补钙剂中钙含量测定实验的课程思政设计

高锰酸钾法测定补钙剂中钙的含量是一个经典的分析化学实验。本案例由“中国人普遍缺钙”这一调查结果作为切入点,引导学生利用所学理论知识测定市售某补钙剂产品中钙的含量,并开展分组实验重点探究草酸钙沉淀的生成条件及洗涤方法对补钙剂中钙含量测定结果的影响。将“思政寓课程,课程融思政”的教学理念贯穿于实验教学全过程中,能够提高学生学以致用的能力,切实培养他们的安全意识、环保意识、科学素养、团队意识及创新能力,同时强化其“每个人是自己健康第一责任人”的意识。

“互联网+”背景下基础化学原理实验在线学习与考试系统的开发与实践

在移动互联网的飞速发展与智能手机等移动终端日趋普及的情况下,设计开发了基于移动端的基础化学原理实验在线学习与考试系统。该系统包括化学实验室安全教育与考试、实验基础理论学习、试题库资源、移动端在线考试、成绩管理和统计分析等五大功能。该系统的开发建设顺应了“互联网+教育”的发展趋势,有利于学生自主学习,节约考试资源。

离子选择性电极法测定茶叶及茶水中的氟含量

将经典基础化学实验“离子选择性电极法测定水中微量的氟”实验改进为“离子选择性电极法测定茶叶及茶水中的氟含量”。实验内容由自来水中氟含量测定,拓展到茶叶及茶水氟含量、茶叶氟浸出率的测定;并增加了茶水比、冲泡温度、冲泡时间、冲泡次数、茶叶粒度对茶叶氟浸出率的影响等研究性内容;五大代表性茶样氟含量的测定结果表明,饮用黑茶有氟摄入过量的风险;此外,在离子选择性电极法测氟的应用领域及微量氟的其他检测方法等方面将该实验进一步拓展和延伸。研究性内容的引入及分组实验更有利于培养学生的科研思维和团结协作精神;探索性且具挑战力的实验内容,提高了学生的创新能力及解决实际问题的能力;茶与健康通识内容的渗透,贴近生活,增强了学生的健康意识。本实验内容丰富,趣味性强,易于操作及推广,适合在本科低年级学生中开设。

基于“互联网+”背景的仪器分析类课程MTSAE教学模式构建

在互联网+和双一流学科建设国际化背景下,针对培养具有工程实践能力、团队合作精神和国际视野人才的目标,以提升学生自主创新水平和综合素质为导向,对本科生和研究生仪器分析类课程进行了改革。构建了与国际接轨的MTSAE教学模式,即通过采用网络教学(M)、团队协作(T)、学术研讨(S)、国内外课堂互通(A)和全方位评价(E)等方式来引导学生积极参与到国际化背景的教学活动中,发挥主观能动性,扩充前沿知识储备,增强团队攻关和合作交流能力,有效提升了学生的国际化水平,对于创新型人才的培养起到了积极的推动作用。

Pre-constructed SEI on graphite-based interface enables long cycle stability for dual ion sodium batteries

Lithium batteries have been widely used in all over the world for its high energy density, long-term cycle stability. While the resources of lithium metal and transition metal are limited, which restrict their applications in the grid energy storage. Dual ion sodium batteries(DISBs) possess higher energy density,especially owning high power density for its higher operating voltage(> 4.5 V). Nevertheless, the poor oxidation tolerance of carbonate electrolyte and the co-intercalation of solvents accompanied with anions are main obstacles to make the DISBs commercialization. Herein, a physical barrier(artificial SEI film) is pre-constructed in the Na||graphite batteries to solve these thorny problems. With the CSMG(covered SEI on modified graphite), batteries deliver higher capacity 40 mAh/g even under the current density of 300 mA/g and the capacity retention maintains very well after 100 cycles at a high operating voltage.Moreover, the function mechanism was revealed by in-situ XRD, demonstrating that the pre-constructed SEI can effectively suppress the irreversible phase transition and exfoliation of graphite, resulting from the co-intercalation of anions. Additionally, the work voltage windows of carbonate electrolyte are significantly broadened by establishing electrode/electrolyte interphase. This method opens up an avenue for the practical application of DISBs on the grid energy storage and other fields.

Trace doping realizing superior electrochemical performance in P2-type Na_(0.50)Li_(0.08)Mn_(0.60)Co_(0.16)Ni_(0.16)0_(2)cathode for sodium-ion batteries

P2-type layered oxides are receiving significant interest due to their superior structure and intrinsic performances.There are strenuous attempts to balance the structure stability,phase transition as well as desirable electrochemical performances by inducing anion/cation ions,changing morphology,adjusting valence,etc.In this work,several same-period elements of Sc,Ti,V,Cr,Fe,Cu and Zn are doped into Na_(0.50)Li_(0.08)Mn_(0.60)Co_(0.16)Ni_(0.16)O_(2)cathodes,which are manipulated by ions radii and valence state,further studied by operando X-ray powder diffraction patterns(XRD).As a result,the Cu^(2+)doped cathode performed higher rate capacities(as high as 86 mAh/g even at 10 C)and more stable structures(capacity retention of~89.4%for 100 cycles),which owing to the synergistic effect among the tightened TMO_(2)layer,enlarged d-spacing,reduce O-O electrostatic repulsion,ameliorate lattice distortion as well as mitigate ordering of Na^(+)/vacancy.

Adsorption performance and physicochemical mechanism of MnO_(2)-polyethylenimine-tannic acid composites for the removal of Cu(Ⅱ) and Cr(Ⅵ) from aqueous solution

In this work,an adsorbent,which we call MnPT,was prepared by combining MnO_(2),polyethylenimine and tannic acid,and exhibited efficient performance for Cu(Ⅱ) and Cr(VI) removal from aqueous solution.The oxygen/nitrogen-containing functional groups on the surface of MnPT might increase the enrichment of metal ions by complexation.The maximum adsorption capacities of MnPT for Cu(Ⅱ) and Cr(Ⅵ) were 121.5 and 790.2 mg·g^(-1),respectively.The surface complexation formation model was used to elucidate the physicochemical interplay in the process of Cu(Ⅱ) and Cr(Ⅵ) co-adsorption on MnPT.Electrostatic force,solvation action,adsorbate-adsorbate lateral interaction,and complexation were involved in the spontaneous adsorption process.Physical electrostatic action was dominant in the initial stage,whereas chemical action was the driving force leading to adsorption equilibrium.It should be noted that after adsorption on the surface of MnPT,Cr(Ⅵ) reacted with some reducing functional groups(hydroxylamine-NH_(2))and was converted into Cr(Ⅲ).The adsorption capacity declined by 12% after recycling five times.Understanding the adsorption mechanism might provide a technical basis for the procedural design of heavy metal adsorbents.This MnPT nanocomposite has been proven to be a low-cost,efficient,and promising adsorbent for removing heavy metal ions from wastewater.

Adjunctive sepsis therapy with aminophylline(STAP):a randomized controlled trial

Background:Sepsis is a serious disease caused by infection.Aminophylline has anti-asthma and anti-inflammatory effects.We aimed to explore the safety and effect of aminophylline in sepsis.Methods:We conducted a clinical randomized controlled trial involving 100 patients diagnosed with sepsis within 48 h after intensive care unit(ICU)admission in two sites.All patients were randomized in a 1:1 ratio to receive standard therapy with or without aminophylline.The primary clinical outcome was all-cause mortality at 28 days.Results:From September 27,2018 to February 12,2020,we screened 277 septic patients and eventually enrolled 100 patients,with 50 assigned to the aminophylline group and 50 to the usual-care group.At 28 days,7 of 50 patients(14.0%)in the aminophylline group had died,compared with 16 of 50(32.0%)in the usual-care group(P=0.032).Cox regression showed that the aminophylline group had a lower hazard of death(hazard ratio=0.312,95%confidence interval:0.129–0.753).Compared with the usual-care group,patients in the aminophylline group had a longer survival time(P=0.039 by the log-rank test).The effects of aminophylline on vasopressor dose,oxygenation index,and sequential organ failure assessment score were timedependent with treatment.There were no significant differences in total hospitalization days,ICU hospitalization days,and rates of serious adverse events(all P>0.05).No adverse events were observed in the trial.Conclusions:Aminophylline as an adjunct therapy could significantly reduce the risk of death and prolong the survival time of patients with sepsis.Trial registration:ChiCTR.org.cn,ChiCTR1800019173.

Improving rate performances of Li-rich layered oxide by the co-doping of Sn and K ions

The specific capacities and power performances of conventional cathode materials are still needed to improve in order to meet the demand for electrical vehicles.Li-rich layered oxide delivers a high specific capacity,but poor rate performances.Chemical doping is an effective way to address this challenge due to the expanded crystal lattice.Unlike a single ion substitution in the literature,here Li-rich layered oxides were doped by Sn and K to achieve the favorite rate performance,where Sn and K were assumed to replace transition metal ion and Li ion,respectively.Results indicate the co-doped samples result in an increasing capacity retention by more than 40%from 107.9(contrast sample)to 151.5 mAh g^(-1)(co-doped sample)at 10 C-rate.Electrochemical impedance spectroscopy(EIS)and calculated diffusion coefficient of Li^(+) also confirmed the favorite rate performances for co-doped sample.Combining results of Rietveld structure refinement,we proposed that the reason for rate performances comes from the enlarged crystal lattices,which provides a smooth diffusion tunnel for Lithium ions during the charge/discharge processes.The as-adopted method provides a possibility to achieve the improved rate performances by co-doping big-size ions at the different crystal sites.