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The potential dynamic risk of the mined underground space with hard overlying strata is one of the main concerns for coal operators. This paper presents a comprehensive study on treating the hard overlying strata upon the coal seam through the presplit blasting technique. The properties of the overlying strata were firstly investigated and evaluated via the laboratory tests and theoretical analysis. With the consideration of the geological and mining condition of the research area, the critical parameters of the presplit blasting technique (e.g., unsaturation coefficient, borehole spacing, and the slit width) were consequently determined via the numerical simulation with the application of LS-DYNA. Then, the field practice in accordance with the determined parameters was carried out in Yuwu coal mine. The effectiveness of the presplit blasting technique was well verified when the microstructures of the surrounding rock were investigated. The success presented in this paper does not only demonstrate the feasibility of using the presplit blasting technique in treating the hard strata of underground mines but also provide a guideline in determining the critical parameters by the numerical simulation and theoretical analysis from the design aspect.

A slit structure consisted of two bending graphene membranes is built as a nano check valve theoretically. Molecular dynamics simulations are used to investigate the opening and closing of this check valve. The backflow through the valve are also studied. The results show that the check valve can maintain the unidirectional flow of fluid and prevent backflow within the appropriate pressure range. Specifically, the opening and closing pressure of the valve are 148.2 and 24.6 MPa, respectively. The maximum working pressure of the check valve should be lower than 197.6 MPa. Moreover, the water passing rate is larger at a higher pressure due to the larger slit width and water flux. This check valve is expected to have many potential applications in the nanofluidic field.

Background It has always been a great challenge for clinical doctors to reconstruct total and near-total lower lip defects. Compared with elderly patients, the repair operation in young patients is more difficult where free flaps are usually used for transfer. In order to obtain better postoperative results, the authors combined two kinds of local skin flaps for operation purpose, and evaluated their postoperative clinical effects. Methods From April 2011 to May 2019, a total of 5 young patients with lower lip tumor or trauma were included in this study, with an average age of 30.4 years old. The lesion was all resected and resulted in a defect of 87% to total area of the lower lip, accompanied by a partial defect of the chin each. To repair the defect of the lower lip, the authors firstly used the modified Bernard flap. Then the authors designed the double Abbe flap to perform the operation according to the recovery of the patient 3 months later than the first operation. Finally, the outcomes of either operation were compared upon slit width, mouth opening height, aesthetics, and function of the patients, and statistically analyzed the results. Results All patients underwent the repair of modified Bernard flaps and double Abbe flaps of with no hemodynamic disorder of the flaps and well-recovery. At 3 months after the operation, the average gap width of lip was 4.34 ± 0.24 cm, the average opening height was 3.18 ± 0.28 cm, the average aesthetic score was 7.98 ± 0.51 (full score of 10), and the average functional score was 11.4 ± 0.55 (full score of 12). The 5 patients showed no obvious scar but a good shape on the lower lip. The function of eating, pronunciation, expression of feelings and smiling change were close to normal. Three patients had mild numbness in the lower lip, while the other two had normal sensory function. Conclusion Combined modified Bernard flap and double Abbe flaps can bring out promising reparative outcomes of near-total or total lower lip defects in lower lip in young patients with good aesthetic and functional recovery, which is recommended while considering surgical alternatives.

PURPOSE After many years in clinical practice, the authors found that the long-term aesthetics of the upper lip and nose following repair of a unilateral cleft lip deformity using the Huaxi method remained unsatisfactory. The immediate postoperative effect was often good, while the long-term postoperative effect was poor. Therefore, this study aimed to evaluate the characteristics and influencing factors of a modified Huaxi method for repairing unilateral cleft lip over time, and to explore the relationship between immediate and long-term outcomes after cleft lip surgery. METHODS Patients with unilateral cleft lip who visited the Department of Maxillofacial Surgery of the Stomatological Hospital of Zunyi Medical University from June 2014 to March 2016 were selected. The study group consisted of 51 consecutive patients (30 boys and 21 girls), aged between 3 months and 2 years. Of these, 24 presented with complete unilateral cleft lip (12 wore a nasoalveolar mold as required, 12 did not) and 27 with incomplete unilateral cleft lip (13 wore a nasoalveolar mold as required, 14 did not). Photographs were taken of 51 patients before surgery and immediately, 7 days, and 6 months postoperatively. Various indexes of nasolabial contour of each patient were measured using iWitness photogrammetry, and the slit width; lip height ratio, lip width ratio, nostril width ratio, and nostril height ratio of the healthy side; and degree of deviation of the nasal columella were calculated. RESULTS Long-term symmetry of lip height and width remained stable postoperatively (P > 0.05), whereas nostril height symmetry was significantly reduced (P > 0.05). Nasal width symmetry and midpoint deviation of the nasal columella were stable in patients with nasoalveolar molding (P > 0.05), but significantly decreased in patients without nasoalveolar molding (P

Two specimens of nonductile reinforced concrete (RC) frame (ND-1) and nonductile RC frame retrofitted by corrugated steel plate shear walls slotted with columns (ND-2) are established by finite element. These specimens have same dimensions and steel skeletons. Finite element models had been verified by the existing experimental results. The hysteresis curves, skeleton curves, ductility, and stiffness curves of Specimen ND-1 and Specimen ND-2 are compared. The results show that the reinforcement effect is significant. Twenty-four models are built to study the seismic behavior on different influence parameters. The parameters are slit width, thickness of corrugated steel plate shear walls, concrete strength of nonductile RC frame, and boundary conditions of corrugated steel plate shear walls at slotted parts. The results indicate that the strength is declined with the increase of slit width. With the increase of thickness and concrete strength, the strength and stiffness are enhanced. The strength is larger with the boundary than without. Slit width and thickness have an important impact on the stiffness. Concrete strength and boundary conditions have little impact on stiffness. The strengthened nonductile RC frames have enough ductility.

We proposed a promising method for fabricating elliptical microlens and microlens array with controlling morphology by slit-based spatially shaped femtosecond laser-assisted chemical etching on fused silica (SiO2). The major axis length and the ratio of major and minor axis were controlled by changing the slit width. The minor axis length was controlled by changing the energy. This method had good flexibility and high efficiency. The convex elliptical microlens and microlens array were also realized by mold replication.

The luminosity of lightning channel is closely related to the lightning current. In the present paper, a lightning channel luminosity detection system (LCLDS), comprising of an avalanche photodiode module, a neutral density filter, an extension tube and an adjustable horizontal slit, is assembled. By using the impulse current generator, lightning impulse currents with different amplitudes and also different waveforms were produced in a 15-mm open-air gap between two graphite-rod electrodes. The luminosity and the current of discharge channel were measured synchronously. The experiments looking into the influencing factors of luminosity measurement, including the alignment of the silt and the slit width, were carried out. Obtained results show that the slit opening center of LCLDS should be aligned to the center of the discharge gap. Otherwise, in the case of improper alignment, the measured luminosity waveforms associated with the same injected current might be quite different in the amplitudes as well as in the waveforms. Moreover, the peak luminosity increases linearly with increasing slit width, whereas the luminosity waveforms are practically unaffected, implying that, in the practical application, the slit width can be adjusted to alter the luminosity signal output according to the actual need. Obtained results here can establish the foundation to develop the correlation between the current and the corresponding luminosity in the future.

We demonstrate that the interference pattern of the plasmonic and photonic modes can be controlled by changing the slit width of a square slit structure. Based on the analyses of the plasmonic and photonic modes of slits with different widths, we theoretically derived the expressions of wavefield generated by a square slit. A far-field scattered imaging system is utilized to collect the intensity distribution experimentally. Various interference patterns, including stripes, square-like lattice array, and diamond-like lattice array, have been observed by adjusting the slit widths. In addition, the results were validated by performing finite-difference time-domain simulations, which are consistent with the theoretical and experimental results.

Time-gated Raman system has been assembled using a pulsed laser and high-resolution echelle spectrograph. Echelle spectrograph provides broad spectral band-pass of 0–8500 cm�1 in a single scan with a resolution of 1.75 cm�1 for 532 nm at an extremely small slit width of 10 μm. Advantages of gated mode detection over continuous-wave mode detection are improved signal-to-noise ratio, reduced background signal, and unwanted fluorescent emission. Feasibility of echelle spectrograph for Raman measurements has been tested for both conventional and standoff distance of 5 m with all the external illumination sources on. The echelle system provides high-quality Raman signals with an extremely low inherent bandwidth in solid and liquid samples, (~8 cm�1 ) for 478 cm�1 fundamental band of sulfur. Intensity ratio of e2 fundamental to a1 fundamental of conventional and remote Raman measurements indicates that the spectral features remain the same in both measurements. The advantages of ‘time-gated’ Raman compared with continuous-wave mode detection, like low background even under extraneous illumination and lowered fluorescence, are also illustrated with spectrum of sulfur taken in the two modes.

The visual control of pecking by pigeons (Columba livia) has latterly been thought to be restricted to the fixation stops interrupting their downward head movements because these stops prevent interference by motion blur. Pigeons were also assumed to close their eyes during the final head thrust of the peck. Here we re-examine their pecking motions using high-speed video recordings and supplementary provisions that permitted a three-dimensional spatial analysis of the movement, including measurements of their pupil diameters and eyelid slit width. The results confirm that pigeons do not close their eyes completely during the presumed optically ballistic phase of pecking. Instead their eyelids are narrowed to a slit. The width of this slit is sensitive to both the ambient illumination levels and the visual backgrounds against which seed targets have to be detected and grasped. There is also evidence of some interaction between pupil diameter and eyelid slit width. We surmise that besides being an eye-protecting reflex, the partial covering of the pupil with the eyelids may increase the depth of focus, enabling pigeons to obtain sharp retinal images of peck target items at very close range and during the beak-gape ‘handling’ of food items and occasional grit particles.

In this paper, a three-dimensional numerical model of H-type finned tube heat exchangers has been built. In order to optimize its structure and improve its performance, Taguchi method is applied to investigate the influence of seven geometric parameters including slit width, row number, fin height, spanwise tube pitch, longitudinal tube pitch, fin thickness and fin pitch. Numerical simulations are performed on eighteen cases with different combinations of seven geometric parameters and the overall thermal–hydraulic performance and its characteristics of heat transfer and flow friction are discussed in detail. The results show that fin pitch and fin height play a significant role on the heat transfer characteristics while the flow friction characteristics are mainly affected by fin height, spanwise tube pitch and fin pitch. The intuitive analysis and analysis of variance show that fin pitch, fin height and fin thickness have much stronger influence on its overall thermal–hydraulic performance than the rest four parameters. Finally, the optimal parametric combination of the H-type finned tube is obtained with an improvement of overall thermal–hydraulic performance by 11.4–16% for Re in range from 9000 to 24,000.

Recently, Panuski and Mungan presented the results of their study of light diffraction from a variable-width single slit by observing and measuring the diffraction pattern on an observation screen placed at a fixed distance. In this way, the authors were able to demonstrate to students the important near-field effects for single-slit diffraction, which most often have been neglected in introductory courses. In this paper, we show that there exists very good agreement between observed data and theoretical calculations by plotting intensity from single slits using a method with Fresnel-Kirchhoff integrals (Fig. 1). In addition to these comparisons, and with the evaluation of the Fresnel numbers, we argue that Panuski and Mungan demonstrated not only the near-field Fresnel, but also the far-field Fraunhofer regimes as well as the transition between the two. Furthermore, with a greater increase in the slit width, the transition to the geometric regime can be demonstrated (Fig. 2).

We present analytical solutions for the principal maxima in multiple slit diffraction. By expanding the angular position of the principal maxima in orders of a / d where d is the distance between two adjacent slits and a is the width of each slit, we obtain the angular position of the principal maxima up to the twelfth order in a / d .

Comprehensive investigations of electromagnetic enhancement and transmittance by a periodic array of gold nano-slits are presented. Rigorous numerical data can be well predicted by a simple Fabry–Perot model. By virtue of the model, the role of Fabry–Perot resonance that enables giant electromagnetic enhancement and high transmittance by a gold nano-slit array is studied. Distinct impacts of array period and slit width on electromagnetic enhancement and those on transmittance are explored. Numerical results imply that contributions of electromagnetic enhancement and transmittance should be considered together in determining the actual enhanced effect of sample signals in surface-enhanced Raman scattering application.

We perform a Young’s double-slit experiment using a partially-coherent light source. As compared to the standard theory, the data agree much more favorably with a calculation that fully accounts for the width of the slits.

An experimental study on the thermal performance of slit-glazed collectors was conducted. Here, glass panes were used as slit glazing cover, and the air was blown continuously through the gaps between them by fan (slit glazing is an uncomplicated and economical process compared to glass perforation). In this study, the effect of the width of glass panes, the distance between the slits, and mass flow rates were studied on three slit-glazed collectors. A glass pane with the length of 131 cm and thickness 0.4 cm was studied for three different slit widths: 6, 5, and 4 cm. The experiments are conducted with four different gap distances between the glass panes (0.5, 1, 2, and 3 mm) and three air mass flow rates (0.014, 0.022, and 0.029 kg/s). The experimental results indicated that the maximum thermal efficiency of 75% was obtained when the gap distance was 0.5 mm, slit width was 4 cm, and the mass flow rate was 0.029 kg/s. The maximum rise in air temperature was noted as 28°C when the gap distance and slit widths were 0.5 mm and 5 cm, respectively. Hence, the best thermal performance was achieved with the smallest slit width and gap distance parameter values.

An approach has been developed to calculation of the Irving-Kirkwood pressure tensor inside a circular plane-parallel empty slit between bodies with dispersion forces. The disjoining pressure is determined as the normal component of the pressure tensor on a slit wall and is found as a function of both the width and radius of the slit. It has been shown that, at a preset slit width, the disjoining pressure acquires a value almost equal to that inherent in an infinitely long slit already at a circular slit radius five times larger than the slit width.

X-ray diffraction analysis is a convenient and important route to investigate crystalline materials. With powder materials, calcium carbonate as target, the effects of scatter slit, soller slit and receiving slit of Bruker D8 ADVANCE diffractometer on the diffraction pattern based on information, such as the background intensity, peak height, intensity and full width at half maximum, which provide the evidence for slits selection.

Theoretical simulation and experiments based on a prism beam expander and an echelle grating are conducted to study the dependence of linewidth and pulse energy on incidence angle and slit width. With a larger prism incident angle or narrower slit width, the linewidth becomes narrower while the laser pulse energy becomes lower. However, the pulse energy can be improved by optimally designing the prism beam expander. In addition, a subpicometer linewidth ArF laser is obtained with a double-prism beam expander and an echelle grating.

The images of a metal plate with a slit are obtained under various observation angles, by means of the method of moment and fast backprojection algorithm. Meanwhile, the impact on slit diffraction of edge diffraction and corner diffraction is eliminated through low reflection carrier design, image capture and RCS reconstruction method. Then, the slit RCS on a metal plate versus incident angles is given, and the variation of the slit RCS on a metal plate versus frequency, polarization, slit width and plate thickness are analyzed, which provides a basis for the low reflection target RCS prediction and suppression.

Double-slit imaging is widely used for verifying the resolution of high-resolution and super-resolution microscopies. However, due to the fabrication limits, the slit width is generally non-negligible, which can affect the claimed resolution. In this paper we theoretically calculate the electromagnetic field distribution inside and near the metallic double slit using waveguide mode expansion method, and acquire the far-field image by vectorial Fourier optics. We find that the slit width has minimal influence when the illuminating light is polarized parallel to the slits. In this case, the claimed resolution should be based on the center-to-center distance of the double-slit. MOE (Min. of Education, S’pore) Published version

X-ray diffraction analysis is a convenient and important route to investigate crystalline materials. With mesoporous materials, Al-SBA-15 as target, the effects of scatter slit, soller slit and receiving slit of Bruker D8 ADVANCE diffractometer on the small-angle diffraction pattern based on information, such as the background intensity, peak height, intensity and full width at half maximum, which provide the evidence for slits selection.

Microarray technology has emerged as a major player in the parallel detection of biomolecules, but it still suffers from fundamental technical problems. Theoretical analysis of the printing process is crucial to achieve high quality microarrays. In this paper, modelling and hydrostatic analysis of contact printing microarrays by quill pins are presented. First, a complete contact printing process was modelled and divided into four stages: sample dipping, sample transferring, contact printing and spot spreading. Then, the hydrostatics mathematical model of each stage was developed. Based on the model analysis, the printing stability and continuity criteria and key parameters were described quantitatively. The results show that the slit width in the pin tip, the slit inclination and contact angle of quill pins have dominant effects on the stable and continual printing process. Finally, the quill pins were optimally designed and manufactured. A robotic microarray fabrication system using the quill pins was successfully developed and used to produce protein microarrays for biological applications.

Miniaturisation of metallic structures has become a prime issue and to meet high demand, modern fabricators extensively use different micro machining techniques. Wire electrochemical machining (wire ECM) is such a process of removing excess material electrochemically. However, the process is still new and further research is needed. Hence, the present work aims in developing suitable wire ECM setup to find out the influence of wire feed rate at varying voltage settings on corresponding width of the generated microslits. For this, experimentations have been carried out with 50 μm dia tungsten wire and machined micro features have been carefully observed under optical microscope. Additionally, the experimental results have been represented graphically where the minimum average width of the microslit is found to be 83.117 μm with an aspect ratio of 1.2. Moreover, complex microfeature with varying width has been fabricated by changing corresponding feed values in a single run.

Purpose To evaluate a custom-made ocular fluorometer for detection of intensity of light scatter (ILS) from the anterior chamber (A/C) as an objective measure of aqueous flare. Methods The fluorometer, equipped with a lock-in amplifier, was employed in the scatter mode to detect ILS from A/C. Measurements were performed with two illumination slit widths of 0.5 and 0.25 mm. The axial resolution at these slit widths were 80 and 200 μm, respectively. Healthy and pseudophakic eyes, with grade 0 Standardization of Uveitis Nomenclature (SUN) score, were employed as control subjects. ILS was also recorded in a cohort of patients who had undergone phacoemulsification and showed grades 1+ or 2+ on postoperative days 1 and 4. Results The inter- and intraobserver variabilities in the measurement of ILS were not significant. In cataract patients, ILS was significantly higher on postoperative day 1 relative to healthy eyes. By day 4, ILS decreased significantly and was only marginally different from ILS in quiet pseudophakic eyes or healthy eyes. Eyes with higher SUN scores showed proportionately increased ILS. The receiver-operator characteristic analysis indicated no advantage in using the smaller slit width in discriminating ILS at different SUN scores although it provided higher axial resolution. Conclusions The lock-in-based spot fluorometer is reliable for measurement of ILS with high precision and accuracy.The measured ILS correlates linearly with SUN scores and can be used to provide a higher granularity for recording aqueous flare. Translational relevance The instrument can be used in the clinical management of uveitis and drug development toward uveitis.

We provide measurements of Young’s double-slit experiment using a partially-coherent light source consisting of a helium-neon laser incident on a rotating piece of white paper. The data allow a quantitative comparison with both the standard theory that does not account for the width of the slits, and a full, analytic model that does. The data agree much more favorably with the full calculation.

Excel spreadsheets are used as an excellent tool in physics laboratory experiments related to wave optics. This paper presents a simple way to simulate diffraction of waves through a slit using Excel spreadsheets without any tedious programming. These simulations are used to visualize the effect of variation of different parameters such as number of slits, wavelength of incoming light, slit width and slit separation on Fraunhofer diffraction pattern.

This study investigates the influence of slit positions on the microclimate temperature/humidity of garments. To design the slits, a market survey was performed to indicate the method to apply the slits, in addition to a literature survey about muscles and body surface variation through body movements. Based on the survey, three positions of slits were selected, shoulder slit, lowback slit, and midback slit, a slit width of 1cm and length to 30cm was used. The results showed that microclimate temperatures/humidity on the back according to the slit positions were in the order of, lowback, midback, and the shoulder. The lowback slit showed the highest effect on the temperature/humidity of a front trunk. Lowback slits affected on localized areas of the glutaeus maximus, erector spinae, and latissimus dorsi. Midback slits affected the back muscle and deltoid. Shoulder slits showed a more significant effect on the localized area of the deltoid versus other localized areas. In the subjective sensations, the lowback slit was cooler, dryer, and more comfortable than the other slits. For the subjective sensations by fabric characteristics, the slit positions correlated at |r| and were significant at p

We present a procedure for measuring slit width and separation in single- and double-slit diffraction experiments. Intensity spectra of diffracted laser light are measured with an optical sensor (PIN diode). Slit widths and separations are extracted by fitting to the measured spectra. We present a simple fitting procedure to account for the integration (averaging) of light across the finite sensor aperture. This experiment provides students with a quantitative, in-depth verification of diffraction theory, as well as hands-on experience in sophisticated fitting methods.

The optical measurement of corneal thickness based on oblique viewing of the optical section of the cornea is complicated by the finite width of the incident slit beam. In this report the theoretical and practical aspects of the effect of the slit width on the thickness reading are analysed. In practice, it was not possible to make slit-width independent thickness readings which were reproducible from one observer to another. In addition, the observed slit-width error was found to vary from one patient to another. The lack of a reproducible estimate of the corneal thickness is attributed to difficulties associated with an exact definition of the edges of the visible bands of the optical section, which are determined by biological properties of the cornea as well as perceptive properties of the observer. Although inter-observer errors up to 0.02 mm were found, the intra-observer error amounted to only 0.005–0.006 mm (sd) between consecutive readings. Presumably this high intra-observer reproducibility is the result of the auxiliary pin-lights used. Changes in corneal thickness, measured by the same observer, can therefore be determined with great accuracy.

To solve the problem of excavation face dust control, the theory of dust removal after collection was put forward. Through a large number of theoretical and experimental researches, a new wind screen dust-collection system which was applied to comprehensive excavation face was developed. To set a wind dam in jet stream box, achieve the function of multi-stage and multiple-level regulation, lots of experimentation was carried out to obtain higher jet stream velocity with the minimum loss of energy. Experiments show that the slit width in the exports of wind screen dust-collection system should be 10 to 15 mm. For the general excavation roadway, after wind attenuation, the velocity can be greater than 3 m/s at the roof which meets the requirements of respirable dust control.

We theoretically demonstrate the formation of different kinds of two-dimensional split-ring arrays in both triangular and square lattices by one-step holographic interference. The slit width of the split-ring can be adjusted by proper polarization configurations. The dimension of the rings can be adjusted easily by using different wavelengths for interference, so the resonant frequency of the split-rings can be obtained in a wide range. Our theory is also proved in experiment. Our work would extend the application of holographic lithography to the fabrication of magnetic metamaterials., It will be very interesting to the nanofabrication, optical interference lithography and metamaterial communities

The wavelength shift of transmission resonance was achieved by a tapered metallic slit. We simulated the transmission and reflection of the tapered slit structure with the tapered slit width of 0.25, 0.5, 0.75 and 1 mm. The tapered slit angle shifted higher the resonance frequency, by which the cavity resonant length became shorter.

Arachnid strain sensitive slit sensilla are elongated openings in the cuticle with aspect ratios (slit length l/slit width b) of up to 100. Planar Finite Element (FE) models are used to calculate the relative slit face displacements, Dc, at the centers of single slits and of arrangements of mechanically interacting slits under uni-axial compressive far-field loads. Our main objective is to quantitatively study the role of the following geometrical parameters in stimulus transformation: aspect ratio, slit shape, geometry of the slits' centerlines, load direction, lateral distance S, longitudinal shift lambda, and difference in slit length Deltal between neighboring slits. Slit face displacements are primarily sensitive to slit length and load direction but little affected by aspect ratios between 20 and 100. In stacks of five parallel slits at lateral distances typical of lyriform organs (S=0.03 l) the longitudinal shift lambda substantially influences slit compression. A change of lambda from 0 to 0.85 l causes changes of up to 420% in Dc. Even minor morphological variations in the arrangements can substantially influence the stimulus transformation. The site of transduction in real slit sensilla does not always coincide with the position of maximum slit compression predicted by simplified models.

This paper describes an experimental work in order to assess the efficiency of slit dam on non-viscous debris flow. Some results have been acquired as follow: ① there are three kinds of blocking type: Total-blocking, opening and part-blocking. The blocking conditions of slit dam are closely link tob/d max (the ratio of slit width to maximum diameter of solid matter), asb/d max is less than 0.739, the slit dam is total-blocking; andb/d max is more than 1.478, the slit dam will be opening; whereasb/d max from 0.739 to 1.478, the slit dam is part-blocking. ② variation of the mean density passing through slit dam is the most obvious asb/d max ranges from 0.739 to 1.232. ③ According to experimental results, slit dams have been shown to be effective in reducing debris flow density while slit density ∑b/B (B is slit dam width) ranges from 0.2 to 0.5.

In this paper the phase singularities of the electromagnetic field near a sub-wavelength slit are studied. These phase singularities, such as optical vortices, are found in regular patterns, which can be created or annihilated under the conservation of certain topological quantities, when a parameter such as the slit width is changed. The connection between the phase singularities and the light transmission though the slit is considered.

We present a new technique to analyze the absorption efficiency of the active medium for a LD side-pumped Nd:YAG laser. A detailed ray trace has been carried out to evaluate the route of the pump LD-rays propagating inside the diffusing chamber. The method, named the infinite convergence approach, is used to determine the total absorbed power of a Nd:YAG rod when random reflection takes place at the inner surface of the reflector wall. By reason of losses caused by slits milled the reflector wall, there is an optimum slit width corresponding to the maximum absorption efficiency. It has been theoretically determined that the absorption efficiency can be summarized by a convergent result for the infinite energy transfer process inside the diffusing chamber. The method is applicable to the cavity design for any LD side-pumped solid-state lasers.

This paper presents a CCD camera-based system for slit width measurement of long precision slot dies. The slit width is calculated from the binary image of the slit after positions of the two edges of the slit are determined through a least square linear fitting of the edge data. The resolution of the CCD camera is on the order of sub-microns, which satisfies the requirement of quality control of the slit width. Local slit width can also be obtained because of the small field of view of the CCD camera. The slit width over the entire slot die can be measured enough scanning the CCD camera. The influence of the Z-directional straightness of the scanning stage can be reduced by choosing a proper threshold for binarization of the CCD image. Experimental results have shown that the slit width over the entire length of a 1.4 m long slot die can be measured in 33 seconds.

This paper describes experimental result of drag characteristics of the object with the slit. The test pieces are the column that the slit of straight, Y-type slit and clearance tapes were installed for the spiral rolls at 45. Slit width, Y-type opening angles, pitch of the spiral roll were changed. The Reynolds number is 60000. Using the smoke wind-tunnel facility, the flow visualization experiment processes image by the digital camera by the computer after the photographing.

本研究は, オープン型鋼製砂防ダムの鋼管間隔によって土石流中の礫をどのように捕捉するかについて, 個別要素法による数値シミュレーション解析を行うとともに, 確率的推定法の適用を試みたものである. すなわち, まず個別要素法によって土石流中の巨礫群の流れとオープン型砂防ダムによる閉塞シミュレーション法を提案した. 続いて, 待ち行列理論を応用して土石流中の巨礫群の礫径分布と砂防ダムの鋼管間隔比によって通過量期待値を求める方法を提案し, シミュレーション結果との整合性を調べた. その結果, 2個要素による閉塞モデルにおける通過確率期待値がシミュレーションとよく一致することを示した.

A new x-ray electron-optical converter with an Au or CsJ photocathode is described. The instrument has improved time resolution and improved image brightness. The slit width in the accelerating electrode can be chosen to be 50–100 μm. A working diagram of the converter is given.

The High Throughput Virtual Slit (or HTVS) is a new optical technology which can significantly increase the throughput and resolution of a dispersive spectrometer. The HTVS is able to preserve spectrometer etendue, mitigating photon losses normally associated with a slit. Originally implemented in multimode fiber-input spectrometers, HTVS has now been shown to be broadly applicable to a wide variety of spatially scanning hyperspectral imagers and standoff sensors, enhancing their performance and unlocking new application areas. In essence, the anamorphic elements of the HTVS optical system provide a means to decouple the spatial (iFOV) and spectral resolution of nearly any HSI system. In some scenarios, HTVS can be used to achieve better spectral resolution with the same input slit width. Alternatively, the slit can be widened (to increase the collected signal) while maintaining the same spectral resolution. This newfound flexibility in optimizing critical performance parameters not only improves the performance of HSI systems in existing remote sensing contexts, but also opens up numerous new application areas which were previously inaccessible to hyperspectral techniques. This method adds substantial value to existing HSI designs, particularly in applications involving targets with large spatial extent and requiring high spectral resolution (e.g. standoff Raman spectroscopy). We present recent experimental results from our prototype HTVS pushbroom imager and discuss case studies of standoff Raman detection of hazardous materials, passive detection of faint narrowband and monochromatic sources, and optimal disentangling of target spectral signatures from the solar spectrum under daytime illumination.

The final status of the optical design of the Russian–German soft-X-ray beamline at BESSY II is presented. Ray-tracing calculations provide the optimized parameters of the optical layout based on a Petersen-type plane-grating monochromator that operates with collimated light. Resolving power up to 25,000 and photon flux up to 3×10 10 photons/s/100 mA with a slit width of 20 μm will be available for spectroscopic experiments.

Using a setup based on fluorescence microscopy we study fluorescence spectra of single chromophores. Being point like emission sources single molecules can be focused to the entrance slit of a spectrometer. Even with narrow slit width the light passes the system with almost no loss. We show that, making full use of the emission properties of a single molecule, fluorescence spectra of many single molecules can be recorded simultaneously using (hyper-)spectral imaging. The vibrational frequencies of the single terrylene chromophores in naphthalene are the same within the accuracy of our experiments but the vibronic lines show pronounced differences in their relative intensities.

Raman analyses of the lifetimes of phonons in GaN and AlN crystallites of wurtzite structure are presented. In order to ensure the accuracy of the measurement of the phonon lifetimes, an experimental procedure to eliminate the broadening due to the finite slit width was performed. The lifetime analyses indicate that the phonon lifetimes in AlN as well as in GaN fall into two main time regimes: a relatively long time of the ${E}_{2}^{1}$ mode and much shorter times of the ${E}_{2}^{2},$ $E1(\mathrm{TO}),$ and $A1(\mathrm{TO})$ modes. The lifetimes of the ${E}_{2}^{1},$ ${E}_{2}^{2},$ $E1(\mathrm{TO}),$ $A1(\mathrm{TO}),$ and $A1(\mathrm{LO})$ modes of an high-quality AlN crystallite are 4.4, 0.83, 0.91, 0.76, and 0.45 ps, respectively. Moreover, the lifetime of the $A1(\mathrm{LO})$ mode found in this study is consistent with the current phonon-decay model of that mode in wurtzite structure materials. The lifetimes of ${E}_{2}^{1},$ ${E}_{2}^{2},$ $E1(\mathrm{TO}),$ and $A1(\mathrm{TO})$ of a GaN crystallite were found to be 10.1, 1.4, 0.95, and 0.46 ps, respectively. The $A1(\mathrm{LO})$ mode in the GaN was not observed and its absence is attributed to plasmon damping. The lifetime shortening due to impurities was also studied: the lifetimes of the Raman modes of an AlN crystallite, which contains about two orders of magnitude more Si and C impurities relative to the concentration of the high-quality crystallite were found to be 50% shorter.