Extension of a fifth-order intrinsic aberration for a soft x-ray and vacuum ultraviolet optical system from a one- to two-dimension field light source.

Based on the fifth-order intrinsic aberration of a soft x-ray and vacuum ultraviolet (XUV) optical system with a one-dimension field light source, it is extended to the case of two-dimension in this paper, and the corresponding aberration calculation method is studied. Firstly, we derived sixth-order intrinsic wave aberration expressions of these kinds of optical systems with the aperture-ray coordinates on the reference exit wavefront; and then, derived the calculation expressions for fifth-order intrinsic aberration on the image plane caused by the contributions of wave aberration and defocus, respectively. Finally, the aberration expressions derived in this paper are applied to calculate the aberration distributions of two design examples of these kinds of optical systems, and these calculation results are compared with the ray-tracing program Shadow to validate the aberration expressions. The study shows that the calculation accuracy of aberration expressions is very satisfactory.

Fifth-order intrinsic aberration calculation method for soft x-ray and vacuum ultraviolet optical systems.

In this paper, we propose the fifth-order intrinsic aberration calculation method for soft x-ray and vacuum ultraviolet optical systems. First, the sixth-order intrinsic wave aberrations with the aperture-ray coordinates on the optical surface are derived based on the wave aberration method, and then applying the sixth-order mapping relationship of aperture-ray coordinates between the optical surface and the reference exit wavefront, the expressions with those on the reference exit wavefront can be obtained. Second, we derived the calculation expression for the fifth-order intrinsic aberration on the image plane. Finally, the fifth-order intrinsic aberration calculation expressions of the soft x-ray and vacuum ultraviolet optical system derived in this paper are applied to calculate the aberration distribution on the image plane of two design examples of this kind of optical system, and the calculation results are compared with the ray-tracing ones with Shadow software to validate the aberration expressions. The study shows that the accuracy of the aberration expressions is satisfactory.

Third-order aberration of soft X-ray optical systems with orthogonal and coplanar arrangement of the main planes of elements.

A third-order aberration analytical analysis method of soft X-ray optical systems with orthogonal and coplanar arrangement of the main planes of elements is proposed. Firstly, the transfer equations of the aperture ray and the principle ray are derived; then, based on the third-order aberration theory with the aperture-ray coordinates on the reference exit wavefront of a plane-symmetric optical system, the aberration expressions contributed by the wave aberration and defocus of this kind of optical system are studied in detail. Finally, the derived aberration calculation expressions are applied to calculate the aberration of two design examples of such types of optical systems; the images are compared with ray-tracing results obtained using the Shadow software to validate the aberration expressions. The study shows that the accuracy of the aberration expressions is satisfactory. The analytical analysis method of aberration is helpful in the design and optimization of the soft X-ray optical systems with orthogonal and coplanar arrangement of the main planes of optical elements.

Psychometric properties of the modified breastfeeding self-efficacy scale-short form (BSES-SF) among Chinese mothers of preterm infants.

OBJECTIVE: Preterm mother-infant dyads face more challenges than healthy term infants in breastfeeding initiation and continuation due to maternal health status, preterm infant's immaturity or comorbidities, and breastfeeding policy of the neonatal units. Breastfeeding self-efficacy affects breastfeeding outcomes in preterm infants. No specific instrument in Chinese is available to assess maternal breastfeeding self-efficacy of preterm infants. This study aims to assess the psychometric characteristics of the modified Breastfeeding Self-Efficacy Scale-Short Form (BSES-SF) among Chinese mothers of preterm infants. DESIGN: A cross-sectional study was conducted. SETTING: Two tertiary hospitals in China. PARTICIPANTS: A total of 153 women who gave birth before 37 weeks of gestation. MEASUREMENTS: The instrument was translated and back translated. The internal consistency reliability was investigated using Cronbach's alpha coefficient. The content validity, construct validity, and criterion validity were conducted to evaluate the validity of the scale. Exploratory factor analysis was used to investigate the factor structure. FINDINGS: The scale had good reliability with Cronbach´s alpha above the acceptable level of 0.7. The Item-Content Validity Index (I-CVI) ranged from 0.800 to 1.000, and the Scale-Content Validity Index (S-CVI) is 0.950. The principal component analysis revealed the presence of two factors with eigenvalues greater than 1, explaining a total variance of 74.665%. The modified BSES-SF scores were correlated with women's parity, breastfeeding knowledge, previous breastfeeding experience, perceived support from the spouse and health professionals, and amounts of expressed milk. KEY CONCLUSIONS AND IMPLICATIONS FOR PRACTICE: The Chinese version of modified BSES-SF is a reliable, valid screening instrument to evaluate the maternal breastfeeding self-efficacy of preterm infants. It is recommended to provide interactive, face-to-face breasting education and support to help mothers of preterm infants maintain high level of breastfeeding self-efficacy and further to achieve satisfactory breastfeeding outcomes.

Method of calculating the aberrations of soft X-ray and vacuum ultraviolet optical systems.

Based on the the third-order aberration theory of plane-symmetric optical systems, this paper studies the effect on aberrations of the second-order accuracy of aperture-ray coordinates and the extrinsic aberrations of this kind of optical system; their calculation expressions are derived. The resultant aberration expressions are then applied to calculate the aberrations of two design examples of soft X-ray and vacuum ultraviolet (XUV) optical systems; images are compared with ray-tracing results using SHADOW software to validate the aberration expressions. The study shows that the accuracy of the aberration expressions is satisfactory.