4.26)] 2018 IEEE 13th Annual International Conference on Nano/Micro Engineered and Molecular Systems (NEMS) - Self-Powered, High-Sensitive Human Cutaneous Activities Sensor
摘要： A self-powered piezoelectric sensor based on lead-free (K,Na)NbO3 (KNN) thin film for human health monitoring is presented. The sensor is fabricated on a flexible substrate and exhibits high sensitivity and stability. It can detect various physiological signals such as pulse, respiration, and body movement. The results demonstrate its potential for wearable health monitoring applications.
关键词： piezoelectric sensor,KNN thin film,health monitoring,lead-free,flexible substrate,wearable
更新于2025-09-23 15:22:29
-
Design of a Circularly Polarized Dielectric Resonator Antenna with Wide Bandwidth and Low Axial Ratio Values
摘要： A circularly polarized (CP) dielectric resonator antenna (DRA) with wide bandwidth and low axial ratio (AR) values is presented in this communication. The antenna consists of a stacked DRA, and it is fed by a substrate integrated waveguide (SIW) coupling slot from the bottom. The stacked DRA structure, with high permittivity dielectric strips layered on low permittivity substrate, is adopted for bandwidth and gain benefits. Here, a pair of dielectric strips rather than a single one is placed above the coupling slot with 45° inclination for generating good CP radiation, and it is elaborately designed to provide three closely coupled CP modes, constituting a wide operating bandwidth. To facilitate the application in antenna array, a cavity-backed antenna design along with a 2×2 sub-array are further presented. To verify the design, a sub-array prototype is developed and tested at Ku-band for satellite applications, showing an impedance bandwidth of 25.1%, a wide 1-dB AR bandwidth of 15.6%, and a peak gain of 15.1dBi.
关键词： substrate integrated waveguide,low axial ratio values,wide bandwidth,Dielectric resonator antenna
更新于2025-09-23 15:22:29
-
[IEEE 2018 IEEE International Workshop on Electromagnetics: Applications and Student Innovation Competition (iWEM) - Nagoya (2018.8.29-2018.8.31)] 2018 IEEE International Workshop on Electromagnetics:Applications and Student Innovation Competition (iWEM) - E-Plane Beam-Forming Performance of Rotman-Lens in Multi-Layer Substrate
摘要： A two-dimensional Rotman-lens feeding circuit was proposed for planar two-dimensional multi-beam antenna using multi-layer substrate integrated waveguide in the millimeter-wave band. In this work, an E-plane Rotman-lens for two-dimensional Rotman-lens was designed and the E-plane beam-forming performance was evaluated by array factors from the simulated S-parameters.
关键词： multi-beam antenna,feeding circuit,multi-layer substrate,millimeter-wave,Rotman-lens
更新于2025-09-23 15:22:29
-
Monolithic integration of E/D-mode GaN MIS-HEMTs on ultrathin-barrier AlGaN/GaN heterostructure on Si substrates
摘要： Monolithically integrated enhancement/depletion-mode (E/D-mode) GaN-based metal–insulator–semiconductor high-electron-mobility transistors (MIS-HEMTs) and inverters, were fabricated on an ultrathin-barrier (UTB) AlGaN/GaN heterostructure grown on Si substrates. By employing a graded AlGaN back barrier in the UTB-AlGaN/GaN heterostructure, a high threshold voltage (VTH) of +3.3 V is achieved in the E-mode MIS-HEMTs. The fabricated MIS-HEMT inverter features a high logic swing voltage of 7.76 V at a supply voltage of 8 V, a small VTH hysteresis as well as deviation less than 0.2 V. The UTB AlGaN/GaN-on-Si technology provides a good platform for integration of MIS-gate-based drivers and power transistors.
关键词： monolithic integration,ultrathin-barrier,GaN,E/D-mode,MIS-HEMT,inverter,AlGaN/GaN heterostructure,Si substrate
更新于2025-09-23 15:22:29
-
Effects of substrate temperature and precursor amount on optical properties and microstructure of CVD deposited amorphous TiO2 thin films
摘要： In this research, TiO2 thin films were deposited on glass substrate by chemical vapor deposition using tetra isopropylorthotitanate as a precursor at low temperature. The TiO2 thin films were formed without using an oxygen source or annealing. Effects of substrate temperature and amount of the precursor on surface microstructure and optical properties of deposited TiO2 thin films were investigated. X-ray diffraction (XRD), UV-visible spectrophotometry and atomic force microscopy (AFM) were used to analyze the fabricated layers. The XRD analysis revealed that structure of all prepared layers was in amorphous phase. Analysis of AFM images showed that by increasing substrate temperature, the layer surfaces became rougher and simultaneously nanoparticle size was more uniform. Texture analysis revealed that increasing substrate temperature and decreasing precursor amount both increased surface isotropy. Thickness of layers was calculated by applying the Swanepoel method to the transmittance spectra. Variations in optical parameters were studied, including of optical band gap, refractive index, extinction coefficient, complex dielectric function, Urbach energy, single oscillator energy and dispersion energy. The results indicated that optical properties were functions of substrate temperature and precursor amount.
关键词： CVD,TiO2 thin film,Substrate temperature,Optical properties,Amorphous structure
更新于2025-09-23 15:22:29
-
Effect of temperature and bias voltage on electrical and electrochemical properties of diamond-like carbon films deposited with HiPIMS
摘要： The relatively high electrical resistivity of diamond-like carbon (DLC) film is one of the main drawbacks when applied in electronic device. In this study, DLC films were synthesized on 304 stainless steels by high power impulse magnetron sputtering (HiPIMS) process and the effect of deposition temperature and bias voltage on the microstructure, electrical and electrochemical properties, hardness and adhesion strength of the DLC films were investigated. The sp2/sp3 ratio of DLC films first decreased then increased and the surface became denser as bias voltage increasing from 0 to -400 V. While the film turned into graphite-like structure and became incompact when deposition temperature rose from 100 °C to 300 °C. The interfacial contact resistance (ICR) got reduced by increasing bias voltage and deposition temperature. However, as the deposition temperature increased to 300 °C the anticorrosion ability and hardness of DLC films deteriorated. The DLC films deposited at 300 °C presented soft and had better adhesion strength than hard DLC films deposited at 100 °C. DLC films deposited at -400 V bias and 300 °C had the lowest ICR while DLC films deposited at -400 V bias and 100 °C had the best performance when ICR, corrosion resistance and hardness were all taken into consideration.
关键词： Electrochemical corrosion,Substrate temperature,High power impulse magnetron sputtering,Interfacial conductivity,Diamond-like carbon,Bias voltages
更新于2025-09-23 15:22:29