Paper-based all-solid-state flexible asymmetric micro-supercapacitors fabricated by a simple pencil drawing methodology

A simple and novel methodology was developed for manufacturing interdigitated asymmetric all-solid-state flexible micro-supercapacitors (MSCs) by a facile pencil drawing process followed by electrodepositing MnO₂ on one of the as-drawn graphite electrode as anode and the other as cathode.     

Investigation of Nonlinear Optical Modulation Characteristics of MXene VCrC for Pulsed Lasers

We report the surface morphology and the nonlinear absorption characteristics of MXene VCrC nanosheets prepared by the liquid-phase exfoliation method. The self-made MXene VCrC was applied as a saturable absorber in the Tm:YAP laser experiments, performing excellent Q-switching optical modulation characteristics in infrared range. With this absorber, a stable passively Q-switched 2 μm laser was achieved. Under an incident pump power of 3.52 W, a maximum output power of 280 mW was obtained with a T = 3% output coupler at a repetition frequency of 49 kHz. The corresponding pulse energy and peak power were 5.7 μJ and 6.6 W, respectively. The shortest pulse duration was 658 ns at the repetition rate of 63 kHz with a T = 1% output coupler.     

In-solution direct oxidative coupling for the integration of sulfur/selenium into DNA-encoded chemical libraries

Sulfur/selenium-containing electron-rich arenes (ERAs) exist in a wide range of both approved and investigational drugs with diverse pharmacological activities. These unique chemical structures and bioactive properties, if combined with the emerging DNA-encoded chemical library (DEL) technique, would facilitate drug and chemical probe discovery. However, it remains challenging, as there is no general DNA-compatible synthetic methodology available for the formation of C–S and C–Se bonds in aqueous solution. Herein, an in-solution direct oxidative coupling procedure that could efficiently integrate sulfur/selenium into the ERA under mild conditions is presented. This method features simple DNA-conjugated electron-rich arenes with a broad substrate scope and a transition-metal free process. Furthermore, this synthetic methodology, examined by a scale-up reaction test and late-stage precise modification in a mock peptide-like DEL synthesis, will enable its utility for the synthesis of sulfur/selenium-containing DNA-encoded libraries and the discovery of bioactive agents.

DNA-compatible direct oxidative coupling using various sulfur/selenium sources has been achieved, featuring pre-functionalization-free substrates and transition metal-free condition.     

Synthesis and Biological Activity of Novel Furan/Thiophene and Piperazine‐Containing (Bis)1,2,4‐triazole Mannich Bases

Series of novel furan/thiophene and piperazine‐containing 1,2,4‐triazole Mannich bases and bis(1,2,4‐triazole) Mannich bases have been conveniently synthesized via Mannich reaction with triazole Schiff bases, various piperazine derivatives, and formaldehyde as intermediates in good yields. Their structures were characterized by melting points, ¹H NMR, ¹³C NMR, IR and elemental analysis. The preliminary bioassay showed that most compounds exhibited significant in vitro and in vivo fungicidal activity against several test plant fungi. Among 32 new compounds, the trifluoromethyl‐containing compounds showed superior activity than the methyl‐containing ones. Several compounds, such as F8 , F9 , F10 , G5 , H7 , H8 , I3 and I4 , were comparable with some commercial fungicides against different fungi during the present study and could be further structurally optimized. Meanwhile, several compounds showed good herbicidal activity against Brassica campestris at 100 µg/mL and KARI inhibitory activity at 200 µg/mL. However, compounds exhibited poor insecticidal activity against oriental armyworm at 200 µg/mL in the preliminary studies. The research results will provide useful information for the design and discovery of new agrochemicals with novel heterocyclic structures.     

Co-Intercalation of Dual Charge Carriers in Metal-Ion-Confining Layered Vanadium Oxide Nanobelts for Aqueous Zinc-Ion Batteries

Vanadium-based oxides with high theoretical specific capacities and open crystal structures are promising cathodes for aqueous zinc-ion batteries (AZIBs). In this work, the confined synthesis can insert metal ions into the interlayer spacing of layered vanadium oxide nanobelts without changing the original morphology. Furthermore, we obtain a series of nanomaterials based on metal-confined nanobelts, and describe the effect of interlayer spacing on the electrochemical performance. The electrochemical properties of the obtained Al_2.65V₆O₁₃ ⋅ 2.07H₂O as cathodes for AZIBs are remarkably improved with a high initial capacity of 571.7 mAh ⋅ g⁻¹ at 1.0 A g⁻¹. Even at a high current density of 5.0 A g⁻¹, the initial capacity can still reach 205.7 mAh g⁻¹, with a high capacity retention of 89.2 % after 2000 cycles. This study demonstrates that nanobelts confined with metal ions can significantly improve energy storage applications, revealing new avenues for enhancing the electrochemical performance of AZIBs.     

Lewis Acid‐Catalyzed Intramolecular [3 + 2] Cross‐Cycloaddition of Donor‐ Acceptor Epoxides with Alkenes for Construction of Oxa‐[n.2.1] Skeletons

The first LA‐catalyzed [3 + 2]IMCC of GDA‐epoxides with carbon‐carbon double bonds has been developed. This provides an efficient and general strategy for construction of bridged oxa‐[n.2.1] skeletons. A novel S_N‐like mechanism through a carbon‐carbon bond cleavage of epoxide ring has been proposed.     

Surface Iron Species in Palladium–Iron Intermetallic Nanocrystals that Promote and Stabilize CO2 Methanation

It is of pivotal importance to develop efficient catalysts and investigate the intrinsic mechanism for CO₂ methanation. Now, it is reported that PdFe intermetallic nanocrystals afforded high activity and stability for CO₂ methanation. The mass activity of fct-PdFe nanocrystals reached 5.3 mmol g⁻¹ h⁻¹, under 1 bar (CO₂:H₂=1:4) at 180 °C, being 6.6, 1.6, 3.3, and 5.3 times as high as that of fcc-PdFe nanocrystals, Ru/C, Ni/C, and Pd/C, respectively. After 20 rounds of successive reaction, 98 % of the original activity was retained for PdFe intermetallic nanocrystals. Further mechanistic studies revealed that PdFe intermetallic nanocrystals enabled the maintenance of metallic Fe species via a reversible oxidation–reduction process in CO₂ methanation. The metallic Fe in PdFe intermetallic nanocrystals induced the direct conversion of CO₂ into CO* as the intermediate, contributing to the enhanced activity.     

LC4—M材料复合型韧断主要影响因素的分析

通过分析LC4－M铝合金材料在不同复合比载荷下的断裂试验结果,参照常规断裂现象,修正了一般断裂试验中认定裂纹启裂方向的方法,结合不同复合比下裂尖附近应力三维、主应力方向的计算分析,得到：在裂端的钝化变形区域、应力三维度的极大值处,对应于裂纹的启裂位置,即使在高韧性材料中发生剪切断裂的情况下也是如此;裂纹的启裂方向在拉伸断裂时与启裂点最大拉应力方向有关,在剪切断裂时启裂点最大剪应力方向有关,引起两种形式断裂的主要因数和破坏机理有很大不同。     

Supersaturated Design with More Than Two Levels

gO. IntroductionA fractional factorial design is called supersaturated if the number of factors includedexceeds the limitation for keeping all the factors estimable, ignoring interactions. Sincesupersaturated designS can accommodate large nUInbers of factors, they are thought usefulin screening experhoellts.The research work on tWO-level supersaturated design was st8lted in the late fifties andearly staies (see [1,101). The subject has been gaining more and more renewed interest inthe last …