The deformation behavior and formability of gradient nano-grained(GNG) AISI 304 stainless steel in uniaxial and biaxial states were investigated by means of tensile test and small punch test(SPT). The GNG top laye...The deformation behavior and formability of gradient nano-grained(GNG) AISI 304 stainless steel in uniaxial and biaxial states were investigated by means of tensile test and small punch test(SPT). The GNG top layer was fabricated on coarse grains(CG) AISI 304 by ultrasonic impact treatment. The results showed that the CG substrate could effectively suppress the strain localization of NC in GNG layer, and an approximate linear relationship existed between the thickness of substrate(h) and uniform true strain before necking(ε_(unif)). Grain growth of NC was observed at the stress state with high Stress triaxiality T, which led to better ductility of GNG/CG 304 in SPT, as well as similar true strain after the onset of necking(ε_(neck)) compared with coarse 304 in tensile test. Ei-values of GNG/CG 304 with different structures were nearly the same at different punch speeds, and good formability of GNG/CG 304 was demonstrated. However, punch speed and microstructure needed to be optimized to avoid much lost of membrane strain region in biaxial stress state.展开更多
Influence of heat treatment on mechanical properties and tribological behaviors of Ti and B modified wrought aluminum bronze were studied. The results show that different strength and plasticity combination of the all...Influence of heat treatment on mechanical properties and tribological behaviors of Ti and B modified wrought aluminum bronze were studied. The results show that different strength and plasticity combination of the alloy after solution treatment can be obtained by adjusting the ageing temperature. When aged at 450?℃, the tensile strength σ b, yield strength σ 0.2 , elongation δ and hardness of the alloy are 1?050?MPa, 780?MPa, 4.5%, HB282, respectively. When aged at 650?℃, those of the alloy are 905?MPa, 600?MPa, 12%, HB232, respectively. Under boundary lubrication condition with pressure above 22.2?MPa, alloy with low temperature ageing has the best wear property. However, under the condition involving impact or shock loading, alloy with high temperature ageing is preferable. If the load is not heavy, the alloy under extrusion state is favorable for wear resisting parts.展开更多
To improve the low thermal conductivities and poor wear resistances of TC4(Ti-6Al-4V)alloy,the most widely used titanium alloy,the surface of TC4 alloys is modified by electroplating deposition of Ni and Cu layers,and...To improve the low thermal conductivities and poor wear resistances of TC4(Ti-6Al-4V)alloy,the most widely used titanium alloy,the surface of TC4 alloys is modified by electroplating deposition of Ni and Cu layers,and then heat-treated to increase the diffusivity at the interface.In this paper,the corrosion behavior of Cu/Ni coatings on TC4 alloy at different heat treatment processes was investigated in 3.5 wt%Na Cl by the electrochemical analysis,and the microstructure and composition of corrosion products was carried out to reveal the corrosion resistance mechanism of Cu/Ni coatings.It was found that the corrosion resistance was significantly influenced by heat treatment temperature.With the increasing diffusion treatment temperature from 500 to 700℃,the corrosion potential positively shifted from-330.87 to-201.14 m V,and the corrosion current density decreased from 4.02×10^-3 to 0.514×10^-3 m A/cm^2.However,when heat treatment temperature increased to 800℃,the corrosion potential negatively shifted to-207.21 m V,and the current density increased to 1.62×10^-3 m A/cm^2.The diffusion behavior of Ti,Ni and Cu elements occurred and small amounts of Ni and Ti elements appeared on the specimen surface under different heat treatment temperature.Especially heattreated at 700℃,the smaller pore size,dense Cu2O film,and highly stable Ti O and Ni O oxide layer were formed,which dramatically enhanced the corrosion resistance of Cu/Ni coatings.Finally,a novel model of corrosion resistance was proposed based on the analysis mentioned above.展开更多
The superelastic behaviors of different isothermal treated Cu-13.SAl-4.ONi (mass fraction) single crystals were studied by applying tensile stress along <001> of the d phase. The different isothermal specimens h...The superelastic behaviors of different isothermal treated Cu-13.SAl-4.ONi (mass fraction) single crystals were studied by applying tensile stress along <001> of the d phase. The different isothermal specimens have different superelastic behavior due to the change of the ratio of stress-induced r1 and β1. The superelasticity of r1 phase tends to that of g; phase with cycling. Typical stabilization of stress-induced martensite above Ap results in residual deformation. Due to the reverse transformation of 7I, there is a deviation of pseudo-yield stress from linear relation with temperature at relatively low stress.展开更多
Two micron SiC particles with angular and spherical shape and the sub-micron Al2O3 particles with spherical shape were introduced to reinforce 6061 aluminium by squeeze casting technology.Microstructures and effect of...Two micron SiC particles with angular and spherical shape and the sub-micron Al2O3 particles with spherical shape were introduced to reinforce 6061 aluminium by squeeze casting technology.Microstructures and effect of thermal-cooling cycle treatment(TCCT) on the thermal expansion behaviors of three composites were investigated.The results show that the composites are free of porosity and SiC/Al2O3 particles are distributed uniformly.Inflections at about 300 °C are observed in coefficient of thermal expansion(CTE) versus temperature curves of two SiCp/Al composites,and this characteristic is not affected by TCCT.The TCCT has significant effect on thermal expansion behavior of SiCp/Al composites and CTE of them after 3 cycles is lower than that of 1 or 5 cycles.However,no inflection is observed in Al2O3p/Al composite,while TCCT has effect on CTE of Al2O3p/Al composite.These results should be due to different relaxation behavior of internal stress in three composites.展开更多
The solidification-precipitation behavior of Al-Mg-Si multicomponent alloys has long been an absorbing topic. Experiments were carried out to analyze the precipitation behaviors of Al-Mg-Si alloys under different heat...The solidification-precipitation behavior of Al-Mg-Si multicomponent alloys has long been an absorbing topic. Experiments were carried out to analyze the precipitation behaviors of Al-Mg-Si alloys under different heat treatments. All specimens were homogenized at 570 °C for 8 h, and then solution treated at 540 °C for 55 min. Subsequently, the specimens were age treated for different times at temperatures of 100 °C, 150 °C and 180 °C, respectively. The experimental results show that the occurrence of dispersed free zones(DFZ) is caused by the uneven distribution of dispersed phase. During the aging process, pre-β″ phases form at the initial stage and an aging temperature of 100 °C is too low to complete the transformation of pre-β″ to β″. At 150 °C, the precipitation sequence is concluded as SSSS-pre-β″-pre-β″+β″-β″-β′-β. Moreover, changes in sizes and densities of the pre-β″, β″and β′ phases during the aging process has an important influence on the evolution of microhardness and electrical resistivity. The microhardness peak value of 150 °C is similar to that of 180 °C, which is ~141 HV. While, at 100 °C, the microhardness increases slowly, and the attainable value is 127 HV up to 19 days. When the aging temperature is 100 °C, the electrical resistivity has the highest average value. When the aging temperature exceeds 100 °C, with the occurrence and growth of β″and β′, the resistivity has a distinct decrease with prolonged aging time.展开更多
The influence of two novel aging treatments, T6I6 (130 ℃, 80 min + 65 ℃, 240 h+130 ℃, 18 h) and high-temperature pre-precipitation(HTPP) aging (445 ℃, 30 min+120 ℃, 24 h) on the tensile properties, intergranular ...The influence of two novel aging treatments, T6I6 (130 ℃, 80 min + 65 ℃, 240 h+130 ℃, 18 h) and high-temperature pre-precipitation(HTPP) aging (445 ℃, 30 min+120 ℃, 24 h) on the tensile properties, intergranular corrosion, exfoliation corrosion behaviors and microstructures of 7075 Al alloy was studied, which were compared with the T6, T73 and RRA treatments. Fine η′ precipitate with high density was obtained in the alloy with the T6 and RRA treatments. The η′ precipitate density in the HTPP aged alloy is decreased due to the formation of coarse particles during the pre-precipitation process at high temperature of 445 ℃. The 7075-T6I6 alloy possesses higher precipitate density and whole precipitate volume fraction within the grain than the 7075-T73 alloy, and its whole precipitate volume fraction is even greater than that of the 7075-T6 alloy. Compared with T6 treatment, the RRA, T73, T6I6 and HTPP aging treatments cause the discontinuous distribution of the η precipitates at the grain boundary, which decreases the intergranular corrosion and exfoliation corrosion susceptibility of the alloy. Meanwhile, the T6I6 and RRA treatments can keep the high strength of the 7075 Al alloy, but the studied HTPP aging and T73 treatments lower its strength.展开更多
The effects of two kinds of heat treatments T4(solution treatment) and T6(aging treatment) on the corrosion behaviors of Mg-3Zn magnesium alloy were studied by electrochemical measurements and scanning electron micros...The effects of two kinds of heat treatments T4(solution treatment) and T6(aging treatment) on the corrosion behaviors of Mg-3Zn magnesium alloy were studied by electrochemical measurements and scanning electron microscopy(SEM) .It is found that zinc element enriches along grain boundaries to exhibit a network microstructure for both T4-and T6-treated alloy.For T6 treatment,larger MgZn particles form mainly on grain boundary and fine MgZn particles precipitate on matrix.Compared with cast alloy,T4 treatment could decrease the amounts of MgZn particles,and decrease the zinc content of zinc-rich net-segregation.Electrochemical measurements show that T4 treatment increases the corrosion resistance while T6 treatment decreases the corrosion resistance of Mn-3Zn alloy.展开更多
Deficiency in executive functioning is a core symptom of attention deficit hyperactivity disorder (ADHD). The brain part responsible for executive functions is the prefrontal cortex (PFC). Although drug-based interven...Deficiency in executive functioning is a core symptom of attention deficit hyperactivity disorder (ADHD). The brain part responsible for executive functions is the prefrontal cortex (PFC). Although drug-based interventions can improve PFC activity, reports on PFC activity being improved by behavioral treatment are lacking. We evaluated whether a summer treatment program (STP) administering comprehensive behavioral treatment would increase PFC activity in children with ADHD. We examined behavioral and neural changes in 20 children before and after the STP, conducted over a 2-week period. We asked the parents/guardians to complete the Swanson, Nolan, and Pelham IV scale to assess severity of ADHD. The main task evaluating executive control was the reverse Stroop task. To examine changes in physiological indices, we used near-infrared spectroscopy to measure changes in PFC activity. Subjective assessments by parents/guardians indicated that ADHD symptoms improved significantly. There was also significant improvement in the number of correct responses and interference rates in the reverse Stroop task. Furthermore, post-intervention PFC activity was significantly higher. These results suggest that the STP improved inhibitory control in executive function, which is considered as a key symptom of ADHD. The increase in PFC activity further suggests that the STP improves cognition through neural function.展开更多
Objective: To explore the effects of the behavioral treatment combined with psychological counseling on female coital disorder in China. Methods: One hundred and sixteen female patients with coital disorder were divid...Objective: To explore the effects of the behavioral treatment combined with psychological counseling on female coital disorder in China. Methods: One hundred and sixteen female patients with coital disorder were divided into sexual behavior training combined with psychological counseling group (group A, 59 cases) and psychological counseling alone group (group B, 57 cases). Results: Forty-five cases cured (76.27%), eight eases improved (13.56%), and six cases invalid (10.17%), the general rate of effectiveness being 89.83% in group A while eleven cases cured (19.30%), twenty-one cases improved (36.84%), and twenty-five cases invalid (43.86%), the general rate of effectiveness being 56.14% in group B. The curative effect of group A was better than group B (P Conclusions: The behavioral treatment combined with psychological counseling is significantly effective in treating female coital disorder than psychological counseling alone and its long term follow-up results show that most of patients were satisfied with their sex life. However, the response of behavioral treatment of some patients who had bad experience on sexual things in the progress of their growing up or had long course of disease were not so good which deserves our special attention in the future study.展开更多
Children with attention deficit and hyper activity disorder have various problems such as low academic performance, social and communication problems, anxiety, depression, aggression, conduct disorder and delinquency,...Children with attention deficit and hyper activity disorder have various problems such as low academic performance, social and communication problems, anxiety, depression, aggression, conduct disorder and delinquency, and also when they become adults, they have problems in social relationships that these problems can increase or decrease in dealing with family. Hence, this study was performed in order to examine the impact of family-based behavioral treatment compared with Barkley behavior therapy in reducing symptoms of children with attention deficit disorder—ADHD. To meet the aim, 20 of children with age range of 7 to 12 years old with attention deficit disorder—hyperactivity were selected in both experimental and control groups, and exposed to the treatment of behavioral family therapy groups and changes in behavior Barkley. Before and after the treatment, they were evaluated according to the scale of the Conner’s Parent Rating Scale-Revised Short Form (CPRS-R: S). Results of multivariate analysis of covariance indicated that there were significant differences between the experimental group who had received family-based behavioral treatments based on changes in behavior Barkley and a control group who had received drug treatment in variables, including conduct problems, learning problems, psychosomatic symptoms, and signs of impulsive hyperactivity, anxiety and hyperactivity (p < 0.01). These results could be guidance for counsel or sand therapists for children with attention deficit disorder—ADHD.展开更多
The corrosion behaviors of a basic type of RE-containing magnesium alloy Mg-15Y processed by different heat treatment methods were studied in 3.5% NaC1 solution at room temperature. The amount of Mg24Y5 phase decrease...The corrosion behaviors of a basic type of RE-containing magnesium alloy Mg-15Y processed by different heat treatment methods were studied in 3.5% NaC1 solution at room temperature. The amount of Mg24Y5 phase decreased with the extending of homogenization treatment. The time for achieving dissolving equilibrium of homogenization treatment at 525, 535, and 545 ℃ was 24, 20, and 8 h, respectively. The corrosion behavior of Mg-15Y alloy was studied using immersion, hydrogen evolution and electrochemical tests. The experimental results revealed that the heat treatment improved the corrosion resistance, and the corrosion resistance became better with increasing the heat treatment time. The corrosion mode of the alloy after heat treatment was microgalvanic corrosion consisting of the cathodic Mg24Y5 phase and anodic α-Mg matrix, and Mg-15Y exhibited favorable uniform corrosion mode in NaC1 solution. The volume and increasing tendency of the homogenization treatment samples were both more than those of the as-cast sample.展开更多
Silicon carbide ceramics were prepared with SiC powder treated by the fluidized bed opposed jet mill as raw materials, and the effects of the ultra-fine treatment mechanism on the compaction and sintering behavior of ...Silicon carbide ceramics were prepared with SiC powder treated by the fluidized bed opposed jet mill as raw materials, and the effects of the ultra-fine treatment mechanism on the compaction and sintering behavior of SiC ceramics were investigated. The results showed that the compacts had higher density and microstructure homogeneity when the sintering temperature of the compact was decreased; and that the surface microstructure, densification and mechanical properties of the sintered body could be ameliorated obviously.展开更多
The polymorphic behavior of syndiotactic polypropylene (s-PP) crystallized from the melt under different conditions was investigated by means of WAXD and DSC. The isothermal melt crystallization of s-PP proceeded in f...The polymorphic behavior of syndiotactic polypropylene (s-PP) crystallized from the melt under different conditions was investigated by means of WAXD and DSC. The isothermal melt crystallization of s-PP proceeded in form I at tc≥ 110℃ and in form Ⅱ at tc≤110 ℃ s-PP crystallized nonisothermally from the melt was the mixture of forms and . With increasing the cooling rate (a), the content of form increased, and the content of form decreased. On heating, at 10 K/min, of quenched s-PP, it crystallized in form at t≤70 , continuing heating resulted in form form transition, which was an endothermal process.展开更多
In Uganda, there is still insufficient comprehension of malaria as a lethal disease especially in rural areas despite universal bed-net distribution coverage and effective anti-malarial treatment. <strong>Aim:&l...In Uganda, there is still insufficient comprehension of malaria as a lethal disease especially in rural areas despite universal bed-net distribution coverage and effective anti-malarial treatment. <strong>Aim:</strong> To get evidence-based knowledge to establish the contribution of an individuals’ knowledge from various health communications that could increase their active involvement in health care especially seeking timely appropriate treatment for malaria or suspected malaria. <strong>Method:</strong> A cross-sectional survey using a correlational design was employed on a clustered sample of 380 rural households in 05 sub-counties of Kanungu district. Data were corrected between October 2016-January 2017 using researcher-administered questionnaires, key-informant interviews and focus group discussions. Correlation analysis was done. <strong>Result:</strong> There is a significant positive relationship between knowledge of health communications and treatment-seeking behavior (r = 0.312;<em>p</em> ≤ 0.01). <strong>Conclusion:</strong> Exposure to consistent Behavioral Change Communications messages influences treatment-seeking behaviour. Thus, in malaria-prone communities, it appears that other factors including sufficient targeted persuasive health communication are lacking in influencing personal orientations towards treatment-seeking behaviour. Therefore, proper Health Communications management supplements efforts from other disciplines and players, against malaria in Uganda.展开更多
The aim of the study was to evaluate the behavioral signs of diabetic rats after treatment by Artemisia herba-alba (AHA) and insulin. Method: Based on the induction of diabetes in wistar rats by intraperitoneal (I/P) ...The aim of the study was to evaluate the behavioral signs of diabetic rats after treatment by Artemisia herba-alba (AHA) and insulin. Method: Based on the induction of diabetes in wistar rats by intraperitoneal (I/P) injection of 60 mg/kg streptozotocin (STZ), then treated by AHA as 20 mg (I/P) and insulin subcutaneously (S/C). The samples of rats were: 1) Diabetic control, 2) Injected with insulin, 3) Injected with AHA, 4) Non diabetic rats, which were fostered for 21 day;then weighted and the behavioral tests were conducted. Results: The board hole tests (BHT) showed that: the induced diabetes reduced the cognition of the rats in view of Latency of the First Head Dipping (LFHD) in seconds, number of head dipping (NHD) and duration of head dipping (DHD) by 49.3%, while it’s improved in AHA and insulin treated rats by 52% and 69% in average respectively. The exploratory activity reduced in diabetic rats by 36%, while AHA and Insulin treated rats increased by 53% and 72% respectively. The rearing test showed an increase of anxiety among diabetic in form of duration of rearing, number of rearing and time spend in center by 51.7% in average respectively, while the anxiety reduced after treatment by AHA and insulin by 39% and 47.3% in average respectively. Also the diabetes increased the depression state by 106%, while the treatment by AHA and insulin reduced the depression state by 77% and 88% respectively. And VPT showed that: motor impairment occurred in diabetic cases and improved after AHA and insulin treatment.展开更多
Background: Even though domestic violence is a major problem, only a few studies have examined the long term sustainability of treatment for men who voluntarily seek help to stop their violent behavior towards intimat...Background: Even though domestic violence is a major problem, only a few studies have examined the long term sustainability of treatment for men who voluntarily seek help to stop their violent behavior towards intimate partners. Women are exposed to a much greater degree of serious violence and sexual abuse compared to men. Objective: The aim of this study was to identify which elements of the treatment program batterers found most useful four to seven years after program completion. Design: The participants consisted of a sample of men who had gone through anger management therapy four to seven years previously. Data on violence were collected through self-report before and four to seven years after treatment, using a modified version of the Conflict Tactics Scales. Results: The decrease in physical violence was statistically significant: t (36) = 8.43, p < 0.001 with a large effect size (eta squared = 0.66). Psychological violence also decreased significantly: t (36) = 9.21, p < 0.001 with a large effect size (eta squared = 0.7). The results indicate that the most important anger management techniques were extensively applied in former patients of the anger management treatment program. In total, about two out of three patients still used the techniques after ending treatment four to seven years earlier.展开更多
An aluminum alloy (6061) matrix composite reinforced with 35% (vol.) Al 2O 3 particles was fabricated by squeeze casting method. The Al 2O 3 particles were spherical. The microyield behavior of the composite and t...An aluminum alloy (6061) matrix composite reinforced with 35% (vol.) Al 2O 3 particles was fabricated by squeeze casting method. The Al 2O 3 particles were spherical. The microyield behavior of the composite and the effect of different thermal cycling treatment on the microyield behaviors of the composite were studied. Based on TEM and HREM observation of microstructure, the mechanism of microyield behavior in the Al 2O 3p/6061 composite was analyzed. The results indicate that the microyield behavior of the Al 2O 3p/6061 composite can be described by Brown Lukens theory, which was used satisfactorily for aluminum alloys and other light alloys, and is affected greatly by the different thermal cycling treatment. The more the cycles of thermal cycling treatment, the higher to microyield strength at small strains. Thermal cycling treatment affects mainly the thermal mismatch stress and the density of movable dislocations in the matrix.展开更多
Background: Late diagnosis of Human Immunodeficiency Virus (HIV) infection and delayed commencement of antiretroviral therapy (ART) in sub-Saharan Africa is known to contribute to high morbidity and mortality. It is t...Background: Late diagnosis of Human Immunodeficiency Virus (HIV) infection and delayed commencement of antiretroviral therapy (ART) in sub-Saharan Africa is known to contribute to high morbidity and mortality. It is therefore, prudent to develop innovative approaches to ensure early HIV diagnosis because patients with low immunity will usually develop opportunistic infections and seek some remedial action. A treatment and health care seeking behavior survey was carried out in semi-urban communities in Malaba and Busia in Kenya and Uganda to evaluate the treatment and healthcare seeking behavior among patients visiting randomly selected drugstores. Methodology: Random sampling was applied and questionnaires were used to collect information from 165 interviewees who visited drugstores seeking health information, treatment and other health related services. Results: The results indicated that among this group of people, 67% visited drugstores before any other health facility. 72.2% sought treatment for various illnesses and services ranging from headaches, body fever, gastro-intestinal disturbances, family planning pills, sexually transmitted infections and chronic medications. Among the patients interviewed, there were a number of factors that affected treatment choice. These included the distance to the facility as well as the absence of a consultation fee or fee for service. Conclusion: With proper support, drugstores can play a major role in the implementation of health interventions that seek to promote early diagnosis and treatment as well as play a pivotal role in educating the population on disease prevention and management. In Sub-Saharan Africa, drugstores can play a major role in HIV and AIDS interventions where most patients seek medical intervention for opportunistic infection.展开更多
An experimental study has been carried out to investigate the influence of heat treatment at 300 ℃,450 ℃,550 ℃,650 ℃ and 800 ℃ on the microstructure and sliding wear behavior of Fe Al/WC intermetallic composite c...An experimental study has been carried out to investigate the influence of heat treatment at 300 ℃,450 ℃,550 ℃,650 ℃ and 800 ℃ on the microstructure and sliding wear behavior of Fe Al/WC intermetallic composite coatings produced by high velocity arc spraying (HVAS) and cored wires. The result shows, the main phases in both as sprayed and heat treated Fe Al/WC composite coatings are iron aluminide intermetallics (Fe 3Al+FeAl) and α as well as a little oxide (Al 2O 3) and carbides (WC, W 2C, Fe 2W 2C and Fe 6W 6C). After heat treated at 450-650 ℃, dispersion strengthening of Fe 2W 2C and Fe 6W 6C will lead to a rise in microhardness of the coatings. The microhardness is likely to be the most important factor which influences the sliding wear behavior of the coatings. Increasing the microhardness through heat treatment will improve the sliding wear resistance of the Fe Al/WC composite coatings.展开更多
基金Funded by the National National Natural Science Foundation of China(No.51505189)Open Project of Jiangsu Key Laboratory of Advanced Food Manufacturing Equipment&Technology(No.FM-2015-5)
文摘The deformation behavior and formability of gradient nano-grained(GNG) AISI 304 stainless steel in uniaxial and biaxial states were investigated by means of tensile test and small punch test(SPT). The GNG top layer was fabricated on coarse grains(CG) AISI 304 by ultrasonic impact treatment. The results showed that the CG substrate could effectively suppress the strain localization of NC in GNG layer, and an approximate linear relationship existed between the thickness of substrate(h) and uniform true strain before necking(ε_(unif)). Grain growth of NC was observed at the stress state with high Stress triaxiality T, which led to better ductility of GNG/CG 304 in SPT, as well as similar true strain after the onset of necking(ε_(neck)) compared with coarse 304 in tensile test. Ei-values of GNG/CG 304 with different structures were nearly the same at different punch speeds, and good formability of GNG/CG 304 was demonstrated. However, punch speed and microstructure needed to be optimized to avoid much lost of membrane strain region in biaxial stress state.
文摘Influence of heat treatment on mechanical properties and tribological behaviors of Ti and B modified wrought aluminum bronze were studied. The results show that different strength and plasticity combination of the alloy after solution treatment can be obtained by adjusting the ageing temperature. When aged at 450?℃, the tensile strength σ b, yield strength σ 0.2 , elongation δ and hardness of the alloy are 1?050?MPa, 780?MPa, 4.5%, HB282, respectively. When aged at 650?℃, those of the alloy are 905?MPa, 600?MPa, 12%, HB232, respectively. Under boundary lubrication condition with pressure above 22.2?MPa, alloy with low temperature ageing has the best wear property. However, under the condition involving impact or shock loading, alloy with high temperature ageing is preferable. If the load is not heavy, the alloy under extrusion state is favorable for wear resisting parts.
基金Funded by Key Projects of Shaanxi Natural Science Foundation(No.2019JZ-27)Shaanxi Natural Science Basic Research Program-Shaanxi Coal(No.2019JLM-47)Fundamental Research Funds for the Central Universities CHD(No.300102319304).
文摘To improve the low thermal conductivities and poor wear resistances of TC4(Ti-6Al-4V)alloy,the most widely used titanium alloy,the surface of TC4 alloys is modified by electroplating deposition of Ni and Cu layers,and then heat-treated to increase the diffusivity at the interface.In this paper,the corrosion behavior of Cu/Ni coatings on TC4 alloy at different heat treatment processes was investigated in 3.5 wt%Na Cl by the electrochemical analysis,and the microstructure and composition of corrosion products was carried out to reveal the corrosion resistance mechanism of Cu/Ni coatings.It was found that the corrosion resistance was significantly influenced by heat treatment temperature.With the increasing diffusion treatment temperature from 500 to 700℃,the corrosion potential positively shifted from-330.87 to-201.14 m V,and the corrosion current density decreased from 4.02×10^-3 to 0.514×10^-3 m A/cm^2.However,when heat treatment temperature increased to 800℃,the corrosion potential negatively shifted to-207.21 m V,and the current density increased to 1.62×10^-3 m A/cm^2.The diffusion behavior of Ti,Ni and Cu elements occurred and small amounts of Ni and Ti elements appeared on the specimen surface under different heat treatment temperature.Especially heattreated at 700℃,the smaller pore size,dense Cu2O film,and highly stable Ti O and Ni O oxide layer were formed,which dramatically enhanced the corrosion resistance of Cu/Ni coatings.Finally,a novel model of corrosion resistance was proposed based on the analysis mentioned above.
文摘The superelastic behaviors of different isothermal treated Cu-13.SAl-4.ONi (mass fraction) single crystals were studied by applying tensile stress along <001> of the d phase. The different isothermal specimens have different superelastic behavior due to the change of the ratio of stress-induced r1 and β1. The superelasticity of r1 phase tends to that of g; phase with cycling. Typical stabilization of stress-induced martensite above Ap results in residual deformation. Due to the reverse transformation of 7I, there is a deviation of pseudo-yield stress from linear relation with temperature at relatively low stress.
基金Project(20080430895) supported by China Postdoctoral Science FoundationProject(2008RFQXG045) supported by Special Fund of Technological Innovation of HarbinProject(HITQNJS.2009.021) supported by Development Program for Outstanding Young Teachers in Harbin Institute of Technology
文摘Two micron SiC particles with angular and spherical shape and the sub-micron Al2O3 particles with spherical shape were introduced to reinforce 6061 aluminium by squeeze casting technology.Microstructures and effect of thermal-cooling cycle treatment(TCCT) on the thermal expansion behaviors of three composites were investigated.The results show that the composites are free of porosity and SiC/Al2O3 particles are distributed uniformly.Inflections at about 300 °C are observed in coefficient of thermal expansion(CTE) versus temperature curves of two SiCp/Al composites,and this characteristic is not affected by TCCT.The TCCT has significant effect on thermal expansion behavior of SiCp/Al composites and CTE of them after 3 cycles is lower than that of 1 or 5 cycles.However,no inflection is observed in Al2O3p/Al composite,while TCCT has effect on CTE of Al2O3p/Al composite.These results should be due to different relaxation behavior of internal stress in three composites.
基金financially supported by the Natural Science Foundation of Shandong Province(ZR2016EMQ11)the Major Research and Development Program of Shandong Province(2017GGX20119),China
文摘The solidification-precipitation behavior of Al-Mg-Si multicomponent alloys has long been an absorbing topic. Experiments were carried out to analyze the precipitation behaviors of Al-Mg-Si alloys under different heat treatments. All specimens were homogenized at 570 °C for 8 h, and then solution treated at 540 °C for 55 min. Subsequently, the specimens were age treated for different times at temperatures of 100 °C, 150 °C and 180 °C, respectively. The experimental results show that the occurrence of dispersed free zones(DFZ) is caused by the uneven distribution of dispersed phase. During the aging process, pre-β″ phases form at the initial stage and an aging temperature of 100 °C is too low to complete the transformation of pre-β″ to β″. At 150 °C, the precipitation sequence is concluded as SSSS-pre-β″-pre-β″+β″-β″-β′-β. Moreover, changes in sizes and densities of the pre-β″, β″and β′ phases during the aging process has an important influence on the evolution of microhardness and electrical resistivity. The microhardness peak value of 150 °C is similar to that of 180 °C, which is ~141 HV. While, at 100 °C, the microhardness increases slowly, and the attainable value is 127 HV up to 19 days. When the aging temperature is 100 °C, the electrical resistivity has the highest average value. When the aging temperature exceeds 100 °C, with the occurrence and growth of β″and β′, the resistivity has a distinct decrease with prolonged aging time.
基金Project(2005CB623700) supported by the National Basic Research Program of China
文摘The influence of two novel aging treatments, T6I6 (130 ℃, 80 min + 65 ℃, 240 h+130 ℃, 18 h) and high-temperature pre-precipitation(HTPP) aging (445 ℃, 30 min+120 ℃, 24 h) on the tensile properties, intergranular corrosion, exfoliation corrosion behaviors and microstructures of 7075 Al alloy was studied, which were compared with the T6, T73 and RRA treatments. Fine η′ precipitate with high density was obtained in the alloy with the T6 and RRA treatments. The η′ precipitate density in the HTPP aged alloy is decreased due to the formation of coarse particles during the pre-precipitation process at high temperature of 445 ℃. The 7075-T6I6 alloy possesses higher precipitate density and whole precipitate volume fraction within the grain than the 7075-T73 alloy, and its whole precipitate volume fraction is even greater than that of the 7075-T6 alloy. Compared with T6 treatment, the RRA, T73, T6I6 and HTPP aging treatments cause the discontinuous distribution of the η precipitates at the grain boundary, which decreases the intergranular corrosion and exfoliation corrosion susceptibility of the alloy. Meanwhile, the T6I6 and RRA treatments can keep the high strength of the 7075 Al alloy, but the studied HTPP aging and T73 treatments lower its strength.
基金Project(2007CB613705)supported by the National Basic Research Program of China
文摘The effects of two kinds of heat treatments T4(solution treatment) and T6(aging treatment) on the corrosion behaviors of Mg-3Zn magnesium alloy were studied by electrochemical measurements and scanning electron microscopy(SEM) .It is found that zinc element enriches along grain boundaries to exhibit a network microstructure for both T4-and T6-treated alloy.For T6 treatment,larger MgZn particles form mainly on grain boundary and fine MgZn particles precipitate on matrix.Compared with cast alloy,T4 treatment could decrease the amounts of MgZn particles,and decrease the zinc content of zinc-rich net-segregation.Electrochemical measurements show that T4 treatment increases the corrosion resistance while T6 treatment decreases the corrosion resistance of Mn-3Zn alloy.
文摘Deficiency in executive functioning is a core symptom of attention deficit hyperactivity disorder (ADHD). The brain part responsible for executive functions is the prefrontal cortex (PFC). Although drug-based interventions can improve PFC activity, reports on PFC activity being improved by behavioral treatment are lacking. We evaluated whether a summer treatment program (STP) administering comprehensive behavioral treatment would increase PFC activity in children with ADHD. We examined behavioral and neural changes in 20 children before and after the STP, conducted over a 2-week period. We asked the parents/guardians to complete the Swanson, Nolan, and Pelham IV scale to assess severity of ADHD. The main task evaluating executive control was the reverse Stroop task. To examine changes in physiological indices, we used near-infrared spectroscopy to measure changes in PFC activity. Subjective assessments by parents/guardians indicated that ADHD symptoms improved significantly. There was also significant improvement in the number of correct responses and interference rates in the reverse Stroop task. Furthermore, post-intervention PFC activity was significantly higher. These results suggest that the STP improved inhibitory control in executive function, which is considered as a key symptom of ADHD. The increase in PFC activity further suggests that the STP improves cognition through neural function.
文摘Objective: To explore the effects of the behavioral treatment combined with psychological counseling on female coital disorder in China. Methods: One hundred and sixteen female patients with coital disorder were divided into sexual behavior training combined with psychological counseling group (group A, 59 cases) and psychological counseling alone group (group B, 57 cases). Results: Forty-five cases cured (76.27%), eight eases improved (13.56%), and six cases invalid (10.17%), the general rate of effectiveness being 89.83% in group A while eleven cases cured (19.30%), twenty-one cases improved (36.84%), and twenty-five cases invalid (43.86%), the general rate of effectiveness being 56.14% in group B. The curative effect of group A was better than group B (P Conclusions: The behavioral treatment combined with psychological counseling is significantly effective in treating female coital disorder than psychological counseling alone and its long term follow-up results show that most of patients were satisfied with their sex life. However, the response of behavioral treatment of some patients who had bad experience on sexual things in the progress of their growing up or had long course of disease were not so good which deserves our special attention in the future study.
文摘Children with attention deficit and hyper activity disorder have various problems such as low academic performance, social and communication problems, anxiety, depression, aggression, conduct disorder and delinquency, and also when they become adults, they have problems in social relationships that these problems can increase or decrease in dealing with family. Hence, this study was performed in order to examine the impact of family-based behavioral treatment compared with Barkley behavior therapy in reducing symptoms of children with attention deficit disorder—ADHD. To meet the aim, 20 of children with age range of 7 to 12 years old with attention deficit disorder—hyperactivity were selected in both experimental and control groups, and exposed to the treatment of behavioral family therapy groups and changes in behavior Barkley. Before and after the treatment, they were evaluated according to the scale of the Conner’s Parent Rating Scale-Revised Short Form (CPRS-R: S). Results of multivariate analysis of covariance indicated that there were significant differences between the experimental group who had received family-based behavioral treatments based on changes in behavior Barkley and a control group who had received drug treatment in variables, including conduct problems, learning problems, psychosomatic symptoms, and signs of impulsive hyperactivity, anxiety and hyperactivity (p < 0.01). These results could be guidance for counsel or sand therapists for children with attention deficit disorder—ADHD.
基金Funded by the National Key Technology R&D Program of China
文摘The corrosion behaviors of a basic type of RE-containing magnesium alloy Mg-15Y processed by different heat treatment methods were studied in 3.5% NaC1 solution at room temperature. The amount of Mg24Y5 phase decreased with the extending of homogenization treatment. The time for achieving dissolving equilibrium of homogenization treatment at 525, 535, and 545 ℃ was 24, 20, and 8 h, respectively. The corrosion behavior of Mg-15Y alloy was studied using immersion, hydrogen evolution and electrochemical tests. The experimental results revealed that the heat treatment improved the corrosion resistance, and the corrosion resistance became better with increasing the heat treatment time. The corrosion mode of the alloy after heat treatment was microgalvanic corrosion consisting of the cathodic Mg24Y5 phase and anodic α-Mg matrix, and Mg-15Y exhibited favorable uniform corrosion mode in NaC1 solution. The volume and increasing tendency of the homogenization treatment samples were both more than those of the as-cast sample.
文摘Silicon carbide ceramics were prepared with SiC powder treated by the fluidized bed opposed jet mill as raw materials, and the effects of the ultra-fine treatment mechanism on the compaction and sintering behavior of SiC ceramics were investigated. The results showed that the compacts had higher density and microstructure homogeneity when the sintering temperature of the compact was decreased; and that the surface microstructure, densification and mechanical properties of the sintered body could be ameliorated obviously.
基金Talent Bringing New Ideas Science Foundation of Henan University and the Key Teacher SubsidyPlan of Chinese Universities.
文摘The polymorphic behavior of syndiotactic polypropylene (s-PP) crystallized from the melt under different conditions was investigated by means of WAXD and DSC. The isothermal melt crystallization of s-PP proceeded in form I at tc≥ 110℃ and in form Ⅱ at tc≤110 ℃ s-PP crystallized nonisothermally from the melt was the mixture of forms and . With increasing the cooling rate (a), the content of form increased, and the content of form decreased. On heating, at 10 K/min, of quenched s-PP, it crystallized in form at t≤70 , continuing heating resulted in form form transition, which was an endothermal process.
文摘In Uganda, there is still insufficient comprehension of malaria as a lethal disease especially in rural areas despite universal bed-net distribution coverage and effective anti-malarial treatment. <strong>Aim:</strong> To get evidence-based knowledge to establish the contribution of an individuals’ knowledge from various health communications that could increase their active involvement in health care especially seeking timely appropriate treatment for malaria or suspected malaria. <strong>Method:</strong> A cross-sectional survey using a correlational design was employed on a clustered sample of 380 rural households in 05 sub-counties of Kanungu district. Data were corrected between October 2016-January 2017 using researcher-administered questionnaires, key-informant interviews and focus group discussions. Correlation analysis was done. <strong>Result:</strong> There is a significant positive relationship between knowledge of health communications and treatment-seeking behavior (r = 0.312;<em>p</em> ≤ 0.01). <strong>Conclusion:</strong> Exposure to consistent Behavioral Change Communications messages influences treatment-seeking behaviour. Thus, in malaria-prone communities, it appears that other factors including sufficient targeted persuasive health communication are lacking in influencing personal orientations towards treatment-seeking behaviour. Therefore, proper Health Communications management supplements efforts from other disciplines and players, against malaria in Uganda.
文摘The aim of the study was to evaluate the behavioral signs of diabetic rats after treatment by Artemisia herba-alba (AHA) and insulin. Method: Based on the induction of diabetes in wistar rats by intraperitoneal (I/P) injection of 60 mg/kg streptozotocin (STZ), then treated by AHA as 20 mg (I/P) and insulin subcutaneously (S/C). The samples of rats were: 1) Diabetic control, 2) Injected with insulin, 3) Injected with AHA, 4) Non diabetic rats, which were fostered for 21 day;then weighted and the behavioral tests were conducted. Results: The board hole tests (BHT) showed that: the induced diabetes reduced the cognition of the rats in view of Latency of the First Head Dipping (LFHD) in seconds, number of head dipping (NHD) and duration of head dipping (DHD) by 49.3%, while it’s improved in AHA and insulin treated rats by 52% and 69% in average respectively. The exploratory activity reduced in diabetic rats by 36%, while AHA and Insulin treated rats increased by 53% and 72% respectively. The rearing test showed an increase of anxiety among diabetic in form of duration of rearing, number of rearing and time spend in center by 51.7% in average respectively, while the anxiety reduced after treatment by AHA and insulin by 39% and 47.3% in average respectively. Also the diabetes increased the depression state by 106%, while the treatment by AHA and insulin reduced the depression state by 77% and 88% respectively. And VPT showed that: motor impairment occurred in diabetic cases and improved after AHA and insulin treatment.
文摘Background: Even though domestic violence is a major problem, only a few studies have examined the long term sustainability of treatment for men who voluntarily seek help to stop their violent behavior towards intimate partners. Women are exposed to a much greater degree of serious violence and sexual abuse compared to men. Objective: The aim of this study was to identify which elements of the treatment program batterers found most useful four to seven years after program completion. Design: The participants consisted of a sample of men who had gone through anger management therapy four to seven years previously. Data on violence were collected through self-report before and four to seven years after treatment, using a modified version of the Conflict Tactics Scales. Results: The decrease in physical violence was statistically significant: t (36) = 8.43, p < 0.001 with a large effect size (eta squared = 0.66). Psychological violence also decreased significantly: t (36) = 9.21, p < 0.001 with a large effect size (eta squared = 0.7). The results indicate that the most important anger management techniques were extensively applied in former patients of the anger management treatment program. In total, about two out of three patients still used the techniques after ending treatment four to seven years earlier.
文摘An aluminum alloy (6061) matrix composite reinforced with 35% (vol.) Al 2O 3 particles was fabricated by squeeze casting method. The Al 2O 3 particles were spherical. The microyield behavior of the composite and the effect of different thermal cycling treatment on the microyield behaviors of the composite were studied. Based on TEM and HREM observation of microstructure, the mechanism of microyield behavior in the Al 2O 3p/6061 composite was analyzed. The results indicate that the microyield behavior of the Al 2O 3p/6061 composite can be described by Brown Lukens theory, which was used satisfactorily for aluminum alloys and other light alloys, and is affected greatly by the different thermal cycling treatment. The more the cycles of thermal cycling treatment, the higher to microyield strength at small strains. Thermal cycling treatment affects mainly the thermal mismatch stress and the density of movable dislocations in the matrix.
文摘Background: Late diagnosis of Human Immunodeficiency Virus (HIV) infection and delayed commencement of antiretroviral therapy (ART) in sub-Saharan Africa is known to contribute to high morbidity and mortality. It is therefore, prudent to develop innovative approaches to ensure early HIV diagnosis because patients with low immunity will usually develop opportunistic infections and seek some remedial action. A treatment and health care seeking behavior survey was carried out in semi-urban communities in Malaba and Busia in Kenya and Uganda to evaluate the treatment and healthcare seeking behavior among patients visiting randomly selected drugstores. Methodology: Random sampling was applied and questionnaires were used to collect information from 165 interviewees who visited drugstores seeking health information, treatment and other health related services. Results: The results indicated that among this group of people, 67% visited drugstores before any other health facility. 72.2% sought treatment for various illnesses and services ranging from headaches, body fever, gastro-intestinal disturbances, family planning pills, sexually transmitted infections and chronic medications. Among the patients interviewed, there were a number of factors that affected treatment choice. These included the distance to the facility as well as the absence of a consultation fee or fee for service. Conclusion: With proper support, drugstores can play a major role in the implementation of health interventions that seek to promote early diagnosis and treatment as well as play a pivotal role in educating the population on disease prevention and management. In Sub-Saharan Africa, drugstores can play a major role in HIV and AIDS interventions where most patients seek medical intervention for opportunistic infection.
文摘An experimental study has been carried out to investigate the influence of heat treatment at 300 ℃,450 ℃,550 ℃,650 ℃ and 800 ℃ on the microstructure and sliding wear behavior of Fe Al/WC intermetallic composite coatings produced by high velocity arc spraying (HVAS) and cored wires. The result shows, the main phases in both as sprayed and heat treated Fe Al/WC composite coatings are iron aluminide intermetallics (Fe 3Al+FeAl) and α as well as a little oxide (Al 2O 3) and carbides (WC, W 2C, Fe 2W 2C and Fe 6W 6C). After heat treated at 450-650 ℃, dispersion strengthening of Fe 2W 2C and Fe 6W 6C will lead to a rise in microhardness of the coatings. The microhardness is likely to be the most important factor which influences the sliding wear behavior of the coatings. Increasing the microhardness through heat treatment will improve the sliding wear resistance of the Fe Al/WC composite coatings.