- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Investigation of hole quality in drilled Ti/CFRP/Ti laminates using CO2 laser
摘要： The machinability of titanium (Ti) and carbon fiber reinforced plastic (CFRP) (Ti/CFRP/Ti) laminates using CO2 laser is presented in this work. The effect of line energy and laser frequency on output responses such as heat affected zone (HAZ), taper angle (TA), metal composite interface (MCI) damage, surface roughness, dross height, and circularity were investigated. Line energy - the most influential parameter - demonstrated a threshold behavior; no drilling was observed below a certain line energy. Scanning acoustic microscopy (SAM), scanning electron microscopy (SEM), micro-computed tomography (μ-CT), and other imaging techniques were used to establish a correlation between laser parameters and CO2 laser machined damage in Ti/CFRP/Ti laminates. The results show that using a higher frequency and lower line energy can significantly improve the hole quality. However, dross free holes with minimum taper can be obtained using higher line energy.
关键词： Surface roughness,Circularity,Micro-hardness,CO2 laser,Dross height,HAZ,Drilling,Ti/CFRP/Ti,MCI damage factor,TA
更新于2025-09-23 15:19:57
-
Serum VEGF and Ang-2 Levels in Infants Before and After Laser Treatment for Retinopathy of Prematurity
摘要： Objectives: To investigate VEGF and Ang-2 level changes in the systemic circulation after laser photocoagulation in premature infants with ROP. Methods: Eleven infants (4 girls and 7 boys) had serum levels determined for VEGF and Ang-2, collected 1 day prior to and 7 days after ROP laser therapy. Serum levels of VEGF and Ang-2 were quantified by enzyme-linked immunosorbent assay (ELISA). Results: Serum VEGF levels were significantly lower at 7 days after laser therapy compared to that at 1 day prior to laser therapy (p ? 0.045). Serum Ang-2 levels increased significantly at 7 days after laser therapy compared with that at 1 day prior to laser therapy (p ? 0.046). Conclusions: Serum VEGF levels in patients with ROP were suppressed and Ang-2 levels elevated significantly after laser therapy. The results suggest that changes in VEGF and Ang-2 serum levels may reflect regression and treatment of ROP.
关键词： angiopoietin 2,premature infants,serum levels,Retinopathy of prematurity,vascular endothelial growth factor
更新于2025-09-23 15:19:57
-
[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Systematic Design of Photonic Crystal Cavities with Ultra-Low Modal Volume Considering Different Fabrication Resolutions
摘要： Sparsity of the ratings available in the recommender system database makes the task of rating prediction a highly underdetermined problem. This poses a limit on the accuracy and the quality of prediction. In this paper, we utilize secondary information pertaining to user’s demography and item categories to enhance prediction accuracy. Within the matrix factorization framework, we introduce additional supervised label consistency terms that match the user and item factor matrices to the available secondary information (metadata). Matrix factorization model—conventionally employed in collaborative ?ltering techniques—yields dense user and dense item factor matrices—the assumption is that users have an af?nity toward all latent factors and items possess all latent factors. Our formulation, based on a recent work, aims to recover a dense user and a sparse item factor matrix—this is a more reasonable model. Human beings show a natural interest toward all the factors, but every item cannot possess all the factors; this leads to a sparse item factor matrix. A natural outcome of our proposal is a solution to the pure cold start problem. We utilize the label consistency map generated from the proposed model to make reasonable recommendations for new users and new items which have not (been) rated yet. We demonstrate the performance of our model for a movie recommendation system. We also design an ef?cient algorithm for our formulation.
关键词： cold start,blind compressive sensing,matrix factorization,latent factor model,Auxiliary information
更新于2025-09-23 15:19:57
-
[IEEE 2019 IEEE 26th International Symposium on the Physical and Failure Analysis of Integrated Circuits (IPFA) - Hangzhou, China (2019.7.2-2019.7.5)] 2019 IEEE 26th International Symposium on Physical and Failure Analysis of Integrated Circuits (IPFA) - Application of Laser Deprocessing Technique in Physical Failure Analysis on Memory Bit-counting
摘要： This paper introduces a digitally controlled single-phase rectifier with power factor correction (PFC) based on a modified three-level boost converter topology. In comparison with the conventional boost-based systems, the new PFC rectifier has about three times smaller inductor and significantly lower switching losses. The improvements are achieved by replacing the output capacitor of the boost converter with a nonsymmetric active capacitive divider, with a 3:1 division ratio, and by utilizing the downstream converter stage for the capacitive divider’s center-tap voltage regulation. The nonsymmetric voltage divider and applied switching sequence effectively provide four-level converter behavior using the same number of components as three-level converters. As a result, a 66% reduction of the inductor compared to the conventional boost-based PFC and a 33% compared to the standard three-level solutions operating at the same effective switching frequencies are also achieved. Experimental results obtained with a 400 W, 200 kHz, universal input voltage (85 Vrms –265 Vrms ) PFC prototype demonstrate three times smaller inductor current ripple than that of the conventional boost converter allowing for the same inductor reduction. Efficiency improvements of up to a 6% are also demonstrated.
关键词： boost converter,power factor correction (PFC),multilevel converters,AC-DC converters
更新于2025-09-23 15:19:57
-
Efficient NDT small molecule solar cell with high fill factor by pendant group engineering
摘要： Three naphthodithiophene (NDT)-based small molecules, bearing hexyl- (NDT-Hex), null (NDT) and fluorene (NDT-F) substituents at the β-position of the thiophene vertically conjugated to the NDT core, were designed and synthesized. The photovoltaic effect of engineered NDT molecules was investigated with detailed characterization on optical absorption, electronic energy levels, blend morphology, carrier mobility and photovoltaic performance conducted. It shows that the hexyl-substitution enhances the morphological tunability for NDT molecules, which contributes to achieve promising power conversion efficiency (PCE) with high fill factor (FF). The optimized solar cells based on NDT-Hex:PC71BM blends obtains a PCE of 6.7% with an FF of 0.717 and it reaches 8.6% with an FF of 0.638 if a non-fullerene molecular acceptor, NBDTP-Fout, was adopted to blend with NDT-Hex. Both FF are among the top ones of respective kind of solar cells based on NDT small molecule. The work demonstrates a feasible morphology-tuning method toward efficient organic solar cells with high FF.
关键词： morphology-tuning,naphthodithiophene,small molecule solar cells,high fill factor,pendant group engineering
更新于2025-09-23 15:19:57
-
An improved mathematical model of photovoltaic cells based on datasheet information
摘要： In order to tackle the nonlinear transcendental equation and intractability of traditional photovoltaic (PV) cells model, this paper proposes a two-step modeling method based on datasheet information. Firstly, grounded on the assumption that the open circuit voltage and short circuit current are independent of series resistance Rs and shunt resistance Rsh, the PV cells model is separated as the ideal model part and the resistance network part. Then, according to the data provided by the manufacturer under Standard Test Conditions (STC) and Nominal Operating Cell Temperature (NOCT) conditions, the parameters photocurrent Iph, reverse saturation current Io and ideality factor n are obtained to achieve the purpose of modeling the ideal model part. Meanwhile, the parameters Rs and Rsh are obtained according to the data provided by the manufacturer under STC to achieve the purpose of modeling the resistance network part. Finally, the open circuit voltage and short circuit current of three di?erent material types of PV cells are obtained by the modeling method and compared with the actual experimental data to verify the mentioned assumption. Moreover, the current-voltage characteristic curves of these three PV cells are also obtained and the corresponding errors are analyzed and discussed.
关键词： Five-parameters model,Datasheet information,Current-voltage characteristic curve,Photovoltaic cells,Ideality factor
更新于2025-09-23 15:19:57
-
Performance Analysis of Mixed Carrier-pulse Width Modulation Scheme
摘要： This study deals with the performance analysis of Pulse Width Modulation (PWM) scheme for three phase voltage source inverter though intermingling of multiple carriers. The proposed PWM scheme using two groups of carriers (inverted Sine wave and Triangle wave), each group having carrier and its 90° shifted. The arbitrary selection of these carriers is based on the linear feedback shift registers value (‘0’ or ‘1’). This random carrier selection is serving to improve the spectral quality of the output of the inverter. This improved waveform has been derived from third harmonic injected sine PWM technique. Simulation results confirm the effectiveness of the proposed scheme in providing very less harmonic noises with minimum distortion and satisfactory fundamental component. This study also shows the implementation compatibility of the work with Field Programmable Gate Array environment.
关键词： Harmonic spread factor,voltage source inverter,linear feedback shift register,random pulse width modulation,pseudo random binary sequence
更新于2025-09-23 15:19:57
-
PACAP through EGFR transactivation preserves human corneal endothelial integrity
摘要： The corneal endothelium is composed of a single hexagonal‐shaped cells layer adherent to the Descemet's membrane. The primary function of these cells is maintaining of tissue clarity by regulating its hydration. Trauma, aging or other pathologies cause their loss, counterbalanced by enlargement of survived cells fluid pumping to and from the stroma. unable to guarantee an efficient Regenerative medicine using human corneal endothelial cells (HCECs) isolated from peripheral corneal‐scleral tissue of a donor could be an attractive solution, overcoming transplantation problems. In a previous study, we have demonstrated that HCECs treatment with pituitary adenylate cyclase–activating polypeptide following growth factors deprivation prevents their degeneration. (PACAP) However, the molecular mechanism mediating this effect has not been clarified, yet. Here, we have shown for the first time the expression of PACAP and its receptor (PAC1R) in human corneal endothelium and demonstrated that this peptide, selectively binding to PAC1R, induces epidermal growth factor receptor (EGFR) phosphorylation and the MAPK/ERK1/2 signaling pathway activation. In conclusion, our data have suggested that PACAP could represent an important trophic factor in maintaining human corneal endothelial integrity through EGFR transactivation. Therefore, PACAP, as well as epidermal growth factor and fibroblast growth factor, could co‐operate to guarantee tissue physiological functioning by supporting corneal endothelial barrier integrity.
关键词： epidermal growth factor receptor,human corneal endothelial cells,mitogen‐activated protein kinase,pituitary adenylate cyclase–activating polypeptide
更新于2025-09-23 15:19:57
-
[Methods in Molecular Biology] Autoantibodies Volume 1901 (Methods and Protocols) || Determination of CRP Autoantibodies by SPR Immunoassay
摘要： Biosensors based on the principle of surface plasmon resonance (SPR) are surface-sensitive optical devices used for monitoring biomolecular interactions at the sensor surface in real time without any labeling. It is used in a wide variety of areas including proteomics, clinical diagnosis, environmental monitoring, drug discovery, and food analysis. C-reactive protein (CRP) is a marker of in?ammation, which undergoes conformation changes in local lesions, leading to the formation of mCRP. Autoantibodies against mCRP are frequently detected in systemic lupus erythematosus (SLE) and associated with disease activity and prognosis. An SPR immunoassay for CRP autoantibodies at complement factor H–CRP interface is described in this chapter.
关键词： Surface plasmon resonance,CRP,Immobilization,Complement factor H,CRP autoantibody
更新于2025-09-23 15:19:57
-
Single-molecule F?rster Resonance Energy Transfer Measurement Reveals Dynamic Partially Ordered Structure of the Epidermal Growth Factor Receptor C-tail Domain
摘要： Intrinsically disordered proteins (IDPs) or regions (IDRs) are thought to exhibit unique functionalities without forming ordered structures. However, these molecular mechanisms are not easily elucidated, partly because of the difficultly of measuring structural information. In this study, we applied the alternative laser excitation (ALEX) method and circular dichroism (CD) spectroscopy to investigate the structure of the C-terminal tail (CTT) domain of the human epidermal growth factor receptor (EGFR). The single-molecule distributions of F?rster resonance energy transfer (FRET) obtained by ALEX under solution conditions modified by the addition of potassium chloride (KCl), urea or guanidinium chloride (GdmCl) allowed us to separately examine the influences of charge interactions and secondary structure formation. The CD spectrum analyses indicated the types of included secondary structure. The results suggested that the structure of the CTT is influenced by secondary structure formation, which is principally antiparallel β-sheet, rather than by charge interactions, and that phosphorylation of the major Grb2-binding sites partially denature that secondary structure. Our findings suggest that the EGFR CTT might regulate ligand binding kinetics by local β-sheet formation or by the disruption associated with phosphorylation states.
关键词： Circular dichroism,Epidermal Growth Factor Receptor,F?rster resonance energy transfer,Secondary structure,Intrinsically disordered proteins
更新于2025-09-23 15:19:57