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In the last years, hot - stamped coating steel plates have been used to automobile lightweight parts widely to meet the increasingly stringent regulatory requirements for fuel consumption and greenhouse gas emissions while promoting passenger safety. Using metallographic microscope, scanning electron microscope (SEM) and salt spray test chamber, the coating morphology and corrosion performance of uncoated, hot - dip pure zinc coated and Al - Si coated hot - stamped steel plates were compared and investigated. Results showed that the metallographic structure of the three hot - stamped materials was mainly martensite with a small amount of retained austenite; the coatings of Al - Si coated and zinc coated hot - stamped steel plates were complete, and no cracks penetrating the base material were found; the decarburized layer depth of uncoated hot - stamped steel plate was about 10 μm, the Al - Si coating consisted of α - Fe, Fe2Al5, FeAl and Fe2Al5 layers, and the zinc coating was mainly composed of α - Fe phase; the time spans for occurring 5% red rust in neutral salt spray (NSS) environment for uncoated, Al - Si coated and zinc coated hot - stamped steel plates were 6, 76, 96 h, respectively, and the corrosion depth was 257, 134, 66 μm, respectively. Besides, in NSS environment, the corrosion width for uncoated, Al - Si coated and zinc coated hot - stamped steel plates with electrophoretic treatment was 75.6, 42.3, 143.8 μm and the corrosion depth was 32.2, 7.0, 2.5 μm, respectively. The corrosion resistance was zinc coated electrophoretic plate > Al - Si coated > uncoated plate in order.

Graphene nanoribbons (GNRs) are considered promising candidates for next‐generation nanoelectronics. In particular, GNR heterojunctions have received considerable attention due to their exotic topological electronic phases at the heterointerface. However, strategies for their precision synthesis remain at a nascent stage. Here, we report a novel chain‐growth polymerization strategy that allows for constructing GNR heterojunction with N=9 armchair and chevron GNRs segments (9‐AGNR/cGNR). The synthesis involves a controlled Suzuki–Miyaura catalyst‐transfer polymerization (SCTP) between 2‐(6′‐bromo‐4,4′′‐ditetradecyl‐[1,1′:2′,1′′‐terphenyl]‐3′‐yl) boronic ester (M1) and 2‐(7‐bromo‐9,12‐diphenyl‐10,11‐bis(4‐tetradecylphenyl)‐triphenylene‐2‐yl) boronic ester (M2), followed by the Scholl reaction of the obtained block copolymer (poly‐M1/M2) with controlled Mn (18 kDa) and narrow Đ (1.45). NMR and SEC analysis of poly‐M1/M2 confirm the successful block copolymerization. The solution‐mediated cyclodehydrogenation of poly‐M1/M2 toward 9‐AGNR/cGNR is unambiguously validated by FT‐IR, Raman, and UV/Vis spectroscopies. Moreover, we also demonstrate the on‐surface formation of pristine 9‐AGNR/cGNR from the unsubstituted copolymer precursor, which is unambiguously characterized by scanning tunneling microscopy (STM). [ABSTRACT FROM AUTHOR]

Graphene‐Nanostreifen (GNS, engl. GNR) werden als vielversprechende Kandidaten für Nanoelektroniken der nächsten Generation gehandelt. Besonders Heteroübergänge in diesen Materialien erhalten durch ihre exotischen topologischen elektronischen Phasen am Heteroübergang in letzter Zeit viel Aufmerksamkeit. Allerdings sind Synthesestrategien für die atompräzise Synthese noch am Beginn ihrer Entwicklung. Hier berichten wir von einer neuartigen Strategie zur Kettenwachstumspolymerisation für die Konstruktion von Heteroübergängen zwischen N=9 Sessel‐GNR (engl. armchair, 9‐AGNR) und chevron GNRs (cGNR). Die Synthese beinhaltet eine kontrollierte Suzuki–Miyaura Katalysatortransferpolymerisation (engl. SCTP) zwischen 2‐(6′‐bromo‐4,4′′‐ditetradecyl‐[1,1′:2′,1′′‐terphenyl]‐3′‐yl)boronsäureester (M1) und 2‐(7‐bromo‐9,12‐diphenyl‐10,11‐bis(4‐tetradecylphenyl)‐triphenylen‐2‐yl)boronsäureester (M2) um das Blockcopolymer poly‐M1/M2 mit einem kontrollierten Mn (18 kDa) und einem schmalen Polydispersitätsindex Đ (1.45) zu erhalten. Darauf folgt eine Schollreaktion des Blockcopolymers zur Heterostruktur 9‐AGNR/cGNR. NMR und SEC von poly‐M1/M2 bestätigen die erfolgreiche Blockcopolymerisation. Die lösungsvermittelte Zyklodehydrierung von poly‐M1/M2 zu 9‐AGNR/cGNR wurde eindeutig über FT‐IR, Raman und UV/Vis Spektroskopie nachgewiesen. Weiter konnten wir die Ausbildung von 9‐AGNR/cGNR durch Oberflächenchemie des unsubstituierten Blockcopolymers mit Hilfe von Rastertunnelmikroskopie (RTM) direkt visualisieren. [ABSTRACT FROM AUTHOR]

The precision synthesis of helical bilayer nanographenes (NGs) with new topology is of substantial interest because of their exotic physicochemical properties. However, helical bilayer NGs bearing non‐hexagonal rings remain synthetically challenging. Here we present the efficient synthesis of the first helical bilayer nonbenzenoid nanographene (HBNG1) from a tailor‐made azulene‐embedded precursor, which contains a novel [10]helicene backbone with two embedded heptagons. Single‐crystal X‐ray analysis reveals its highly twisted bilayer geometry with a record small interlayer distance of 3.2 Å among the reported helical bilayer NGs. Notably, the close interlayer distance between the two layers offers intramolecular through‐space conjugation as revealed by in situ spectroelectrochemistry studies together with DFT simulations. Furthermore, the chiroptical properties of the P/M enantiomers of HBNG1 are also evaluated by circular dichroism and circularly polarized luminescence. [ABSTRACT FROM AUTHOR]

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Structurally precision graphene nanoribbons (GNRs) have attracted great interest considering their prospective applications as organic carbon materials for nanoelectronics. The electronic properties of GNRs not only critically depend on the edge structure and width but also on the heteroatom type, doping position, and concentration. Motivated by the recent undisputable progress in the synthesis of stable boron‐doped polycyclic aromatic hydrocarbons (B‐PAHs), considerable efforts have been devoted to the precision synthesis of the corresponding boron‐doped GNRs (B‐GNRs) via bottom‐up synthesis approach in recent years in view of the extraordinary ability of boron doping on modulating their physiochemical properties. In this review, an overview of the bottom‐up organic synthesis of B‐GNRs, including the precursor design and synthesis, structure characterization of the resulting B‐GNRs, and investigation of their electronic properties is provided. Moreover, the future challenges and perspectives regarding the bottom‐up synthesis of B‐GNRs are also discussed. The authors hope that this review will further stimulate the synthesis and device integrations of B‐GNRs with a combined effort from different disciplines. [ABSTRACT FROM AUTHOR]

Herein, we demonstrate a novel one‐pot synthetic method towards a series of boron‐doped polycyclic aromatic hydrocarbons (B‐PAHs, 1 a–1 o), including hitherto unknown B‐doped zethrene derivatives, from ortho‐aryl substituted diarylalkynes with high atom efficiency and broad substrate scopes. A reaction mechanism is proposed based on the experimental investigation together with the theoretical calculations, which involves a unique 1,4‐boron migration process. The resultant benchtop‐stable B‐PAHs are thoroughly investigated by X‐ray crystallography, cyclic voltammetry, UV/Vis absorption, and fluorescence spectroscopies. The blue and green organic light‐emitting diode (OLED) devices based on 1 f and 1 k are further fabricated, demonstrating the promising application potential of B‐PAHs in organic optoelectronics. [ABSTRACT FROM AUTHOR]

NE China recorded the key tectonic evolution history of the Eurasian Plate from the Paleozoic-Mesozoic collisional formation of the Central Asian Orogenic Belt to the Mesozoic subduction of the Paleo-Pacific Ocean. To better understand this tectonic transition, it is crucial to constrain the time and pattern of the initial subduction of the Paleo-Pacific Ocean. Recently, some researchers proposed that the Mudanjiang Ocean existed between the Songnen and Jiamusi blocks was part of the Paleo-Pacific Ocean. Here, through geochemical and geochronological studies on the widespread granitoids in the Lesser Xing'an-Zhangguangcai Range in the eastern Songnen Block, we verify that these magmatic rocks show volcanic arc affinity with increased mantle contribution from east to the west of the range, likely related to a flattening subduction of the Mudanjiang Ocean. In addition, a universal westward younging trend for over 70 Myr can be observed for the granitoids throughout the Lesser Xing'an-Zhangguangcai Range, indicating a long-lasting subduction of the Mudanjiang Ocean. More interestingly, the oldest ages of the granitoids in the east display a northward younging trend from 275 Ma to 218 Ma, suggesting that the subduction of the Mudanjiang Ocean had been initiated at latest by 275 Ma in the south and then progressively expanded to the north. Based on these observations, we proposed a new tectonic evolution model for the Mudanjiang Ocean, i.e., a Triassic-Jurassic westward scissor-like subduction and closure, to contribute to the understanding of the early subduction of the Paleo-Pacific Ocean. [ABSTRACT FROM AUTHOR]

An integrated study on two subduction-related units (the Heilongjiang Complex and magmatic rocks in the Lesser Xing'an-Zhangguangcai Range) was carried out to explore the Paleozoic to early Mesozoic tectonic framework of the eastern Northeast China, with a focus on the Jiamusi block. The Heilongjiang Complex, which is considered as the suture between the Jiamusi and Songliao blocks, is composed of blueschist, amphibolite and ultramafic rocks. The blueschist from the Yilan area shows geochemical features similar to OIB and has a 206 Pb/ 238 U age of 288 ± 2 Ma, which is interpreted as the crystallization age of protolith formed in an ocean island setting. In contrast, amphibolite from the Xiachengzi area shows geochemical features similar to N-MORB. Zircons in this amphibolite show magmatic character and yield a 206 Pb/ 238 U age of 248 ± 4 Ma, which is interpreted as the protolith age. Calcic amphiboles in the amphibolite give a 40 Ar/ 39 Ar plateau age of 195 ± 3 Ma, which is interpreted as the metamorphic age of the Heilongjiang Complex. Magmatic rocks in the Lesser Xing'an-Zhangguangcai Range mostly belong to I-type granites that were formed in an active continental margin setting. Zircon U-Pb ages of these granites range from ~ 200 Ma to ~ 174 Ma with a westward younging trend shown as two groups of emplacing ages of ~ 200 Ma in the east and ~ 180 Ma in the west. Our new data support an early occurrence (likely since the early Permian) of a large ocean (namely the Mudanjiang Ocean) in the area, whose subduction resulted in the metamorphic unit (the Heilongjiang Complex) and the magmatic unit (the Lesser Xing'an-Zhangguangcai Range) in the Jurassic. [ABSTRACT FROM AUTHOR]

A metal-free visible-light-mediated decarboxylative acylation/ring expansion of vinylcyclobutanols with α-keto acids has been developed. Hypervalent iodine reagent was found to be important for promoting decarboxylation of α-keto acids in this tandem radical process. This protocol has been successfully applied to synthesis of a variety of substituted 1,4-dicarbonyl compounds and tolerated some functional groups well. [ABSTRACT FROM AUTHOR]

In this paper, an optimization model is developed for co-ordinately scheduling electricity and heat production within a microgrid. The model achieves the minimization of total operating cost including electricity and fuel consumption with various operational constraints considered. Comparative research between the mathematical method of mixed-integer programming (MIP) and meta-heuristic technique of improved particle swarm optimization (IPSO) for solving this model is implemented. Simulation results for the scheduling problem with different sizes and different operational constraints show that the solution precision achieved by IPSO and MIP is very similar, IPSO is much less time-consuming than MIP for the large-scale scheduling problem when the non-linear constraints of power flow within the microgrid are considered and the situation is the opposite when power flow constraints are not considered. [ABSTRACT FROM AUTHOR]