Typically, the cooling fan is connected to the system through a three-wire interface, which includes a power cable, a ground cable, and a Tach cable (speed signal cable). In order to be able to read Tach signals through GPIO, you need to select a fan that supports this feature. Such fans are often referred to as "ach-enabled" (supporting Tach) or "RPM-sensing" (supporting speed detection) fans.

The Tach signal is a pulse signal whose frequency is proportional to the speed of the fan. Typically, a pulse signal is generated for each rotational speed cycle. Here are some steps to help you implement a cooling fan that reads Tach signals via GPIO:

1, Make sure that the fan you choose supports Tach function or speed detection function. You can find this information in the fan specifications and instructions.

 

 

 

2. Connect the Tach wire of the fan to the available GPIO pin. This usually requires the use of cables or connectors.

 

 

 

3, Use the appropriate hardware interface circuit to convert the fan's Tach signal into a digital signal that can be read. This is because GPIO typically operates at the digital signal level.

 

 

 

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Scanning Electron Microscopy (SEM) is based on the principle of using a focused beam of high-energy electrons to probe the surface of a sample and produce a high-resolution detailed image.

 

Electron Source: SEM works by using an electron source, typically a heated tungsten filament or a field emission gun, to produce a beam of electrons.

 

Electron Beam Generation: The electron source emits electrons, which are accelerated to high energies by an electric field. The electrons are focused into a narrow beam using electromagnetic lenses.

 

Sample Interaction: The primary electron beam is directed onto the sample's surface. When the beam interacts with the sample, several types of interactions occur, including scattering, absorption, and emission of secondary electrons.

 

Scattering: The primary electrons may undergo elastic or inelastic scattering while interacting with the atoms in the sample. Elastic scattering results in a change in direction of the electron beam, while inelastic scattering leads to energy loss due to interactions with the sample's atoms.

 

Secondary Electron Emission: Some of the primary electrons knock off secondary electrons from the surface of the sample through inelastic scattering. These secondary electrons carry information about the sample's topography and composition.

 

Signal Detection: The emitted secondary electrons, along with other signals such as backscattered electrons and characteristic X-ray emissions, are detected using various detectors. Some common detectors in SEM are the Everhart-Thornley detector for secondary electrons and detectors for backscattered electrons or X-rays generated by the sample.

 

Image Formation: The detected signals are then amplified and processed to form an image. The signal intensity is typically converted into a grayscale or false-color representation, allowing the visualization of surface features and details.

 

Scanning: To generate a complete image, the electron beam is systematically scanned across the surface of the sample in a raster pattern. The intensity of the detected signals at each point is recorded, allowing the construction of a high-resolution image.

 

Image Display and Analysis: The final reconstructed image is displayed on a monitor or recorded for further analysis. SEM images can be used to examine the microstructure, morphology, elemental composition, and surface characteristics of a wide range of materials.

 

In short, scanning electron microscopy utilizes the interaction of a focused, high-energy electron beam with a sample to generate detailed images. By analyzing the signals emitted by the sample, SEM provides valuable information about the surface topography, morphology, and composition of the sample at high resolution. It is widely used in a variety of scientific and industrial applications for research, quality control, and materials characterization.

 

CIQTEK offers various high-quality SEM equipment for researchers and industrial users.

 

The Scanning Electron Microscope (SEM) is a powerful tool for various applications in material sciences, life sciences, and other fields. Different kinds of detectors have been developed to obtain more information and improve the performance of SEM. The following are a few common types of SEM detectors:

 

Backscattered Electron Detector (BSE): BSE detectors are used to detect electrons scattered by the nuclei of atoms and high atomic number elements within a substance.BSE detectors provide high-contrast images that can be used for compositional analysis of materials and characterization of microstructures.

 

Secondary Electron Detector (SE): The SE detector is used to detect secondary electrons on the surface of a material excited by a scanning electron beam. Since the surface morphology and material composition influence the secondary electrons, the SE detector provides a high-resolution image of the surface topography.

 

Transmission Electron Detector (TED): TED detectors are used to detect transmission electrons that pass through a thin sheet of material and are focused on the detector. TED detectors are suitable for high-resolution compositional and structural analyses of materials, e.g., atomic-level characterization of nanoparticles.

 

Energy Dispersive X-ray Spectroscopy (EDS): EDS detectors are used to analyze the elemental composition of materials. When a scanning electron beam interacts with a sample, characteristic X-rays are produced, and the EDS detector collects and measures the energy spectrum of these X-rays to determine the chemical composition and elemental distribution of the material.

 

Retarding Field Detector (RFD): The RFD detector is used to measure the charge carried by electrons generated on the surface of the sample. This type of detector is very useful for studying the electrical conductivity and surface charge properties of materials.

 

These are just some of the common SEM detectors; in fact, there are many other types of detectors, each with different advantages and applications. The selection of the appropriate detector depends on the objectives of the study and the information to be obtained.

 

CIQTEK's self-developed SEM offers a wide range of detectors to choose from, such as BSED, STEM, EDS, EDX, EBSD, In-lens, ETD, etc. 

 

ESR (Electron Spin Resonance) and EPR (Electron Paramagnetic Resonance) are used interchangeably to describe the same spectroscopic technique. The reason for the two different names can be traced to the historical development of the field and some of the interesting stories surrounding it.

 

Originally, the technique was called ESR, or electron spin resonance. It was discovered in the mid-20th century by physicists studying the behavior of electrons in magnetic fields. They observed that certain materials absorbed energy at specific frequencies when exposed to strong magnetic fields and subjected to electromagnetic radiation. This absorption is due to the electron spin states flipping in the magnetic field, resulting in resonance.

 

As the field grew, researchers began to study the spectra of paramagnetic species - atoms, molecules, or ions with unpaired electrons. They realized that ESR techniques could be used to study a wider range of systems than just electrons. As a result, the term EPR (Electron Paramagnetic Resonance) was coined to encompass a broader range of applications.

 

The transition from ESR to EPR did not happen overnight or with universal adoption. Different research groups and scientific communities preferred to use either term. For example, the term ESR was widely used in the United States, while EPR became popular in Europe. This difference in naming conventions continued for some time until the two terms gradually became synonymous. Today, the two terms are widely accepted and used interchangeably to describe the same spectroscopic techniques.

 

The dual naming of ESR and EPR provides insight into the historical development of the field and how scientific terminology has evolved and adapted over time. It also serves as a reminder that in science, different cultures and communities may adopt different names for the same concept, and these differences may persist until a consensus is reached.

 

EPR spectroscopy has applications in a variety of fields including chemistry, physics, biochemistry, materials science, and medicine. It has been used to study the structure of metalloproteins, the mechanism of enzyme reactions, the properties of organic radicals, the behavior of transition metal complexes, and defects in semiconductors, as well as many other fascinating areas of research. Its ability to probe electron spin makes it an invaluable tool for understanding the fundamental properties of paramagnetic systems and exploring their role in a variety of physical and chemical processes.

>> Check more about CIQTEK EPR spectroscopy.

To find the best price on an Electron Spin Resonance (ESR) spectroscopy, you can follow the steps below:

 

1. Explore search platforms

The most direct way is to search for “Electron Spin Resonance (ESR) spectroscopy best price” on major search engines like Google. Use words like cheap, sale, affordable, etc. to describe your needs, and it will be straightforward to find the right EPR spectroscopy at a recognized price, such as the one shown below:

 

2. Explore online B2B marketplaces

Check out online marketplaces that promote scientific instruments. These platforms allow users to find and compare prices for various scientific techniques, including ESR spectroscopy. Examples include GlobalSpec, DirectIndustry, etc. For example:

 

3. Request multiple quotes

When contacting agencies, EPR manufacturers, or vendors, request quotes from multiple sources. Provide them with specific details about the project, including sample type, sample size, data analysis needed, and any special requirements. Comparing multiple quotes will help you find the best price. Many EPR suppliers offer free, comprehensive, customized quotes, such as CIQTEK EPR.

 

4. Consider geographic location

The price of EPR Spectroscopy may vary by region or country. Sometimes, purchasing EPR Spectroscopy from a country with lower labor or equipment costs can result in significant cost savings. For example, CIQTEK's self-developed EPR Spectroscopy has the world's leading EPR technology to maintain high-quality service globally for any customized service and has a very competitive price.

 

5. Research Local Academic Institutions

Contact nearby universities, colleges, and research institutions to inquire about their ESR spectroscopy services. Academic institutions often offer advanced scientific equipment at reasonable prices, especially for researchers and students.

 

6. Collaborate with researchers

Consider collaborating with researchers who have access to ESR spectroscopy equipment. Many researchers are open to collaboration or offer their services at a discounted rate, especially if your project aligns with their interests. Attend scientific conferences, workshops, or networking events to connect with the relevant research community.

 

Keep in mind that while cost is an important factor, ensuring that the service provider delivers reliable, accurate results is also critical. Evaluate their technical expertise, reputation, and experience before deciding.

CIQTEK Scanning Electron Microscope (SEM) Competitive Advantage Analysis Report in terms of price, quality, and service:

 

Best Price:

CIQTEK SEM is competitively compared to other similar products on the market. The company offers a range of different models and specifications to meet the needs of different customers. By offering affordable options, CIQTEK appeals to customers looking for cost-effective solutions for their SEM microscopy needs.

 

High Quality:

CIQTEK is known for delivering high-quality scanning electron microscopes. The company uses advanced technology and ensures rigorous quality control in the manufacturing process. CIQTEK SEMs are designed to provide accurate and precise imaging, offer high resolution, and enable various imaging modes and analytical capabilities. The company's commitment to quality ensures that customers receive reliable and accurate results from their SEMs.

 

Great Service:

CIQTEK places great emphasis on customer service and support. The company has a dedicated team of trained professionals who provide technical assistance, installation support, and training to customers. CIQTEK offers prompt and efficient customer support to address any queries or issues that may arise during the lifetime of the SEM. This comprehensive support system enhances the overall customer experience and ensures that customers receive satisfactory after-sales service.

 

In summary, CIQTEK SEM has a competitive edge in the market due to its affordable pricing, high-quality imaging capabilities, and comprehensive customer service. These factors contribute to the company's ability to attract and retain customers in the increasingly competitive field of scanning electron microscopy.

Electron Paramagnetic Resonance (EPR) spectrometers are widely used in research institutions, universities, and industrial laboratories in South Korea. Major brands of EPR spectrometers in Korea include Jeol, Bruker, Nicolet, and CIQTEK. Below are the features and prices of these EPR companies.

 

Jeol

Features: Jeol is a time-honored brand known for its high-quality and reliable instruments. On the downside, the cost is relatively high compared to other brands. In addition, depending on the specific model, their instruments may have limited flexibility regarding modular configuration and specialized accessories.

 

Bruker

Features: Bruker is a well-known EPR spectrometer company. Their spectrometers are known for their high sensitivity, advanced signal processing capabilities, and ruggedness. However, it is costly and the complexity of the instrument software may require a learning curve for new users.

 

CIQTEK

CIQTEK EPR spectrometers are technologically advanced with world-leading resolution and sensitivity. Also featuring a user-friendly software interface that is easy to use for beginners, CIQTEK's wide range of EPR spectrometers is equipped with a variety of specialized accessories and options for versatility in experimental setups. It is more affordable. Saves time and budget.

  https://www.ciqtekglobal.com

 

Nicolet (Thermo Fisher Scientific)

Features: Nicolet EPR spectrometers from Thermo Fisher Scientific are renowned for their accuracy, reliability, and ease of use, with excellent signal-to-noise ratios and sensitivity for a wide range of EPR applications. They have excellent signal-to-noise ratios and sensitivity for a wide range of EPR applications. One potential drawback of Nicolet EPR spectrometers compared to other brands is their limited availability of specialized accessories and options, which may limit certain experimental setups or specific research needs.

 

It's worth noting that the prices mentioned above are rough estimates and can vary depending on the specific configuration and region. Additionally, each brand may offer different models with varying specifications and price ranges.

Electron paramagnetic resonance (EPR) spectroscopy is a powerful technique used to study the electronic structure of paramagnetic substances. It provides valuable insights into the nature and interactions of unpaired electrons in magnetic fields. Selection rules in EPR spectroscopy establish conditions that allow or prohibit leaps between different energy levels. Understanding these selection rules is essential for data interpretation and extracting meaningful information from EPR spectra.

 

Rotational selection rules in EPR

The most basic EPR spectroscopy selection rule is the spin selection rule. It states that for an electron jump to occur, the spin projection quantum number (m_s) must change by ±1. The m_s value describes the orientation of the electron spin for an external magnetic field. This shift can be caused by a spin flip (parallel to antiparallel or vice versa) or spin conservation (parallel to parallel or antiparallel to antiparallel).

 

Magnetic quantum number selection rules in EPR

The magnetic quantum number (m_l) selection rule is also important in EPR spectroscopy. It states that the change in m_l value due to transitions must be ±1. The m_l value is related to the component of angular momentum of the electron along the magnetic field axis. EPR leaps usually involve a change in the angular momentum of the electron orbitals, which results in a change in the m_l value.

 

Transition selection rules in EPR

Another important selection rule in EPR spectroscopy is the transition selection rule. It states that only allowed leaps will be observed in the EPR spectrum according to the spin and magnetic quantum number selection rules. No forbidden transitions that violate the selection rule will be detected. This rule facilitates the interpretation and assignment of spectral features.

 

Forbidden transitions in EPR

Although forbidden leaps strictly violate the selection rule, they sometimes occur with very low probability. Forbidden leaps are usually caused by weak interactions, such as spin-orbit coupling, which couples spin and orbital angular momentum. These leaps are usually observed as weaker spectral features compared to the allowed leaps.

 

Thus, selection rules play a key role in EPR spectroscopy, controlling the transitions between the energy levels of paramagnetic matter. Spin selection rules, magnetic quantum number selection rules, and lepton selection rules identify allowed and forbidden leaps that enable the interpretation and analysis of EPR spectra. Understanding these selection rules helps researchers extract valuable information about the electronic structure, spin dynamics, and magnetic properties of paramagnetic systems when using EPR spectroscopy.

CIQTEK EPR spectrometers are simple and easy to use, providing researchers with a user-friendly operating environment.

The g-value plays a crucial role in EPR (Electron Paramagnetic Resonance) spectroscopy in understanding the electronic structure and magnetic properties of paramagnetic substances. Today, we will talk about the key factor in EPR spectroscopy: the g-value (g-factor).

 

The g-value is a dimensionless quantity that represents a constant of proportionality between the magnetic field and the energy difference between the energy levels in the system. The g-value can be obtained by measuring the resonance frequency of a paramagnetic substance absorbing electromagnetic radiation in the presence of a magnetic field. It represents the extent to which the electron spin interacts with the external magnetic field. The g value is commonly used to determine important characteristics of paramagnetic substances, such as the number of unpaired electrons and their orbital angular momentum.

 

For a free electron, the g value is a constant of 2.0023, derived from fundamental physical properties. However, in more complex systems, such as transition metal complexes or organic radicals, the g value can deviate from this standard value. The deviation arises due to various factors, including spin-orbit coupling and hyperfine interactions with nearby nuclei. These interactions introduce additional energy levels and modify the electron's behavior in the magnetic field, leading to different g values.

 

By analyzing the g value in EPR spectroscopy, scientists can gain insights into the molecular structure and chemical environment of the paramagnetic species under investigation. A change in the g value can reveal the presence of different ligands or coordination environments around a metal ion, providing valuable information about the electronic configuration and coordination chemistry.

In addition, the g-value can be used to study the dynamics of a system. For example, it can provide information about the rate of electron transfer or spin relaxation processes, revealing the kinetics and mechanisms involved in chemical reactions or biological processes.

 

A common method of measuring the g-value is using EPR spectroscopy on a sample with a known g-value. This reference sample can be a compound with a well-characterized g-value or a spin probe, such as a stable organic radical. By comparing the position and shape of the resonance signals of the reference sample and the sample of interest, the g-value of the unknown species can be calculated.

 

Another approach involves calculating the g value from the Zeeman effect. The Zeeman effect describes the splitting of energy levels in a magnetic field. By measuring the magnetic field strength required to observe resonance at different frequencies, the g value can be derived using the equation g = hν/μBΔB, where h is Planck's constant, ν is the microwave frequency, μB is the Bohr magneton, and ΔB is the magnetic field difference between the resonance peaks.

 

In addition, the g value can be determined by analyzing the linewidth of the EPR signal. Since the g value depends on the orientation of the unpaired electrons in the magnetic field, any interaction or fluctuation in the environment will broaden the EPR signal. The g-value can be estimated by measuring the linewidth and analyzing its dependence on the magnetic field strength.

 

It is worth noting that the g value is not always a fixed constant. In some cases, it may vary due to factors such as electron-electron interactions or electrons leaving the domain. These variations can indicate the chemical or physical properties of the paramagnetic substance.

In summary, the g-value in EPR spectroscopy is an important parameter that helps characterize paramagnetic substances. By determining the g-value, researchers can gain valuable insights into the electronic structure and properties of paramagnetic compounds, contributing to understanding a wide range of scientific disciplines, including chemistry, physics, and biology.

 

Click here to read more application notes on EPR spectroscopy.

Electron paramagnetic resonance (EPR), also known as electron spin resonance (ESR), is a technique used to study the magnetic properties of materials containing unpaired electrons.

 

Here is a brief explanation of how electron paramagnetic resonance works:

 

Unpaired electrons: Many materials, such as transition metal ions or organic radicals, possess unpaired electrons. These unpaired electrons have intrinsic magnetic properties.

 

External magnetic field: A strong, static magnetic field is applied to the sample being studied. This field aligns the magnetic moments of the unpaired electrons in the sample.

 

Resonance condition: A microwave source emits electromagnetic radiation with a specific frequency, typically in the microwave range. The frequency is adjusted until it matches the resonance condition, where the energy of the microwave radiation corresponds to the energy difference between electron spin states.

 

Absorption of energy: When the resonance condition is met, the unpaired electrons can absorb energy from the microwave radiation and transition from one spin state to another. This absorption of energy is detected as a decrease in the intensity of the microwave radiation passing through the sample.

 

EPR spectrum: By varying the magnetic field strength, the absorption of energy is recorded as a function of the magnetic field. The resulting EPR spectrum shows distinct absorption peaks or lines, providing information about the magnetic properties of the sample, such as the number of unpaired electrons, their spin orientation, and their interaction with the surrounding environment.

 

Overall, EPR measures the response of unpaired electrons to external static magnetic fields and microwave radiation, allowing scientists to study the electronic structure and magnetic properties of materials. Therefore, EPR technology has a prominent role in many fields such as chemistry, biology, medicine, food and beverage, etc. CIQTEK's self-developed EPR spectrometer supports researchers in many application areas. Click to view the EPR application notes.