期刊文献+
共找到3,464篇文章
< 1 2 174 >
每页显示 20 50 100
Low Birth Weight and Intermittent Preventive Treatment of Malaria in Pregnant Women in Lomé (Togo) in 2021: A Cross-Sectional Study
1
作者 Roméo Mèdéssè Togan Ounoo Elom Takassi +7 位作者 Fifonsi Gbeasor-Komlanvi Arnold Junior Sadio Rodion Yao Konu Martin Kouame Tchankoni Iwone Oumarou Adama Latame Komla Adoli Dzayissé Yawo Atakouma Didier Koumavi Ekouévi 《Open Journal of Epidemiology》 2024年第1期31-44,共14页
Background: Since 2012, the World Health Organization has recommended intermittent preventive treatment with sulfadoxine-pyrimethamine (IPT-SP) to prevent malaria-related complications in pregnant women. Ten years fol... Background: Since 2012, the World Health Organization has recommended intermittent preventive treatment with sulfadoxine-pyrimethamine (IPT-SP) to prevent malaria-related complications in pregnant women. Ten years following these recommendations, we conducted this study to estimate the coverage for three doses of IPT-SP (IPT3) as well as the prevalence of low birth weight (LBW), and its associated factors in Lomé (Togo) in 2021. Methods: A cross-sectional study was conducted between January and March 2021. An exhaustive recruitment of women and their newborns was carried out in the maternity wards of the Sylvanus Olympio University Hospital Center. Data from antenatal consultations and clinical data of the newborns were collected. Multivariate logistic regression was carried out to determine factors associated with LBW. Results: A total of 252 mother-child pairs were included in this study. Median age of the mothers was 27 years, IQR [24-31]. More than a third (35.3%) of the mothers were primigravida. IPT3 coverage was 66.7% and 14.7% of newborns had a LBW. The prevalence of LBW was 33.3% [23.3-43.4] in women who had received fewer than 3 doses of IPT-SP and 5.4% [2.0-8.8] in those who had received at least 3 doses of IPT-SP (p Conclusion: Ten years following recommendations of the WHO on IPT-SP, malaria prevention based on IPT-SP is not optimal among pregnant women in Lomé, and the proportion of LBW children remains high. Actions to strengthen the three-dose IPT-SP policy are needed to prevent malaria and its consequences among newborns in Togo. 展开更多
关键词 MALARIA Intermittent Preventive treatment low Birth Weight TOGO
下载PDF
Mechanical properties of Mg-6Gd-1Y-0.5Zr alloy processed by low temperature thermo-mechanical treatment 被引量:1
2
作者 李德江 曾小勤 +3 位作者 谢艳才 吴玉娟 丁文江 陈彬 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2012年第10期2351-2356,共6页
An as-solution treated Mg-6Gd-1Y-0.4Zr alloy was processed by low temperature thermo-mechanical treatments (LT-TMT), including cold tension with various strains followed by aging at 200 °C to peak hardness. The... An as-solution treated Mg-6Gd-1Y-0.4Zr alloy was processed by low temperature thermo-mechanical treatments (LT-TMT), including cold tension with various strains followed by aging at 200 °C to peak hardness. The results show that the precipitation kinetics of the alloy experienced LT-TMT is greatly accelerated and the aging time to peak hardness is greatly decreased with increasing tensile strain. The tensile yield strength, ultimate tensile strength and elongation at room temperature of the alloy after cold tension with strain of 10% and peak aging at 200 °C are 251 MPa, 296 MPa and 8%, respectively, which are superior to the commercial heat-resistant WE54 alloy, although the latter has a higher rare earth element content. 展开更多
关键词 Mg-Gd-Y-Zr alloy low temperature thermo-mechanical treatment precipitation hardening mechanical properties
下载PDF
Effect of low temperature thermo-mechanical treatment on microstructures and mechanical properties of TC4 alloy 被引量:8
3
作者 孙利平 林高用 +1 位作者 刘健 曾菊花 《Journal of Central South University》 SCIE EI CAS 2010年第3期443-448,共6页
The effects of low temperature thermo-mechanical treatment (LTTMT) on microstructures and mechanical properties of Ti-6Al-4V (TC4) alloy were studied by optical microscopy (OM), tensile test, scanning electron m... The effects of low temperature thermo-mechanical treatment (LTTMT) on microstructures and mechanical properties of Ti-6Al-4V (TC4) alloy were studied by optical microscopy (OM), tensile test, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The experimental results confirm that the strength of TC4 alloy can be improved obviously by LTTMT processing, which combines strain strengthening with aging strengthening. The effect of LTTMT on the alloy depends on the microstructure of the refined and dispersed a+fl phase on the basis of high dislocation density by pre-deformation below recrystallization temperature. The tensile strength decreases with the increase of pre-deformation reduction. The optimal processing parameters of LTTMT for TC4 alloy are as follows: solution treatment at 900 ℃ for 15 min, pre-deformation in the range of 600-700 ℃ with a reduction of 35%, finally aging at 540 ℃ for 4 h followed by air-cooling. 展开更多
关键词 Ti-6Al-4V (TC4) alloy low temperature thermo-mechanical treatment MICROSTRUCTURE mechanical properties strain strengthening
下载PDF
Effect of Low Temperature Treatment on Agrobacterium-mediated Transformation of Maize Seed Buds 被引量:1
4
作者 Mengyu LYU Fushuang DONG +6 位作者 Junmin ZHANG He ZHAO Jianfang CHAI Shuo ZHOU Fan YANG Yongwei LIU Haibo WANG 《Agricultural Biotechnology》 CAS 2018年第3期75-76,共2页
[Objectives]This study was conducted to improve the genetic transformation rate of maize. [Methods]The seeds of maize " Zheng 58" as the experimental material were germinated and treated under freezing temperature o... [Objectives]This study was conducted to improve the genetic transformation rate of maize. [Methods]The seeds of maize " Zheng 58" as the experimental material were germinated and treated under freezing temperature of-18 ℃ for 30 and 35 min. The EGFP gene was transformed into the growth points of these seed buds by Agrobacterium tumefaciens EHA105. The transformation effect was determined by fluorescence protein detection on transformed buds. [Results]After a certain period of treatment at-18 ℃ following germination and transformation of maize bud growth points with A. tumefaciens,although the survival rate of maize buds was reduced,the percentage of transformed cells significantly increased. [Conclusions]Low temperature treatment can improve the transformation efficiency of A. tumefaciens to the growth point of maize bud. 展开更多
关键词 Maize buds low temperature treatment AGROBACTERIUM TRANSGENIC
下载PDF
Effects of low level laser treatment on the survival of axotomized retinal ganglion cells in adult Hamsters 被引量:1
5
作者 Kwok-Fai So Mason Chin Pang Leung Qi Cui 《Neural Regeneration Research》 SCIE CAS CSCD 2014年第21期1863-1869,共7页
Injury to axons close to the neuronal bodies in the mammalian central nervous system causes a large proportion of parenting neurons to degenerate. It is known that optic nerve transection close to the eye in rodents l... Injury to axons close to the neuronal bodies in the mammalian central nervous system causes a large proportion of parenting neurons to degenerate. It is known that optic nerve transection close to the eye in rodents leads to a loss of about half of retinal ganglion cells in 1 week and about 90% in 2 weeks. Using low level laser treatment in the present study, we demonstrated that treatment with helium-neon (660 nm) laser with 15 mW power could delay retinal ganglion cell death after optic nerve axotomy in adult hamsters. The effect was most apparent in the ifrst week with a short period of treatment time (5 minutes) in which 65–66% of retinal ganglion cells survived the optic nerve axotomy whereas 45–47% of retinal ganglion cells did so in optic nerve axotomy controls. We also found that single dose and early commencement of laser irradiation were important in protecting retinal ganglion cells following optic nerve axotomy. These ifndings thus convincingly show that appropriate laser treatment may be neuroprotective to retinal gan-glion cells. 展开更多
关键词 low level laser treatment retinal ganglion cells optic nerve injury NEUROPROTECTION mi-croglial proliferation optic nerve axotomy
下载PDF
Fretting Wear Behavior of Medium Carbon Steel Modified by Low Temperature Gas Multi-component Thermo-chemical Treatment 被引量:3
6
作者 LUO Jun ZHENG Jianfeng PENG Jinfang HE Liping ZHU Minhao 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2010年第3期288-296,共9页
The introduction of surface engineering is expected to be an effective strategy against fretting damage. A large number of studies show that the low gas multi-component (such as carbon, nitrogen, sulphur and oxygen, ... The introduction of surface engineering is expected to be an effective strategy against fretting damage. A large number of studies show that the low gas multi-component (such as carbon, nitrogen, sulphur and oxygen, etc) thermo-chemical treatment(LTGMTT) can overcome the brittleness of nitriding process, and upgrade the surface hardness and improve the wear resistance and fatigue properties of the work-pieces significantly. However, there are few reports on the anti-fretting properties of the LTGMTT modified layer up to now, which limits the applications of fretting. So this paper discusses the fretting wear behavior of modified layer on the surface of LZ50 (0.48%C) steel prepared by low temperature gas multi-component thermo-chemical treatment (LTGMTT) technology. The fretting wear tests of the modified layer flat specimens and its substrate (LZ50 steel) against 52100 steel balls with diameter of 40 mm are carried out under normal load of 150 N and displacement amplitudes varied from 2 μm to 40 μm. Characterization of the modified layer and dynamic analyses in combination with microscopic examinations were performed through the means of scanning electron microscope(SEM), optical microscope(OM), X-ray diffraction(XRD) and surface profilometer. The experimental results showed that the modified layer with a total thickness of 60 μm was consisted of three parts, i.e., loose layer, compound layer and diffusion layer. Compared with the substrate, the range of the mixed fretting regime(MFR) of the LTGMTT modified layer diminished, and the slip regime(SR) of the modified layer shifted to the direction of smaller displacement amplitude. The coefficient of friction(COF) of the modified layer was lower than that of the substrate in the initial stage. For the modified layer, the damage in partial slip regime(PSR) was very slight. The fretting wear mechanism of the modified layer both in MFR and SR was abrasive wear and delamination. The modified layer presented better wear resistance than the substrate in PSR and MFR; however, in SR, the wear resistance of the modified layer decreased with the increase of the displacement amplitudes. The experimental results can provide some experimental bases for promoting industrial application of LTGMTT modified layer in anti-fretting wear. 展开更多
关键词 fretting wear fretting regimes low temperature gas multi-component thermo-chemical treatment(LTGMTT) modified layer medium carbon steel
下载PDF
Influence of soaking time in deep cryogenic treatment on the microstructure and mechanical properties of low-alloy medium-carbon HY-TUF steel 被引量:1
7
作者 Ahmad Zare S.R.Hosseini 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2016年第6期658-666,共9页
The influence of soaking time in deep cryogenic treatment on the tensile and impact properties of low-alloy medium-carbon HY-TUF steel was investigated in this study. Microstructural studies based on phase distributio... The influence of soaking time in deep cryogenic treatment on the tensile and impact properties of low-alloy medium-carbon HY-TUF steel was investigated in this study. Microstructural studies based on phase distribution mapping by electron backscatter diffraction show that the deep cryogenic process causes a decrease in the content of retained austenite and an increase in the volume fraction of η-carbide with increasing soaking time up to 48 h. The decrease in the content of retained austenite from ~1.23vol% to 0.48vol% suggests an isothermal martensitic transformation at 77 K. The η-type precipitates formed in deep cryogenic-treated martensite over 48 h have the Hirotsu and Nagakura orientation relation with the martensitic matrix. Furthermore, a high coherency between η-carbide and the martensitic matrix is observed by high-resolution transmission electron microscopy. The variations in macrohardness, yield strength, ultimate tensile strength, and ductility with soaking time in the deep cryogenic process show a peak/plateau trend. 展开更多
关键词 low alloy steel medium carbon steel cryogenic treatment microstructure mechanical properties fractography
下载PDF
Promoting axonal regeneration following nerve surgery: a perspective on ultrasound treatment for nerve injuries 被引量:3
8
作者 Konstantin D. Bergmeister Simeon C. Daeschler +4 位作者 Patrick Rhodius Philipp Schoenle Arne Bocker Ulrich Kneser Leila Harhaus 《Neural Regeneration Research》 SCIE CAS CSCD 2018年第9期1530-1533,共4页
Nerve injury is often associated with limited axonal regeneration and thus leads to delayed or incomplete axonal reinnervation.As a consequence of slow nerve regeneration,target muscle function is often insufficient a... Nerve injury is often associated with limited axonal regeneration and thus leads to delayed or incomplete axonal reinnervation.As a consequence of slow nerve regeneration,target muscle function is often insufficient and leads to a lifelong burden.Recently,the diagnosis of nerve injuries has been improved and likewise surgical reconstruction has undergone significant developments.However,the problem of slow nerve regeneration has not been solved.In a recent meta-analysis,we have shown that the application of low-intensity ultrasound promotes nerve regeneration experimentally and thereby can improve functional outcomes.Here we want to demonstrate the experimental effect of low intensity ultrasound on nerve regeneration,the current state of investigations and its possible future clinical applications. 展开更多
关键词 peripheral nerve injuries nerve regeneration REINNERVATION experimental studies low-intensityultrasound adjunct treatment nerve reconstruction nerve surgery axonal injury
下载PDF
Effects of Low Temperature Treatment on Bolting of Radish(Raphanus sativus L.)
9
作者 Xiaowei YUAN Keyou CAO Xingsheng LI 《Agricultural Biotechnology》 CAS 2021年第4期29-31,共3页
[Objectives]This study was conducted to screen out a vernalization method of radish that is more suitable for breeding and hybrid production.[Methods]Eight radish inbred lines with different bolting tolerance were use... [Objectives]This study was conducted to screen out a vernalization method of radish that is more suitable for breeding and hybrid production.[Methods]Eight radish inbred lines with different bolting tolerance were used as the research objects for the experiment.The following three treatments were done:(1)treating at 4℃in the dark with heat preservation for 1,2,3,4,and 5 weeks,respectively~([1]),(2)treating at 4℃in the dark with heat preservation for 3 weeks after 24 h incubation in light at 20℃,and(3)treating under light at a low temperature of 6.5℃for three weeks after cultivating under light at 20℃to 4 true leaves.The effects of low temperature treatment on the bolting and flowering time of different varieties of radish treated at different developmental stages were analyzed.[Results]When comparing these three methods,the low-temperature treatment of wet seeds had a better effect on early bolting of radish and is simpler and more feasible.The effect of treating four-leaf seedlings at 6.5℃was the worst;most radish inbred lines could shorten bolting time when treated at 4℃for one week;and within a certain range,the longer the 4℃treatment time,the better the vernalization effect.Different radish inbred lines had different performances to low temperature treatment.[Conclusions]This study provides a scientific basis for the theoretical research on vernalization of radish. 展开更多
关键词 RADISH low temperature treatment BOLTING Development period
下载PDF
Low cycle fatigue improvement of powder metallurgy titanium alloy through thermomechanical treatment 被引量:1
10
作者 刘彬 刘咏 +2 位作者 何小禹 汤慧萍 陈丽芳 《中国有色金属学会会刊:英文版》 EI CSCD 2008年第2期227-232,共6页
A low-cost β type Ti-1.5Fe-6.8Mo-4.8Al-1.2Nd (mass fraction, %)(T12LCC) alloy was produced by blended elemental powder metallurgy(P/M) method and subsequent thermomechanical treatment. Low cycle fatigue(LCF) behavior... A low-cost β type Ti-1.5Fe-6.8Mo-4.8Al-1.2Nd (mass fraction, %)(T12LCC) alloy was produced by blended elemental powder metallurgy(P/M) method and subsequent thermomechanical treatment. Low cycle fatigue(LCF) behavior of P/M T12LCC alloy before and after thermomechanical treatment was studied. The results show that the LCF resistance of P/M titanium alloy is significantly enhanced through the thermomechanical treatment. The mechanisms for the improvement of LCF behavior are attributed to the elimination of residual pores, the microstructure refining and homogenization. 展开更多
关键词 冶金术 变形热处理 合金材料
下载PDF
Dual Phase Heat Treatment of Low-Alloy Steel 被引量:6
11
作者 HAN Jian-min CUI Shi-hai +1 位作者 LI Wei-jing MA Xiao-yan 《Journal of Iron and Steel Research International》 SCIE CAS CSCD 2005年第5期47-51,共5页
Dual phase heat treatment is an economical and effective way for improving the properties of low carbon steels and low-alloy steel materials. In this paper, the microstructures and mechanical properties of 20MnSi stee... Dual phase heat treatment is an economical and effective way for improving the properties of low carbon steels and low-alloy steel materials. In this paper, the microstructures and mechanical properties of 20MnSi steel treated by different dual phase heat treatment have been studied. The results show that dual phase heat treatment with pre-quenching technique and then heating from room temperature to the critical zone can achieve finer and more homogeneous microstructure than that with pre-normalizing technique and then cooling from austenite zone to the critical zone. Among all factors affecting dual phase heat treatment, quenching temperature at the critical zone and tempering temperature play an important part in mechanical properties. Using proper dual phase heat treatment technique with computer optimized parameters, the yield strength, the elongation and impact toughness of 20MnSi can reach 860 MPa, 16% and 207 MPa respectively. 展开更多
关键词 low-alloy steel dual phase heat treatment MICROSTRUCTURE OPTIMIZATION
下载PDF
Mathematical Model of Decarburization of Ultra Low Carbon Steel during RH Treatment 被引量:1
12
作者 ZHANG Lifeng JING Xuejing +2 位作者 LI Jiying XU Thongbo CAI Kaike(Metallurgy Engineering School, USTB, Beijing 100083, China) 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 1997年第4期19-23,共5页
According to the balance of carbon and oxygen, a decarburization model for the RH treatment has been developed. in which the influence of the mass transfer of carbon and oxygen in the liquid steel and the stirring ene... According to the balance of carbon and oxygen, a decarburization model for the RH treatment has been developed. in which the influence of the mass transfer of carbon and oxygen in the liquid steel and the stirring energy (ε) in the vacuum vessel on decarburization rate has been considered. The conclusion that the volumetric coefficients of the mass transfer of carbon is proportional to ε(1.5) is drawn. Industrical experiment proves this model is reliable. The influence of some factors on decarburization rate has been obtained. which can provide directions for RH treatment The decarburization behavior of steel with RH-OB treatment is also studied. The OB-or-not curve, the optimized OB time and OB amount are discussed. 展开更多
关键词 RH treatment ultra-low carbon steel decarburization behavior mathematical model
下载PDF
Pathophysiology, diagnosis, and treatment of discogenic low back pain 被引量:43
13
作者 Bao-Gan Peng 《World Journal of Orthopedics》 2013年第2期42-52,共11页
Discogenic low back pain is a serious medical and social problem, and accounts for 26%-42% of the patients with chronic low back pain. Recent studies found that the pathologic features of discs obtained from the patie... Discogenic low back pain is a serious medical and social problem, and accounts for 26%-42% of the patients with chronic low back pain. Recent studies found that the pathologic features of discs obtained from the patients with discogenic low back pain were the formation of the zones of vascularized granulation tissue, with extensive innervation in fissures extending from the outer part of the annulus into the nucleus pulposus. Studies suggested that the degeneration of the painful disc might originate from the injury and subsequent repair of annulus fibrosus. Growth factors such as basic fibroblast growth factor, transforming growth factor β1, and connective tissue growth factor, macrophages and mast cells might play a key role in the repair of the injured annulus fibrosus and subsequent disc degeneration. Although there exist controversies about the role of discography as a diagnostic test, provocation discography still is the only available means by which to identify a painful disc. A recent study has classified discogenic low back pain into two types that were annular disruption-induced low back pain and internal endplate disruption-induced low back pain, which have been fully supported by clinical and theoretical bases. Current treatment options for discogenic back pain range from medicinal anti-inflammation strategy to invasive procedures including spine fusion and recently spinal arthroplasty. However, these treatments are limited to relieving symptoms, with no attempt to restore the disc's structure. Recently, there has been a growing interest in developing strategies that aim to repair or regenerate the degenerated disc biologically. 展开更多
关键词 Intervertebral DISC Degeneration DIAGNOSIS treatment DISCOGENIC low back pain Classification INTERNAL DISC DISRUPTION INTERNAL annular DISRUPTION INTERNAL ENDPLATE DISRUPTION
下载PDF
Analysis of the formation conditions and characteristics of interphase and random vanadium precipitation in a low-carbon steel during isothermal heat treatment 被引量:5
14
作者 Sayed Ghafar Hashemi B.Eghbali 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2018年第3期339-349,共11页
The characteristics of nanosized precipitates in steels depend on the heat-treatment parameters. The effects of characteristics of vanadium precipitates formed during isothermal heat treatment on the hardness of the f... The characteristics of nanosized precipitates in steels depend on the heat-treatment parameters. The effects of characteristics of vanadium precipitates formed during isothermal heat treatment on the hardness of the ferrite matrix in low-carbon vanadium-alloyed steel were investigated through analysis of transmission electron microscopy images and microhardness measurements. The results show that, during isothermal holding in the temperature range from 675 to 750℃, only interphase precipitation occurs, whereas only random precipitation occurs in the ferrite matrix during holding at 600℃. Furthermore, during isothermal heat treatment between 600 and 675℃, both random and interphase precipitates occurred in the ferrite. Nanoscale vanadium carbides with different atomic ratios of vanadium(V) and carbon(C) were the dominant precipitates in the random and interphase precipitates. The sizes of random precipitation carbides were smaller than those of interphase ones. Also, the sample isothermally heat treated at 650℃ for 900s exhibited a higher hardness with a narrower hardness distribution. 展开更多
关键词 low carbon steel VANADIUM CARBIDE PRECIPITATION heat treatment MICROHARDNESS
下载PDF
Influence of heat treatment on microstructure and mechanical properties of low alloy semi-steel 被引量:3
15
作者 QI Mai-shun 《材料科学与工程(中英文版)》 2009年第8期65-68,共4页
关键词 力学性能试验 高温热处理 显微组织 低合金 半钢 综合力学性能 共晶碳化物 扫描电镜
下载PDF
Outcome of Assisted Reproduction Treatment in Women with Extremely Low Antimullerian Hormone (AMH) Levels 被引量:5
16
作者 Munawar Hussain David J. Cahill +1 位作者 Valentine Akande Uma Gordon 《Open Journal of Obstetrics and Gynecology》 2014年第15期961-966,共6页
Purpose: To evaluate age related ovarian response to controlled ovarian hyperstimulation, clinical pregnancy and ongoing pregnancy rates beyond 20 weeks in women undergoing assisted reproduction treatment (ART) with a... Purpose: To evaluate age related ovarian response to controlled ovarian hyperstimulation, clinical pregnancy and ongoing pregnancy rates beyond 20 weeks in women undergoing assisted reproduction treatment (ART) with antimullerian hormone (AMH) levels of <5 pmol/l. Methods: Retrospective analysis of data from 63 women with AMH of In-vitro?fertilization, IVF and intracytoplasmic sperm injection, ICSI) cycle. Results were analyzed after dividing patients in two groups, group 1 included women of ≤38 years and group 2 > 38 years of age. Non parametric variables were expressed as median (Interquartile range) and compared by Kruskal-Wallis test. Categorical variables were expressed as numbers with proportions (%) and compared by Fisher’s exact test. Results: There was no statistical difference in body max index, level of antimullerian hormone (AMH), follicle stimulating hormone (FSH), dose of gonadotrophins used and cycles cancellation rate in two groups. Although number of oocytes retrieved (median 5), clinical pregnancy (18.4%) and ongoing pregnancy rate beyond 20 weeks (18.4%) was higher in group 1, there was no statistical difference between the two groups. There was one miscarriage in group 2. Conclusion: Women with extremely low-serum AMH levels can still have clinical pregnancy and ongoing pregnancies beyond 20 weeks after ART, though chances will be lower than women with normal ovarian reserve. 展开更多
关键词 EXTREMELY low Antimullerian HORMONE Assisted Reproduction treatment Clinical PREGNANCY Ongoing PREGNANCY MISCARRIAGE Rate
下载PDF
Improvement of Linen Fabric Wickability by Low Temperature Plasma Treatment
17
作者 黄家祺 陶肖明 +1 位作者 袁俊华 杨国荣 《Journal of China Textile University(English Edition)》 EI CAS 1999年第2期1-6,共6页
Low temperature plasma treatments were applied to linen with oxygen and argon, various level of discharge power and exposure time. Tbe fabric weight loss increased with the exposure time. Their effects on surface chem... Low temperature plasma treatments were applied to linen with oxygen and argon, various level of discharge power and exposure time. Tbe fabric weight loss increased with the exposure time. Their effects on surface chemical properties and morphology of flax fiber, and fabric wickability were investigated. X - ray photoelec-tron spectroscopy discovered that the surface oxygen content of the plasma treated sample was increased. Formation of voids and cracks on the fiber surface was revealed by the scanning electron microscopy. Fabric wickability first was increased and then decreased with the prolonged exposure. 展开更多
关键词 LINEN low TEMPERATURE PLASMA treatment wick-ability
下载PDF
Effect of CHF_3 Plasma Treatment on the Characteristics of SiCOH Low-k Film
18
作者 邢振宇 叶超 +2 位作者 袁静 徐轶君 宁兆元 《Plasma Science and Technology》 SCIE EI CAS CSCD 2009年第6期674-678,共5页
The characteristics of SiCOH low dielectric constant film treated by a trifluromethane (CHF3) electron cyclotron resonance (ECR) plasma was investigated. The flat-band voltage VFB and leakage current of the Cu/SiC... The characteristics of SiCOH low dielectric constant film treated by a trifluromethane (CHF3) electron cyclotron resonance (ECR) plasma was investigated. The flat-band voltage VFB and leakage current of the Cu/SiCOH/Si structure, and the hydrophobic property of the SiCOH film were obtained by the measurements of capacitance-voltage, current-voltage and water contact angle. The structures of the SiCOH film were also analyzed by Fourier transform infrared spectroscopy and atomic force microscopy. The CHF3 plasma treatment of the SiCOH film led to a reduction in both the fiat-band voltage VFB shift and leakage current of the Cu/SiCOH/Si structure, a decrease in surface roughness, and a deterioration of the hydrophobic property. The changes in the film's characteristics were related to the formation of Si-F bond, the increase in Si-OH bond, and the C:F deposition at the surface of the SiCOH film. 展开更多
关键词 CHFa plasma treatment SiCOH low-k film
下载PDF
Effect of Heat Treatments on Corrosion of Welded Low-Carbon Steel in Acid and Salt Environments
19
作者 Saliu Ojo Seidu Bolarinwa Johnson Kutelu 《Journal of Minerals and Materials Characterization and Engineering》 2013年第3期95-100,共6页
Effect of heat treatment on the corrosion of welded low-carbon steel in 0.3 M and 0.5 M of hydrochloric acid and sodium chloride environments at ambient temperature (25oC) has been investigated. Arc welded low-carbon ... Effect of heat treatment on the corrosion of welded low-carbon steel in 0.3 M and 0.5 M of hydrochloric acid and sodium chloride environments at ambient temperature (25oC) has been investigated. Arc welded low-carbon steel sample of known composition were subjected to the corrosion reagents for 21 days (504 hours). pH and weight loss values were taken at interval of 3 days. Thereafter, weight loss method was used to measure therate of corrosion attack on the heat treated samples at ambient temperature. Results obtained showed that at low concentration, the annealed sample exhibits better corrosion characteristic as compared to the normalized and quenched samples. However, at higher concentration the normalized sample exercised better service performance over the annealed and quenched samples. Thequenched sample was found to have relatively low corrosion performance over the annealed and normalized samples at both low and high concentrations of the media. 展开更多
关键词 low-Carbon Steel HEAT treatmentS Microstructure pH
下载PDF
Effect of Heat Treatment Parameters on the Mechanical and Microstructure Properties of Low-Alloy Steel
20
作者 Mohamed H. Frihat 《Journal of Surface Engineered Materials and Advanced Technology》 2015年第4期214-227,共14页
This study examines the effect of heat treatment at three different temperatures of 800°C, 950°C and 1100°C on the microstructure and mechanical properties of low-alloy steel with an addition of mangane... This study examines the effect of heat treatment at three different temperatures of 800°C, 950°C and 1100°C on the microstructure and mechanical properties of low-alloy steel with an addition of manganese, chrome and lead. To determine an impact of the applied heat treatment operations, testing of mechanical properties and microstructural examinations of the steel with 0.23%, 0.24%, 0.29% and 0.31% C were conducted. This work shows that the mechanical strengths of the alloy steel are improved with increasing the heat treatment temperature. In addition, the microstructure trends toward recrystallized ferrite grains as the heat treatment temperature increases. 展开更多
关键词 low-Alloy Steel HEAT treatment MICROSTRUCTURE MECHANICAL Properties
下载PDF
上一页 1 2 174 下一页 到第
使用帮助 返回顶部