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The determination of molar mass by the freezing-point depression method is one of the classical experiments in physical chemistry. Given the existing materials and literature of physical chemistry on some content in regard to freezing point determination is not detailed enough, such as the cause of the undercooling phenomenon is short of a comprehensive, in-depth explanation; the determination of the approximate freezing point of pure solvent needs to observe ‘when there is solid precipitation’, where does the precipitation of solid appear firstly in the glass tube? What is the morphology of the precipitated solid? The existence of these problems will cause students trouble when operating experiments. Aiming at the above problems, the whole process of solvent solidification was filmed through experimental innovation in this paper, the specific position and morphology of solid precipitation were analyzed, and it can be concluded that it was appropriate for students to observe the solid to precipitate flocculent preferentially from the glass tube bottom during experimental operation. Through the freezing-point depression method, the details of solvent solid precipitation were observed, the molecular weight of the solute was calculated and analyzed, and reliable experimental results were obtained. In this paper, the operation details of the freezing-point depression method are deeply studied and discussed, which can effectively avoid or eliminate the problems in the experimental operation and greatly improve the experimental effect on students. [ABSTRACT FROM AUTHOR]

The properties and service life of composite materials used for space structure are affected by atomic oxygen irradiation, ultraviolet radiation and other space rays in the space environment. It′s important to prepare a composite material with space radiation resistance for the operation safety of space structure. Here, the ultra-thin prepreg with fiber mass per unit area of (35±2) g/m² was prepared by using the space radiation resistant epoxy resin as the matrix and carbon fiber (T300) as the reinforcement. The space radiation resistant composite laminates were prepared by ultra-thin prepreg, and the atomic oxygen resistance, ultraviolet radiation resistance and vacuum escape properties of the composite laminates were characterized. The results indicate that the tensile strength of 0 (°) and 90 (°) decreased by11% and 5. 5%, respectively, and mass loss less than 0. 35% after exposure under atomic oxygen (5×1020 atoms/cm²). After UV exposure (3000 ESH), the tensile strength of 0 (°) loss 1. 6%. However, the tensile strength of 90 (°) increased from 65. 9 to 75. 3 MPa. In addition, the Total Mass Loss (TML) and Collected Volatile Condensable Materials (CVCM) of the composite from outgassing in a vacuum environment for 24 h are less than 1% and 0. 1%, respectively(the material is placed at 125 ℃, less than 7×10−3 Pa). The carbon fiber reinforced composites prepared in this paper have excellent resistance to space radiation and can be used as candidate composite materials for largescale space structures. [ABSTRACT FROM AUTHOR]

In recent years, with the rapid development of the global lithium battery industry, the demand for lithium as a raw material is also increasing. There are abundant lithium resources in salt lake brine, however, the concentration of lithium is very low and the composition is complex. The development of highly efficient separation technology to extract lithium resources from brine has important economic value and strategic significance. The solvent extraction method has the advantages of large processing capacity, high extraction efficiency, excellent selectivity and easy operation on a large scale, resulting in promising industial application. This paper summarized the separation of lithium resources from salt lakes using various solvent extraction reagents in the last five years, including β-diketones, organophosphorus extractants, macrocyclic receptors, 4-phosphorylpyrazolone, ionic liquids and deep eutectic solvents. The mechanism, application scenarios, advantages and disadvantages of these extractants were systematically summarized. In view of the problems of the extraction system, the intensification technology of the extraction process was further introduced, such as membrane extraction intensification and electric field intensification. Finally, we gave the suggestions for the studies improvement of the extractants and prospected the development of extractants in the future. [ABSTRACT FROM AUTHOR]

Sophorolipids (SLs) are a kind of biosurfactants with the highest potential for industrial application, and the degree of acetylation in their sugar chains has an important influence on their surface interface activity, and physicochemical properties. By homologous recombination, the research group constructed the acetyltransferase gene-deficient strain, and nonacetylated SLs was prepared by fermentation with oleic acid and glucose as biphasic carbon sources. In this paper, the structure of nonacetylated SLs was analyzed by high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS), and the physicochemical properties of acetylated SLs produced by wild strains were compared. The results showed that the hydrophobic groups of nonacetylated SLs produced by nonacetylated strains were mainly octadecenoic acid, and the hydrophilic groups were mainly nonacetylated sophoricoside, in which the contents of lipoid, acidic and bolatype SLs were 26. 99%，49. 98% and 23. 03% respectively. The sophorolipids produced by wild strains are mainly acetylated sophorolipids, and the mass fractions of lactone and acid types are 97. 86% and 2. 14% respectively. Its hydrophobic group is mainly octadecenoic acid. The solubility of nonacetylated SLs in water is as high as 485. 8 g/L, which is 14 times higher than acetylated SLs, and it has better foaming performance and foam stability. At the same time, the emulsifying performance of nonacetylated SLs is 26. 7 times higher than acetylated SLs. Due to the increase of hydrophilicity of the missing acetyl group, the surface activity of deacetylation SLs decreased, and the surface tension of aqueous solution was reduced to 41. 0 mN/m, which was higher than that of acetylated sophorolipid (36. 2 mN/m). The hydrophilic and lipophilic balance value is 13, which is higher than that of acetylation SLs (11). Two kinds of sophorolipid have good hard water resistance, but weak acid and alkali resistance. [ABSTRACT FROM AUTHOR]

Cellulose is the most abundant natural polymer resource on the earth. It has the advantages of renewable, low cost, and good biocompatibility. At the same time, cellulose has many dipoles and strong electron donating ability due to its high crystallinity and rich polar hydroxyl group. It has the good piezoelectric effect and can be used as raw material of green electronic products. In this paper, manganese dioxide nanorods (MnO2) with high purity, small particle size and good dispersion were prepared by a hydrothermal method, which doped into type I cellulose to prepare a MnO2/cellulose composite film. The effects of different contents of MnO2 on the current output performance of the MnO2/cellulose composite film piezoelectric nanogenerator were investigated. With the increase of manganese dioxide content, the output current shows a trend of first increasing and then decreasing. When the doping quality of MnO2 is 30%, the maximum thermal weight loss rate of the composite film is 325 ℃, which is 44 ℃ higher than that of pure cellulose. The O1s binding energy values of the composite film were different from pure cellulose and manganese dioxide, which proves the existence of chemical bonding between cellulose and manganese dioxide. The piezoelectric nanogenerator with microampere-level current was fabricated by using the MnO2/cellulose composite film. The maximum output current is 80. 75 μA, and the output voltage is 1. 10 V. With the press of finger, the piezoelectric nanogenerator can drive a variety of electronic products such as light-emitting diode (LED) lights, calculators and electronic watches. This new type of green piezoelectric nanogenerator is based on cellulose, and MnO2 doping also improves the energy collection efficiency, which provides a new idea for promoting the development of nanogenerator technology. [ABSTRACT FROM AUTHOR]

In this paper, a new type of Al-Ga-In-Sn-Si alloy anode with high negative potential and high activation was successfully prepared by modifying low melting point alloy elements such as Ga, In and Sn. The corrosion behavior and electrochemical performance of Al-Ga-In-Sn-Si alloy were studied through material characterization and electrochemical tests. A seawater dissolved oxygen battery was constructed with carbon fiber brush-graphene-platinum (Pt-G@CFB) catalytic cathode. The long period discharge performance of the battery under different constant resistance in indoor static and real dynamic seawater environment was investigated. The electrochemical test results of aluminum anode show that the self-corrosion potential of Al-Ga-In-Sn-Si alloy is −1. 613 V(vs. Ag/AgCl), and the self-corrosion current density is 1. 431 mA/cm² . The battery discharge test results show that the battery voltage rises with the increase of load resistance. The average discharge voltages of the dissolved oxygen battery in seawater are the highest, which are 1. 73 and 1. 78 V respectively, under the load of 2000 Ω in indoor static and real dynamic seawater, and the average energy densities are the highest under the load of 1000 Ω. They are 549. 85 and 653. 44 Wh/kg, respectively. [ABSTRACT FROM AUTHOR]

In this paper, the complex Eu (HFA)4TPP (HFA=Hexafluoroacetylacetone, TPP= tetraphenylphosphonium) with high photoluminescence quantum yield and improved stability is prepared. The steric effect on luminescence performance is revealed by studying the crystal structures and luminescence properties of Eu(HFA)4Na and Eu(HFA)4TPP complexes. On this basis, the luminescent films are obtained by incorporating Eu(HFA)4TPP complex with high loading content into polymethyl methacrylate (PMMA) matrix, which shows a visible-light excitation window (240~450 nm) and high photoluminescence quantum yield of 60. 54%. In addition, the luminescent solar concentrators (LSC) in Eu(HFA)4TPP/PMMA film conformation is prepared. The optical conversion efficiency contribution of Eu(HFA)4TPP/PMMA film to the LSC is 0. 95% in the case of the G=1. 87, holding promise in photovoltaic fields. [ABSTRACT FROM AUTHOR]

The search for alternatives to fossil fuels has received a great deal of attention based on the urgency of reducing CO2 levels in the atmosphere and the demand for energy at this stage. Solar energy is the world's most abundant renewable energy source, and photocatalysis is a sunlight-driven chemical reaction process carried out on the surface of the photocatalyst. The realization of the carbon cycle is an urgent need for the development of human society. Photocatalysis has the advantages of low energy consumption and mild reaction conditions, and realizing the resource utilization of CO2 by simulating natural photosynthesis, which is one of the most promising means to solve this problem, and is of great significance for realizing carbon neutrality. The central issue in the case is the development of efficient, environmentally friendly and inexpensive catalysts. Titanium dioxide (TiO2 ) is favored in photocatalysis because of its high catalytic activity and excellent chemical stability. However, some bottlenecks still restrict the photocatalytic activity. Various methods have been tried to optimize the photocatalytic performance. This article summarizes the photocatalytic CO2 reduction based on TiO2 photocatalysts in recent years, which helps to comprehensively understand and grasp the research progress and trends in this field. This paper mainly discusses the mechanism of photocatalytic CO2 reduction, reaction system, and the research progress of TiO2-based catalysts in photocatalytic CO2 reduction. The active sites of TiO2-based photocatalysts are elaborated, focusing on the applications of titanium-oxo clusters, the construction of Lewis acid-base pairs, the establishment of heterojunctions, and the modulation of surface wettability. These strategies can not only increase the effective active sites on the catalyst surface, but also effectively enhance the separation efficiency of electron-hole pairs, so as to improve the photocatalytic CO2 reduction performance. Finally, the future opportunities and challenges in this field are prospected. [ABSTRACT FROM AUTHOR]

The safety issue of animal food has received widespread public attention due to increased reports of problematic foods. Once veterinary drugs are overused or abused in the process of animal husbandry, drug residues will bring serious harm to human health. Common residue detection methods have the disadvantages of high cost, slow speed and low efficiency, which usually requires professional personnel to operate, and the traditional physical and chemical methods can't meet the needs of food quality testing. As a result, the research and development of rapid and efficient detection methods for veterinary drug residues is necessary. In recent years, surface-enhanced Raman spectroscopy (SERS) has been widely used in many fields such as authenticity identification, illegal additives detection, agricultural and veterinary residues, etc, and has a broader development prospect in the field of food testing due to its advantages of fast detection and nondestructive. SERS is different from other detection methods in that it can rapidly identify target analytes through signal amplification and highly sensitive fingerprint spectroscopy for qualitative or semi-quantitative analysis. This paper mainly introduces the research and application of Raman spectroscopy and SERS in the detection of veterinary drug residues in foods of animal origin, focusing on the advantages of SERS, the pre-treatment of food samples, and the related research on the detection of a variety of veterinary drugs by SERS combined with other techniques, and proposing the challenges faced by SERS in practical monitoring. [ABSTRACT FROM AUTHOR]

The high performance liquid chromatographic (HPLC) fingerprints of TongFu XieXia Granules (TFXXG) are established, and the contents of Emodin, Chrysophanic acid, Rhein, Aloeemodin, Physcion, Magnolol and Honokiol are simultaneously determined. The separation is performed on a Waters Symmetry C18 column (2. 1 mm × 150 mm, 3. 5 µm) with a gradient elution of 0. 1% aqueous phosphoric acid (A) and methanol (B) as the mobile phases, at a flow rate of 0. 4 mL/min, with the column temperature at 30 ℃, the detection wavelength at 254 nm, and the injection volume of 10 µL. The fingerprints of 10 batches of TFXXG are established, and the similarity is calculated by using the “Evaluation system for similarity of chromatographic fingerprints of traditional Chinese medicines”(2012 version); the contents of Emodin, Chrysophanic acid, Rhein, Aloeemodin, Physcion, Magnolol and Honokiol are determined. The results show that a total of 25 common peaks is identified in the 10 batches of TFXXG, and the similarities are all above 0. 950; a total of 12 common peaks are identified, which are Sinapine thiocyanate, Caffeic acid, Echinacoside, Naringin, Neohesperidin, Aloeemodin, Rhein, Magnolol, Honokiol, Emodin, Chrysophanic acid and Physcion, respectively. The contents of Aloeemodin, Rhein, Magnolol, Honokiol, Emodin, Chrysophanic acid and Physcion are 0. 1244~0. 1304, 0. 4271~0. 4387, 3. 0479~3. 0853, 1. 2910~1. 3039, 0. 2427~0. 2523, 0. 7718~0. 7897 and 0. 5085~0. 5249 mg/g, respectively. The fingerprints and quantitative analytical methods constructed in this paper are reproducible and operable, and can be used to control the quality of TFXXG. [ABSTRACT FROM AUTHOR]

Organophosphorus pesticides (OPs), as one of the most toxic pesticides, have the characteristics of wide use, large usage and great harm to human health. With people's longing and continuous pursuit of a healthy life, it is particularly urgent and important to build accurate, sensitive, convenient and fast OPs residual analysis and detection sensor. Because of the unique optical, electrochemical and biological properties of nanomaterials, OPs detection sensors based on nanomaterials have the advantages of sensitivity, high efficiency and economy. In this paper, the domestic and foreign sensors for detecting OPs residues based on rare earth doped up conversion nanomaterials, metal nanomaterials, metal oxide nanomaterials, carbon nanomaterials and quantum dot nanomaterials from 2015 to 2023 are reviewed, providing ideas and basis for the subsequent development of nanomaterial-based OPs multi residue detection sensors. [ABSTRACT FROM AUTHOR]

It is of great significance to select appropriate supports to support Pt nanoparticles for the preparation of efficient phenol hydrogenation catalysts. In this paper, Pt nanoparticles confined into the inner wall of titanium oxide nanotubes were prepared by template assisted method of atomic layer deposition technology. The specific preparation method was to use carbon nanofibers as templates, successively depositing Pt nanoparticles and thick titanium oxide shell on the templates surface. Then, the templates were removed by high-temperature sintering, through which Pt nanoparticles confined into the inner wall of titanium oxide nanotubes can be obtained. The particle size of the Pt nanoparticles ranged from 2. 0 to 3. 2 nm at a sintering temperature of 500 ℃, with an average size of 2. 6 nm. Transmission electron microscopy results confirmed that Pt nanoparticles with highly uniform size were evenly dispersed and embedded into the inner wall of the hollow channel of titanium oxide nanotubes. The results of the catalytic performance of phenol hydrogenation show that the small-size Pt nanoparticles have the best phenol hydrogenation activity, with a Turnover Frequency (TOF) value of 482. 1 h−1 at a sintering temperature of 500 ℃ . In addition, compared with the conventional Pt nanoparticles with the same size supported on the outer wall of titanium oxide nanotubes, it is found that the confined catalyst shows better catalytic activity. Furthermore, due to the protective effect of titanium oxide nanotubes, it can effectively prevent the aggregation and falling off of Pt nanoparticles in the reaction process. After the reaction, the Pt content only decreased by 4. 52%, and there were no significant changes in the morphology observed, thus the confined catalyst showing excellent catalytic stability compared with the supported catalyst. [ABSTRACT FROM AUTHOR]

Amino acids, as the fundamental components of proteins, contain both acidic and basic groups (amino and carboxyl groups) in their molecular structure, and amino acid ionic liquids with amino acids as anions or cations can be conveniently formulated. Amino acid ionic liquids with the advantages of high solubility, low melting point, and high thermal stability. These liquids find applications as carbon precursors, solvents, catalysts, and adsorbents in various fields such as energy storage, biomass utilization, and carbon capture. This paper provides an overview of the research progress made in the utilization of amino acid ionic liquids in supercapacitor electrode materials, biomass conversion, and carbon dioxide separation and capture in the past seven years. Specifically, it focuses on the advancements in utilizing amino acid ionic liquids as precursors in supercapacitor carbon electrode materials. Furthermore, it highlights the potential applications and future development prospects of amino acid ionic liquids. [ABSTRACT FROM AUTHOR]

Near-infrared phosphor-converted light-emitting diodes (NIR pc-LEDs) are expected to be the next-generation NIR light sources, with the advantages of small size, broad bandwidth, and easy tuning of emission peaks. The key for NIR pc-LEDs is to develop highly efficient broadband NIR phosphors that can be effectively excited by blue light. Cr3+ -activated NIR phosphors have been widely studied, and this paper reviews the development of Cr3+ -doped NIR phosphors peaked at 800~900 nm. Based on phosphates, pyroxenes, and other systems, the relationships between the structure and the emission peak and bandwidth are summarized. Furthermore, to enhance the NIR performance, strategies of synthesis technology optimization, components design, and co-doping sensitizers are discussed in detail. [ABSTRACT FROM AUTHOR]

Single-atom catalysts (SACs) have attracted much attention due to their unique structure and properties, especially in terms of maximizing the utilization of atoms and improving the intrinsic catalytic activity. In recent years, SAC-based advanced oxidation processes (AOPs) have become a new field in the environmental field, and have been widely used in the removal of various refractory organic pollutants. In this paper, the synthesis and characterization methods of SACs are analyzed, and the catalytic performance of SACs in different Fenton-like catalytic reactions is emphasized. In addition, tests of the continuous flow of SACs fixed on membrane or columnar filters are presented to explore the potential of SACs for practical applications in Fenton-like reactions. Finally, we prospect the future rational SACs design and the exploration direction of the Fenton-like reaction mechanism, aiming to improve the application potential of Fenton-like reaction in practical wastewater. [ABSTRACT FROM AUTHOR]

In recent years, due to the development of nuclear power and other industries, the pollution of heavy metals and radionuclides in water cannot be ignored, and the demand for clean water has become an important issue of global concern. Molybdenum disulfide (MoS2 ) nanomaterials have attracted much attention in the fields of sterilization, hydrogen storage, water purification,etc. Membrane technology has become one of the options for the removal of heavy metals and radionuclides from water based on the advantages of simple operation and high efficiency. In this paper, the research progress of MoS2-based nanomaterials and membranes in removing heavy metals and radionuclides from water is summarized, focusing on MoS2 synthesis and modification methods, the main affect factors and mechanisms of heavy metals and radionuclides removal by MoS2, the preparation of MoS2-modified membranes, and the research progress on removing heavy metals and radionuclides from water by membrane technology, which aims at efficiently removing heavy metals and radionuclides. [ABSTRACT FROM AUTHOR]

MicroRNA (miRNA) is the marker for early diagnosis of cancer and plays a key role in physiological and pathological processes, therefore real-time and accurate monitoring of miRNA is of great significance. Currently, signal amplification/magnification strategies for miRNA assay are mostly dependent on the involvement of coenzymes. In this paper, a highly sensitive and specific miRNA detection method based on gold nanoparticle (AuNPs) aggregation and hybridization chain reaction (HCR) enzyme-free amplification is established. An assisted hairpin probe (HP) and two universal hairpin probes (H1/H2) are designed. Both of them are single-stranded DNA (ssDNA) with sticky ends, which could stabilize AuNPs in aqueous solution and effectively prevent salt-induced aggregation. The target miRNA hybridizes with the HP loop region, initiating HCR to trigger the formation of double-stranded DNA (dsDNA) polymers. The dsDNA polymer has no sticky ends and no ability to stabilize gold nanoparticles, resulting in salt-induced aggregation of AuNPs, and the change of gold-colloidal solution from wine red to blue. Thus, miRNA can be detected by spectrophotometry. This strategy does not rely on enzymatic reactions, separation processes, and chemical modifications, and operation is simple. By designing the HP loop sequence, the detection of different targets can be realized and show good versatility. [ABSTRACT FROM AUTHOR]

Biomarkers, such as ions, small molecules, proteins, polysaccharides, nucleic acids, and cells, are involved in the building of organisms and play an important role in the life process. Accurate detection of these biomarkers is of great significance for disease research, early diagnosis, drug evaluation, and human health monitoring. The solid-state nanochannel is modified by functionalizing the outer surface of the nanochannel, which eliminates the restriction on the target molecule and greatly improves the speed and sensitivity of detection by means of a change based on the ion signal. This paper reviews the detection principle of solid-state nanochannels with modified outer surface in biomarkers, summarizes the research progress of solid-state nanochannels modified on outer surfaces in biomarker analysis, and briefly looks forward to the challenges and development opportunities of solid-state nanochannels modified on outer surfaces. [ABSTRACT FROM AUTHOR]