Broadband High-Gain SIW Cavity-Backed Circular-Polarized Array Antenna

© 2016 IEEE. A circularly polarized (CP) 4 × 4 array antenna based on substrate integrated waveguide (SIW) technology is presented. Circular polarization is achieved by applying the sequential rotation technique (SRT) with a well-designed sequential feed network and linear-polarized array elements. The proposed 4 × 4 array has a wide axial ratio (AR) bandwidth of 14% from 18.3 to 21.1 GHz with gain > 13 dBic. Then, the array is expanded to achieve higher gains. A 16 × 16-element array is designed, fabricated, and tested. Test results show that the 16 × 16 array has an AR bandwidth of 13.8% from 18.5 to 21.25 GHz and a peak gain of 25.9 dBic at 20.5 GHz

Phase diagram and spin-glass phenomena in electron-doped La1-xHfxMnO3 (0.05 ≤ x ≤ 0.3) manganite oxides

The effects of tetravalent hafnium doping on the structural, transport, and magnetic properties of polycrystalline La1−xHfxMnO3 (LHMO) (0.05 ≤ x ≤ 0.3) were investigated systematically. LHMO exhibited a typical colossal magnetoresistance effect via the double-exchange between Mn2+ and Mn3+ ions, instead of that between Mn3+ and Mn4+ ions in hole-doped manganites. A phase diagram was obtained for the first time through magnetization and resistance measurements in a broad temperature range. As the Hf concentration varied from x = 0.05 to 0.3, the Curie point and metal-to-insulator transition temperature increased significantly, whereas the magnetization and resistivity decreased remarkably. An abnormal enhancement of the magnetization was observed at about 42 K. It was further confirmed that a second magnetic phase MnO2 in LHMO gives rise to such a phenomenon. The possible causes are discussed in detail. The dynamic magnetic properties of LHMO, including relaxation and aging processes, were studied, demonstrating a spin-glass state at low temperature accompanied by a ferromagnetic phase.published_or_final_versio

Clinical significance of VEGF-A, -C and -D expression in esophageal malignancies

Vascular endothelial growth factors ( VEGF)- A, - C and - D are members of the proangiogenic VEGF family of glycoproteins. VEGF-A is known to be the most important angiogenic factor under physiological and pathological conditions, while VEGF-C and VEGF-D are implicated in the development and sprouting of lymphatic vessels, so called lymphangiogenesis. Local tumor progression, lymph node metastases and hematogenous tumor spread are important prognostic factors for esophageal carcinoma ( EC), one of the most lethal malignancies throughout the world. We found solid evidence in the literature that VEGF expression contributes to tumor angiogenesis, tumor progression and lymph node metastasis in esophageal squamous cell carcinoma ( SCC), and many authors could show a prognostic value for VEGF-assessment. In adenocarcinoma (AC) of the esophagus angiogenic properties are acquired in early stages, particularly in precancerous lesions like Barrett's dysplasia. However, VEGF expression fails to give prognostic information in AC of the esophagus. VEGF-C and VEGF-D were detected in SCC and dysplastic lesions, but not in normal mucosa of the esophagus. VEGF-C expression might be associated with lymphatic tumor invasion, lymph node metastases and advanced disease in esophageal SCC and AC. Therapeutic interference with VEGF signaling may prove to be a promising way of anti-angiogenic co-treatment in esophageal carcinoma. However, concrete clinical data are still pending

Heterostructured electrode with concentration gradient shell for highly efficient oxygen reduction at low temperature

Heterostructures of oxides have been widely investigated in optical, catalytic and electrochemical applications, because the heterostructured interfaces exhibit pronouncedly different transport, charge, and reactivity characteristics compared to the bulk of the oxides. Here we fabricated a three-dimensional (3D) heterostructured electrode with a concentration gradient shell. The concentration gradient shell with the composition of Ba0.5-xSr0.5-yCo0.8Fe0.2O3-δ (BSCF-D) was prepared by simply treating porous Ba0.5Sr0.5Co0.8Fe0.2O3-δ (BSCF) backbone with microwave-plasma. Electrochemical impedance spectroscopy reveals that the oxygen surface exchange rate of the BSCF-D is enhanced by ~250% that of the pristine BSCF due to the appearance of the shell. The heterostructured electrode shows an interfacial resistance as low as 0.148 Ω cm2 at 550°C and an unchanged electrochemical performance after heating treatment for 200 h. This method offers potential to prepare heterostructured oxides not only for electrochemical devices but also for many other applications that use ceramic materials

Observation of a ppb mass threshoud enhancement in \psi^\prime\to\pi^+\pi^-J/\psi(J/\psi\to\gamma p\bar{p}) decay

The decay channel $\psi^\prime\to\pi^+\pi^-J/\psi(J/\psi\to\gamma p\bar{p})$ is studied using a sample of $1.06\times 10^8$ $\psi^\prime$ events collected by the BESIII experiment at BEPCII. A strong enhancement at threshold is observed in the $p\bar{p}$ invariant mass spectrum. The enhancement can be fit with an $S$-wave Breit-Wigner resonance function with a resulting peak mass of $M=1861^{+6}_{-13} {\rm (stat)}^{+7}_{-26} {\rm (syst)} {\rm MeV/}c^2$ and a narrow width that is $\Gamma<38 {\rm MeV/}c^2$ at the 90% confidence level. These results are consistent with published BESII results. These mass and width values do not match with those of any known meson resonance.Comment: 5 pages, 3 figures, submitted to Chinese Physics

Surgical treatment of congenital biliary duct cyst

<p>Abstract</p> <p>Background</p> <p>It is acknowledged that total cyst excision is a safe and ideal surgical treatment for congenital biliary duct cyst, compared to simple internal drainage. The aim of this study was to determine the optimal operation occasion and the effect of laparoscopy on congenital biliary duct cyst based upon total cyst excision.</p> <p>Methods</p> <p>From January 2002 to January 2011, 217 patients were admitted to Southwest Hospital for congenital biliary duct cyst. To determine the optimal surgery occasion, we divided these subjects into three groups, the infant group (age ≤ 3 years), the immaturity group (3 < age ≤ 18 years), and the maturity group (age > 18 years), and then evaluated the feasibility, risk and long-term outcome after surgery in the three groups. To analyze the effect of laparoscopic technique on congenital biliary duct cyst, we divided the patients into the laparoscopy and the open surgery groups.</p> <p>Results</p> <p>Among the three groups, the morbidity from cholangiolithiasis before surgical treatment had obvious discrepancy (p < 0.05) (lowest in the infant group), and intraoperative blood loss also had apparent diversity (p < 0.05). Furthermore, long-term outcomes (secondary cholangiolithiasis, stoma stenosis and cholangiocarcinoma) showed no significant difference between different groups (p > 0.05).</p> <p>Similarly, no significant discrepancy was observed in the morbidity from postoperative complications or long-term postoperative complications (p > 0.05) between the laparoscopic and the open surgery groups.</p> <p>Conclusions</p> <p>We conclude that total cyst excision should be performed as early as possible. The optimal treatment occasion is the infant period, and laparoscopic resection may be a new safe and feasible minimally invasive surgery for this disease.</p

Magnetism and its microscopic origin in iron-based high-temperature superconductors

High-temperature superconductivity in the iron-based materials emerges from, or sometimes coexists with, their metallic or insulating parent compound states. This is surprising since these undoped states display dramatically different antiferromagnetic (AF) spin arrangements and N$\rm \acute{e}$el temperatures. Although there is general consensus that magnetic interactions are important for superconductivity, much is still unknown concerning the microscopic origin of the magnetic states. In this review, progress in this area is summarized, focusing on recent experimental and theoretical results and discussing their microscopic implications. It is concluded that the parent compounds are in a state that is more complex than implied by a simple Fermi surface nesting scenario, and a dual description including both itinerant and localized degrees of freedom is needed to properly describe these fascinating materials.Comment: 14 pages, 4 figures, Review article, accepted for publication in Nature Physic

Improved Measurements of Partial Rate Asymmetry in B -> h h Decays

We report improved measurements of the partial rate asymmetry (Acp) in B -> h h decays with 140fb^-1 of data collected with the Belle detector at the KEKB e+e- collider. Here h stands for a charged or neutral pion or kaon and in total five decay modes are included: K-+ pi+-, K0s pi-+, K-+ pi0, pi-+ pi0 and K0s pi0. The flavor of the last decay mode is determined from the accompanying B meson. Using a data sample 4.7 times larger than that of our previous measurement, we find Acp(K-+ pi+-) -0.088+-0.035+-0.013, 2.4 sigma from zero. Results for other decay modes are also presented.Comment: 9 pages, 1 figur