脉冲电源电解处理含氰含银电镀废水

利用脉冲电源从含氰含银电镀废水中回收银和去除氰,对比了脉冲电源与直流电源对含氰镀银废水的处理效果,系统研究了脉冲电源的电解电压、占空比和脉冲频率等参数对电能消耗、银回收率和除氰率的影响。结果表明,脉冲电源较直流电源能更加有效降低阳极的超电位,减少电极的极化,从而降低槽电压,进而有效地降低电能消耗。脉冲电源的优化参数是:脉冲电压2.0V,脉冲频率1200Hz,占空比50%。在循环流速100ml.min-1,pH值10～11,曝气速率1.0L·min-1的实验条件下,通入电解电压2.0V、脉冲频率1200Hz以及占空比50%的脉冲电源,电解2.0h后,银回收率高达99%,除氰率达到86%

IrO_2-RuO_2/Ti电极处理含氰含银电镀废水

采用热氧化分解法制备了IrO2-RuO2/Ti电极,用X射线衍射(XRD)和扫描电镜(SEM)以及X射线能谱仪(EDS)对其进行表征,并考察其对脉冲电解含氰含银电镀废水中银离子的还原和氰化物分解的影响。结果表明:用热氧化分解法制备的IrO2-RuO2/Ti电极表面具有"泥裂"现象,其主要成分为IrO2,RuO2和TiO2。以IrO2-RuO2/Ti为阳极,不锈钢圆筒为阴极,在脉冲电压0.5 V,脉冲频率1 200 Hz,占空比50%,曝气量1.0 L/min,电解液循环流速100 mL/min和pH值10~11的条件下,常温电解4.0 h,发现IrO2-RuO2/Ti电极性能优于石墨电极、PbO2/Ti电极和不锈钢电极,在其作用下,废水中银离子的回收率达到99.66%,氰分解率达到91.63%

Combustion characteristics of premixed C1—C4 alkane jet flames between two parallel walls

The combustion characteristics of premixed C1—C4 alkane jet flames were studied experimentally with a slit burner between two parallel walls. The effects of wall temperature, the distance between two walls, equivalence ratio and fuel type on flame patter

平板狭缝间C1～C4烷烃/空气预混射流火焰的燃烧特性

对平行平板狭缝间C_1～C_4烷烃预混射流火焰进行了实验研究,考察了壁面温度、狭缝间距、当量比、燃料种类等对火焰形态和稳定性的影响,并利用高速相机获得了狭缝间的火焰图像。结果表明,随着狭缝间距的减小,火焰经历了稳定、脉动和熄火3个阶段。其中,火焰脉动发生在大于熄火间距的狭小范围内,其脉动频率随着壁面温度的升高而增加。对同一种燃料,当预混气当量比和壁面温度保持恒定时,火焰的脉动频率在脉动发生的区域内保持不变。对比C_1～C_4烷烃预混火焰的脉动频率及脉动火焰持续距离范围,发现甲烷预混火焰的均最小,而其他3种燃料则比较接近

平板狭缝间C_1~C_4烷烃/空气预混射流火焰的燃烧特性

对平行平板狭缝间C_1～C_4烷烃预混射流火焰进行了实验研究,考察了壁面温度、狭缝间距、当量比、燃料种类等对火焰形态和稳定性的影响,并利用高速相机获得了狭缝间的火焰图像。结果表明,随着狭缝间距的减小,火焰经历了稳定、脉动和熄火3个阶段。其中,火焰脉动发生在大于熄火间距的狭小范围内,其脉动频率随着壁面温度的升高而增加。对同一种燃料,当预混气当量比和壁面温度保持恒定时,火焰的脉动频率在脉动发生的区域内保持不变。对比C_1～C_4烷烃预混火焰的脉动频率及脉动火焰持续距离范围,发现甲烷预混火焰的均最小,而其他3种燃料则比较接近

Si, Ag, F离子共修饰HA纳米生物薄膜的制备与表征

采用单电流阶跃电化学沉积技术，在商业纯钛(CP-Ti)表面构建硅、银、氟离子共修饰羟基磷灰石(Si-Ag-F-HA)纳米复合薄膜。Ag+的持续释放可以提供有效的抗菌性，Si4+作为生物活性元素可以有效地抵消Ag+的潜在细胞毒性。采用电感耦合等离子体质谱法(ICP-MS)测定涂层中硅和银元素的释放规律。采用傅里叶变换红外光谱(FTIR)、扫描电子显微镜(SEM)、能量弥散X射线谱(EDS)、X-射线衍射(XRD)等技术对得到的材料进行了表征。结果表明：Si，Ag和F三种元素均匀地掺杂到了HA的晶体结构中。Si-Ag-F-HA为纳米级的针状晶体结构，薄膜整体致密且均匀。Si-Ag-F-HA纳米生物薄膜可以在一周内很好地诱导类骨磷灰石的形成，具有优异的生物活性。塔菲尔曲线测试结果证实涂层的耐SBF腐蚀性较好。ICP-MS测试结果表明Si-Ag-F-HA纳米生物薄膜可以提供持续的Si和Ag离子释放。FTIR 和ICP-MS等光谱技术为开发新型抗菌硬组织修复材料提供了高效快速的检测手段。 In this study, a novel silicon, silver, fluorine co-modified hydroxyapatite (Si-Ag-F-HA) nano-biofilms was deposited on CP-Ti through electrodeposition. Ag was incorporated into HA coating to improve the antimicrobial properties. Si was added as a second binary element to offset the potential cytotoxicity of Ag. The as-prepared coatings were examined by scanning electron microscope (SEM), energy-dispersive X-ray spectroscopy (EDS), Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) tests. Results highlight that F-, Si4+ and Ag+ could be evenly incorporated into the Si-Ag-F-HA coating. The results indicate that the Si-Ag-F-HA coatings take the morphology of nanoscale- villous-like, the composite coating becomes more compact. The composite coatings were found to be bioactive, based on the promotion of additional apatite onto the Si-Ag-F-HA coating surface from SBF. Potentiodynamic polarisation tests revealed that the corrosion resistance increased after Si-Ag-F-HA coating. The release of Si and Ag ions from Si-Ag-F-HA coatings shows sustained release kinetics without burst release, which reached a near steady state afterwards, thereby revealing long-term sustainable release. FTIR and ICP-MS provide a rapid and effective method for the development of new antibacterial hard tissue repair materials. © 2018, Peking University Press. All right reserved

Prediction of Energy Resolution in the JUNO Experiment

International audienceThis paper presents the energy resolution study in the JUNO experiment, incorporating the latest knowledge acquired during the detector construction phase. The determination of neutrino mass ordering in JUNO requires an exceptional energy resolution better than 3% at 1 MeV. To achieve this ambitious goal, significant efforts have been undertaken in the design and production of the key components of the JUNO detector. Various factors affecting the detection of inverse beta decay signals have an impact on the energy resolution, extending beyond the statistical fluctuations of the detected number of photons, such as the properties of liquid scintillator, performance of photomultiplier tubes, and the energy reconstruction algorithm. To account for these effects, a full JUNO simulation and reconstruction approach is employed. This enables the modeling of all relevant effects and the evaluation of associated inputs to accurately estimate the energy resolution. The study reveals an energy resolution of 2.95% at 1 MeV. Furthermore, the study assesses the contribution of major effects to the overall energy resolution budget. This analysis serves as a reference for interpreting future measurements of energy resolution during JUNO data taking. Moreover, it provides a guideline in comprehending the energy resolution characteristics of liquid scintillator-based detectors