Acetic acid additive in NaNO_(3)aqueous electrolyte for long-lifespan Mg-air batteries

Mg-air batteries have attracted tremendous attention as a potential next-generation power source for portable electronics and e-transportation due to their remarkable high theoretical volumetric energy density,environmental sustainability,and cost-effectiveness.However,the fast hydrogen evolution reaction(HER)in NaCl-based aqueous electrolytes impairs the performance of Mg-air batteries and leads to poor specific capacity,low energy density,and low utilization.Thus,the conventionally used NaCl solute was proposed to be replaced by NaNO_(3)and acetic acid additive as a corrosion inhibitor,therefore an electrolyte engineering for long-life time Mg-air batteries is reported.The resulting Mg-air batteries based on this optimized electrolyte demonstrate an improved discharge voltage reaching~1.8 V for initial 5 h at a current density of 0.5 mA/cm^(2) and significantly prolonged cells'operational lifetime to over 360 h,in contrast to only~17 h observed in NaCl electrolyte.X-ray photoelectron spectroscopy and time-of-flight secondary ion mass spectrometry were employed to analyse the composition of surface film and scanning electron microscopy combined with transmission electron microscopy to clarify the morphology changes of the surface layer as a function of acetic acid addition.The thorough studies of chemical composition and morphology of corrosion products have allowed us to elucidate the working mechanism of Mg anode in this optimized electrolyte for Mg-air batteries.

Mg anode interface engineering in KNO_(3) electrolyte with sodium 5-sulfosalicylate as an additive for enhanced performance of Mg-air batteries

The Mg-air batteries face limitations with pronounced hydrogen evolution and low anodic utilization efficiency from Mg anodes in conventional NaCl electrolytes.The corrosion performance,surface composition,and discharge properties of commercial purity Mg anodes were thoroughly investigated in KNO_(3)electrolytes with and without sodium 5-sulfosalicylate and compared to NaCl electrolyte.The addition of sodium 5-sulfosalicylate to KNO_(3)-based electrolyte results in efficient inhibition of H_(2)evolution,consequently enhancing anodic utilization efficiency to 84%and specific capacity to 1844 mAh/g,compared to NaCl(24%and 534 mAh/g,respectively)under discharge condition of 10 mA/cm^(2)in half cell.Furthermore,the chelating ability of sodium 5-sulfosalicylate can significantly improve the Mg surface dissolution kinetics and discharge product deposition rate at the Mg anode/electrolyte interface,yielding formation of a thinner discharge layer as confirmed by time-of-flight secondary ion mass spectrometry.The discharge voltage is increased to 1.60 V,compared to 1.35 V in KNO_(3)at 0.5 mA/cm^(2)in full cell.However,higher concentration of sodium 5-sulfosalicylate can accelerate Mg anode dissolution,impeding the improvement of anodic utilization efficiency,specific capacity,and energy density.Hence,determining optimal additive concentration and current density is crucial for enhancing the discharge properties of Mg-air batteries and mitigating excessive Mg dissolution in chloride-free electrolytes.

地方高校选修课程考核模式的改革与探索——以汉江师范学院为例

课程考核是课程教学中提高教学质量和评价人才培养质量的重要环节及有效手段。然而,地方高校汉江师范学院选修课程仍然存在考核方式单一、学生积极性差、创新性不足的问题。本文对选修课程考核模式进行了改革与探索,以表面活性剂化学课程为例,从教师评价、学生互评、学生贡献等三个角度出发,以科学成才观念为核心,设计并实践了教师评价(代号“T”)、组组互评(代号“G”)、个人贡献比(代号“I”)的“TGI”考核模式,打破传统的考核方式,提高学生积极性与主动性,激发学生的创新性,活化学生创新思维,培养学生的综合能力。“TGI”考核模式对提高课程教学质量具有重要的意义,对其他选修课程考核评价具有一定的借鉴作用。

无机及分析化学实验“三维”教学模式的设计与实践

无机及分析化学实验是汉江师范学院生物科学专业在大一开设的首门必修实验课程,其教学质量对后续专业课程的学习、学生学术研究能力和创新性思维的培养等具有重要意义。然而,汉江师范学院无机及分析化学实验教学过程中存在理论课程与实验课程教学进度不匹配、学生课前预习不充分以及课程期末考核方式单一等问题。笔者通过课件推送、问题收集、能力提升的“三维”教学模式,突出学生的主体地位,将实验课程的考核机制落实到课程学习的各个环节,旨在提高学生的学习动力和激发学生的求知欲。该“三维”教学模式的实施对提高无机及分析化学实验课程的教学质量具有重要意义。

Characteristics Analysis on Short-Time Heavy Rainfall during the Flood Season in Shanxi Province, China

In order to provide a reference for the correct forecasting of short-term heavy rainfall and better disaster prevention and mitigation services in Shanxi Province, China, it is very important to carry out systematic research on short-term heavy precipitation events in Shanxi Province. Based on hourly precipitation data during the flood season (May to September) from 109 meteorological stations in Shanxi, China in 1980-2015, the temporal and spatial variation characteristics of short-time heavy rainfall during the flood season are analyzed by using wavelet analysis and Mann-Kendall test. The results show that the short-time heavy rainfall in the flood season in Shanxi Province is mainly at the grade of 20 - 30 mm/h, with an average of 97 stations having short-time heavy rainfall each year, accounting for 89% of the total stations. The short-time heavy rainfall mainly concentrated in July and August, and the maximal rain intensity in history appeared at 23 - 24 on June 17, 1991 in Yongji, Shanxi is 91.7 mm/h. During the flood season, the short-time heavy rainfalls always occur at 16 - 18 pm, and have slightly different concentrated time in different months. The main peaks of June, July and August are at 16, 17 and 18 respectively, postponed for one hour. Short-time heavy rainfall overall has the distribution that the south is more than the north and the east less than the west in Shanxi area. In the last 36 years, short-time heavy rainfall has a slight increasing trend in Shanxi, but not significant. There is a clear 4-year period of oscillation and inter-decadal variation. It has a good correlation between the total precipitation and times of short-time heavy rainfall during the flood season.

梯度磁场在生物大分子研究中的应用

磁场作为一种物理环境,广泛应用于各行各业.随着磁体技术的飞速发展,磁场在科学研究与实践应用中的重要性日趋凸显.在生物大分子研究方向,磁场也发挥了重要的作用.其中,梯度磁场作为磁场的一种,由于其提供的资源除磁场外,还有磁场梯度,使其具备除常规磁场效应(择优取向、晶体质量改善等)外的其他应用价值(如溶液的对流控制、晶体质量改善、分离纯化等),因此备受关注.梯度磁场环境下涉及生物大分子的研究,主要集中在生物大分子的结晶、分离与纯化,以及自组装等方向.充分利用梯度磁场,可以实现高质量的生物大分子晶体生长、高效低成本的生物大分子分离与纯化等重要应用.因此,梯度磁场在生物大分子结构解析技术、生物药物制备技术等方向具有十分重要的价值.本文将从梯度磁场物理环境对生物大分子溶液体系的基础性影响角度出发,回顾并讨论梯度磁场在生物大分子研究中的应用,并对该领域的发展前景进行了预期.

蛋白质自组装条件筛选形成的透明液滴中存在的自组装现象

微-纳尺度的蛋白质自组装体具有形貌多样性与良好的生物相容性,因而成为蛋白质自组装领域的研究热点。以蛋白质结晶条件的筛选手段高通量筛选不同类型蛋白质于不同尺度、不同形貌的自组装过程,是一种新兴的研究方法,具有重要研究意义。利用该方法进行蛋白质自组装条件筛选时,常会形成一些表观透明的液滴,其中是否有自组装现象的发生尚不明确。文中以β-乳球蛋白与蛋白质结晶试剂盒Index^(TM) C10相互作用为例进行探索,实验结果表明透明液滴中存在微-纳尺度的蛋白质自组装体。进一步通过扫描电镜观察不同初始浓度β-乳球蛋白与Index^(TM) C10混合形成的透明液滴中微-纳自组装体的形貌有所差别;通过激光共聚焦显微镜连续拍摄添加荧光标签的β-乳球蛋白形成自组装体的过程,可实时观察到液液相分离现象及最终形成的自组装体的形貌;通过原位X-射线衍射手段,可观察到自组装体内部结构随时间推移逐渐有序化的过程。以上研究表明,在以结晶条件筛选手段为基础的蛋白质自组装条件筛选实验中,透明液滴内的自组装现象具有深入探索的必要和价值。

Development of source profiles and their application in source apportionment of PM2.5 in Xiamen, China

Ambient PM2.5 samples were collected at four sites in Xiamen, including Gulangyu （GLY）. Hongwen （HW）, Huli （HL） and Jimei （JM） during January, April, July and October 2013. Local source samples were obtained from coal burning power plants, industries, motor vehicles, biomass burning, fugitive dust, and sea salt for the source apportionment studies. The highest value of PM2.5 mass concentration and species related to human activities （SO42- , NO3 , Pb, Ni, V, Cu, Cd, organic carbon （OC） andelemental carbon （EC）） were found in the ambient-samples from HL, and t-he highest and lowest loadings of PM2.5 and its components occurred in winter and summer, respectively. The reconstructed mass balance indicated that ambient PM2.5 consisted of 24% OM （organic matter）, 23% sulfate, 14% nitrate, 9% ammonium, 9% geological material, 6% sea salt, 5% EC and 10% others. For the source profiles, the dominant components were OC for coal burning, motor vehicle, biomass burning and sea salt; SO42 for industry; and crustal elements for fugitive dust. Source contributions were calculatedusing a chemical mass＇balance （CMB） model basedon ambient PM2.5 concentrations and the source profiles. GLY was characterized by high contributions from secondary sulfate and cooking, while HL and JM were most strongly affected by motor vehicle emissions, and biomass burning and fugitivedust, respectively. The CMB results-indicated that PM2.5 from Xiamen is composed of 27.4% secondary inorganic components, 20.8% motor vehicle emissions, 11.7% fugitive dust, 9.9% sea salt, 9.3% coal burning, 5.0% biomass burning, 3.1% industry and 6.8% others.

Factors responsible for unanticipated hypertension during emergence from general anesthesia

To the Editor:Unanticipated hypertension during emergence refers to acutely elevated blood pressure following general anesthesia in individuals with normal preoperative baseline blood pressure.[1]Due to their normal preoperative blood pressure,inadequate attention was paid to this population.Acute postoperative hypertension,if left untreated,has been linked to serious postoperative consequences such as vascular anastomosis rupture,and cardiovascular and cerebrovascular accidents,affecting the outcome of critically ill and surgical patients.[2]Few studies have revealed the risk factors for unanticipated hypertension after general anesthesia.We performed this retrospective study to identify the factors responsible for unexpected hypertension in adult surgical patients resuscitated from anesthesia based on real-world data from an anesthesia center in eastern China,to provide evidence for perioperative management within this surgical patient population.