Polished Plane Research Articles

Excitation of surface plasmon resonance with sodium-based photonic crystal fiber for sensing applications

Surface plasmon resonance (SPR) sensors using precious metal excitation have encountered bottlenecks in performance enhancement. To address this issue, we propose a photonic crystal fiber (PCF) sensor that utilizes a polymer-protected sodium film to excite the SPR effect. The PCF has hexagonally arranged air holes and a polishing plane. The sodium film is deposited on the polished plane and protected with polymethyl methacrylate or polydimethylsiloxane for refractive index sensing or temperature sensing. We analyzed this structure using the finite element method and found that the sodium-based SPR sensor has greater sensitivity, wider detection range, and higher figure of merit (FOM) than the SPR sensor using precious metal excitation. Numerical results showed that the maximum sensitivity was 35,400 nm/RIU, the widest detection range was 1.22–1.42, and the highest FOM was 3550RIU−1 at different sodium film thicknesses. When applied to temperature sensing, its maximum sensitivity is 20.5 nm/°C, and the temperature detection range is 0°C–100°C. In addition, our proposed sodium-based SPR fiber sensor is compatible with a thermo-assisted spin-coating process, so a good guideline scheme is available for the preparation. Therefore, our proposed sensor shows excellent potential in sensing and expands the application range of sodium-based plasma devices.

Ultrasensitive Strain Sensor Based on Core-Bending Long Period Fiber Grating

In this letter, a novel core-bending long period fiber grating (CB-LPFG) based on symmetrical polished fiber plane is designed and experimentally testified. By employing methods of CO2-laser polishing and oxyhydrogen flame heating, periodic bending cores are achieved on a symmetrical polished plane. Due to the reduction of the cladding and the bent core, the sensitivity of the structure is strongly enhanced. Experimental results present that the highest strain sensitivity of CB-LPFG with 7 periods reaches -0.846 nm/ <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \varepsilon $ </tex-math></inline-formula> . To the best of our knowledge, is firstly increasing the strain sensitivity of fiber sensor based on single-wavelength demodulation to nm/ <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \varepsilon $ </tex-math></inline-formula> level. Meanwhile, the temperature sensitivity of CB-LPFG is 236 pm/°C with dynamic range of 30- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$130~^{\circ }\text{C}$ </tex-math></inline-formula> . Consequently, the proposed sensor is expected to offer significant potential to detect micro-deformation more precisely.

A broadband SPR dual-channel sensor based on a PCF coated with sodium-silver for refractive index and temperature measurement

When temperature and refractive index are measured in same spectrum, the measurement range of parameters is generally narrow due to bandwidth limitation. We proposed a sensor for simultaneous measurement of them in a wide wavelength range for this problem. The proposed sensor is a dual-channel structure based on the photonic crystal fiber (PCF) with three air holes and a polished plane. The silver film deposited on the polished plane is responsible for refractive index measurement, and the sodium film and polydimethylsiloxane (PDMS) filled in an air hole for temperature measurement. According to research findings, the two kinds of metal films work in different wavebands, which increases the sensing bandwidth and the measurement range of the parameters to be measured. Numerical results show that when the refractive index of analyte is 1.35 ∼ 1.41 and the temperature is 10 ∼ 60℃, the maximum spectral sensitivity of the sensor is 8400 nm/RIU and 10.2 nm/℃, respectively. The results show that the performance of the sensor is not sensitive to structural parameters. It makes the sensor easy to manufacture. The excellent performances and wide detection range make the proposed sensor have a good application prospect in biochemical detection, environmental monitoring, medical sensing, and other fields.

High-performance all-fiber Mach-Zehnder interferometer based on D-shaped two-mode fiber coated with polydimethylsiloxane for temperature sensing

A novel fiber sensor, an all-fiber Mach-Zehnder interferometer based on D-shaped two-mode fiber (DTMF-MZI) coated with polydimethylsiloxane (PDMS), is proposed and demonstrated. When light is incident from a single-mode fiber (SMF) to a two-mode fiber (TMF), two modes will be excited in the TMF and interfere with each other, just like a two-beam fiber Mach-Zehnder interferometer (MZI). Due to the high negative thermo-optical coefficient, the proposed sensor is sensitive to temperature. Our theoretical analysis and experimental results prove that as the temperature increases, the dips in the transmitted spectrum of DTMF-MZI will blue-shift. Furthermore, we demonstrate the influences of the distance from the center of the fiber core to the polished plane (parameter h) and the length of the polished area (parameter Lpo) of TMF on the temperature sensitivity. In the experiments, the maximum temperature sensitivity of the proposed sensor reaches −305.6 pm/°C in the temperature range of 30 ∼ 80 °C, and the linearity is as high as 0.9890. In addition, the sensor shows good stability at 30 °C and 80 °C in 60 min with the maximum variations of 0.16 nm. The proposed sensor has many advantages, such as being highly temperature-sensitive, compact, and stable.

High-Sensitivity Refractive Index Sensing and Broadband Tunable Polarization Filtering Characteristics of D-Shaped Micro-Structured Fiber With Single-Layer Air-Holes and Gold Film Based on SPR

An easy-to-implement side-polished micro-structured fiber MSF)based on surface plasmon resonance (SPR) is proposed. The influence of fiber structure parameters on transmission performance is investigated by finite element method (FEM). The chemical stable gold is deposited on the side polished plane to provide the plasmonic material required for SPR. Ten cladding air-holes are used to confine light transmission and improve the coupling strength between the core mode and surface plasmon polaritons (SPP) mode. The optimization results show that the MSF integrates the characteristics of high refractive index (RI) sensing and broadband tunable polarization filtering. In addition, the RI detection range of the sensor can be further extended by depositing a <inline-formula><tex-math notation="LaTeX">$Si_{3}N_{4}$</tex-math></inline-formula> dielectric layer on the gold film. The RI detection range of the sensor with gold coating is 1.20--1.325 with the maximum sensitivity of 12,000 nm/RIU. The RI measurement range of the sensor with gold-<inline-formula><tex-math notation="LaTeX">$Si_{3}N_{4}$</tex-math></inline-formula> bilayer film can be extended to 1.20--1.37, and the maximum sensitivity is 10,000 nm/RIU. Furthermore, by changing the ambient RI of gold-coated fiber or the polishing depth of fiber, a broadband tunable filter with excellent performance can be obtained. Therefore, the proposed MSF not only has application value in the detection of biochemical liquid samples, but also has broad application potential in broadband communication networks, which is helpful to promote the development of miniaturization and integration of optical devices.

The Strain Rate Sensitivity and Creep Behavior for the Tripler Plane of Potassium Dihydrogen Phosphate Crystal by Nanoindentation.

As an excellent multifunctional single crystal, potassium dihydrogen phosphate (KDP) is a well-known, difficult-to-process material for its soft-brittle and deliquescent nature. The surface mechanical properties are critical to the machining process; however, the characteristics of deformation behavior for KDP crystals have not been well studied. In this work, the strain rate effect on hardness was investigated on the mechanically polished tripler plane of a KDP crystal relying on nanoindentation technology. By increasing the strain rate from 0.001 to 0.1 s−1, hardness increased from 1.67 to 2.07 GPa. Hence, the strain rate sensitivity was determined as 0.053, and the activation volume of dislocation nucleation was 169 Å3. Based on the constant load-holding method, creep deformation was studied at various holding depths at room temperature. Under the spherical tip, creep deformation could be greatly enhanced with increasing holding depth, which was mainly due to the enlarged holding strain. Under the self-similar Berkovich indenter, creep strain could be reduced at a deeper location. Such an indentation size effect on creep deformation was firstly reported for KDP crystals. The strain rate sensitivity of the steady-state creep flow was estimated, and the creep mechanism was qualitatively discussed.

Surface Plasmon Resonance Sensor Based on Side-Polished D-Shaped Photonic Crystal Fiber With Split Cladding Air Holes

We present and numerically characterize a side-polished D-shaped photonic crystal fiber (PCF) sensor based on plasmon. The coupling properties and sensing performance are investigated through the parameter study of metal thickness and polishing depth by the finite element method. With uniform metal evaporation, the metal–dielectric interfaces of the polished flat plane and inner surfaces of split first-cladding air holes can support two different kinds of surface plasmon polariton (SPP) modes. Each mode has its certain resonance wavelength, which is independent of polishing depth and side-polishing angle, and the resonance intensity of the two modes can be changed by polishing depth and the angle, respectively. In the process of measuring analytes with different refractive indexs (RIs), a two-axis detecting method has been presented to improve the sensitivity. The commercial PCF ESM-12 is used to fabricate the sensor probe with wheel-polishing system, and the experimentally detected data have a good agreement with theoretical simulation. As RI varies, both the resonance and intensity perform linear response with the sensitivity of $2.3319\times 10^{3}$ nm/RIU and –252.86%/RIU, respectively. By detecting the wavelength and intensity at the resonance, the two-axis method has obtained a sensitivity of 127.0902 CI/0.01RIU, which is 9% higher than the conventional method (116.595 CI/0.01RIU) that only measures wavelength shift. This study facilitates a new way for the analysis of D-shaped PCF sensor characteristics and provides a novel detecting method to improve the sensitivity of side-polished SPR sensor.

Au-ITO deposited D-shaped photonic crystal fiber polarizer with a micro-opening based on surface plasmon resonance

Most of the surface plasmon resonance (SPR) based photonic crystal fiber (PCF) polarization filters have been designed with gold film/wire despite the adhesion of gold to silica is uncertain. In this paper, we use a thin layer of indium-tin-oxide (ITO) in between the polished plane of the D-shaped PCF and gold (Au) film, which assists in adhering. By optimizing the designed parameter, the coupling between the surface plasmon polariton (SPP) mode and core mode is attained at 1.55 μm operating wavelength that ensures the filtering ability of the proposed fiber at C-band optical communication window. The performance characteristics of the filter are analyzed by full-vector finite element method (FEM). Numerical results reveal that the inclusion of ITO layer enhances the filtering performance by increasing the attenuation loss of the undesired polarization mode. In addition, owing to the sharp loss peak response, the full width half maximum (FWHM) is achieved of only 30 nm. Such small FWHM makes the proposed fiber promising as a perfect polarization filter at 1.55 μm. Moreover, we reported extinction ratio as high as 806.52 dB and maximum insertion loss only 0.33 dB. Such appealing performance makes this filter widely applicable in communication networks and integrated optical devices especially in the C-band optical communication window.

Air void analysis of hardened concrete by means of photogrammetry

The present study investigates the use of close-range photogrammetry for automated air void analysis of hardened concrete without contrast enhancement.First, polished plane sections of concrete with varying air contents were analyzed by photogrammetry. The data in the form of point clouds were processed to identify the air voids. Second, the same plane sections were subjected to traditional air void analysis by contrast enhancement. Results of both methods were compared.The method based on photogrammetry showed potential, but it could not capture the smallest air voids. Better camera resolution and/or methods to reduce noise in the point cloud are needed.

Calculating of the True Sizes and the Numbers of Spherical Inclusions in Metal

Observing inclusions on a polished plane, researchers do not see these inclusions directly, but only their cross sections. Meanwhile, the given size of a section can be obtained from the inclusions of different sizes. The true sizes of the inclusions and their quantities are hidden from the researchers. This paper proposes a new method for determining the size distribution of inclusions derived from the size distribution of their sections. The method based on mathematical statistics allows evaluating the true sizes and quantities of inclusions. A notable feature of the method is that it enables a researcher to derive the confidence sets for the distribution functions. A special technique for testing the method has been developed. Numerous tests have shown good adequacy of the method.

A Simple Construction of Electrochemical Liver Microsomal Bioreactor for Rapid Drug Metabolism and Inhibition Assays

In order to design a green microsomal bioreactor on suitably identified carbon electrodes, it is important to understand the direct electrochemical properties at the interfaces between various carbon electrode materials and human liver microsomes (HLM). The novelty of this work is on the investigation of directly adsorbed HLM on different carbon electrodes with the goal to develop a simple, rapid, and new bioanalytical platform of HLM useful for drug metabolism and inhibition assays. These novel biointerfaces are designed in this study by a one step adsorption of HLM directly onto polished basal plane pyrolytic graphite (BPG), edge plane pyrolytic graphite (EPG), glassy carbon (GC), or high-purity graphite (HPG) electrodes. The estimated direct electron transfer (ET) rate constant of HLM on the smooth GC surface was significantly greater than that of the other electrodes. On the other hand, the electroactive surface coverage and stability of microsomal films were greater on highly surface defective, rough EPG and HPG electrodes compared to the smooth GC and less defective hydrophobic BPG surfaces. The presence of significantly higher oxygen functionalities and flatness of the GC surface is attributed to favoring faster ET rates of the coated layer of thin HLM film compared to other electrodes. The cytochrome P450 (CYP)-specific bioactivity of the liver microsomal film on the catalytically superior, stable HPG surface was confirmed by monitoring the electrocatalytic conversion of testosterone to 6β-hydroxytestosterone and its inhibition by the CYP-specific ketoconazole inhibitor. The identification of optimal HPG and EPG electrodes to design biologically active interfaces with liver microsomes is suggested to have immense significance in the design of one-step, green bioreactors for stereoselective drug metabolite synthesis and drug metabolism and inhibition assays.

Ultrabroad Bandwidth Polarization Filter Based on D-shaped Photonic Crystal Fibers with Gold Film

An ultrabroad bandwidth polarization filter based on D-shaped photonic crystal fibers with gold film is proposed. The design of gold film deposited on the polished plane of the D-shaped photonic crystal fibers is benefit to generate multiple resonances between surface plasmon polaritons and photons. In our designed polarization filter, the resonant intensity in y-polarization direction is much stronger than in x-polarization direction. An ultrabroad bandwidth of exceeding 1 μm with extinction ratio better than -20 dB is obtained. The performance characteristics of the filter can be improved further by optimizing the structure parameters of the D-shaped photonic crystal fibers.

Magnetic properties and domain structures in Nd–Fe–B sintered magnets with Tb additive reacted and diffused from the sample surface

We investigated the magnetic properties and domain structures of Nd–Fe–B sintered magnets with a Tb additive reacted and diffused from the sample surface. We characterized these magnets using vibrating sample magnetometry, Kerr effect microscopy, and electron probe microanalysis. In the reacted sample (R-Tb) in this study, the Tb concentration was higher on its surface (∼30μm depth) and in its interior grain boundaries than inside the subsurface crystal grains. The saturation polarization (Js) was about 6% lower in the reacted sample than in the non-reacted sample (N-Tb); which should come from the Js decrease in the Tb-substituted regions in the R-Tb sample. The substitution greatly improved the coercivity (Hc) of the samples from 1.02 MA/m (N-Tb) to 1.72 MA/m (R-Tb). To understand the reason of this increase, we measured the domain widths (dD) from the near-surface region (5–10μm depth) of the polished R-Tb sample and from deeper below the surface in the R-Tb and N-Tb samples. The average dD from the near-surface region of the polished R-Tb sample was approximately 20% wider than the other polished planes, where the dD was about 1.0μm for both samples. In addition to considering the reasons for this coercivity enhancement, we used a novel step method to compare the demagnetization behaviors of the R-Tb and N-Tb samples. The R-Tb sample likely had enhanced coercivity mainly because of the difficulty of nucleating magnetic reversal portions. This difficulty was mainly caused by the enlargement of the anisotropy field (Ha=2K1/Js) because of the decrease in saturation polarization by the Tb diffusion and reaction. The ∼20% wider average dD on the R-Tb surface polished plane was also explained mainly by this Js decrease.

Improving the Sensitivity of Fiber Surface Plasmon Resonance Sensor by Filling Liquid in a Hollow Core Photonic Crystal Fiber

Inspired by the classic theory, we suggest that the performance of a D-shaped fiber optical surface plasmon resonance (SPR) sensor can be improved by manipulating the fiber core mode. To demonstrate this, we propose a novel fiber SPR sensor based on a hollow core photonic crystal fiber with liquid mixture filled in the core. The fiber sensor design involves a side-polished fiber with gold film deposited on the polished plane and liquid filling. Numerical simulation results suggest that by tuning the refractive index of the liquid mixture, the predicted sensitivity will be over 6,430 nm/refractive index unit for an aqueous environment, which is competitive for fiber chemical sensing. This optimization method may lead to an ultrahigh sensitivityfiber optical biosensor.

603 2相鋼の低温脆性破壊における第二相粒子の影響(OS4-1 オーガナイズドセッション《材料・組織と加工》)

Ferrite steels exhibits ductile-brittle transition in general even in cases bearing the second phase. Low temperature brittle fracture mechanism in two cases of two-phase steels; one is two-phase stainless cast steel bearing ductile austenite grains and the other is pearlite steel bearing brittle cementite plates. Two-plane observations consisting of SEM fracture surface observation and Optical/SEM/EBSD observation on the sectioned and polished plane to reveal microstructure and crystallographic feature was performed. The role of the second phase particle for cleavage fracture of bcc grains is discussed.

Petrographic, geochemical, and mycological aspects of Miocene coals from the Nováky and Handlová mining districts, Slovakia

Abstract Fungi have once again become a topic of interest to coal scientists in their roles as agents of maceral formation. Recent works have demonstrated that fungi occur in association with woody remains, resins, and cuticles in coalified materials of a variety of ages, in addition to coal-balls and compression–impression fossils, where they are already well known. These forms, however, have only been viewed as cross-sections along a polished plane. Assigning the fungi to family, much less determining which fungi they represent is very difficult in this orientation. Fungal identifications are necessary to the continuance of this research into the origin of coal macerals because of the need to know if macrinite begins to form prior to incorporation into the peat, which could be demonstrated by its association with symbiotic and parasitic, rather than saprophytic fungi. This study examines the fungal remains recovered from eight coal samples from Miocene-age coals in the Novaky and Handlova mining districts of Slovakia with the aim of making this distinction. These samples were collected in Slovakia as part of the US Geological Survey's World Coal Quality Inventory program and provided to the authors. The samples were processed using the O'Keefe technique for subbituminous coals and mounted for observation in transmitted light. Forms were identified using published works and consultation with a modern mycologist. Forms recovered through palynologic processing were compared to and correlated with forms seen in cross-section under reflected light.

Profile Measurement of Polished Surface with Respect to a Lattice Plane of a Silicon Crystal Using a Self-Referenced Lattice Comparator

A method is proposed for performing surface profile measurements with respect to a reference plane defined by the lattice plane of a silicon single crystal. In this method, a surface normal to a polished plane is detected using an optical autocollimator and the direction normal to the lattice plane is sensed by X-ray diffraction. The relationship between these planes can be determined if the polished plane is connected to the single crystal. In the measurement system, the mirror and the silicon single crystal are attached backto-back. A monochromatized synchrotron radiation X-ray beam is incident on the single crystal and two detectors are used to measure diffracted X-rays. An optical autocollimator placed near the mirror is used to monitor the inclination of the mirror. The normal direction of the crystal lattice plane is obtained from two diffractions from equivalent reciprocal lattice points. The normal to the mirror is taken to be the angle measured by the autocollimator when the two diffractions are observed. Test experiments have been performed using the self-referenced lattice comparator established at beamline BL3C of the Photon Factory, KEK. The proposed method is discussed by comparing the surface profile of the mirror measured with this system with that measured using a Fizeau interferometer.

3D porosity and mineralogy characterization in tight gas sandstones

Tight gas reservoirs exhibit storage and flow characteristics that are intimately tied to depositional and diagenetic processes. As a result, exploitation of these resources requires a comprehensive reservoir description and characterization program to identify properties which control production. In particular, tight gas reservoirs have significant primary and secondary porosity and pore connectivity dominated by clays and slot-like pores. This makes them particularly susceptible to the effects of overburden stress and variable water saturation. This paper describes an integrated approach to describe a tight gas sandstone at the pore scale in 3D. In particular, the primary and secondary porosity of a tight gas sandstone are identified and quantified in three dimensions using 3D X-ray micro-CT imaging and visualization of core material at the pore scale. 3D images allow one to map in detail the pore and grain structure and interconnectivity of primary and secondary porosity. Once the tomographic images are combined with SEM images from a single plane within the cubic data set, the nature of the secondary porosity can be determined and quantified. In-situ mineral maps measured on the same polished plane are used to identify different microporous phases contributing to the secondary porosity. Once these data sets are combined, the contribution of individual clay minerals to the microporosity, pore connectivity, and petrophysical response can be determined. Insight into the producibility may also be gained. This illustrates the role 3D imaging technology can play in a comprehensive reservoir characterization program for tight gas.

Exploring Thermal Spray Gray Alumina Coating Pore Network Architecture by Combining Stereological Protocols and Impedance Electrochemical Spectroscopy

Complex multiscale pore network architecture characterized by multimodal pore size distribution and connectivity develops during the manufacture of ceramic thermal spray coatings from intra- and interlamellar cracks generated when each lamella spreads and solidifies to globular pores resulting from lamella stacking defects. This network significantly affects the coating properties and their in-service behaviors. De Hoff stereological analysis permits quantification of the three-dimensional (3D) distribution of spheroids (i.e., pores) from the determination of their two-dimensional (2D) distribution estimated by image analysis when analyzing the coating structure from a polished plane. Electrochemical impedance spectroscopy electrochemically examines a material surface by frequency variable current and potential and analyzes the complex impedance. When a coating covers the material surface, the electrolyte percolates through the more or less connected pore network to locally passivate the substrate. The resistive and capacitive characteristics of the equivalent electrical circuit will depend upon the connected pore network architecture. Both protocols were implemented to quantify thermal spray coating structures. Al2O3-13TiO2 coatings were atmospherically plasma sprayed using several sets of power parameters, are current intensity, plasma gas total flow rate, and plasma gas composition in order to determine their effects on pore network architecture. Particle characteristics upon impact, especially their related dimensionless numbers, such as Reynolds, Weber, and Sommerfeld criteria, were also determined. Analyses permitted identification of (a) the major effects of power parameters upon pore architecture and (b) the related formation mechanisms.

Propagation characteristics of multi-coating D-shaped optical fibres

An equivalent refractive index mathematic model is presented according to the geometrical structure of multi-coating D-shaped fibres, and the analysis of the loss characteristics of this kind of fibre is given. The results indicate that the losses of the propagation modes in the fibre are related to the distance between the polished plane and the fibre core, and to the refractive index and the thickness of the polymer adhesive. This provides theoretical instructions for us to choose suitable parameters of fibre devices. Since the losses of propagation modes of different states of polarization are different, a multi-coating D-shaped fibre will possess polarization extinction characteristic.