Mutual Intensity Research Articles

Phase retrieval in propagation-based X-ray imaging beyond the limits of transport of intensity and contrast transfer function approaches.

We derive a phase retrieval formula for propagation-based phase contrast X-ray imaging that does not require weakly attenuating objects or short propagation distances. It is directly applicable to both single- and multiple-distance scenarios. We show the validity conditions and study the error of the underlying mutual intensity approximation, which uses the common assumptions of weak phase shift variations and phase-attenuation duality. The approximation generalizes those behind the transport of intensity (TIE) and contrast transfer function (CTF) models, and it approaches them when their respective additional assumptions are satisfied. When they are not, it clearly outperforms them, which we show both theoretically and practically on synthetic and measured data.

Random phase plate designed by the genetic algorithm for decoherence in energy homogenization units of a photolithography illumination system

The microlens array (MLA) is used in the flexible pupil shaping module of lithography illumination system for energy balance. However, the coherence of the light source can lead to interference patterns. Most of the decoherence methods are restricted for the pulse laser and the scanning exposure application. To solve this issue, a specific random phase plate (RPP) is designed to eliminate the interference patterns caused by the coherence of the light source. The model of partially coherent light propagation in the MLAs homogeneous system is established based on the mutual intensity theory, and the genetic algorithm is introduced to design a high-performance RPP. The corresponding measurement device is constructed, and the intensity of the image plane light field is measured. Experiment results indicate that the intensity integral non-uniformity is 32.14% in the x-direction and 66.04% in the y-direction without the RPP, and the intensity integral non-uniformity is 22.95% in the x-direction and 19.18% in the y-direction with the RPP, which verifies the feasibility of the proposed method.

Political investing of mutual funds

We study whether and how political investing influences the performance of mutual funds. We provide robust evidence of the positive relation between mutual funds' political connection intensity exposure and future performance. The gross return gap between the top and bottom quintiles of mutual funds ranked by exposure to political connection intensity reaches 4.38% on an annualized basis. The performance gap is larger and more significant for mutual funds with high characteristic-selectivity skills. Our findings show that political connection intensity exposure is more closely related to stock selection skill than to political investing risk premium, political investing timing ability or corruption.

Gas concentration monitoring based on the two-dimensional reflection intensity curve of Bloch surface wave

Proposed is a gas concentration monitoring method that is based on the dispersion of Bloch surface wave. Different from the conventional sensing method using a single parameter such as wavelength or angle, all measured data was fully analyzed from a two-dimensional reflection intensity curve of a Bloch surface wave by mutual reflection intensity, which can reflect changes in either the refractive index or the airflow motion. This method does not require recording specific wavelength or incidence angles and measurement of small wavelengths or angle deviations. Our airflow monitoring device has a detection limit of 1.14 × 10−4RIU and good linearity in an open environment with high noise levels. However, in a closed environment, we achieved stable monitoring of the dry ice sublimation process and prediction.

Mutual optical intensity propagation through non-ideal two-dimensional mirrors.

The mutual optical intensity (MOI) model is a partially coherent radiation propagation tool that can sequentially simulate beamline optics and provide beam intensity, local degree of coherence and phase distribution at any location along a beamline. This paper extends the MOI model to non-ideal two-dimensional (2D) optical systems, such as ellipsoidal and toroidal mirrors with 2D figure errors. Simulation results show that one can tune the trade-off between calculation efficiency and accuracy by varying the number of wavefront elements. The focal spot size of an ellipsoidal mirror calculated with 100 × 100 elements gives less than 0.4% deviation from that with 250 × 250 elements, and the computation speed is nearly two orders of magnitude faster. Effects of figure errors on 2D focusing are also demonstrated for a non-ideal ellipsoidal mirror and by comparing the toroidal and ellipsoidal mirrors. Finally, the MOI model is benchmarked against the multi-electron Synchrotron Radiation Workshop (SRW) code showing the model's high accuracy.

Propagation of the Hermite-Laguerre-Gaussian Schell-Model Beams Through Mode Converter

Mode converter is an astigmatic optical system that allows transforming the set of coherent Hermite-Gaussian modes with dislocation singularities into Laguerre-Gaussian one, which carries the OAM, and vice versa. The intermediate Hermite-Laguerre-Gaussian (HLG) modes are also obtained for a certain values of mode converter parameter. All these mode sets are used or can be used for information encoding in free space optical communication. Such mode transformation is well understood in the coherent case, however, the propagation of partially coherent HLG modes through the mode converter has not been addressed yet. Here, we derive a comprehensive closed-form expression for the evolution of the mutual intensity of HLG Schell-model beams (HLG-SMBs) during propagation through the mode converter. It is compared with the expression for HLG-SMBs propagation through rotationally symmetric system. We conclude that the mode converter also works for the partially coherent case, but only for intensity distribution. While the mutual intensity and, in particular, cross-correlation function are different in the output of the considered optical systems. This theoretical analysis is important for applications of the HLG sets in optical communication when the mode decoherence has to be taken into account.

Partially coherent light propagation through a kinoform lens.

Combining wave optics propagation and geometric ray tracing, the mutual optical intensity (MOI) model is extended to quantitatively simulate the propagation of partially coherent light through a kinoform lens at high speed. The MOI model can provide both a high accuracy and a high efficiency simulation. The intensity and coherence degree distributions at the focal plane are calculated using the MOI model. It is beneficial to improve the focusing capability of the kinoform lens by reducing the coherence or increasing the number of lens steps. In addition, increasing the number of steps is also beneficial to increase the photon flux and reduce the depth of focus.

Simultaneous Conductivity and Permeability Reconstructions for Electromagnetic Tomography Using Deep Learning

Electromagnetic tomography (EMT) is a research hotspot in electrical tomography, which has wide application prospect for multiphase flow measurement. The existing EMT usually visualizes the distributions of conductivity or permeability separately. In order to realize the simultaneous imaging of different electromagnetic characteristics in the measurement area and improve the quality of the reconstructed images, a deep learning based multi-parameter EMT method is proposed in this paper. Firstly, the information from the mutual inductance and magnetic induction intensity of the imaging area is measured respectively. Then, the Landweber algorithm is used to reconstruct the initial conductivity and permeability images using above measurements. Finally, the initial images are input into the improved DeepLabv3 network for image segmentation and the images of conductivity and permeability distributions with clear boundary and accurate size and position are output. The images reconstructed by the improved DeepLabv3 network are compared with those from traditional methods, UNet++, LinkNet and PAN networks through the simulation and experiment. The experimental results show that our method achieves RMSE of 0.1667, CC of 0.6984 and SSIM of 0.6542 on average for permeability distribution reconstruction, and RMSE of 0.1907, CC of 0.7791 and SSIM of 0.7538 on average for conductivity distribution reconstruction. These results prove that the proposed method can simultaneously obtain the conductivity and permeability distributions with high-quality reconstructed images. Our code is publicly available at https://github.com/Tougerr/Landweber-DLv3.

Research on the Control of Mining Instability and Disaster in Crisscross Roadways

In order to solve the disaster caused by the instability of spatial crisscross roadways under the action of leading abutment pressure in the coal mine face, combined with a specific engineering example, the methods of theoretical analysis, numerical simulation and field measurement are adopted to simulate and analyze the stress mutual disturbance intensity and influence range of spatial crisscross roadways. The evolution law of the plastic zone in spatial crisscross roadways under the influence of mining is explored, and the key to mining instability control is made clear. The roof of the return air roadway, the shoulder angle of the two sides and the coal wall are the key parts of surrounding rock stability control. On this basis, the cooperative control scheme of changing the roadway section shape (straight wall semicircular arch), supporting (anchor cable and “U” section steel) and modifying (grouting) is put forward. Through the field measurement, within the influence range of the return air roadway, the displacement deformation of the top and bottom is less than 200 mm, which achieves the goal of roadway safety and stability. Furthermore, based on the theory of “butterfly plastic zone”, the mechanical mechanism of the overall instability of the spatial crisscross roadway is revealed; that is, during the advance of the working face, the advance mining stress is superimposed with the surrounding rock stress of the crisscross roadway, and the peak value of the partial stress of the surrounding rock mass of the crisscross roadway is increased. The expansion of the plastic zone is intensified, and beyond 7 m from the crisscross position, the shoulder angle of the two sides and the leading plastic zone of the coal wall of the working face are connected with each other, which leads to the overall failure and instability of the surrounding rock between the roadways at the intersection.

Altruistic mode selection and coordination in a low-carbon closed-loop supply chain under the government's compound subsidy: A differential game analysis

Under low-carbon circular economy, how the government and low-carbon closed-loop supply chain (LC-CLSC) members make decisions to achieve carbon neutrality and recycling of waste resources becomes a prominent part of the study. This paper studies the altruistic mode selection and coordination of the LC-CLSC under the compound subsidy of the government from a long-term dynamic perspective. The results show that the altruistic behavior of the manufacturer as the leading party can promote emission reduction and recycling activities, and increase the retailer's profit and total profit while avoiding damage to its profit when its altruistic intensity is maintained at a reasonable level. The altruistic behavior of the retailer as the subordinate party will inhibit emission reduction and recycling activities, and increase the manufacturer's profit by damaging its profit, therefore leading to a decline in the total profit. The emission reduction subsidy rate decreases as the mutual altruistic intensity increases. The recycling subsidy rate decreases as the manufacturer's altruistic intensity increases, but it will increase as the retailer's altruistic intensity increases. Compared with other altruistic modes, the leading party manufacturer's unilateral altruistic mode can achieve a higher level of emission reduction, recycling rate, total profit, consumer surplus and social welfare.

Enhanced activity of AZD5582 and SM-164 in rabies virus glycoprotein-lactoferrin-liposomes to downregulate inhibitors of apoptosis proteins in glioblastoma

Upregulated proliferation of neoplastic cells from suppressing apoptotic signals associated with the inhibitors of apoptosis proteins (IAP) makes difficult the achievement of therapeutic efficiency against glioblastoma multiforme. Studies in the last few years have witnessed a paradigm focusing on targeting IAP using its antagonists, such as Smac mimetics, to restrain tumor malignancy. A Smac mimetic compound needs to penetrate the blood-brain barrier (BBB), and must be internalized into cerebral tumor for improved chemotherapy. Rabies virus glycoprotein (RVG) and lactoferrin (Lf)-grafted liposomes were developed in this study to carry two IAP antagonists, AZD5582 and SM-164, across the BBB and to induce apoptosis in U87 MG and human brain cancer stem cells (HBCSCs). Liposomes modified with RVG slightly reduced BBB tightness and enhanced capability of AZD5582 and SM-164 for traversing the barrier because of their brain-targeting ability. Immunofluorescence and western-blot results revealed that AZD5582- and SM-164-encapsulated liposomes facilitated mutual curative intensity, effectively triggered apoptosis of U87 MG and HBCSCs, reduced the expression of cellular IAP 1 (cIAP1) and X-linked IAP (XIAP), and enhanced the expression of caspase-3. Hence, RGV-Lf-liposomes carrying AZD5582 and SM-164 can be promising formulations to activate apoptosis of U87 MG and HBCSCs, and this functionalized drug delivery system targeting cIAP and XIAP is a potential strategy to cure glioblastoma in clinical cancer management.

Research on partially coherent light propagation through zone plates

The MOI (mutual optical intensity) model is further developed and extended to analyze the mutual optical intensity propagation through a zone plate. This is the first study to quantitatively analyze the influence of the partial coherence property on the spatial resolution of zone plates. Increasing the source coherence length is beneficial for improving the spatial resolution of the zone plate; however, apparent diffraction peaks are observed at the focal plane. Reducing the sizes of the central stop and the order selecting aperture (OSA) can improve the signal-to-noise (SNR) ratio at the cost of the photon flux. Furthermore, we analyze the coherence property propagation through the STXM beamline at Shanghai Synchrotron Radiation Facility (SSRF), where a zone plate is used to focus the light into ∼30 nm. The coherence property increases and the photon flux decreases with decreasing exit slit size, which is beneficial for improving the spatial resolution of the zone plate. Therefore, the spatial resolution and flux can be balanced by optimizing the exit slit size.

Species patch size at seeding affects the productivity of mixed legume-grass communities

The impact of inter- and intraspecific neighboring plants on mixed legume-grass communities has rarely been explored in relation to seeded species patch size. In this study, two native perennial species, the legume alfalfa (Medicago sativa L.) and the grass tall fescue (Festuca arundinacea L.), were investigated as monocultures and in mixture. A three-year growth experiment was conducted to investigate the effects of plant-plant competitive interactions on fine-scale seeding patterns: monoculture, three different conspecific patch sizes (1.0, 0.5, and 0.25 m side length of squares) and a control in which the seeds were mixed and scattered (i.e., patches were not formed) as in conventional seeding. The results demonstrated significant differences in the mutual effect intensity in all conspecific patch sizes, indicating the presence of grass-legume interactions on mixed plant communities. Smaller patch sizes resulted in better facilitation by higher neighbor effect intensity when compared with a larger patch size and the conventional mixture. Seedings in the smallest patch size of 0.25 m × 0.25 m showed intra- and interspecific competition and significantly improved aboveground productivity compared with the other patch sizes. We directly quantified the variation of species neighbor effect intensity between grass and legume mixtures among different species patch sizes at seeding. Integrating this knowledge into species interaction models in plant community ecology could greatly enhance our understanding of species coexistence in grasslands as well as provide opportunities for manipulating competition to achieve specific agronomic aims.

Analysis of partially coherent light propagation through the soft X-ray interference lithography beamline at SSRF.

The mutual optical intensity (MOI) model is extended to the simulation of the interference pattern produced by extreme ultraviolet lithography with partially coherent light. The partially coherent X-ray propagation through the BL08U1B beamline at Shanghai Synchrotron Radiation Facility is analysed using the MOI model and SRW (Synchrotron Radiation Workshop) method. The fringe intensity at the exposure area is not uniform but has similar envelope lines to Fresnel diffraction, which is explained by the diffraction from the finite grating modelled as a single aperture. By balancing the slit size and photon stop size, the fringe visibility, photon flux and intensity slope can be optimized. Further analysis shows that the effect of pink light on the aerial images is negligible, whereas the third-harmonic light should be considered to obtain a balance between high fringe visibility and high flux. Two grating interference exposure experiments were performed in the BL08U1B beamline. The aerial image depth showed that the polymethyl methacrylate photoresist depth was determined by the X-ray coherence properties.

Near-field spatial coherence of structured incoherent optical sources

Spatial coherence is a fundamental property of light with many applications. However, if a light source is spatially incoherent and structured, its near-field coherence is difficult to evaluate directly because of the complexity of the emitted random light. In this work, we propose a general approach to calculate the near-field mutual intensity and transverse coherence length of propagating radiation from a periodically structured incoherent source using optical reciprocity. If the structure period is subwavelength and much smaller than the source, the mutual intensity reduces to a Fourier transform of the angular intensity spectrum of the radiation. Tailoring the near-field spatial coherence of incoherent sources by structuring can be used, e.g., for applications in optical sensing and imaging.

System Transfer Function of Incoherent Light Illumination System

Generally, most imaging cases are incoherent light field illumination, and incoherent light illumination system has the advantages of simple installation and no coherent noise, therefore it has received extensive attention. The optical transfer function of illumination system is an effective method to evaluate the imaging quality of such optical system. In order to evaluate the imaging quality of an optical system, the specific form of the system transfer function should be known. However, due to the in-coherent nature of the optical field, both the input function and the impulse response can only be non-negative real functions, it is difficult to deal with lots of bipolar inputs and impulse responses. In this paper, two methods for calculating the system transfer function of incoherent light illumination system under quasi-monochromatic light illumination are given. Method 1: the coherence of incoherent light is defined, and the coherent system transfer function based on the characteristics of the system transfer itself is deduced. Method 2: based on the theory of partially coherent light, started from Kirchoff’s diffraction integral, the quasi-wavefront aberration is introduced, and the spatial coherence of the light field is described by the mutual intensity instead of the mutual coherent function, finally the system transfer function of incoherent illumination is derived. The calculation formula is simple and the transfer function of incoherent light system can be calculated accurately and easily. The work in this paper is helpful to the study of the new phenomena related to incoherent optical imaging.

Phase analysis for partially coherent light propagating through an optimized aperture in a synchrotron beamline.

The mutual optical intensity propagation of partially coherent light through a beamline is calculated for different aperture sizes and positions. The coherence, intensity and phase distribution can be extracted from the mutual optical intensity. The phase distribution depends on the aperture size and position. The results show that the widest flat phase distribution is obtained at the optimized aperture size and position. The aperture plays a more important role for partially coherent light than for incoherent light. The influence of the aperture size and position on the intensity and spot size at the focal plane is also analyzed. A way to obtain a balance between the flat phase distribution area, spot size and intensity for partially coherent light in the beamline is demonstrated.

Interferometric transmission probing with coded mutual intensity

We introduce a new interferometric imaging methodology that we term interferometry with coded mutual intensity, which allows selectively imaging photon paths based on attributes such as their length and endpoints. At the core of our methodology is a new technical result that shows that manipulating the spatial coherence properties of the light source used in an interferometric system is equivalent, through a Fourier transform, to implementing light path probing patterns. These patterns can be applied to either the coherent transmission matrix, or the incoherent light transport matrix describing the propagation of light in a scene. We test our theory by building a prototype inspired by the Michelson interferometer, extended to allow for programmable phase and amplitude modulation of the illumination injected in the interferometer. We use our prototype to perform experiments such as visualizing complex fields, capturing direct and global transport components, acquiring light transport matrices, and performing anisotropic descattering, both in steady-state imaging and, by combining our technique with optical coherence tomography, in transient imaging.

PROSPECTS FOR INTEGRATION

This research allows us to consider the problem of transition to monetary integration between the countries participating in the EAEU from the importance standpoint of economic prerequisites. The practical significance of the work lies in the substantiation of the objective prerequisites for the formation and creation of a monetary union in the course of regional integration processes development. The statistical data on foreign investments in the EAEU countries, on the share of gross volumes of mutual trade in the total volume of foreign trade in the EAEU as a whole and in the EAEU member states, are given. Analysis of mutual trade and investment indicators showed an insufficient level of economic convergence in the EAEU, assessed from the standpoint of the mutual trade intensity and mutual foreign direct investment intensity. At the moment, the volumes and dynamics of trade and investment flow between the EAEU member states do not cause an objective need for a transition to monetary cooperation at the level of a currency union.

FOUNDATIONS OF REGIONAL MONETARY INTEGRATION

The statistical data on foreign investments in the EAEU countries, on the share of gross volumes ofmutual trade in the total volume of foreign trade in the EAEU as a whole and in the EAEU member states, are given.Analysis of mutual trade and investment indicators showed an insufficient level of economic convergence in theEAEU, assessed from the standpoint of the mutual trade intensity and mutual foreign direct investment intensity. Atthe moment, the volumes and dynamics of trade and investment flow between the EAEU member states do not causean objective need for a transition to monetary cooperation at the level of a currency union. This research allows us toconsider the problem of transition to monetary integration between the countries participating in the EAEU from theimportance standpoint of economic prerequisites. The practical significance of the work lies in the substantiation ofthe objective prerequisites for the formation and creation of a monetary union in the course of regional integrationprocesses development.