Interface property of dissimilar Ti-6Al-4V/AA1050 composite laminate made by non-equal channel lateral co-extrusion and heat treatment

The purpose of this paper is to examine the effect of processing parameters and subsequent heat treatments on the microstructures and bonding strengths of Ti-6Al-4V/AA1050 laminations formed via a non-equal channel lateral co-extrusion process.The microstructural evolution and growth mechanism in the diffusion layer were discussed further to optimize the bonding quality by appropriately adjusting process parameters.Scanning electron microscopes(SEM),energy dispersive spectrometer(EDS),and X-ray diffraction(XRD)were used to characterize interfacial diffusion layers.The shear test was used to determine the mechanical properties of the interfacial diffusion layer.The experimental results indicate that it is possible to co-extrusion Ti-6Al-4V/AA1050 compound profiles using non-equal channel lateral co-extrusion.Different heat treatment processes affect the thickness of the diffusion layer.When the temperature and time of heat treatment increase,the thickness of the reaction layers increases dramatically.Additionally,the shear strength of the Ti-6Al-4V/AA1050 composite interface is proportional to the diffusion layer thickness.It is observed that a medium interface thickness results in superior mechanical performance when compared to neither a greater nor a lesser interface thickness.Microstructural characterization of all heat treatments reveals that the only intermetallic compound observed in the diffusion layers is TiAl_(3).Due to the inter-diffusion of Ti and Al atoms,the TiAl_(3) layer grows primarily at AA1050/TiAl_(3) interfaces.

高迁移率族蛋白B1在类风湿关节炎中的表达水平研究

目的探讨高迁移率族蛋白B1(HMGB1)在类风湿关节炎中的表达。方法选取2017年5月-2018年5月在吉林大学第一医院行关节置换术或滑膜清理术的类风湿关节炎患者49例作为研究组;另选取该院同期行手术治疗的骨关节炎患者30例作为对照组。所有研究对象入院后第3天清晨空腹采集外周静脉血,分离血清,采用酶联免疫吸附法测定HMGB1含量;取保存的所有研究对象的病损关节滑膜组织石蜡病理切片标本,采用链霉菌抗生物素蛋白-过氧化物酶连结(SP)法检测HMGB1的表达。结果研究组血清HMGB1水平高于对照组(P<0.05)。研究组HMGB1阳性表达率高于对照组(P<0.05)。研究组SP法染色评分高于对照组(P <0.05)。结论 HMGB1在类风湿关节炎中高表达,其可能在类风湿关节炎组织损伤发生、发展中发挥重要作用,可作为类风湿关节炎辅助诊断指标之一。

Long-term follow-up of HCV patients with sustained virological response after treatment with pegylated interferon plus ribavirin

Background:The progress of liver diseases may not stop after viral eradication.This study aimed to provide data on long-term prognosis of patients with hepatitis C virus(HCV)infection who underwent pegylated interferon plus ribavirin(PR)regimen and achieved a sustained virological response 24 weeks post-treatment(SVR24).Methods:Responders to the PR regimen in our hospital from January 2011 to June 2014 were enrolled and prospectively followed up.Baseline characteristics were profiled.The incidence of hepatocellular carcinoma(HCC),progression of liver disease(increase in liver stiffness or occurrence of decompensated complication),and HCV recurrence was all monitored.The accumulative and annualized incidence rates(AIRs)of these adverse events were analyzed,and the risk factors were also examined.Results:In total,151 patients reached a median follow-up time of 103 weeks.Among them,two had an incidence of HCC during the surveillance with AIR of 0.68%(95%CI:0.00-1.63%).Six patients showed progression of liver disease with AIR of 2.05%(95%CI:0.42%-3.68%).Three patients who had risky behaviors encountered HCV reinfection.The cirrhotic patients faced higher risk of poor prognosis than non-cirrhotic patients,including HCC and progression of liver disease(AIR:6.17%vs.1.42%,P=0.039).Conclusions:The incidence of HCC and progression of liver disease was evident in PR responders during the long-term follow-up period,but the risk level was low.Cirrhotic responders were more vulnerable to develop HCC post SVR24 compared with non-cirrhotic ones.HCV recurrence was rare in responders with SVR24 who had corrected their risky behaviors.

MicroRNA-494对胃癌细胞增殖、细胞周期及凋亡的影响

目的探讨microRNA-494(miR-494)对胃癌细胞增殖、细胞周期及凋亡的影响。方法选取2015年1月—2018年1月被陕西省肿瘤医院收治并行手术切除的60例患者的胃癌组织及对应癌旁组织(距肿瘤边缘>2 cm)标本。将胃癌细胞MGC803分为miR-494组和对照组。采用PCR检测胃癌组织及体外培养细胞中的miR-494表达水平。在MGC803细胞中过表达miR-494,采用MTT法检测细胞增殖,流式细胞术检测细胞周期及细胞凋亡。PCR及Western blotting检测miR-494潜在靶点Cyclin D1的表达变化。结果癌旁组织miR-494相对表达量较胃癌组织高(P<0.05)。不同肿瘤直径、TNM分期miR-494相对表达量比较,差异有统计学意义(P<0.05)。对照组MGC803细胞miR-494相对表达量较miR-494组低(P<0.05)。miR-494组OD值较对照组低(P<0.05)。对照组CyclinD1 mRNA和蛋白相对表达量较miR-494组高(P<0.05)。miR-494与CyclinD1免疫组织化学评分呈负相关(r=-0.469,P<0.05)。结论胃癌组织中miR-494表达水平降低,过表达miR-494能通过下调Cyclin D1的表达发挥抑制胃癌细胞增殖和细胞周期进展的作用。

The Application of the Complementary and Alternative Therapies in Relieving Insomnia for Cancer Patients

Objective:To observe the curative effect of the complementary and alternative therapies in relieving insomnia for cancer patients.Method:According to the principle of randomization,with meeting the inclusion criteria,the 60 patients who were diagnosed as insomnia caused by liver qi stagnation were randomly divided into the control group and the intervention group.The intervention group(30 individuals treated with mini-needle therapy combined with TCM five elements music),the control group(30 individuals who were treated with single mini-needle therapy),the body buried needle 24 hours/time,5 times for a course of treatment,interval of 2 days between 2 courses,a total of 8 needles embedded.Pittsburgh sleep quality index(PSQI)scores of 2 groups were analyzed using SPSS19.0 statistical software.Results:The total effective rate was 86.1%in the intervention group,and 75.9%in the control group,the difference was statistically significant between 2 groups(P<0.05).The comparison of the PSQI score between the 2 groups propost treatment showed that there were statistically significant differences(P<0.05).The reduction rate of PSQI in the intervention group was 31.7%,indicating that 31.7%was effective,while 23.1%in the control group was ineffective.Conclusion:The mini-needle therapy combined with TCM five elements music could relieve insomnia caused by qi stagnation of liver in patients with advanced cancer.

A Parameter-Detection Algorithm for Moving Ships

In traffic-monitoring systems, numerous vision-based approaches have been used to detect vehicle parameters. However, few of these approaches have been used in waterway transport because of the complexity created by factors such as rippling water and lack of calibration object. In this paper, we present an approach to detecting the parameters of a moving ship in an inland river. This approach involves interactive calibration without a calibration reference. We detect a moving ship using an optimized visual foreground detection algorithm that eliminates false detection in dynamic water scenarios, and we detect ship length, width, speed, and flow. We trialed our parameter-detection technique in the Beijing-Hangzhou Grand Canal and found that detection accuracy was greater than 90% for all parameters.

Thermodynamic property of sandwich cylindrical shell structure with metallic wire mesh:Numerical modeling and experimental analysis

As a new addition to lightweight composite structures,the sandwich cylindrical shell with a metallic wire mesh core has emerged as a promising solution for thermodynamic performance analysis at elevated temperatures.The intricate interwoven cellular formations within the metallic wire mesh pose difficulties for thermo-mechanical modeling and property evaluation.First,the constitutive models employed to characterize hysteresis phenomena were presented,comprising isotropic elasticity,Bergstrom-Boyce model,Ogden hyper-elasticity,and parameter identification through mechanical examinations at varying temperatures.Second,the finite element modeling of cylindrical shell structures was determined for modal and steady-state dynamic analyses.Third,the experimental procedures were carried out,including the preparation of the sandwich cylindrical shell and the dynamic testing platform.The first-order natural frequency of the cylindrical shell structure is close to the resonance frequency of the dynamic test results,with a maximum error of 6.5%,demonstrating the accuracy of the simulation model.When compared to the solid-core cylindrical shell,the average insertion loss of the sandwich cylindrical shell structure within the frequency range of 10–1000 Hz at room temperature is up to 11.09 dB.Furthermore,at elevated temperatures,the average insertion loss of the sandwich cylindrical shell decreases but fluctuates as the temperature changes.

Convergence and Stability of an Explicit Method for Autonomous Time-Changed Stochastic Differential Equations with Super-Linear Coefficients

In this paper,numerical methods for the time-changed stochastic differential equations of the form dY(t)=a(Y(t))dt+b(Y(t))dE(t)+s(Y(t))dB(E(t))are investigated,where all the coefficients a(·),b(·)and s(·)are allowed to contain some super-linearly growing terms.An explicit method is proposed by using the idea of truncating terms that grow too fast.Strong convergence in the finite time of the proposed method is proved and the convergence rate is obtained.The proposed method is also proved to be able to reproduce the asymptotic stability of the underlying equation in the almost sure sense.Simulations are provided to demonstrate the theoretical results.

Optimization of variables for maximizing efficacy and efficiency in aerial spray application to cotton using unmanned aerial systems

Aerial spraying can support efficient defoliation without crop contact.With the recent introduction to unmanned aerial system(UAS)for aerial spraying in China,there is a need to determine the optimum application variables to achieve high efficacy and efficiency with low costs.The present research involved field studies across two annual cotton production seasons in North Xinjiang,China.Four factors,including volume rate(A),tank mix including spray adjuvants(B),flight altitude(C),flight speed(D)and three levels of L9(3^(4))orthogonal arrays were carried out to optimize the application parameters for three types of UASs.These included different numbers of rotors as follows:four-rotors,six-rotors and eight-rotors.Spray coverage,distribution uniformity(coefficient of variation(CV)of droplet coverage),rates of cotton defoliation and boll opening,application efficiency and cost were measured and assessed.Results showed that:(1)the rates of defoliation and boll opening by aerial cotton defoliant application could meet the requirement of cotton mechanized harvesting;(2)the optimal scenario for the three UASs was A_(3)B_(2)C_(1)D_(3),Volume rate(A3):48 L/hm^(2);Tank mix and concentration(B_(2)):(Tuotulong 225+Sujie 750+Ethephon 2250)mL/hm^(2),Flight altitude(C_(1)):1.5 m,and Flight speeds(D_(3))for unmanned helicopters with four-rotors,six-rotors and eight-rotors were 3.12 m/s,2.51 m/s and 3.76 m/s,respectively.These results can provide guidance for cotton defoliant aerial spraying in China using UAS.

Hot-cracking susceptibility and shear fracture behavior of dissimilar Ti6Al4V/AA6060 alloys in pulsed Nd:YAG laser welding

Laser welding of dissimilar titanium/aluminum alloys has been employed at an increasing rate,particularly in the aerospace industry,owing to its advantages in terms of current design flexibility and fuel/cost savings.The major problem with dissimilar Ti/Al welds arises from the difference in the thermal expansion and contraction of the two metals,which leads to hot-cracking susceptibility and the mitigation of the mechanical property after welding.In the present study,pulsed Nd:YAG laser welding of Ti6 Al4 V and AA6060 has been addressed.Hot-cracking susceptibility in the heat affected zone and the shear fracture behavior of the lap joints were investigated through microstructural characterization and mechanical tests.The results indicate that the hot cracking tendency can be reduced by increasing the pulse peak power(7.5–8.5 kW)and the laser point diameter(0.8–1.0 mm)with specific pulse duration and overlap.An alternative control strategy for less hot cracks in the Ti/Al lap joint can be to increase the weld width and decrease the cooling rate during solidification.The shear fracture of the Ti/Al lap joint is likely to occur along the lower side path of the weld interface with decreasing weld surface collapsed amount and increasing aluminum base metal melt depth.

DP钢板应变路径多步演变下的弹塑性力学行为

针对DP高强双相钢板在复杂载荷作用下的弹塑性力学特征,提出利用三步拉伸力学实验,对比分析单轴循环加载和非等轴加载下材料的各向异性硬化、永久软化和弹性模量衰减特性等力学行为,揭示应变路径多步演变下的弹塑性力学特性。研究结果表明:材料再加载初期的瞬态行为与应变路径有关,在初期瞬态阶段显示出明显的各向异性,且再加载角度、预应变量以及马氏体含量的增加都会加剧两种DP钢过渡期后的应力软化行为。同时对不同加载下DP钢弹性模量的演化进行了对比,发现弹性模量的衰减程度也随着再加载角度,预应变量和马氏体含量的增加而增加,弹性模量衰减程度在多步非等轴加载比单轴循环载荷作用下表现更明显。

纺锤状纤维结构的设计及其PM_(2.5)过滤性能研究

城市雾霾,特别是其中的PM_(2.5)颗粒(当量直径≤2.5μm),因其自身危害及其携带的病原体对公共健康具有严重威胁而被人们广泛关注.静电纺丝纳米纤维作为空气过滤膜实现PM_(2.5)高效捕获是国内外研究热点,但现有的纺丝滤膜仍存在无法兼顾高过滤效率和低空气阻力的问题.根据蛛丝微观结构特点,采用静电纺丝技术,通过在纺丝纤维内部引入不同形貌黏土矿物及其微球前驱体的策略,可实现复合纤维及其滤膜材料的多级结构构筑和微观形貌调控,成功设计具有纺锤状埃洛石微球节点的仿生纳米纤维滤膜材料.其纤维表面富含亲水基团及活性位点,粗糙的表面形貌具有高表面能及PM_(2.5)颗粒的强捕获性.对比纯纺丝滤膜(62.59μm),纺锤状节点滤膜具有蓬松的纤维膜层间架构(74.17μm)及窄尺寸的表面孔隙,可实现稳定高效的PM_(2.5)过滤效率(>85.0%)及持续低压差阻力(~39 Pa).本文探索了纳米纤维的官能化、多层次结构构建和微观形貌调控对纺丝滤膜过滤性能的影响及其过滤机制理论,为其他新型高性能高分子纳米纤维复合材料的设计和开发提供了借鉴.

High-yield synthesis of a novel water-soluble macrocycle for selective recognition of naphthalene

A novel good water-soluble macrocycle containing two pyridinium moieties was synthesized in high yield.It could form 1:1 complexes with neutral guests containing naphthalene or phenyl units in water.The water-soluble macrocycle can selectively encapsulate naphthalene to form a 1:1 complex over a variety of polycyclic aromatic hydrocarbons.

Development of droplet characteristics prediction models for air induction nozzles based on wind tunnel tests

Nozzle flowrate and spray pressure are two of the most important factors influencing on droplet characteristics.With the aim to develop prediction models for air-induction nozzles(AINs),a series of Billericay Farm Services(BFS)AINs with different orifice diameters in combination with tap water were tested.0.2 MPa,0.3 MPa,0.4 MPa,0.5 MPa,0.6 MPa and 0.7 MPa of spray pressures and 2 m/s,3 m/s,4 m/s and 5 m/s of air speeds were setup.Based on the wind tunnel tests data,prediction models with input variables of nozzle flowrate and spray pressure and output variables of D_(v0.1),D_(v0.5),D_(v0.9),%<150μm(proportion of spray volume contained in droplets with diameter below 150μm),relative span(RS)and coefficient of variation(CV)of D_(v0.5) were developed.The developed models were validated based on wind tunnel experimental data.Results showed that:for D_(v0.1),D_(v0.5),D_(v0.9) and%<150μm,R^(2) were equal to 0.768,0.823,0.868 and 0.811,indicating that the predictive ability for these four parameters is strong.For RS and CV,R^(2) were equal to 0.100 and 0.113,respectively,indicating that the predictive ability for these two parameters is poor.The models developed in the present study are helpful for facilitating the use of AIN in agricultural spray application.

Optimization of aviation adjuvants based on wettability analysis for insecticide application on maize using UAV

Adjuvants can increase the control efficacy of diseases and insect pests by changing the physico-chemical properties of pesticides.Most of the aviation spray adjuvants are versions of ground adjuvants.Maize insecticide sprays with unmanned aerial vehicles(UAV),have problems such as relatively low droplet deposition rate and poor wettability.Hence,wettability research and optimization tests for aviation spray adjuvants are needed.The present study screened 12 spray adjuvants using physico-chemical property experiments.The adjuvants were applied to improve the droplet deposition and control efficacy in maize borers controlling by UAV.The selected spray adjuvants were Po2(a hyperbranched polymer adjuvant)and VO3(a vegetable oil adjuvant).Results showed that,(1)When Po2 was added in water-dispersible granules(WGs)at volume rate of 12 L/hm2,the dynamic surface tension(DST)of WGs was decreased by 37.41%,and the maize leaves were covered by droplets 100%,the droplet deposition was increased by 104%and maize borer control was increased by 46%;(2)VO3 decreased the surface tension of ultra-low-volume(ULV)formulation by 12.02%and the maize leaves were covered by droplets 100%.The effect of VO3 on improving the droplet deposition and control efficacy at 12 L/hm2 with ULV was not significant.Thus,the addition of aviation spray adjuvant to improve the wettability of WGs significantly improved the droplet deposition and control efficacy but it had no significant effect on the ULV formulation.

Preparation of three-dimensional nanoporous copper foil with high specific surface area

The porous copper foil material has the advantages of ultralight and ultra-thin,and can prevent dangers such as thermal runaway and battery fire,which could be regarded as a prospective material for lithium battery cathodes.Here,a porous copper foil with a three-dimensional(3D)pore structure was synthesized by alkali and acid etching.