Applications

Drug powder is the main body of most drug formulations, and its efficacy depends not only on the type of drug, but also to a large extent on the properties of the powder that makes up the agent, including particle size, shape, surface properties and other kinds of parameters. The specific surface area and pore size structure of drug powders are related to the properties of powder particles such as particle size, hygroscopicity, solubility, dissolution and compaction, which play an important role in the purification, processing, mixing, production and packaging capabilities of pharmaceuticals.   In addition, the validity, dissolution rate, bioavailability and efficacy of drugs also depend on the specific surface area of the material. Generally speaking, the larger the specific surface area of pharmaceutical powders within a certain range, the faster the dissolution and dissolution rate will be correspondingly accelerated, which ensures the uniform distribution of drug content; however, too large a specific surface area will lead to the adsorption of more water, which is not conducive to the preservation and stability of drug efficacy. Therefore, accurate, rapid and effective testing of the specific surface area of pharmaceutical powders has always been an indispensable and critical part of pharmaceutical research.   Case Study of CIQTEK Application in Pharmaceutical Powder   We combines the actual characterization cases of different drug powder materials to clearly show the methods and applicability of this technology to characterize the physical properties of different drug surfaces, and then make some basic analysis on the expiration date, dissolution rate and efficacy of drugs, and help the pharmaceutical industry to develop with high quality.    The V-Sorb X800 series specific surface and pore size analyzer is a high throughput, fast and economical instrument, which can realize rapid testing of specific surface area of incoming and outgoing finished products, pore size distribution analysis, quality control, adjustment of process parameters, and prediction of drug performance, etc.   Automatic BET Surface Area & Porosimetry Analyzer CIQTEK EASY-V Series     CIQTEK SEMs   1、Scanning electron microscope and specific surface and pore size analyzer in montmorillonite dispersion   Montmorillonite is obtained from the purification and processing of bentonite, which has unique advantages in pharmacology because of its special crystal structure with good adsorption capacity, cation exchange capacity and water absorption and swelling capacity. For example: as API, drug synthesis, pharmaceutical excipients, etc.   Montmorillonite has a laminar structure and a large specific surface area, which can have a strong adsorption effect on toxic substances; it is electrostatically combined with digestive tract mucus proteins and plays a protective and repairing role on the digestive tract mucosa.  ...

Metallic materials are materials with properties such as luster, ductility, easy conductivity, and heat transfer. It is generally divided into two types: ferrous metals and non-ferrous metals. Ferrous metals include iron, chromium, manganese, etc. So far, iron and steel still dominate in the composition of industrial raw materials. Many steel companies and research institutes use the unique advantages of SEM to solve problems encountered in production and to assist in research and development of new products. Scanning electron microscopy with corresponding accessories has become a favorable tool for the steel and metallurgical industry to conduct research and identify problems in the production process. With the increase of SEM resolution and automation, the application of SEM in material analysis and characterization is becoming more and more widespread.   Failure analysis is a new discipline that has been popularized by military enterprises to research scholars and enterprises in recent years. Failure of metal parts can lead to degradation of workpiece performance in minor cases and life safety accidents in major cases. Locating the causes of failure through failure analysis and proposing effective improvement measures are essential steps to ensure safe operation of the project. Therefore, making full use of the advantages of scanning electron microscopy will make a great contribution to the progress of the metal material industry.     01 Electron microscope observation of tensile fracture of metal parts        Fracture always occurs in the weakest part of the metal tissue and records much valuable information about the whole process of fracture, so the observation and study of fracture has always been emphasized in the study of fracture. The morphological analysis of the fracture is used to study some basic problems that lead to the fracture of the material, such as the cause of fracture, the nature of fracture, and the mode of fracture. If we want to study the fracture mechanism of the material in depth, we usually have to analyze the composition of the micro-area on the surface of the fracture, and fracture analysis has now become an important tool for failure analysis of metal components.     Fig. 1 CIQTEK Scanning Electron Microscope SEM3100 tensile fracture morphology   According to the nature of fracture, the fracture can be broadly classified into brittle fracture and plastic fracture. The fracture surface of brittle fracture is usually perpendicular to the tensile stress, and the brittle fracture consists of glossy crystalline bright surface from the macroscopic view; the plastic fracture is usually fibrous with fine dimples on the fracture from the macroscopic view.   The experimental basis of fracture analysis is the direct observation and analysis of the macroscopic morphological and microstructural characteristics of the fracture surface. In many cases, the nature of the f...

Can you imagine a laptop hard drive the size of a grain of rice? Skyrmion, a mysterious quasiparticle structure in the magnetic field, could make this seemingly unthinkable idea a reality, with more storage space and faster data transfer rates for this "grain of rice. So how to observe this strange particle structure? The CIQTEK Scanning NV Microscope (SNVM), based on the nitrogen-vacancy (NV) center in diamond and AFM scanning imaging, can tell you the answer.     What is Skyrmion   At the same time, with such a high density of integrated electronic components on the chip, the thermal dissipation problem has become a huge challenge. People urgently need a new technology to break through the bottleneck and promote the sustainable development of integrated circuits.   Spintronics devices can achieve higher efficiency in information storage, transfer, and processing by exploiting the spin properties of electrons, which is an important way to break through the above dilemma. In recent years, topological properties in magnetic structures and their related applications are expected to be the information carriers of next-generation spintronic devices, which is one of the current research hotspots in this field.   The skyrmion (hereafter referred to as a magnetic skyrmion) is a topologically protected spin structure with quasiparticle properties, and as a special kind of magnetic domain wall, its structure is a magnetization distribution with vortices. Similar to the magnetic domain wall, there is also a magnetic moment flip in the skyrmion, but unlike the domain wall, the skyrmion is a vortex structure, and its magnetic moment flip is from the center outward, and the common ones are Bloch-type skyrmions and Neel-type skyrmions.   Figure 1: Schematic diagram of the structure of skyrmion. (a) Neel-type skyrmions (b) Bloch-type skyrmions   The skyrmion is a natural information carrier with superior properties such as easy manipulation, easy stability, small size, and fast driving speed. Therefore, the electronic devices based on skyrmions are expected to meet the performance requirements for future devices in terms of non-volatile, high capacity, high speed, and low power consumption.   What are the Applications of Skyrmions   Skyrmion Racetrack Memory Racetrack memory uses magnetic nanowires as tracks and magnetic domain walls as carriers, with electric current driving the motion of the magnetic domain walls. In 2013, the researchers proposed the skyrmion racetrack memory, which is a more promising alternative. Compared to the drive current density of a magnetic domain wall, the skyrmion is 5-6 orders of magnitude smaller, which can lead to lower energy consumption and heat generation. By compressing the skyrmions, the distance between adjacent skyrmions and the skyrmion diameter can be in the same order of magnitude, which can lead to higher storage density.   Figure 2: Skyrmion-based Racetrack Memo...

Spin trapping electron paramagnetic resonance (EPR) method is a method that combines the spin-trapping technique with the EPR technique to detect short-lived free radicals.     Why Use Spin Trapping Technology?Free radicals are atoms or groups with unpaired electrons formed by the covalent bonding of compound molecules under external conditions such as heat and light. They are widely found in nature.With the development of interdisciplinary disciplines such as biology, chemistry, and medicine, scientists have found that many diseases are associated with free radicals. However, due to their active and reactive nature, the free radicals generated in the reactions are often unstable at room temperature and difficult to be detected directly using conventional EPR spectroscopy methods.    Although short-lived free radicals can be studied by time-resolved EPR techniques or low-temperature fast-freezing techniques, their lower concentrations for most free radicals in biological systems limit the implementation of the above techniques. The spin trapping technique, on the other hand, allows the detection of short-lived free radicals at room temperature through an indirect method.     Fundamentals of Spin Trapping Technology   In a spin-trapping experiment, a spin trap (an unsaturated antimagnetic substance capable of trapping free radicals) is added to the system. After adding the spin trap, the unstable radicals and the trap will form more stable or longer-lived spin adducts. By detecting the EPR spectra of the spin adducts and processing and analyzing the data, we can invert the type of radicals and thus indirectly detect the unstable free radicals.     Figure 1 Principle of spin capture technique (DMPO as an example)     Selection of Spin Trap   The most widely used spin traps are mainly nitrone or nitroso compounds, typical spin traps are MNP (2-methyl-2-nitrosopropane dimer), PBN (N-tert-butyl α-phenyl nitrone), DMPO (5,5-dimethyl-1-pyrroline-N-oxide), and the structures are shown in Figure 2. And an excellent spin trap needs to satisfy three conditions.   1. Spin adducts formed by spin traps with unstable free radicals should be stable in nature and long-lived. 2. The EPR spectra of spin adducts formed by spin traps and various unstable radicals should be easily distinguishable and identifiable. 3. Spin trap is easy to react specifically with a variety of free radicals, and there is no side reaction. Based on the above conditions, the spin trap widely used in various industries is DMPO.     Figure 2 Schematic chemical structure of MNP, PBN, DMPO   Table 1 Comparison of common spin traps     Common Types of Spin-trapping Free Radicals   In spin trapping experiments, the most common ones are O- and N-centered radicals, such as reactive oxygen species (ROS) and reactive nitrogen species (RNS), but not all ROS and RNS are free radical...

The electron paramagnetic resonance (EPR or ESR) technique is the only method available for directly detecting unpaired electrons in samples. Among them, the quantitative EPR (ESR) method can provide the number of unpaired electron spins in a sample, which is essential in studying the reaction kinetics, explaining the reaction mechanism and commercial applications. Therefore, obtaining the unpaired electron spin numbers of samples by electron paramagnetic resonance techniques has been a hot topic of research.  Two main quantitative electron paramagnetic resonance methods are available: relative quantitative EPR (ESR) and absolute quantitative EPR (ESR).     Relative Quantitative EPR (ESR) Method   The relative quantitative EPR method is accomplished by comparing the integrated area of the EPR absorption spectrum of an unknown sample with the integrated area of the EPR absorption spectrum of a standard sample. Therefore, in the relative quantitative EPR method, a standard sample with a known number of spins needs to be introduced. The size of the integrated area of the EPR absorption spectrum is not only related to the number of unpaired electron spins in the sample, but also to the settings of the experimental parameters, the dielectric constant of the sample, the size and shape of the sample, and the position of the sample in the resonant cavity. Therefore, to obtain more accurate quantitative results in the relative quantitative EPR method, the standard sample and the unknown sample need to be similar in nature, similar in shape and size, and in the same position in the resonant cavity.   Quantitative EPR Error Sources     Absolute Quantitative EPR (ESR) Method   The absolute quantitative EPR method means that the number of unpaired electron spins in a sample can be obtained directly by EPR testing without using a standard sample. In absolute quantitative EPR experiments, to obtain the number of unpaired electron spins in a sample directly, the value of the quadratic integral area of the EPR spectrum (usually the first-order differential spectrum) of the sample to be tested, the experimental parameters, the sample volume, the resonance cavity distribution function and the correction factor are needed. The absolute number of unpaired electron spins in the sample can be directly obtained by first obtaining the EPR spectrum of the sample through the EPR test, then processing the EPR first-order differential spectrum to obtain the second-integrated area value, and then combining the experimental parameters, sample volume, resonant cavity distribution function and correction factor.   CIQTEK Electron Paramagnetic Resonance Spectroscopy   The absolute quantification of unpaired electron spins of the CIQTEK EPR (ESR) spectroscopy can be used to obtain the spin number of unpaired electrons in a sample directly without the use of a reference or standard sample. The resonant cavity distribution funct...

Electron spin sensors have high sensitivity and can be widely used to probe various physicochemical properties, such as electric field, magnetic field, molecular or protein dynamics, and nuclear or other particles. These unique advantages and potential application scenarios make spin-based sensors a hot research direction at present. Sc3C2@C80 has a highly stable electron spin protected by a carbon cage, which is suitable for gas adsorption detection within porous materials. Py-COF is a recently emerged porous organic framework material with unique adsorption properties, which was prepared using a self-condensing building block with a formyl group and an amino group. prepared with a theoretical pore size of 1.38 nm. Thus, a metallofullerene Sc3C2@C80 unit (~0.8 nm in size) can enter one of the nanopores of Py-COF.   A nanospin sensor based on metal fullerene was developed by Taishan Wang, a researcher at the Institute of Chemistry, Chinese Academy of Sciences, for detecting gas adsorption within a porous organic framework. The paramagnetic metal fullerene, Sc3C2@C80, was embedded in the nanopores of a pyrene-based covalent organic framework (Py-COF). The adsorbed N2、CO、CH4、CO2、C3H6 and C3H8 within the Py-COF embedded with the Sc3C2@C80 spin probe were recorded using the EPR technique ( CIQTEK EPR200-Plus).It was shown that the EPR signals of the embedded Sc3C2@C80 regularly correlated with the gas adsorption properties of the Py-COF. The results of the study were published in Nature Communications under the title "Embedded nano spin sensor for in situ probing of gas adsorption inside porous organic frameworks".     Probing gas adsorption properties of Py-COF using molecular spin of Sc3C2@C8     In the study, the authors used a metallofullerene with paramagnetic properties, Sc3C2@C80 (~0.8 nm in size), as a spin probe embedded into one nanopore of pyrene-based COF (Py-COF) to detect gas adsorption within Py-COF. Then, the adsorption properties of Py-COF for N2、CO、CH4、CO2、C3H6 and C3H8 gases were investigated by recording the embedded Sc3C2@C80 EPR signals. It is shown that the EPR signals of Sc3C2@C80 regularly follow the gas adsorption properties of Py-COF. And unlike conventional adsorption isotherm measurements, this implantable nanospin sensor can detect gas adsorption and desorption by in situ real-time monitoring. The proposed nanospin sensor was also used to probe the gas adsorption properties of metal-organic framework (MOF-177), demonstrating its versatility.     Relationship between gas adsorption properties and EPR signals     Effect of gas pressure on EPR signal     EPR signal line width analysis   Spin-based sensors have attracted considerable attention owing to their high sensitivities. Herein, we developed a metallofullerene-based nano spin sensor to probe gas adsorption within porous organic frameworks. For this, spin-...

Hydrogen energy is the clean energy that drives the transformation from traditional fossil energy to green energy. Its energy density is 3 times that of oil and 4.5 times that of coal! It is the disruptive technology direction of the future energy revolution. The hydrogen fuel cell is the key carrier to realize the conversion of hydrogen energy into electric energy, and countries around the world attach great importance to the development of hydrogen fuel cell technology. This has put forward higher requirements on materials, process technology, and characterization means of hydrogen energy and hydrogen fuel cell industry chain. Gas adsorption technology is one of the important methods for material surface characterization, and plays a crucial role in the utilization of hydrogen energy mainly in hydrogen fuel cells.   Application of gas adsorption technology for characterization in the hydrogen production industryHow to produce hydrogen is the first step in harnessing hydrogen energy. Hydrogen production from electrolytic water with high purity grade, low impurity gas, and easy to combine with renewable energy sources is considered the most promising green hydrogen energy supply in the future [1].To improve the efficiency of hydrogen production from electrolytic water, the development and utilization of high-performance HER electrode catalysts is a proven way.  Porous carbon materials represented by graphene have excellent physicochemical properties, such as rich pore structure, large specific surface area, high electrical conductivity, and good electrochemical stability, which bring new opportunities for the construction of efficient composite catalytic systems. The hydrogen precipitation capacity is enhanced using co-catalyst loading or heteroatom doping [2].   In addition, a large number of studies have shown that the catalytic activity of HER electrode catalysts depends largely on the number of active sites exposed on their surfaces and the more active sites exposed, the better their corresponding catalytic performance. The larger specific surface area of porous carbon material, when used as a carrier, will to a certain extent expose more active sites to the active material and accelerate the reaction of hydrogen production.   The following are examples of the characterization of graphene materials using CIQTEK V-Sorb X800 series specific surface and pore size analyzer. From Figure 1, it can be seen that the surface area of graphene prepared by different processes has a large difference of 516.7 m2/g and 88.64 m2/g, respectively. Researchers can use the results of the specific surface area test to make a judgment of the basic catalytic activity, which can provide a corresponding reference for the preparation of composite catalysts.     Fig. 1 Test results of the specific surface area of graphene synthesized by different processes   In addition, many researchers have improved the electrocatalytic ac...

Did you know that light can create sound? In the late 19th century, scientist Alexander Graham Bell (considered one of the inventors of the telephone) discovered the phenomenon of materials producing sound waves after absorbing light energy, known as the photoacoustic effect.   Alexander Graham Bell Image Source: Sina Technology   After the 1960s, with the development of weak signal detection technology, highly sensitive microphones and piezoelectric ceramic microphones appeared. Scientists developed a new spectroscopic analysis technique based on the photoacoustic effect - photoacoustic spectroscopy, which can be used to detect substances of samples and their spectroscopic thermal properties, becoming a powerful tool for physicochemical research in inorganic and organic compounds, semiconductors, metals, polymer materials, etc.     How can we make light create sound?As shown in the figure below, a light source modulated by a monochromator, or a pulsed light such as a pulsed laser, is incident on a photoacoustic cell. The material to be measured in the photoacoustic cell absorbs light energy, and the absorption rate varies with the wavelength of the incident light and the material. This is due to the different energy levels of the atomic molecules constituted in the different materials, and the absorption rate of light by the material increases when the frequency ν of the incident light is close to the energy level hν. The atomic molecules that jump to higher energy levels after absorbing light do not remain at the higher energy levels; instead, they tend to release energy and relax back to the lowest ground state, where the released energy often appears as thermal energy and causes the material to expand thermally and change in volume.When we restrict the volume of a material, for example, by packing it into a photoacoustic cell, its expansion leads to changes in pressure. After applying a periodic modulation to the intensity of the incident light, the temperature, volume, and pressure of the material also change periodically, resulting in a detectable mechanical wave. This oscillation can be detected by a sensitive microphone or piezoelectric ceramic microphone, which is what we call a photoacoustic signal.   Principle Schematic     How does a lock-in amplifier measure photoacoustic signals?   In summary, the photoacoustic signal is generated by a much smaller pressure signal converted from very small heat (released by atomic or molecular relaxation). The detection of such extremely weak signals necessarily cannot be done without lock-in amplifiers.   In photoacoustic spectroscopy, the signal collected from the microphone needs to be amplified by a preamplifier and then locked to the frequency signal we need by a lock-in amplifier. In this way, a high signal-to-noise ratio photoacoustic spectroscopy signal can be detected and the properties of the sample can be measured.   CIQTEK has launc...