Abstract: The present invention discloses a directionally modified glucosamine synthase mutant and its application. The amino acid sequence of the glucosamine synthase mutant is as shown in sequence list SEQ ID No. 1, and the nucleotide sequence is as shown in sequence list SEQ ID No. 2. The genetic engineering bacteria of glucosamine synthase is successfully constructed. In order to improve the tolerance of recombinant bacteria against glucosamine, the glucosamine synthase is directionally modified. A glucosamine synthase mutant is selected from the mutant library via high-throughput screening method, the amino acid changes in the mutant induces the spatial conformational change in the enzyme, so as enlarged the region where the enzyme and substrate combines, therefor the combination efficiency of the enzyme and the substrate is increased. The glucosamine synthase of the present invention has various advantages, such as rich in raw material of glucose, and a convenient subsequent extraction.

Abstract: The invention proposes a mass spectrometry apparatus for ultraviolet light ionization of neutral lost molecules, and a method for operating same. The mass spectrometry apparatus for ultraviolet light ionization of neutral lost molecules includes a quadrupole tandem special linear ion trap mass analyzer, a vacuum ultraviolet lamp, a lamp front shutter, a gradient vacuum system and other necessary components for the mass spectrometry apparatus. In addition, the invention also proposes a method for operating the apparatus to efficiently store ions, fragment and analyze the ions, perform ultraviolet efficient ionization on lost neutral molecules, and then analyze the ions.

Abstract: A mass spectrometry device and analysis method for a gas phase molecule-ion reaction. The device comprises a reaction gas introduction device and a gas phase molecule-ion reaction mass spectrometry analysis device, wherein the reaction gas introduction device is connected to the gas phase molecule-ion reaction mass spectrometry analysis device; the reaction gas introduction device is configured to introduce reaction gas into the gas phase molecule-ion reaction mass spectrometry analysis device; and the gas phase molecule-ion reaction mass spectrometry analysis device is configured to enable molecules or ions to be subjected to a reaction and carry out mass spectrometry analysis on a reaction result. The reaction gas introduction device comprises a reaction gas container, the reaction gas container being configured to contain gas or volatile liquid or solid and generate gas molecules needed by a reaction; and a reaction gas quantitation device, configured to carry out flow control on the gas molecules.

Abstract: The invention discloses a networking mass analysis method and device, and belongs to the field of mass spectrometer and ion mass analysis. The device comprises an ion source, an ion transporter, an ion deflector and multiple mass analyzers, wherein the ion transporter is connected with one of the multiple mass analyzers, the multiple mass analyzers are connected with the ion deflector respectively, the ion source produces the ions to be detected, the ions to be detected enter any of the mass analyzers connected with the ion deflector via the ion transporter for mass analysis, and the remaining ions to be detected are transported to the corresponding mass analyzers via the ion deflector for mass analysis. The invention can improve the mass analysis duty ratio of continuous ion sources and obtain more mass-to-charge ratio information of ion beams within each time slot.

Abstract: A method for analyzing ionic structure, including: applying a radio frequency electric field on an ion mass analyzer to cause sample ions to be excited to a motion amplitude, the motion amplitude at this moment being recorded as a primary motion amplitude; continuously feeding carrier gas into the ion mass analyzer and keeping a certain degree of vacuum in the ion mass analyzer, the sample ions being collided with the carrier gas and the motion amplitude being decreased gradually, and collecting a time domain signal of an image current generated by the sample ions during the process; and analyzing the time domain signal through a time-frequency analysis method and obtaining time-varying characteristic curves indicating corresponding relations between the motion frequencies of the ions having corresponding sizes and the collision cross sectional areas of the ions and the carrier gas, thus distinguishing among ions having different sizes.

Abstract: The present invention discloses a rectangular ion trap device and method for ion storage. The device comprises a front end cover including left electrode, middle layer insulator, and right electrode, wherein the left electrode and the right electrode are respectively positioned at both sides of the middle layer insulator; a rear end cover, wherein the rear end cover has the same axis as the front end cover, and the central position of the rear end cover electrode is penetrated; the front and rear electrodes and the upper and lower electrodes are symmetric along the axis of the front end cover, and these electrodes form a space region for ion storage about the axis between the front end cover and the rear end cover electrode. The present invention can increase the number of ions in storage within a unit time prominently.

Abstract: The present invention discloses a rectangular ion trap device and method for ion storage. The device comprises a front end cover including left electrode, middle layer insulator, and right electrode, wherein the left electrode and the right electrode are respectively positioned at both sides of the middle layer insulator; a rear end cover, wherein the rear end cover has the same axis as the front end cover, and the central position of the rear end cover electrode is penetrated; the front and rear electrodes and the upper and lower electrodes are symmetric along the axis of the front end cover, and these electrodes form a space region for ion storage about the axis between the front end cover and the rear end cover electrode. The present invention can increase the number of ions in storage within a unit time prominently.

Abstract: Provided is an ion source system for an atmospheric pressure interface, comprising an atmospheric pressure ion source (1), wherein the atmospheric pressure ion source (1) is connected downstream to a vacuum ion source (2). Also provided is a mass spectrometer, using the present ion source system as an ion source. The present ion source system uses a combination of the atmospheric pressure ion source (1) and the vacuum ion source (2), is suitable for test sample having variety of forms, and performs secondary ionization on a sample to be tested, thus enhancing ion transmission efficiency. The present mass spectrometer significantly increases ion transmission efficiency, thus enabling continuous injection of samples and testing, and increasing the scanning speed of the spectrometer, particularly suitable for miniaturized mass spectrometer.

Abstract: A method for analyzing ionic structure, including: applying a radio frequency electric field on an ion mass analyzer to cause sample ions to be excited to a motion amplitude, the motion amplitude at this moment being recorded as a primary motion amplitude; continuously feeding carrier gas into the ion mass analyzer and keeping a certain degree of vacuum in the ion mass analyzer, the sample ions being collided with the carrier gas and the motion amplitude being decreased gradually, and collecting a time domain signal of an image current generated by the sample ions during the process; and analyzing the time domain signal through a time-frequency analysis method and obtaining time-varying characteristic curves indicating corresponding relations between the motion frequencies of the ions having corresponding sizes and the collision cross sectional areas of the ions and the carrier gas, thus distinguishing among ions having different sizes.

Abstract: An ion trap-based device and method for analyzing and detecting bipolar ions is provided. The device includes multiple electrodes of an ion trap; a radio frequency voltage source configured to form a radio frequency electric field; a direct current voltage source configured to form a bias electric field, positive and negative ions in the ion trap being separated by the bias electric field; a first and second detectors, configured to detect the positive and negative ions, respectively. A bipole and quadrupole field direct current voltage detection modes may be employed. A single positive ion or negative ion operation mode in a conventional biological mass spectrometry method is improved, so that the positive and negative ion modes are performed simultaneously; without any resolution loss, the analysis speed is increased, the sample consumption is reduced, and the accuracy of quantitative analysis of the samples is improved.

Abstract: The disclosure provides a device and a method for analyzing an ion structure, comprising: pre-processing a time domain signal of a mirror current of ions to be measured that are obtained from an ion mass analyzer, to obtain a signal to be measured; extracting information about a position a spectral signal of the signal to be measured through a Fourier transforming: modulating the spectral peak signal, to obtain a modulated signal; filtering the modulated signal, to obtain a filtered signal; estimating parameters of an ion motion model with respect to the filtered signal, to determine information on structural characteristics of the ions to be measured from the estimated parameters. According to the device and the method for analyzing an ion structure of the present disclosure, the ion structures may be analyzed by directly analyzing the time domain signal of the mirror current of the ion.

Abstract: An ion trap-based device and method for analyzing and detecting bipolar ions is provided. The device includes multiple electrodes of an ion trap; a radio frequency voltage source configured to form a radio frequency electric field; a direct current voltage source configured to form a bias electric field, positive and negative ions in the ion trap being separated by the bias electric field; a first and second detectors, configured to detect the positive and negative ions, respectively. A bipole and quadrupole field direct current voltage detection modes may be employed. A single positive ion or negative ion operation mode in a conventional biological mass spectrometry method is improved, so that the positive and negative ion modes are performed simultaneously; without any resolution loss, the analysis speed is increased, the sample consumption is reduced, and the accuracy of quantitative analysis of the samples is improved.

Abstract: A multi-transformer LLC (resonant) power converter having at least two transformers including a first T1 and a second transformer T2 in series includes a switch network configured for receiving input power including a first and second switched node. Resonant circuitry is coupled between the first and second switched node including a series combination of an inductor, a capacitor, a primary winding of T1 and a primary winding of a T2. At least one switch is operable for providing a first mode that includes T2 in the resonant circuitry and a second mode that excludes T2 from the resonant circuitry. Secondary windings of T2 and T1 are connected electrically in parallel for driving an output capacitor (Co) through respective rectifiers which provide conversion from AC to DC.

Abstract: Methods, systems, and apparatus for accurately authenticating a document (e.g. a credit card) having a magnetic stripe are provided. The magnetic field at different points of the magnetic stripe are measured, e.g., by a checkout scanner to create a magnetic signature. Digital samples of the measurements may be used to create a representation of the magnetic signature. The representation can then be compared to reference values to produce a measure of the authenticity of the document. The reference values are updated over time to reflect changes in the magnetic stripe of the authentic document, as may occur due to physical deterioration. For example, reference values may be optimized based on recent measurements of the authenticated document to provide a more accurate determination of authenticity for future measurements.

Abstract: A signal quantizer includes a summing junction, a loop filter, a quantizer and a reconstruction filter. The summing junction is responsive to an input signal and to a modulated signal and is operative to combine the modulated signal and the input signal to generate a summing junction output. The loop filter is responsive to the summing junction output and is operative to generate a loop filter output and has a first regenerative gain associated therewith. The quantizer is responsive to the loop filter output and is operative to generate the modulated signal. The reconstruction filter is responsive to the modulated signal and is operative to generate a quantized output signal and has a second regenerative gain associated therewith that is substantially equal to that of the loop filter.

Abstract: A multi-transformer LLC (resonant) power converter having at least two transformers including a first T1 and a second transformer T2 in series includes a switch network configured for receiving input power including a first and second switched node. Resonant circuitry is coupled between the first and second switched node including a series combination of an inductor, a capacitor, a primary winding of T1 and a primary winding of a T2. At least one switch is operable for providing a first mode that includes T2 in the resonant circuitry and a second mode that excludes T2 from the resonant circuitry. Secondary windings of T2 and T1 are connected electrically in parallel for driving an output capacitor (Co) through respective rectifiers which provide conversion from AC to DC.

Abstract: An ion trap, a multiple-electrode-pole system and an electrode pole for mass spectrometric analysis. The electrode pole (1) is a rod and the shape of at least one side of its cross section is ladder-shape including two or more steps. It develops the structure of the electrode pole; so the mass spectrographs such as the multiple-electrode-pole system and the ion trap and so on using the electrode pole (1) have an optimized field shape and can be made easily with low cost.

Abstract: Methods, systems, and apparatus for verifying the identity of a cardholder are provided. A digital representation of a magnetic characteristic of a magnetic stripe of the card is stored on a portable electronic device of the cardholder. During a transaction, the digital signature is then transmitted so that it can be compared with a reference signature. The identity may be verified, and a response sent to a party requesting the verification, e.g., during a transaction between the requesting party and the verified party.

Abstract: Methods, systems, and apparatus for efficiently authenticating a document (e.g. a credit card) having a magnetic stripe are provided. The magnetic field at different points of the magnetic stripe are measured, e.g., by a checkout scanner to create a magnetic signature. Digital samples of the measurements may be transformed into coefficients of continuous basis functions, e.g., a Fourier transform. These coefficients are then compared to reference values (e.g. corresponding coefficients) to produce a measure of the authenticity of the document. The number of coefficients used can advantageously be smaller than the number of digital samples without compromising accuracy, thus using less bandwidth between a scanner and an authentication entity.

Abstract: A hydraulic jack comprising a hydraulically actuated saddle movable from a first lowered position to a second raised position, the jack having a handle which, when pumped up and down, hydraulically raises the saddle, lowering control means associated with the jack for preventing premature lowering of the saddle upon malfunction of the hydraulic actuation during raising of the saddle and a release lever engaging the lowering control means adapted to release the same and permit lowering of the saddle when the handle is pumped up and down.