High pressure die casting(HPDC)AlSi10Mn Mg alloy castings are widely used in the automobile industry.Mg can optimize the mechanical properties of castings through heat treatment,while the release of thermal stress aro...High pressure die casting(HPDC)AlSi10Mn Mg alloy castings are widely used in the automobile industry.Mg can optimize the mechanical properties of castings through heat treatment,while the release of thermal stress arouses the deformation of large integrated die-castings.Herein,the development of non-heat treatment Al alloys is becoming the hot topic.In addition,HPDC contains externally solidified crystals(ESCs),which are detrimental to the mechanical properties of castings.To achieve high strength and toughness of non-heat treatment die-casting Al-Si alloy,we used AlSi9Mn alloy as matrix with the introduction of Zr,Ti,Nb,and Ce.Their influences on ESCs and mechanical properties were systematically investigated through three-dimensional reconstruction and thermodynamic simulation.Our results reveal that the addition of Ti increased ESCs'size and porosity,while the introduction of Nb refined ESCs and decreased porosity.Meanwhile,large-sized Al_3(Zr,Ti)phases formed and degraded the mechanical properties.Subsequent introduction of Ce resulted in the poisoning effect and reduced mechanical properties.展开更多
Currently the development of automatic control system is mainly based on manual design. This has made the develop-ment process complicated and has made it difficult to guarantee system requirement. This paper presents...Currently the development of automatic control system is mainly based on manual design. This has made the develop-ment process complicated and has made it difficult to guarantee system requirement. This paper presents a Model in-terpretation development architecture built on meta-models and model interpretation. In this modeling and developing process, different meta-models or domain models may be constructed in terms of various system requirements. Inter-preters are used to transform the meta-model into relevant domain model and generate some other formats from do-main models, typically with different semantic domains. An interpretation extension interface is introduced, which can be accelerated to develop the model interpreter. This development architecture can improve system reusability and en-hance development efficiency. Finally, an example is introduced to explain the advantage of method.展开更多
The integration of carbon dots(CDs)with graphitic carbon nitride(g-C_(3)N_(4))has emerged as a promising approach to enhance photocatalytic hydrogen(H_(2))evolution.Despite significant progress,critical challenges rem...The integration of carbon dots(CDs)with graphitic carbon nitride(g-C_(3)N_(4))has emerged as a promising approach to enhance photocatalytic hydrogen(H_(2))evolution.Despite significant progress,critical challenges remain in achieving broad visiblelight absorption and suppressing charge recombination.In this work,we developed a series of photocatalysts through in situ embedding of red-emissive CDs(R-CDs)into g-C_(3)N_(4)(RCN)with precisely controlled loading amounts.Systematic characterization revealed that the R-CDs incorporation simultaneously addresses two fundamental limitations:(1)extending the light absorption edge to 800 nm,and(2)acting as an electron acceptor,facilitating charge separation.The optimized RCN composite demonstrates exceptional H_(2)evolution activity(1.87 mmol·g^(-1)·h^(-1),wavelength(λ)≥420 nm),representing a 3.3-fold enhancement over pristine g-C_(3)N_(4).Remarkably,the apparent quantum efficiency(AQE)reaches 9.1% at 420 nm,while maintaining measurable activity beyond 475 nm,where unmodified g-C_(3)N_(4)shows negligible response.This study provides fundamental insights into band structure engineering and charge carrier management through rational design of CDs-modified semiconductor heterostructures.展开更多
太阳能水蒸发对于解决净水危机潜力无限.随着研究的深入,研发高效光热转换材料和合理的材料结构设计均可以提高光热蒸发速率.因此,我们设计合成了一种双层碳基水凝胶复合材料.在一个太阳光照条件下,其最大蒸发速率可达2.19 kg m^(−2)h^(...太阳能水蒸发对于解决净水危机潜力无限.随着研究的深入,研发高效光热转换材料和合理的材料结构设计均可以提高光热蒸发速率.因此,我们设计合成了一种双层碳基水凝胶复合材料.在一个太阳光照条件下,其最大蒸发速率可达2.19 kg m^(−2)h^(−1),光热转换效率可达93.7%.同时,该复合材料展现了优异的海水淡化性能及良好的稳定性,扩展了实际应用范围.除此之外,其可控规模化及便携性可以自如面对多种复杂的应用环境,成本低廉可以使其大规模应用于经济落后地区,为复合结构水凝胶蒸发器的生产提供了可供参考的设计思路和策略.展开更多
The solar H_(2)generation directly from natural seawater is a sustainable way of green energy.However,it is limited by a low H_(2)generation rate even compared to fresh water.In this report,TiO_(2)is chosen as a model...The solar H_(2)generation directly from natural seawater is a sustainable way of green energy.However,it is limited by a low H_(2)generation rate even compared to fresh water.In this report,TiO_(2)is chosen as a model photocatalyst to disclose the critical factor to deteriorate the H_(2)generation rate from seawater.The simulated seawater(SSW),which is composed of eight ions(Na^(+),K^(+),Ca^(2+),Mg^(2+),Cl^(−),Br^(−),SO_(4)^(2−),and CO_(3)^(2−)),is investigated the effect of each ion on the H_(2)production.The results indicate that all ions have a negative effect at the same concentration as in the seawater except Br−.The CO_(3)^(2−)has the most serious deterioration,and the H_(2)production rate lowers near 40%even at[CO_(3)^(2−)]of 1.5 mmol·L^(−1).The H_(2)production rate can be recovered to 85%if the CO_(3)^(2−)is excluded from the SSW.To understand the reason,the zeta potential of the TiO_(2)treated with different ions aqueous solution reveals that the zeta potential decreases when it is treated with CO_(3)^(2−)and SO_(4)^(2−)due to they can adsorb on the surface of TiO_(2)nanoparticles.Fourier transform infrared(FTIR)and thermogravimetric analysis-mass spectroscopy(TGA-MS)further confirm that the adsorbed ion is mainly from CO_(3)^(2−).Since the pH of seawater is about 8.9 between pKa1(6.37)and pKa2(10.3)of H_(2)CO3,the CO_(3)^(2−)should exist in the form of HCO3−in the seawater.We proposed a simple method to remove the adsorbed HCO3−from the TiO_(2)surface by adjusting the pH below the pKa1.The results indicate that if a trace amount of HCl(adjusting pH~6.0)is added to the SSW,the H_(2)production rate can be recovered to 85%of that in pure water.展开更多
基金financially supported by the National Natural Science Foundation of China(Nos.52175284 and 52474396)the National Key Research and Development Program of China(No.2022YFB3404201)。
文摘High pressure die casting(HPDC)AlSi10Mn Mg alloy castings are widely used in the automobile industry.Mg can optimize the mechanical properties of castings through heat treatment,while the release of thermal stress arouses the deformation of large integrated die-castings.Herein,the development of non-heat treatment Al alloys is becoming the hot topic.In addition,HPDC contains externally solidified crystals(ESCs),which are detrimental to the mechanical properties of castings.To achieve high strength and toughness of non-heat treatment die-casting Al-Si alloy,we used AlSi9Mn alloy as matrix with the introduction of Zr,Ti,Nb,and Ce.Their influences on ESCs and mechanical properties were systematically investigated through three-dimensional reconstruction and thermodynamic simulation.Our results reveal that the addition of Ti increased ESCs'size and porosity,while the introduction of Nb refined ESCs and decreased porosity.Meanwhile,large-sized Al_3(Zr,Ti)phases formed and degraded the mechanical properties.Subsequent introduction of Ce resulted in the poisoning effect and reduced mechanical properties.
文摘Currently the development of automatic control system is mainly based on manual design. This has made the develop-ment process complicated and has made it difficult to guarantee system requirement. This paper presents a Model in-terpretation development architecture built on meta-models and model interpretation. In this modeling and developing process, different meta-models or domain models may be constructed in terms of various system requirements. Inter-preters are used to transform the meta-model into relevant domain model and generate some other formats from do-main models, typically with different semantic domains. An interpretation extension interface is introduced, which can be accelerated to develop the model interpreter. This development architecture can improve system reusability and en-hance development efficiency. Finally, an example is introduced to explain the advantage of method.
基金financially supported by the National Key R&D Program of China(No.2023YFB3810800)the National Natural Science Foundation of China(Nos.22579008,22502012,22301013,and 22272003)+3 种基金Key Project of the National Natural Science Foundation of China(No.21936001)R&D Program of Beijing Municipal Education Commission(No.KZ20231000506)Beijing Outstanding Young Scientists Program(No.BJJWZYJH01201910005017)the Project of Construction of Innovative Teams and Teacher Career Development for Universities and Colleges Under Beijing Municipality(No.11000024T000003219982).
文摘The integration of carbon dots(CDs)with graphitic carbon nitride(g-C_(3)N_(4))has emerged as a promising approach to enhance photocatalytic hydrogen(H_(2))evolution.Despite significant progress,critical challenges remain in achieving broad visiblelight absorption and suppressing charge recombination.In this work,we developed a series of photocatalysts through in situ embedding of red-emissive CDs(R-CDs)into g-C_(3)N_(4)(RCN)with precisely controlled loading amounts.Systematic characterization revealed that the R-CDs incorporation simultaneously addresses two fundamental limitations:(1)extending the light absorption edge to 800 nm,and(2)acting as an electron acceptor,facilitating charge separation.The optimized RCN composite demonstrates exceptional H_(2)evolution activity(1.87 mmol·g^(-1)·h^(-1),wavelength(λ)≥420 nm),representing a 3.3-fold enhancement over pristine g-C_(3)N_(4).Remarkably,the apparent quantum efficiency(AQE)reaches 9.1% at 420 nm,while maintaining measurable activity beyond 475 nm,where unmodified g-C_(3)N_(4)shows negligible response.This study provides fundamental insights into band structure engineering and charge carrier management through rational design of CDs-modified semiconductor heterostructures.
基金financially supported by the National Natural Science Foundation of China(21805004,21872001,51801006,and 21671011)Beijing Municipal High-Level Innovative Team Building Program(IDHT20180504)+2 种基金Beijing Outstanding Young Scientists Program(BJJWZYJH01201910005017)Beijing Natural Science Foundation(2192005)Beijing Municipal Science and Natural Science Fund Project(KM201910005016).
文摘太阳能水蒸发对于解决净水危机潜力无限.随着研究的深入,研发高效光热转换材料和合理的材料结构设计均可以提高光热蒸发速率.因此,我们设计合成了一种双层碳基水凝胶复合材料.在一个太阳光照条件下,其最大蒸发速率可达2.19 kg m^(−2)h^(−1),光热转换效率可达93.7%.同时,该复合材料展现了优异的海水淡化性能及良好的稳定性,扩展了实际应用范围.除此之外,其可控规模化及便携性可以自如面对多种复杂的应用环境,成本低廉可以使其大规模应用于经济落后地区,为复合结构水凝胶蒸发器的生产提供了可供参考的设计思路和策略.
基金supported by the National Natural Science Foundation of China(21872001,51801006,21805004,and 21671011)Beijing Municipal High Level Innovative Team Building Program(IDHT20180504)+2 种基金Beijing Outstanding Young Scientists Program(BJJWZYJH01201910005017)Beijing Natural Science Foundation(2192005)Beijing Municipal Science and Natural Science Fund Project(KM201910005016)。
文摘水体污染是当前造成淡水短缺的主要原因之一.利用太阳能水蒸发装置从海水或污水中生产淡水是一种简单有效且节能的解决淡水危机的方式,引起了广泛的关注.然而,污染物的共同蒸发或沉积可能会降低水蒸发过程中的效率和淡水质量.本文基于天然木质纤维素(NCF)、聚苯胺(PANI)和二氧化钛(TiO_(2))开发了自清洁太阳能水蒸发器,其具有宽吸收、亲水性强、导热系数低等优点.通过在聚合物溶液中加入木质纤维素,聚苯胺纳米纤维在NCF表面聚合形成介孔网络.P25 TiO_(2)纳米颗粒作为光催化剂分散到上述反应液中,通过简单的过滤形成PANI/TiO_(2)/NCF复合材料.由于太阳水蒸发器装置中PANI的光热效应与TiO_(2)纳米颗粒的光催化降解的协同作用,水蒸发速率可达2.36 kg m^(-2)h^(-1)(1个太阳光照射下),且可有效降解污染物(100 ppm四环素).更重要的是,在工作10 h后,该太阳能水蒸发器装置仍然保持稳定的水蒸发速率,且没有污染物的积聚.光催化和光热效应相结合的双功能太阳能水蒸发装置在有机污染物水中具有自清洁作用,具有很大的应用潜力.
基金financially supported by the National Natural Science Foundation of China(21872001,51801006,21805004,and 21671011)Beijing Municipal High Level Innovative Team Building Program(IDHT20180504)+2 种基金Beijing Outstanding Young Scientists Program(BJJWZYJH01201910005017)Beijing Natural Science Foundation(2192005)Beijing Municipal Science and Natural Science Fund Project(KM201910005016)。
基金supported by the National Natural Science Foundation of China(Nos.21872001,22272003,21805004,and 51801006)the Beijing Municipal High-Level Innovative Team Building Program(No.IDHT 20180504)+3 种基金Beijing Outstanding Young Scientists Program(No.BJJWZYJH0201910005017)Beijing Natural Science Foundation(Nos.KZ201710005002 and 2192005)Beijing Municipal Science and Natural Science Fund Project(No.KM201910005016)these funding agencies are acknowledged.
文摘The solar H_(2)generation directly from natural seawater is a sustainable way of green energy.However,it is limited by a low H_(2)generation rate even compared to fresh water.In this report,TiO_(2)is chosen as a model photocatalyst to disclose the critical factor to deteriorate the H_(2)generation rate from seawater.The simulated seawater(SSW),which is composed of eight ions(Na^(+),K^(+),Ca^(2+),Mg^(2+),Cl^(−),Br^(−),SO_(4)^(2−),and CO_(3)^(2−)),is investigated the effect of each ion on the H_(2)production.The results indicate that all ions have a negative effect at the same concentration as in the seawater except Br−.The CO_(3)^(2−)has the most serious deterioration,and the H_(2)production rate lowers near 40%even at[CO_(3)^(2−)]of 1.5 mmol·L^(−1).The H_(2)production rate can be recovered to 85%if the CO_(3)^(2−)is excluded from the SSW.To understand the reason,the zeta potential of the TiO_(2)treated with different ions aqueous solution reveals that the zeta potential decreases when it is treated with CO_(3)^(2−)and SO_(4)^(2−)due to they can adsorb on the surface of TiO_(2)nanoparticles.Fourier transform infrared(FTIR)and thermogravimetric analysis-mass spectroscopy(TGA-MS)further confirm that the adsorbed ion is mainly from CO_(3)^(2−).Since the pH of seawater is about 8.9 between pKa1(6.37)and pKa2(10.3)of H_(2)CO3,the CO_(3)^(2−)should exist in the form of HCO3−in the seawater.We proposed a simple method to remove the adsorbed HCO3−from the TiO_(2)surface by adjusting the pH below the pKa1.The results indicate that if a trace amount of HCl(adjusting pH~6.0)is added to the SSW,the H_(2)production rate can be recovered to 85%of that in pure water.
