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Aiming at the problem of accurately identifying the mechanical state of circuit breaker in the actual operation environment, a new fault diagnosis method of high voltage circuit breaker based on the combination of time-frequency multi-characteristics of acoustic signal was proposed. Firstly, the background noise database was established to remove the template noise. On this basis, the adaptive wavelet transform (AWT) was used to remove the residual noise. Then the kurtosis, crest factor and skewness indexes were extracted respectively to construct the time-domain characteristics. The acoustic signal was decomposed by variational mode decomposition (VMD) to obtain the IMF component. The power spectrum of the IMF was converted to the polar coordinates of the divided sub-region. The sensitivity of the main peak region was improved by the divergence factor, and the spectral difference entropy characteristics were calculated. The two jointly constructed the time-frequency multi-characteristics. Finally, kernel fuzzy c means (KFCM) clustering was used to pre-classify the characteristics, and then support vector machine (SVM) was used to establish training models to realize mechanical state identification. The diagnosis result shows that the accuracy of time-frequency multi-characteristics combined with KFCM-SVM diagnosis method is 98.75 %. It can reflect the status information of circuit breaker from multiple dimensions, and has high practical popularization value.

Using gadolinium nitrate, cobalt acetate, citric acid as main raw materials, GdCoO3 was successfully prepared by sol-gel method. The prepared samples were characterized by thermogravimetric differe...

Recently, flexible stretchable sensors have been gaining attention for their excellent adaptability for electronic skin applications. However, the preparation of stretchable strain sensors that achieve dual-mode sensing while still retaining ultra-low detection limit of strain, high sensitivity, and low cost is a pressing task. Herein, a high-performance dual-mode stretchable strain sensor (DMSSS) based on biomimetic scorpion foot slit microstructures and multi-walled carbon nanotubes (MWCNTs)/graphene (GR)/silicone rubber (SR)/Fe

There are two primary defects in the existing UAV avoidance systems: the system is memoryless; airborne radars are used to detect long-distance barriers, which are unreliable and expensive. The paper adopts the deep learning algorithm and ADS-B communication system based on a satellite base station to solve the above problems. It divides the avoidance problem into two parts: short-distance obstacle avoidance and long-distance route planning. On the one hand, the system establishes the knowledge base storing the previous avoidance experience and the matching mechanism, realizing the correspondence between input and experience through a deep learning algorithm. They can dramatically improve the reaction speed and safety of UAVs. On the other hand, the system realizes the interconnection between UAV and the satellite base station through the ADS-B communication system to replace the radars, putting the task of route planning on the satellite platform. Therefore, the satellite can achieve large-scale and all-weather detection to improve the overall safety of UAVs depending on its high and long-range characteristics. The paper also illustrates the design elements of the RF baseband integrated ADS-B transceiver and the simulation performance of the short-distance avoidance system in the end, whose results show that the system can be applied to dense obstacle environments and significantly improve the security of UAVs in a complex domain.

A pair of enantiomers {[Cu(L-pro)(L-tyr)]·2H2O}n (L-1) and {[Cu(D-pro)(D-tyr)]·2H2O}n (D-1) based on the chiral ligands L/D-proline and L/D-tyrosine were synthesized and investigated using single-crystal X-ray structure analysis, IR spectroscopy, thermogravimetric analysis, solid-state UV-Vis spectroscopy, circular dichroism, magnetic studies, and DFT calculations. The enantiomers L-1 and D-1 showed left and right-handed helicity, respectively. The magnetic studies indicated that they both showed weak ferromagnetic characteristics. In order to examine the chiroptical activities, we measured the solid-state CD and MCD spectra, which were both of opposite sign for the enantiomers. Compared to the CD spectra, the MCD signals for L-1 and D-1 are intensified at ∼500 nm and weakened at ∼700 nm, which is interesting and needs in-depth research. The further DFT calculations revealed that the magnetic field might directly influence the dyz orbital of the copper and π orbitals of the ligands to increase the electron density and intensify the CD absorption at about 500 nm, impact the dz2 orbital of the copper and π* orbitals of the ligands to decrease the electron density and lower the intensity of CD absorption at around 700 nm, which provides a new threshold for experimentalists and theoreticians to comprehend the magnetism and optics interaction in orbitals. The experimentally and theoretically investigated results are useful for deliberately boosting and weakening the circular dichroism signals in magnetically controlled technologies.

ZrCoCe getter films with thickness of ~ 2.3 μm were deposited on Si(100) wafers by direct current (DC) magnetron sputtering process. A 400-nm-thick Pd protection layer was then deposited on the as-deposited ZrCoCe film without exposure to atmosphere. Microstructure, surface morphology and surface chemical state of the films were analyzed. Moreover, hydrogen sorption properties were determined. The results show that the ZrCoCe film displays a cauliflower-like morphology and a porous columnar-like structure which is composed of nanocrystal grains. The Pd protection layer tightly adheres to the surface of the ZrCoCe film and efficiently prevents the oxidation of Zr under exposure to atmosphere. We find that the hydrogen sorption properties of the Pd-ZrCoCe film are significantly improved, in comparison with those of the as-deposited ZrCoCe film.

This study was performed to provide information on the frequencies of Rh antigens, alleles, and phenotypes from our region in Tianjin, China.This observational study was conducted on patients from January 2018 to March 2021 using a fully automated system for ABO and Rh typing of blood cells. The phenotypes of C, c, E, and e were detected by the slide method. The data were collected and calculations done to determine the antigen, phenotypes and allele frequencies.Four hundred thirty-three cases of Rh (D) negative phenotype were confirmed in 88,856 patients. Of the four Rh antigens (C, c, E, e) that were phenotyped by serological methods, the "e" antigen was found to have the highest frequency (99.74%). The most common Rh negative phenotype observed was ccdee, followed by Ccdee. The prevalence of Rh phenotypes ccdEe, CCdee, CcdEe, CCdEe, ccdEE were found to be rare in our population with percentages of 0.0473%, 0.018%, 0.018%, 0.0034%, and 0.0011%, respectively.Knowledge of red cell antigen phenotype frequencies in a population is helpful in terms of their ethnic distribution. We have determined the prevalence of Rh antigens and Rh phenotypes in China. The Rh blood group distribution in this population was different from that in other populations.

A nickel-catalyzed transformation of diazoacetates to α-carbonyl methylene radicals has been disclosed in the presence of hyperoxide using ethanol as a hydrogen source and solvent. This strategy is successfully applied in the formation of indolin-2-ones or 1,4-dicarbonyl compounds from acrylamides or enamides in moderate to good yields. These reactions undergo radical addition onto C-C double bonds followed by a cyclization/oxidation or an oxidation/hydrolysis process, respectively.

Based on the SMIC 0.13 um CMOS technology, this paper uses a 0.8 V supply voltage to design a low-voltage, ultra-low-power, high-gain, two-stage, fully differential operational amplifier. Through the simulation analysis, when the supply voltage is 0.8 V, the design circuit meets the ultra-low power consumption and also has the characteristic of high gain. The five-tube, fully differential, and common-source amplifier circuits provide the operational amplifier with high gain and large swing. Unlike the traditional common-mode feedback, this paper uses the output of the common-mode feedback as the bias voltage of the five-tube operational transconductance amplifier load, which reduces the design cost of the circuit; the structure involves self-cascoding composite MOS, which makes the common-mode feedback loop more sensitive. The frequency compensation circuit adopts Miller compensation technology with zero-pole separation, which increases the stability of the circuit. The input of the circuit uses the current mirror. A small reference current is chosen to reduce power consumption. A detailed performance simulation analysis of this operational amplifier circuit is carried out on the Cadence spectre platform. The open-loop gain of this operational amplifier is 74.1 dB, the phase margin is 61°, the output swing is 0.7 V, the common-mode rejection ratio is 109 dB, and the static power consumption is only 11.2 uW.

Background To study serologic and gene characteristics of the B(A) blood group of one patient in Tianjin, China. To investigate the blood transfusion for patients with B(A) blood group. Methods ABO subgroups were identified by standard serologic techniques in ABO typing discrepancy sample from one patient at the Tianjin Medical University General Hospital. DNA (deoxyribonucleic acid) was collected from his sample and PCR (polymerase chain reaction) was used to sequence exons 6 and 7. PCR products were sequenced to identify ABO subgroups and the B(A) allele. Molecular genotyping of the ABO gene was performed by DNA sequencing of exons 6 and 7 of the ABO gene. Results The patient's red cells showed mixed field agglutination reaction (MF) with anti-A and weak reaction (W+) with anti-H. However, it has strong agglutination reaction with anti-B. The patient's serum showed the presence of anti-A antibody, while it can't react with B cell. The serological characteristics of the patient's red cells were similar to AxB subtype. Variation sites were confirmed at 261delG, 297 A>G, 526 C>G, 640 A>G, 657 C>T, 703 G>A, 796 C>A, 803 G>C, 930 G>A in exon 6 and 7 of the ABO gene. The sequence was similar to B101 except for nt640 (A>G). Genotyping indicated that the specimen was B(A)04. Conclusions Molecular genotyping confirmed the ABO status as B(A)04. The B(A) blood group is associated with a complicated serologic phenotype and DNA detection is necessary for this atypical phenotype sample. To ensure the safety of transfusion, this study developed an emergency transfusion procedure for patients with B(A) type.

Low-power memories typically operate in the subthreshold region of the device; however, as the supply voltage continues to decrease, the impact of leakage current on SRAM stability becomes more significant. The traditional method of measuring static noise tolerance only considers the effect of voltage, and the measurement results are not accurate enough. Therefore, this paper proposes a leakage-current-based stability analysis that provides better metrics, reads current noise tolerance (RINM) and writes current noise tolerance (WINM) to measure the stability of subthreshold SRAMs. Both currents and voltages were taken into account. The results demonstrate that the method is more accurate than the conventional method under subthreshold levels.

To explored the progress of intensive care unit (ICU) delirium between 2010 and 2020 based on knowledge visualization analysis.The literatures related to ICU delirium included in Web of Sciences (WOS) and China National Knowledge Infrastructure (CNKI) databases from 2010 to 2020 were collected. A bibliometric analysis was performed. The growth trend was showed by Excel 2019 software. The information about country, institution and author were extracted by VOSviewer 1.6.15 for generating cooperative network, to find the main research power and each cooperative relation. At the same time, Citespace 5.0.R1 was used to analyze those high frequency keywords and bursting keywords and build the map of co-citation reference, in order to explore the evolution of research in the field of ICU delirium and the hotspots about this field in recent 10 years.A total of 1 102 Chinese journal articles and 2 422 English "Articles" or "Reviews" from 2010 to 2020 were collected preliminarily, and the number of published literatures increased steadily. In the respect of quality, the impact factors of most articles were concentrated between 2 and 3, and the literatures with impact factor over 5 accounted for 27.9% (337/1 209). According to the knowledge visualization analysis, the United States published most of the related articles (total 1 152) in this field, while the England and Canada ranked second and third respectively, totaling 220 and 204. In terms of the distribution of research institutions, the Vanderbilt University School of Medicine was not only far ahead in the number of publication (n = 149), but more importantly, top three high-impact authors located in this institution. The amount of domestic publications was lower than developed countries, however, the burst index, which reflected the sudden increase, ranked first (7.09), suggesting that the interest and investment of Chinese researchers was increasing recently. The most productive institution in China was Capital Medical University School of Nursing with totaling 23 articles. Wu Ying, who published most Chinese papers (n = 14), belongs to this institution. However, it was a pity that there was no large scientific community be constructed in China, and the cooperation between institutions was deficient. By generating the co-occuring keyword mapping, the research hotpots mainly focused on the prevention, treatment and prevention of delirium in mechanically ventilated patients, the effect of dexmedetomidine and exploring the risk factor of ICU delirium. Finally, the results of co-citation reference analysis showed that Cluster 4 (risk assessment) was still in the process of development, in hence it was the frontier in this domain.There was a big gap between China and leading countries in the field of ICU delirium research. The main research power was located in the United States, and the trending of future studies mainly focus on delirium-related risk assessment.

In this paper, we present a new digital baseband processor for UHF tags. It is a low-power and low-voltage digital circuit and adopts the Chinese military standard protocol GJB7377.1. The processor receives data or commands from the RF front-end and carries out various functions, such as receiving and writing data to memory, reading and sending memory data to the RF front-end and killing tags. The processor consists of thirteen main sub-modules: TPP decoding, clock management, random number generator, power management, memory controller, cyclic redundancy check, FM0 encoding, input data processing, output data processing, command detection module, initialization module, state machine module and controller. We use ModelSim for the TPP decoding simulation and communication simulation between tag and reader, and the simulation results meet the design requirements. The processor can be applied to UHF tags and has been taped out using a TSMC 0.18 um CMOS process.

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The joint spatial division and multiplexing (JSDM) technology was proposed for the FDD system obtains channel state information difficulty, which can reduces the downlink pilot training and CSIT uplink feedback cost effectively. As the primary part of JSDM, User grouping algorithms has a huge impact on system sum rate and system implementation complexity. Traditionally, such as K-means, K-medoids user grouping algorithms has the defects of selecting the initial grouping center randomly and the number of groups was preset. In this paper, a user grouping algorithm based on the density idea to obtain the number of groups and the initial grouping center was proposed, which divides the users in the cell into cores border and isolated users at first, core users can be connected by density to form a number of core user groups, then take the average of the core user groups as the initial grouping center, and finally, the border and isolated user was grouped by K-means algorithm. And, we proposed an low complexity user scheduling algorithm. The simulation result shows that the proposed algorithm is faster and better than the traditional user grouping algorithm, and the improved JSDM system sum rate based on the algorithm are further improved.

Correction for ‘How the magnetic field impacts the chiroptical activities of helical copper enantiomers’ by Jialu Wu et al., New J. Chem., 2021, DOI: 10.1039/D1NJ03803F.

The die model characterized with high design efficiency and strong correlation plays an important role in simulation and machining. Because of the complexity of structure and the changing shape of flow channel, current design tools lack in the level of automation so that design of an extrusion die is a nontrivial task. In this paper, an integral design method is proposed to improve the design efficiency and model correlation. The computer-aided design (CAD) system for plastic profile extrusion die is designed and implemented by integrating Visual Studio 2010 (VS2010) and Unigraphics NX (UG). The closed loop recognition algorithm (CLR), multi closed loops intelligent recognition (MCLR) algorithm, and multi closed loops matching (MCLM) algorithm based on feature recognition are proposed to realize automatic generation of ruled surface in flow channel. The integral design and automatic generation methods of die set are proposed to facilitate efficient formation of different structures and process holes. The particle swarm optimization (PSO) algorithm is put forward to obtain best position and specification for the interference parts. Three modules (integral sketches, integral flow channel, and integral die set) are developed, which focus on integrating the proposed automation design methods into their framework. A case application on die design is used to illustrate the proposed method. The results show that the developed CAD system not only improves the design efficiency of extrusion die but also enhances the design quality.

Ultrahigh-vacuum conditions for microelectromechanical systems (MEMS) packaging can be achieved and sustained using a nonevaporable getter (NEG) film technology. Better understanding of the processes involved in film deposition, activation, and poisoning could help optimization and engineering of the film properties. In the present work, highly porous ZrCoCe films were deposited on (100) silicon substrates by direct current magnetron sputtering. Film morphology and performance dependence on deposition pressure, substrate temperature and substrate outgassing were investigated. The studies reveal that the pressure of the Ar sputtering gas affects significantly the film structure. High working pressures produce open columnar structures, whereas low pressures produce dense layers. It is demonstrated that the variation of the substrate temperature results in a significant modification of the film morphology. The highest sorption speed obtained for substrate temperature of 150 °C, is clearly correlated with the high specific surface area and porosity of the ZrCoCe film. It has also been confirmed that sorption properties can be improved by substrate outgassing prior to deposition.

Substitution of K2O for Na2O content was performed for ferroelectric glass ceramics in the PbO-SrO-Na2O-Nb2O5-SiO2 system, in which a conventional melt quenching method was adopted for the parent glass production in order to investigate its effect on the crystallization process and associated dielectric properties. Phase identification combined with differential thermal analysis results show that the crystalline phase was compressed by the substitution of potassium ions. The hysteresis loop results demonstrate that by increasing the substitution of K+ for Na+, the maximal polarization was decreased while both the remanent polarization and coercive electric field increase. It is also noted that increasing the content of K+ could also reduce the dielectric constant of the glass ceramic system; the dielectric constant demonstrated a decrease from 775 to 299, meanwhile, the dielectric loss increased from 0.013 to 0.021 when 50 mol.% Na+ was replaced by K+. Additionally, leakage current results show that as more sodium ions are replaced by potassium ions, the leakage current increased and the resistivity decreased.