Structural chemistry of M2Si5N8:Eu2+ (M = Ca, Sr, Ba) phosphor via structural refinement

Structural refinement using X-ray powder diffraction data and geometry energy calculations using quantum mechanics were used to investigate the preferential substitution sites and the amount of Eu2+ ions in the host lattice of alkaline earth elements co-doped M2Si5N8:Eu2+ (M = Ca, Sr, and Ba), which is a red color-emitting nitride phosphor prepared via a carbothermal reaction method. Of the possible preferential sites, the preferential site proposed by the structural refinement results, in which the Eu2+ ions might preferentially occupy nine coordinated sites with nitrogen in M2Si5N8:Eu2+, was confirmed via geometry energy calculations using a first-principle based on the density-functional theory. The final converged weighted R factor (R(wp)) and the goodness-of-fit indicator [S(= R(wp)/R(e))] were 9.51% and 1.77, respectively. Each occupancy of Eu2+ ions for the two non-equivalent M sites, M(1) and M(2), was 0.10(2) and 0.04(2), respectively. The final refined model described the crystal structure in a space group Pmn2, (No. 31) with Z = 2, a = 5.7424(1) angstroms, b = 6.8837(1) angstroms, c = 9.3586(1) angstroms, and alpha(= beta= gamma)= 90 degrees.     

Ratcheting behaviour and mean stress considerations in uniaxial low-cycle fatigue of Inconel 718 at 649 °C

The ratcheting behaviour of Inconel 718 was investigated at 649 °C under uniaxial cyclic loading. Stress-control tests have been conducted at various combinations of stress amplitude and mean stress. The ratcheting strain at failure increases with increasing mean stress for a given stress amplitude and with decreasing stress amplitude for a given mean stress. Fatigue lives were correlated using three mean stress models: the Goodman equation, the Smith–Watson–Topper (SWT) parameter and the Walker parameter. It has been shown that the Goodman equation and the SWT parameter do not correlate life data, while the Walker parameter yields acceptable correlation. The SWT parameter was modified to incorporate the ratcheting effect. The new parameter is found to yield correlation similar to that of the Walker parameter.     

一种改进的液晶面板制造执行系统

随着中小尺寸液晶面板的多样性发展,企业实施一种高稳定性的制造执行系统是一种必然趋势。对物料搬送采用无线射频技术实现自动化搬送,减少了生产服务器对生产信息和搬送命令的控制。为了避免文件服务器在生产过程中影响,采用检查结果和检查文件两个路径上报采集方案,提高了检查数据业务集成化。针对报表系统采用专门工程数据库管理报表数据,大大提高了用户的响应速度,也减少了生产数据库服务器的负荷。该系统在实际液晶面板制造过程中表明,生产运转率和系统性能都得到了明显改善。     

Mn valence state and electrode performance of perovskite-type cathode La0·8Sr0·2Mn1 − x Cu x O3 − δ (x = 0, 0·2) for intermediate-temperature solid oxide fuel cells

Cu-free and Cu-doped LSM system, La_0·8Sr_0·2Mn_1???x Cu _x O_3???δ (x?=?0, 0·2), with perovskite structure were prepared using an EDTA combined citrate process and the effects of Cu ion at B-site were investigated. Electrical conductivity and polarization resistance of the Cu-doped LSM were 210 S·cm^???1 at 750 °C, and 2·54 Ω · cm² at 800 °C, respectively which were better than those of the Cu-free LSM. This indicated that the electrode performance of LSM was improved by the addition of Cu. The oxidation state of Mn ions increased with addition of Cu. The increase in the oxidation state of Mn ions was due to the formation of Mn^4?+? ions and oxygen vacancies. The addition of Cu ions to LSM systems could lead to enhanced electrode performance for oxygen reduction reactions originating from the change in valence of Mn ions.     

车用仪表背光灯的LED线性恒流驱动电路设计

阐述了可用于车用仪表背光灯的高精度LED线性恒流驱动芯片设计,重点讨论在设计并联方式LED线性恒流驱动电路时如何消除连线分布电阻的影响,并推出一种新颖的可消除连线分布电阻影响的电路,最终通过电路模拟测试加以验证.研究结果表明,在设计高精度、高稳定性、大电流、并联方式LED线性恒流驱动电路时,消除连线分布电阻影响很有必要...     

Effects of Phosphates on Firming Rate of Cooked Rice

The effects of phosphates having different contents of P₂O₅ on the rate of firming of cooked rice during storage at room temperature were investigated. Phosphates showed a definite effect in retarding the rate of firming of cooked rice. The cooked rice containing phosphates having 60 and 67% P₂O₅ contents were firmed slower by 1.4 and 1.6 times, respectively, than control. Phosphates having more than 68% P₂O₅ content showed similar results to that of 67% P₂O₅ phosphate, implying that P₂O₅ content may be an important effective factor in retarding the firming of cooked rice.     

Apple Cultivar Variations in Response to Heat Treatment and Minimal Processing

Eleven apple cultivars were subjected to heat treatments at various times and temperatures. Susceptibility to browning during heat treatment and after heat treatment was evaluated. Changes in firmness, respiration rate, soluble solids and acidity of slices prepared with heat treated apples were measured. Incidence of browning was dependent upon cultivar and heating temperature; Liberty, Monroe, RI Greening and Rome were very susceptive, while McIntosh, NY 674 and Empire were less susceptive. Golden Delicious and Delicious showed relative strong tolerance to heat. Apples that received heat treatment at 45°C produced slices with less browning and firmer texture compared to non-treated apples. The positive effect of heat treatment might help produce high quality minimum processed fruits.     

CHANGES IN RHEOLOGICAL PROPERTIES OF HYDROXYPROPYL POTATO STARCH PASTES DURING FREEZE-THAW TREATMENTS II. EFFECT OF MOLAR SUBSTITUTION AND CROSS-LINKING

The effects of molar substitution (M.S.) and cross-linking on the freeze-thaw stability of hydroxypropyl potato starch pastes were studied by following the changes in the rheological behaviour during heat treatment of the thawed starch pastes, and by determination of syneresis. In addition, differential scanning calorimetry (DSC) was used to investigate the thermal transition properties of the starch pastes that exhibited syneresis. With increasing M.S., the changes in both complex modulus (G*) and phase angle (δ) indicative of destabilization, and starch paste syneresis were delayed with regard to the number of freeze-thaw cycles. When a starch paste showed a peak in G*, related to syneresis, it also showed a thermal transition peak in the DSC measurements. The enthalpy value decreased with increasing M.S., and it appeared to be related to the extent of syneresis and the magnitude of the peak in G*. Comparison of the rheological behaviour of hydroxypropyl potato starch pastes and hydroxypropyl and cross-linked potato starch pastes, suggested that the former were gradually transformed into coarsely aggregated structures while the latter became diluted starch dispersions, due to shrinkage of swollen starch granules and their disruption.     

难处理金矿浸出预处理过程的FeS2-FeAsS-H2O系电位-pH图

难处理金矿中,金为微细浸染型嵌布在黄铁矿和毒砂的晶格中而不能被充分浸出.本文通过热力学计算绘制了298.15KFeS2-FeAsS-H2O系的电位-pH图,由图可知黄铁矿和毒砂均可以被O2等氧化剂分解.FeAsS的稳定区完全包含在FeS2的稳定区范围内,说明在酸性条件下毒砂比黄铁矿的稳定性差,更容易被分解.当电位及酸度...