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-conductivity material method, also known as the induced magnetic field method, works by enclosing a finite space with high-conductivity materials. The environmental magnetic field acts on the shielding material through its electric field component, inducing an electromotive force, which in turn generates an induced current and an induced magnetic field. Based on the fundamental principles of electromagnetics, this induced magnetic field is equal in magnitude (slightly smaller due to resistance) and opposite in direction to the original magnetic field (with a slight phase lag). Thus, the magnetic field within the finite space is counteracted and weakened, achieving demagnetization.

Further understanding of the induced magnetic field method can be gained by considering the operation of a three-phase induction motor, which provides insights into the working principles of induced magnetic fields. It is important to note that an asynchronous squirrel cage motor cannot achieve the rotating magnetic field (50Hz × 60s = 3000 RPM) because the squirrel cage bars cannot cut magnetic lines, thus preventing the generation of induced currents, induced magnetic fields, and driving force.

The effectiveness of the induced magnetic field method is independent of the thickness of the shielding material within a certain range.

C. Common characteristics of both methods: Full penetration welding is required, and the height of the weld seam should not be less than the thickness of the shielding material. Attention must be paid to the design of openings at various scales and waveguide ports. Whether the design/production is successful will greatly affect the shielding effectiveness (applying the "Weakest Link" theory to shielding). It is also important to note that the vibration of the electron microscope in the shielding room should not exceed that of the surrounding environment (there have been cases where the magnetic field passed the inspection but the vibration increased compared to the original, causing non-compliance).

From their basic working principles, it is evident that both the magnetic circuit diversion method and the induced magnetic field method are ineffective for DC fields. They are also generally ineffective for near-DC fields (in such cases, an active demagnetizer is necessary to improve near-DC electromagnetic interference).

A．Compare the two methods in a table:

Upon careful analysis, the magnetic circuit diversion method is more advantageous. The passive low-frequency demagnetizer has advantages such as small size, lightweight, low cost, no impact on the environment, and the possibility of post-purchase installation.

However, one important point to note is that magnetic shielding is often an "entrusted" project, meaning that it often includes electrical, water, air conditioning, lighting, and network systems, as well as monitoring, during the construction process. Therefore, if there is a need for remodeling, it offers a higher cost-performance ratio.

Overall, passive magnetic shielding has better effectiveness than demagnetizers, but due to the aforementioned reasons, demagnetizers may still be the only option in some environments.

For Scanning Electron Microscope, the difference between these methods is not significant. However, for Transmission Electron Microscope, it is recommended to use magnetic shielding as much as possible, as the requirements for magnetic fields are generally higher compared to Scanning Electron Microscope.

NFC (Near Field Communication) technology has revolutionized the way we interact with digital devices, making tasks such as mobile payments, access control, and data sharing more convenient than ever. In this blog post, we will delve into the applications of NFC tags equipped with Mifare Ultralight chips, highlighting their versatility and potential uses across various industries.

What is Mifare Ultralight Chip? Mifare Ultralight is a type of RFID chip developed by NXP Semiconductors, offering a cost-effective and efficient solution for implementing NFC technology. The Mifare Ultralight chip does not require a power source, making it ideal for passive applications where the tag is activated by an NFC reader's electromagnetic field.

Applications of NFC Tags with Mifare Ultralight Chip:

1. Access Control: NFC tags with Mifare Ultralight chips can be used for secure access control systems in offices, residential buildings, and events. By simply tapping an NFC-enabled device or card on the tag, users can gain entry to restricted areas.

2. Smart Posters and Marketing: NFC tags embedded with Mifare Ultralight chips can transform traditional posters and advertisements into interactive experiences. Users can tap their smartphones on the tag to access product information, promotional offers, or multimedia content.

3. Public Transport Ticketing: NFC tags with Mifare Ultralight chips are utilized in contactless ticketing systems for public transportation. Commuters can easily tap their NFC-enabled cards or devices on the tag to pay for fares and access transportation services.

4. Inventory Management: NFC tags with Mifare Ultralight chips are employed in inventory tracking and management systems across industries. By tagging products and assets with NFC-enabled labels, businesses can streamline inventory processes and enhance traceability.

5. Event Ticketing and Registration: Event organizers leverage NFC tags with Mifare Ultralight chips for efficient ticketing and attendee registration. Guests can quickly check-in by tapping their NFC-enabled tickets or badges on the tag, reducing waiting times and enhancing the overall event experience.

Unirfid specializes in providing NFC tags, cards, and wristbands with Mifare ultralight chip, offering a comprehensive solution for variaous options.

Related Products: NFC Tags with Mifare Ultralight chip, NFC Cards with Mifare ultralight chip, NFC Silicone Wristands with Mifare Ultralight chip

Capacitive and resistive touchscreens are two common technologies used in touchscreen devices, each with its own principles of operation:

Capacitive Touchscreen:

Capacitive touchscreens work based on the electrical properties of the human body. They are made of layers of glass coated with a conductive material like indium tin oxide (ITO).

When you touch a capacitive touchscreen with your finger (which is conductive), it disrupts the screen's electrostatic field, causing a change in capacitance at the point of contact.

The device detects this change in capacitance and calculates the touch point. This technology allows for multi-touch gestures (e.g., pinch-to-zoom) because it can detect multiple points of contact simultaneously.

Capacitive touchscreens are generally more responsive and durable than resistive touchscreens. They are commonly used in smartphones, tablets, and other modern touchscreen devices.

Resistive Touchscreen:

Resistive touchscreens consist of several layers, typically two flexible sheets separated by a small gap. The inner surface of each layer is coated with a resistive material, and the outer layers are conductive.

When you press on a resistive touchscreen, the two layers come into contact at the point of touch, creating a circuit. This changes the electrical current running through the screen.

The device detects this change in electrical current and calculates the touch point. Resistive touchscreens typically only support single-touch input.

Resistive touchscreens are less expensive to produce compared to capacitive touchscreens, but they are generally less responsive and have poorer visibility because of the additional layers.

They are commonly found in older devices such as some GPS units, industrial control panels, and certain types of kiosks.

In summary, capacitive touchscreens rely on changes in capacitance to detect touch, while resistive touchscreens rely on changes in electrical resistance. Each technology has its own advantages and is suitable for different types of applications.

As technology evolves, Thin Film Transistor Liquid Crystal Display (TFT LCD) modules are becoming the backbone of digital displays, valued for their sharp resolution, fast response times, and vivid color accuracy. TFT LCDs are widely used across industries, including consumer electronics, automotive interfaces, industrial equipment, and medical devices, making them a versatile solution in today’s digital world.

Understanding TFT LCD Technology

A TFT LCD display is a type of LCD that uses thin-film transistor technology to enhance image quality. This technology arranges pixels in a matrix, where each pixel is individually controlled, allowing for higher contrast ratios and better color depth. Unlike traditional LCD displays, TFT technology significantly reduces “ghosting” effects, making it ideal for applications requiring smooth, high-speed graphics.

Key Components of TFT LCD Modules

TFT LCD modules are crafted with multiple layers. These generally include the TFT glass panel, the backlight unit (BLU), and control circuitry. The TFT layer governs each pixel’s behavior, allowing for fine-tuned brightness and color management, while the backlight provides consistent illumination across the display. This layering creates a vibrant visual experience with precise control over color and brightness, making TFT LCDs a top choice for applications demanding clarity and responsiveness.

Advantages of TFT LCD Displays

Enhanced Image Quality: TFT technology allows for high-resolution displays with vibrant colors and deep contrast, ensuring sharp visuals.

Fast Refresh Rates: Ideal for moving images, TFT modules minimize lag, providing a seamless experience for video playback and graphic applications.

Wide Application Range: From mobile devices and cameras to industrial machinery, TFT LCDs adapt well to diverse environments and uses.

Golden Vision Optoelectronic: Leading TFT LCD Manufacturer

As a one-stop LCD and LCM provider, Golden Vision Optoelectronic Co., Ltd is dedicated to developing and manufacturing advanced TFT LCD modules. Our modules meet international standards and are certified for quality (ISO9001, IATF16949) and environmental compliance (ISO14001, RoHS). With a robust infrastructure and a commitment to innovation, we aim to deliver TFT solutions that cater to both emerging and established market needs.

Choosing the Right TFT LCD Module

When selecting a TFT LCD, consider factors like resolution, viewing angle, and environment. Golden Vision Optoelectronic offers a wide variety of TFT LCD options, customizable to your application’s needs, ensuring both functionality and reliability in any setting.

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 middle-upper part of the column or near the electron gun (as the electron beam emitted from the electron gun may have a slow speed, making it more prone to magnetic field interference). During the initial installation, the detector can be tested at multiple positions to determine the most effective location for fixation.

The demagnetization coils usually adopt a "large coil" design, where six coils are fixed on various walls, ceilings, and floors of the room as far apart as possible. Alternatively, rectangular frames with embedded coils can be customized. However, the "frame" design is less common except for cleanrooms or large rooms. This is because the demagnetization effect is slightly inferior, and it can interfere with the operation and usage of Electron Microscopes.

From the basic working principle of the demagnetizer, the following conclusions can be drawn:

1) Due to the inherent hysteresis that is difficult to eliminate, there will always be a phase difference between the anti-phase magnetic field and the ambient interference magnetic field, limiting the demagnetization effectiveness.

2) In the three-dimensional space enclosed by the demagnetization coils, the demagnetized magnetic field is not uniform. It gradually deteriorates from the center of the detector towards the outer surface, as the magnetic field intensity is inversely proportional to the square of the distance from the signal source (i.e., the demagnetization coils). Moreover, the uniformity of the ambient magnetic field is generally superior to that generated by the demagnetizer, resulting in a reduced demagnetization effect as the distance from the center of the detector increases.

3) This phenomenon particularly affects the use of demagnetizers in Scanning Electron Microscope rather than Transmission Electron Microscope.

Multifunctional Applications of Biometric Tablets in Modern Technology

In an era where security and efficiency are paramount, the integration of biometrics into portable devices has revolutionized industries. One such innovation is the biometric tablet, a device that combines advanced biometric scanning capabilities with powerful computing capabilities. This blog explores the uses of biometric tablets, focusing specifically on models with IP68 standards, FBI-certified fingerprint scanners, and a powerful set of specs.

Learn about biometric tablets

Biometric fingerprint tablets are specialized devices that utilize biometric authentication methods, such as fingerprint scanning, to enhance security and simplify operations. These tablets are particularly useful in areas where data integrity and user authentication are critical, such as healthcare, finance and law enforcement. The incorporation of biometric technologies not only ensures secure access to sensitive information but also facilitates efficient data management and transaction processing.

Key Features of Biometric Tablets

This biometric tablet is designed to meet the stringent requirements of a variety of professional environments. Compliant with IP68 standard, dustproof and waterproof, suitable for use in harsh conditions. This durability is critical for field work, where exposure to harsh environments can impair the functionality of standard equipment.

The tablet comes with an FBI-certified fingerprint scanner, providing a high level of security. This certification demonstrates that the device meets strict biometric performance standards, ensuring user authentication is reliable and accurate. This feature is particularly beneficial in sectors such as law enforcement, where secure access to sensitive data is critical.

The tablet’s connectivity options are extensive, with 5G network capabilities for fast data transfer and communication. This is critical for professionals who need real-time access to information, such as medical personnel in emergencies or field agents conducting investigations. In addition, the device also includes a rich set of ports such as HDMI, RJ45, RJ232 and Lora, allowing seamless integration with a variety of peripherals and systems.

In terms of performance, the tablet is powered by an octa-core 2.4GHz CPU, ensuring that it can handle demanding applications and multitasking with ease. This processing power is critical for professionals who rely on complex software for data analysis, reporting or real-time monitoring.

Another noteworthy feature is the removable battery with a capacity of up to 10,000mAh. This allows for extended use without the need for frequent charging, making it ideal for professionals who travel frequently or work in remote areas.

 Biometric Tablet Application

The applications for biometric tablets are wide and varied. In healthcare, for example, these devices can be used for patient identification, ensuring medical records are accurately matched to the correct individual. This not only improves patient safety but also streamlines administrative processes.

In the financial sector, biometric tablets can facilitate secure transactions and account access, reducing the risk of fraud. The combination of biometric authentication and high-speed connectivity ensures financial institutions can operate efficiently while maintaining strict security measures.

Law enforcement agencies can utilize biometric tablets for field operations, allowing officers to access databases and verify identities on the spot. This capability can significantly increase the effectiveness of investigations and improve public safety.

In summary, biometric tablets represent a significant advancement in portable technology, offering a combination of security, performance and versatility. With features such as IP68 protection, biometric police tablet, and powerful processing capabilities, these devices are ideal for a variety of professional applications. As the industry continues to evolve and prioritize security and efficiency, biometric tablet adoption is likely to increase, paving the way for a more secure and streamlined future.

By any metric, the New York Marathon is an immense production. The 50,000+ runners who make this the world's largest marathon. Their route will take them through all five of the city's boroughs, from the starting line on Staten Island up through Brooklyn and Queens, across the Queensboro Bridge to Manhattan's Upper East Side, north into the Bronx and then back down along the east side of Central Park to the finish line in the Park itself.

Ensuring that the whole thing goes off without a hitch is a remarkable feat of organization. The race relies on a small army of volunteers, who do everything from staffing the water stations at every mile marker and making sure runners don't get lost to offering medical expertise.

Donni Katzovicz is a ham radio enthusiast who has volunteered at the Marathon since 2018 through Event Hams, a group that has coordinated the Marathon's use of amateur radio for the last decade. He explains that ham radio essentially plays two key roles during the marathon.

The first is as a route for communications that don’t require the use of official channels. “Obviously,” he says, “The marathon has commercial 2 way radio licenses and its own communications infrastructure. You also have all the local emergency services—FDNY, NYPD, EMS. And they all have their own radios and equipment.”

At the most basic level, ham radio is any radio that operates on the radio bands reserved for amateurs. As Katzovicz explains, enthusiasts come up with all manner of uses for their little corner of the electromagnetic spectrum: “The hobby itself is really, really, incredibly broad and encompasses a lot of different parts of science and technology. Some people … have handheld walkie talkies and to talk to other licensed people in their neighborhood; others make their own radios or make their own Rube Goldberg-esque devices to listen and transmit, and others coordinate with local civil bodies and provide backup communications.”

In a scenario where, say, all a city’s power was out, battery-powered walkie talkies would still work just fine, whereas cell phones would be useless.

Ham radio enthusiasts from throughout the region were at the Polk County Fairgrounds on Saturday, drawn by the lure of the semi-annual swap meet.

For some, ham radio is a hobby. Hams tends to use two kinds of gear: HF and VHF/UHF. HF gear is made to talk over long distances, while VHF/UHF radio is for talking around town. But for Kjell Lindgren, it was an out-of-this-world experience.

Ham radios work when other forms of communication don't. "(That's) huge, especially with the first one (Helene) that went through North Carolina. You could listen on the radio. They were able to facilitate getting aid to a lot of people,” said Josh Scott, Yamhill County Amateur Radio Emergency Services Group. “And in those events, there were people getting on their radio that weren't licensed. But they were still able to get on the Frs two way radio and ask for help.”

Oregon isn't home to major hurricanes. But local residents have their own worries. Fires, for example, and a ticking time bomb off the coast.

“If the Cascadia earthquake were to hit, the reality is that we will probably not have cell phones or telephones of any sort. The Internet will be down,”Scott said. "The only way you're going to be able to communicate after Cascadia is with radios.”

“Ham radios used to be more popular. Most of the people in their 70s and 80s were part of ham radio clubs and got their licenses. This was in almost every school,” she said. “Now, there’s a lot less of that going on. It’s a great hobby. But it’s going to be very valuable when the big one hits.”