From rich peanut oil to fragrant olive oil, various types of edible vegetable oils not only enrich people's food culture, but also meet diversified nutritional needs. With the improvement of the national economy and residents' living standards, the consumption of edible vegetable oils continues to grow, and it is particularly important to ensure its quality and safety. 1. Use EPR Technology to Scientifically Evaluate the Quality of Edible Oil Electron paramagnetic resonance (EPR) technology, with its unique advantages (no pretreatment required, in-situ non-destructive, direct sensitivity), plays an important role in edible oil quality monitoring. As a highly sensitive detection method, EPR can deeply explore the unpaired electron changes in the molecular structure of edible oils. These changes are often microscopic signs of the early stages of oil oxidation. The essence of oil oxidation is a free radical chain reaction. The free radicals in the oxidation process are mainly ROO·, RO· and R·. By identifying oxidation products such as free radicals, EPR technology can scientifically evaluate the degree of oxidation and stability of edible oils before they show obvious sensory changes. This is essential to promptly detect and prevent grease deterioration caused by improper storage conditions such as light, heat, oxygen exposure or metal catalysis. Considering that unsaturated fatty acids are easily oxidized, edible oils face the risk of rapid oxidation even under normal temperature conditions, which not only affects their flavor and nutritional value, but also shortens the shelf life of the product. Therefore, the use of EPR technology to scientifically evaluate the oxidation stability of oils can not only provide consumers with safer and fresher edible oil products, but also effectively guide the rational use of antioxidants, ensure the quality control of oil-containing foods, and extend the shelf life of market supply. . In summary, the application of electron paramagnetic resonance technology in the field of edible oil quality monitoring is not only a vivid manifestation of scientific and technological progress serving the people, but also an important line of defense for maintaining food safety and protecting public health. 2. Application cases of EPR in oil monitoring Principle: A variety of free radicals will be generated during lipid oxidation. The generated free radicals are more active and have shorter lifespans. Therefore, the spin capture method is often used for detection (the spin capture agent reacts with the active free radicals to form a more stable Free radical adducts, PBN is generally used as a spin trap). (1) Evaluate the oxidation stability of oil (the influence of external factors such as temperature on the oxidation stability of oil can be observed) The antioxidant capacity of a product can be determined by measuring the concentration of free r...
View MorePorous adsorbents play an important role in the fields of environmental purification, energy storage and catalytic conversion due to their unique porous structure and properties. Porous adsorbents usually have high specific surface area and rich pore distribution, which can effectively interact with molecules in gas or liquid. Using static gas adsorption method to accurately characterize parameters such as BET and Pore Distribution, can help to gain a deeper understanding of the properties and adsorption performance of porous adsorbents. BET and Pore Distribution of porous adsorbents Porous adsorbents are a type of material with high specific surface area and rich pore structure, which can capture and fix molecules in gas or liquid through physical or chemical adsorption. There are many types of them, including inorganic porous adsorbents (activated carbon, silica gel, etc.), organic Polymer adsorbents (ion exchange resins, etc.), coordination polymers (MOFs, etc.) and composite porous adsorbents, etc. A thorough understanding of the physical properties of porous adsorbents is critical to optimizing performance and expanding application areas. The application directions of BET Surface Area & Porosimetry Analyzer in the porous adsorbent industry mainly include quality control, research and development of new materials, optimization of separation processes, etc. By accurately testing the specific surface area and pore distribution, the performance of porous adsorbents can be improved in a targeted manner to meet specific application needs and improve the selective adsorption of target molecules. In summary, analyzing the specific surface area and pore distribution of porous adsorbents through gas adsorption characterization is beneficial to evaluate the adsorption capacity, selectivity and efficiency, and is of great significance in promoting the development of new high-efficiency adsorbents. Characterization of gas adsorption properties of MOFs materials Metal-organic framework materials (MOFs) have become a new type of adsorption material that has attracted much attention due to its high porosity, large specific surface area, adjustable structure and easy functionalization. Through the synergistic regulation of functional group modification and pore size adjustment, the CO2 capture and separation performance of MOFs materials can be improved to a certain extent. UiO-66 is a widely used MOFs adsorbent, often used in gas adsorption, catalytic reactions, molecular separation and other fields. The following is a case of characterization of UiO-66 material using the CIQTEK V-3220&3210 BET Surface Area & Porosimetry Analyzer. As shown on the left side of Figure 1, the specific surface area of UiO-66 is 1253.41 m2/g. A high specific surface area can provide more active sites, which is beneficial to improving its adsorption performance. It can be seen from t...
View MoreUse a Scanning Electron Microscope (SEM) to look at cat hair Hair is a derivative of the stratum corneum of the skin epidermis,which is also one of the characteristics of mammals. The hair of all animals has its basic shape and structure, with many differentiated hair morphologies (such as length, thickness, color, etc.). That must be closely related to its microstructure. Therefore, the microstructure of hair has also been the focus of research for many years . In 1837, Brewster used optical microscopy for the first time to discover the specific structure on the surface of hair, marking the beginning of the study of hair microstructure. In the 1980s, with the widespread application of electron microscope in the study of hair microstructure, the study of hair microstructure has been further improved and developed. Under the scanning electron microscope, the image of hair structure is clearer, more precise, and has a strong three-dimensional sense, high resolution and can be observed from different angles. Therefore, scanning electron microscope has become widely used in the observation of animal hair. Microstructure of cat hair under scanning electron microscope Cats are a widely raised pet. Most species have soft fur, which makes people quite fond of them.So, what information can we obtain from SEM images of cat hair? With questions in mind, we collected hair from different body parts of cats and used CIQTEK Tungsten Filament Scanning Electron Microscope to observe the microstructure of the hair.According to the characteristics of hair surface structure and morphology, it can be divided into four categories: finger-like, bud-like, wavy and squamous. The picture below shows the hair of a British shorthair cat. As can be seen from the scanning electron microscope image, its surface has an obvious wavy structure. The same surface structural units are the hair of dogs, roe deer, cows, and donkeys. Their diameters are generally between 20 and 60 μm. The width of the wavy unit is almost transverse to the entire circumference of the hair shaft, and the axial distance between each wavy unit is about 5 μm. The diameter of the British shorthair cat hair in the picture is about 58 μm. After zooming in, you can also see the surface hair scale structure. The width of the scales is about 5 μm, and the aspect ratio is about 12:1. The aspect ratio of the corrugated unit structure is small, and the aspect ratio is related to the flexibility of the hair. The larger the aspect ratio, the better the softness of the hair, and its stiffness is not easy to break. There is a certain gap between the hair scales and the hair shaft. A larger gap can store air, slow down the air flow speed, and reduce the heat exchange speed. Therefore, different surface unit shapes also determine the difference in thermal insulation performance. British shorthair cat hair surface /10kV/ETD British shorthair cat hair surface /10kV/ETD Likewise, cross-sections of h...
View MoreThe lizard skin cells used in this paper were provided by the research group of Che Jing, Kunming Institute of Zoology, Chinese Academy of Sciences. 1. Background Lizards are a group of reptiles that live on the earth with different body shapes and in different environments. Lizards are highly adaptable and can survive in a wide range of environments. Some of these lizards also have colorful colors as protection or for courtship behavior. The development of lizard skin coloration is a very complex biological evolutionary phenomenon. This ability is widely found in many lizards, but how exactly does it arise? In this article, we will take you to understand the mechanism of lizard discoloration in conjunction with CIQTEK Field Emission Scanning Electron Microscope products. 2. CIQTEK Field Emission Scanning Electron Microscope As a high-end scientific instrument, the scanning electron microscope has become a necessary characterization tool in the process of scientific research with its advantages of high resolution and wide range of magnification. In addition to obtaining information about the surface of the sample, the internal structure of the material can be obtained by applying transmission mode (Scanning transmission electron microscopy (STEM)) with the scanning transmission detector accessory on the SEM. In addition, compared with traditional transmission electron microscopy, the STEM mode on the SEM can significantly reduce the damage of the electron beam on the sample due to its lower accelerating voltage and greatly improve the image lining, which is especially suitable for structural analyses of soft material samples such as polymers and biological samples. CIQTEK SEMs can be equipped with this scanning mode, among which SEM5000, as a popular CIQTEK field emission model, adopts advanced barrel design, including high-voltage tunneling technology (SuperTunnel), low aberration non-leakage objective design, and has a variety of imaging modes: INLENS, ETD, BSED, STEM, etc., and the resolution of the STEM mode is up to 0.8nm@30kv. Animal body colors in nature can be divided into two categories according to the formation mechanism: pigmented colors and structural colors. Pigmented colors are produced through changes in the content of pigment components and the superposition of colors, similar to the principle of "three primary colors"; whereas structural colors are formed by reflecting light through fine physiological structures to produce colors with different wavelengths of reflected light, which is based on the principle of optics. The following figures (Figures 1-4) show the results of using the SEM5000-STEM accessory to characterize the iridescent cells in the skin cells of lizards, which have a structure similar to a diffraction grating, which we will tentatively call a crystal sheet, and which is capable of reflecting an...
View MoreScanning electron microscope as a commonly used microscopic analysis tools, can be observed on all types of metal fracture, fracture type determination, morphology analysis, failure analysis and other research. What is a metal fracture? When a metal is broken by an external force, two matching sections are left at the fracture site, which is called a "fracture". The shape and appearance of this fracture contains a lot of important information about the fracture process. By observing and studying the morphology of the fracture, we can analyze the cause, nature, mode, mechanism, etc., and also understand the details of the stress condition and crack expansion rate at the time of fracture. Like a "scene", the fracture retains the whole process of fracture occurrence. Therefore, for the study of metal fracture problems, observation and analysis of fracture is a very important step and means. Scanning electron microscope has the advantages of large depth of field and high resolution, and has been widely used in the field of fracture analysis. Application of Scanning Electron Microscope in Metal Fracture Analysis There are various forms of failure of metal fracture. Categorized by the degree of deformation before fracture, they can be divided into brittle fracture, ductile fracture, and mixed brittle and ductile fracture. Different fracture forms will have characteristic microscopic morphology, which can be characterized by SEM to help researchers to quickly perform fracture analysis. Ductile Fracture Ductile fracture is a fracture that occurs after a large amount of deformation of a member, which is mainly characterized by significant macroplastic deformation. The macroscopic morphology is a cup-and-cone fracture or a pure shear fracture, and the fracture surface is fibrous and consists of tough nests. As shown in Figure 1, microscopically its fracture is characterized by: the fracture surface consists of a number of tiny wineglass-shaped microporous pits, usually referred to as tough fossa. Toughness fossa is the trace left on the fracture surface after plastic deformation of the material in the range of micro-region generated by the micro-void, through the nucleation/growth/aggregation, and finally interconnected to lead to fracture. Fig. 1 Metal ductile fracture fracture/10kV/Inlens Brittle Fracture Brittle fracture is the fracture of a member without significant deformation. There is little plastic deformation of the material at the time of fracture. While macroscopically it is crystalline, microscopically it includes fracture along the crystal, disintegration fracture or quasi-disintegration fracture. As shown in Fig. 2, a mixed brittle-ductile fracture fracture of the metal, in the ductile fracture region, a distinctive toughness nest feature can be observed. In the brittle fracture region, it belongs to along-crystalline brittle fracture, which refers to the fract...
View More5A molecular sieve is a kind of calcium-type aluminosilicate with cubic lattice structure, also known as CaA-type zeolite. 5A molecular sieve has developed pore structure and excellent selective adsorption, which is widely used in the separation of n-isomerized alkanes, the separation of oxygen and nitrogen, as well as natural gas, ammonia decomposition gas, and the drying of other industrial gases and liquids. 5A molecular sieve has an effective pore size of 0.5 nm, and the determination of the pore distribution is generally characterized by gas adsorption using a physical adsorption instrument. The effective pore size of 5A molecular sieve is about 0.5 nm, and its pore size distribution is generally characterized by gas adsorption using physical adsorption instrument. The specific surface and pore size distribution of 5A molecular sieves were characterized by CIQTEK EASY-V series specific surface and pore size analyzers. Before testing, the samples were degassed by heating under vacuum at 300℃ for 6 hours. As shown in Fig. 1, the specific surface area of the sample was calculated as 776.53 m2/g by the multi-point BET equation, and then the microporous area of the sample was obtained as 672.04 m2/g, the external surface area as 104.49 m2/g, and the volume of the microporous as 0.254 cm3/g by t-plot method, which showed that the microporous area of this molecular sieve accounted for about 86.5%. In addition, the analysis of the N2 adsorption-desorption isotherm plot of this 5A molecular sieve (Fig. 2, left) reveals that the adsorption isotherm shows that the adsorption amount increases sharply with the increase of the relative pressure when the relative pressure is small, and the filling of micropores occurs, and the curve is relatively flat after reaching a certain value, which suggests that the sample is rich in micropores. The microporous pore size distribution calculation using the SF model (Fig. 2, right panel) yielded a concentrated microporous pore size distribution at 0.48 nm, which is consistent with the pore size of 5A molecular sieves. Fig. 1 Specific surface area test results (left) and t-Plot results (right) of 5A molecular sieve Fig. 2 N2-sorption and desorption isotherms (left) and SF-pore size distribution plots (right) of 5A molecular sieve samples CIQTEK Automatic BET Surface Area & Porosimetry Analyzer | EASY-V 3440 EASY-V 3440 is the BET specific surface area and pore size analysis instrument developed independently by CIQTEK, using the static volumetric method. ▪ Specific surface area testing, range 0.0005 (m2/g) and above. ▪ Pore size analysis: 0.35 nm-2 nm (micropore), micropore size distribution analysis; 2 nm-500 nm (mesopore or macropore). ▪ Four analysis stations, simultaneous testing of 4 samples. ▪ Equipped with the molecular pump.
View MoreZeolite imidazolium skeleton (ZIFs) materials as a subclass of metal-organic skeletons (MOFs), ZIFs materials combine the high stability of inorganic zeolites and the high specific surface area, high porosity and tunable pore size of MOFs materials, which can be applied to efficient catalytic and separation processes, so ZIFs and their derivatives have good potential for use in catalysis, adsorption and separation, electrochemistry, biosensor and biomedicine and other fields with good application prospects. The following is a case study of the characterization of ZIF molecular sieves using CIQTEK EASY-V series specific surface and pore size analyzer. As shown in Fig. 3 left, the specific surface area of this ZIF molecular sieve is 857.63 m2/g. The material has a large specific surface area which is favorable for the diffusion of reactive substances. From the N2-adsorption and desorption isotherms (Fig. 3, right), it can be seen that there is a sharp increase in adsorption in the low partial pressure region (P/P0 < 0.1), which is attributed to the filling of micropores, indicating that there is a certain amount of microporous structure in the material, and there is a hysteresis loop within the range of P/P0 of about 0.40 to 0.99, which suggests that there is an abundance of mesoporous structure in this ZIF molecular sieve. The SF-pore size distribution graph (Fig. 4, left) shows that the most available pore size of this sample is 0.56 nm. The total pore volume of this ZIF molecular sieve is 0.97 cm3/g, and the microporous volume is 0.64 cm3/g, with 66% of micropores, and the microporous structure can significantly increase the specific surface area of the sample, but the molecular sieve will limit the catalytic activity under certain conditions due to the smaller pore size. However, under certain conditions, the smaller pore size will limit the diffusion rate of the catalytic reaction, which makes the performance of molecular sieve catalyst limited, however, the mesoporous structure can obviously make up for this defect of the microporous structure, so the structure of the combination of microporous-mesoporous can effectively solve the problem of the limitation of the mass transfer capacity of the traditional molecular sieve with a single pore. Fig. 1 Specific surface area test results (left) and N2-sorption and desorption isotherms (right) for ZIF molecular sieves Fig. 2 SF-pore size distribution (left) and NLDFT-pore size distribution (right) of ZIF molecular sieve
View MoreThe characterization of copper foil morphology by scanning electron microscopy can help researchers and developers to optimize and improve the preparation process and performance of copper foils to further meet the existing and future quality requirements of high-performance lithium-ion batteries. Wide Range of Copper Applications Copper metal is widely used in lithium-ion batteries and printed circuit boards because of its ductility, high conductivity, ease of processing and low price. Depending on the production process, copper foil can be categorized into calendered copper foil and electrolytic copper foil. Calendered copper foil is made of copper blocks rolled repeatedly, with high purity, low roughness and high mechanical properties, but at a higher cost. Electrolytic copper foil, on the other hand, has the advantage of low cost and is the mainstream copper foil product in the market at present. The specific process of electrolytic copper foil is (1) dissolving copper: dissolve raw copper to form sulfuric acid-copper sulfate electrolyte, and remove impurities through multiple filtration to improve the purity of the electrolyte. (2) Raw foil preparation: usually polished pure titanium rolls as the cathode, through electrodeposition of copper ions in the electrolyte is reduced to the surface of the cathode to form a certain thickness of copper layer. (3) Surface treatment: the raw foil is peeled off from the cathode roll, and then after post-treatment, the finished electrolytic copper foil can be obtained. Figure 1 Electrolytic Copper Foil Production Process Copper Metal in Lithium-ion Batteries Lithium-ion batteries are mainly composed of active materials (cathode material, anode material), diaphragm, electrolyte and conductive collector. Positive potential is high, copper is easy to be oxidized at higher potentials, so copper foil is often used as the anode collector of lithium-ion batteries. The tensile strength, elongation and other properties of copper foil directly affect the performance of lithium-ion batteries. At present, lithium-ion batteries are mainly developed towards the trend of "light and thin", so the performance of electrolytic copper foil also puts forward higher requirements such as ultra-thin, high tensile strength and high elongation. How to effectively improve the electrolytic copper foil process to enhance the mechanical properties of copper foil is the main research direction of copper foil in the future. Suitable additive formulation in the foil making process is the most effective means to regulate the performance of electrolytic copper foil, and qualitative and quantitative research on the effect of additives on the surface morphology and physical properties of electrolytic copper foil has been a research hotspot for scholars at home and abroad. In materials science, the microstructure determines its mechanical properties, and the use of scanning electron microscopy to characterize the changes in the surface micro-m...
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