Search

To retrospectively analyze the clinical data of a patient with confocal laser endomicroscopy, and summarize nursing measures such as preoperative preparation, intraoperative coordination, postoperative care of adverse reaction care, psychological care and other targeted nursing interventions. It is required to carried comprehensive nursing interventions to reduce patient discomfort and ensure the success of confocal laser endomicroscopy. (本文总结1例行共聚焦激光显微内镜检查术患者的护理配合要点, 包括术前准备、术中配合以及术后常规护理、不良反应护理、心理护理等针对性护理措施, 以减轻患者不适症状, 保障患者共聚焦激光显微内镜检查的顺利完成。)

Due to complex environmental factors such as uneven illumination and high noise, unmanned electric locomotives in coal mines have low accuracy in multi object detection and difficulty in recognizing small objects. In order to solve the above problems, a multi object detection model for underground unmanned electric locomotives in coal mines based on SD-YOLOv5s-4L is proposed. On the basis of YOLOv5s, the following improvements are made to construct the SD-YOLOv5s-4L network model. The model introduces the SIoU loss function to solve the problem of mismatch between the direction of the real box and the predicted box, so that the model can better learn the position information of the object. The model introduces decoupled heads at the head of YOLOv5s to enhance the feature fusion and positioning accuracy of the network model. It enables the model to quickly capture multi-scale features of the object. The model introduces a small object detection layer to increase the original three scale detection layer to four scale. It enhances the model's feature extraction capability and detection precision for small objects. The experiment is conducted on a multi object detection dataset of the mine electric locomotives. The results show the following points. The mean average precision (mAP) of the SD-YOLOv5s-4L network model for various types of objects is 97.9%, and the average precision (AP) for small objects is 98.9%. Compared with the YOLOv5s network model, it improves by 5.2% and 9.8%, respectively. Compared with other network models such as YOLOv7 and YOLOv8, the SD-YOLOv5s-4L network model has the best comprehensive detection performance and can provide technical support for achieving unmanned driving of the mine electric locomotives.

Economic benefit is the basic starting point of all economic activities that further developing financial advantages is helpful for improve the market seriousness of companies. The development of enterprises lessens work utilisation and acquires greatest advantages with the base speculation. Therefore, in this paper, the evaluation indices of economic benefit in enterprises are classified and the analysis model of economic benefit based on K-means clustering is established. According to the principal component analysis method, multi-dimensional analysis is conducted on X Company’s orders, income and expenditure data, loan amount and other aspects, which can help the senior leaders to scientifically manage and control the economic situation of the company, and make a better scientific forecast for future development.

The flush air data sensing system is a key or important flight sensor subsystem for the measurement of flight atmospheric parameters such as air pressure altitude, indicated airspeed, Mach number, angle of attack and sideshow angle, which are required for flight safety control, communication and navigation of flying wing pneumatic layout aircraft and precise weapon strike. The effectiveness of water-proof, dust-proof, anti-ice and de-icing design of the flush air data pressure sensor in the system is an important guarantee for accurate pressure feeling, stability of atmospheric parameters and real-time performance during flight. In this paper, aiming at the technology present status of water-proof, dust-proof, anti-icing and de-icing of flush air data pressure sensors in flush air data system, the existing shortcomings and defects are analyzed, combined with the needs of engineering application and research results of related engineering technology, the flush air data pressure sensor for complex meteorological environment protection status online monitoring, heater power adaptive control and rapid disassembling design as development direction is proposed, the future research goal and content of flush air data pressure sensor for complex meteorological environment protection technology are illustrated, and the solutions of key technologies such as moisture monitoring technology, freezing condition monitoring technology, surface hydrophobic and low detectable technology and easy maintenance structure design technology are presented.

Extractive electrospray ionization (EESI) technology has the advantages of directly ionizing the target molecules in the samples without complex sample pretreatments, and it is widely used for analysis of complex matrix samples, especially for aerosol samples. However, the current EESI device with open structure is easily affected by the surrounding environmental factors, especially susceptible to the airflow disturbance and exogenous aerosols. To solve this problem, an enclosed-structure EESI device was developed in this work. Three standard solutions of histidine, reserpine and MRFA were used to test the performances of the enclosed and open EESI-MS under laboratory conditions, respectively. The results showed that intra-day precision and sensitivity of enclosed EESI device are slightly better than that of open EESI device. Then, the performances of the two EESI-MS devices were tested with reserpine solution under different external air flow rates. As the external air flow rate increased, the intra-day precision of the open EESI device gradually decreased (RSD increased from 3.4% to 5.6%), and the intra-day precision of the enclosed EESI device remained good (RSD increased from 2.4% to 3.6%), indicating that the enclosed EESI device has a strong ability to resist airflow disturbance. The glucose aerosols of different concentrations were used to test the enclosed EESI-MS for 5 consecutive days. The results showed that intra-day precision (RSD

The effects of low-frequency electromagnetic casting (LFEC) on the microstructure and tensile properties of 5A90 Al–Mg–Li alloy with and without minor Sc were investigated. In addition to minor Sc, the refined microstructures of the conventional direct chill cast (DCC) alloy and the microstructures of the as-cast alloy were refined further and more equiaxed grains formed in LFEC ingots with Sc. Higher density, smaller size, and more uniform distribution Al3(Sc, Zr) in the aged alloy with Sc induced by LFEC, which pins on grain boundaries, can effectively inhibit recrystallization. As a result, it had been a significant improvement in strength which was mainly due to the Orowan effect of Al3(Sc, Zr) dispersoids combined with grain refinement. The ultimate tensile strength of 565.4 MPa, yield strength of 475.3 MPa, and the corresponding elongation of 6.4% were obtained in the as-aged 5A90 alloy with 0.15 wt% Sc cast by LFEC at 10 Hz and 100 A.

The peripherally inserted central catheter has been widely used in clinical setting because of its advantages of easy-to-use, safe and long‐term indwelling. Doctors and nurses should pay more attention on PICC-related complications during treatment. This paper summarized the common PICC-related complications and it influencing factors and nursing countermeasures, and provided reference for quality improvement of PICC maintenance. (经外周中心静脉置管(PICC)具有操作简单、安全可靠、留置时间长等优势, 在临床应用广泛。PICC相关并发症的防治是医护人员关注的重点。本研究总结了常见的PICC相关并发症, 并对相关影响因素和护理对策进行了归纳, 旨在为进一步提高PICC使用质量提供参考。)

Department of Emergency Medicine is an important division providing medical care to critically ill patients. Transport of critically ill patients is often required from the intensive care unit (ICU) to other hospital departments for imaging or medical procedures. Changes in treatment environment, insufficient medical resources during transport may lead to adverse events. There is an urgent need to reduce the risk of adverse events during transport. This paper summarized reviews studies on adverse events in perspectives of current situation, risk factors and nursing countermeasures, and provided reference for quality improvement of intrahospital transport of critically ill patients. (急诊科是急危重症患者诊疗的重要平台。在急诊科护理工作中, 危重症患者常因检查或治疗的需要进行院内转运, 转运过程虽短, 但由于治疗环境的改变, 转运过程中治疗、护理资源的缺乏, 可能导致不良事件的发生。如何有效减少急诊危重症患者院内转运过程不良事件发生是临床急需解决的难题。本文对急诊危重症患者院内转运过程中不良事件的发生情况、风险因素分析以及护理干预策略进行综述, 旨在提高急诊危重症患者院内转运质量。)

7T ultra⁃high field MRI (7T MRI), with its high resolution, high signal⁃to⁃noise ratio (SNR) and high contrast, is superior to conventional field intensity MRI in clinical applications such as diagnosis of hippocampal sclerosis (HS) and focal cortical dysplasia (FCD), assisting in the identification of pathological subtypes of the both, locating the scope of surgical excision, and has made progress in the diagnosis and treatment of drug⁃resistant epilepsy (DRE). This paper aims to review the clinical application value and research progress of 7T MRI in order to promote its application in the field of diagnosis and treatment of epilepsy.

Objective To compare the efficacy of dual-frequency dual-pulse laser lithotripsy under endoscopic retrograde cholangiopancreatography (ERCP) and traditional endoscopic mechanical lithotripsy in the treatment of patients with common bile duct stones, and summarize perioperative nursing measures. Methods From May 2018 to May 2022, the clinical data of 200 patients with common bile duct stones who underwent ERCP treatment and lithotripsy were retrospectively analyzed, of which 69 patients were treated with dual-frequency dual-pulse laser lithotripsy (Laser group) and 131 patients were treated with mechanical lithotripsy (Mechanical group), and the success rate of stone extraction, operation time, postoperative hospital stay time and complications of two groups of patients were compared. Results There was no significant difference in baseline data such as general conditions and preoperative clinical data between two groups (P＞0. 05). Neither neither Laser group nor Mechanical group had reported the perioperative death case. There were no significant difference in postoperative bleeding, postoperative pancreatitis and perforation complication rates in the two groups (P＞0. 05). The surgical time in the Laser group was significantly longer than that in the Mechanical group (P＜0. 05). The postoperative hospital stay was shorter in the Laser group than that in the Mechanical group(P＜0. 05), and the total complication rate and stone residue rate were lower in the Laser group than those in the Mechanical group (P＜0. 05). Conclusion The treatment of common bile duct stones by dual-frequency dual-pulse laser lithotripsy has better efficacy and lower complication rate than traditional surgical mechanical lithotripsy, but there is still room for improvement in the operation time. (目的 比较内镜逆行胰胆管造影术(ERCP)下双频双脉冲激光碎石与内镜下传统机械碎石治疗胆总管结石患者的效果, 总结护理经验。方法 回顾性分析2018年5月—2022年5月在北京中医药大学东方医院消化内镜中心行ERCP治疗并碎石的200例胆总管结石患者的临床资料, 其中69例患者采用双频双脉冲激光碎石术(激光组), 131例患者采用机械碎石(机械组)。比较两组患者的取石成功率、手术时间、术后住院时间、并发症等情况。结果 两组患者一般情况、术前临床资料等基线资料比较, 差异无统计学意义(P＞0. 05)。激光组和机械组均无围术期死亡患者。两组患者术后出血、术后胰腺炎、穿孔并发症率比较差异无统计学意义(P＞0. 05)。与机械组相比, 激光组的手术时间较长(P＜0. 05), 术后住院时间更短(P＜0. 05), 总并发症率和结石残留率更低(P＜0. 05)。结论 ERCP下双频双脉冲激光碎石治疗胆总管结石具有比传统手术机械碎石更好的效果及更低的并发症率, 但手术时间仍有改进的空间。)

The article defines the problem of training specialists who manage water resources logistics. The problems of water logistics are related to peculiarities of transportation of water resources in order to preserve their quality characteristics, operation of hydraulic structures, preservation of coastal territories and their corresponding ecosystems. Effective implementation of the processes related to the above features requires constant analysis of a multitude of parameters and processes, which in most cases are random in nature. The development of operational management solutions requires the use of specialized intelligent software tools. Their effective use requires professional training. The study developed a model of the educational process that uses technologies of digital twins of real natural objects, which allowed forming professional competencies in the field of water resources logistics in an interactive form.

The High Energy Photon Source (HEPS) is expected to produce a substantial volume of data, lead to immense data I/O pressure during computing. Inefficient data I/O can significantly impact computing performance. To address this challenge, firstly, we have developed a data I/O framework for HEPS. This framework consists of three layers: data channel layer, distributed memory management layer, and I/O interface layer. It mask the underlying data differences in formats and sources, while implementing efficient I/O methods. Additionally, it supports both stream computing and batch computing. Secondly, we have designed a data processing pipeline scheme aimed at reducing I/O latency and optimizing I/O bandwidth utilization during the processing of high-throughput data. This involves breaking down the computing task into several stages, including data loading, data pre-processing, data processing, and data writing, which are executed asynchronously and in parallel. Finally, we introduce the design of stream data I/O process. The primary objective of stream data I/O is to enable real-time online processing of raw data, avoiding I/O bottlenecks caused by disk storage. This approach ensures the stability of data transmission and integrates distributed memory management to guarantee data integrity in memory.

A novel concept is described here that utilizes externally applied heat to a solid rod of reconstituted tobacco biomass to form a stream of aerosol under progressively oxygen-deficient atmosphere. The boundary of auto-ignition was determined at oxygen concentrations of 0%, 5%, 10%, and 21% and then the effects of these different atmospheres on various parameters were studied. Experimental results indicated that the ignition temperature decreased with the increase of oxygen concentration and a negative temperature coefficient (NTC) for atmosphere with oxygen was observed at before but close to ignition temperature. Significant differences in the yields of CO and CO2 between oxygen and oxygen-free atmosphere were observed. The mass of aerosol produced under an inert atmosphere and reduced-oxygen atmosphere were characterized with selected volatile and semi-volatile components, phenols, aldehydes, and other organic compounds of interests. In addition, higher oxygen concentration resulted in higher bulk and surface oxygen content of solid-phase residue, the reduction of carbon and hydrogen element content and related functional groups, and the content of inorganic compounds also exhibited an increase with oxygen concentration. By systematically changing oxygen concentrations of the biomass bed with increasing temperatures, an aerosol stream of controlled chemical composition and yields could be formed without leading to ignition. Key chemical markers of inhalation harm were measured and compared to each other under different degrees close to combustion. Studying reconstituted tobacco or other biomass materials in such a way could provide alternative and useful information in the design heated biomass aerosol generators.

A lit cigarette forms a positive and negative pressure zone by a puff with respect to the position of its paper burn line. Smoke aerosols generated from the two zones are then pulled through the rod under the puff to form the mainstream smoke. This phenomenon is fundamental to the thermophysics and the resultant chemical composition of the mainstream smoke. In this study, we created two different airflow pathways inside a heated tobacco rod by a puff, and investigated the differences in aerosol formation and its chemical compositions. The two different pressure-induced conditions, one through an open-ended tobacco rod (marked as HNB, a label of a designed airflow pathway of commercial heated tobacco products called heat-not-burn prior), and the other through a closed-ended tobacco rod (marked as NSC, a label of a novel-designed airflow pathway of heated tobacco products), were compared for their aerosol collected mass (ACM), the contents of nicotine, water and added aerosol agents such as propylene glycol (PG) and glycerol (VG), as well as selected aldehydes and ketones in the mainstream aerosol. Aerosol particle distribution and the heated temperature along different rod locations were also compared during a puff. The results indicated marked differences in the aerosol formation processes between the two HNB and NSC systems. The transfer ratios of the main aerosol components were significantly higher for the NSC; the levels of formaldehyde and acetaldehyde were significantly lower under the NSC than the HNB condition. There were also significant differences for the aerosol particle number concentration (APNC) and count median diameter (CMD) for the two systems. The lack of convective heat transfer in the aerosol formation under the NSC condition resulted in a relatively stable thermal aerosol generation zone, reflected by the temperature difference between the two systems in the selected locations. The NSC mode of tobacco heating thus offers a novel and enhanced aerosol generation for heat tobacco product designs.

This paper summarizes the nursing experience of a patient who received endoscopic variceal ligation in the treatment of esophageal varices, including preoperative psychological care, instrument preparation, patient preparation, intraoperative care, postoperative general care, complication care and other targeted nursing measures. Through the comprehensive nursing mode, full preoperative preparation, close surgical cooperation, and meticulous postoperative care, the success of esophageal variceal ligation was guaranteed, the pain of patients was reduced, the patient's symptoms were improved. (本文总结1例内镜下食管静脉曲张套扎术治疗食管静脉曲张患者的护理体会, 包括术前的心理护理、器械准备、患者准备、术中护理、术后一般护理、并发症护理等针对性护理措施。充分的术前准备、密切的手术配合和细致的术后护理是保障食管静脉曲张套扎术成功的关键, 有助于减轻患者疼痛, 改善患者病症, 促进其康复。)

In the present study, a comparative genome analysis of the novel alkaliphilic actinobacterial Nesterenkonia haasae with other members of the genus Nesterenkonia was performed. The genome size of Nesterenkonia members ranged from 2,188,008 to 3,676,111 bp. N. haasae and Nesterenkonia members of the present study encode the essential glycolysis and pentose phosphate pathway genes. In addition, some Nesterenkonia members encode the crucial genes for Entner-Doudoroff pathways. Some Nesterenkonia members possess the genes responsible for sulfate/thiosulfate transport system permease protein/ ATP-binding protein and conversion of sulfate to sulfite. Nesterenkonia members also encode the genes for assimilatory nitrate reduction, nitrite reductase, and the urea cycle. All Nesterenkonia members have the genes to overcome environmental stress and produce secondary metabolites. The present study helps to understand N. haasae and Nesterenkonia members’ environmental adaptation and niches specificity based on their specific metabolic properties. Further, based on genome analysis, we propose reclassifying Nesterenkonia jeotgali as a later heterotypic synonym of Nesterenkonia sandarakina.

Objectives: The role of community in individuals' well-being has been extensively examined in the Western context. However, little is known about how the host community is related to sojourners' well-being in a crisis in an Asian context. The current study aims at exploring international students’ sense of community in the Chinese context under the direct threat of a global health crisis. Methods: Using a cross-sectional sample of 102 international students staying in Wuhan during the 76-day lockdown at the earliest stage of the COVID-19 pandemic, the current study explored the relationship between international students’ sense of community and anxiety, and the mediating role of social contact, social support from three key sources in the host community (host university, international students, and Chinese friends). Results: Results showed that participants’ stronger sense of community indirectly reduced anxiety via the role of sources of contact and support from the host community. Conclusions: This study provided further evidence to support the nurturance of the sense of community in community resilience and provided implications on how the host community can help to enhance sojourners’ psychological well-being in a global crisis.

At present, there are some problems in the identification of stones and other small obstacles in the track during the driving of unmanned underground electric locomotive in coal mines, such as slow detection speed, low detection precision, and easy to cause missing detection and wrong detection for overlapping objects. In order to solve the above problems, a multi-target detection model (SE-HDC-Mask R-CNN) for underground electric locomotive is proposed. The model is improved on the basis of Mask R-CNN. By embedding a squeeze-and-excitation (SE) module in the residual block of the backbone feature extraction network ResNet, the importance and interrelation of each channel are learned. The capability of feature selection and capture of the network is enhanced. The standard convolution with a kernel size of 3×3 in the residual block is replaced with hybrid dilated convolution (HDC). On the premise of not changing the size of the feature image and not increasing the amount of parameter calculation, the receptive field can be increased by increasing the distance between the values when the convolution kernel processes the data. The experimental result show that the SE-HDC-Mask R-CNN model can effectively extract track, electric locomotive, signal light, pedestrian and stone objects. The average precision rate on the multi scene operation data set of underground electric locomotive is 95.4%, the average mask segmentation precision is 88.1%, the average bound box intersection ratio is 91.7%, the three indicators are all improved by 0.5% compared with the Mask R-CNN model. The detection precision of signal light and stone (small objects) is improved by 0.7% and 4.1% respectively. The comprehensive performance of SE-HDC-Mask R-CNN model is better than that of YOLOV2, YOLOV3-Tiny, SSD and Faster R-CNN model. The SE-HDC-Mask R-CNN model can effectively solve the problem of missing detection of small objects. The SE-HDC-Mask R-CNN model can effectively realize object detection in coal roadway straight track, curved track, dark environment, multi-object overlapping and other scenarios. It has certain generalization capability and high robustness, and basically meets the requirements of unmanned electric locomotive obstacle detection.

The early diagnosis of myocardial infarction can significantly improve the survival rate in emergency treatment, which is mainly implemented by the immunoassay for myocardial infarction biomarkers such as cardiac troponins in blood. In this work, a disposable optofluidic microtubule whispering gallery mode (WGM) immunosensor for label-free cardiac troponin I-C (cTnI-C) complex detection has been proposed and demonstrated with active interrogation enhancement. The disposable microtubule is simply fabricated by a silica capillary with pressurized tapering technology for thin-wall, and the cTnI antibodies are immobilized on the inner wall surface of the microtubule through the self-adherent polydopamine substrate. By configuring the two coupling microfibers, the double-fiber-coupled microtubule cavity can serve as a tunable filter for the mutual-coupled polarimetric fiber ring laser (FRL), whose output laser wavelength is determined by the cTnI-C concentration in the optofluidic microtubule with inherent microfluidic channel. Due to the cyclic-cumulative gain of the FRL, the characteristic resonant peak of optical sensing signal is enhanced in the spectral width compression and the optical signal-to-noise ratio improvement, and therefore the optical immunosensor for cTnI-C can be achieved by tracking the output laser wavelength of the FRL conveniently. The dynamic binding and unbinding process of cTnI-C antigen–antibody is illustrated by monitoring the lasing peak wavelength continuously. Our all-fiber immunosensor demonstrated here has the advantages of fast label-free detection, real-time monitor, high sensitivity and disposable sensing element, which can be an innovative detecting tool in early diagnosis of myocardial infarction.

In order to provide the basis of the selection of service casing material in a representative oil field in the middle east. The effects of different CO2 partial pressure, H2S partial pressure, water content, immersion time and other factors on the corrosion behavior of L80 - 1 casing material in a representative oilfield in the Middle East was studied by weight loss test, orthogonal test, SEM and XRD. Results showed that water content was the most important factor affecting the corrosion rate of L80 - 1 steel, followed by CO2 partial pressure, H2S partial pressure and temperature, and Cl- concentration was the least. With the prolonging of the immersion time, the corrosion rate of L80 - 1 steel decreased, and the film became more and more compact and flat. With the increase of CO2 partial pressure, the corrosion rate of L80 - 1 steel showed a trend of increase first and then decreased, reaching the maximum value at 2.00 MPa. With the increase of H2S partial pressure, the corrosion rate of L80 - 1 steel increased continuously. The corrosion of L80 - 1 steel was slight in the early stage of exploitation, but once the water content in the produced liquid exceeded 30%, the corrosion rate increased rapidly, so anti - corrosion measures must be taken in the middle and late stages of exploitation. Based on the basic data of corrosion behavior research, CO2 - H2S corrosion charts of several casing steels were drawn. The corrosion charts showed that the application scope of L80 - 1 steel was limited in typical Middle East oil field corrosion environment, and L80 - 3Cr steel might be a better choice for the long - term safe exploitation of oil field as it could balance the requirements regarding corrosion resistance and cost saving.

In recent years, with the rapid development of electric power informatization, smart meters are gradually developing towards intelligent IOT. Smart meters can not only measure user status, but also interconnect and communicate with cell phones, smart homes and other cloud devices, and these core functions are completed by the smart meter embedded operating system. Due to the dynamic heterogeneity of the user program side and the system processing side of the embedded system, resource allocation and task scheduling is a challenging problem for embedded operating systems of smart meters. Smart meters need to achieve fast response and shortest completion time for user program side requests, and also need to take into account the load balancing of each processing node to ensure the reliability of smart meter embedded systems. In this paper, based on the advanced Grey Wolf Optimizer, we study the scheduling principle of the service program nodes in the smart meter operating system, and analyze the problems of the traditional scheduling algorithm to find the optimal solution. Compared with traditional algorithms and classical swarm intelligence algorithms, the algorithm proposed in this paper avoids the dilemma of local optimization, can quickly allocate operating system tasks, effectively shorten the time consumption of task scheduling, ensure the real-time performance of multi task scheduling, and achieve the system tuning balance. Finally, the effectiveness of the algorithm is verified by simulation experiments.

We investigate the multiplicity of subharmonic solutions for indefinite planar Hamiltonian systems J⁢z′=∇⁡H⁢(t,z){Jz^{\prime}=\nabla H(t,z)} from a rotation number viewpoint. The class considered is such that the behaviour of its solutions near zero and infinity can be compared two suitable positively homogeneous systems. Our approach can be used to deal with the problems in absence of the sign assumption on ∂⁡H∂⁡x⁢(t,x,y){\frac{\partial H}{\partial x}(t,x,y)}, uniqueness and global continuability for the solutions of the associated Cauchy problems. These systems may also be resonant. By the use of an approach of rotation number, the phase-plane analysis of the spiral properties of large solutions and a recent version of Poincaré–Birkhoff theorem for Hamiltonian systems, we are able to extend previous multiplicity results of subharmonic solutions for asymptotically semilinear systems to indefinite planar Hamiltonian systems.

BACKGROUND In recent years, more attention has been paid to the protection of the environment in China. More damaged or polluted land needs to be reclaimed. When evaluating the effect, it is necessary to detect several pollutant indexes for phenolic pollutants. In the direct determination of phenolic compounds by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS), there are challenges such as low chromatographic response, poor stability and high detection limit. OBJECTIVES To establish a method to determine 19 phenolic pollutants in reclaimed land. METHODS Based on the characteristics of complex matrix, multiple interference factors, and difficult pre-processing of reclaimed land samples, the extraction and purification methods of this type of sample were screened and optimized. The extraction and purification methods were determined by comparing the effects of derivatization and non-derivatization, combined with comprehensive research on the optimization of derivatization conditions and the measurement results of actual samples. A derivatized gas chromatography-mass spectrometry method for detecting 19 phenolic pollutants in reclaimed land samples was established (Among them, 2, 4, 6-trichlorophenol and 2, 4, 5-trichlorophenol, 2, 3, 4, 5-tetrachlorophenol and 2, 3, 5, 6-tetrachlorophenol were combined because of could not be separated). The samples were extracted with n-hexane and acetone (1:1, V/V) by ASE. The extract was concentrated, purified and derivatized by pentafluorobenzyl bromide. Finally, it was determined by GC-MS internal standard method. RESULTS The standard-addition recoveries were 73.3%-107.0%. The method detection limits of phenolic compounds in soil were 0.67-3.95μg/kg, which was significantly lower than nonderivative method (10-80μg/kg). The derivatives had better stability and higher chromatographic response, the groups were more even in peak height (area) on the chromatogram. The derivatization method had better reproducibility and the results of low-concentration samples were more accurate. CONCLUSIONS This method can be used effectively to avoid matrix interference and provide reference for trace determination of phenolic pollutants in soil samples with complex matrix.

SARS-CoV-2 has spread worldwide and poses a great threat to human health. Among COVID-19 patients, those with hypertension have been reported to have higher morbidity and mortality. This study was conducted to provide the international community with a deeper understanding of COVID-19 with hypertension.

Carbide slag has been used to prepare solidified soil to effectively reduce the stacking and disposal of carbide slag and achieve efficient resource utilization. Because of the significant brittleness and low strength of carbide-slag-stabilized soil, fibers were added to carbide-slag-stabilized soil in this experimental study. The effects of fiber length and fiber content on the unconfined compressive and indirect tensile strengths of carbide-slag-stabilized soil were investigated. The concepts of the density of fibers in solidified soil and the number of fibers in a unit volume solidified soil were proposed, and the effects of fiber distribution density on the mechanical properties of the solidified soil were evaluated. The fibers increased the indirect tensile strength of the carbide-slag-solidified soil, which was significantly higher than the unconfined compressive strength of the solidified soil. The fibers had no significant effect on the unconfined compressive and indirect tensile strengths of the 7 d carbide-slag-solidified soil but increased those of the 28 d carbide-slag-solidified soil. The enhancement effect was the most significant when a 0.3% content of 19 mm long fibers was incorporated into the carbide-slag-solidified soil.

BACKGROUND Isotope geochronology is a basic subject to explore the temporal and special evolution of geological bodies and geodynamics. The U-Pb dating technology of accessory minerals is the most widely used in isotope geochronology. Titanite has a relatively low closed temperature for U-Pb isotopic system and is common in magmatic rocks, metamorphic rocks, hydrothermal-related rocks and a few sedimentary rocks. This indicates that it is an ideal mineral for U-Pb dating to constrain the medium to high temperature geological event. OBJECTIVES To understand the element fractionation behavior during laser ablation-inductively coupled plasms-mass spectrometry (LA-ICP-MS) U-Pb dating and propose corresponding correction methods. METHODS In situ U-Pb dating were performed using a Geolas Pro laser-ablation system and a 7700x quadrupole ICP-MS. A stationary laser ablation spot with a beam diameter of 24μm was used for the analyses. The ablated aerosol was carried by helium and then combined with argon via a T-connector before being introduced to the ICP-MS plasma. After smoothed, the sample gas will go into quadrupole ICP-MS for U-Pb dating. Each analysis incorporated a background acquisition of approximately 10s (gas blank) followed by 40s data acquisition from the sample. After the experiments, the fractionation behavior of elements of titanite during the laser ablation were compared for using different fractionation correction methods to correct zircon, monazite and titanite separately. These correction methods were based on different mathematical model such as quadratic curve, power function and so on. The data was processed with different softwares such as GLITTER and BUSTER based on different mathematical equations, in order to look for the appropriate correction methods for different uranium-rich minerals based on different fractionation characteristics. RESULTS The inconsistent fractionation behavior of elements between different titanite particles was revealed. After comparison, it was proposed that the 'Exponential Function Method' and the 'Average Data method' can only be used for uranium-rich minerals minerals that have consistent fractionation behavior, but it was not pragmatic for inconsistent ones. For these uranium-rich minerals minerals such as tianite, the 'Intercept Method' was an improvement on the current method, in order to ascertain the correct age. CONCLUSIONS It is indicated that the 'Intercept Method' can avoid inaccurate correction caused by inconsistent fractionation behavior.

Jatropha curcas biodiesel was taken as the research object, studied the single and compound effects of oxidation degree and temperature on kinematic viscosity of biodiesel, and established a mathematical model. The results indicate that the kinematic viscosity of biodiesel decreases gradually with the increase of temperature, and the mathematical model affected by the single factor of temperature is η = e(A + Bt + Ct2) . The kinematic viscosity of biodiesel increases with the increase of oxidation time. The regression equation between kinematic viscosity and conductivity is established as follows: η = A + Bμ. It is found that the influence of temperature on the kinematic viscosity of biodiesel is much greater than that of oxidation, and the higher the temperature, the lower the influence of oxidation on the kinematic viscosity of biodiesel. Through the analysis of the influence weight of two factors and the change rate of kinematic viscosity, it is found that with the increase of temperature, the effect of conductivity on the change rate of kinematic viscosity of biodiesel is positive, but the influence decreases gradually. The relationship between kinematic viscosity, temperature and oxidation

In view of multi-objective optimization problem in structure design of mine crawler robot with two rocker arms, a structure optimization design scheme of mine crawler robot with two rocker arms based on GA-PSO algorithm was proposed. Influence factors of maximum obstacle crossing height of robot and centroid position change are obtained through geometry and kinematics analysis of obstacle crossing process of the robot. According to work requirements of mine robot, constraint conditions are established to get multi-objective optimization function, and the multi-objective optimization problem is transformed into a single-objective optimization problem by introducing weight coefficient. GA-PSO algorithm is used to solve the single-objective optimization problem, and the optimal structural parameters of the robot are obtained: the quality of the car body is 10 kg, the quality of the rocker arm is 5 kg, the distance between front and rear wheels is 600 mm, the radius of drive wheel is 115 mm. The simulation results show that the energy consumption of the robot adopting above parameters is lower than other design schemes, and the target motion is easier to achieve.

In this paper, a novel semi-supervised classification method based on the Neighborhood Minimum Spanning Tree (NMST) is proposed to solve the Polarimetric Synthetic Aperture Radar (PolSAR) terrain classification when labeled samples are few. Combining the idea of self-training method and spatial information of the pixels in PolSAR image, a new help-training sample selection strategy based on spatial neighborhood information is proposed, named as NMST, to select the high reliable unlabeled samples to enlarge the training set and improve the base classifier. Finally, the PolSAR image is classified by this improved classifier. The experiments results tested on three PolSAR data sets show that the proposed method achieves a better performance than existing classification methods when the number of labeled samples is few.

Gegen Qinlian Decoction (GQD) is a commonly used traditional Chinese medicine formula for treating type 2 diabetes mellitus and insulin resistance (IR). The effects of GQD treatment on intestinal flora and its metabolism, however, are yet to be understood. In this study, the effects of GQD treatment on the fecal metabonome of high fructose-induced IR rats were investigated with a 1H NMR-based approach. The IR model was established by feeding the rats with 10% fructose solution for 8 consecutive weeks. The animals in the GQD treatment group were gavaged with GQD daily (18.2 g/kg/day) from the 5th to 8th week. Compared with control group, The IR rats showed significantly increases in water/food intakes, body weight and IR index at the ends of the 4th and 8th week. The fasted plasma glucose (FPG) level of the IR rats increased by the end of the 8th week. The GQD treatment lowered the IR index and normalized fecal metabonome by increasing the levels of propionate, acetate, succinate, taurine and glycerol, while decreasing the levels of n-butyrate, alanine and glutamate. These results indicated that the GQD treatment induced positive changes in amino acid metabolism, fatty acid oxidation and gut microbiota metabolism in the IR rats.