Creation of partial band gaps in anisotropic photonic-band-gap structures

The photonic-band-gap (PBG) structure composed of an anisotropic-dielectric sphere in uniform dielectric medium is studied by solving Maxwell’s equations using the plane-wave expansion method. In particular, for a uniaxial material with large principal refractive indices and sufficient anisotropy between them, the photonic band structures possess a full band gap in the whole Brillouin zone for a diamond lattice. Furthermore, in the 1/3 partial Brillouin zone where the Bloch wave vector has a dominant component along the extraordinary axis of uniaxial sphere, the photonic band structures are found to exhibit full band gaps for all the other lattices such as face-centered-cubic, body-centered-cubic, and simple-cubic lattices, although a complete band gap does not open in the whole Brillouin zone. The partial band gaps persist at a very low filling fraction of uniaxial sphere. This phenomenon is attributed to the breakdown of the photonic band degeneracy at high-symmetry points of the Brillouin zone by the anisotropy of material dielectricity. The combination of such an anisotropic PBG structure with the self-arrangement technique of colloidal crystal may provide a possible way to fabricate the three-dimensional photonic crystal in visible and infrared regimes. The application of a strong electric field may bring into alignment the extraordinary axis of uniaxial sphere as this configuration of spheres is most favorable thermodynamically.published_or_final_versio

Influences of processing technique on electrical characteristics of TVS used in communication systems

An improved technique is proposed in fabricating a semiconductor surge protection device which is used in high-speed wideband information transmission systems. In order to increase the surge handling capability of the device, a double p-type diffusion is used. Specifically, in the diffusion step of gallium, SiO2 is used as a mask to obtain a very small base width and to avoid the reduction of carrier lifetime. It is found that this is a very useful way to reduce the on-state voltage drop and therefore the energy dissipation of the device.published_or_final_versio

Effects of chemical composition on humidity sensitivity of Al/BaTiO3/Si structure

Argon-ion-beam sputtering technique has been applied to deposit barium titanate (BaTiO3) films on silicon wafers at room temperature under vacuum, and then Al/BaTiO3/Si structures were fabricated. Results show that the current and capacitance of these devices are sensitive to the change of relative humidity at room temperature, and saturation absorption (response) time as well as humidity sensitivity of the devices depend on the chemical composition of the BaTiO3 films. For higher annealing temperature and longer annealing time, the oxygen composition increases while fixed charge density decreases. These changes result in lower humidity sensitivity and longer response time.© 1995 American Institute of Physics.published_or_final_versio

Randomized Clinical Trial on Preventing Root Caries among Community-Dwelling Elders

Dental root caries is a common disease among elders. More efforts on preventing this disease are needed. Silver diammine fluoride (SDF) is known to prevent dental caries in primary teeth. However, clinical evidence of its efficacy in preventing root surface caries is limited. This clinical trial aimed to compare the effectiveness of SDF in preventing root caries among elders in a water fluoridated area. A total of 323 elders who had at least 5 teeth with exposed root surfaces and who had self-care ability were randomly allocated into 3 intervention groups: group 1 (placebo control), annual application of tonic water; group 2, annual application of SDF solution; group 3, annual application of SDF solution, immediately followed by potassium iodide (KI) solution. Oral hygiene instructions and fluoride toothpaste were provided to all subjects. Status of dental root surface was assessed every 6 mo by the same independent examiner. After 30 mo, 257 (79.6%) elders were reviewed. The mean numbers of root surface with new caries experience in the control, SDF, and SDF/KI groups were 1.1, 0.4, and 0.5, respectively (analysis of variance, P 0.05). Moreover, elders who had higher visible plaque index scores at 30-mo examination (analysis of covariance, P < 0.001) and those who had higher baseline DMFT scores (analysis of covariance, P = 0.005) developed more new root caries. It is concluded that annual application of SDF or SDF/KI solution is effective in preventing root caries among community-dwelling elders in a fluoridated area (ClinicalTrials.gov NCT02360124).postprin

Comparative study on microstructure and surface properties of keratin- and lignocellulosic-based activated carbons

© 2015 Elsevier B.V. All rights reserved. The paper probed the preparation of activated carbon by potassium silicate (K2SiO3) activation from keratin waste (cowhair waste, CW) and lignocellulosic materials (Cyperus alternifolius, CA) and the comparisons of physicochemical properties of the resulting carbons. These impregnation conditions were as follows: one impregnated at room temperature for 12 h then dipped at high temperature for 30 min; the other was only impregnated at room temperature for 12 h, producing four activated carbons CWAC-1, CWAC-2, CAAC-1, and CAAC-2. The influence of activation time, K2SiO3/precursor weight ratio, and the pre-process on properties of activated carbons was discussed. The CWAC-1 produced at 700°C with the K2SiO3/precursor weight ratio of 2:1 possessed the Brunauer-Emmet-Teller (BET) surface area of 1965 m2/g and total pore volume of 1.345 cm3/g, while CAAC-1 prepared at the same conditions attained the BET surface area of 1710 m2/g and total pore volume of 0.949 cm3/g. The surface area and total pore volume of CAAC increased with the impregnation ratio. Moreover, CWAC-1, CWAC-2, CAAC-1, and CAAC-2 exhibited high portion of micropores, illustrating the role of K2SiO3. The analysis with a Fourier transform infrared spectrometer indicates that CWAC has more functional groups than CAAC, as well as CWAC-1 and CWAC-2 which possess similar functional groups

Direct participation in and indirect exposure to the occupy central movement and depressive symptoms: a longitudinal study of Hong Kong adults

postprin

Confucian Principles: A Study of Chinese Americans’ Interpersonal Relationships in Selected Children’s Picturebooks

[[abstract]]There has not been enough critical analysis of children’s literature by and about Chinese Americans, especially when compared to other minority groups in the United States. In particular, Chinese American historical books lack extensive analysis. It is important to reflect cultural accuracy in literature and to help children develop clear concepts of self and others by providing precise cultural and physical characteristics of people. While cultural authenticity allows children the opportunity to see a reflection of real experiences within a book instead of seeing stereotypes or misrepresentations, obtaining correct information about a certain time period can help children to see images of immigration accurately represented in literature. Using the Confucian delineation of interpersonal relationships as the major criterion of cultural authenticity, this article examines three currently available children’s picturebooks set in the historical period between 1848 and 1885. In addition to exploring how Chinese Americans’ interpersonal relationships are portrayed in these children’s historical books, this article argues for more proactive inclusion of the diversity in selection of picturebooks.[[notice]]補正完

The nature of localization in graphene under quantum Hall conditions

Particle localization is an essential ingredient in quantum Hall physics [1,2]. In conventional high mobility two-dimensional electron systems Coulomb interactions were shown to compete with disorder and to play a central role in particle localization [3]. Here we address the nature of localization in graphene where the carrier mobility, quantifying the disorder, is two to four orders of magnitude smaller [4,5,6,7,8,9,10]. We image the electronic density of states and the localized state spectrum of a graphene flake in the quantum Hall regime with a scanning single electron transistor [11]. Our microscopic approach provides direct insight into the nature of localization. Surprisingly, despite strong disorder, our findings indicate that localization in graphene is not dominated by single particle physics, but rather by a competition between the underlying disorder potential and the repulsive Coulomb interaction responsible for screening.Comment: 18 pages, including 5 figure

The disposition and pharmacokinetics of Dioscorea nipponica Makino extract in rats

This study was aimed to investigate the disposition and pharmacokinetics of the total saponins of dioscorea (TSD) in rats. Male Sprague-Dawley rats were orally administrated with 3H labeled TSD at a single dose ratio of 80 mg TSD per 1 kg rat. Blood samples and feces were collected at different time points to measure the level of TSD activity. At the final time point, determination of the disposition of TSD in lung, kidney, heart, liver, adrenal, and small intestine were performed. From the blood samples' emission of radioactivity, pharmacokinetic parameters were derived as T1/2 = 33.33 ± 4.48 h, T max = 6.5 ± 0.71 h, AUC = 119400 ± 421097.67, and C max = 2643.33 ± 192.26 dpm/ml. There was 51.609% of 3H labeled substance excreted in 24 h. These results suggested that blood concentration of 3H-TSD was extremely low and the majority of TSD was excreted in the feces. The TSD was extensively distributed to multitissues. The radioactivity level was measured to be the highest in the liver, adrenal gland, and wall of the gastrointestinal tract. The radioactivity of TSD was still being detected in blood after 96 h. This showed TSD was excreted in vivo very slowly. © 2008 Academic Journals.published_or_final_versio

A new species of Argyromys (Rodentia, Mammalia) from the oligocene of the valley of lakes (Mongolia): its importance for palaeobiogeographical homogeneity across Mongolia, China and Kazakhstan

We describe a new species of Rodentia (Mammalia), Argyromys cicigei sp. nov. from Toglorhoi (fossil bed TGW-A/2a) in Mongolia and Ulantatal (fossil beds UTL 1 and UTL 7) in China. Its tooth morphology differs from the type species Argyromys aralensis from Akespe in Kazakhstan by smaller size and simpler structures. Argyromys has been assigned in different families of Muroidea, such as Tachyoryctoididae and Spalacidae. However, the presence of common characters indicates a closer relationship of Argyromys with the genera of Cricetidae s.l. (subfamilies Eucricetodontinae; Cricetopinae; Cricetodontinae and Gobicricetodontinae among others) from Asia than with the earliest representatives of Spalacidae or the endemic Tachyoryctoididae. Argyromys cicigei sp. nov. possesses a simple anterocone and anteroconid in the upper and lower first molars, respectively, which is characteristic for Cricetidae s.l. It has a flat occlusal surface in worn specimens; weakly-developed posterolophs; an oblique protolophule and metaloph on the upper molars and it lacks a labial anterolophid on the m1. These traits are also typical of the Oligocene genera Aralocricetodon and Plesiodipus, included in the subfamilies Cricetodontinae and Gobicricetodontinae respectively. The cladistic analysis performed here supports this hypothesis. The clade formed by Argyromys species is grouped with other cricetid taxa (s.l). Spalacids, however, form a different clade, as do the tachyoryctoids. Previous authors state that the Aral Formation (Kazakhstan) should be dated to the Oligocene instead of the Miocene, based on the presence of several taxa. The finds of Argyromys in both regions supports the statement that they are closer in age than previously thought. The occurrence of Argyromys in Kazakhstan, Mongolia and China evidences the biogeographic unity of the Central Asian bioprovince during the Oligocene