The characteristics of potassium dihydrogen phosphate (KDP) crystals with the Cr(NO3)3 doping at ～10 ppm level were studied by the ultraviolet-visible (UV-Vis) absorption spectrum, electron paramagnetic resonance spectroscopy (EPR), and...

Defects are considered as one of the important factors affecting the quality and laser-induced damage threshold of potassium dihydrogen phosphate (KH 2 PO 4 , KDP). In this study, hybrid density functional theory is used to investigate how the Zn 2+ ions affect the properties of KDP crystal. Since crystal defects often do not exist singly but combine with each other to form clusters, two charge-compensated defect clusters, Zn K + (Zn 2+ ion substitutes K + ion)+ V K − (potassium vacancy)and Zn K + + V H − (hydrogen vacancy) are modeled in this work to investigate the stability of them, the defect states induced by these defects and the mechanisms of the structural breakdown. Zn 2+ ions have a slight effect on the electronic property and linear optical absorption of KDP crystal. With the increase of Zn 2+ concentration, more defect pairs are generated, which causes the deformation of more O─H bonds linking to PO 4 and then the crystal structure becomes unstable. The laser-induced damage resistance of the KDP crystalis affected due to the instability of crystal structure.

A series of 98% deuterated DKDP crystals were grown in solutions with different pD values (2.9, 3.3, 3.8, and 4.3) using the rapid growth method. Samples were cut along the z-direction and fourth-harmonic-generation (FHG) direction which contained both pyramidal and prismatic regions. The nonlinear absorption (NLA) coefficient β of 98% deuterated DKDP crystals was obtained using the Z-scan method operated at the FHG wavelength (266 nm) of a picosecond Nd:YAG laser. According to the results, the nonlinear absorption at 266 nm could be identified as two-photon absorption. The β values of crystal grown in the solution with 3.3 pD value were higher than those of crystals grown in solutions with other pD values under higher laser fluence. The results also indicated that FHG device samples should be prepared from the pyramidal region due to its lower β value. This work will help optimizing the application of 98% DKDP crystals as FHG elements in high-power laser systems.

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Prediabetes presents a high-risk state for the development of various diseases and is reversible by adhering to a healthy lifestyle. We conducted this analysis to explore the associations of the Healthy Eating Index-2015 (HEI-2015) and the Alternate Mediterranean Diet Index (aMed index) with the risk of prediabetes. The data were derived from the National Health and Nutrition Examination Survey, including 20,844 participants. Multivariable-adjusted odds ratios (OR) of prediabetes and 95% confidence intervals (CI) by tertile of diet quality scores were estimated using a weighted logistic regression. Compared to those in the lowest tertile, the multivariable-adjusted OR of prediabetes for the highest tertile was 0.82 (95% CI: 0.72, 0.94; p for trend = 0.005) for HEI-2015 and 0.87 (95% CI: 0.76, 0.98; p for trend = 0.02) for the aMed index. After mutual adjustment, the association for HEI-2015 (p for trend = 0.03) but not for the aMed index (p for trend = 0.59) remained significant. Among the component food groups and nutrients, higher intakes of red and processed meat, sodium, and total saturated fatty acids were associated with a higher risk of prediabetes, while moderate alcohol consumption was associated with a lower risk. In conclusion, adherence to the 2015–2020 Dietary Guidelines for Americans, as compared with the Mediterranean Diet, appeared to be more strongly associated with a lower risk of prediabetes among adults in the United States.