云数据库中基于极大熵差分进化的负载评估算法

由于分布式关系型数据库基于两阶段提交协议的设计方式,使得系统如出现单节点瓶颈问题,数据库事务将全部回滚,从而造成巨大的系统开销,影响数据库在大数据环境下的应用。针对这一现状,提出一种基于极大熵差分进化的负载评估算法,利用评价函数法,将多目标优化问题转化为不可微的单目标优化问题,再利用极大熵函数,将不可微优化问题转化为一个带有参数的无约束优化问题,最后用差分进化算法对其进行求解,找出节点资源最优集,从而为过载节点的数据迁移提供了理论依据,也进一步实现了对云数据库的设计。实验结果表明,该算法能够提高系统的整体性能,有效避免单节点瓶颈问题。     

Toxicological effects and risk assessment of lanthanum ions on leaves of Vicia faba L.seedlings

Vicia faba L.seedlings were hydroponically cultivated in 0-12 mg/L of extraneous lanthanum(La) for 15 d to investigate ecotoxicological effects and risk assessment of rare earth elements(REEs).The results showed that reactive oxygen species(ROS) production suchas superoxide radical(O2.-) and hydrogen peroxide(H2O2) were overproduced at higher concentrations of La,resulting in oxidatively modified proteins and shoot growth retardation.While,superoxide dismutase(SOD),catalase(CAT),ascorbate peroxidase(APX) and guaiacolperoxidase(GPX) isoenzymes were elevated to some extent to eliminate excess of ROS.HSP70 production and endopeptidase isoenzymeswere also enhanced,which were involved in repairing or degradation of the oxidatively modified proteins due to La.Thus,the antioxidantisoenzymes,endoprotease isoenzymes and HSP70 worked cooperatively to alleviate the La-induced oxidative damage.The significant enhancement of CAT and APX isoenzymes and HSP70 could also be used as early bioindicators of La-polluted solution.The threshold doserange was firstly delimited as 1-2 mg/L of extraneous La,corresponding to 7.34-9.37 μg/g dry weight in the leaves.These results would behelpful to further understand the toxicological effects and possible mechanisms of REE(s) on crop seedlings.     

超高效液相色谱法检测食用植物油中的苯并(a)芘

建立了超高效液相色谱法测定食用植物油中苯并(a)芘的方法.实验采用固相萃取方法提取样品中的苯并(a)芘,用ACQUITY UPLC(R) BEH C(18)色谱柱(100 mm×2.1 mm,1.7μm),以0.02mol/L的乙腈-水(体积比为80:20)为流动相,流速0.3 mL/min,柱温25℃,二极管阵列检测器在波长296 nm进行检测.测定在3 min内完成,样品分析的相对标准偏差为2.65%,加标回收率在96.6%-104.8%之间.     

两种不同优化方法对静电液滴法制备单分散海藻酸钙微球工艺的比较

采用星点设计-效应面法和正交设计两种实验设计方法优化高压静电液滴发生技术制备海藻酸钙微球的工艺,以电压、浓度、距离为自变量,海藻酸钙微球的平均粒径为因变量,对自变量各水平进行多元线性回归和二项式拟合,选取最佳工艺条件制备微球。通过两种方法的对比研究,星点-效应面法在优化静电液滴法制备海藻酸钙微球工艺上的可预测性更强,结果更精确,信息获取量更多,效果更佳。     

LEDs技术在果蔬杀菌保鲜领域应用研究进展

水果和蔬菜是人类饮食的重要组成部分,可为人体提供多种营养物质。然而,果蔬在采收、加工、贮藏等环节极易污染微生物,造成品质劣变,甚至引发食源性疾病。作为一种非热加工技术,发光二极管(LEDs)技术具有绿色环保、节能、寿命长等优点,在农业和食品领域具有广阔应用前景。综述LEDs技术在果蔬杀菌中应用,探讨LEDs技术的杀菌机理及影响因素,概括LEDs技术对果蔬主要品质的影响,并对该技术的发展趋势进行讨论分析。     

多点微差起爆在沟槽硐室爆破中的应用

介绍了利用药包群换多点微差起爆，采用硐室爆破开挖沟的方法，这对如何利用药包群的合理布置，装药量和起爆顺序及时差来提高硐室爆破的抛掷率，改善破碎效果及减少爆破危害具有指导作用。     

Cr3+‐activated Li5Zn8Al5Ge9O36: A near‐infrared long‐afterglow phosphor

Near‐infrared long‐afterglow (LAG) materials have attracted considerable attention owing to their high potential for in vivo imaging applications. Here, we present a series of near‐infrared LAG phosphors Li₅Zn₈Al_5?xGe₉O₃₆:xCr³⁺ (LZAG:Cr³⁺), which were synthesized using a solid‐state reaction method. The pure LZAG host exhibits blue photoluminescence and LAG emission. We investigated the effect of the zinc vacancy contents on the photoluminescence and LAG performance by adjusting the zinc content and introducing Ga³⁺ ions to substitute the Zn²⁺ sites in LZAG host. When Cr³⁺ ions were introduced into the LZAG host, LZAG:Cr³⁺ produced a strong, broad blue emission band centered at 456 nm and a near‐infrared emission band at 700 nm caused by the ²E → ⁴A₂ transition of Cr³⁺. The energy transfer processes from the LZAG host to Cr³⁺ were identified in the photoluminescence and LAG process. After irradiation at 258 nm for 10 minutes, the LAG emission of LZAG:0.008Cr³⁺ can last nearly 2.5 hours. Moreover, the LAG intensity and duration of LZAG: 0.008Cr³⁺ were significantly improved by introducing a small dose of Ga³⁺ ions. Finally, the traps and mechanism of LAG in LZAG, LZAG:Ga³⁺, and LZAG:Cr³⁺ were discussed in detail.     

火情自动视觉检测系统的设计

针对现有智能楼宇火情自动视觉检测系统中对火情严重程度的判断功能不足,无法提供多样性信息的问题,设计并实现了智能火情多状态视觉检测系统,监控系统设计了底层控制站CCD视觉信息采集模块和DP总线信息传递模块,增加了智能火情多状态视觉检测系统的功能,利用火情检测图像的均值作为初始背景,根据不同火情事件获取背景图像进行实时更新,依据DSP处理器得到二值图上目标特征设定不同阀值,判断发生了哪类火情,对火情不同事件识别率达到了95%,适用于新一代的智能楼宇监控系统应用。     

High-Voltage Aqueous Na-Ion Battery Enabled by Inert-Cation-Assisted Water-in-Salt Electrolyte

Water-in-salt (WiS) electrolytes provide a new pathway to widen the electrochemical window of aqueous electrolytes. However, their formulation strongly depends on the solubility of the chosen salts, imposing a stringent restriction on the number of possible WiS systems. This issue becomes more severe for aqueous Na-ion batteries (ANIBs) owing to the relatively lower solubility of sodium salts compared to its alkaline cousins (Li, K, and Cs). A new class of the inert-cation-assisted WiS (IC-WiS) electrolytes containing the tetraethylammonium (TEA⁺) inert cation is reported. The Na IC-WiS electrolyte at a superhigh concentration of 31 mol kg^–1 exhibits a wide electrochemical window of 3.3 V, suppresses transition metal dissolution from the cathode, and ensures singular intercalation of Na into both cathode and anode electrodes during cycling, which is often problematic in mixed alkali cation systems such as K–Na and Li–Na. Owing to these unique advantages of the IC-WiS electrolyte, the NaTiOPO₄ anode and Prussian blue analog Na_1.88Mn[Fe(CN)₆]_0.97·1.35H₂O cathode can be coupled to construct a full ANIB, delivering an average voltage of 1.74 V and a high energy density of 71 Wh kg⁻¹ with a capacity retention of 90% after 200 cycles at 0.25C and of 76% over 800 cycles at 1C.     

TiB2-SiC粉末喷雾造粒及其等离子喷涂沉积机理研究

利用喷雾干燥对TiB_2-SiC复合粉末进行造粒,研究了浆料固含量、粘结剂含量及SiC含量对喷雾干燥粉体颗粒形貌等的影响。采用大气等离子喷涂技术,以抛光的石墨为基体,在不同预热温度和不同喷距下对TiB_2-SiC粉末进行粒子收集,研究不同工艺参数对TiB_2-SiC粒子铺展形貌的影响,并制备了TiB_2-SiC涂层。结果表明:当浆料固含量为50%,粘结剂含量为5%,SiC含量为10%时,喷雾造粒获得球形度高、流动性好的TiB_2-SiC粉末;随着基体预热温度的升高,喷距的增大,扁平粒子的溅射逐渐减弱,形成规则的圆盘状粒子;在等离子焰流作用下,TiB_2-SiC粒子熔化加速并与基体发生碰撞,熔融粒子扁平化,急速冷却凝固,不断堆叠、搭接为宏观涂层。