摘要：合理设计并制备新型氮化碳是化学和材料领域的研究热点.本文受尿素聚合的启发,以草酰二胺替代部分尿素制备了C-C桥联、结构接近C_(6)N_(7)的新型氮化碳UO_(x)(x为尿素与草酰二胺的物质的量之比,x=1、1.5、2、2.5和3).密度泛函理论计算表明,UO_(x)的共轭性由单个庚嗪环扩展到了整个材料框架.因此,其禁带宽度缩小到2.05 e V,吸收带边被大幅扩展到600 nm.此外,它的载流子传输和分离也得到显著增强,因而展现出优异的光催化活性.在一系列样品中,UO_(2)具有最佳的光催化活性,其光催化析氢速率约为108.59μmol h^(-1)(10mg催化剂),表观量子效率在420和600 nm下分别为36.12%和0.33%.此外,UO_(2)对二苯肼氧化以及酚类降解也呈现明显优于传统g-C_(3)N_(4)的优异光催化活性和稳定性,它是一类极具发展前景的新型二维材料.

摘要：高能量密度的锂离子电池先进电极材料的开发,依赖于对材料在电池循环中的运行和失效机制的理解.本文使用原位高分辨TEM技术跟踪了Sb_(2)Se_(3)单晶锂化/脱锂过程中的相变,并揭示了反应界面处的电化学-力学耦合.这种电化学-力学耦合效应对锂化动力学具有复杂的相互作用,并在反应前端引起各种类型的缺陷,包括位错对、反相边界和裂纹.另一方面,形成的裂缝和相关缺陷为锂离子的快速扩散开辟了道路,并在扭曲的反应前沿引发高度各向异性的锂化,从而在无定形Li_(x)Sb_(2)Se_(3)中形成可能“失效”的Sb_(2)Se_(3)畴.我们对Sb_(2)Se_(3)电化学过程机理的详细研究有助于更合理地设计和制备高容量电极材料.

摘要：与宏观块材不同,纳米材料高的表面能赋予其亚稳态特性,使其对外界变化十分敏感.当纳米颗粒与外界发生强烈相互作用(溶解、酸解等)时,这些高度不稳定的纳米颗粒将通过一系列持续的调整过程(结构重组、化学转化等)来达到一个新的稳态,而合理地利用这些调整过程可实现功能纳米材料的非常规设计和制备.本文基于ZnSe[DETA]0.5有机无机杂化纳米带的低稳定性提出了一种氧化石墨烯非常规化学石墨化和功能化新策略.在强酸作用下,H^+离子会质子化ZnSe[DETA]0.5纳米带中的DETA分子,使得原本被DETA分子所稳定的ZnSe无机片层变得极为不稳定,释放出高还原性的Se^2−阴离子.这些高还原性的Se2−阴离子与溶液中的氧化石墨烯纳米片相互作用,在室温条件下即可对其进行非常规化学还原和掺杂.此外,由于Se^2−/Se较低的还原电势(−0.924V),通过控制Se^2−阴离子的氧化过程和后处理过程,可分别得到Se/(Se+ZnSe)/ZnSe与还原石墨烯的三种不同复合材料;其中,Se-还原石墨烯复合材料又可作为前驱体进一步通过物理/化学过程形成Se纳米线/Cu2Se/Ag2Se/Pt与还原石墨烯复合材料.显然,合理地利用纳米材料的不稳定过程可以为构建各种功能纳米材料提供一个非常规设计和制备平台.

摘要：以英国北爱尔兰Hayes的一块牧草地为研究区,将所有样点分为独立的训练和检验数据集,并在训练样点集的基础上设计了其他4种样点布局方案,以研究神经网络集成技术应用于田间土壤性质空间变异性的可能性。与广泛应用的克里格法的试验结果相比,集成BP神经网络的插值结果精度与之基本相当,尤其是在样点分布较稀疏和样点数较少的情况下,集成BP网络表现出明显的优势;由于神经网络集成方法对样本数据的分布没有任何要求,因此具有较广泛的应用前景和潜力,并在不符合克里格法对样本数据分布要求的情况下是一种可行的替代方法。

摘要：本文报道了一种钴-钼双金属碳化物(Co3Mo3C)催化材料用于修饰锂硫电池隔膜,强化多硫化锂的化学吸附和催化转化.所组装的电池表现出优异的电化学性能,即使在8.0 mg cm^-2的硫面积负载量条件下,面积比容量仍高达6.8 mA h cm^-2.理论计算结果表明,相比于单一金属碳化物Mo2C,双金属碳化物Co3Mo3C具有更多的活性位点,更利于化学固定多硫化锂,并催化多硫化锂间相互转化;同时,Ni3Mo3C和Fe3Mo3C亦表现出类似的高催化活性.本研究对高性能锂硫电池关键催化材料的设计具有一定的指导意义.

摘要：A grand challenge facing society is climate change caused mainly by rising CO_(2) concentration in Earth’s *** plants are linchpins in global carbon cycling,with a unique capability of capturing CO_(2) via photosynthesis and translocating captured carbon to stems,roots,and soils for long-term ***,many researchers postulate that existing land plants cannot meet the ambitious requirement for CO_(2) removal to mitigate climate change in the future due to low photosynthetic efficiency,limited carbon allocation for long-term storage,and low suitability for the *** address these limitations,there is an urgent need for genetic improvement of existing plants or construction of novel plant systems through biosystems design(or biodesign).Here,we summarize validated biological parts(e.g.,protein-encoding genes and noncoding RNAs)for biological engineering of carbon dioxide removal(CDR)traits in terrestrial plants to accelerate land-based decarbonization in bioenergy plantations and agricultural settings and promote a vibrant ***,we first summarize the framework of plant-based CDR(e.g.,CO_(2) capture,translocation,storage,and conversion to value-added products).Then,we highlight some representative biological parts,with experimental evidence,in this ***,we discuss challenges and strategies for the identification and curation of biological parts for CDR engineering in plants.

摘要：All living organisms share similar reactions within their central metabolism to provide precursors for all essential building blocksand reducing power. To identify whether alternative metabolic routes of glycolysis can operate in E. coli, we complementarilyemployed in silico design, rational engineering, and adaptive laboratory evolution. First, we used a genome-scale model andidentified two potential pathways within the metabolic network of this organism replacing canonical Embden-Meyerhof-Parnas(EMP) glycolysis to convert phosphosugars into organic acids. One of these glycolytic routes proceeds via methylglyoxal andthe other via serine biosynthesis and degradation. Then, we implemented both pathways in E. coli strains harboring defectiveEMP glycolysis. Surprisingly, the pathway via methylglyoxal seemed to immediately operate in a triosephosphate isomerasedeletion strain cultivated on glycerol. By contrast, in a phosphoglycerate kinase deletion strain, the overexpression ofmethylglyoxal synthase was necessary to restore growth of the strain. Furthermore, we engineered the “serine shunt” whichconverts 3-phosphoglycerate via serine biosynthesis and degradation to pyruvate, bypassing an enolase deletion. Finally, toexplore which of these alternatives would emerge by natural selection, we performed an adaptive laboratory evolution studyusing an enolase deletion strain. Our experiments suggest that the evolved mutants use the serine shunt. Our study reveals theflexible repurposing of metabolic pathways to create new metabolite links and rewire central metabolism.

摘要：综述了工业水处理用有机胺类、咪唑啉类、氨基羧酸类和硫代羧酸类缓蚀剂的作用机理、制备方法和专利技术进展。通过对大量申请专利的技术分析,指出中国无磷有机缓蚀剂开发中存在的主要问题是原创性品种不足。建议根据分子结构和缓蚀性能的关系,设计一些新型无磷有机缓蚀剂分子并对现有无磷有机缓蚀剂分子进行化学反应改性,以增加高效无磷有机缓蚀剂新品种。

摘要：该文运用CLUE-S模型模拟研究了贵州中部猫跳河流域在不同情景模式下未来十年内土地覆被的空间变化情况。根据研究区土地覆被结构的现状以及影响土地覆被变化的宏观因素,作者设计了生态安全目标、粮食安全目标、经济发展目标以及综合发展目标等4种可能出现的情景。结果表明,在不同土地利用情景下,猫跳河流域未来十年的土地覆被格局及其效应存在明显的差别。生态安全目标情景能在较大程度上改善流域的生态环境,但会对流域的粮食安全构成较大的威胁。粮食安全目标情景能够保障流域的粮食安全,但会导致区域生态环境质量下降。经济发展目标模式可充分保障经济建设用地的需求,但会威胁到流域的粮食安全。综合发展目标情景比较全面地考虑到了流域经济发展、生态保护以及粮食安全等需要,是研究区未来较为可取的土地利用模式。

摘要：Geographic and Geospatial information systems (GISs) have especially benefited from increased development of their inherent capabilities and improved deployment. These systems offer a wide range of services, for example, user-friendly forms that interact with the geospatial components for locational information and geographic extents. An online distributed platform was designed for forest resource management with map elements residing on a GIS platform. This system is accessible on non-authenticated browsers optimized for desktops;whereas the online resource management forms are also accessible on mobile platforms. The system was primarily designed to aid foresters in implementing resource management plans or track threats to forest resource. Baseline data from the system can be easily visualized and mapped. Other data from the systemcan provide input for stochastic analyses especially with respect to forest resource management.