“锡”析相关

开发了一套展示电解锡的科普实验装置,该装置互动性强并且操作便捷,涉及科教演示技术领域。通过本实验装置,参与者可以直观看到电解液通电后在阴极快速生长出漂亮的锡晶体,在阳极产生大量气体,以及溶液颜色发生变化,深度体验化学之美、化学之趣。调节直流电源的电压值,可以改变锡晶体析出的速度;电流方向切换开关可以便捷地转换电流方向,LED指示灯显示电流方向,让参与者能轻松体会到电流方向与锡晶体析出方向,电流方向与阳极析出气体及电解液pH变化的关系,便于理解化学科学中的电解原理;锡晶体生长完成后加入AB胶,得到的塑封成品可以作为留念,给参与者留下美好的回忆,达到良好的科普效果。本实验仪器设备简单,成本不高,也可以作为大学普通化学课程中的一个基础实验项目或高中生的探究实验。

Interfacial synergism of hollow mesoporous Pt/WO_(x)/SiO_(2)-TiO_(2)catalysts enable highly selective hydrogenolysis of glycerol to 1,3-propanediol

The selective hydrogenolysis of glycerol exhibits great prospects,while the catalysts with high selectivity and activity are still missing and need to be created urgently.Herein,we report the synthesis of hollow mesoporous Pt/WO_(x)/SiO_(2)-TiO_(2)nanosphere catalysts with bi-functional interfaces synergistically for high efficiency conversion of glycerol to 1,3-propanediol.The hollow mesoporous Pt/WO_(x)/SiO_(2)-TiO_(2)catalysts show a typical brick-concrete liked framework with a high surface area(179.3 m^(2)·g^(-1)),large mesopore size(10.6 nm),uniform particle size(~400 nm),and ultrathin shell thickness(~75 nm).The brick anatase nanocrystals and concrete amorphous SiO_(2)networks can selectively rivet Pt nanoparticles and WO_(x)nanocluster species,respectively,thus constructing two interfaces for effective adsorption,rapidly catalytic dehydration and hydrogenation processes.The hollow mesoporous Pt/WO_(x)/SiO_(2)-TiO_(2)catalysts deliver a high selectivity of 53.8%for 1,3-propanediol(1,3-PDO)at a very high glycerol conversion of 85.0%.As a result,a favorable 1,3-PDO yield of 45.7%can be obtained with excellent stability,which is among the best performances of previously reported catalysts.This work paves a new way to synthesize catalysts with high selectivity,high activity and high stability.

Distribution,characteristics and daily fluctuations of microplastics throughout wastewater treatment plants with mixed domestic-industrial influents in Wuxi City,China

In wastewater treatment plants(WWTPs),microplastics(MPs)are complex,especially with mixed domestic–industrial influents.Conventional random grab sampling can roughly depict the distribution and characteristics of MPs but can not accurately reflect their daily fluctuations.In this study,the concentration,shape,polymer type,size,and color of MPs were analyzed by micro-Raman spectroscopy(detection limit of 0.05 mm)throughout treatment stages of three mixed domestic–industrial WWTPs(W1,W2,and W3)in Wuxi City,China,and the daily fluctuations of MPs were also obtained by dense grab sampling within 24 h.For influent samples,the average MP concentration of 392.2 items/L in W1 with 10%industrial wastewater was much higher than those in W2(71.2 items/L with 10%industrial wastewater)and W3(38.3 items/L with 60%industrial wastewater).White polyethylene granules with a diameter less than 0.5 mm from plastic manufacturing were the most dominant MPs in the influent of W1,proving the key role of industrial sources in MPs pollution.In addition,the daily dense sampling results showed that MP concentration in W1 influent fluctuated widely between 29.1 items/L and 4617.6 items/L within a day.Finally,few MPs(less than 4.0 items/L)in these WWTPs effluents were attributed to the effective removal of wastewater treatment processes.Thus,further attention should be paid to regulating the primary sources of MPs.

Time of flight improved thermally grown oxide thickness measurement with terahertz spectroscopy

As a nondestructive testing technique,terahertz time-domain spectroscopy technology is commonly used to measure the thickness of ceramic coat in thermal barrier coatings(TBCs).However,the invisibility of ceramic/thermally grown oxide(TGO)reflective wave leads to the measurement failure of natural growth TGO whose thickness is below 10μm in TBCs.To detect and monitor TGO in the emergence stage,a time of flight(TOF)improved TGO thickness measurement method is proposed.A simulative investigation on propagation characteristics of terahertz shows the linear relationship between TGO thickness and phase shift of feature wave.The accurate TOF increment could be acquired from wavelet soft threshold and cross-correlation function with negative effect reduction of environmental noise and system oscillation.Thus,the TGO thickness could be obtained efficiently from the TOF increment of the monitor area with different heating times.The averaged error of 1.61μm in experimental results demonstrates the highly accurate and robust measurement of the proposed method,making it attractive for condition monitoring and life prediction of TBCs.

An investigation on the link between driver demographic characteristics and distracted driving by using the SHRP 2 naturalistic driving data

Purpose–The purpose of this paper is to investigate the influence of driver demographic characteristics on the driving safety involving cell phone usages.Design/methodology/approach–A total of 1,432 crashes and 19,714 baselines were collected for the Strategic Highway Research Program 2 naturalistic driving research.The authors used a case-control approach to estimate the prevalence and the population attributable risk percentage.The mixed logistic regression model is used to evaluate the correlation between different driver demographic characteristics(age,driving experience or their combination)and the crash risk regarding cell phone engagements,as well as the correlation among the likelihood of the cell phone engagement during the driving,multiple driver demographic characteristics(gender,age and driving experience)and environment conditions.Findings–Senior drivers face an extremely high crash risk when distracted by cell phone during driving,but they are not involved in crashes at a large scale.On the contrary,cell phone usages account for a far larger percentage of total crashes for young drivers.Similarly,experienced drivers and experienced-middle-aged drivers seem less likely to be impacted by the cell phone while driving,and cell phone engagements are attributed to a lower percentage of total crashes for them.Furthermore,experienced,senior or male drivers are less likely to engage in cell phone-related secondary tasks while driving.Originality/value–The results provide support to guide countermeasures and vehicle design.