- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Effect of low-energy ion impact on the structure of hexagonal boron nitride films studied in surface-wave plasma
摘要： A high‐density surface‐wave plasma source is used to deposit hexagonal boron nitride (hBN) films in a gas mixture of He, H2, N2, Ar, and BF3 under a high ion flux condition using low‐energy ion irradiation. The ion energy is controlled between around zero and 100 eV by applying a negative or positive bias voltage to a substrate, while the ion flux is increased by locating a substrate upstream in the diffusive plasma. For ion energies above ～37 eV, the structure of the films depends upon ion energy more than substrate temperature, typical of subplantation processes. As a result, the structural order and crystallinity of sp2‐bonded phase in the films characterized by Fourier transform infrared spectroscopy and X‐ray diffraction are increased with decreasing ion energy, while the mass density of the films characterized by X‐ray reflectivity is retained relatively high with a slight dependence upon ion energy.
关键词： surface‐wave plasma,Fourier transform infrared spectroscopy (FTIR),chemical vapor deposition (CVD),hexagonal boron nitride (hBN),X‐ray diffraction (XRD),X‐ray reflectivity (XRR)
更新于2025-09-23 15:21:21
-
Schiff base rare earth metal complexes: Studies on functional, optical and thermal properties and assessment of antibacterial activity
摘要： We used the condensation chemistry with anthracene 9 carbaldehyde and 3,4 diaminopyridine to form Schiff base (SB) ligand, N2,N3 bis (anthracen 9 ylmethylene) pyridine 3,4 diamine incorporating Er, Pr and Yb rare earth metals to form a series of SB complexes. Surface, structure, thermal, and optical properties of the resulting complexes were investigated using a variety of tools. The characteristic luminescence properties were observed after rare earth metal inclusions in SB. Antibacterial studies were performed against Bacillus subtilis, Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa in terms of zone of inhibition for SB complexes. The SB-Pr complexes showed better immune behavior against all the pathogens than the other SB metal complexes.
关键词： Schiff base,Antibacterial,Rare earth metal,Fluorescence,Fourier transform infrared
更新于2025-09-23 15:21:21
-
Effect of substrate bias and substrate/plasma generator distance on properties of a-C:H:SiOx films synthesized by PACVD
摘要： In this paper the a-C:H:SiOx films were synthesized on silicon (100) and glass substrates by plasma-assisted chemical vapor deposition combined with pulsed bipolar substrate bias from mixtures of argon and polyphenylmethylsiloxane vapor. The process of a-C:H:SiOx films formation was investigated by controlling processing conditions such as amplitude of negative pulse of substrate bias and the distance between the substrate and plasma generator. Physico-mechanical characteristics of a-C:H:SiOx films were studied by the nanoindentation technique, atomic force microscopy, Fourier transform infrared and Raman spectroscopy. The contact angle and surface free energy were determined by the sessile drop method using couple liquids (water and glycerin). It was found that the films’ properties are interrelated with the density of the ion current on the substrate, which was measured using a guarded planar probe. The obtained results show that film prepared at the smaller substrate/plasma generator distance and optimal substrate biasing has a higher content of sp3 bonded carbon and, accordingly, has higher hardness, Young's modulus and resistance to plastic deformation. At the same time the a-C:H:SiOx films show large hydrophobicity with a contact angle for water of about 91° and small total surface free energy of about 17.9 mN/m.
关键词： a-C:H:SiOx films,PACVD,Raman Spectroscopy,Substrate bias,Fourier Transform Infrared Spectroscopy,Wettability
更新于2025-09-23 15:21:21
-
Transmission of Higher Order Solitons created by Optical Multiplexing
摘要： The nonlinear Fourier transform (NFT) is a promising tool to linearize the inherently nonlinear optical fiber channel. The NFT transforms a time domain signal into the continuous and the discrete spectrum. The discrete spectrum is composed of an arbitrary number of complex valued discrete eigenvalues and their associated amplitudes. These discrete eigenvalues relate to solitons, which maintain their shape or return to it in an oscillating manner, while passing through the optical channel. Higher order solitons consisting of multiple eigenvalues are complex pulses, which are created and demodulated by sophisticated digital signal processing (DSP) leading to demanding hardware requirements. This paper shows a way to work with higher order solitons in a WDM like fashion by using optical-electrical signal processing and presents boundaries of this method. Optical-electrical signal processing decreases the required electrical and electro-optical hardware specifications substantially and enables to use a simplified DSP. The proposed creation method is subsequently employed to transmit higher order solitons consisting of five QPSK modulated eigenvalues. Furthermore, the optical-electrical processing is benchmarked against the Darboux transformation, which creates higher order solitons purely numerically. The results show that for a 5th order soliton transmission the proposed method can significantly reduce the hardware requirements and DSP complexity.
关键词： solitons,nonlinear Fourier transform,optical signal processing,nonlinear optics,optical fiber communication,Darboux transform
更新于2025-09-23 15:21:01
-
[IEEE 2019 Photonics & Electromagnetics Research Symposium - Fall (PIERS - Fall) - Xiamen, China (2019.12.17-2019.12.20)] 2019 Photonics & Electromagnetics Research Symposium - Fall (PIERS - Fall) - Simulation of Full Responses of Triaxial Induction Logging in 1D Layered Arbitrarily Anisotropic Formations
摘要： Triaxial induction tools can be used to evaluate thinly laminated sand-shale sequences and fractured beds. This type of reservoirs exhibit transversely isotropy (TI) or arbitrarily anisotropy (also called as biaxial anisotropy (BA)). There have been several papers to study the responses in the TI model or the simpli?ed BA model whose conductivity principal coordinate is always consistent with the formation coordinate. However, little work covers the most general biaxial anisotropic model whose conductivity tensor’s orientation is arbitrary. We introduce the Euler angles, then the general biaxial anisotropic conductivity tensor can be determined by three principal components and three ordered Euler angles. To derive the electromagnetic (EM) ?elds in arbitrarily anisotropic medium, we ?rst convert the Maxwell’s equation of frequency-spatial domain into frequency-wavenumber domain by 2D Fourier transform, and obtain an ordinary di?erential system about horizontal components of EM ?elds. Using eigenvalue decomposition of the system matrix, this system can be decomposed into two group of equations associated with upward and downward eigen-waves respectively. We derive the solutions of EM ?elds in frequency-wavenumber domain by introducing transmission matrix, both local and generalized re?ection matrix and propagator matrix After that, we use 2D Gauss-Legendre quadrature to calculate inverse Fourier transformation and obtain Green’s function for simulation of the tri- axial induction responses. The numerical results are compared with 3D numerical method in both vertical and deviated wells and the agreement is satisfactory. Finally, we investigate the response characteristics in several formations with di?erent Euler angles The results show that triaxial induction responses are remarkably in?uenced by Euler angles even if the values of three principal components of conductivity tensor remain unchanged. Compare to the responses of the simpli?ed BA model, those of general BA model are more complex and contain more nonzero components. The results indicate that using TI model or the simpli?ed BA model in complex environment may cause large errors. Our algorithm are more practical than algorithms based on the simpli?ed model because the real depositional environments are usually complicated.
关键词： Maxwell’s equation,biaxial anisotropy,eigenvalue decomposition,Triaxial induction logging,Euler angles,Fourier transform,Gauss-Legendre quadrature
更新于2025-09-23 15:21:01
-
Handheld pocket-size Fourier transform profilometry using projector-enabled smartphone
摘要： Surface Fourier transform profilometry (FTP) is a technique used for reconstructing three-dimensional (3-D) surface topography using light. It has been widely used in machine vision for biomedical and biometric automations, providing solutions beyond conventional 2-D imaging. This paper proposes an implementation of the handheld pocket-size FTP for 3-D surface profile imaging using a projector-enabled Samsung Galaxy Beam smartphone. In the implementation, a crossed-optical-axes geometry of the FTP is formed by using a mirror positioned over the phone’s projector via an adjustable tilt mounting bracket. Experimental proof-of-concept of the proposed profilometry is done by implementing conventional and non-phase shifting FTPs with different diffuse test objects. The experimental results obtained by using the non-phase shifting technique are in good agreement with those of the direct contact measurement. Besides having superiority of compactness, the proposed profilometry paves the way for the development of real-time 3-D profiling and printing through internet or Bluetooth interconnection.
关键词： 3-D profilometry,non-phase shifting technique,contrast function,sinusoidal grating,projector-enabled smartphone,3-D surface topography,Samsung galaxy beam,Fourier transform,shape measurement
更新于2025-09-23 15:21:01
-
Thulium fiber laser: ready to dust all urinary stone composition types?
摘要： Purpose To evaluate whether stone dust can be obtained from all prevailing stone composition types using the thulium fiber laser (TFL) for lithotripsy. Where applicable, stone dust was further characterized by morpho-constitutional analysis. Methods Human urinary stones were submitted to in vitro lithotripsy using a FiberLase U2 TFL generator with 150 μm silica core fibers (IPG Photonics?, IPG Medical?, Marlborough, MA, USA). Laser settings were 0.05 J, 320 Hz and 200 μs. A total of 2400 J were delivered to each stone composition type. All evaluated stones had a > 90% degree of purity (calcium oxalate monohydrate, calcium oxalate dihydrate, uric acid, carbapatite, struvite, brushite and cystine). Spontaneously floating stone particles were considered as stone dust and collected for analysis by scanning electron microscopy and Fourier transform infrared spectroscopy. Results Stone dust could be retrieved from all evaluated urinary stones after TFL lithotripsy. Most stone dust samples revealed changes in crystalline organization, except for calcium oxalate monohydrate and carbapatite, which conserved their initial characteristics. Mean maximal width of stone dust particles did not exceed 254 μm. Conclusions The TFL is capable to produce stone dust from all prevailing stone types. Morpho-constitutional changes found in stone dust suggest a photothermal interaction of laser energy with the stone matrix during TFL lithotripsy.
关键词： Urolithiasis,Stone dust,Fourier transform infrared spectroscopy,Lithotripsy,Scanning electron microscopy,Thulium fiber laser
更新于2025-09-23 15:21:01
-
Roughness of surface decorated with randomly distributed pillars
摘要： We have presented a quantitative analysis of roughness of planar surfaces decorated with randomly distributed, cylindrical pillars, disks, or cavities. We have described the roughness in terms of the surface power spectral density (PSD). First, we have derived a general equation for the PSD of such surfaces. Then, we have found the PSD for the special case of statistically isotropic, circular areas. We have demonstrated that the PSD provides quantitative information on the radius of the circular area, dimensions of the pillar, and surface coverage. We have also discussed the numerical method of extracting the parameters from experimental PSD data obtained from discrete Fourier transform of surface scanning measurements.
关键词： Fourier transform,cylindrical pillars,surface roughness,random distribution,power spectral density
更新于2025-09-23 15:21:01
-
Indirect predissociation of highly excited singlet states of N <sub/><b>2</b> </sub>
摘要： Indirect predissociation of the b(cid:2) 1(cid:1)+u (v = 20) level of N2 is studied experimentally by vacuum-ultraviolet photoabsorption employing synchrotron radiation and a Fourier-transform spectrometer, and interpreted with the aid of a quantitative model of interacting 1(cid:2)u and 1(cid:1)+u, bound and unbound states which solves the coupled Schr?dinger equation. An observed rotationally-localised peak in the b(cid:2)(20) predissociation linewidths is identi?ed by the model as arising from an interaction with a strongly predissociated and unobserved bound level of the mixed c3 1(cid:2)u and o3 1(cid:2)u Rydberg states. This leads to the dissociation of b(cid:2)(20) into the continuum of the b 1(cid:2)u valence state. The residual observed predissociation of b(cid:2) 1(cid:1)+u (v = 20) apart from the rotationally-localised peak cannot be explained by a mechanism of 1(cid:2)u and 1(cid:1)+u interaction, and must involve states of higher multiplicity.
关键词： Fourier-transform spectrometer,coupled Schr?dinger equation,vacuum-ultraviolet photoabsorption,N2,Indirect predissociation,synchrotron radiation
更新于2025-09-23 15:21:01
-
Estimation of Data Hiding Capacities in Spatio-Chromatic Fourier Transform (SCFT) Representations of Color Images
摘要： Despite the abundance of color images, a vast majority of digital image watermarking algorithms are specifically designed for gray-scale images in terms of perceptual modeling, watermark embedding and data hiding capacity. This paper tries to bridge this gap and provides information theoretic estimates of data hiding capacities for standard color images using an improved version of the CIEL*a*b* color space. These capacity estimates are derived based on appropriate color models of the spatio-chromatic Fourier transform (SCFT) of the host image, distortion constraints imposed on the watermarking game players (watermark embedder and attacker), and side information available to both players. This paper considers full-frame and block-based SCFT statistical representations for color images and derive data hiding bounds for these image sources assuming invariance to affine and geometric attacks. Finally, the estimated data hiding capacities are used to assess the performance of a color-based SCFT image watermarking algorithm. The performance results highlight the importance of combining the estimated hiding capacities and perceptual model in designing a high capacity, robust and perceptual color image watermarking system.
关键词： Spatio-chromatic Fourier transform (SCFT),Watermarking games,Color image watermarking,Data hiding capacity
更新于2025-09-23 15:21:01