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A series of aromatic sulfonic acids is synthesized by subjecting arenes and NaHSO4·H2O to high-speed ball milling in the presence of P2O5. It is suggested the aromatic sulfonation occurs via in situ generated H2SO4 to give aromatic sulfonic acids. In some cases, formation of diaryl sulfones was observed.

Although the individual one- and two-dimensional (1D and 2D) carbon nanostructures possess extremely high thermal conductivity, their macroscopic assemblies do not efficiently utilize it due to the larger interfacial contact thermal resistance. To improve the overall performance, the key is the interfacial structure design to provide sufficient pathways for phonon transport with a limited sacrifice or damage to the inherent thermal properties of nanomaterials. Particularly, the resonance of low-frequency lattice vibrations is the most important mechanism for the reduction of the interfacial contact thermal resistance. Based on recent theoretical and experimental studies and observations on interfacial heat transport, we review here a fourfold set of transport problems in this field: (1) low-frequency phonons in 1D and 2D nanostructures for heat transport; (2) the mechanisms of interfacial thermal transport; (3) assembly structure design towards high utilization of the thermal conductivity from individual nanostructures; and (4) recent development of thermal conductivity measurement for individual and assembled nanomaterials.

The quantum anomalous Hall (QAH) effect has attracted enormous attention since it can induce topologically protected conducting edge states in an intrinsic insulating material. For practical quantu...

The quantum anomalous Hall (QAH) effect has been experimentally observed in magnetically-doped topological insulators. However, the QAH effect is only seen at extremely low temperatures due to the weak magnetic coupling, small band gap and low carrier mobility. Here, based on first-principles density functional theory, we predict that the Janus Mn2X3Y3 (X, Y) = F, Cl, Br, I are high Curie temperature ferromagnets. Furthermore, we find that they are Dirac half-metals characterized by a Dirac cone in one spin channel with carrier mobilities comparable to freestanding germanene and a large band gap in the other spin channel except for Mn2F3I3. Simultaneously, when the spin-orbital coupling interaction is considered, the Janus Mn2F3Cl3, Mn2Cl3Br3, and Mn2Br3I3 exhibit a nontrivial band gap, indicating that they host a QAH phase. More interestingly, both the Chern number sign and the chiral edge current are tuned by changing the direction of magnetization. Moreover, we find that topological properties are related to the lattice constant and magnetocrystalline anisotropy. Our findings would suggest the possibility of not only realizing the QAH effect but also designing the flow direction of the edge current.

Probiotics have been widely used in aquaculture. This article aims to study the effect of Bacillus amyloliquefaciens LSG2-8 on the intestinal barrier function of Rhynchocypris lagowskii. B. amyloliquefaciens LSG2-8 were added to R. lagowskii basal diets (CK) as additives at four concentrations: 1.0 × 106 (D−6), 1.0 × 107 (D−7), 1.0 × 108 (D−8) and 1.0 × 109 (D−9) CFU/g by dry weight of basal diet. After a 56 days feeding experiment, the intestinal digestive enzymes and immune enzymes activity of R. lagowski on group D-6, D-7, D-8 and D-9 diet were significantly higher than the control (p R.. lagowskii were significantly higher (p R. lagowski on group D-6, D-7, D-8 and D-9 diet were significantly lower than the control (p B. amyloliquefaciens LSG2-8 can regulate the intestinal flora balance and improve the intestinal structure of R. lagowskii. In conclusion, B. amyloliquefaciens LSG2-8 can improve the intestinal barrier function of R. lagowskii,and can be used as a feed additive in aquaculture.

To study the effects of dietary methionine on growth performance, immunity, antioxidant capacity, protein metabolism, inflammatory response and apoptosis factors in Chinese mitten crabs (Eriocheir sinensis). Five diets with different methionine levels (0.63%, 0.85%, 1.06%, 1.25% and 1.47%) were fed to E. sinensis for 8 weeks. Results showed that in the 1.25% Met group, both growth performance and feed utilization were significantly increased. The crude protein content of crab muscle in the 1.06% and 1.25% Met groups was significantly higher than that in the control group. The immune and antioxidant enzyme activities, as well as gene expression levels of anti-lipopolysaccharide factor 1 (ALF1), Crustin-1, prophenoloxidase (proPO), cap 'n' collar isoform C (CncC) in 1.25% Met group were significantly higher than other groups. The activities of adenosine deaminase (ADA) and glutamate transaminase (GPT) in serum decreased first and then increased with the increase of methionine content, while the changes of ADA and GPT in hepatopancreas increased first and then decreased. 1.25% Met group exhibited significantly increased levels of GOT, GPT, and ADA compared to the control group. 1.25% Met diet group significantly up-regulated protein synthesis and anti-apoptotic factors, and significantly down-regulated inflammatory and pro-apoptotic factors in hepatopancreas. At 1.25% in the diet, methionine was found to boost E. sinensis growth, muscle protein deposition and immunity, as well as its antioxidant capacity. Combined with the above results, based on the expression of factors involved in the mammalian target of rapamycin (mTOR) signaling pathway and the mitogen-activated protein kinase (MAPK) signaling pathway, it is proved that methionine can not only promote protein metabolism, improve feed utilization, but also alleviate the inflammatory response and apoptosis caused by oxidative stress in the body.

Deoxygenative chlorination of carbonyl compounds using the HMe2SiCl/FeCl3/EtOAc and HMeSiCl2/FeCl3/EtOAc systems has been systemically investigated. The HMe2SiCl-FeCl3 system showed the advantages of good substrate applicability, mild reaction conditions, simple operation, low cost, and easy availability of raw materials. Also, it provided a simple and efficient synthesis route for carbonyl deoxychlorination via a one-pot method. Using the HMeSiCl2/FeCl3/EtOAc system, the β-methylchalcone derivative could be obtained in good yields in addition to obtaining the chlorinated compound. Finally, two plausible reaction routes were proposed to describe the formation of the chlorinated compound and the β-methylchalcone derivative.

This study evaluated the effects of dietary administration of two indigenous Bacillus (A: basal control diet; B: 0.15 g/kg of Bacillus subtilis; C: 0.1 g/kg of Bacillus subtilis and 0.05 g/kg of Bacillus licheniformis; D: 0.05 g/kg of Bacillus subtilis and 0.1 g/kg of Bacillus licheniformis; E: 0.15 g/kg of Bacillus licheniformis) on the digestive enzyme activities, intestinal morphology, intestinal immune and barrier-related genes relative expression levels, and intestinal flora of Rhynchocypris lagowskii. The results showed that the fold height, lamina propria width, and muscle layer thickness of midgut and hindgut in group C were significantly higher than that of group A (P 0.05). The activities of protease, amylase, and lipase in group C were significantly higher than those of group A (P 0.05). The relative expression levels of IL-1β and IL-8 in the intestine of group C were significantly downregulated, and the relative expression levels of IL-10 and TGF-β were significantly upregulated (P 0.05). The relative expression levels of Claudin-2 in group A significantly increased and the relative expression levels of Claudin-4 in group A significantly reduced compared with other groups (P 0.05). The relative expression levels of ZO-1 in groups C and D were significantly higher than those of other groups (P 0.05). The Bacillus in the intestine of group C has the highest relative abundance among all groups. Overall, it can generally be concluded that dietary supplementation of indigenous Bacillus subtilis and Bacillus licheniformis (group C) can improve the intestinal morphology, digestion, and absorption enzyme activities, enhance intestinal mucosal immunity and barrier function, and maintain the intestinal microbial balance of R. lagowskii.

Two-dimensional (2D) semiconductors have attracted tremendous interest as natural passivation and atomically thin channels could facilitate continued transistor scaling. However, air-stable 2D semiconductors with high performance are quite elusive. Recently, an extremely-air-stable ${\mathrm{Mo}\mathrm{Si}}_{2}{\mathrm{N}}_{4}$ monolayer was successfully fabricated [Hong et al., Science 369, 670 (2020)]. To further reveal its potential application in sub-5-nm metal-oxide-semiconductor field-effect transistors (MOSFETs), there is an urgent need to develop integrated circuits. Here, we report first-principles quantum-transport simulations on the performance limits of n- and p-type sub-5-nm monolayer (ML) ${\mathrm{Mo}\mathrm{Si}}_{2}{\mathrm{N}}_{4}$ MOSFETs. We find that the on-state current in the ${\mathrm{Mo}\mathrm{Si}}_{2}{\mathrm{N}}_{4}$ MOSFETs can be effectively manipulated by the length of gate and underlap, as well as the doping concentration. Very strikingly, we also find that for the n-type devices the optimized on-state currents can reach up to 1390 and 1025 \textmu{}A/\textmu{}m for high-performance and low-power (LP) applications, respectively, both of which satisfy the International Technology Roadmap for Semiconductors (ITRS) requirements. The optimized on-state current can meet the LP application (348 \textmu{}A/\textmu{}m) for p-type devices. Finally, we find that the ${\mathrm{Mo}\mathrm{Si}}_{2}{\mathrm{N}}_{4}$ MOSFETs have an ultralow subthreshold swing and power-delay product, which have the potential to realize high-speed and low-power consumption devices. Our results show that ${\mathrm{Mo}\mathrm{Si}}_{2}{\mathrm{N}}_{4}$ is an ideal 2D channel material for future competitive ultrascaled devices.

It is conventionally believed that lattice thermal conductivity ( κ) decreases with increasing atomic mass (negative atomic-mass correlation), and the high κ can only occur in crystals composed of strongly bonded light elements. By solving the fundamental thermal conductivity equation using first-principles calculations, here we reveal the anomalous κ departing from the long-held concept, that is, a positive atomic-mass correlation and high κ with heavy elements and weakly bonded interaction. We demonstrate this anomalous phenomenon by performing calculations of the cross-plane κ of the layered compounds, i.e., the h-BX family with X = N, P, and As. We find that the anomalous increase in the cross-plane κ with X going from N to As results in the cross-plane/in-plane conductivity ratio, generally expected to be much smaller than 1 in layered compounds, reaching as large as 2.6 at low temperatures. We also find that the unusually high cross-plane κ (660 W m−1 K−1), which is comparable to the bulk silicon with strong covalent bonding interactions, can be generated by a weak van der Waals interaction. Our analysis shows that the anomalous κ arises from one-dimensional-like phonons propagating in the cross-plane direction, which is due to the extremely large phonon anisotropy induced by the combined effect of atomic-mass difference and structural anisotropy. This discovery paves an avenue to realize thermally conductive materials that have weakly bonded structures, which can be potentially applied in the design of high-performance nanoelectronic devices.

The quantum anomalous Hall (QAH) effect has been experimentally observed in magnetically-doped topological insulators. However, the QAH effect is only seen at extremely low temperatures due to the weak magnetic coupling, small band gap and low carrier mobility. Here, based on first-principles density functional theory, we predict that the Janus Mn

The Erlian Basin is one of the largest intracontinental Meso-Cenozoic basins in Northeast China. The basin is filled with extra-thick Cretaceous sediments and offers unique opportunities to untangle the Late Mesozoic intraplate deformation in East Asia. However, despite decades of petroleum exploration in the basin, the Early Cretaceous chronostratigraphy and structural evolution of the Erlian Basin have been poorly studied. Based on newly obtained zircon U-Pb geochronological data, well lithological logs, and seismic reflection profiles, the present study carries out a detailed analysis of the tectonostratigraphic evolution of the Erlian Basin during the Early Cretaceous. The depositional ages of the Lower Cretaceous strata in the basin are refined, and the Early Cretaceous evolution of the basin is reestablished. The Lower Aershan, Upper Aershan, Lower Tenggeer, Upper Tenggeer, and Saihan formations are constrained to the middle Valanginian (ca. 138–135 Ma), late Valanginian (ca. 135–133 Ma), Hauterivian–early Aptian (ca. 133–121 Ma), middle Aptian (ca. 119–115 Ma), and latest Aptian–Albian (post ca. 115 Ma), respectively. The Early Cretaceous syn-rift subsidence of the basin was intermittent rather than continuous, and was punctuated by multiphase contractional deformation during the earliest Cretaceous (prior to ca. 138 Ma), middle Valanginian (ca. 135 Ma), latest Valanginian (ca. 133 Ma), middle Aptian (ca. 120 Ma), late Aptian (ca. 115 Ma), and Early/Late Cretaceous boundary. We tentatively attribute the extensional and contractional deformation in the Erlian Basin to a series of continental collisions along Asian margins: Karakoram-Lhasa/Qiangtang collision, Kolyma-Omolon/Siberia collision, Siberia/Amuria collision, Chukotka/Kolyma-Omolon collision, West Philippines/South China collision, and Okhotomorsk/East Asia collision.

Acetophenones with a variety of substituents could be converted to diacylfuroxans in a solvent-free reaction by combining the reagents Fe(NO3)3·9H2O and P2O5 under high-speed ball milling. This reaction was facile and eco-friendly, and exhibits advantages in terms of better toleration, safety, and easier operation. The nitrate acid and nitrogen dioxide generated in situ should play a major role in this mechanochemical reaction.

Chemically functionalized carbon nanotubes were combined with PVC to enhance both toughness and strength by simply mixing long alkyl chain modified multi-wall carbon nanotubes (abbreviated as MWNTs) or Ester-functionalized soluble MWNTs (abbreviated as eMWNTs) with PVC in Tetrahydrofuran (THF)/Cyclohexanone (CH) solution to obtain good dispersity solution. The MWNTs modified with 1-Bromohexadecane can effectively increase the intermolecular force with PVC by hydrogen bond. The obtained nanocomposite has a regular shape with homogeneously dispersed particles. PVC/2 wt% eMWNTs has been proved to possess excellent thermal stability. The intermolecular force between eMWNTs and PVC endows the as-fabricated nanocomposite with enhanced toughness and strength, indicating that our method is promising for wide use in PVC/eMWNTs nanocomposition.

We have studied the effects of atomic mass (AM) and interatomic potential (IP) on the interface thermal transport of graphene-based intralayer heterostructures, composed of graphene (Gr) and graphene-like materials (Gx). We find that the phonon mismatch between Gx and Gr, induced by the variations of both AM and IP, leads to an obvious thermal resistance in such a hybrid heterostructure model device, following some scaling laws. Compared with that of graphene, the Kapitza resistance (R) of the hybrid heterostructure increases linearly (in power law) with the decrease (increase) of AM in Gx, whereas its variation with IP presents a contrary behavior. On the other hand, the effective interface thermal resistivity (r) increases parabolically (exponentially) with decreasing (increasing) AM and IP in Gx. We also find that the thermal rectification ratio can be effectively manipulated by the variation of AM and IP. Finally, we illustrate that the obtained scaling laws can be used to estimate r in real heterostructures. This study is expected to provide an efficient way to evaluate the interface effect on thermal transport, which have potential applications in design of high-performance heterostructure-based nanodevices.

In this paper, one-step preparation of graphene/gold nanoparticle hydrogel film through the hydrothermal method is reported. The hydrogel film could be formed on a glass substrate under hydrothermal conditions, and upon freeze-drying, the aerogel film of 40 μm thickness with satisfying flexibility and strength is obtained. The aerogel composite film is characterized by scanning/transmission electron microscopy, X-ray diffraction, Raman spectroscopy and X-ray photoelectron spectroscopy. Moreover, the aerogel film is directly used as the electrochemical electrode for sensing H2O2, and exhibits good performance with a broad linear range, low detection limit and excellent selectivity. This work provides a route for the fabrication of graphene film material with wide potential in various aspects.

The optical absorption properties of carbon nanotubes (CNTs) have attracted extensive research attention. Here we report the fabrication of sea-island structured polymer-based multi-walled CNT (MWNT) composite with high solar-thermal-conversion performance. MWNT-grafted 4-chloromethyl styrene (MWNTs-g-CMS) is prepared via esterification between carboxyl groups on the MWNT surface and the chloromethyl group of the CMS in the presence of a phase-transfer reagent in water. Covalent bonding between the CMS and the MWNTs is confirmed by Fourier transform infrared spectra. Thermogravimetric analysis of the MWNTs-g-CMS shows a mass percentage of the attached methyl styrene chains as high as 24.31 wt%. Subsequently, polymer-based MWNT-graft-polyvinyl-chloride (MWNTs-g-PVC) composite was prepared via an in-situ graft polymerization between the vinyl chloride and active styryl groups of the MWNTs-g-CMS. The MWNT grafting efficiencies in a series of MWNTs-g-PVC composites are 0.013–0.103%. The sea-island structure of the MWNTs-g-PVC composites and the fine dispersion of MWNTs in the island are verified by electron microscopy. The solar-thermal conversion performance of the MWNTs-g-PVC composites is studied. The composites exhibit excellent light-absorption properties that resemble a black body, and yield a higher solar-thermal conversion efficiency than the carboxylic MWNT (PVC/MWNTs-COOH) composites, which is attributed to the sea-island structure and the good dispersion of MWNTs in the islands.

A facile method for oxidation of primary benzylic alcohols to the corresponding aldehydes is reported using NaNO3/P2O5 under high-speed ball-milling conditions. This approach is clean, efficient, and exhibits broad functional group compatibility.

The recent discovery of two-dimensional (2D) magnetic materials which are compound of transition metal (TM) with other elements, has opened new avenues for basic research on low-dimensional magnetism and potential applications in spintronics. To further explore new 2D magnets of pure TM is thus of an interesting topic. Based on the first-principles calculations, here we propose a strategy of obtaining monolayer TM magnets, i.e., depositing TM atoms on graphyne (Gy) which has proper hexagonal hollow geometry. We find that TM monolayer with perfect hexagonal geometry can be formed on Gy. The TM monolayer exhibits a wealth of physical properties in dependence of TM species, such as ferromagnetic and antiferromagnetic ground states, as well as intriguing semimetal and half-metal characteristics. We also find that the half-metal characteristics makes the monolayer TM have great potential applications in the horizontal magnetic tunnel junction (MTJ) devices, where the tunneling magnetoresistance can reach as high as 850000%. Our results provide a new framework for obtaining 2D magnets with outstanding spintronic properties., Comment: 16 pages, 5 figures

In this letter, we report the preparation of graphene-based aerogel decorated with gold nanoparticles under a mild condition and though a freeze-drying process. The porous composite aerogel is characterized by scanning/transmission electron microscopy, X-ray photoelectron spectroscopy, X-ray diffraction and Raman spectroscopy. The aerogel piece could be used directly as electrochemical sensor, different from the traditional modification of the glassy carbon electrode with the graphene. The aerogel electrode demonstrates satisfying electrocatalytic performances in the detection of H2O2 with good repeatability, fast response and low detection limit. This work would propose novel strategy for the applications of graphene in the fields of electroanalysis and sensing.

The Erlian Basin is an important part of the late Mesozoic extensional basin system in Northeast Asia. The basin contains thick Jurassic–Lower Cretaceous rocks and provides excellent opportunities to understand intracontinental deformation in Northeast Asia during the late Mesozoic. However, the Jurassic–Early Cretaceous evolution of the basin and associated driving mechanisms remain disputed. Based on 13 new zircon U-Pb ages for the Jurassic–lowest Cretaceous strata in the Erlian Basin, the correlation of Jurassic–lowest Cretaceous strata between the Erlian Basin and the Yan Shan is reestablished and a high-precision chronostratigraphic framework is presented. The Aqitu–Qiha formations are ascribed to the Aalenian–early Bathonian (ca. 174–167 Ma), the Xing'anling Group to the Oxfordian–early Kimmeridgian (ca. 163–153 Ma), the Hugejiletu Formation to the Tithonian–early Valanginian (ca. 151–139 Ma), and the Aershan Formation to the Valanginian–? (≤ca. 138 Ma). Combined with seismic reflection profiles, the Jurassic–earliest Cretaceous tectonostratigraphic evolution of the Erlian Basin is reconstructed and five major phases of deformation are revealed. These deformation phases include Aalenian–early Bathonian initial extension, late Bathonian–Callovian compression, Oxfordian–early Kimmeridgian extension, late Kimmeridgian–earliest Valanginian compression, and Valanginian extension. Integrated with geological evidences from peripheral regions of the Erlian Basin, potential driving mechanisms related to far-field tectonic events along Asian margins are suggested for each of these deformation phases.

The mechanochemical reaction of C60 and Bi(NO3)3·5H2O was performed under ball-milling condition. The product was well characterized by spectroscopic methods such as IR, Raman, UV-vis, 13C NMR, as well as elemental analysis method. The spectroscopic investigation indicates that some hydroxyl and nitro groups are attached to the C60 and no profound structural changes occur for the C60 cage in the product. The elemental analysis gives an average composition of C60(NO2)2(OH)21 for the product. A possible mechanism is suggested for the reaction.

We systematically study thermal conductivity of multilayer silicene by means of Boltzmann Transportation Equation (BTE) method. We find that their thermal conductivity strongly depends on the surface structures. Thermal conductivity of bilayer silicene varies from 3.31 W/mK to 57.9 W/mK with different surface structures. Also, the 2 × 1 surface reconstruction induces unusual large thermal conductivity anisotropy, which reaches 70% in a four-layer silicene. We also find that the anisotropy decreases with silicene thickness increasing, owing to the significant reduction of thermal conductivity in the zigzag direction and its slight increment in the armchair direction. Finally, we find that both the phonon-lifetime anisotropy and the phonon-group-velocity anisotropy contribute to the thermal conductivity anisotropy of multilayer silicene. These findings could be helpful in the field of heat management, thermoelectric applications involving silicene and other multilayer nanomaterials with surface reconstructions in the future.

A significant transition in tectonic regime from extension to compression occurred throughout East Asia during the mid-Cretaceous and has stimulated much attention. However, the timing and driving mechanisms of the transition remain disputed. The Erlian Basin, a giant late Mesozoic intracontinental petroliferous basin located in the Inner Mongolia, Northeast China, contains important sedimentary and structural records related to the mid-Cretaceous compressional event. The stratigraphical, sedimentological and structural analyses reveal that a NW–SE compressional inversion occurred in the Erlian Basin between the depositions of the Lower Cretaceous Saihan and Upper Cretaceous Erlian formations, causing intense folding of the Saihan Formation and underlying strata, and the northwestward migration of the depocenters of the Erlian Formation. Based on the newly obtained detrital zircon U-Pb data and previously published paleomagnetism- and fossil-based ages, the Saihan and Erlian formations are suggested as latest Aptian–Albian and post-early Cenomanian in age, respectively, implying that the inversion in the Erlian Basin occurred in the early Late Cretaceous (Cenomanian time). Apatite fission-track thermochronological data record an early Late Cretaceous cooling/exhuming event in the basin, corresponding well with the aforementioned sedimentary, structural and chronological analyses. Combining with the tectono-sedimentary evolutions of the neighboring basins of the Erlian Basin, we suggest that the early Late Cretaceous inversional event in the Erlian Basin and the large scale tectonic transition in East Asia shared the common driving mechanism, probably resulting from the Okhotomorsk Block–East Asia collisional event at about 100–89 Ma.

Three 2-phenyl-1,3-diazaazulene derivatives were synthesized and their protonation behaviours were investigated systematically via UV–vis absorption titration and 1H NMR titration, as well as theoretical calculations. One of them exhibited a monoprotonation process while the others displayed prominent halochromic diprotonation responses. Interestingly, upon protonation of 2-phenyl-1,3-diazaazulene derivatives, the coplanarity and conjugation of the 16-π-conjugated backbones were well kept, while the electronic structures were controllably adjusted. The response mechanism of 1,3-diazaazulene derivatives towards acid is through the attachment of acid proton to the nitrogen atom in the diazaazulene ring, resulting in the change of the hybridization of protonated-N from sp2 to sp3, which differed from that of the well-known azulene (analogue of 1,3-diazaazulene, protonation at carbon atom). This work would provide a new insight into the protonation research of the organic functional molecules.

A dimerized 1,3-diazaazulene derivative, namely 1,4-bis(1,3-diazaazulen-2-yl)benzene [or 2,2′-(1,4-phenylene)bis(1,3-diazaazulene)], C22H14N4, (I), has been synthesized successfully through the condensation reaction between 2-methoxytropone and benzene-1,4-dicarboximidamide hydrochloride, and was characterized by 1H NMR and 13C NMR spectroscopies, and ESI–MS. X-ray diffraction analysis reveals that (I) has a nearly planar structure with good π-electron delocalization, indicating that it might serve as a π building block. The crystal belongs to the monoclinic system. One-dimensional chains were formed along the a axis through π–π interactions and adjacent chains are stabilized by C—H...N interactions, forming a three-dimensional architecture. The solid emission of (I) in the crystalline form exhibited a 170 nm red shift compared with that in the solution state. The observed optical bandgap for (I) is 3.22 eV and a cyclic voltammetry experiment confirmed the energy levels of the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO). The calculated bandgap for (I) is 3.37 eV, which is very close to the experimental result. In addition, the polarizability and hyperpolarizability of (I) were appraised for its further application in second-order nonlinear optical materials.

The photovoltaic performance of organic-inorganic hybrid perovskite solar cells has reached a bottleneck after rapid development in last few years. Further breakthrough in this field requires deeper understanding of the underlying mechanism of the photoelectric conversion process in the device, especially the dynamics of charge-carrier recombination. Originating from dye-sensitized solar cells (DSSCs), mesoporous-structured perovskite solar cells (MPSCs) have shown many similarities to DSSCs with respect to their photoelectric dynamics. Herein, by applying the multiple-trapping model of the charge-recombination dynamic process for DSSCs in MPSCs, with rational modification, a novel physical model is proposed to describe the dynamics of charge recombination in MPSCs that exhibits good agreement with experimental data. Accordingly, the perovskite- and TiO2 -dominating charge-recombination processes are assigned and their relationships with the trap-state distribution are also discussed. An optimal balance between these two dynamic processes is required to improve the performance of mesoporous-structured perovskite devices.

The utilization of graphene-based aerogels in electrochemical analysis is a promising potential of this unique material. So far, most related works use the aerogels as the modifiers of the conventional electrodes. We report here the fabrication of graphene-based aerogel decorated with gold nanoparticles through a simple cast-freeze-drying process and the direct use of the aerogel composite piece as electrode in the detection of H 2 O 2 . The as-prepared aerogel composites are characterized by scanning electron microscopy, X-ray photoelectron spectroscopy, X-ray diffraction and Raman spectroscopy. The aerogel electrode acting as the H 2 O 2 sensor shows satisfying electrocatalytic performances, including fast response, low detection limit and good stability.

The Mohe-Upper Amur Basin to the south of the eastern Mongol-Okhotsk Suture Zone contains important stratigraphic records for understanding the closure of the eastern Mongol-Okhotsk Ocean. The basin is crossed by the Russia/China border, and its Chinese and Russian parts are known as the Mohe Basin and Upper Amur Basin, respectively. Using most up-to-date data on stratigraphy, sedimentology, petrography, and detrital zircon U-Pb geochronology, this study establishes the stratigraphic correlation between the two, Mohe and Upper Amur parts of the basin, and analyzes depositional ages, provenance, and paleogeography of their Jurassic–Lower Cretaceous strata. The adopted Middle–Late Jurassic ages for the Xiufeng, Ershierzhan, Emuerhe, and Kaikukang formations in the Mohe Basin, are revised and constrained to late Kimmeridgian, Tithonian, Berriasian–early Valanginian, and late Valanginian ages, respectively. During the late Kimmeridgian–Tithonian, extension occurred in the Mohe-Upper Amur Basin, and sediments were mainly sourced from areas to the south of the basin. Later, in the Berriasian–early Valanginian, the northern margin of the Mohe-Upper Amur Basin was uplifted and started furnishing sediments into the basin. In the late Valanginian, regional uplift of the northern part of the Mohe-Upper Amur Basin transformed the basin into a compressional intermountain basin, with sedimentation localized in its southern part. After the Valanginian, extension and associated volcanism occurred in the basin. We suggest that the evolution of the Mohe-Upper Amur Basin reflects the gradual closure of the eastern Mongol-Okhotsk Ocean and associated collision of the Siberia Craton and the Amuria Block, that occurred from the Kimmeridgian–Tithonian, to the west of the basin through to the Berriasian–Valanginian, to the north and northeast of the basin. The final closure of the Mongol-Okhotsk Ocean to the north of the Mohe-Upper Amur Basin in the earliest Cretaceous significantly affected the sedimentological, structural and tectonic evolution of Northeast Asia.

The hydrosilylation reduction of aldehydes and ketones to the corresponding alcohols with polymethylhydrosiloxane (PMHS) as hydrosilanes in the presence of potassium carbonate (K2CO3) has been developed. This Lewis base protocol displays excellent chemoselectivity and can tolerate a number of other reducible functionalities like nitro, sulfone, cyano, alkene, as well as ester. In order to make the mechanism of PMHS based hydrosilylation more clearly, we have isolated the silyl ether intermediates. We find that the PMHS is redistributed into methylsilane (H3SiMe) and a series of siloxanes in the structures of H2SiMeO(SiHMeO)nSiMeH2 (n=0, 1, 2,……), which serve as the active hydrosilanes for the hydrosilylation reaction.

Mesozoic basins in different regions of Central Asia provide important records for investigating relationships between intraplate deformation in Central Asia and tectonic processes at Asian boundaries. The present study gives a review of the stratigraphic and structural evolution of basins in different regions of Central Asia during the Middle-Late Jurassic. It is shown that basins and mountain belts in northwest China experienced compressional deformation and were wholly or partially uplifted during the late Middle-Late Jurassic. Compared to extensively-distributed Middle Jurassic coal-bearing strata in northwest China, Upper Jurassic strata characterized by red mudstones and conglomerates have a much smaller distribution. In the mean time, the Tibet-Pamir plateau also underwent a folding and uplift event, and Upper Jurassic sedimentary rocks are generally missing in the Pamir and western Tibet. The intense compressional deformation and uplift event of the late Middle-Late Jurassic from the Tibet-Pamir plateau to northwest China requires a new tectonic model, as proposed here. We suggest that the Karakoram and Lhasa blocks were a single giant block, which was accreted to Asia in the late Middle Jurassic-earliest Cretaceous and cross-cut by the Karakoram Fault in the Cenozoic. During the Callovian, the western part of the Karakoram-Lhasa Block initially collided with the southern Asian margin. Collision and continued convergence during the late Middle-Late Jurassic caused sinistral strike-slip faulting along the Central Badakhshan Fault and South Tian Shan Suture, accommodating crustal shortening in areas to the southeast of the faults: the Pamir, western Tibet, Tarim Block, Qilian-Qaidam Block, and Bei Shan. Meanwhile, the northeastward transpressional motion of the Tarim Block produced strong compressional stresses to areas north of the Tarim Block: the Kyrgyz Tian Shan, Central Tian Shan, Junggar Basin, and Turfan Basin. With the northward movement of the Karakoram-Lhasa Block, the eastern part of the Karakoram-Lhasa Block began to collide with the southern Asian margin during the latest Jurassic-earliest Cretaceous, resulting in strong crustal deformation and thickening in East Asia and Central Asia.

Organic-inorganic halide perovskite solar cell has surged a great wave in photovoltaic field owing to its rapid advances, in which CH₃NH₃PbI₃ as the most conventional active layer has been attracting great attention. Generally, in a CH₃NH₃PbI₃ layer, the unreacted PbI₂ inevitably coexists with the perovskite crystals, especially in the two-step fabrication process. There seems a consensus that appropriate amount of unreacted PbI₂ is beneficial to the overall photovoltaic performance of the device, while as for the disadvantageous aspect of excessively remained PbI₂, it stays at regarding PbI₂ as an insulator. Further investigation and advisable control of the component in perovskite crystal call for a deeper understanding of the remnant PbI₂. In this work, PbI₂-enriched and PbI₂-controlled perovskite films as two extremes are prepared by modulating the crystallinity of the pre-deposited PbI₂ film, and the effects of excessively remained PbI₂ are elucidated on the basis of spectroscopic and optoelectronic studies. The initial charge separation, trap state density and trap state distribution properties are all found to be adverse for the PbI₂-enriched devices, i.e., to deteriorate the photovoltaic performances. Complementarily, the biphasic recombination process is reproduced and the charge carrier recombination dynamics was accelerated owing to the excessively remained PbI₂.

Realizing topological Dirac states in two-dimensional (2D) magnetic materials is particularly important to spintronics. Here, we propose that such states can be obtained in a transition-metal (Hf) monolayer grown on a 2D substrate with hexagonal hollow geometry (graphyne). We find that the significant orbital hybridizations between Hf and C atoms can induce sizable magnetism and bring three Dirac cones at/around each high-symmetry K(K′) point in the Brillouin zone. One Dirac cone is formed by pure spin-up electrons from the dz2 orbital of Hf, and the remaining two are formed by crossover between spin-up electrons from the dz2 orbital and spin-down electrons from the hybridization of the dxy/x2−y2 orbitals of Hf atoms and the pz orbital of C atoms. We also find that the spin–orbit coupling effect can open sizable band gaps for the Dirac cones. The Berry curvature calculations further show the nontrivial topological nature of the system with a negative Chern number C = −3, which is mainly attributed to the Dirac states. Molecular dynamics simulations confirm the system's thermodynamic stability approaching room temperature. The results provide a new avenue for realizing the high-temperature quantum anomalous Hall effect based on 2D transition-metals.

In this paper, one-step preparation of graphene/gold nanoparticle hydrogel film through the hydrothermal method is reported. The hydrogel film could be formed on a glass substrate under hydrothermal conditions, and upon freeze-drying, the aerogel film of 40 μm thickness with satisfying flexibility and strength is obtained. The aerogel composite film is characterized by scanning/transmission electron microscopy, X-ray diffraction, Raman spectroscopy and X-ray photoelectron spectroscopy. Moreover, the aerogel film is directly used as the electrochemical electrode for sensing H

A variety of deactivated arenes were nitrated to their corresponding nitro derivatives in excellent yields under high-speed ball milling condition using Fe(NO3)3·9H2O/P2O5 as nitrating reagent. A radical involved mechanism was proposed for this facial, eco-friendly, safe, and effective nitration reaction.