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Development and Evaluation of an In-line and On-line Monitoring System for Granule Size Distributions in Continuous Roll Compaction/Dry Granulation Based on Laser Diffraction
摘要： Purpose Roll compaction/dry granulation is established in manufacturing of solid oral dosage forms and, within the context of continuous manufacturing, it has sparked interest as material is fed, processed, and ejected continuously while also providing large possible throughputs. However, this amount of material has to be adequately controlled in real time to assure quality. Methods This research aimed at monitoring the critical quality attribute granule size distribution in continuous roll compaction/dry granulation (QbCon?; L.B. Bohle, Ennigerloh, Germany) using in-line and on-line laser diffraction. The influence of varying process parameters and excipient formulations was studied and evaluated with the prospect of using this technique to develop control loops. For this purpose, residence time parameters were assessed. In- and on-line data was compared with off-line laser diffraction and dynamic image analysis data. Results The system successfully monitored the granule size distribution in a variety of process parameters and throughputs (up to 27.5 kg/h). It was sensitive to changes in process parameters and changes in material blends, which could pose a potential threat to the final drug products’ quality. Average event propagation time from the compaction zone to the laser diffraction system of 17.7 s demonstrates the systems’ fast reaction time. Conclusion Results highlight laser diffraction as a valuable method of in- and on-line size determination and allow for the development of a control strategy using this principle.
关键词： Process analytical technologies,Laser diffraction,Continuous manufacturing,Roll compaction/dry granulation,Process monitoring
更新于2025-09-23 15:19:57
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Characterization and correlation of microstructure and hardness of Tia??6Ala??4V sheet surface-treated by pulsed laser
摘要： A hot-rolled Tie6Ale4V (Ti-64) sheet was surface-treated by pulsed laser at two different powers (100 and 200 W), with microstructural features and hardness before and after the laser surface treatment (LST) systematically investigated. Results show that after the LST at both powers there are two modi?cation zones with distinct microstructural characteristics: melted zone (MZ) near the laser beam center, completely composed of ?ne martensitic plates with dense {10e11} nanotwins inside them; heat-affected zone (HAZ) far away from the laser beam center, comprised of mixed structures of short-rod b particles, martensitic plates and untransformed bulk a grains. Hardness measurements reveal that the hardness of the Ti-64 sheet can be markedly increased (especially in the MZ) after the LST. In-depth analyses suggest that the hardness increase in the MZ can be ascribed to combined contributions from grain re?nement, presence of nanotwins and solid solution of alloying elements, while only the structural re?nement by ?ne plate structures contributes to hardening in the HAZ. Comparisons between both the LSTed specimens reveal that increasing the laser power from 100 W to 200 W can effectively enlarge the laser-modi?ed zones (both the MZ and the HAZ) and simultaneously re?ne plate structures, leading to further hardness increase.
关键词： Ti-6Ale4V,Hall-petch relation,Hardness,Electron backscatter diffraction,Pulsed laser
更新于2025-09-23 15:19:57
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X-ray emission from layered media irradiated by an x-ray free-electron laser
摘要： This article presents a computational study of the x-ray ?uorescence induced by the irradiation of thin layered media by intense, short x-ray pulses. The treatment is based on a numerical solution of the Helmholtz wave equation both for the pump and for the ?uorescence signal. Consistently with a possible heating of the medium during the x-ray pulse, complex refractive indices are calculated at each time step from the results of an underlying treatment of atomic physics. In the context of an important core-hole production as a result of photoionization, we discuss the peculiarities of the resulting ampli?ed ?uorescence grazing emission and of the Bragg diffraction which can be realized at some angles inside a multilayer material or even in a perfect crystal.
关键词： multilayer material,x-ray fluorescence,Bragg diffraction,complex refractive indices,photoionization,perfect crystal,Helmholtz wave equation
更新于2025-09-23 15:19:57
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Interfacial engineering and film-forming mechanism of perovskite films revealed by synchrotron-based GIXRD at SSRF for high-performance solar cells
摘要： Organic-inorganic hybrid perovskites as promising light-harvesting materials have been the focus of scientific research and development of photovoltaics recently. Especially, metal halide perovskites currently become one of the most competitive candidates for the fabrication of solar cells with record certified efficiency over 25%. Despite the high efficiency, many fundamental questions remain unclear and need to be addressed at both the material and device levels, such as weaker stability, poorer reproducibility, easier degradation influenced by water, oxygen, thermal factors, and so on. Based on recent reports, interfacial engineering plays a crucial role in controlling the behavior of the charge carriers and in growing high quality, defect-free perovskite crystals, therefore helping to enhance device performance and operational stability. However, little attention has been paid to the interface interaction mechanism among carrier transport layers and perovskite active layer. It is extremely urgent to explore the perovskite interfaces in details and to find out how its interface structure is relative to the efficiency and hysteresis in perovskites solar cells. Based on the Shanghai Synchrotron Radiation Facility (SSRF), we have established an advanced perovskite photovoltaic device preparation and in-line test system, developed a series of unique surface diffraction analysis methods based on ex situ and in situ grazing incidence X-ray diffraction (GIXRD), and reported a large number of novel synchrotron radiation results on crystallization of the perovskite photovoltaics films. Our main investigations are aimed to deeply in-situ study the perovskite film growth dynamics using synchrotron radiation GIXRD technology in combination with a customized mini online glove box (c(H2O,O2)<1 ppm) and temperature-humidity control equipment, and so on., which should provide solid theoretical background and point to the useful direction for designing and fabricating high-performance perovskites solar cells. Moreover, a multi-functional joint characterization technology that in-situ GIXRD simultaneously combines with conventional characterization methods at synchrotron radiation beamline station must be put on the agenda in future research, which greatly promotes much more comprehensive and intuitive understanding of the nucleation, microcrystallization, and degradation mechanisms of perovskite heterojunction films, and therefore further optimizing their chemical synthesis strategies at the molecular level for functional materials.
关键词： Growth dynamics,Perovskites solar cells,Device performance,Grazing incidence X-ray diffraction,In-situ study
更新于2025-09-23 15:19:57
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Electromagnetically induced grating in double quantum dot system
摘要： Electromagnetically induced grating (EIG) in the ladder-plus-Y double quantum dot system is modeled and the diffraction grating properties are explored in this structure. A high transmission function is obtained under the high pump field. This function is reduced under increasing the probe field due to the Kerr effect. The phase of this function depends on pumping. It is shown that the application of another two fields from the wetting layer (WL)-quantum dot (QD) type is more efficient in obtaining very high diffraction intensity. So, EIG with high diffraction intensity is obtained under a four-field application. Note that, WL-QD field effect is not studied earlier. Neglecting the WL effect reduces the transmission by five times. The diffraction intensity of this system is six times higher than that obtained from a single QD structure.
关键词： Quantum dot,Electromagnetically induced grating,Diffraction intensity
更新于2025-09-23 15:19:57
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Particle Size Distribution of Natural Clayey Soils: A Discussion on the Use of Laser Diffraction Analysis (LDA)
摘要： Particle size distribution is one of the most significant factors determining physical soil properties. Laser diffraction analysis (LDA) is an alternative method to the traditional hydrometric methods (HM) used to determine particle size distribution in soils. However, significant differences in fraction content are found in relation to the applied methods of a particle size test. Above all, measurements performed by LDA for clayey soils usually produce different results to those based on Stokes’ equation. Methodical problems, such as an appropriate method of dispersing the sample and the selection of LDA calculation theory, also play a significant role in fine soils. This paper contains the results of analyses of Neogene clays from Poland, which are characterized by differentiation with regard to the content of clay fraction particles. In this article, the validity of using laser diffraction analysis (LDA) for the identification and characterization of clayey sediments with common genesis is assessed. The possibility of finding reliable pedotransfer functions to the convert LDA results to a hydrometric analysis is discussed.
关键词： Stokes’ equation,clay soils,shape anisotropy,hydrometric method,particle size analysis,laser diffraction analysis (LDA)
更新于2025-09-23 15:19:57
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revealed by high-energy x-ray diffraction
摘要： We explore the evolution of the structural phase transition of (Sr, Ca)3Ir4Sn13, a model system to study the interplay between structural quantum criticality and superconductivity, by means of high-energy x-ray diffraction measurements at high pressures and low temperatures. Our results confirm a rapid suppression of the superlattice transition temperature T ? against pressure, which extrapolates to zero at a critical pressure of ≈1.79(4) GPa. The temperature evolution of the superlattice Bragg peak in Ca3Ir4Sn13 reveals a drastic decrease of the intensity and an increase of the linewidth when T → 0 K and p → pc. Such anomaly is likely associated with the emergence of quantum fluctuations that disrupt the formation of long-range superlattice modulation. The revisited temperature-pressure phase diagram of (Sr, Ca)3Ir4Sn13 thus highlights the intertwined nature of the distinct order parameters present in this system and demonstrates some similarities between this family and the unconventional superconductors.
关键词： high-energy x-ray diffraction,structural phase transition,superconductivity,quantum criticality,quantum fluctuations
更新于2025-09-23 15:19:57
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On the application of laser shock peening for retardation of surface fatigue cracks in laser beam-welded AA6056
摘要： The present study aims to investigate the extent to which the fatigue behaviour of laser beam-welded AA6056-T6 butt joints with an already existing crack can be improved through the application of laser shock peening. Ultrasonic testing was utilized for in situ (nondestructive) measurement of fatigue crack growth during the fatigue test. This procedure allowed the preparation of welded specimens with surface fatigue cracks with a depth of approximately 1.2 mm. The precracked specimens showed a 20% reduction in the fatigue limit compared with specimens without cracks in the as-welded condition. Through the application of laser shock peening on the surfaces of the precracked specimens, it was possible to recover the fatigue life to the level of the specimens tested in the as-welded condition. The results of this study show that laser shock peening is a very promising technique to recover the fatigue life of welded joints with surface cracks, which can be detected by nondestructive testing.
关键词： fatigue crack,aluminium alloys,laser beam welding,ultrasonic crack tip diffraction,residual stress,laser shock peening
更新于2025-09-23 15:19:57
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High resonance frequency in a coupled cavity DFB-LD with two phase-shifts
摘要： To realize a single-longitudinal-mode laser diode (LD) with high speed direct-modulation, a coupled cavity DFB-LD with two phase-shifts is proposed. From simulated results, it is expected that the resonance frequency of 71.3 GHz and the 3-dB down bandwidth of 95.9 GHz are obtained when the injected current is 3.075 times the threshold current. The resonance frequency for a main-mode is enhanced by an interaction between the main-mode and sub-mode. This interaction is called photon–photon resonance. The proposed coupled cavity DFB-LD is composed of two regions which are connected in series. Both regions have phase-shifted gratings. The phase-shift of the first region is ? π; the phase-shift of the second region is ? 0.9π. A phase-shift is not introduced at the interface of the two regions. The corrugation pitch of the second region is shorter than that of the first region by 1.6 nm; the grating coupling coefficient is 40 cm?1; each region length is 300 μm. These parameters are modest to fabricate DFB-LDs.
关键词： Longitudinal mode,Coupled cavity,Direct modulation,Semiconductor laser,Diffraction grating
更新于2025-09-23 15:19:57
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Analytical analysis of PT and quasi-PT symmetry in thick diffraction gratings using coupled-wave theory
摘要： The concept of parity-time (PT) symmetry in optics could potentially provide emerging solutions to exploit the benefits of optical gain in optical processing. With this regard, PT and quasi-PT symmetry were studied in thick optical diffraction gratings by derivation of explicit analytical expressions using the coupled-wave theory and verified by numerical calculations. The conditions to observe PT and quasi-PT symmetry were discussed in terms of the gain-loss ratio and the refractive index modulation amplitudes for both reflective and transmissive gratings. The results show that the criterion to attain quasi-PT symmetry for the reflective and transmissive gratings is in reverse in terms of the ratio of the modulation amplitude of the imaginary to that of the real part of the refractive index (|Γ|). According to the model, a grating with fringes parallel to the surface experiences broken PT symmetry for a wide range of gain-loss ratios. Furthermore, by varying the gain-loss ratio or |Γ|, some extrema could be observed in the normalized transmission power of the diffraction orders, while operating in the quasi-PT symmetry regime. The analytical solutions could predict and justify the positions of those extrema which could be advantageous to the design purposes.
关键词： diffraction,grating,quasi-PT symmetry,Parity-time symmetry
更新于2025-09-23 15:19:57