Latest ArticlesThe research on gas-liquid multiphase reactions using micro reactors is becoming increasingly widespread, given their excellent mass transfer performance. Establishing an accurate and reliable method to measure the gas-liquid mass transfer performance of micro reactors is crucial for evaluating and optimizing the design of micro reactor structure. In this paper, the physical absorption method of aqueous solution-CO2 and the chemical absorption method of sodium carbonate solution-CO2 were proposed. By analyzing the chemical reaction equilibrium during the absorption process, the relationship between the mass transfer of CO2 and the solubility of hydroxide ions in the solution was established, and the total gas-liquid mass transfer coefficient was immediately obtained by measuring the pH value. The corresponding testing platform and process have been established based on the characteristics of the proposed method to ensure fast and accurate measurement. In addition, the chemical absorption method takes into account temperature factors that were not previously considered. The volumetric mass transfer coefficient measured by these two methods is in the same range as those measured by other methods using the same microchannel structure in previous literature. The methods have the advantages of low equipment cost, faster measurement speed, and simpler procedures, which can facilitate its wide application to the evaluation of the mass transfer performance and hence can guide the structure optimization of microchannel reactors.
Polysubstituted chiral γ-butyrolactones are the core structural units of many natural products and high value-added flavors and fragrances used in the food and cosmetic industry. Current enzymatic cascade synthesis of these molecules faces the problems of low enzyme activity and phase separation in batch reaction, resulting in low productivity. Herein, we report a new continuous-flow process to synthesize the optically pure Nicotiana tabacum lactone (3S,4S)-4a and whisky lactone (3R,4S)-4b from α,β-unsaturated γ-ketoesters. A new ene reductase (ER) from Swingsia samuiensi (SsER) and a carbonyl reductase (SsCR) were engineered by directed evolution to improve their activity and thermostability. The continuous-flow preparative reactions were performed in two 3D microfluidic reactors, generating (3S,4S)-4a (99% ee and 87% de) and (3R,4S)-4b (99% ee and 98% de) with space-time yields 3 and 7.4 times higher than those of the batch reactions. The significant enhancement in the productivity of enzyme cascade catalysis brought by cutting-edge continuous microfluidic technology will benefit the general multi-enzyme catalytic systems in the future.
A practical method for the construction of difluoromethylene-containing 1,4-thiazine moieties using readily available diethyl bromodifluoromethanephosphonate (BrCF2PO(OEt)2) as difluorocarbene precusor has been developed. This transformation features the efficient capture of difluorocarbene by pyridinium 1,4-zwitterionic thiolates. A series of structurally novel and functionalized difluoromethylene-containing 1,4-thiazine derivatives were thus synthesized in good yields.
Realizing high-rate capability and high-efficiency utilization of polyanionic cathode materials is of great importance for practical sodium-ion batteries (SIBs) since they usually suffer from extremely low electronic conductivity and limited ionic diffusion kinetics. Herein, taking Na3.5V1.5Mn0.5(PO4)3 (NVMP) as an example, a reinforced concrete-like hierarchical and porous hybrid (NVMP@C@3DPG) built from 3D graphene ("rebar") frameworks and in situ generated carbon coated NVMP ("concrete") has been developed by a facile polymer assisted self-assembly and subsequent solid-state method. Such hybrids deliver superior rate capability (73.9 mAh/g up to 20 C) and excellent cycling stability in a wide temperature range with a high specific capacity of 88.4 mAh/g after 5000 cycles at 15 C at room temperature, and a high capacity retention of 97.1% after 500 cycles at 1 C (−20 ℃), and maintaining a high reversible capacity of 110.3 mAh/g in full cell. This work offers a facile and efficient strategy to develop advanced polyanionic cathodes with high-efficiency utilization and 3D electron/ion transport systems.
Single-emitter white organic light-emitting diode (WOLED) based on small organic molecule exhibits great potential in simplifying fabrication process of WOLEDs. However, the design and synthesis of molecule for highly efficient single-emitter WOLED still remains a challenge. Herein, two asymmetric donor-acceptor-acceptor' (D-A-A') type molecule (PTZ-PQ-F and PTZ-PQ-CF3) are developed by employing trifluoromethyl (CF3) or fluorine atom as secondary acceptor, which can exhibit white lighting with dual emission bands consisting of blue traditional fluorescence from quasi-axial (ax) conformer and orange thermally activated delayed fluorescence (TADF) from quasi-equatorial (eq) conformer. The introduction of CF3 into PTZ-PQ-CF3 greatly enhanced the photoluminescence quantum yield (PLQY) by suppressing the nonradiative deactivation. Owing to electron-inductive-effect of CF3, the "eq" conformer of PTZ-PQ-CF3 exhibits a much smaller ΔEST of 0.01 eV to realize more efficient reverse intersystem crossing (RISC) process, and then enhance the exciton utilization (nearly 100%) of the whole dual emission system. Consequently, single-emitter WOLEDs based on PTZ-PQ-CF3 show nearly standard white emission with EQE of 13.0% and CIE of (0.35, 0.36) in mCP host and show warm white emission with high EQE of 25.5% and CIE of (0.40, 0.47) in 35 DczPPy host, which are the best performance among reported single-emitter WOLEDs.
Cancer cell spheroids (CCS) are a valuable three-dimensional cell model in cancer studies because they could replicate numerous characteristics of solid tumors. Increasing researches have used matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) to investigate the spatial distribution of endogenous compounds (e.g., lipids) in CCS. However, only limited lipid species can be detected owing to a low ion yield by using MALDI. Besides, it is still challenging to fully characterize the structural diversity of lipids due to the existence of isomeric/isobaric species. Here, we carried out the initial application of MALDI coupled with laser-postionization (MALDI-2) and trapped ion mobility spectrometry (TIMS) imaging in HCT116 colon CCS to address these challenges. We demonstrated that MALDI-2 is capable of detecting more number and classes of lipids in HCT116 colon CCS with higher signal intensities than MALDI. TIMS could successfully separate numerous isobaric/isomeric species of lipids in CCS. Interestingly, we found that some isomeric/isobaric species have totally different spatial distributions in colon CCS. Further MS/MS imaging analysis was employed to determine the compositions of fatty acid chains for isomeric species by examining disparities in signal intensities and spatial distributions of product ions. This work stresses the robust ability of TIMS and MALDI-2 imaging in analyzing endogenous lipids in CCS, which could potentially become powerful tools for future cancer studies.
An efficient NH and C(sp3)-H functionalization of aryl ketones with benzylamines/amino acids was developed under mild conditions by virtue of anodic oxidation. A variety of functionalized 2,5-diaryloxazoles were obtained with good to excellent yields. Moreover, some important natural products can be prepared by this method. The reaction features a broad substrate scope, scalability, metal-free and chemical oxidant-free.
Changes in trace substances in human metabolites, which are related to disease processes and health status, can serve as chemical markers for disease diagnosis and symptom monitoring. Real-time online detection is an inevitable trend for the future of health monitoring, and the construction of chips for detection faces major challenges. The response of sensors often fails to meet the requirements for chip-based detection of trace substances due to the low efficiency of interfacial heterogeneous reactions, necessitating a rational design approach for micro- and nano-structures to improve sensor performance with respect to sensitivity and detection limits. This review focuses on the influence of micro- and nano-structures that used in chip on sensing. Firstly, this review categorizes sensors into chemiresistors, electrochemical sensors, fluorescence sensors, and surface enhanced Raman scattering (SERS) sensors based on their sensing principle, which have significant applications in disease diagnosis. Subsequently, commencing from the application requirements in the field of sensing, this review focuses on the different structures of nanoparticle (NP) assemblies, including wire, layered, core-shell, hollow, concave and deformable structures. These structures change in the size, shape, and morphology of conventional structures to achieve characteristics such as ordered alignment, high specific surface area, space limitation, vertical diffusion, and swaying behavior with fluid, thereby addressing issues such as poor signal transmission efficiency, inadequate adsorption and capture capacity, and slow mass transfer speed during sensing. Finally, the design direction of micro- and nano-structures, and possible obstacles and solutions to promote chip-based detection have been discussed. It is hope that this article will inspire the exploration of interface micro- and nano-structures modulated sensing methods.
Although considerable research efforts have been devoted to the design and development of non-noble electrocatalysts for oxygen evolution reaction (OER), substantial enhancement of OER performance with commercial-scale water electrolysis remains a big challenge. This could result from the difficulties in detecting the intrinsic properties and overlooking the assembly process for electrochemical OER process. Here, we employ a microjet collision method to investigate the intrinsic OER activities of individual NiZnFeOx entities with and without a moderate magnetic field. Our results demonstrate that single NiZnFeOx nanoparticles (NPs) show the excellent OER performance with a lowest onset potential (~1.35 V vs. RHE) and a greatest magnetic enhancement (~118%) among bulk materials, single agglomerations and NPs. Furthermore, we explore the utility of theoretical investigation by density functional theory (DFT) calculations for studying OER process on NiZnFeOx surfaces without and with spin alignment, indicating monodispersed NiZnFeOx NPs with totally spin alignment facilitates the OER process under the external magnetic field. It is found that the well-dispersion of NiZnFeOx NPs would increase the electrical conductivity and the surface spin state, resulting in promoting their OER activities. This work provides a test for uncovering the essential roles of NPs assembly to a significant promotion of their magnet-assisted OER.
Piezoelectric catalysis, a new catalytic method, is widely used in the field of environmental sanitation, including waste water treatment and dye degradation. However, in the face of the growing environmental pollution problem, the efficiency of piezoelectric catalysis is still hampered by the stress variation in the natural environment. Therefore, it is particularly important to improve the catalytic efficiency of piezoelectric materials. We divide piezoelectric materials into two categories: inorganic piezoelectric materials and organic piezoelectric materials. Then the mainstream inorganic piezoelectric materials are divided into four subcategories, namely: (1) MTiO3 (M = Ba, Sr), (2) bi-class catalytic materials, (3) MoX2 (X = S, Se), and (4) ZnO piezoelectric materials. The mainstream organic piezoelectric materials are divided into PVDF and g-C3N4 materials. At the same time, the above materials are summarized to explain the excellent performance of materials from the perspective of structure and piezoelectric principle. In addition, we summarized the modification methods that can be applied to piezoelectric materials: (1) Morphology methods, (2) composites with heterojunctions, and (3) surface modification. Finally, we summarized the prospects of piezoelectric materials in the field of environment and water treatment.
No. 86 Xueyuan South Road, Haidian District, Beijing
010-62199257
qkjq@cast.org.cn
Copyright © 2025 China Association for Science and Technology. All rights reserved. For all open access content, the relevant licensing terms apply.
Sponsored by the Office of the Leading Group for Cybersecurity and Informatization of CAST, and supported by Science and Technology Review Publishing House
