391results about How to "Solve the low detection efficiency" patented technology

An electromagnetic wave detector that detects incident light by converting the incident light into an electric signal includes a flat metal layer formed on a supporting substrate, an intermediate layer formed on the metal layer, a graphene layer formed on the intermediate layer, isolated metals periodically formed on the graphene layer, and electrodes arranged oppositely on both sides of the isolated metals. Depending on a size of a planar shape of each of the isolated metals, light having a predetermined wavelength at which surface plasmon occurs is determined out of the incident light, and the light having the predetermined wavelength is absorbed to detect a change in the electric signal generated in the graphene layer.

A system for selectively detecting charged particles produced due to operation of a charged particle beam column irradiating a specimen, including a proximal grid being selectively electrically biasable and configured for controllably directing the charged particles by electrically focusing the charged particles to compel selected secondary charged particles, whereupon being selected from the charged particles, to be attracted thereto, and to repel unselected secondary charged particles therefrom, a distal grid spaced apart from the proximal grid and separated therefrom by a gap and being selectively electrically biasable and configured for attracting the selected secondary and/or tertiary charged particles, whereupon being selected from the charged particles, to the distal grid, and to repel unselected tertiary charged particles therefrom, and a charged particle detector configured for detecting selected secondary charged particles attracted to the proximal and/or distal grid and detecting selected tertiary charged particles attracted to the distal grid, that impinge thereupon.

The invention discloses a crowd abnormity detection and positioning system and a crowd abnormity detection and positioning method based on a time recurrent neural network. The method comprises the steps of carrying out gridding division on a scene on the basis of preprocessing acquired sample data, and dividing a video fragment consisting of n frames into a plurality of time-space blocks; then constructing a multi-scale optical flow histogram and Gabor wavelet texture features in each time-space block; vectoring and combining the features in the multiple time-space blocks, finding out a relation between a space dimension and a time dimension by taking the video fragment as a time sequence through respectively using hidden nodes and feedback nodes of the time recurrent neural network, and training a time recurrent neural network model capable of detecting a long dependency relation; finally detecting and positioning a crowd abnormity by the model. The method is higher in instantaneity and accuracy, and can detect abnormities activated by a small quantity of individuals or a large quantity of individuals.

This invention relates to nondestructive control, more specifically, to the detection of cracks, flaws and other defects in oil and gas wells and cementing quality control.

The conventional detection technique has the following problems in detecting interference fringes: (1) Setting and adjustment are complex and difficult to conduct; (2) A phase image and an amplitude image cannot be displayed simultaneously; and (3) Detection efficiency of electron beams is low. The invention provides a scanning interference electron microscope which is improved in detection efficiency of electron beam interference fringes, and enables the user to observe electric and magnetic information easily in a micro domain of a specimen as a scan image of a high S/N ratio under optimum conditions.

The invention discloses a commercial oil surface laser code recognition method with a self-modeling function. The content of the method comprises the steps that model statistics is carried out on a commercial oil laser code based on a neural network recognition algorithm, and a self modeling technology is realized; a character template image of the designated commercial oil laser code to be detected is acquired, a brain cranial nerve function of the human is simply simulated through the neural network recognition algorithm so as to realize an input-output mapping model, classification, recognition and acquisition for characters are completed, and the characters act as a template; a commercial oil laser code image is acquired, and an image processing phase of character recognition and character reading is carried out; if a matching result is that the character is qualified, the commercial oil is qualified and continuous to be transported, and if the matching result is that the character is not qualified, the unqualified commercial oil is removed by a removing device; and finally, a function of character recognition is realized, character detection for a laser barcode on the commercial oil is completed, and thus accurate detection for the commercial oil laser barcode can be achieved.

An interactive combination of Phoswich detector array (PDA) and differential absorption lidar (DIAL) is proposed to trace the unknown radioactive plumes released into the atmosphere from a reactor stack, containment of the nuclear power plants, radioisotope separation laboratories, reprocessing plants or the uranium conversion facilities. The hybrid system represents a powerful technique for the prompt identification and quantification of the effluents with various radionuclide contents to determine the corresponding external dose rate accordingly.

An RF coil having at least three different resonance frequencies, wherein one of the resonance frequencies is adjusted to be a frequency f_A of a magnetic resonance signal generated by a test subject, and the coil is adjusted so that ratio of difference between the frequency f_A and a first frequency f_B lower than f_A and nearest to f_A among the resonance frequencies (f_A−f_B), and difference between the frequency f_A and a second resonance frequency f_C higher than f_A and nearest to the frequency f_A among the resonance frequencies(f_C−f_A), should be from 0.5 to 2.0. There is provided a technique for receiving magnetic resonance signals always with high detection efficiency by an RF coil of an MRI apparatus even if significant loss is caused in the RF coil, or test subject is changed.

The embodiments of the present invention disclose an event detection method and device. The method includes: predefining event-based detection rules with a predicative context-free grammar; generating by parsing the detection rules a parsing table of pushdown automaton which supports parallel parsing; receiving an event to be detected; and analyzing by a controller the event to be detected according to the parsing table, to obtain a detection result. The present invention is especially applicable to detection of network attack events. The embodiments of the present invention detect the attacks with a predicative context-free grammar on the basis of events, and ensure a close combination of a protocol parsing process and an attack detection process, as well as a close combination of multiple attack detection rules, thus decreasing unnecessary calculations. In addition, with an optimized parallel pushdown automaton, the embodiments of the present invention can efficiently analyze the predicative context-free grammar. Consequently, besides hierarchical processing capability and state description capability, the embodiments of the present invention deliver high efficiency.

The invention provides a microsatellite unstable site screening and analysis model construction method and device. The method comprises the following steps of: S1, taking a microsatellite site of a reference genome as a candidate MS site, S2, selecting a plurality of samples with known microsatellite instability detection state information as training set samples, carrying out mutation detection on candidate MS site areas of the training set samples, respectively recording mutation types and numbers, and calculating information entropy of mutation of each candidate MS site, and S3, correlatingthe microsatellite instability detection state information with the entropy of the information entropy of the mutation of each candidate MS site, selecting an entropy threshold of each candidate MS site for distinguishing the microsatellite instability detection result, and screening out the candidate MS site with a high distinguishing degree as an MSI site. According to the scheme, the problemsof low detection efficiency caused by excessive fixed MSI sites and low detection specificity and sensitivity caused by incapability of covering all types of samples in the prior art are solved.

The invention discloses a food-borne pathogenic bacterium detection system based on a high spectrum. The food-borne pathogenic bacterium detection system comprises a surface detection line, a sorting line, a qualified product conveying belt and a point detection line, which are connected with a control system respectively. The invention further discloses a detection method of the food-borne pathogenic bacterium detection system based on the high spectrum. The surface detection line based on a near-infrared high-spectrum system is used for rapidly positioning food-borne pathogenic bacteria; the sorting line is used for conveying pork polluted by the food-borne pathogenic bacteria to the point detection line; Raman chemical imaging is used for realizing species identification of the food-borne pathogenic bacteria. According to the food-borne pathogenic bacterium detection system disclosed by the invention, the problems that the resolution ratio of detecting a microorganism cell structure by the near-infrared high-spectrum system is limited and the large-area scanning and imaging efficiency of the Raman chemical imaging is low are solved; the food-borne pathogenic bacterium detection system based on the high spectrum has the advantages of convenience for utilization and obvious detection efficiency.

An ultrasonic sensor according to the present invention is used, for example, for detecting an obstacle positioned in front of an automotive vehicle. The ultrasonic sensor includes an piezoelectric element connected to an acoustic matching member and a processing circuit, all contained in a casing. Ultrasonic waves reflected on an object are received by the acoustic matching member and converted into electrical signals in the piezoelectric element. The electrical signals are processed in the processing circuit to thereby detect a distance to the object and/or positions of the object. A surface of the acoustic matching member connected to the piezoelectric element is made larger than the piezoelectric element to form an overhang area on a conductive layer formed on the acoustic matching member. In this manner, electrical connection in the ultrasonic sensor is easily made, and detection sensitivity of the ultrasonic sensor is enhanced.