Crystal Research and Technology最新文献

This study investigates the influences of the evaporation temperature and Mg²⁺ concentration on the crystallization of an ammonium sulfate mother liquor. Specifically, their effects on the solubility, metastable zone width, crystallization amount, average particle size, and coefficient of variation of ammonium sulfate are examined through the laser and evaporation crystallization methods. Results show that solubility increases and the metastable zone width narrows with an increase in the evaporation temperature. At an evaporation temperature of 338.15 K, the controllability of the crystallization process improves and explosive nucleation does not easily occur. In this case, crystals with large average particle sizes, regular morphologies, and high crystallinity are obtained. With an increase in the Mg²⁺ concentration in the solvent, solubility decreases. The added Mg²⁺ covers the active nucleation sites, thus hindering the nucleation of ammonium sulfate and widening the metastable zone width. At a Mg²⁺ concentration of 0.9 g L⁻¹ or higher, Mg²⁺ covers the active surfaces of the grains. This inhibits normal crystal growth and hinders the nucleation and growth of ammonium sulfate crystals, so the crystallization amount of ammonium sulfate significantly reduces.

The wet dissolution process of lime is an effective approach for synthesizing calcium hydroxide. Process parameters and additives exert influence on the product particle. Among the process parameters, lime particle size, reaction temperature, and time have a significant impact on product particle size, followed by liquid-solid ratio and stirring speed. The experiment proved that reaction time affects product particle size by affecting the crystal growth, while other process parameters affect the particle size by affecting the ion diffusion behavior. In terms of inorganic additives, Ca(OH)₂ has minimal effect on product particle size; however, NaOH and CaCl₂ can significantly enhance it with a greater dose leading to a larger increase. The experiment proved that Ca(OH)₂, NaOH, and CaCl₂ influence particle size through their impact on ion diffusion behavior. Regarding organic additives, soluble starch exhibits the greatest effect on product size followed by triethanolamine and polyvinylpyrrolidone K30. The experiment proved that soluble starch, triethanolamine, and polyvinylpyrrolidone K30 affect product particle size by influencing its crystallization position. Finally, an ultrafine slurry of calcium hydroxide was prepared using the lime wet digestion method based on the aforementioned research, with particle size distribution characterized by D10, D50, and D90 values of 0.303, 1.750, and 4.534 µm respectively.

Cover image provided courtesy of Jianguang Zhou, Research Center for Analytical Instrumentation, Institute of Cyber-Systems and Control, State Key Laboratory of Industrial Control Technology, Zhejiang University, China.

Implementing combination medication through crystal engineering technology receives increasing attention from researchers due to improvements in the clinical treatment effects as well as the physicochemical properties of the drug. Berberine (BER) is commonly used to treat gastroenteritis and bacterial diarrhea, with the problems of poor solubility and low oral bioavailability. Recently, it is found that gallic acid (GA) also has anti-inflammatory and anti-bacterial activities. Therefore, if the above-mentioned two ingredients can be combined, it is possible to enhance the therapeutic effects and physicochemical properties of BER. Inspired by this, 8-hydroxy-7,8-dihydroberberine (8H-HBER) in this study is employed to react with gallic acid to yield BER gallate dihydrate (2BER-2GA-2 W). Furthermore, dissolution experiments demonstrate that the maximum apparent solubility (MAS) of 2BER-2GA-2 W in dilute hydrochloric acid solution medium (pH 1.2) has increased by 7 times compared to the commercial form of BER, because of avoiding the common-ion effect. Moreover, 2BER-2GA-2 W has also obviously enhanced stability relative to the commercial form of BER. In addition, 2BER-2GA-2 W has a better inhibitory effect on Staphylococcus aureus (S. aureus) relative to the commercial form of BER. Hence, 2BER-2GA-2 W will be a promising solid-state form of BER for its further development.

The present investigation reports the variations of the microstructure and electrical properties due to a change in the ZnSb₂O₆ content of ZnO varistors. The impact of the ZnSb₂O₆ additive on both microstructure and electrical properties in ZnO varistors is studied via the X-ray diffraction (XRD) and an impedance analyzer. Zn₇Sb₂O₁₂ spinel phase and single hexagonal ZnO phase are detected in ZnO varistors with the addition of ZnSb₂O₆. The ZnO varistors with 5 mol% ZnSb₂O₆ have the highest nonlinear coefficient (43.2) and the lowest leakage current density (3.96 A cm⁻²). The resistivity of grain boundary ρ_gb increases continuously with the increasing content of ZnSb₂O₆ as demonstrated by impedance measurements. Additionally, low values of dielectric loss at high frequencies suggest a ZnO varistor doped with ZnSb₂O₆ is suitable for high frequency device applications.

This paper discusses the optimization of the growth temperature and Sb/In ratio of 1 µm InSb thin films grown on GaAs substrates by molecular beam epitaxy due to the InSb materials with larger lattice constants have smaller growth windows. The results show that atomic steps can be clearly seen in InSb thin films grown at 420 °C with a Sb/In ratio of 6. The InSb material grown under this condition has the smallest FWHM, indicating the best crystal quality. At the same time, the highest electron mobility measured at room temperature is 38860 cm² V⁻¹ s⁻¹. The transport properties and crystal quality of InSb/Al_xIn_1-xSb heterostructures corresponding to different Al compositions are also studied. The results show that as the Al component increases, dislocation scattering caused by lattice mismatch affects the electron mobility of the channel layer. The highest electron mobility of InSb/Al_xIn_1-xSb heterostructures obtained is 18900 cm² V⁻¹ s⁻¹ at room temperature.

In this paper, Zr:Dy:LiNbO₃ crystals are prepared by traditional pull-up method, in which Zr⁴⁺ doping concentrations are 0, 1, 2, and 4 mol%, respectively. In this paper, the defective structure of Zr:Dy:LiNbO₃ crystals and their resistance to photodamage under different Zr⁴⁺ concentration doping are studied. Firstly, the influence of Zr⁴⁺ doping concentration on the defective structure of Zr:Dy:LiNbO₃ crystal and the occupancy of doped ions under different Zr⁴⁺ concentrations are tested and discussed by infrared (IR) absorption spectroscopy and ultraviolet-visible near-infrared (UV–vis–NIR) absorption spectroscopy. The Judd–Ofelt theoretical analysis results show that when the concentration of doped Zr⁴⁺ is 2 mol%, the spectral quality factor (X) of Dy³⁺ in lithium niobate crystals is significantly improved compared with that of Dy³⁺ in other crystals. Secondly, resistance to photodamage of Zr:Dy:LiNbO₃ crystals is studied and analyzed by the light scattering exposure energy flow threshold method. The results show that when the concentration of doped Zr⁴⁺ ions reaches 4 mol%, the exposure energy value is increased by 210 times compared with the no doping, which greatly improves the anti-photodamage performance of the crystal.

Cocrystallization can change the physicochemical and pharmacokinetic properties of active pharmaceutical ingredients (API) and improve biological activities. This study focuses on the documented biological activities of APIs in cocrystal form, specifically those with anticancer properties. Additionally, the mechanisms by which these APIs exhibit modified anticancer effects are discussed. Generally, this technique can change anticancer activity through solubilization, enhancing dissolution rate, permeability improvement, stabilization, producing a slow-release form, and retaining transient in solution and interaction with receptors.

Carbamazepine (CBZ), a widely used antiepileptic drug, is known for its therapeutic efficacy but exhibits suboptimal physicochemical characteristics, including limited bioavailability, low solubility, and poor dissolution rates. In recent years, cocrystallization has emerged as a promising approach to improve these properties and enhance the overall performance of CBZ. This review paper presents a comprehensive exploration of the advances in CBZ cocrystals, focusing on their role in enhancing bioavailability, solubility/dissolution rates, morphology, and stability compared to raw CBZ. It delves into the in-depth examination of computational techniques, such as molecular modelling and crystal structure prediction, that play a pivotal role in the rational design and prediction of CBZ cocrystals, thereby expediting the development process. Additionally, the morphological attributes of CBZ cocrystals are discussed, shedding light on how the unique crystal structures affect their physical properties. Stability is another critical aspect addressed in this review, encompassing thermal, physical, and chemical stability. The thermal behavior of CBZ cocrystals is analyzed through differential scanning calorimetry (DSC), and their crystal structures are characterized by techniques such as X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FTIR). These analyses reveal the stability and structural changes of CBZ cocrystals under various conditions, providing valuable insights for formulation and storage. In summary, this comprehensive review paper amalgamates the latest advancements in CBZ cocrystals, demonstrating their capacity to significantly improve bioavailability, solubility, dissolution rates, and stability.