Electronic Structures of Graphene Layers on Metal Foil: Effect of Point Defects

Here we report a facile method to generate a high density of point defects in graphene on metal foil and show how the point defects affect the electronic structures of graphene layers. Our scanning tunneling microscopy (STM) measurements, complemented by first principle calculations, reveal that the point defects result in both the intervalley and intravalley scattering of graphene. The Fermi velocity is reduced in the vicinity area of the defect due to the enhanced scattering. Additionally, our analysis further points out that periodic point defects can tailor the electronic properties of graphene by introducing a significant bandgap, which opens an avenue towards all-graphene electronics.Comment: 4 figure

A Review on the Application of 3D Printing Technology in Pavement Maintenance

To examine the application and significance of 3D printing technology in pavement maintenance engineering, a review of the current developments in principles, types, materials, and equipment for 3D printing was conducted. A comparison and analysis of traditional methods and 3D printing for asphalt pavement maintenance led to an investigation of 3D asphalt printing technologies and equipment. As a result, the following suggestions and conclusions are proposed: 3D printing technology can increase the level of automation and standardization of pavement maintenance engineering, leading to effective improvements in worker safety, climate adaptability, repair accuracy, etc. For on-site repair of cracks and minor potholes, utilizing material extrusion technology a mobile 3D asphalt printing robot with a screw extrusion device can be used for accuracy and flexibility. For efficient repair of varying cracks, material jetting technology with a UAV equipped with a 3D printing air-feeding device can be employed

Promoting transparency through information : A global review of school report cards

The report examines the development of school report cards (SRCs) in selected countries around the world, with a particular emphasis on developing countries. It is intended to assist policy-makers and programme implementers in making informed decisions about how to use SRCs. The report includes: a review of the existing literature, interviews with 22 individuals at various levels of government covering different areas of responsibility connected with implementing countries, a descriptive summary of 14 countries, a summary of structures that can help review efforts undertaken to date, a set of newly developed indicators that integrate issues of accountability and anti-corruption effectiveness in the interpretation of SRCs, selected summaries and suggestions for improvement. The document builds on a USAID Working Paper developed in 2006 for the EQUIP 2 Project (Cameron, Moses, and Gillies, 2006) and examines cases in which report cards have proven especially successful in helping to improve transparency and accountability in education systems. It presents interview and survey findings from 14 countries where SRCs have been implemented in recent years, and compares their design and implementation. It gauges the settings for SRCs through an accountability and transparency index based on the authors’ observations, and examines whether and how SRCs can be used as part of the toolkit in the fight against corruption in the education sector. Finally, it proposes an implementation framework to help improve the delivery of education services and reduce corrupt practices. Some key highlights are: School report cards can be powerful tools to engage communities and hold schools accountable for providing students with a high-quality education. If the process is inclusive and participatory, SRCs can serve as a unique channel allowing education stakeholders to make more informed decisions based on school-level data. Reporting in SRCs appears to be more comprehensive than before. More comprehensive models include measuring outputs – a key factor in accountability – and parent perception. Most countries that appear to be less successful in SRC implementation lack a good understanding of SRC standards and what consequences can be expected based on SRC results. Most SRCs are missing clear, effective accountability measures, as well as clear links to those capable of making changes. More systematic efforts to employ SRCs to identify corruption often focus on specific areas, such as corruption in finance, teacher behaviour, and information systems. The exact relationship between implementation of SRCs and a country’s perceived level of education corruption is unclear. A number of countries with higher levels of perceived corruption in education are among those using more sophisticated SRC approaches. Accountability is a key element in the fight against corruption, and is led, in part, by transparency. Three case study areas, namely Indonesia, Brazil, and the state of Virginia in the United States, employ a combination of transparency and measurable consequences, which increase the accountability of schools

Phosphorylation of TGB1 by protein kinase CK2 promotes barley stripe mosaic virus movement in monocots and dicots.

The barley stripe mosaic virus (BSMV) triple gene block 1 (TGB1) protein is required for virus cell-to-cell movement. However, little information is available about how these activities are regulated by post-translational modifications. In this study, we showed that the BSMV Xinjiang strain TGB1 (XJTGB1) is phosphorylated in vivo and in vitro by protein kinase CK2 from barley and Nicotiana benthamiana. Liquid chromatography tandem mass spectrometry analysis and in vitro phosphorylation assays demonstrated that Thr-401 is the major phosphorylation site of the XJTGB1 protein, and suggested that a Thr-395 kinase docking site supports Thr-401 phosphorylation. Substitution of Thr-395 with alanine (T395A) only moderately impaired virus cell-to-cell movement and systemic infection. In contrast, the Thr-401 alanine (T401A) virus mutant was unable to systemically infect N. benthamiana but had only minor effects in monocot hosts. Substitution of Thr-395 or Thr-401 with aspartic acid interfered with monocot and dicot cell-to-cell movement and the plants failed to develop systemic infections. However, virus derivatives with single glutamic acid substitutions at Thr-395 and Thr-401 developed nearly normal systemic infections in the monocot hosts but were unable to infect N. benthamiana systemically, and none of the double mutants was able to infect dicot and monocot hosts. The mutant XJTGB1T395A/T401A weakened in vitro interactions between XJTGB1 and XJTGB3 proteins but had little effect on XJTGB1 RNA-binding ability. Taken together, our results support a critical role of CK2 phosphorylation in the movement of BSMV in monocots and dicots, and provide new insights into the roles of phosphorylation in TGB protein functions

Mixing state and particle hygroscopicity of organic-dominated aerosols over the Pearl River Delta region in China

Simultaneous measurements of aerosol hygroscopicity and particle-phase chemical composition were performed at a suburban site over the Pearl River Delta region in the late summer of 2016 using a self-assembled hygroscopic tandem differential mobility analyzer (HTDMA) and an Aerodyne quadruple aerosol chemical speciation monitor (ACSM), respectively. The hygroscopic growth factor (HGF) of the Aitken mode (30 nm, 60 nm) and accumulation mode (100 nm, 145 nm) particles were obtained under 90% relative humidity (RH). An external mixture was observed for particles of every size during this study, with a dominant mode of more-hygroscopic (MH) particles, as aged aerosols dominated due to the anthropogenic influence. The HGF of lesshygroscopic (LH) mode particles increased, while their number fractions decreased during the daytime due to a reduced degree of external mixing that probably resulted from the condensation of gaseous species. These LH mode particles in the early morning or late afternoon could be possibly dominated by carbonaceous material emitted from local automobile exhaust during rush hours. During polluted days with air masses flowing mainly from the coastal areas, the chemical composition of aerosols had a clear diurnal variation and a strong correlation with the mean HGF. Closure analysis was carried out between the HTDMA-measured HGF and the ACSM-derived hygroscopicity using various approximations for the hygroscopic growth factor of organic compounds (HGF(org)). Considering the assumptions regarding the differences in the mass fraction of each component between PM1 and 145 nm particles, the hygroscopicity-composition closure was achieved using an HGF(org) of 1.26 for the organic material in the 145 nm particles and a simple linear relationship between the HGForg and the oxidation level inferred from the O : C ratio of the organic material was suggested. Compared with the results from other environments, HGF(org) obtained from our measurements appeared to be less sensitive to the variation of its oxidation level, which is, however, similar to the observations in the urban atmosphere of other megacities in China. This finding suggests that the anthropogenic precursors or the photooxidation mechanisms might differ significantly between the suburban and urban atmosphere in China and those in other background environments. This may lead to different characteristics of the oxidation products in secondary organic aerosols (SOA) and therefore to a different relationship between the HGF(org) and its O : C ratio.Peer reviewe

Genetic Quantization-Aware Approximation for Non-Linear Operations in Transformers

Non-linear functions are prevalent in Transformers and their lightweight variants, incurring substantial and frequently underestimated hardware costs. Previous state-of-the-art works optimize these operations by piece-wise linear approximation and store the parameters in look-up tables (LUT), but most of them require unfriendly high-precision arithmetics such as FP/INT 32 and lack consideration of integer-only INT quantization. This paper proposed a genetic LUT-Approximation algorithm namely GQA-LUT that can automatically determine the parameters with quantization awareness. The results demonstrate that GQA-LUT achieves negligible degradation on the challenging semantic segmentation task for both vanilla and linear Transformer models. Besides, proposed GQA-LUT enables the employment of INT8-based LUT-Approximation that achieves an area savings of 81.3~81.7% and a power reduction of 79.3~80.2% compared to the high-precision FP/INT 32 alternatives. Code is available at https:// github.com/PingchengDong/GQA-LUT.Comment: 61st ACM/IEEE Design Automation Conference (DAC) 202

Transcriptomic and metabolic regulatory network characterization of drought responses in tobacco

Drought stress usually causes huge economic losses for tobacco industries. Drought stress exhibits multifaceted impacts on tobacco systems through inducing changes at different levels, such as physiological and chemical changes, changes of gene transcription and metabolic changes. Understanding how plants respond and adapt to drought stress helps generate engineered plants with enhanced drought resistance. In this study, we conducted multiple time point-related physiological, biochemical,transcriptomic and metabolic assays using K326 and its derived mutant 28 (M28) with contrasting drought tolerance. Through integrative analyses of transcriptome and metabolome,we observed dramatic changes of gene expression and metabolic profiles between M28 and K326 before and after drought treatment. we found that some of DEGs function as key enzymes responsible for ABA biosynthesis and metabolic pathway, thereby mitigating impairment of drought stress through ABA signaling dependent pathways. Four DEGs were involved in nitrogen metabolism, leading to synthesis of glutamate (Glu) starting from NO−3 /NO−2 that serves as an indicator for stress responses. Importantly, through regulatory network analyses, we detected several drought induced TFs that regulate expression of genes responsible for ABA biosynthesis through network, indicating direct and indirect involvement of TFs in drought responses in tobacco. Thus, our study sheds some mechanistic insights into how plant responding to drought stress through transcriptomic and metabolic changes in tobacco. It also provides some key TF or non-TF gene candidates for engineering manipulation for breeding new tobacco varieties with enhanced drought tolerance

Selectivity control in photocatalytic valorization of biomass-derived platform compounds by surface engineering of titanium oxide

化学化工学院王野教授课题组与程俊教授课题组合作，在生物质光催化选择转化方面取得重要突破。研究团队发展了一种调控TiO2表面结构以控制生物质转化途径的新方法，率先实现多种木质纤维素平台分子的光催化还原选择性调控，获得高产率的加氢产物(精细化学品)或偶联产物(燃料前驱体)。该论文第一作者为化学化工学院2015级博士毕业生吴雪娇、2015级博士毕业生李洁琼和固体表面物理化学国家重点实验室谢顺吉博士。【Abstract】Photocatalysis has offered a promising opportunity for selective transformation of biomass to high-value chemicals or fuels under mild conditions. Whereas titanium oxide has been widely used for photocatalytic pollutant degradation, H2 evolution, and CO2 reduction, few studies have been devoted to TiO2-based photocatalytic valorization of biomass or biomass-derived platform compounds. Here, we report on surface-controlled photocatalysis of TiO2 for selective valorization of furfurals and vanillin that are lignocellulose-derived key platform compounds. The reaction can be switched from hydrogenation of aldehyde group to C–C coupling by manipulating exposed facets; furanic and aromatic alcohols or coupling products, which are fine chemicals or jet-fuel precursors, could be produced with high selectivity. Our studies elucidate that the facet-dependent density of oxygen vacancies governs the charge distribution and adsorption strength of surface species and thus controls product selectivity. The present work offers an example of selectivity control by engineering TiO2 surfaces for valorization of biomass-derived feedstocks.This work was supported by the National Natural Science Foundation of China (nos. 21690082 and 21972115). 论文中相关研究工作得到国家自然科学基金(21690082、21972115)等项目的资助

Application of Nano PAC on Mitigating Membrane Fouling by Surface Properties Optimization

Membrane material has been widely accepted owing to the ability in water treatment, but the membrane fouling problem in using process is seriously restricted the promotion of membrane technology. So in this research nano PAC flocculant is added into the raw water to reach the goals of strengthening treatment efficiency and mitigating membrane fouling. According to the TMP change, it results that the PAC dosage of 45mg/L can realize the purpose to mitigate membrane fouling best. Compared with MBR, the MCBR is 16 days tardiness at the change of TMP, 1/3 gel layer filtration resistance less and 3.5% C element content fewer. The sum of C, O and N elements content, in addition, in the gel layer pollutants is more than 95%. That means membrane pollution is mainly caused by organic matter and nano PAC has the effect on surface properties optimization and membrane fouling mitigating