"Nanoscale lattice fence" in a metal-organic framework: interplay between hinged topology and highly anisotropic thermal response

A thermoresponsive, 3D hinged metal-organic framework (HMOF-1) assembled from meso-tetra(4-pyridyl)porphine and CdI(2) exhibits a 3D "lattice fence" topology with extraordinary thermal expansion and shrinkage. A simple structural model is established to elucidate such a drastic thermal response. The hinged structure model presented here can also be applied to other "lattice fence" topologies with little or no modification, depending on the symmetry of the molecular building blocks.     

Hilbert�CSchmidt differences of composition operators on the Bergman space

In the setting of the weighted Bergman space over the unit disk, we characterize Hilbert?CSchmidt differences of two composition operators in terms of integrability condition involving pseudohyperbolic distance between the inducing functions. We also show that a linear combination of two composition operators can be Hilbert?CSchmidt, except for trivial cases, only when it is essentially a difference. We apply our results to study the topological structure of the space of all composition operators under the Hilbert?CSchmidt norm topology. We first characterize components and then provide some sufficient conditions for isolation or for non-isolation.     

A Comparison of the Prospective Acquisition Correction Technique with Respiratory Triggering Technique in a 3-D MR Pancreaticobiliary System Angiography: A Focus on Normal Healthy Subjects

This study aimed at comparing the quality of images produced using the prospective acquisition correction (PACE) technique based on a navigator with that produced by the respiratory triggering (RT) technique based on a wireless respiratory triggering cushion. Twenty normal healthy people underwent magnetic resonance (MR) cholangiopancreatography based on a three-dimensional (3-D) respiratory triggering technique using either the PACE or RT techniques. For quantitative analysis, the signal-to-noise and contrast-to-noise ratios were calculated. For qualitative analysis, the morphology of the anatomical structures, artifacts due to respiration and the definition of cholangiopancreatography were evaluated based on the following five-point scale. The excellence of the images was also evaluated independently by two specialists in abdominal imaging and two radiological technicians, whose results were analyzed statistically using a Wilcoxon signed-rank test. With regard to the morphology of the anatomical structures and sharpness of the pancreaticobiliary tract, the PACE technique had higher scores than the RT one (P?=?0.07). However, there were no significant differences in artifacts due to respiration between the two techniques (P?=?0.774). The signal-to-noise and contrast-to-noise ratios were significantly higher in the PACE technique (P?<?0.05), with the exception of the common hepatic duct (P?=?0.085). A comparison was made between the PACE and RT techniques in respiratory triggering 3-D MR cholangiopancreatography, which showed that the PACE technique produces a higher image quality.     

Correlation between Hepatic Fat Content Using 3-Echo 3-D Dixon Method and Intravoxel Incoherent Motion (IVIM) Perfusion MR Imaging

Fat accumulates as droplets in the hepatocyte swelling, distortion of microcirculatory anatomy and compression of sinus. This study aims to investigate the correlation between the T2*-corrected fat fraction (FF) value acquired via gradient echo with a low flip angle and parenchymal pseudorandom blood perfusion (P _fraction), microcirculation (D _fast), and slow component of diffusion (D _slow), acquired via intravoxel incoherent motion (IVIM), and to investigate the blood microcirculation and diffusion components of liver parenchyma, according to fat deposition. A total of 126 patients underwent 3-T magnetic resonance imaging, including a 3-echo three-dimensional (3-D) gradient echo sequence with T2*-corrected Dixon reconstruction and IVIM sequence. Pearson’s correlation analysis was conducted to investigate the correlation of the FF obtained via the Dixon method with the apparent diffusion coefficient (ADC), D _slow, P _fraction, and D _fast obtained via IVIM. Correlation analysis was also conducted for the IVIM mapping images. A confidence level of p < 0.05 was set. A negative correlation was found between the T2*-corrected FF acquired using the 3-echo 3-D Dixon method and D _slow acquired via IVIM (r = ?0.181, p < 0.05). It was likely due to the increased extracellular collagen deposition and increased intracellular fat droplets during the progression of liver fibrosis.     

A Method for Predicting the Parameters of Plastic Deformation of Dispersedly Reinforced Materials by Using a Modified Mori–Tanaka Model

Mechanics of Composite Materials - A modified Mori–Tanaka model to predict the average mechanical characteristics for dispersedly reinforced materials considering the physical nonlinearity,...     

Environmentally friendly electroless plating for Ag/TiO2-coated core–shell magnetic particles using ultrasonic treatment

In this work, high-reflectance brilliant white color magnetic microspheres comprising a Fe/TiO₂/Ag core–shell structure with a continuous, uniform compact silver layer were successfully fabricated by TiO₂-assisted electroless plating in a simple and eco-friendly method. The coating procedure for TiO₂ and Ag involved a sol–gel reaction and electroless plating with ultrasound treatment. The electroless plating step was carried out in an eco-friendly manner in a single process without environmentally toxic additives. The TiO₂ layer was used as a modification layer between the Fe microspheres and the silver layer to improve adhesion. A continuous and compact silver layer could be formed with a high degree of morphological control by introducing ultrasonication and adjusting the ammonium hydroxide concentration.     

Preliminary result of an advanced tangential X-ray pinhole camera system with a duplex MWPC on KSTAR plasma

An advanced tangential X-ray pinhole camera (TXPC) has been developed for KSTAR by utilizing a 2-D duplex multi-wire proportional counter (MWPC) detector. The KSTAR MWPC employs a 2-D parallel type readout system for high temporal resolution and adopts a duplex type for the capability of electron temperature measurement via the multi-color method. This paper presents the performance test result of the developed MWPC system utilizing a Fe-55 X-ray source. As a preliminary experimental result from the 2012 KSTAR campaign, the clear presentation of sawtooth activities and its frequency change, and 2-D plasma images during the vertical disruption event are given.     

Structural studies on the yttrium-doped cobalt ferrite powders synthesized by sol–gel combustion method

Y_0.2CoFe_1.8O₄ nanopowders were prepared using a sol–gel combustion method. Metal nitrates, such as yttrium nitrate, cobalt nitrate and ferric nitrate, were used as the source materials. Citric acid and polyvinyl alcohol were used as the burning agent and agglomeration reducing agent, respectively. The pH of the precursor was maintained at 7. The mean crystallite size of the prepared ferrite was in the range of ∼20–70 nm. The inverse spinel structure, cubic morphology, and the identification of functional groups of the yttrium-doped cobalt ferrite were analyzed systematically using several analytical tools.     

A flexible metamaterial with negative refractive index at visible wavelength

In this paper, we demonstrated a realization of a flexible metamaterial with negative refractive index operating at visible wavelength. With the help of Finite-Difference Time-Domain (FDTD) method, we could establish design rules for the metamaterial and analyze the characteristics of it. To this end, the fishnet structure with the unit cell size 185 nm by 240 nm was fabricated. Due to the polymer dielectric spacer between the metal-layers, the metamaterial is freestanding without base substrate and additional backside etching process.     

Harmonic Bergman functions as radial derivatives of Bergman functions

In the setting of the half-space of the euclidean -space, we show that every harmonic Bergman function is the radial derivative of a Bergman function with an appropriate norm bound.