Tribological behaviors of Fe-Al-Cr-Nb alloyed layer deposited on 45 steel via double glow plasma surface metallurgy technique

Double glow plasma surface metallurgy technique was used to fabricate a Fe?Al?Cr?Nb alloyed layer onto the surface of the 45 steel. The microstructures and composition of th?eA Fl?eCr?Nb alloyed layer were analyzed by scanning electronic microscopy, X-ray diffraction and energy dispersive spectroscopy. The results indicate thatthe 20 μm alloyed layer is homogeneous and compact. The alloyed elements exhibit a gradient distribution along the cross section. Microhardness and nanoindentation tests imply that the surface hardness of the alloyed layer reaches HV 580, which is almost 2.8 times that of the substrate. Compared with the substrate, the alloyed layer has a much smaller displacement and a larger elastic modulus. According to the friction and wear tests at room temperature, the? FeAl?Cr?Nb alloyed layer has lower friction coefficient and less wear mass, implying that the Fe?Al?Cr?Nb alloyed layer can effectively improve the surface hardness and wear resistance of the substrate.

Light Simplified Cultivation Techniques of Wide Row and Double Ridge with Filming, Fertilizing and Sowing on One for Foxtail Millet

In view of the problems of completely depending on rain, low and unstable yield and complicated planting of dry land foxtail millet, the light simplified cultivation techniques of wide row and double ridge with filming, fertilizing and sowing on one for foxtail millet was formed through the integration of plastic film mulching technology and mechanized production technology by Institute of Millet crops of Hebei Academy of Agriculture and Forestry Sciences, and the techniques were introduced from the key technologies of pre-sowing preparation, sowing, supporting equipment, field management, harvesting, plastic film recycling.

Limit equilibrium method(LEM) of slope stability and calculation of comprehensive factor of safety with double strength-reduction technique

When the slope is in critical limit equilibrium(LE) state, the strength parameters have different contribution to each other on maintaining slope stability. That is to say that the strength parameters are not simultaneously reduced. Hence, the LE stress method is established to analyze the slope stability by employing the double strengthreduction(DSR) technique in this work. For calculation model of slope stability under the DSR technique, the general nonlinear Mohr–Coulomb(M–C) criterion is used to describe the shear failure of slope. Meanwhile, the average and polar diameter methods via the DSR technique are both adopted to calculate the comprehensive factor of safety(FOS) of slope. To extend the application of the polar diameter method, the original method is improved in the proposed method. After comparison and analysis on some slope examples, the proposed method's feasibility is verified. Thereafter, the stability charts of slope suitable for engineering application are drawn. Moreover, the studies show that:(1) the average method yields similar results as that of the polardiameter method;(2) compared with the traditional uniform strength-reduction(USR) technique, the slope stability obtained using the DSR techniquetends to be more unsafe; and(3) for a slope in the critical LE state, the strength parameter φ, i.e., internal friction angle, has greater contribution on the slope stability than the strength parameters c, i.e., cohesion.

Needle-knife fistulotomy vs double-guidewire technique in patients with repetitive unintentional pancreatic cannulations

AIM: To compare the success rates and adverse events of early needle-knife fistulotomy(NKF) and double-guidewire technique(DGT) in patients with repetitive unintentional pancreatic cannulations.METHODS: From a total of 1650 patients admitted for diagnostic or therapeutic endoscopic retrograde cholangiopancreatography(ERCP) at a single tertiary care hospital(Pusan National University Yangsan Hospital, Yangsan, South Korea) between January2009 and December 2012, 134(8.1%) patients with unsuccessful biliary cannulation after 5 min trial of conventional methods, together with 5 or more repetitive unintentional pancreatic cannulations, were enrolled in the study. Early NKF and DGT groups were assigned 67 patients each. In the DGT group, NKF was performed for an additional 7 min if successful cannulation was not achieved.RESULTS: The success rates with early NKF andthe DGT were 79.1%(53/67) and 44.8%(30/67)(P< 0.001), respectively. The incidence of post-ERCP pancreatitis(PEP) was lower in the early NKF group than in the DGT group [4.5%(3/67) vs 14.9%(10/67),P = 0.041]. The mean cannulation times in the early NKF and DGT groups after assignment were 257 s and312 s(P = 0.013), respectively.CONCLUSION: Our data suggest that early NKF should be considered as the first approach to selective biliary cannulation in patients with repetitive unintentional pancreatic cannulations.

Liquid Level Measurement in Oil Tanks Based on Double-differential Pressure Technique

The system principle and configuration of the double differential pressure method for measuring oil tank level are presented. The fundamental method and circuit of fiber optic transmission are analyzed .The accuracy and security of level measurement in the oil tanks have been greatly improved.

Minimally Invasive Surgical Technique in Double Aortic Arch with Distal Atretic Left-Side in Infant:From a Single-Surgeon Clinical Experience

Background:Double aortic arch(DAA)with distal left-sided aortic arch atresia(LAAA)can form complete vascular ring by ligamentum connection.We aimed to introduce an uncommon DAA-LAAA diagnosis and treatment by the minimally invasive surgical technique(MIST).Methods:We retrospectively reviewed 7 cases of DAA-LAAA that were treated from January 2017 to July 2021.All infant patients underwent surgical repair by minimally invasive surgical technique.Mean follow-up was 14.43 months(range,5–21 months).Results:There were seven patients with DAA-LAAA,including six males and one female.Median age was 19.29 months(range,9.0–29.0 months).Median weight was 11.30 kg(range,9.6–13.0 kg).Three patients were found severe tracheal compression by cardiac computed tomography angiography(cCTA).Six patients with isolated DAA-LAAA were performed operations through left subaxillary minithoracotomy,and one patient with ventricular septal defect(VSD)was performed operation concurrently under the cardiopulmonary bypass(CPB)through right subaxillary minithoracotomy.All patients had symptom improvement in the postoperative period and discharged successfully.Follow-up data showed good results in short-term.Conclusions:We introduce a new surgical pathway for DAA-LAAA treatment with good symptomatic relief in short-term.MIST is a safe,feasible and economical approach for infant patients.

The Double Projecting Neuron of the Cat Spinal Dorsal Horn——A Study with Double Retrograde Fluorescent Tracing Technique

The new double projecting neurons were found in the cat spinal dorsal horn by the double retrograde fluorescent tracing technique.Fast Blue(FB)was injected into unilateral dorsal column nucleus(DCN)of adult cats anesthetized with pentobarbital.Nuclear Yellow(NY)was injected ipsilaterally into the lateral cervical nucleus(LCN)8-9 days later.After an additional 18-30 hrs.

Construction of a model of autologous blood intracerebral hemorrhage in rats with a double injection and double needle withdrawal and the characteristics of the operative technique

BACKGROUND ： Experimental animal models of intracerebral hemorrhag （ICH） are greatly needed, so the process of establishment should be ideal in hematoma formation and easy to operate. OBJECTIVE ： To construct model of ICH in rats with double injection of autologous blood taken from the cut tail cut and double withdrawal of the needle （shortened as two-step injection model）, and compare with those induced by single and double injections. DESIGN ： A randomized controlled tria SETTING： Department of Neurology, General Hospital of Military Area Command of Chinese PLA. MATERIALS： Thirty male Wistar rats of 10 to 12 months, weighing （400±25） g, provided by the Experimental Center of Medical Animals, General Hospital of Shenyang Military Area Command of Chinese PLA, were divided randomly into 3 groups with 10 rats in each group： two-step injection group, single injection group, double injection group. METHODS ： The experiment was carried out in the Department of Neurology, General Hospital of Military Area Command of Chinese PLA from March to June in 2004. Autologous blood ICH model in rats were established as follows： In the two-step injection group, 50 μL unclotted autologous blood was taken from the rat tail cut, then injected with microsyringe into the caudate nucleus, 10 μL injected at first, paused for 2 minutes, and then the rest 40 μL injected slowly and continuously within 2 minutes. After the injection, the needle was kept immovable for about 4 minutes, withdrawn 2.0 mm, again kept immovable for about 4 minute, and then removed wholly at a slow speed. In the single injection group, 50 μL unclotted tail blood was injected slowly and continuously all within 2 minutes and the needle was slowly removed;（4） In the double injection group, 10 mL blood was injected at first, paused for 2 minutes, the rest 40 μL injected evenly within 2 minutes, and then the needle was withdrawn slowly and uninterruptedly. Neurologic findings were scored in accordance with Longa＇s five-point scale （0-4 scores, the higher the score, the severer the neurological dysfunction）. The rats were killed to remove and sections were prepared, the morphological features of hematomas were grossly observed, the maximal diameter and size of hematomas in each slice were measured with the imaging analytical system, and the volume was calculated. Meanwhile, the conveniences of the techniques were compared. MAIN OUTCOME MEASURES： The morphological features and volume of hematomas, neurologic deficit score （NDS）, and the convenience of the techniques were compared. RESULTS： All the 30 rats were involved in the analysis of results without deletion. （1） Results of the morphological observation of volume of hematoma： In the two-step injection group, hematomas located in the right caudate nucleus area regularly in circular or analogously circular shape in each slice. The formation rate of hematomas in the single injection group and double injection group were lower than those in the two-step injection group [60% （6/10）, 80% （8/10）, 100% （10/10）, P〈 0.01, 0.05]. The volume of hematomas in the single injection group and double injection group were smaller than those in the two-step injection group [（28.5±14.8）, （33.4±7.4）, （41.6±3.9） mm3, P〈 0.01, 0.05]. （2） NDS results： The NDS scores in the single injection group and double injection group were smaller than that in the two-step injection group （0.90±0.83, 1.30±0.78, 1.90±0.57, P〈 0.05）. （3）Comparison of the convenience of the techniques： The double injection method allowed generating reproducible hematomas in rats with shortcomings that it needed autologous arterial blood from femoral artery, and precision instruments such as microinfusion pump. The two-step injection injected fresh unclotting blood taken directly from the tail cut with microsyringe into the rat brain, and it has the advantages of easy operation, no influence on the activity of thrombase, shorter duration for model establishment, and higher rate of hematoma formation, which could generate ideal and economical models of ICH. The two-step injection induced hemotoma regularly in circular or analogously circular shape in each slice, but those induced by single and double injections were mostly in strip or fusiform shapes and extending along the needle tracks or into the ventricle or subarachnoid space. CONCLUSION ： The autologous blood ICH model induced by the two-step injection method is a reproducible and reliable one in regular shape, which is better than those induced by double and single injections.

Nutrition Bowl"Double Covering"Cutting Propagation Technique for Llex cornuta var.fortunei S.Y.Hu

Llex cornuta var.fortunei S.Y.Hu is a good ornamental tree species for viewing fruits and leaves,and has a wide range of garden uses.Nutrition bowl cutting seedlings can improve the survival rate of L.cornut a var.fortunei S.Y.Hu transplanting and greening,and has the advantages of no time limit for planting and saving management costs.Based on this,this paper introduced the container seedling double-covering cutting technology for L.cornut a var.fortunei,to provide a reference for the propagation of L.cornut a var.fortunei.

Endovascular Application of Magnetic Resonance Double Mismatch Technique for Acute Anterior Circulation Large Vessel Occlusion with Cerebral Infarction in an Unknown Time Window

Objective:To investigate the clinical effects of applying the magnetic resonance double mismatch technique to endovascular treatment of acute anterior circulation,large vessel occlusion with cerebral infarction in an unknown time window.Methods:The research work was carried out in our hospital,the work was carried out from November 2018 to November 2019,the patients with acute anterior circulation large vessel occlusion with cerebral infarction who were treated in our hospital during this period,100 patients,50 patients with an unknown time window and 50 patients with definite time window were selected,and they were named as the experimental and control groups,given different examination methods,were given to investigate the clinical treatment effect.Results:Patients’data on HIHSS score before treatment,the incidence of intracranial hemorrhage and rate of Mrs≤2 rating after 90 days of treatment were not significantly different(P>0.05),which was not meaningful.The differences in data between the two groups concerning HIHSS scores were relatively significant before,and after treatment(P<0.05).Conclusion:The magnetic resonance double mismatch technique will be applied in the endovascular treatment of acute anterior circulation large vessel occlusion with cerebral infarction of unknown time window.

Double tractors swing microendoscopic discectomy technique for multi-segmental lumbar disc herniation

Objective To evaluate the effect of double tractors swing microendoscopic discectomy technique in multisegmental lumbar disc herniation.Methods From December 2006 to November 2009,153 patients with multisegmental lumbar disc herniation

Solving the AKNS Hierarchy by Its Bilinear Form: Generalized Double Wronskian Solutions

Through the Wronskian technique, a simple and direct proof is presented that the AKNS hierarchy in the bilinear form has generalized double Wronskian solutions. Moreover, by using a unified way, soliton solutions, rational solutions, Matveev solutions and complexitons in double Wronskian form for it are constructed.

Double Glow Plasma Hydrogen-free Carburizing on Commercial Purity Titanium

A carburized layer with special physical and chemical properties was formed on the surface of commercial purity titanium by a double glow plasma hydrogen-free carburizing technique,High-purity netlike solid graphite was used as a raw material and commercial purity titanium was used as the substrate material.Argon gas was used as the working gas.The carburized layer can be obviously observed under a microscope.X-ray diffraction indicates that TiC phase with higher hardness and dissociate state carbon phase was formed in the carburized layer.The glow discharge spectrum（GDS） analysis shows that the carbon concentration distributes grodiently along the depth of carburized layer.The surface hardness of the substrate increases obviously.The hardness distributes gradiently from the surface to inner of carburized layer.The friction coefficient reduces by more than 1/2,the ratio wear rate decreases by above three orders of magnitude.The wear resistance of the substrate material is improved-consumedly.

Magnetic resonance imaging-based deep learning model to predict multiple firings in double-stapled colorectal anastomosis

BACKGROUND Multiple linear stapler firings during double stapling technique(DST)after laparoscopic low anterior resection(LAR)are associated with an increased risk of anastomotic leakage(AL).However,it is difficult to predict preoperatively the need for multiple linear stapler cartridges during DST anastomosis.AIM To develop a deep learning model to predict multiple firings during DST anastomosis based on pelvic magnetic resonance imaging(MRI).METHODS We collected 9476 MR images from 328 mid-low rectal cancer patients undergoing LAR with DST anastomosis,which were randomly divided into a training set(n=260)and testing set(n=68).Binary logistic regression was adopted to create a clinical model using six factors.The sequence of fast spin-echo T2-weighted MRI of the entire pelvis was segmented and analyzed.Pure-image and clinical-image integrated deep learning models were constructed using the mask region-based convolutional neural network segmentation tool and three-dimensional convolutional networks.Sensitivity,specificity,accuracy,positive predictive value(PPV),and area under the receiver operating characteristic curve(AUC)was calculated for each model.RESULTS The prevalence of≥3 linear stapler cartridges was 17.7%(58/328).The prevalence of AL was statistically significantly higher in patients with≥3 cartridges compared to those with≤2 cartridges(25.0%vs 11.8%,P=0.018).Preoperative carcinoembryonic antigen level>5 ng/mL(OR=2.11,95%CI 1.08-4.12,P=0.028)and tumor size≥5 cm(OR=3.57,95%CI 1.61-7.89,P=0.002)were recognized as independent risk factors for use of≥3 linear stapler cartridges.Diagnostic performance was better with the integrated model(accuracy=94.1%,PPV=87.5%,and AUC=0.88)compared with the clinical model(accuracy=86.7%,PPV=38.9%,and AUC=0.72)and the image model(accuracy=91.2%,PPV=83.3%,and AUC=0.81).CONCLUSION MRI-based deep learning model can predict the use of≥3 linear stapler cartridges during DST anastomosis in laparoscopic LAR surgery.This model might help determine the best anastomosis strategy by avoiding DST when there is a high probability of the need for≥3 linear stapler cartridges.

Can trans-anal reinforcing sutures after double stapling in lower anterior resection reduce the need for a temporary diverting ostomy?

AIM:To evaluate trans-anal reinforcing sutures in low anterior resection using the double-stapled anastomosis technique for primary rectal cancers performed at a single institution.METHODS:The data of patients who received transanal reinforcing sutures were compared with those of patients who did not receive them after low anterior resection.Patients who underwent laparoscopic low anterior resection and the double-stapled anastomosis technique for primary rectal cancer between January2008 and December 2011 were included in this study.Patients with no anastomosis,a hand-sewn anastomosis,high anterior resection,or preoperative chemoradiation were excluded.The primary outcomes measured were the incidence of postoperative anastomotic complications and placement of a diverting ileostomy.RESULTS:Among 110 patients,the rate of placement of a diverting ileostomy was significantly lower in the suture group(SG)compared with the non-suture control group(CG)[SG,n=6(12.8%);CG,n=19(30.2%),P=0.031].No significant difference was observed in the rate of anastomotic leakage[SG,n=3(6.4%);CG,n=5(7.9%)].CONCLUSION:Trans-anal reinforcing sutures may reduce the need for diverting ileostomy.A randomized prospective study with a larger population should be performed in the future to demonstrate the efficacy of trans-anal reinforcing sutures.

Double Wronskian Solutions of Non-Isospectral Levi Equations

The double Wronskian solutions of the non-isospectral Levi equations are derived through Wronskian technique.

Influences of double diffusion upon radiative flow of thin film Maxwell fluid through a stretching channel

This work explores the influence of double diffusion over thermally radiative flow of thin film hybrid nanofluid and irreversibility generation through a stretching channel.The nanoparticles of silver and alumina have mixed in the Maxwell fluid(base fluid).Magnetic field influence has been employed to channel in normal direction.Equations that are going to administer the fluid flow have been converted to dimension-free notations by using appropriate variables.Homotopy analysis method is used for the solution of the resultant equations.In this investigation it has pointed out that motion of fluid has declined with growth in magnetic effects,thin film thickness,and unsteadiness factor.Temperature of fluid has grown up with upsurge in Brownian motion,radiation factor,and thermophoresis effects,while it has declined with greater values of thermal Maxwell factor and thickness factor of the thin film.Concentration distribution has grown up with higher values of thermophoresis effects and has declined for augmentation in Brownian motion.

空心螺钉技术与可吸收性锚钉Double-Pulley技术治疗后交叉韧带胫骨止点撕脱骨折的临床疗效比较

目的比较空心螺钉技术与可吸收性锚钉Double-Pulley技术治疗后交叉韧带(PCL)胫骨止点撕脱骨折的临床疗效。方法选取2013年1月至2019年7月本院收治的120例PCL胫骨止点撕脱骨折患者作为研究对象,根据手术方法不同分为空心螺钉技术组与Double-Pulley技术组,每组60例。空心螺钉技术组采用空心螺钉固定治疗,Double-Pulley技术组采用可吸收锚钉Double-Pulley固定治疗,比较两组手术时间、切口长度、术中出血量、内固定失效率、术后并发症发生率、住院时间、患者满意度、屈曲活动度、Lysholm评分及视觉模拟评分法(VAS)评分。结果两组术中出血量比较差异无统计学意义;Double-Pulley技术组手术时间、切口长度均短于空心螺钉技术组,差异有统计学意义(P<0.05)。两组内固定失效率、术后并发症发生率比较差异无统计学意义;Double-Pulley技术组住院时间短于空心螺钉技术组,患者满意度高于空心螺钉技术组,差异有统计学意义(P<0.05)。Double-Pulley技术组屈曲活动度大于空心螺钉技术组,Lysholm评分高于空心螺钉技术组,VAS评分低于空心螺钉技术组,差异有统计学意义(P<0.05)。结论使用可吸收锚钉Double-Pulley技术固定PCL胫骨止点撕脱骨折,更有利于患者恢复膝关节功能,减少并发症,缩短住院时间,不需二次手术取出内固定物,提高患者的满意度,值得临床推广应用。

High-temperature investigation of mould slag crystallization by single and double hot thermocouple techniques

Methods for the characterization of mould slag crystallization with special emphasis on the single/double hot thermocouple technique(SHTT/DHTT)are reviewed.In the continuous casting process of steels,horizontal heat transfer is mainly influenced by the crystallization behaviour of the mould flux film.Here,both precipitation of crystals out of a liquid phase and devitrification of the glassy film in contact with the mould are of main interest.Therefore,various investigation methods are implemented to characterize different slag properties related to crystallization:a viscometer for determining the break temperature,differential thermal analysis(DTA),confocal scanning laser microscopy,and the water-cooled copper finger test.For near-service conditions,DHTT reveals the most detailed information,including not only the crystallization or devitrification temperature but also the morphology as well as the crystallization velocity.Due to improvements in the device and the representation of the results,a comparison of different samples is possible.Nevertheless,the application field of SHTT/DHTT is restricted to slag systems with low contents of evaporating components.Furthermore,the time required for data analysis is significantly longer than that required for other methods,e.g.DTA.Therefore,the application of DHTT is mainly advisable for mould slag research and development,whereas DTA can also be used for incoming inspections.

Electrochemical deposition of uranium oxide with an electrocatalytically active electrode using double potential step technique

The development of effective uranium-removal techniques is of great significance to the environment and human health.In this work,a double potential step technique(DPST)was applied to remove U(VI)from uranium-containing wastewater using a carbon felt electrode modified by graphene oxide/phytic acid composite(GO-PA@CF).The application of DPST can inhibit water splitting and prevent GO-PA from adsorbing other interfering ions in wastewater.The GO-PA composite can effectively accelerate the electrochemical reduction rate of U(VI),which significantly improved the electrochemical deposition rate of uranium oxide.As a result,the maximum removal efficiency and maximum removal capacity of GOPA@CF electrode reached 98.7%and 1149.3 mg/g,respectively.The removal efficiency remained 97.2%after five cycles of reuse.Moreover,the removal efficiency of GO-PA@CF electrode can reach more than 70%in simulated wastewater.