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Spatial-frequency domain imaging (SFDI) has been developed as an emerging modality for detecting early-stage bruises of fruits, like apples, due to its unique advantage of depth-resolved imaging feature, in comparison with the conventional imaging techniques under uniform or diffuse illumination. This paper presents theoretical and experimental analyses to determine the light penetration depth in apple tissues under spatially modulated illumination. First, light penetrating capacity of the demodulated direct component and amplitude component images was investigated to prove the performance of the constructed SFDI system. Simulation and practical experiments were then carried out to explore the maximum light penetration depths in ‘Golden Delicious’ apples, in terms of two critical parameters, i.e., image contrast, and ratio of peak-to-valley intensity. Finally, apple experiment for early-stage bruise detection using the estimated reduced scattering coefficient mapping was conducted to validate the results of light penetration depths. The results showed that the simulations produced comparable or a little larger light penetration depth in apple tissues (~ 2.2 mm) than the practical experiment (~ 1.8 mm, or ~ 2.3 mm). Apple peel further decreased the light penetration depth due to the high absorption properties of pigment contents. The apple bruise, located beneath the surface peel with the depth of about 0-1.2 mm, could be effectively detected by the SFDI technique. This study, to our knowledge, made the first effort to investigate the light penetration depth in apple tissues by SFDI, which would provide useful information for enhanced detection of early-stage apple bruising by selecting appropriate spatial frequency.

An analytical expression of a single Airyprime beam propagating in free space is derived. Upon propagation in free space, a single Airyprime beam in arbitrary transverse direction is the coherent superposition of the Airyprime and the Airy-related modes, which results in the interference enhancement effect under the appropriate condition. The Airy-related mode is the conventional propagating Airy mode with an additional π/2 phase shift and a weight coefficient of half the normalized propagation distance. Due to the peak light intensity in the initial plane being set to be 1, the strength of interference enhancement effect is characterized by the maximum light intensity. The maximum light intensity of a single Airyprime beam propagating in free space is independent of the scaling factor and is only decided by the exponential decay factor. When the exponential decay factor is above the saturated value, the interference enhancement effect disappears. When the exponential decay factor decreases from the saturated value, the maximum light intensity of a single propagating Airyprime beam increases, and the position of maximum light intensity is getting farther away. With the increase of the scaling factor, the position of maximum light intensity of a single propagating Airyprime beam is extended. The intensity distribution and the transverse Poynting vector of a single propagating Airyprime beam are demonstrated in different observation planes of free space. The flow direction of transverse energy flux effectively supports the interference enhancement effect of a single propagating Airyprime beam. The Airyprime beam is experimentally generated, and the interference enhancement effect is experimentally confirmed. The interference enhancement effect is conducive to the practical application of a single Airyprime beam.

In this paper, the lone generation of a new kind of beam named finite energy Airyprime (FEA) beam through the Airy transformation of the coherent superposition of four different elegant Hermite-Gaussian modes is reported for the first time. Analytical expressions of the centroid, the r.m.s beam width, the divergence angle, and the beam propagation factor of the FEA beam are derived in the output plane of Airy transformation, respectively. The effects of the Airy control parameters on the intensity distribution, the centroid, the r.m.s beam width, and the beam propagation factor are examined in detail through numerical examples. Unlike the Airy beam, the FEA beam upon free space propagation will be associated with an additional Airy mode, and the beam pattern of the FEA beams propagating in free space will evolve into a solid beam spot with two tails along two transverse directions, as well as the the intensity of main lobe of the FEA beam decays much slowly during free space propagation. Further, an experiment setup is established to generate the FEA beam via Airy transformation of four mixed elegant Hermite-Gaussian modes. The propagation characteristics such as the intensity distribution, the r.m.s beam width and the beam propagation factor are measured. The experimental results agree well with the theoretical predictions. Our study affords an effective and novel approach to generate the FEA beam, and is beneficial to expand the potential application of the FEA beam.

Researchers are puzzled whether the enhancement of the abruptly autofocusing ability caused by a linear chirp factor is accompanied by the shortening or the extension of the focal length. In this Letter, a circular Airyprime beam is chosen as the research object to reveal this mystery. Extension or shortening of the focal length in the enhancement of the abruptly autofocusing ability depends on the exponential decay factor a and the dimensionless radius of the primary ring. When a is small enough, there exists a critical value for the dimensionless radius. If the dimensionless radius is greater than the critical value, the focal length is shortened in the enhancement of the abruptly autofocusing ability. If the dimensionless radius is less than the critical value, the focal length is extended in the enhancement of the abruptly autofocusing ability. As a increases, the critical value for the dimensionless radius decreases until it reaches zero. The physical mechanism of extension or shortening of the focal length in the enhancement of the abruptly autofocusing ability is elucidated.

The first-order and the second-order chirped factors are imposed on the Airyprime beam, and the analytical expression of the chirped Airyprime beam propagating in free space is derived. The phenomenon that the peak light intensity on observation plane other than initial plane is greater than that on initial plane is defined as the interference enhancement effect, which is caused by the coherent superposition of the chirped Airyprime and the chirped Airy-related modes. The effects of the first-order and the second-order chirped factors on the interference enhancement effect are theoretically investigated, respectively. The first-order chirped factor only affects the transverse coordinates where the maximum light intensity appears. The strength of interference enhancement effect of the chirped Airyprime beam with any negative second-order chirped factor must be stronger than that of the conventional Airyprime beam. However, the improvement of the strength of interference enhancement effect caused by the negative second-order chirped factor is realized at the expense of shortening the position where the maximum light intensity appears and the range of interference enhancement effect. The chirped Airyprime beam is also experimentally generated, and the effects of the first-order and the second-order chirped factors on the interference enhancement effect are experimentally confirmed. This study provides a scheme to improve the strength of interference enhancement effect by controlling the second-order chirped factor. Compared with traditional intensity enhancement methods such as using lens focusing, our scheme is flexible and easy to implement. This research is beneficial to the practical applications such as spatial optical communication and laser processing.

The present study investigating the experimental equilibrium solubility of 2-chloro-4-amino-6,7-dimethoxyquinazoline (CADQ) dissolved in 12 kinds of neat organic solvents, including methanol, ethan...

The solid–liquid phase equilibrium of ticagrelor in methanol, ethanol, n-propanol, isopropanol, 1-butanol, isobutanol, n-octanol, acetonitrile, ethyl acetate, toluene, 2-butanone, and cyclohexanone...

Zonisamide is moderately soluble in water with a reported solubility of 0.8 mg·mol–1 (6.78 × 10–5 in mole fraction). The objective is to study the solubility of zonisamide in methanol, ethanol, n-p...

Intermetallic compounds are atomically ordered inorganic materials containing two or more transition metals and main-group elements in unique crystal structures. Intermetallics based on group 10 an...

The experimental gramine solubilities in pure organic monosolvents containing methanol, ethanol, n-propanol, isopropanol, n-butanol, acetone, toluene, acetonitrile, ethyl acetate, 1,4-dioxane, n-oc...

In this paper, we introduce a novel kind of abrupt autofocusing beams namely the generalized circular Airy derivative beams (CADBs) as an extension of circular Airy beam (CAB). The propagation dynamics of the CADBs is examined theoretically. Our results show that the CADBs exhibit stronger autofocusing ability than the CAB under the same condition. The physical mechanism of the abruptly autofocusing of the CADBs is interpreted by mimicking the Fresnel zone plate lens. Here, the abruptly autofocusing ability is described by a ratio K = Ifm/I0m where Ifm and I0m correspond to the maximum intensities in the focal and the source planes, respectively. As an example, the K-value of the circular Airyprime beam (CAPB, the first-order Airy derivative beam) is about 7 times of that of the CAB. In addition, the CAPB have narrower FWHM (full width at half maxima) in the focus position than the CAB, and the focal spot size of the CAPB is smaller than that of the CAB. Furthermore, we establish an optical system involving a phase-only spatial light modulator to generate the CAPB and measure its autofocusing characteristics experimentally. The measured K-value is about 9.4 percentage error between theory and experiment owing to the imperfection generation of the CAPB. The proposed generalized CADBs will find applications in biomedical treatment, optical manipulation and so on.

It is of great significance to solve the problem that improving autofocusing ability is always at the cost of shortening focal length. By introducing a linear chirp into a ring Airyprime beam array, an optimization scheme to simultaneously achieve the enhancement of autofocusing ability and the extension of focal length is proposed. The autofocusing ability can be enhanced by up to 72.28%, and the corresponding focal length is extended by 34.81%. The focal length can be extended by 110.28% at most, and the corresponding autofocusing ability is improved by 48.59%. To verify the feasibility of this scheme, we have carried out an experiment for the generation of a ring Airyprime beam array with a linear chirp, and the experimental results for autofocusing ability and focal length are in good agreement with theoretical results. Our findings have potential applications in many aspects, such as free space optical communication.

Recently, a new type of abruptly autofocusing beam called circular Airyprime beam (CAPB) has been reported. Its abrupt autofocusing ability has been proven to be approximately seven times that of a circular Airy beam under the same conditions. Further improving the abrupt autofocusing ability of the CAPB without changing the beam parameters is a concern in optical research. In this study, we investigated the effect of introducing first- and second-order chirped factors on the abrupt autofocusing ability of the CAPB. When the positive first-order chirped factor was below the saturated chirped value, the abrupt autofocusing ability of the chirped CAPB was stronger and the focus position was smaller compared with those of the conventional CAPB. Regarding the abrupt autofocusing ability, there was an optimal value for the first-order chirped factor. At the optimal value, the abrupt autofocusing ability of the chirped CAPB was the strongest. On the other hand, a positive second-order chirped factor promoted the abrupt autofocusing ability of the CAPB and shortened the focus position. The introduction of such value was more effective than the introduction of a positive first-order chirped factor in promoting abrupt autofocusing of the CAPB. The abrupt autofocusing ability of the CAPB was further improved by combining the optimal first-order chirped factor and a positive second-order chirped factor. Finally, the chirped CAPB was experimentally generated, and the corresponding abrupt autofocusing behaviors were measured, validating the theoretical results. Overall, we provide an approach for improving abruptly autofocusing CAPBs.

A ring Airyprime beams (RAPB) array, which consists of N evenly displaced Airyprime beamlets in the initial plane, is first introduced, to the best of our knowledge, in this Letter. Here, we focus on the effect of the number of beamlets N on the autofocusing ability of the RAPB array. With the given beam parameters, an optimal number of beamlets, which is the minimum number of beamlets to realize the saturated autofocusing ability, is selected. The focal spot size of the RAPB array remains unchanged before the number of beamlets reaches the optimal number of beamlets. More importantly, the saturated autofocusing ability of the RAPB array is stronger than that of the corresponding circular Airyprime beam. The physical mechanism of the saturated autofocusing ability of the RAPB array is interpreted by simulating the Fresnel zone plate lens. The influence of the number of beamlets on the autofocusing ability of the ring Airy beams (RAB) array under the same beam parameters with the RAPB array is also presented for comparison. Our findings are beneficial for the design and application of the ring beams array.

The solubility profiles of sancycline in methanol, ethanol, n-propanol, isopropanol, 1-butanol, isobutyl alcohol, n-octanol, cyclohexane, n-hexane, acetonitrile, ethyl acetate, and 1,4-dioxane were...

The solubility values of 5-chloro-8-hydroxyquinoline and 5,7-dichloro-8-hydroxyquinoline in six pure solvents at temperatures ranging from 283.15 to 323.15 K was determined by the isothermal satura...

The solubility of 5-methyl-2-pyrazinecarboxylic acid (MPCA) in 12 pure solvents within the temperature range from 273.15 to 313.15 K under 101.3 kPa was determined and correlated by some thermodyna...

Analytical optical field of a cosh-Airy beam propagating in uniaxial crystals orthogonal to the optical axis is presented. Analytical expressions of the centre of gravity, the beam spot size, and the linear momentum for the cosh-Airy beam in uniaxial crystals are also derived, respectively. The propagation properties of a cosh-Airy beam are numerically demonstrated in the uniaxial crystal. The cosh-Airy beam still has the feature of self-acceleration in the two transverse directions. However, the cosh-Airy beam in the y-direction accelerates more slowly than that in the x-direction. The centre of gravity and the beam spot size in the y-direction are always less than those in the x-direction. The influence of the uniaxial crystal on the intensity distribution, the phase distribution, the centre of gravity, the beam spot size, and the linear momentum of a cosh-Airy beam is investigated. The effect of the cosh part on the centre of gravity, the beam spot size, and the linear momentum is also studied in detail. The centre of gravity of the cosh-Airy beam is less than that of the corresponding Airy beam. However, the beam spot size and the linear momentum of the cosh-Airy beam are larger than those of the corresponding Airy beam.

The solubility data of 5-nitrosalicylaldehyde in methanol, ethanol, n-propanol, isopropanol, 1-butanol, acetonitrile, acetone, cyclohexanone, ethyl acetate, 1,4-dioxane, toluene, and water were det...

The dissolving capacity of lenalidomide in pure and mixed solvents is limited. The purpose of this work is to enhance the solubility and study the solubility parameter of pure and mixtures (δ1) to characterize different types of solubility profiles. The solubility of lenalidomide in acetonitrile (MeCN), methanol (MT), ethanol (EA), ethyl acetate (EAC) and isopropanol (IPA) was experimentally determined at T = 293.15–333.15 K. Its solubility in binary mixtures of EA and EAC was also investigated. The polarity of lenalidomide is related to the tendency of the solubility data against the solubility parameter δ1 of pure and binary solvent mixtures. Consequently, the method of linear solvation energy relationships introduced by Kamlet, Abboud and Taft (KAT-LSER) was applied to analyze the effect of the solute-solvent intermolecular interactions on the solubility in pure solvents. In order to estimate maximum solubility in a specific co-solvent ratio, we also attempt to calculate the Hansen solubility parameter (HSP) of lenalidomide and to compare it with HSP of solvent mixture. Based on the experimental solubility data, two thermodynamic models including modified Apelblat equation and Jouyban-Acree model were then assessed. Meanwhile, a modification of the extended Hildebrand solubility approach (EHSA) including the Hildebrand solubility parameter (δ1) and the acidic and basic partial solubility parameters (δ1a and δ1b) of the solvent mixtures was used to simulate lenalidomide solubility in pure and binary mixture compositions.

The purpose of this work is to study the dissolution behavior of lapatinib ditosylate (LB-DT) in different solvents and determine the suitable solvent and composition to improve dissolving capacity. In selected pure organic solvents, LB-DT exists in the form of anhydrous. The largest solubility data was found in acetone and lowest in toluene at the determined temperature, and it decreases as the following order: acetone > tetrahydrofuran (THF) > acetonitrile > n-propanol > isopropanol > 1-butanol > ethyl acetate > toluene. While in mixture of THF aqueous, it exist the form of monohydrate, and the solubility increases at first and then decreases with the increasing mass fraction of THF. The composition dependence of the solubility has a maximum around w = 0.6 at all investigated temperatures. The (KAT-LSER) model was applied to analyze the effect of the solute-solvent intermolecular interactions on the solubility in pure organic solvents. A series of models based on solubility parameter and the solid-liquid equilibrium equation were employed to provide insight to data. In the following, the analysis of apparent thermodynamic properties indicates that the dissolution process is apparently not only endothermic but also entropy-driving.

The equilibrium solubility of 1,5-naphthalenediamine and 1,8-naphthalenediamine in six pure solvents over a temperature range from 273.15 to 313.15 K was determined. Within the investigated tempera...

Carbon nanotubes (CNTs) have been regarded as one of the most hopeful candidates for transporting drugs to target cells because of their huge surface area, hollow structure, and enhanced cellular u...

The basis of purification and further theoretical studies of iohexol is the solubility in different solvents. The solubility of iohexol in 12 monosolvents (ethanol, n-propanol, isopropanol, n-butan...

This work was to construct isothermal binary and ternary solid–liquid phase diagrams based on the measured mutual solubility data of mixtures of 2-nitro-p-phenylenediamine + ethyl acetate + isoprop...

A green and biodegradable carbohydrate-derived alkylamine was designed and employed as ligand for Ullmann type C–N coupling catalyzed by copper in water. The coupling of aryl iodide and N-nucleophiles were examined and moderate to excellent yields were obtained. In addition, the in-water coupling strategy was expanded successfully to the reaction of indoles with 4-iodoanisole. By measuring the solubility, it is speculated that carbohydrate-derived alkylamine plays the role of chelating copper and promoting the dissolution of 4-iodoanisole in water. Remarkably, this methodology was environmentally friendly and economical because of the use of aqueous media in place of organic solvents.