Research on batch multielement rapid quantitative analysis based on the standard curve-assisted calibration-free laserinduced breakdown spectroscopy method

This study proposes a batch rapid quantitative analysis method for multiple elements by combining the advantages of standard curve(SC)and calibration-free laser-induced breakdown spectroscopy(CF-LIBS)technology to achieve synchronous,rapid,and accurate measurement of elements in a large number of samples,namely,SC-assisted CF-LIBS.Al alloy standard samples,divided into calibration and test samples,were applied to validate the proposed method.SC was built based on the characteristic line of Pb and Cr in the calibration sample,and the contents of Pb and Cr in the test sample were calculated with relative errors of 6%and 4%,respectively.SC built using Cr with multiple characteristic lines yielded better calculation results.The relative contents of ten elements in the test sample were calculated using CF-LIBS.Subsequently,the SC-assisted CF-LIBS was executed,with the majority of the calculation relative errors falling within the range of 2%-5%.Finally,the Al and Na contents of the Al alloy were predicted.The results demonstrate that it effectively enables the rapid and accurate quantitative analysis of multiple elements after a single-element SC analysis of the tested samples.Furthermore,this quantitative analysis method was successfully applied to soil and Astragalus samples,realizing an accurate calculation of the contents of multiple elements.Thus,it is important to advance the LIBS quantitative analysis and its related applications.

Application of Choquet Integral-Importance-Performance Analysis and TOPSIS Methods in Approaching the Preference Factors of Calligraphy and Seal Engraving Imagery

Classical Chinese characters,presented through calligraphy,seal engraving,or painting,can exhibit different aesthetics and essences of Chinese characters,making them the most important asset of the Chinese people.Calligraphy and seal engraving,as two closely related systems in traditional Chinese art,have developed through the ages.Due to changes in lifestyle and advancements in modern technology,their original functions of daily writing and verification have gradually diminished.Instead,they have increasingly played a significant role in commercial art.This study utilizes the Evaluation Grid Method(EGM)and the Analytic Hierarchy Process(AHP)to research the key preference factors in the application of calligraphy and seal engraving imagery.Different from the traditional 5-point equal interval semantic questionnaire,this study employs a non-equal interval semantic questionnaire with a golden ratio scale,distinguishing the importance ratio of adjacent semantic meanings and highlighting the weighted emphasis on visual aesthetics.Additionally,the study uses Importance-Performance Analysis(IPA)and Technique for Order Preference by Similarity to Ideal Solution(TOPSIS)to obtain the key preference sequence of calligraphy and seal engraving culture.Plus,the Choquet integral comprehensive evaluation is used as a reference for IPA comparison.It is hoped that this study can provide cultural imagery references and research methods,injecting further creativity into industrial design.

Numerical Analysis of a Spiral-groove Dry-gas Seal Considering Micro-scale Effects

A dry-gas seal system is a non-contact seal technology that is widely used in different industrial applications.Spiral-groove dry-gas seal utilizes fluid dynamic pressure effects to realize the seal and lubrication processes,while forming a high pressure gas film between two sealing faces due to the deceleration of the gas pumped in or out.There is little research into the effects and the influence on seal performance,if the grooves and the gas film are at the micro-scale.This paper investigates the micro-scale effects on spiral-groove dry-gas seal performance in a numerical solution of a corrected Reynolds equation.The Reynolds equation is discretized by means of the finite difference method with the second order scheme and solved by the successive-over-relaxation（SOR） iterative method.The Knudsen number of the flow in the sealing gas film is changed from 0.005 to 0.120 with a variation of film depth and sealing pressure.The numerical results show that the average pressure in the gas film and the sealed gas leakage increase due to micro-scale effects.The open force is enlarged,while the gas film stiffness is significantly decreased due to micro-scale effects.The friction torque and power consumption remain constant,even in low sealing pressure and spin speed conditions.In this paper,the seal performance at different rotor face spin speeds is also described.The proposed research clarifies the micro-scale effects in a spiral-groove dry-gas seal and their influence on seal performance,which is expected to be useful for the improvement of the design of dry-gas seal systems operating in the slip flow regime.

Tribological Properties and Failure Analysis of PTFE Composites used for Seals in the Transmission Unit

The sealing rings are one of the most important components as the sealing devices in the wet clutch unit of a heavy vehicle. The sealing ring, made from PTFE composites, was subjected to serious wear on the sealing surface, but the mating metal surface only had slight abrasion. A specialized test rig was designed for wear research and failure analysis of the sealing ring. The composition analyses of the ring material, working conditions and wear surface characteristics by visual inspection and tribological properties as well as microscopic analysis with scanning electron microscope was performed to determine the wear mechanism and failure causes. Results revealed that the wear of PTFE composites was characterized by abrasion and adhesion after a certain duration testing, and the wear mechanism changed to thermal fatigue and abrasive wear in the stage of intense wear. The thermal deformation and fatigue were primarily responsible for the rapid wear of the PTFE composites for the sealing rings.

Architecture design and demand analysis on application layer of standard system for ubiquitous power Internet of Things

The ubiquitous power Internet of Things(UPIoT)is an intelligent service system with comprehensive state perception,efficient processing,and flexible application of information.It focuses on each link of the power system and makes full use of the mobile internet,artificial intelligence,and other advanced information and communication technologies in order to realize the inter-human interaction of all things in all links of the power system.This article systematically presents to the national and international organizations and agencies in charge of UPIoT layer standardization the status quo of the research on the Internet of Things(IoT)-related industry standards system.It briefly describes the generic standard classification methods,layered architecture,conceptual model,and system tables in the UPIoT application layer.Based on the principles of inheritance,innovation,and practicability,this study divides the application layer into customer service,power grid operation,integrated energy,and enterprise operation,emerging business and analyzes the standard requirements of these five fields.This study also proposes a standard plan.Finally,it summarizes the research report and provides suggestions for a follow-up work.

Impact of Different Grinding Aids on Standard Deviation in X-Ray Fluorescence Analysis of Cement Raw Meal

X-ray fluorescence (XRF) analysis utilizes particle size which is resulted from milling of a material. The milling ensures uniform and fine grained powder. The finer and more uniform the particle size is, the better the result and easier it is for material quality control. To ensure uniformity in particle size and finer powder, a comparative analysis was conducted with different grinding aids and pressed pellet method was used in obtaining analysis results. Pressed pellets of cement raw meal sample milled with different grinding aids (graphite, aspirin and lithium borate) were subjected to XRF. Graphite produced better particle size uniformity with a corresponding standard deviation that made quality control of raw meal easier and better than aspirin and lithium borate.

Analysis of the sealing performance of combined sealing structure under deep-sea high pressure environment

For the requirement of safe and stable operation,the combined sealing structure was used for reciprocating motion in the deep sea high-pressure environment,and the effects of different seawater depths and shaft movement speed on the sealing performance of the combined sealing structure were studied.The change rule of the sealing performance of the combined sealing structure of reciprocating motion under different working conditions is proved.The study shows that in the combined sealing structure of reciprocating movement,the Von Mises stress and the contact stress of the O-ring varies with the direction of the shaft movement.The Von Mises stress and contact stress of the O-ring,the Von Mises stress and the contact stress on each sealing lip of the slip ring gradually increase with the increasing of seawater depths.At the same time,the Von Mises stress of the O-ring which in the process of the shaft upward movement is greater than the shaft downward movement,making the shaft upward movement more likely to cause the O-ring relaxation and fatigue.The shaft movement speed has no significant influence on the Von Mises stress and contact stress of the O-ring.The research results provide theoretical guidance and technical support for the selection and optimization of the geometrical parameters of the combined sealing structure in the deep-sea high-pressure environment.

Effect and sensitivity analysis of the rotational speed on the fluid-induced force characteristics of the straight-through labyrinth gas seal

The effects of the rotational speed on the fluid-induced force characteristics of a straight-through labyrinth gas seal( STLGS) are numerically investigated using the steady computational fluid dynamics( CFD) method based on a three-dimensional model of the STLGS. The fluid-induced force characteristics of the STLGS for five rotational speeds at a pressure drop of △P = 5000 Pa with and without eccentricity are computed. The grid density analysis ensures the accuracy of the present steady-CFD method. The effect and sensitivity analysis show that the changes in rotational speed affect the pressure forces,viscous forces and total pressure distributions on the rotor surface,velocity streamlines,leakage flow rates,and maximum flow velocities. The results indicate that the rotational speed inhibits the pressure forces,leakage flow rates and maximum flow velocities and promotes the viscous forces and total pressure on the rotor surface.

3D TRANSIENT COUPLED THERMOELASTIC-PLASTIC CONTACT SEALING ANALYSIS OF REACTOR PRESSURE VESSEL

Sealing analysis of sealing system in reactor pressure vessels is relevant with multiple nonlinear coupled-field effects, so even large-scale commercial finite element software cannot finish the complicated analysis. A finite element method of 3D transient coupled thermo-elastic-plastic contact sealing analysis for reactor pressure vessels is presented, in which the surface nonlinearity, material nonlinearity, transient heat transfer nonlinearity and multiple coupled effect are taken into account and the sealing equation is coupling solved in iterative procedure. At the same time, a computational analysis program is developed, which is applied in the sealing analysis of experimental reactor pressure vessel, and the numerical results are in good coincidence with the experimental resuits. This program is also successful in analyzing the practical problem in engineering.

Application of a Modified Arrhenius Equation to Describe the Time-Temperature Equivalence in Relaxation Analysis of Metal Seals

For the application of the time-temperature superposition principle a suitable relation is needed to describe the time-temperature shift factor a. Therefore, the Arrhenius equation is widely used due to its simple form and often leads to suitable results. Where, the Arrhenius equation presents a linear relation for the temperature-dependent shift factor in logarithmic scale ln（α） with the absolute inverse temperature （1/θ）. However, in cases with a large temperature range which eventually include more complex reaction processes, the functional relation between ln（α） and （1/θ） is nonlinear in the ＇Arrhenius plot＇. In those cases, the monotone change of the nonlinear range in the ＇Arrhenius plot＇ can be interpreted as a transient range between two approximately linear or constant regions. An extended application of the modified Arrhenius equation from Nakamura （1989） is presented in this study for this transient range. The introduced method was applied to describe the time-temperature equivalence in the relaxation analysis of restoring seal force of metal seals, which are used in lid-systems of transport and interim storage casks for radioactive materials. But, the method is widely valid and can be used for different objectives which are characterized by thermorheologically simple behavior with nonlinear sensitivity to inverse temperature.

Magnetic endoscopic imaging vs standard colonoscopy:Meta-analysis of randomized controlled trials

AIM:To assess the theoretical advantages of magnetic endoscope imaging(MEI)over standard colonoscopies(SCs)and to compare their efficacies.METHODS:Electronic databases,including PubMed,EMBASE,the Cochrane library and the Science Citation Index,were searched to retrieve relevant trials.In addition,abstracts from papers presented at professional meetings and the reference lists of retrieved articles were reviewed to identify additional studies.The metaanalyses were performed using RevMan 5.1.A random effect model with the Mantel-Haenszel method was used for pooling dichotomous and continuous data.A sensitivity analysis was performed by excluding the trials with a small number of patients and by excluding the trials performed by inexperienced providers.RESULTS:Eight randomized controlled trials(RCTs),including 2967 patients,were included in the metaanalysis to compare cecal intubation rates and times,sedation dose,abdominal pain scores and the use of ancillary maneuvers between MEI and SC.The overall OR was 1.92(95%CI:1.13-3.27,eight RCTs),as indicated by the cecal intubation rate of MEI compared with SC,but MEI did not have any distinct advantage over SC for cecal intubation time(MD=-0.07,95%CI:-0.16-0.02;three RCTs).MEI did not generally result in lower pain scores.Outcomes were also analyzed for the two subgroups based on the endoscopists’experience level to evaluate cecal intubation rates.MEI presented better outcomes for non-experienced colonoscopists than experienced colonoscopists.CONCLUSION:The real-time magnetic imaging system is of benefit in training and educating inexperienced endoscopists and improves the cecal intubation rate for experienced and inexperienced endoscopists.

Standardization of proton-induced x-ray emission technique for analysis of thick samples

This paper describes the standardization of the proton-induced x-ray emission（PIXE） technique for finding the elemental composition of thick samples. For the standardization, three different samples of standard reference materials（SRMs） were analyzed using this technique and the data were compared with the already known data of these certified SRMs. These samples were selected in order to cover the maximum range of elements in the periodic table. Each sample was irradiated for three different values of collected beam charges at three different times. A proton beam of 2.57 Me V obtained using 5UDH-II Pelletron accelerator was used for excitation of x-rays from the sample. The acquired experimental data were analyzed using the GUPIXWIN software. The results show that the SRM data and the data obtained using the PIXE technique are in good agreement.

Estimation of Standard Operation Time of Flight Legs Based on Clustering and Probability Analysis

A clustering algorithm and a probability statistics method were applied to different phases of a flight to analyze operation time during aircraft ground taxiing and airborne flight.And the clustering pattern,distribution characteristics and dynamically changing rules of the two phases were identified.Further,an estimate method was established to measure operation time of flight legs,with creative steps of calculating individual segment separately and then integrating them accordingly.The method can both objectively and dynamically measure operation time,and accurately reflect real situation.It helps to better utilize airport slot resources and provides a strong support for air traffic flow management when scheduling flight plan in strategic and pre-tactic phases.

Comparison of Dose-dense ABVD and Standard ABVD in the Treatment of Early Unfavorable and Advanced Hodgkin's Lymphoma: A Retrospective Analysis

This retrospective analysis compared standard regimen of doxorubicin, bleomycin, vin- blastine, and dacarbazine （ABVD） with the dose-dense ABVD regimen （ABVD-21） in terms of effi- cacy and toxicity. Patients who had early-stage unfavorable or advanced Hodgkin＇s lymphoma （HL） according to German Hodgkin Study Group criteria from March 1999 to February 2011 were ana- lyzed for treatment response, long-term survival and hematological toxicity. There were 85 patients in the ABVD-21 group and 118 patients in the ABVD group respectively. The complete remission rates aider completion of treatment were 92.9% and 90.7% for ABVD-21 and ABVD, respectively. During a median follow-up period of 62 months, no significant difference was found in projected 10-year progression-free survival （PFS） and overall survival （OS） rates （84.7% and 94.1% respectively for ABVD-21; 81.4% and 91.5% for ABVD）. Subgroup analyses showed that ABVD-21 was signifi- cantly better than ABVD for patients with IPS〉3 in terms of PFS and OS rates. Grade 3 to 4 leuko- penia （51.8% vs. 28.8%, P=0.001） and neutropenia （57.6% vs. 39.0%, P=0.009） were more common with ABVD-21. We were led to conclude that dose-dense ABVD did not result in better tumor con- trol and overall survival than did ABVD for early-stage unfavorable HL. However, patients at high risk, for example, with IPS〉3, may benefit from dose-dense ABVD.

Boundary Value Problems for Burgers Equations, through Nonstandard Analysis

In this paper we study inviscid and viscid Burgers equations with initial conditions in the half plane . First we consider the Burgers equations with initial conditions admitting two and three shocks and use the HOPF-COLE transformation to linearize the problems and explicitly solve them. Next we study the Burgers equation and solve the initial value problem for it. We study the asymptotic behavior of solutions and we show that the exact solution of boundary value problem for viscid Burgers equation as viscosity parameter is sufficiently small approach the shock type solution of boundary value problem for inviscid Burgers equation. We discuss both confluence and interacting shocks. In this article a new approach has been developed to find the exact solutions. The results are formulated in classical mathematics and proved with infinitesimal technique of non standard analysis.

Similarity Analysis-based Component Standardization for Product Family Design

During the product family design, it is necessary to reduce the variety of components and share common components among many products. The major benefits are lessened design efforts and reduced costs. Therefore, this paper presents an approach to standardize components of a product family. Form feature modeling for components is discussed. Based on the similarity analysis, a step by step method to standardize the feature architectures of components is described. The algorithms for standardization are identified as well. A case for standardizing components of an auto-body family is used to demonstrate the validity of this approach.

New insights on the standardization of peripheral nerve regeneration quantitative analysis

Peripheral nerves form a complex network connecting the central nervous system and the body. Injuries to peripheral nerves often lead to partial or complete loss of motor, sen- sory and autonomic functions, thus interfering with many aspects of an individual＇s life.

Analysis of Factors Affecting Sealing Performance of Subsea Wellhead Connector

Subsea wellhead connector is the key equipment for offshore oil and gas production. The working water depth is generally more than 500 m, so it has higher requirements for its sealing performance. In this paper, the VX gasket matched with H-4 subsea wellhead connector is taken as the research object, and the mechanical analysis under preload and production conditions is carried out. The finite element model of subsea wellhead connector is established by ABAQUS software, and the influence of axial preload, production pressure and material properties on the sealing performance of VX gasket is studied. The results show that the greater the axial preload, the greater the contact stress on the gasket surface;the contact stress decreases first and then increases linearly with the increase of production pressure;the material properties of the gasket are also an important factor affecting its sealing performance, 316L stainless steel is more suitable for gasket material than 304 stainless steel and Inconel625.

Spatio-Temporal Analysis of Drought in the North-Eastern Coastal Region of Vietnam Using the Standardized Precipitation Index (SPI)

Spatio-temporal analysis of drought provides valuable information for drought management and damage mitigation. In this study, the Standardized Precipitation Index at the time scale of 6 months (SPI-6) is selected to reflect drought conditions in the North-Eastern coastal region of Vietnam. The drought events and their characteristics from 1981 to 2019 are detected at 9 meteorological stations and 10 Chirps rainfall stations. The spatio-temporal variation of drought in the study region is analyzed on the basis of the number, duration, severity, intensity, and peak of the detected drought events at the 19 stations. The results show that from 1981 to 2019 the drought events mainly occurred with 1-season duration and moderate intensity and peak. The number, duration, severity, and peak of the drought events were the greatest in the period 2001-2010 and were the smallest in the period 2011-2019. Among the 19 stations, the drought duration tends to decrease at 11 stations, increase at 7 stations, and has a slight variant at 1 station;the drought severity tends to decrease at 14 stations, increase at 4 stations, and has not a significant trend at 1 station;the drought intensity tends to decrease at 17 stations, increase at 1 station, and has a slight variant at 1 station;and the drought peak tends to decrease at 18 stations and increase at 1 station.

Analysis of the national standard for safety requirements of fuel cell electric vehicles

In order to meet new challenges brought by the development of fuel cell electric vehicle(FCEV)industry,we are in urgent need to update and refine the safety requirements for FCEVs.To this end,GB/T 24549-2020,Fuel cell electric vehicles-Safety requirements,was issued on September 29,2020.This paper analyzes the main technical content of the standard as well as its similarities and differences with the 2009 Version.