Applications

First, let's discuss the causes of low-frequency vibrations. Repeated tests have shown that low-frequency vibrations are primarily caused by the resonances of the building. The construction specifications for industrial and civil buildings are generally similar in terms of floor height, depth, span, beam and column sections, walls, floor beams, raft slabs, etc. Although there may be some differences, particularly regarding low-frequency resonances, common characteristics can be identified. Here are some patterns observed in building vibrations: 1. Buildings with linear or point-shaped floor plans tend to exhibit larger low-frequency resonances, while those with other shapes such as T, H, L, S, or U have smaller resonances. 2. In buildings with linear floor plans, vibrations along the long axis are often more pronounced than those along the short axis. 3. In the same building, the first floor without a basement typically experiences the smallest vibrations. As the floor height increases, the vibrations worsen. The vibrations in the first floor of a building with a basement are similar to those in the second floor, and the lowest vibrations are typically observed in the lowest level of the basement. 4. Vertical vibrations are generally larger than horizontal vibrations and are independent of the floor level. 5. Thicker floor slabs result in smaller differences between vertical and horizontal vibrations. In the majority of cases, vertical vibrations are larger than horizontal vibrations. 6. Unless there is a significant vibration source, vibrations within the same floor of a building are generally consistent. This applies to locations in the middle of a room as well as those near walls, columns, or overhead beams. However, even if measurements are taken at the same location without any movement and with a few minutes interval, the values are likely to differ. Now that we know the sources and characteristics of low-frequency vibrations, we can take targeted improvement measures and make advanced assessments of the vibration conditions in certain environments. Improving low-frequency vibrations can be costly, and sometimes it is not feasible due to environmental constraints. Thus, in practical applications, it is often advantageous to choose or relocate to a better site for operating an electron microscope laboratory. Next, let's discuss the impact of low-frequency vibrations and potential solutions. Vibrations below 20 Hz have a significant disruptive effect on electron microscopes, as depicted in the following figures.   Image 1   Image 2 Image 1 and Image 2 were taken by the same Scanning Electron Microscope (both at 300kx magnification). However, due to the presence of vibration interference, Image 1 has noticeable jaggedness in the horizontal direction (in segments), and the clarity and resolution of the image are significantly reduced. Image 2 is the result obtained from the same sample after eliminating the vibration interference...

The environment of an electron microscopy lab does not directly impact the electron microscope itself but rather affects the imaging quality and overall performance of the microscope. During the operation of an electron microscope, the fine electron beam needs to travel in a high vacuum environment, covering a distance of 0.7 meters (for Scanning Electron Microscope) to over 2 meters (for Transmission Electron Microscope). Along the path, external factors such as magnetic fields, ground vibrations, noise in the air, and airflows can cause the electron beam to deviate from its intended path, leading to a degradation in imaging quality. Therefore, specific requirements need to be met for the surrounding environment.   Passive low-frequency electromagnetic shielding primarily involves two methods, which differ in the shielding material used: one method uses high-permeability materials (such as steel, silicon steel, and mu-metal alloys), and the other method uses high-conductivity materials (such as copper and aluminum). Although the working principles of these two methods are different, they both achieve effective reduction of environmental magnetic fields.   A. The high-permeability material method, also known as the magnetic circuit diversion method, works by enclosing a finite space (Region A) with high-permeability materials. When the environmental magnetic field strength is Ho, the magnetic reluctance of the high-permeability material is much smaller than that of air (common Q195 steel has a permeability of 4000, silicon steel ranges from 8000 to 12000, mu-metal alloys have a permeability of 24000, while air has an approximate value of 1). Applying Ohm's law, when Rs is much smaller than Ro, the magnetic field strength within the enclosed space (Region A) decreases to Hi, achieving demagnetization (see Figure 1 and Figure 2, where Ri represents the air reluctance within space A, and Rs represents the shielding material reluctance). Inside the shielding material, the magnetic domains undergo vibration and dissipate magnetic energy as heat under the action of the magnetic field.   Since silicon steel and mu-metal alloys exhibit anisotropy in permeability and cannot be hammered, bent, or welded during construction (although theoretically, heat treatment can improve these properties, it is impractical for large fixed products), their effective performance is significantly reduced. However, they can still be used for supplementary or reinforcement purposes in certain special areas without hammering, bending, or welding.   High-permeability materials are expensive, so they are generally not extensively used in electron microscope shielding and are only seen in a few specific areas (such as door gaps, waveguide openings, etc.).   The effectiveness of the magnetic circuit diversion method is roughly linearly related to the thickness of the shielding material, which can theoretically be infinitely thin.   B. The high-conduc...

The environment of an electron microscopy lab does not directly impact the electron microscope itself but rather affects the imaging quality and overall performance. During the operation of an electron microscope, the fine electron beam needs to travel in a high vacuum environment, covering a distance of 0.7 meters (for Scanning Electron Microscope) to over 2 meters (for Transmission Electron Microscope). Along the path, external factors such as magnetic fields, ground vibrations, noise in the air, and airflows can cause the electron beam to deviate from its intended path, leading to a degradation in imaging quality. Therefore, specific requirements need to be met for the surrounding environment.   The Active Low-frequency Demagnetization System, mainly composed of a detector, controller, and demagnetization coil, is a specialized device used to mitigate low-frequency electromagnetic fields from 0.001Hz to 300Hz, referred to as a Demagnetizer.   Demagnetizers can be categorized into AC and DC types based on their working ranges, and some models combine both types to meet different working environments. The advantages of low-frequency demagnetizers include their small size, lightweight, space-saving design, and the ability to be installed post-construction. They are particularly suitable for environments where it is difficult to construct magnetic shielding, such as cleanrooms.   Regardless of the brand, the basic working principles of demagnetizers are the same. They use a three-axis detector to detect electromagnetic interference signals, dynamically control and output anti-phase currents through a PID controller, and generate anti-phase magnetic fields with three-dimensional demagnetization coils (typically three sets of six quasi-Helmholtz rectangular coils), effectively neutralizing and canceling the magnetic field in a specific area, reducing it to a lower intensity level.   The theoretical demagnetization accuracy of demagnetizers can reach 0.1m Gauss p-p, or 10 nT, and some models claim even better accuracy, but this is only achievable at the center of the detector and cannot be directly measured by other instruments due to mutual interference at close distances or the "Equipotential Surface" phenomenon at greater distances.   Demagnetizers automatically adjust the demagnetization current based on changes in the environment. At times, the current can be significant. It is important to pay attention to the wiring layout when other sensitive instruments are in close proximity to avoid interference with their normal operation. For example, electron beam exposure devices have been affected by nearby operating magnetic field detectors.   The power consumption of the demagnetizer controller is generally around 250W to 300W.   The detector of the demagnetizer can be a combination type or an AC/DC separate type, and there is no significant difference in performance. It is generally fixed in the mid...

The environment of an electron microscopy lab does not directly impact the electron microscope itself but rather affects the imaging quality and overall performance of the microscope. During the operation of an electron microscope, the fine electron beam needs to travel in a high vacuum environment, covering a distance of 0.7 meters (for Scanning Electron Microscope) to over 2 meters (for Transmission Electron Microscope). Along the path, external factors such as magnetic fields, ground vibrations, noise in the air, and airflows can cause the electron beam to deviate from its intended path, leading to a degradation in imaging quality. Therefore, specific requirements need to be met for the surrounding environment.   As is well known, electromagnetic waves consist of alternating magnetic and electric fields. However, it is important to consider the frequency when measuring electromagnetic waves using either magnetic or electric fields. In practice, it is necessary to take the frequency into account.   At very low frequencies (as the frequency tends to zero, equivalent to a DC magnetic field), the magnetic component of the electromagnetic wave becomes stronger while the electric component weakens. As the frequency increases, the electric component strengthens and the magnetic component decreases. This is a gradual transition without a distinct turning point. Generally, from zero to a few kilohertz, the magnetic field component can be well characterized, and units such as Gauss or Tesla are used to measure the field strength. Above 100 kHz, the electric field component is better measured, and the unit used for field strength is volts per meter (V/m). When dealing with a low-frequency electromagnetic environment with a strong magnetic field component, reducing the magnetic field directly is an effective approach.   Next, we will focus on the practical application of shielding a low-frequency (0-300 Hz), electromagnetic field with a magnetic field strength ranging from 0.5 to 50 milligauss (peak-to-peak) in a shielded volume of 40-120 cubic meters. Considering cost-effectiveness, the shielding material used is typically low-carbon steel plate Q195 (formerly known as A3).   Since the eddy current loss of a single thick material is greater than that of multiple thin layers (with the same total thickness), thicker single-layer materials are preferred unless there are specific requirements. Let's establish a mathematical model:   1. Derivation of the formula Since the energy of low-frequency electromagnetic waves is mainly composed of magnetic field energy, we can use high-permeability materials to provide magnetic bypass paths to reduce the magnetic flux density inside the shielding volume. By applying the analysis method of parallel shunt circuits, we can derive the calculation formula for the parallel shunting of magnetic flux paths. Here are some definitions: Ho: External magnetic field strength Hi: Magnetic field strength ins...

CIQTEK FIB-SEM Practical Demonstration   Focused Ion Beam Scanning Electron Microscope (FIB-SEM) are essential for various applications such as defect diagnosis, repair, ion implantation, in-situ processing, mask repair, etching, integrated circuit design modification, chip device fabrication, maskless processing, nanostructure fabrication, complex nano-patterning, three-dimensional imaging and analysis of materials, ultra-sensitive surface analysis, surface modification, and transmission electron microscopy specimen preparation.   CIQTEK has introduced the FIB-SEM DB550, which features an independently controllable Field Emission Scanning Electron Microscope (FE-SEM) with Focused Ion Beam (FIB) Columns. It is an elegant and versatile nanoscale analysis and specimen preparation tool that adopts “SuperTunnel” electron optics technology, low aberration, and non-magnetic objective design with low voltage and high-resolution capability to ensure the nano-scale analysis. The ion column facilitates a Ga+ liquid metal ion source with a highly stable, high-quality ion beam to ensure nano-fabrication capability. DB550 has an integrated nano-manipulator, gas injection system, electrical anti-contamination mechanism for the objective lens, and user-friendly GUI software, facilitating an all-in-one nanoscale analysis and fabrication workstation.   To showcase the outstanding performance of the DB550, CIQTEK has planned a special event called "CIQTEK FIB-SEM Practical Demonstration." This program will present videos demonstrating the broad applications of this cutting-edge equipment in fields such as materials science, the semiconductor industry, and biomedical research. Viewers will gain an understanding of the working principles of the DB550, appreciate its stunning microscale images, and explore the significant implications of this technology for scientific research and industrial development.   Nano-Micropillar Specimen Preparation  Nano-micropillar Specimen Preparation has been successfully achieved, demonstrating the powerful capabilities of the CIQTEK Focused Ion Beam Scanning Electron Microscope in nanoscale processing and analysis. The product's performance provides precise, efficient, and multimodal testing support for customers engaged in nanomechanical testing, facilitating breakthroughs in materials research.  

CIQTEK FIB-SEM Practical Demonstration Focused Ion Beam Scanning Electron Microscope (FIB-SEM) are essential for various applications such as defect diagnosis, repair, ion implantation, in-situ processing, mask repair, etching, integrated circuit design modification, chip device fabrication, maskless processing, nanostructure fabrication, complex nano-patterning, three-dimensional imaging and analysis of materials, ultra-sensitive surface analysis, surface modification, and transmission electron microscopy specimen preparation.   CIQTEK has introduced the FIB-SEM DB550, which features an independently controllable Field Emission Scanning Electron Microscope (FE-SEM) with Focused Ion Beam (FIB) Columns. It is an elegant and versatile nanoscale analysis and specimen preparation tool, that adopts “SuperTunnel” electron optics technology, low aberration, and non-magnetic objective design with low voltage and high-resolution capability to ensure the nano-scale analysis. The ion column facilitates a Ga+ liquid metal ion source with a highly stable, high-quality ion beam to ensure nano-fabrication capability. DB550 has an integrated nano-manipulator, gas injection system, electrical anti-contamination mechanism for the objective lens, and user-friendly GUI software, which facilitates an all-in-one nanoscale analysis and fabrication workstation.   To showcase the outstanding performance of the DB550, CIQTEK has planned a special event called "CIQTEK FIB-SEM Practical Demonstration." This program will present videos demonstrating the broad applications of this cutting-edge equipment in fields such as materials science, the semiconductor industry, and biomedical research. Viewers will gain an understanding of the working principles of the DB550, appreciate its stunning microscale images, and explore the significant implications of this technology for scientific research and industrial development.   Preparation of a transmission specimen of Ferrite-martensite steel   The FIB-SEM DB550 developed by CIQTEK possesses the capability to prepare transmission specimens of ferrite-martensite steel flawlessly. This capability enables researchers in the nanoscale domain to directly observe the interface characteristics, microstructural morphology, and evolution process of ferrite and martensite phases. These observations are crucial steps toward deepening the understanding of the relationship between phase transformation kinetics, microstructural organization, and mechanical properties of ferrite-martens steel.

From rich peanut oil to fragrant olive oil, edible vegetable oils enrich our diets and provide diverse nutritional benefits. With rising living standards and increasing oil consumption, ensuring the quality and safety of edible oils has become critical.   Using Electron Paramagnetic Resonance (EPR) to Evaluate Oil Quality EPR technology offers unique advantages: no sample pretreatment, non‑destructive, in‑situ, and highly sensitive. It is increasingly used in edible oil quality monitoring. EPR can detect unpaired electrons in oil molecules, which are early markers of oxidation. Oil oxidation is essentially a free radical chain reaction, producing radicals such as ROO·, RO·, and R·. By identifying these radicals, EPR allows scientific evaluation of oxidation level and stability before visible or sensory changes appear. This early detection is critical for preventing degradation caused by light, heat, oxygen exposure, or metal catalysts. Unsaturated fatty acids are particularly prone to oxidation, even at room temperature, which affects flavor, nutrition, and shelf life.   Benefits of using EPR for oil stability: Ensures safer, fresher edible oil for consumers. Guides effective antioxidant use. Supports quality control in oil‑containing foods. Extends product shelf life.   Thus, EPR technology provides a direct, sensitive, and non‑destructive approach to monitor edible oil quality, safeguarding public health.   Practical Applications of EPR in Oil Monitoring Principle During lipid oxidation, various free radicals are generated. These radicals are highly reactive and short-lived, so spin trapping is often used. Spin trapping agents (like PBN) react with unstable radicals to form stable radical adducts that EPR can detect reliably.   Application 1: Evaluating Oxidative Stability During each step of production, the free radical concentration can be measured, and the gradual changes in oxidation can be tracked. This allows for a precise determination of the product’s antioxidant capacity. For example, when PBN is used to trap radicals generated during peanut oil oxidation, stable radical adducts form. The EPR spectra of these adducts provide direct insight into oil oxidation. The stronger the EPR signal, the higher the free radical content, and the more oxidized the oil is. EPR spectra also reveal the effects of external factors, such as temperature. As temperature increases, the EPR signal intensity of radicals rises, indicating that higher temperatures accelerate oil oxidation.   Application 2: Assessing Antioxidant Effectiveness This study compares the effects of different antioxidants on the EPR signal intensity of peanut oil. Various antioxidants were added to the oil, including VE, BHT, BHA, a combination of BHA + BHT, and a combination of TBHQ + CA. As shown in the Figure, the Y-axis represents the spin concentration. Samples with added antioxidants show significantly lower spin signa...

Diffraction Limit Diffraction spots Diffraction occurs when a point light source passes through a circular aperture, creating a diffraction pattern behind the aperture. This pattern consists of a series of concentric bright and dark rings known as Airy discs. When the Airy discs of two point sources overlap, interference occurs, making it impossible to distinguish between the two sources. The distance between the centers of the Airy discs, which is equal to the radius of the Airy disc, determines the diffraction limit.   The diffraction limit imposes a limitation on the resolution of optical microscopes, preventing the resolvable distinction of objects or details that are too close together. The shorter the wavelength of light, the smaller the diffraction limit and the higher the resolution. Moreover, optical systems with a larger numerical aperture (NA) have a smaller diffraction limit and thus higher resolution. Airy discs The formula for calculating resolution,  NA represents the numerical aperture: Resolution（r） = 0.16λ /  NA   Throughout history, scientists have embarked on a long and challenging journey to surpass the diffraction limit in optical microscopes. From early optical microscopes to modern super-resolution microscopy techniques, researchers have continuously explored and innovated. They have attempted various methods, such as using shorter wavelength light sources, improving the design of objectives, and employing specialized imaging techniques.   Some important breakthroughs include:   1. Near-field scanning optical microscopy (NSOM): NSOM uses a probe placed close to the sample surface to take advantage of the near-field effect and achieve high-resolution imaging.   2. Stimulated emission depletion microscopy (STED): STED utilizes the stimulated emission depletion effect of fluorescent molecules to achieve super-resolution imaging.   3. Structured illumination microscopy (SIM): SIM enhances imaging resolution through specific illumination patterns and image processing algorithms.   4. Single-molecule localization microscopy (SMLM): SMLM achieves super-resolution imaging by precisely localizing and tracking individual fluorescent molecules.   5. Oil immersion microscopy: Immersing the objective lens in a transparent oil increases the numerical aperture in the object space, resulting in improved resolution.   6. Electron microscope: By substituting electron beams for light beams, electron microscopy takes advantage of the wave nature of matter according to the de Broglie principle. Electrons, having mass compared to photons, possess a smaller wavelength and exhibit less diffraction, enabling higher imaging resolution.   Inverted fluorescence microscope     CIQTEK 120kV Field Emission Transmission Electron Microscope TH-F120 These developments have allowed us to observe the microscopic world at a highe...