Metal-N_(4) model single‐atom catalyst with electroneutral quadri‐pyridine macrocyclic ligand for CO_(2) electroreduction

Metal–N–C single‐atom catalysts,mostly prepared from pyrolysis of metalorganic precursors,are widely used in heterogeneous electrocatalysis.Since metal sites with diverse local structures coexist in this type of material and it is challenging to characterize the local structure,a reliable structure–property relationship is difficult to establish.Conjugated macrocyclic complexes adsorbed on carbon support are well‐defined models to mimic the singleatom catalysts.Metal–N_(4) site with four electroneutral pyridine‐type ligands embedded in a graphene layer is the most commonly proposed structure of the active site of single‐atom catalysts,but its molecular counterpart has not been reported.In this work,we synthesized the conjugated macrocyclic complexes with a metal center(Co,Fe,or Ni)coordinated with four electroneutral pyridinic ligands as model catalysts for CO_(2) electroreduction.For comparison,the complexes with anionic quadri‐pyridine macrocyclic ligand were also prepared.The Co complex with the electroneutral ligand expressed a turnover frequency of CO formation more than an order of magnitude higher than that of the Co complex with the anionic ligand.Constrained ab initio molecular dynamics simulations based on the well‐defined structures of the model catalysts indicate that the Co complex with the electroneutral ligand possesses a stronger ability to mediate electron transfer from carbon to CO_(2).

Cu single-atom electrocatalyst on nitrogen-containing graphdiyne for CO_(2) electroreduction to CH_(4)

Developing Cu single-atom catalysts(SACs)with well-defined active sites is highly desirable for producing CH4 in the electrochemical CO_(2) reduction reaction and understanding the structure-property relationship.Herein,a new graphdiyne analogue with uniformly distributed N_(2)-bidentate(note that N_(2)-bidentate site=N^N-bidentate site;N_(2)≠dinitrogen gas in this work)sites are synthesized.Due to the strong interaction between Cu and the N_(2)-bidentate site,a Cu SAC with isolated undercoordinated Cu-N_(2) sites(Cu1.0/N_(2)-GDY)is obtained,with the Cu loading of 1.0 wt%.Cu1.0/N_(2)-GDY exhibits the highest Faradaic efficiency(FE)of 80.6% for CH_(4) in electrocatalytic reduction of CO_(2) at-0.96 V vs.RHE,and the partial current density of CH_(4) is 160 mA cm^(-2).The selectivity for CH_(4) is maintained above 70% when the total current density is 100 to 300 mA cm^(-2).More remarkably,the Cu1.0/N_(2)-GDY achieves a mass activity of 53.2 A/mgCu toward CH4 under-1.18 V vs.RHE.In situ electrochemical spectroscopic studies reveal that undercoordinated Cu-N_(2) sites are more favorable in generating key ^(*)COOH and ^(*)CHO intermediate than Cu nanoparticle counterparts.This work provides an effective pathway to produce SACs with undercoordinated Metal-N_(2) sites toward efficient electrocatalysis.

Hierarchical CoFe@N-Doped Carbon Decorated Wood Carbon as Bifunctional Cathode in Wearable Zn-Air Battery

Rechargeable Zn-air batteries(ZAB)have drawn extensive attention due to their eco-friendliness and safety.However,the lack of high-performance and low-cost oxygen redox reactions(OER and ORR)catalysts has become one of the main stumbling blocks in their development.Herein,we successfully fabricate a CoFe nanobubble encapsulated in nitrogen-doped carbon nanocage on wood carbon support(CoFe@NC/WC)via pyrolysis of a novel Prussian blue analog(PBA)/spruce precursor.The hierarchical CoFe@NC/WC catalyst exhibits an excellent potential difference of 0.74 V between the OER potential at 10 mA cm^(-2)and half-wave potential of ORR in 0.1 M KOH,comparable to recently reported preeminent electrocatalysts.Further,CoFe@NC/WC shows outstanding electrochemical performance in liquid ZAB,with a peak power density of 138.9 mW cm^(-2)and a specific capacity of 763.5 mAh g^(-1).More importantly,a bacterial cellulose nanofiber reinforced polyacrylic acid(BC-PAA)hydrogel electrolyte shows ultrahigh tensile-breaking stress of 1.58 MPa.In conjunction with the as-prepared CoFe@NC/WC catalyst,BC-PAA-based wearable ZAB displays impressive rechargeability and foldability,and can power portable electronics,such as electronic timer and mobile phone,in bent states.This work provides a new approach toward high-activity and low-cost catalysts for ZAB.

中国农村儿童早期发展:政府投资的效益—成本分析

儿童早期发展(Early Childhood Development, ECD)项目主要目标之一是为儿童接受小学和更高的教育做学前准备。众所周知,ECD项目大部分收益体现在参与项目儿童会有更高的入学率、更少辍学并获得更好的学业表现。然而,中低收入国家往往不了解ECD项目的投资价值,因此,政府迫切需要有相关数据,以便为实施推广ECD项目提供政策决策的参考。本研究利用政府发布的公开数据和相关研究数据,采用世界银行研发的ECD效益成本测算工具,测算了中国政府在农村地区开展ECD项目的效益-成本比。结果表明,在中国农村地区,政府投资ECD项目的回报率非常高,其效益—成本比为4.2-9.3,如果换算为投资回报率的话,大致为7-15%。与政府投资的其它项目相比,这一回报率较高,也与世界上其它国家实施的ECD项目的投资回报率大致相同。因此,从效益-成本角度考虑,中国政府应该大力开展ECD项目,尤其侧重提高农村地区人力资本质量,为中国未来社会经济可持续发展提供良好的人力资本储备。

儿童早期发展项目:拉丁美洲的实践和政策推广

个体生命的最初1000天是大脑发育的关键时期,同时也是人的一生中人口资本投资回报率最高的时期。在拉丁美洲国家如墨西哥和秘鲁,尽管儿童的健康和营养状况已经得到较大改善,但其在认知、语言、社会情感方面仍未得到充分发展,儿童早期发展滞后情况仍然比较严重。为了解决这个问题,拉丁美洲国家在儿童早期发展领域不断进行尝试,通过家访计划等项目改变照养人的养育行为,从而改善儿童早期发展滞后问题。通过介绍拉丁美洲国家儿童早期发展项目的试点(牙买加项目)及其政策推广(秘鲁SAF项目),并用科学的影响评估方法测量项目效果及存在的问题,为中国政府在儿童早期发展领域的实践提供借鉴,希望能够加大国家在儿童早期发展领域的投入,推广解决中国农村贫困地区儿童早期发展问题的政策,共同促进儿童早期的全面发展,提高国家人力资本实力,促进经济发展。

盐城市空气污染对呼吸系统日门诊量关系的时间序列分析

根据盐城市2014-2018年逐日空气污染物监测数据细颗粒物(PM2.5)、可吸入颗粒物(PM10)、二氧化氮(NO2)、二氧化硫(SO2)、臭氧(O3)、气象数据(日平均温度、日平均相对湿度)及市区某三甲综合医院呼吸系统日门诊资料,采用时间序列半参数广义相加模型,以滞后天数最大效应值作为空气污染物对人群呼吸系统日门诊量影响的超额危险度,分析了盐城市空气污染物短期暴露对人群呼吸系统日门诊量的影响。结果表明,2014-2018年盐城市空气PM2.5、PM10、NO2、SO2和O3平均值分别为48.4,81.8,26.3,15.8和111.2 mg/m^3,其中PM2.5、PM10值高于《环境空气质量标准》(GB 3095-2012)二级标准。污染物PM2.5、PM10、NO2、SO2和O3值每升高10 mg/m^3,呼吸系统日门诊量就增加0.52%,0.31%,3.54%,4.36%和0.03%,SO2效应最强。空气污染物的短期暴露影响呼吸系统日门诊量,且存在滞后效应,其中PM2.5、PM10、NO2、SO2影响较大。

盐城市臭氧污染特征及影响因素

对2015—2016年盐城市城区4个空气质量自动监测国控站点的O_3监测数据进行分析,探讨盐城市O_3污染水平、时空分布特征及其与前体物、气象因子之间的关系。结果表明,各站点O_3污染水平较为接近,2016年各站点O_3-8h第90百分位数超标天数较2015年分别下降了43.5%,50.0%,8.7%和43.6%;全年O_3逐月值大致呈双峰分布,高ρ(O_3)主要集中在4—10月;O_3日变化曲线呈明显的单峰分布,一般在05:00—07:00最低,13:00—15:00达到峰值;不同季节的O_3日变化情况有所差异,午后O_3峰值与O_3日变化幅度均在春季最大,冬季最低;NO、NO_2和CO的日变化曲线均呈现出早晚双峰分布,受早高峰影响,一般在07:00左右达到一日中的最大值;O_3与NO_x等前体物均显著负相关,高ρ(O_3)往往出现在高ρ(CO)/ρ(NO_2)时;总体上各站点的ρ(O_3)随风速的增大而增大。

盐城市城区VOCs污染特征及来源解析

2020年4—9月通过离线采样研究了盐城市城区大气中的挥发性有机物(VOCs)浓度水平及组成特征、臭氧生成潜势、二次有机气溶胶生成潜势以及毒性效应等多效应评估和来源贡献。结果表明:盐城市城区VOCs平均体积浓度为35.09×10^(-9),盐塘湖公园站点浓度最高;盐城市VOCs主要组分为含氧有机物(OVOCs)和烷烃。通过挥发性有机物多效应评估发现,关键物种为乙醛、对二乙苯、丙酮、甲苯和间/对二甲苯等。采样期间对VOCs浓度的主要贡献来源为二次生成、工业排放和交通排放。

Correlation between Different Morus alba L. Leaf Nodes and the Change in Leaf Size or Mass

This paper aimed to explore the correlation between Morus alba L. leaf node and its size or mass change and provide a theoretical basis for the development of scientific Morus alba L. cultivation technology. During 2016-2017,the correlation between Morus alba L. leaf node and its size or mass change was investigated and researched. Results showed that through the correlation coefficient analysis,there was a weakly positive correlation between the leaf node and some indicators such as( leaf length ÷ leaf width) and petiole length,there was a weakly negative correlation between the leaf node and some indicators such as leaf width,( leaf length + leaf width),( leaf length × leaf width) and leaf mass,and there was a weakly negative correlation between the leaf node and the other indicators; there was a highly positive correlation between the leaf mass and some indicators such as Morus alba L. leaf length,leaf width,( leaf length + leaf width) and( leaf length × leaf width),there was a significantly positive correlation between the leaf mass and some indicators such as petiole transverse diameter in width and petiole mass,and there was a weakly positive correlation between the leaf mass and some indicators such as petiole transverse diameter in thickness. In terms of significant level of difference,it was found that there was no significant difference in the correlation coefficients between the leaf nodes on the Morus alba L. shoots and some indicators such as leaf length,leaf width,( leaf length + leaf width),( leaf length × leaf width) and leaf mass; there was an extremely significant difference in the correlation coefficients between the leaf mass and some indicators such as Morus alba L. leaf length,leaf width,( leaf length + leaf width),( leaf length × leaf width),petiole transverse diameter in width and petiole mass; there was no significant difference in the correlation coefficients between the leaf mass and the other indicators. The regression analysis was performed on the leaf node and leaf length,leaf width,( leaf length + leaf width),( leaf length × leaf width),( leaf length ÷ leaf width),petiole length,petiole diameter in width,petiole diameter in thickness,petiole mass and leaf mass. Significance F values were0. 4864,0. 1995,0. 2888,0. 3004,0. 2350,0. 2407,0. 8925,0. 5227,0. 7022 and 0. 2000,respectively,that is,there was an extremely significant difference between Morus alba L. leaf node and petiole diameter in width,there was a significant difference between Morus alba L.leaf node and petiole mass,and there was no significant difference between Morus alba L. leaf node and the other indicators. The comparative analysis of quadratic curve regression equation and linear regression equation was performed on some indicators such as leaf length,and it was found that the R value between the leaf node and petiole diameter in width was in line with the logarithmic curve regression equation,and the other R values of quadratic curve regression equation was larger than the other R values of linear regression equation,indicating that different Morus alba L. leaf nodes,leaf length,leaf mass and other indicators were in line with the quadratic curve regression equation. It was concluded that by investigating the leaf node on the Morus alba L. shoots and regression equation,we could predict the leaf size,leaf mass and other indicators,and we could take the leaf node on the Morus alba L. shoots as a main factor affecting the Morus alba L. leaf size and mass.

盐城市秋冬季节PM_(2.5)污染特征及来源分析

于2019年10月—2020年2月在盐城市开展大气PM_(2.5)离线监测,对PM_(2.5)的浓度变化、质量平衡、组分及来源进行了分析。结果表明,监测期间盐城市ρ(PM_(2.5))月均值为43.32~62.59μg/m^(3),其中1月最高;监测期间ρ(PM_(2.5))平均值为54.25μg/m^(3),质量重建后该值为52.38μg/m^(3),与实测值的相关性达到0.98;PM_(2.5)占比最多的成分是硫酸盐、硝酸盐和铵盐(SNA);m(NO_(3)^(-))/m(SO_(4)^(2-))的平均值为2.16,说明监测期间盐城市机动车相比固定源对NO_(2)和SO_(2)有更高的贡献;通过主成分因子分析,可知盐城市秋、冬季节PM_(2.5)主要来源于土壤和扬尘源、燃烧源以及二次无机源。

骨关节活力操练习对青年白领柔韧性影响的研究

目的:探索骨关节活力操对青年白领柔韧性的影响和作用,为大众健身提供理论依据。方法:随机招募60名20-39岁青年白领接受12周,每周3次,每次45分钟的骨关节活力操练习,12周训练前后分别进行关节活动度、转肩握距、俯卧背伸、坐位体前屈等柔韧性指标的测试。结果:1.骨关节活力操练习可以显著增加青年白领肩关节伸展、内收活动度。2.骨关节活力操练习可以显著改善青年白领髋关节伸展、外展活动度。3.骨关节活力操练习可以显著改善青年白领踝关节背屈活动度。4.骨关节活力操练习对青年白领转肩握距、俯卧背伸、坐位体前屈均有良好的促进作用。结论:骨关节活力操融入了日常生活的身体功能训练,可以有效改善青年白领柔韧性,对于保持关节活动度,对抗因增龄和活动减少带来的柔韧性下降,有非常良好的效果,可以降低静坐少动以及不良身体姿势带来的身体隐性损害,是白领全民健身的良好选择。

lncRNA-HOTAIR通过靶向负调控miR-1-3p抑制脂多糖诱导的H9c2大鼠心肌细胞增殖并促进炎症反应

目的探讨长链非编码RNA-HOX转录本反义基因间RNA(lncRNA-HOTAIR)是否通过靶向微小RNA miR-1-3p调控脓毒症的炎症反应。方法利用0.5μg/mL脂多糖(LPS)诱导H9c2大鼠心肌细胞,建立脓毒症心肌细胞损伤模型,将H9c2细胞分为对照组、LPS组、LPS联合HOTAIR小干扰RNA阴性对照(si-NC)组、LPS联合HOTAIR小干扰RNA(si-HOTAIR)组、LPS联合miR-1-3p阴性对照(miR-NC)组、LPS联合miR-1-3p组、LPS联合si-HOTAIR和miR-1-3p拮抗剂阴性(anti-miR-NC)组、LPS联合siHOTAIR和anti-miR-1-3p组。实时定量PCR检测HOTAIR和miR-1-3p表达,CCK-8法检测细胞增殖,Western blot法分析KI-67抗原(ki67)、P21、B细胞淋巴瘤因子2(Bcl2)、Bcl2相关X蛋白(BAX)的蛋白表达,流式细胞术评估细胞凋亡,ELISA测定炎性因子白细胞介素6(IL-6)、肿瘤坏死因子α(TNF-α)水平。双荧光素酶报告实验分析HOTAIR和miR-1-3p的靶向关系。结果LPS组H9c2细胞中HOTAIR表达量高于对照组,miR-1-3p表达量低于对照组。与LPS联合si-NC组比较,LPS联合si-HOTAIR组LPS处理H9c2细胞增殖活性、ki67、Bcl2表达量增多,P21表达量、凋亡率、BAX表达量、IL-6和TNF-α水平降低。HOTAIR靶向调控miR-1-3p的表达。LPS联合miR-1-3p组较LPS联合miR-NC组的H9c2细胞增殖活性、ki67、Bcl2表达量升高,P21表达量、凋亡率、BAX表达量、IL-6、TNF-α水平降低。与LPS联合si-HOTAIR和anti-miR-NC组比较,LPS联合si-HOTAIR和anti-miR-1-3p组H9c2细胞增殖活性降低、ki67、Bcl2表达减少,P21、BAX表达,细胞凋亡、IL-6、TNF-α水平增加。结论HOTAIR通过靶向负调控miR-1-3p的表达,抑制LPS诱导的H9c2心肌细胞增殖,并诱导细胞凋亡和炎症反应。

Geographical features and development models of estuarine cities

Cities are the key areas for human beings to achieve sustainable development goals in the future.Estuarine cities are a special type of coastal city in urgent need of a clear definition.This paper proposed that estuarine cities are cities developed on the coast where rivers and oceans meet and defined four connotations,including the intersection of rivers and marine water systems,the coordinated development of land and oceans,the location advantages of connecting rivers and seas,and the important fragility of the ecological environment.We used Hydro SHEDS,OSM,GPW,and urban socioeconomic statistics and selected 50 estuarine cities with large rivers as representatives to summarize the main geographical basis and socioeconomic characteristics.Cities are primarily found in low-altitude,flat regions with average annual temperatures that mainly vary from 10℃to 25℃,relatively abundant precipitation,and extensive biological resources.There are substantial variations in the socioeconomic features of estuarine cities.We proposed eight development patterns,including open and inclusive city spirit,high-quality livable cities,high-quality development driven by innovation,integration of internal and external communication with ports and cities,construction of an international financial center,ecological environment protection and restoration,active promotion of cultural tourism,and positive international exchanges.

城市化地区实体与流空间演变及高质量发展路径分析

生态文明和美丽中国建设进入关键期,城市化地区是美丽中国地理图景的重要空间载体,人地关系矛盾最为突出,也是美丽中国建设难点。聚焦城市化地区的实体地域,基于大数据技术方法,厘清中国城市不透水面的时空分布与分组演化特征,分析流空间视角下城市体系流动网络的结构特征,提出对新时期促进城市化地区高质量发展途径的初步思考与政策建议。以人为核心建设人民城市、分级分类引导城市多样化发展、绿色韧性健康的城市可持续模式、科技创新功能与智慧城市建设、常态化开展城市体检工作等,支撑中国式城市化现代化与美丽中国目标实现。

Accounting for Polychromatic Light in Virtual Shack-Hartmann Wavefront Sensing

Virtual Shack-Hartmann wavefront sensing(vSHWS)has some significant advantages and is promising for aberration measurement in the field of biomedical optical imaging.The illumination sources used in vSHWS are almost broadband,but are treated as monochromatic sources(only using center wavelength)in current data processing,which may cause errors.This work proposed a data processing method to take into account the multiple wavelengths of the broadband spectrum,named multiple-wavelength centroid-weighting method.Its feasibility was demonstrated through a series of simulations.A wavefront generated with a set of statistical human ocular aberrations was used as the target wavefront to evaluate the performance of the proposed and current methods.The results showed that their performance was very close when used for the symmetrical,but the wavefront error of the proposed method was much smaller than that of the current method when used for the asymmetrical spectrum,especially for the broader spectrum.These results were also validated by using 20 sets of clinical human ocular aberrations including normal and diseased eyes.The proposed method and the obtained conclusions have important implications for the application of vSHWS.

气候变化与多维度可持续城市化

全球大规模城市化和气候变化已是不争的事实,这是全人类需要共同面对和关注的突出问题。当前对于两者之间的复杂关系以及城市化进程如何科学应对气候变化并不清晰,从科学、管理到实践都需要进一步加强探究,以实现全球和区域可持续发展。本文首先给出全球大规模城市化和气候变化发生的基本事实,综述归纳城市化与气候变化的相互影响以及可能机制,城市化导致热岛效应、降水分配不均以及极端天气,并具有局地—区域—全球多尺度叠加效应,加剧了全球气候变化问题;气候变化对城市化的影响主要表现为能源消费变化、死亡率与传染病传播、海平面上升、极端天气对基础设施的破坏、水资源短缺等方面。简要梳理相关的国际研究和行动联盟,从城市化的4个关键维度:人口、土地、经济和社会视角出发,提出适应与减缓气候变化的多维度可持续城市化的分析框架。呼吁加强自然与人文学科交叉,将城市化等人类活动纳入地—气系统,探究人—地—气复杂耦合过程,从城市化为代表的人类活动角度的适应与减缓,或许是应对气候变化的最关键和最现实的路径。

台风“轩岚诺”对盐城O_(3)污染的影响分析

本研究利用2022年9月第11号台风过程系统监测资料,欧洲中心ERA5再分析数据,结合气象要素和空气质量数据,研究了9月3—10日台风“轩岚诺”靠近、转向对盐城臭氧污染的影响。结果表明:台风靠近盐城期间,外围风圈作用下,风速最高达13.7 m∕s,风场为东北风控制,东北方向海上的湿热水汽输送至盐城,带来了零散的降水过程,O_(3)浓度与气温相关性不高,主要为高湿度对O_(3)的生成起到了抑制作用,近地面盛行上升气流,扩散条件较好;台风转向后,与蒙古冷涡合并,风场为西南风控制,内陆地区高温低湿水汽输送至盐城,同时副高北上控制盐城,气温迅速升高,O_(3)浓度与温度正相关性显著达0.88,与湿度负相关性显著达-0.79。高温低湿的大气条件为臭氧生成提供了有利的光化学条件,此外受下沉气流影响,近地面污染物不易扩散,造成了O_(3)中度污染。

改革开放以来中国区域人口与经济重心演进态势及其影响因素

区域协调发展是中国高质量可持续发展和建成富强民主文明和谐美丽的社会主义现代化强国的必然要求,是新时代中国区域经济发展的重要方向。基于此,文章采用1978─2018年中国省域人口和GDP数据,探究四大区域人口与经济重心演进态势及其影响机制。结果显示:(1)四大区域人口与经济重心演进态势差异显著。整体上,人口重心东部向西南移动,中部向东北移动,西部向西北移动,东北向西南移动;经济重心东部向西南移动,中部移动方向持续变化,西部和东北均向西南和东北往复移动。(2)社会经济要素对区域人口密度的影响系数整体较小,工业化水平、交通便利度对人口密度影响相对较大。(3)工业化水平、市场繁荣度对区域经济增长影响相对较大,城镇化与交通便利度对经济增长影响相对较小,经济增长应遵循多要素累积效应的阶段性规律。

基于遗传算法的多用户OFDM系统资源分配策略

针对多用户OFDM系统资源分配算法复杂度高且误码性能不理想等问题,提出了在考虑用户速率情况下保证发射功率最小的子载波和比特分配方案,并通过引入遗传算法使系统通过解的编码、初始群体的生成、构建适应度函数、生成种群、遗传策略、变异规则等过程的改进,得到系统优化问题的全局最优解,同时也使算法复杂度降低.仿真结果表明,在信噪比相同的情况下,该方案可以进一步减小系统的误码率.

Climate change and multi-dimensional sustainable urbanization

Global large-scale urbanization and climate change have become indisputable scientific facts yet are unresolved issues,and are a common concern for mankind.The relationship between these two topics is unclear and it is not known how to deal appropriately at the scientific level with climate change in the process of urbanization.Further exploration of the science,management and practice,are needed to achieve global and regional sustainadevelopment.This paper first considers the basic facts concerning mass urbanization and climate change and summarizes the interactions and possible mechanisms of urbanization and climate change.Urbanization leads to the heat island effect,an uneven distribution of precipitation and extreme weather,together with a local-regional-global multi-scale superposition effect,which aggravates the consequences of global climate change.The impact of climate change on urbanization is mainly manifested in aspects such as changes of energy consumption,mortality,and the spread of infectious diseases,sea level rise,extreme weather damage to infrastructure,and water shortages.This paper also briefly reviews relevant international research programs and action coalitions and puts forward an analysis framework multi-dimensional sustainable urbanization which can adapt to and mitigate climate change,from the perspective of the four key dimensions—population,land use,economy,and society.It is imperative that we strengthen the interdisciplinary activities involving the natural and social sciences,take urbanization and other human activities into consideration of the land-atmosphere system,and explore the human-land-atmosphere coupling process.The adaptation and mitigation from the perspective of human activities,as represented by urbanization,might be the most critical and realistic way to deal with climate change.