反应条件对氮(碳/氧)化硅薄膜性能的影响

就氮(碳/氧)化硅薄膜的反应条件-组成和结构-性能之间关系的国内外研究进行了综述。

运用方解石脉包裹体和碳氧同位素评价页岩气保存条件——以中扬子地区寒武系为例

裂缝脉体的碳/氧同位素和包裹体对于研究油气保存条件有着重要的指示意义。为了揭示中扬子地区寒武系页岩气保存条件的差异性,选取该区3口代表不同构造条件和含气性的井(YY1井、YD4井、ZD1井)作为主要的研究对象,基于裂缝脉体包裹体和方解石脉碳/氧同位素测试分析资料开展了对比研究。研究结果表明:①该区寒武系裂缝脉体包裹体主要有液烃包裹体、甲烷包裹体、气液两相包裹体、盐水包裹体4种类型,(液烃+甲烷)包裹体/(气液两相+盐水)包裹体比值与油包裹体丰度一样对油气成藏与保存具有重要的指示意义,YY1井以高演化液烃和甲烷包裹体为主,ZD1井以气液两相和盐水包裹体为主,YD4井介于二者之间,构造条件越复杂古流体中烃类的占比越低,水的比例越高;②Δ13C (δ13C围岩-δ13C方解石)值、Δ18O(δ18O围岩-δ18O方解石)值的变化范围与保存条件具有相关性,ZD1井的变化范围明显大于YY1井,高度封闭的页岩段Δ13C值、Δ18O值趋近于0,页岩内部跨层流体、外部流体侵入都会导致Δ13C值、Δ18O值变化;③包裹体及方解石脉碳/氧同位素指示YY1井裂缝导致页岩气向上散失,YD4井、ZD1井裂缝导致页岩气向下散失两种不同逸散类型;④初步建立了中扬子地区基于包裹体和方解石脉碳/氧同位素的寒武系页岩气保存条件评价指标。结论认为,中扬子地区寒武系页岩气保存条件由黄陵隆起向江南-雪峰隆起整体逐渐变差,黄陵隆起周缘的寒武系页岩是下一步页岩气勘探的重点。

现代碳／氧测井：确定含油气饱和度的技术

碳／氧（C／O）测井技术的新进展为储层监测工程提供了更加定量的测量结果，特别是在混合矿化度的条件下。虽然革新带来了重大改进，但是，不同服务公司所提供的流体饱和度剖面往往是不同的。这些变化是由于仪器设计和解释方法的差异引起的。在中东一个大型碳酸盐岩油田进行了一项研究，对不同类型的脉冲中子能谱（PNS）测井仪在控制环境下的准确性和精确度进行了评价和比较。

甘肃省二氧化碳排放影响因素的灰色关联分析

二氧化碳排放造成的气候变化问题越来越受到全世界的关注,影响二氧化碳排放的因素很多,本文运用灰色系统理论中的相对关联度求出了各因素对二氧化碳排放量的影响程度,得到城市化水平和产业结构对二氧化碳排放量的影响最大,而经济增长的影响最小,进而使用脱钩理论分析了经济增长与二氧化碳排放量的脱钩关系,得出他们之间逐渐脱钩的趋势,从而进一步验证了灰色关联分析得出的经济增长与二氧化碳排放量影响较小的结论。最后针对研究结果提出了发展低碳城市、调整产业结构等相关减排建议。

超级电容器用氮/氧共掺杂多孔碳纳米材料的制备及性能研究

超级电容器作为一种新型的储能装置,而电极是决定超级电容器电化学性能的核心部件。在研究工作中,利用D-无水葡萄糖为碳源、三聚氰胺为氮源和NaHCO3为致孔剂成功合成了一种氮/氧共掺杂碳纳米材料用于高性能超级电容器。在电流密度为1 Ag-1时,电极材料的比电容可达165 Fg-1(6 M KOH电解液)。采用合成方法可以成功实现整个合成制备工艺过程中的无醛化,为电极材料的制备开辟了一条新型绿色的道路。

甲烷在官能团化石墨中吸附的分子模拟

页岩中干酪根结构简化为不同碳/氧比的石墨结构,利用分子模拟方法研究甲烷分子在不同碳/氧比石墨中赋存微观结构,并研究不同孔径和不同压力对甲烷在不同碳/氧比石墨中吸附行为的影响,在此基础上讨论碳/氧比变化对甲烷吸附行为的影响。研究结果表明:甲烷的平均等量吸附热随着孔径增大而下降,或随着碳/氧比增加而下降,且甲烷平均等量吸附热小于42kJ/mol,说明甲烷在不同碳/氧比石墨中吸附属于物理吸附;不同碳/氧比石墨微孔中,甲烷吸附量随着孔径增大而增大,而中孔中,甲烷吸附量随着孔径增大而减小;在相同孔径中,甲烷吸附量随着碳/氧比增加而减小,甲烷分子在孔中吸附气量占比随着压力增大而呈下降趋势;相同压力下,甲烷分子在孔中吸附气量占比随着孔径增大而减小。

Insights into Reduction of CO_(2)to CO Catalyzed by Pyramidal-4Ni Clusters Supported on Doped CeO_(2)

Converting CO_(2)into valuable chemicals has become a widely used research method for CO_(2)conversion.In this work,the catalytic performance of pyramidal-4Ni catalysts supported on rare earth metal-doped CeO_(2)towardCO_(2)reductionreaction(CO_(2)RR)was investigated by using density-functional theorycalculations.For rare earth metal-doped CeO_(2),2Ce is substituted by 2 trivalent cations and at the same time one oxygen vacancy is created to make charge compensation.We investigated the oxygen vacancy nearest(Vo,N)and next-nearest(Vo,NN)to 4Ni,and found releasing CO and CO_(2)dissociation are the rate-determining steps,respectively,via the path of Vo,N and Vo,NN.Among the studied dopants(Ga,Sb,Lu,Gd,Pr,La,Bi),Gd is identified as the best dopant for catalyzing the reduction of CO_(2)at 823 K,with the turn-over frequency(TOF)of 104 times as large as that over 4Ni supported on pure CeO_(2).This exploration provides theoretical support and guidance for the research and application of rare earth metaldoped CeO_(2)-loaded Ni catalysts in the field of CO_(2)reduction.

Boosting CO_(2) photoreduction by synergistic optimization of multiple processes through metal vacancy engineering

The photoreduction of greenhouse gas CO_(2) using photocatalytic technologies not only benefits en-vironmental remediation but also facilitates the production of raw materials for chemicals.Howev-er,the efficiency of CO_(2) photoreduction remains generally low due to the challenging activation of CO_(2) and the limited light absorption and separation of charge.Defect engineering of catalysts rep-resents a pivotal strategy to enhance the photocatalytic activity for CO_(2),with most research on met-al oxide catalysts focusing on the creation of anionic vacancies.The exploration of metal vacancies and their effects,however,is still underexplored.In this study,we prepared an In2O3 catalyst with indium vacancies(VIn)through defect engineering for CO_(2) photoreduction.Experimental and theo-retical calculations results demonstrate that VIn not only facilitate light absorption and charge sepa-ration in the catalyst but also enhance CO_(2) adsorption and reduce the energy barrier for the for-mation of the key intermediate*COOH during CO_(2) reduction.Through metal vacancy engineering,the activity of the catalyst was 7.4 times,reaching an outstanding rate of 841.32μmol g(-1)h^(-1).This work unveils the mechanism of metal vacancies in CO_(2) photoreduction and provides theoretical guidance for the development of novel CO_(2) photoreduction catalysts.

Hydration transformation behaviors of CO_(2) and excellent anti-inflammatory activity on RAW 264.7 cell

Skin care products with carbonic acid(H_(2)CO_(3))have gained extensive attention worldwide.However,the conversion of CO_(2) to H_(2)CO_(3) is not stable,and the mechanism of the effect of H_(2)CO_(3) on skin care has not been clearly proved.The hydration-dissolution behaviors of CO_(2) were investigated under different temperature,pH,and pressure conditions.Moreover,based on the phenomenon of CO_(2) hydration transformation,the inflammatory effect of CO_(2) hydrate on macrophages(RAW 264.7)was investigated.The result shows that the increase in temperature weakened the hydration of CO_(2),and the increase in pH and pressure both promoted the water-phase transformation of CO_(2).When pH<6,CO_(2) reacts with water to generate H_(2)CO_(3).When pH was between 6-7,the prompt solution was a mixture of H_(2)CO_(3) and HCO_(3)^(-).When the pH was between 7-9,they mainly generated HCO_(3)^(-).And when pH>9,CO_(2) solubility mainly converts to CO_(3)^(2-).Besides,CO_(2) can inhibit the secretion of inflammatory factors by RAW 264.7 cells by inhibiting the phosphorylation of the p38 protein.CO_(2) hydrate inhibited the expression of pro-inflammatory factors IL-6,TNF-α,and up-regulated the expression of anti-inflammatory factor IL-10.Furthermore,the anti-inflammatory molecular mechanism of CO_(2) hydration inhibited the MAPK signaling pathway by inhibiting the phosphorylation of p38.The hydration-dissolution behavior of CO_(2) was investigated.This work revealed the anti-inflammatory bioeffect of CO_(2) hydrate,providing a theoretical basis and application support for CO_(2) skin care products.

3D seismic forward modeling from the multiphysical inversion at the Ketzin CO_(2) storage site

From June 2008 to August 2013,approximately 67 kt of CO_(2) was injected into a deep saline formation at the Ketzin pilot CO_(2) storage site.During injection,3D seismic surveys have been performed to monitor the migration of sequestered CO_(2).Seismic monitoring results are limited by the acquisition and signal-to-noise ratio of the acquired data.The multiphysical reservoir simulation provides information regarding the CO_(2) fluid behavior,and the approximated model should be calibrated with the monitoring results.In this work,property models are delivered from the multiphysical model during 3D repeated seismic surveys.The simulated seismic data based on the models are compared with the real data,and the results validate the effectiveness of the multiphysical inversion method.Time-lapse analysis shows the trend of CO_(2) migration during and after injection.

Advances in the studies of the supported ruthenium catalysts for CO_(2) methanation

CO_(2) methanation has a potential in the large-scale utilization of carbon dioxide.It has also been considered to be useful for the renewable energy storage.The commercial pipeline for natural gas transportation can be directly applied for the methane product of CO_(2) methanation.The supported ruthenium(Ru)catalyst has been confirmed to be active and stable for CO_(2) methanation with its high ability in the dissociation of hydrogen and the strong binding of carbon monoxide.CO_(2) methanation over the supported Ru catalyst is structure sensitive.The size of the Ru catalyst and the support have significant effects on the activity and the mechanism.A significant challenge re-mained is the structural controllable preparation of the supported Ru catalyst toward a sufficiently high low-temperature activity.In this review,the recent progresses in the investigations of the supported Ru catalysts for CO_(2) methanation are summarized.The challenges and the future devel-opments are also discussed.

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.

Experimental study on the properties of CMTs-incorporated geopolymers prepared at low temperatures

Considering that copper mine tailings(CMTs)are commonly mixed with ordinary Portland cement,fly ash(FA),and kaolin to produce geopolymers,to make full use of CMTs,the properties of geopolymers manufactured under different material mass ratios and curing methods(standard curing,water bath curing,and 60℃curing)are evaluated with significantly increased dosage of CMTs.Porosity and unconfined compressive strength tests,X-ray diffraction,field emission scanning electron microscopy,and energy dispersive spectroscopy are used to determine the physical and mechanical properties,microstructure,and mineral composition of geopolymers.Finally,costs and CO 2 emissions of specimens with different material mass ratios during the preparation processes are compared.The results show that during the geopolymerization of low-calcium materials,various geopolymer gels,including calcium silicate,calcium silicoaluminate,and mainly sodium silicoaluminate gels,coexist.The solid waste,cost,and carbon dioxide emission reductions can reach 100%,166.3 yuan/t,and 73.3 kg/t,respectively.Under a curing condition of 60℃,the sample with a CMTs mass fraction of 70%and an FA mass fraction of 30%meets the requirements of porosity,compressive strength.The resource utilization of CMT and FA is realized in a more economical way.

Enhancing selectivity in acidic CO_(2) electrolysis:Cation effects and catalyst innovation

The electrochemical reduction of CO_(2)(eCO_(2)R)under ambient conditions is crucial for reducing carbon emissions and achieving carbon neutrality.Despite progress with alkaline and neutral electrolytes,their efficiency is limited by(bi)carbonates formation.Acidic media have emerged as a solution,addressing the(bi)carbonates challenge but introducing the issue of the hydrogen evolu-tion reaction(HER),which reduces CO_(2) conversion efficiency in acidic environments.This review focuses on enhancing the selectivity of acidic CO_(2) electrolysis.It commences with an overview of the latest advancements in acidic CO_(2) electrolysis,focusing on product selectivity and electrocatalytic activity enhancements.It then delves into the critical factors shaping selectivity in acidic CO_(2) electrolysis,with a special emphasis on the influence of cations and catalyst design.Finally,the research challenges and personal perspectives of acidic CO_(2) electrolysis are suggested.

Chalcogen heteroatoms doped nickel-nitrogen-carbon single-atom catalysts with asymmetric coordination for efficient electrochemical CO_(2) reduction

The electronic configuration of central metal atoms in single-atom catalysts(SACs)is pivotal in electrochemical CO_(2) reduction reaction(eCO_(2)RR).Herein,chalcogen heteroatoms(e.g.,S,Se,and Te)were incorporated into the symmetric nickel-nitrogen-carbon(Ni-N_(4)-C)configuration to obtain Ni-X-N_(3)-C(X:S,Se,and Te)SACs with asymmetric coordination presented for central Ni atoms.Among these obtained Ni-X-N_(3)-C(X:S,Se,and Te)SACs,Ni-Se-N_(3)-C exhibited superior eCO_(2)RR activity,with CO selectivity reaching~98% at-0.70 V versus reversible hydrogen electrode(RHE).The Zn-CO_(2) battery integrated with Ni-Se-N_(3)-C as cathode and Zn foil as anode achieved a peak power density of 1.82 mW cm^(-2) and maintained remarkable rechargeable stability over 20 h.In-situ spectral investigations and theoretical calculations demonstrated that the chalcogen heteroatoms doped into the Ni-N_(4)-C configuration would break coordination symmetry and trigger charge redistribution,and then regulate the intermediate behaviors and thermodynamic reaction pathways for eCO_(2)RR.Especially,for Ni-Se-N_(3)-C,the introduced Se atoms could significantly raise the d-band center of central Ni atoms and thus remarkably lower the energy barrier for the rate-determining step of ^(*)COOH formation,contributing to the promising eCO_(2)RR performance for high selectivity CO production by competing with hydrogen evolution reaction.

Research on High-Velocity Impact Damage Monitoring Method of CFRP Based on Guided Wave

Carbon fiber-reinforced polymer(CFRP)is widely used in aerospace applications.This kind of material may face the threat of high-velocity impact in the process of dedicated service,and the relevant research mainly considers the impact resistance of the material,and lacks the high-velocity impact damage monitoring research of CFRP.To solve this problem,a real high-velocity impact damage experiment and structural health monitoring(SHM)method of CFRP plate based on piezoelectric guided wave is proposed.The results show that CFRP has obvious perforation damage and fiber breakage when high-velocity impact occurs.It is also proved that guided wave SHM technology can be effectively used in the monitoring of such damage,and the damage can be reflected by quantifying the signal changes and damage index(DI).It provides a reference for further research on guided wave structure monitoring of high/hyper-velocity impact damage of CFRP.

Series Reports from Professor Wei's Group of Chongqing University:Advancements in Electrochemical Energy Conversions(1/4):Report 1:High-performance Oxygen Reduction Catalysts for Fuel Cells

Two major challenges,high cost and short lifespan,have been hindering the commercialization process of lowtemperature fuel cells.Professor Wei's group has been focusing on decreasing cathode Pt loadings without losses of activity and durability,and their research advances in this area over the past three decades are briefly reviewed herein.Regarding the Pt-based catalysts and the low Pt usage,they have firstly tried to clarify the degradation mechanism of Pt/C catalysts,and then demonstrated that the activity and stability could be improved by three strategies:regulating the nanostructures of the active sites,enhancing the effects of support materials,and optimizing structures of the three-phase boundary.For Pt-free catalysts,especialiy carbon-based ones,several strategies that they proposed to enhance the activity of nitrogen-/heteroatom-doped carbon catalysts are firstly presented.Then,an indepth understanding of the degradation mechanism for carbon-based catalysts is discussed,and followed by the corresponding stability enhancement strategies.Also,the carbon-based electrode at the micrometer-scale,faces the challenges such as low active-site density,thick catalytic layer,and the effect of hydrogen peroxide,which require rational structure design for the integral cathodic electrode.This review finally gives a brief conclusion and outlook about the low cost and long lifespan of cathodic oxygen reduction catalysts.