KNbO3 single crystal growth by the radio frequency heating Czochralski method

A radio frequency heating Czochralski technique to obtain single crystal KNbO3 is first presented. The technological parameters of KNbO3 crystal growth by the Czochralski technique and its pulling conditions were studied in detail. The experiments on second harmonic generation using 1.06 micrometer Nd:YAG laser in KNbO3 have been conducted. The second harmonic efficiency for upconversion of KNbO3 is found to be as high as that of NaBa2Nb5O15. An automatic scanning measurement for the optical homogeneity of KNbO crystal is also described. KNbO3 is revealed to be a potentially useful nonlinear material for optical device applications

建築物生命週期碳排放分析之發展

The artilce can be viewed at: http://www.tcea168.com.tw/075366270/images/files/10956.pdf建造業作為全球碳排放的主要來源之一，在 全球節能減排的趨勢下將發揮舉足輕重的作 用。近年來，爲了推行綠色環保建築，各國 都在積極地發展綠色建築評審標準和認證體 系。然而，這些標準和認證體系很少提及建 築材料和建築設備在生命週期內的碳排放量。 由於缺乏相關的量化和評核基準，建造業在 減少能耗，循環再造等減碳的發展方向上勢 必會受到極大的限制。 本文開頭介紹了相關的綠色建築評審標準和 認證體系，並闡述了這些體系的重點和理念。 由於目前世界上並沒有一個得到廣泛認可和 應用的建築物碳排放計算標準，本文引入了 生命週期分析法（LCA），並重點闡述了其 在建築項目應用時如何設定一個合適的界限 （boundary）。文章亦簡介了一個評估建築 物料隱含碳足蹟的平台，以及碳排放分析在 應用上存在的一些潛在困難。我們希望可以 藉此研究，把建築物的生命週期碳排放分析 和綠色建築評審互相融合，從而為建築項目 由設計、建造到拆卸提供一個更加全面和有 效的環境影響分析評估。這樣也可以幫助業 主或發展商在節能減排方面提供最佳方案

Electronic States and Magnetism of Mn Impurities and Dimers in Narrow-Gap and Wide-Gap III-V Semiconductors

Electronic states and magnetic properties of single $Mn$ impurity and dimer doped in narrow-gap and wide-gap $III$-$V$ semiconductors have been studied systematically. It has been found that in the ground state for single $Mn$ impurity, $Mn$-$As(N)$ complex is antiferromagnetic (AFM) coupling when $p$-$d$ hybridization $V_{pd}$ is large and both the hole level $E_{v}$ and the impurity level $E_{d}$ are close to the midgap; or very weak ferromagnetic (FM) when $V_{pd}$ is small and both $E_{v}$ and $E_d$ are deep in the valence band. In $Mn$ dimer situation, the $Mn$ spins are AFM coupling for half-filled or full-filled $p$ orbits; on the contrast, the Mn spins are double-exchange-like FM coupling for any $p$-orbits away from half-filling. We propose the strong {\it p-d} hybridized double exchange mechanism is responsible for the FM order in diluted $III$-$V$ semiconductors

Oxic and anoxic conditions affect arsenic (As) accumulation and arsenite transporter expression in rice

Arsenic (As) exposure from rice consumption has now become a global health issue. This study aimed to investigate the effects of rice rhizosphere oxic conditions on silicate transporter (responsible for arsenite transportation) expressions, and on As accumulation and speciation in four rice genotypes, including two hybrid genotypes (Xiangfengyou9, Shenyou9586) and two indica subspecies (Xiangwanxian17, Xiangwanxian12). Oxic and anoxic treatments have different effects on root length (p < 0.001) and weight (p < 0.05). Total As concentrations in roots were dramatically lower in oxic treatments (88.8–218 mg/kg), compared to anoxic treatments (147–243 mg/kg) (p < 0.001). Moreover, root and shoot arsenite concentrations in oxic treatments were lower than that in anoxic treatments in arsenite treatments. The relative abundance of silicate transporter expressions displayed a trend of down-regulation in oxic treatments compared to anoxic treatments, especially significantly different for Xiangwanxian17, Xiangwanxian12 in Lsi1 expressions (p < 0.05), Xiangfengyou9, Shenyou9586, Xiangwanxian17 in Lsi2 expressions (p < 0.05). However, there were no significant differences of transporter expressions in different As treatments and genotypes. It may be a possible reason for low As accumulation in rice growing aerobically compared to flooded condition and a potential route to reduce the health risk of As in rice

Effect of arsenic on spatial pattern of radial oxygen loss and iron plaque formation in rice

The effects of different arsenic (As) treatments on spatial pattern of radial oxygen loss (ROL), iron (Fe) plaque formation and As accumulation in rice were investigated using three rice genotypes, planted under greenhouse conditions. Arsenic was applied to soil at 50 and 100 mg/kg, with untreated soil used as a control having an average As concentration of 8.5 mg/kg. It was demonstrated that the ratio of ROL in root tips to that at the root base slightly decreased with increasing As concentration, suggesting that the spatial ROL patterns in these groups may be shifted from the “tight” barrier towards the “partial” barrier form. Furthermore, increasing As concentration led to a increase in Fe plaque formation on root surfaces. In addition, root As concentrations of genotypes in 50 and 100 mg/kg As treatments were significantly higher than that of control treatment (P<0.05). Grain As concentration of genotype Nanyangzhan (with lower ROL) was significantly higher (P<0.05) than that of genotype CNT87059-3 with higher ROL

Expression and Significance of RANTES and MCP-1 in Renal Tissue With Chronic Renal Allograft Dysfunction

AbstractBackgroundTo investigate the expression of RANTES (regulated upon activation, normal T-cell–expressed and –secreted) and monocyte chemoattractant protein–1 (MCP-1) in renal allografts with chronic renal allograft dysfunction (CRAD), and explore its relationship with interstitial fibrosis and tubular atrophy (IF/TA).MethodsAn immunohistochemical assay and computer-assisted, genuine colored image analysis system were used to detect the expression of RANTES and MCP-1 in renal allografts with CRAD. The relationship among the expression level of MCP-1, RANTES, and the grade of inflammatory cell infiltration, interstitial fibrosis, and tubular atrophy in renal allografts were analyzed. Ten specimens of healthy renal tissue were used as controls.ResultsCompared to the normal tissues, the expressions of RANTES and MCP-1 were significantly higher in the renal tissues with CRAD (P < .001), and the expressions tended to increase along with the pathological grade of IF/TA. The expression of RANTES and MCP-1 were positively correlated with the pathological grades of IF/TA (r = 0.940 and 0.954 respectively, P < .001 for both).ConclusionIn renal allograft tissue with CRAD, the up-regulated expressions of RANTES and MCP-1 may be related to the progression of chronic renal allograft dysfunction and allograft fibrosis

Evaluation of aggregate microstructures following natural regeneration in bauxite residue as characterized by synchrotron-based X-ray micro-computed tomography

Bauxite residue often has poor physical conditions which impede plant growth. Native plant encroachment on a bauxite residue disposal area in Central China reveals that natural regeneration may improve its physicochemical properties. Residue samples collected from three different disposal ages were assessed to evaluate residue micromorphology and three-dimensional (3D) aggregate microstructure under natural regeneration. The residue aggregates in different disposal ages were divided in two sections: macro-aggregate (2–1 mm) and micro-aggregate (0.25–0.05 mm). Residue aggregate micromorphology was determined by scanning electron microscope and energy dispersive X-ray spectroscopy, and the residue aggregate microstructure was determined by synchrotron-based X-ray micro-computed tomography (SR-μCT) and image analysis techniques. Natural regeneration may improve residue aggregate stability and form a stable aggregate structure. Calcium content increased whilst sodium content decreased significantly on the surface of residue aggregates. Under natural soil-forming processes bauxite residue porosity, specific surface area, average length of paths, and average tortuosity of paths all significantly increased. This demonstrated that natural regeneration may stimulate the formation of stable aggregate structure in residues. Further understanding should focus on particle interaction forces and agglomeration mechanisms with the addition of external ameliorations