Effects of the band-filling and Fe/Mo disorder on physical properties of Ca_2FeMoO_6

Both the band filling effect and Fe/Mo disorder have a close correlation with the physical properties of the double perovskite Ca2FeMoO6. Two series of Ca2FeMoO6and Nd0.3Ca1.7FeMoO6ceramics sintered at(1050℃, 1200℃, and 1300℃) were specially designed to comparatively investigate the band-filling effect and Fe/Mo disorder on the physical properties of Ca2FeMoO6. The x-ray diffraction indicates that Fe/Mo disorder is sensitive to the sintering temperature. The magnetization behavior is mainly controlled by the Fe/Mo disorder not by the band filling effect, manifested by a close correlation of saturated magnetization(Ms) with the Fe/Mo disorder. Interestingly, magnetoresistance(MR) property of the same composition is dominantly contributed by the grain boundary strength, which can be expressed by the macroscopic resistivity values. However, the band filling effect caused by the Nd-substitution can decrease the spin polarization, and thus suppress the MR performance fundamentally. Contrary to the MR response, the Curie temperature(TC) shows an obvious optimization due to the band filling effect, which increases the carrier density near the Fermi level responsible for the ferromagnetic coupling interaction strengthen. Maybe, our work can provoke further research interests into the correlation of the band-filling effects and Fe/Mo disorder with the physical properties of other Fe/Mo-based double perovskites.

Prenatal ultrasonographic findings in Klippel-Trenaunay syndrome:A case report

BACKGROUND Klippel-Trenaunay syndrome(KTS)is a rare congenital disorder.A detailed prenatal ultrasound examination plays an important role in the diagnosis of KTS and the subsequent counseling and follow-up of the patient.CASE SUMMARY A 25-year-old woman attended our department for a regular examination.The whole of the right lower extremity and right buttock were observed to be markedly thicker compared to the left one at 18 wk of gestation.However,the lengths of the right femur,tibia and fibula were in the normal range.No marked edema and fluid/cystic spaces were detected in the lower limbs.There were no other organ abnormalities.The vasculature in the right limb was visibly dilated,with much higher intensive blood flow signals.No congenital embryonic veins were visible in both limbs.The right lower limb exhibited much more hypertrophy compared to the left limb two weeks later.Amniocentesis and genetic tests showed normal results with 46 XX.Despite the normal karyotype,the family opted to terminate the pregnancy.The post-mortem examination confirmed asymmetric hypertrophy of the right limb in the fetus and revealed a large area of marked dark-purple superficial capillary malformations occupying the skin of the right lower extremity.The enlargement of veins and soft tissue hypertrophy were also seen on postnatal X-ray and Magnetic Resonance Imaging.Autopsy revealed severe congestion in the right lower limb.A final diagnosis of KTS was made.CONCLUSION KTS may be diagnosed prenatally based on the typical features observed during ultrasound examination.

Quadratic Kernel-Free Least Square Twin Support Vector Machine for Binary Classification Problems

In this paper,a new quadratic kernel-free least square twin support vector machine(QLSTSVM)is proposed for binary classification problems.The advantage of QLSTSVM is that there is no need to select the kernel function and related parameters for nonlinear classification problems.After using consensus technique,we adopt alternating direction method of multipliers to solve the reformulated consensus QLSTSVM directly.To reduce CPU time,the Karush-Kuhn-Tucker(KKT)conditions is also used to solve the QLSTSVM.The performance of QLSTSVM is tested on two artificial datasets and several University of California Irvine(UCI)benchmark datasets.Numerical results indicate that the QLSTSVM may outperform several existing methods for solving twin support vector machine with Gaussian kernel in terms of the classification accuracy and operation time.