Diurnal Variations of Summer Precipitation in the Beijing Area and the Possible Effect of Topography and Urbanization

The present study examined the diurnal variations of summer precipitation in the Beijing area by using subdaily precipitation and wind observations.A combined effect of topography and urbanization on the characteristics of diurnal variations was suggested.It was shown that stations located in the plain area exhibited typical night rain peaks,whereas those in the mountainous area exhibited clear afternoon peaks of precipitation diurnal variations.The precipitation peaks were associated with wind fields around the Beijing area,which were found to be highly modulated by mountain-valley circulation and urban-country circulation.The lower-tropospheric wind exhibited a clear diurnal shift in its direction from north at 0800 LST to south at 2000 LST,which reflected mountain-valley circulation.The transitions from valley to mountain wind and the opposite generally happened after sunset and sunrise,respectively,and both occurred earlier for the stations located closer to mountains.By comparing the diurnal variations of precipitation at stations in a northeast suburb,an urban area,and a southwest suburb,it was revealed that the northeast suburb group had the highest normalized rainfall frequency,but the southwest group had the lowest from late afternoon to late evening.On the contrary,in the early morning from about 0200 to 1000 LST,the southwest group and urban group had the highest normalized rainfall frequency.This pattern might originate from the combined effects of mountain-valley topography and urbanization.     

Erratum to： An advanced segmentation using area and boundary tracing technique in extraction of lungs region

Erratum to：J.Cent.South Univ.（2014）21：3811-3820DOI：10.1007/s11771-014-2366-9The original version of this article unfortunately contained three mistakes.The mistakes are corrected as follows：1）The spelling of third author is incorrect.The correct name is Jae-Young PYUN.2）The information of corresponding author is incorrect.The correct information should be Goo-Rak KWON,Professor,PhD;Tel/Fax：＋98-711-7264102;E-mail：grkwon@chosun.ac.kr     

Surface characteristics of HA coated Ti-Hf binary alloys after nanotube formation

Ti-Hf binary alloys contained 10%, 20%, 30% and 40% (mass fraction)Hf were manufactured in the vacuum furnace system. And then, specimens were homogenized for 24 h at 1 000 °C in argon atmosphere. The formation of oxide nanotubes was conducted by anodic oxidation on the Ti-Hf alloy in 1 mol/L H₃PO₄ electrolytes containing small amounts of NaF at room temperature. The hydroxyapatite (HA) coating made of tooth ash prepared by electron-beam physical vapor deposition (EB-PVD) method. The corrosion behaviors of the specimens were examined through potentiodynamic test in 0.9% NaCl solution by potentiostat. The microstructures of the alloys were examined by field emission scanning electron microscopy (FE-SEM) and x-ray diffractometer (XRD). It was observed that the lamellar structure translated to needle-like structure with Hf contents. Nanotube formed and HA coated Ti-xHf alloys had a good corrosion resistance.     

Cobalt chloride stimulates phosphoinositide 3-kinase/Akt signaling through the epidermal growth factor receptor in oral squamous cell carcinoma

Tumor cells are often found under hypoxic conditions due to the rapid outgrowth of their vascular supply, and, in order to survive hypoxia, these cells induce numerous signaling factors. Akt is an important kinase in cell survival, and its activity is regulated by the upstream phosphoinositide 3-kinase (PI3K) and receptor tyrosine kinases (RTKs). In this study, we examined Akt activation and RTKs/PI3K/Akt signaling using the hypoxia-mimetic cobalt chloride in oral squamous carcinoma cells. Cobalt chloride increases Akt phosphorylation in both a dose- and time-dependent manner. Blocking the activation of the PI3K/Akt pathway using LY294002 abolished Akt activation in response to cobalt chloride, suggesting that Akt phosphorylation by cobalt chloride is dependent on PI3K. In addition, activation of the PI3K/Akt pathway seems to rely on the epidermal growth factor receptor (EGFR), since the inhibition of EGFR attenuated cobalt chloride-induced Akt activation. The results in this study also demonstrate that cobalt chloride increases EGFR protein levels and induces oral squamous cell carcinoma cells to enter S phase.     

An approximation method for performance analysis of assembly/disassembly systems with parallel-machine stations

This note presents an efficient approximation method to evaluate the performance of tree-structured Assembly/Disassembly (AD) systems in which each station consists of multiple identical machines. It is assumed that the times to failure, times to repair, and processing times are exponentially distributed and the capacities of the buffers are finite. The method transforms an AD system with parallel machines in each station to an (approximately) equivalent AD system with a single machine in each station. After the transformation, a decomposition algorithm is used to analyze the performance of the transformed system. The results of computational experiments show that the suggested method gives good estimates in a short time.     

PIEZOELECTRIC PROPERTIES OF ((Na0.5K0.5)1−xLix)(Nb0.8Ta0.2)O3 CERAMICS

ABSTRACT

In the ((Na_0.5K_0.5)_1?x)Li_x)(Nb_0.8Ta_0.2)O₃ (NKLNT) system, dense ceramics were developed by conventional sintering process. The electrical properties of NKLNT ceramics were investigated as a function of Li substitution. When the sample sintered at 1100°C for 4 h with the substitution of 2 mol% Li at the morphotropic phase boundary, electro-mechanical coupling factor (k_P) and piezoelectric coefficient (d₃₃) were found to reach the highest values of 0.42 and 210 pC/N, respectively. These excellent piezoelectric and electromechanical properties indicate that this system is potentially good candidate for lead-free material for a wide range of electro-mechanical transducer applications.     

Growth and Ferroelectric Characterization of Cerium-Modified Bismuth Titanate Thin Film Deposited on GaN Substrate by Pulsed Laser Deposition

Cerium-modified Bi₄Ti₃O₁₂ thin films were deposited on GaN substrates by the pulsed laser deposition method. The substrate temperature was varied from 600°C to 750°C in 50°C steps. The surface topographies and orientations of the Bi_0.4Ce_0.6Ti₃O₁₂ (BCeT) films were gradually changed in proportion to the substrate temperature. The diffusion reaction between BCeT and the GaN layer and the depth profiles of the films were investigated by Auger electron spectroscopy (AES). The ferroelectric properties and leakage current characteristics of the metal-ferroelectric-GaN stacked thin films were measured and discussed.     

27Al MAS-NMR study of inorganic polymer formation at ambient temperature

Inorganic polymers are a novel class of materials formed by the polymerization of silicon, aluminium and oxygen species to form an amorphous three-dimensional framework structure. The basis of this process is the alkaline solutions to induce a certain amount of Si and Al atoms to dissolve from a feedstock such as aluminosilicate. A study of ²⁷Al MAS-NMR was carried out in an attempt to understand the reaction mechanism of the inorganic polymerization at ambient temperature. Scanning electron microscopy (SEM) and X-ray diffractometry (XRD) were also employed to establish the composition and microstructure of the inorganic polymerization. Specimens were prepared with different Al/Si mole ratios from the starting materials. The higher the Al content, the more sufficient the Al atoms that can combine with SiO₄, and the longer the reaction time, the more the bonded Si-O-Al-O polymer structure, and then the higher the Al content, the fewer the octahedral Al with a uniform Si-O-Al-O structure in four directions, because four Al atoms are combined with SiO₄, resulting in a uniform Si-O-Al-O structure in four directions. The results show that they have an amorphous microstructure.     

Genetic algorithm tuned PI controller on PMSM simplified vector control

A simple control structure in servo system is occasionally needed for simple industrial application which precise and high control performance is not exessively important so that the cost production can be reduced efficiently. Simplified vector control, which has simple control structure, is utilized as the permanent magnet synchronous motor control algorithm and genetic algorithm is used to tune three PI controllers used in simplified vector control. The control performance is obtained from simulation and investigated to verify the feasibility of the algorithm to be applied in the real application. Simulation results show that the speed and torque responses of the system in both continuous time and discrete time can achieve good performances. Furthermore, simplified vector control combined with genetic algorithm has a similar perfofmance with conventional field oriented control algorithm and possible to be realized into the real simple application in the future.     

EXTRACTION, FRACTIONATION AND ACTIVITY CHARACTERISTICS OF PROTEASES FROM SHRIMP PROCESSING DISCARDS

Proteases recovered from Northern pink shrimp (NPS) and Southern rough shrimp (SS) processing discards (heads, shells, tails) were characterized. Shrimp processing discards were extracted with water following homogenization and centrifugation in order to obtain the crude extract which was subsequently fractionated with solid ammonium sulfate. Two fractions sedimenting with 30–50% (designated as NPS‐I and SS‐I), and 50–70% (designated as NPS‐II and SS‐II) ammonium sulfate were collected following centrifugation, respectively. Endoprotease activity of the crude extract was 0.02 U/mg for hemoglobin (Hb, pH 3.0), 0.16 U/mg for azocasein (Ac, pH 6.0) and 0.12 U/mg for benzoyl‐Arg‐β‐naphthylamide (BANA, pH 7.0). The exoprotease activity was 0.11–0.17 U/mg for Arg‐β‐naphthylamide (ArgNA, pH 7.0), 0.06–0.11 U/mg for Lys‐β‐naphthylamide (LysNA, pH 7.0) and 0.08–0.09 U/mg for Leu‐β‐naphthylamide (LeuNA, pH 7.0). Endoprotease activity increased 5–7.4 fold for NPS‐I and SS‐I, and 1.9–2.7 fold for NPS‐II and SS‐II against crude extract. Meanwhile, exoprotease activity increased 3.6–4.8 fold for NPS‐I and SS‐I, and 5.6–7.2 fold for NPS‐II and SS‐II. Meat treated with NPS‐I and SS‐I was tenderized more extensively than that treated with NPS‐II and SS‐II. The results of this study suggest that proteases recovered from shrimp processing discards may potentially be used as processing aids in formulated foods.