mlsa-iai-msu-lab/ru_sci_bench_zho_cite_reranking huggingface dataset:
Determining Pressure with Daughter Minerals in Fluid Inclusion by Raman Spectroscopy: Sphalerite as an Example

Raman frequency of some materials, including minerals, molecules and ions, shifts systematically with changing pressure and temperature. This property is often used as a pressure gauge in high pressure experiments with the hydrothermal diamond anvil cell (HDAC). Since the system of fluid inclusion is similar to that of HDAC, it can also be used to determine the internal pressure of fluid inclusions. Sphalerite is a common daughter mineral. In this study, the frequency shift of the 350 cm~(-1) peak of sphalerite has been studied from 296 to 523 K and from 0.07 to 2.00 GPa using the HDAC. The global slope of the isotherms ((e)v_(350)/(e)p)_T is 0.0048 in the studied pressure range. No significant variation of the slopes with temperature has been observed. The correlation between the frequency shift of the 350 cm~(-1) peak of sphalerite and pressure and temperature is constrained as P=208.33(△v_p)_(350)+3.13T-943.75. This relationship may be used to estimate the internal pressure of the sphalerite-bearing fluid inclusions.
压力测量不确定度评定基础知识讲座(七)第七讲航空发动机试验中电子扫描压力测量不确定度评定——电子扫描压力测量系统示值误差的测量不确定度评定

1 电子扫描压力测量系统示值误差的不确定度评定示值误差的不确定度评定采用比较法,即利用准确度高的压力标准直接对电子扫描压力测量系统中所有测压通道进行检定.通常,将一稳定的测试压力同时加载到电子扫描压力测量系统各通道和压力标准,并将各通道的显示的压力值与压力标准测量值之差,即示值误差,作为测量结果.在进行不确定度评定时,除了上述示值误差之外,还要考虑压力标准的误差.
边坡变形失稳影响因素分析及GIS评价方法研究

在各类边坡工程建设及矿山的开发与开采中,岩体边坡稳定与否是制约生产效益的主要因素之一.边坡变形失稳地质灾害给工程建设和生产造成的损失是巨大的,准确分析边坡变形失稳影响因素,建立科学合理的评价指标体系,及时准确地预报滑坡空间和规模,可最大限度减少灾害造成的损失,在区域规划、管理决策、灾害防治中有其重大的社会、经济意义.
关于Hardy-Hilbert型积分不等式

设1/p+1/q=1且p>1.通过引入一个适当的积分核函数和参数λ(λ>-1),创建了一种新型的Hardy-Hilbert型积分不等式.证明了其常数因子(pλ+1+qλ+1)Γ(λ+1)是最佳的,其中Γ(x)是Γ-函数.特别,当p=2时,得到了一种新的Hilbert型积分不等式.作为应用,给出了它的一种等价形式.
具无穷时滞的中立型Volterra积分微分方程的概周期解

研究了一类具无穷时滞的中立型Volterra积分微分方程的概周期解问题.利用线性系统指数型二分性理论和泛函分析方法,得到了一些关于该方程的概周期解的存在性、唯一性与稳定性的新结果,推广了相关文献的主要结果.
Evaluation of Impact of Major Causes of Death on Life Expectancy Changes in China, 1990-2005

Objective To evaluate the impact of major causes of death on changes of life expectancy in China. Methods Life expectancy was calculated by standard life table techniques using mortality data from the national censuses in 1990 and 2000 and the 1% National Population Sampling Surveys in 1995 and 2005. Mortality data about the major causes of death from VR-MOH were used as reference values to estimate their death proportions of the specific age groups by sex and regions, as well as all-cause mortality and age-specific mortality rates of major causes of death. Decomposition method was used to quantitatively evaluate the impact. Results Three key findings were identified in our study. First, China's health challenge was shifted from diseases related to living conditions to those related to behavior and lifestyle, with rural areas relatively lagged behind urban areas. Second, the impacts of cardiovascular diseases and neoplasm on the middle aged and elderly population were stressed. Third, compared to the urban population, the rural population tended to have increasing mortality of neoplasm and cardiovascular diseases, especially in adults at the age of 15-39 years. Conclusion Further efforts should be made to reduce the incidence of neoplasm and cardiovascular diseases, especially in rural areas, by promoting healthy behavior and lifestyle and providing appropriate therapies for all patients in need.
恶性肿瘤患者感染状况调查及相关因素分析

目的 通过对恶性肿瘤患者感染状况的调查,了解恶性肿瘤感染的特点,为临床上对于肿瘤患者感染的及时防治,提供充足的理论依据.方法 应用各种平板对采集的标本进行细菌培养,按ATB系统进行细菌鉴定.并以SPSS 13.0统计学软件进行分析、检验.结果 1124例恶性肿瘤患者中,共有68例(6.0%)出现了细菌感染,进一步分析发现性别、年龄、吸烟状态均与恶性肿瘤患者感染具有一定相关性.结论 对于老年、男性、吸烟的中晚期恶性肿瘤患者,特别在中性粒细胞下降后,应高度注意其感染的发生.
乙脑病毒的自然循环与生态阻断

流行性乙型脑炎常简称乙型脑炎或乙脑,国际上称为日本脑炎(Japanese encephalitis),是一种发生于亚太地区的由乙脑病毒引起的中枢神经系统的媒介病毒传染病.
体内埋置静脉化疗泵在乳腺癌化疗中的应用体会

我科于2008年5月至2009年2月利用体内埋置化疗泵替代深静脉留置管用于乳腺癌化疗,效果满意.现报告如下.1一般资料63例病人,均为女性.经活检组织病理诊断为乳腺癌,年龄23～68岁,共完成4～8个化疗周期395疗程.上述病人均采用头静脉置管皮下埋置化疗泵进行化疗,采用紫杉醇类、蒽环类化疗方案,每21～28d为一个疗程.采用体内坪置化疗泵,包括一个充药泵、一根导管及附件.导管外径1.8mm,内径1.2mm,能够在X光下显影.
新生期注射谷氨酸单钠对老年雄性大鼠骨质疏松疗效的影响

目的 探讨新生期注射谷氨酸单钠损毁下丘脑弓状核对老年雄性大鼠骨质疏松疗效的影响.方法 选用24只新生期雄性SD大鼠,随机分成注射谷氨酸单钠对照组(MA)、注射生理盐水对照组(NA)、注射谷氨酸单钠治疗组(MT)、注射生理盐水治疗组(NT),同等条件下饲养至700 d龄,治疗组给予甲基睾丸素和钙剂治疗120 d,处死收集血清行睾酮(T)和雌二醇(E_2)放免检测,取左侧胫骨干骺端行组织形态计量学分析等.结果 与MA组比较,MT组大鼠T和E_2水平明显增加,胫骨干骺端%Tb.Ar、Tb.N、Tb.Th明显增加,但T、E_2水平升高、骨组织计量学参数的变化、骨量的改变、骨质疏松程度减轻等效果比注射生理盐水组大鼠差.结论 弓状核参与了老年雄性大鼠骨质疏松治疗过程的调控,进一步证实了下丘脑弓状核参与骨质疏松形成的调控.
阿托伐他汀对心肌梗死后大鼠梗死区及非梗死区心肌细胞凋亡及血浆BNP水平的影响

目的 通过持续结扎Wistar大鼠前降支冠状动脉制造心肌梗死动物模型,探讨阿托伐他汀对梗死后大鼠梗死区及非梗死区心肌细胞凋亡及血浆B型钠尿肽(BNP)水平的影响.方法 取雄性Wistar大鼠60只,随机取8只作为假手术组,另外52只通过持续结扎前降支冠状动脉建立大鼠动物模型,ELISA法测血清中心脏肌钙蛋白T(CTnT)水平,将CTnT水平大于4.00 ng/ml的31只大鼠随机分为2组,对照组15只,实验组16只.假手术组及对照组正常饮食,实验组给予正常饮食+阿托伐他汀(10 mg·kg~(-1)·d~(-1)),继续喂养5 w后通过ELISA法测血将中BNP水平,流式细胞法测梗死区及非梗死区心肌细胞凋亡率.结果 喂养9 w后测血浆中BNP水平:对照组和实验组高于假手术组(P＜0.05),实验组明显低于对照组(P＜0.05);流式细胞法测梗死区心肌细胞凋亡率:实验组梗死区心肌细胞凋亡率明显低于对照组,实验组非梗死区凋亡率低于对照组;实验组和对照组梗死区和非梗死区心肌细胞凋亡率均高于假手术组(均P＜0.05).结论 阿托伐他汀可以减少心肌梗死后大鼠梗死区及非梗死区心肌细胞凋亡,并降低血浆中BNP水平,在一定程度上起到改善心脏功能作用.
Aerosol pollution in China: Present and future impact on environment

With its dense population, rapid economic growth and dramatic rate of urbanization, China is experiencing extreme air pollution problems. This is particularly the case in Central-Eastern China (CEC), where the two major cities of Beijing and Tianjin are located, in the Yangtze-River Delta (YRD) with the city of Shanghai, and in the Pearl-River Delta (PRD) with the mega-city of Guangzhou. Space observations show that the atmospheric aerosol load in these three regions is considerably higher than, for example, in the urbanized regions of Europe and North America. The high aerosol concentrations in these regions have raised many environmental problems, such as impact on human health, visibility, and climate changes. In this paper, several crucial issues regarding aerosol pollution in these highly populated regions (CEC, YRD, and PRD) are discussed, including (1) when the aerosol load starts to rapidly increase in these regions; (2) how the high aerosol concentrations affects the environment; and (3) what the potential consequences are under possible low aerosol load in these regions. Discussion on these crucial issues might lead to some insight for better understanding of the characterizations of aerosol pollution due to the rapid economical development in China.
Characteristics of organic and elemental carbon in atmospheric fine particles in Tianjin,China

PM_(2.5)samples were collected at urban, industrial and coastal sites in Tianjin during winter, spring and summer in 2007. Concentrations of elemental carbon (EC) and organic carbon (OC) were analyzed using the IMPROVE thermal-optical reflectance (TOR) method. Both OC and EC exhibited a clear seasonal pattern with higher concentrations observed in the winter than in the spring and summer, due to cooperative effect of changes in emission rates and seasonal meteorology. The concentrations of carbonaceous species were also influenced by the local factors at different sampling sites, ranking in the order of industrial > urban > coastal during winter and spring. In the summer, the port emissions, enriched with EC, had a significant impact on carbonaceous aerosols at the coastal site. Total carbonaceous aerosol accounted for 40.0% in winter, 33.8% in spring and 31.4% in summer of PM2.5 mass. Good correlation (R = 0.84-0.93) between OC and EC indicated that they had common dominant sources of combustion such as coal burning and traffic emissions. The daily average OC/EC ratios ranged from 2.1 to 9.1, the elevated OC/EC ratios being found in the winter. The estimated secondary organic carbon (SOC) accounted for 46.9%, 35.3% and 40.2% of the total OC in the winter, spring and summer, respectively, indicating that SOC may be an important contributor to fine organic aerosol in Tianjin.
高性能各向异性粘结钕铁硼磁粉及其对电机设计的影响

引言粘结钕铁硼磁粉已广泛用于电子工业(如HDD和0DD的驱动电机)、家电(如空调和冰箱的风扇电机)和汽车部件(直流无刷电动机)领域.随着时代的进步,消费者对电机的要求在不断提高,即体积更小,重最更轻,效率更高,价格合理,这都要求更高性能的粘结钕铁硼磁粉的出现.目前虽然HDDR磁粉已开发成功,但在国内尚未形成批量生产,价格也居高不下,因此开发并批量生产新型各向异性粘结钕铁硼磁粉成为市场的迫切需求.
Storage and Spatial Variation of Phosphorus in Paddy Soils of China

Due to the growing concern about the agricultural phosphorus (P) losses pollution,an in-depth understanding of P in paddy soils of China would be helpful in providing a national perspective of the environmental impact of P cycling and fertility on China's farms.In this study,we evaluated the P storage and the P density of paddy soils in China,characterized the spatial variations of P among the subgroups of paddy soils and soil regions in China,and evaluated the P data using GIS-based analysis,which included a newly compiled 1:1000000 digital soil map of China,and using 1490 soil profiles.The available and total P densities of paddy soils were 6.7 and 698.5 g m~(-3),respectively.Overall in China,the total P storage within 1 m of paddy soils was estimated to be 330.2 Tg.The P density of paddy soils varied substantially with subgroups due to the different soil water regimes such as groundwater table and soil drainage.The P availability in paddy soils,especially in surface layer,was higher in high temperature and precipitation areas.Further research is needed to examine more anthropogenic impact factors,such as increasing use of chemical fertilizer.
Temporal and Spatial Dynamics of Bacterial Community in the Rhizosphere of Soybean Genotypes Grown in a Black Soil

The dynamics of rhizosphere microbial communities is important for plant hcalth and productivity,and can be influenced by soil type,plant species or genotype,and plant growth stage.A pot experiment was carried out to examine the dynamics of microbial communities in the rhizosphere of two soybean genotypes grown in a black soil in Northeast China with a long history of soybean cultivation.The two soybean genotypes,Beifeng 11 and Hai 9731,differing in productivity were grown in a mixture of black soil and siliceous sand.The bacterial communities were compared at three zone locations including rhizoplane,rhizospherc,and bulk soil at the third node (V3),early flowcring (R1),and early pod (R3) stages using polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) of 16S rDNA.The results of principal component analyses (PCA) showcd that the bacterial community structure changed with growth stage.Spatially,the bacterial communities in the rhizoplanc and rhizosphere were significantly different from those in the bulk soil.Nevertheless,the bacterial communities in the rhizoplane were distinct from those in the rhizosphere at the V3 stage,while no obvious differences werc found at the R1 and R3 stages.For the two genotypes,the bacterial community structure was similar at the V3 stage,but differed at the R1 and R3 stages.In other words,some bacterial populations became dominant and some others recessive at the two later stages,which contributed to the variation of the bacterial community between the two genotypes.These results suggest that soybean plants can modify the rhizosphere bacterial communities in the black soil,and there existed genotype-specific bacterial populations in the rhizosphere,which may be related to soybean productivity.
Spatial Variability of Micronutrients in Rice Grain and Paddy Soil

Consumption of rice is the main source of mieronutrients to human in Asia.A paddy field with unknown anthropogenic contamination in Deqing County,Zhejiang Province,China was selected to characterize the spatial variability and distribution of micronutrients in rice grain and soil A total of 96 paired soil and rice grain samples were collected at harvest.The micronutrients in the soil samples were extracted by diethylenetriamine pentaacetic acid (DTPA).The mean micronutrient concentrations in rice grain were 3.85 μg Cu g~(-1),11.6 μg Fe g~(-1),39.7 μg Mn g~(-1),and 26.0 μg Zn g~(-1).The mean concentrations were 2.54 μg g~(-1) for DTPA-Cu,133.5 μg g~(-1) for DTPA-Fe,30.6 μg g~(-1) for DTPA-Mn,and 0.84 μg g~(-1) for DTPA-Zn.Semivariograms showed that measured mieronutrients in rice grain were moderately dependent,with a range distance of about 110 m.The conccntrations of the DTPA-extractable micronutrients all displayed strong spatial dependency,with a range distance of about 60 m.There was some resemblance of spatial structure between soil pH and the grain Cu,Fe,Mn,and Zn.By analogy,similar spatial variation was observed between soil organic matter (SOM) and DTPA-extractable micronutrients in the soil.Kriging cstimated maps of the attributes showed the spatial distributions of the variables in the field,which is beneficial for better understanding the spatial variation of micronutrients and for potentially refining agricultural management practices at a field scale.
Effect of Long-Term Fertilization on Organic Carbon and Nitrogen in a Subtropical Paddy Soil

A long-term experiment beginning in 1981 in Jinxian County of Jiangxi Province,subtropical China,was conducted in a paddy field under a double rice cropping system with four different fertilization regimes,including 1) no fertilizer as control (CK),2) balanced chemical N,P,and K fertilizers (NPK),3) organic manure using milk vetch and pig manure in the early and late rice growing season,respectively (OM),and 4) balanced chemical fertilizers combined with organic manure (NPKM).Samples (0-17 cm) of the paddy field soil,which was derived from Quaternary red clay,were collected after the late rice harvest in November 2003 for determination of total organic carbon (TOC) and total nitrogen (TN) and fractions of organic C and N.Results showed that TOC and TN in the NPKM and OM treatments were significantly higher than those in other two treatments (CK and NPK).Application of organic manure with or without chemical fertilizers significantly increased the contents of all fractions of organic C and N,whereas chemical fertilizer application only increased the contents of occluded particulate organic C (oPOC) and amino acid N.In addition,application of organic manure significantly enhanced the proportions of free particulate organic carbon (fPOC) and oPOC in total C,and those of amino sugar N and amino acid N (P＜0.01) in total N.In contrast,chemical fertilizer application only increased the proportions of oPOC and amino acid N (P＜0.05).There were no significant differences in either contents or proportions of soil organic C and organic N fractions between the NPKM and OM treatments.These indicated that organic manure application with or without chemical fertilizers played the most significant role in enhancing soil organic C and N quantity and quality in the paddy field studied.
Precipitation Pulses and Soil CO_2 Emission in Desert Shrubland of Artemisia ordosica on the Ordos Plateau of Inner Mongolia, China

Precipitation is the major driver of ecosystem functions and processes in semiarid and arid regions.In such waterlimited ecosystems,pulsed water inputs directly control the belowground processes through a series of soil drying and rewetting cycles.To investigate the effects of sporadic addition of water on soll CO_2 efflux,an artificial precipitation event (3 mm) was applied to a desert shrub ecosystem in the Mu Us Sand Land of the Ordos Plateau in China.Soil respiration rate increased 2.8-4.1 times immediately after adding water in the field,and then it returned to background level within 48 h.During the experiment,soil CO_2 production was between 2 047.0 and 7 383.0 mg m~(-2).In the shrubland,soil respiration responses showed spatial variations,having stronger pulse effects beneath the shrubs than in the interplant spaces.The spatial variation of the soil respiration responses was closely related with the heterogeneity of soil substrate availability.Apart from precipitation,soil organic carbon and total nitrogen pool were also identified as determinants of soil CO_2 loss in desert ecosystems.
Estimation of As and Cu Contamination in Agricultural Soils Around a Mining Area by Reflectance Spectroscopy :A Case Study

Concentrations of Iron (Fe),As,and Cu in soil samples from the fields near the Baoshan Mine in Hunan Province,China,were analyzed and soil spectral reflectance was measured with an ASD FieldSpec FR spectroradiometer (Analytical Spectral Devices,Inc.,USA) under laboratory condition.Partial least square regrcssion (PLSR) models were constructed for predicting soil metal concentrations.The data pre-processing methods,first and second derivatives (FD and SD),baseline correction (BC),standard normal variate (SNV),multiplicative scatter corrcction (MSC),and continuum removal (CR),were used for the spectral reflectance data pretreatments.Then,the prediction results were evaluated by relative root mean square error (RRMSE) and coefficients of determination (R~2).According to the criteria of minimal RRMSE and maximal R~2,the PLSR models with the FD pretreatment (RRMSE=0.24,R~2=0.61),SNV pretreatment (RRMSE =0.08,R~2=0.78),and BC-pretreatment (RRMSE=0.20,R~2=0.41) were considered as the final models for predicting As,Fe,and Cu,respectively.Wavebands at around 460,1 400,1 900,and 2 200 nm were selected as important spectral variables to construct final models.In conclusion,concentrations of heavy metals in contaminated soils could be indirectly assessed by soil spectra according to the correlation between the spectrally featureless components and Fe;therefore,spectral reflectance would be an alternative tool for monitoring soil heavy metals contamination.
On Integrable Roots in Split Lie Triple Systems

We focus on the notion of an integrable root in the framework of split Lie triple systems T with a coherent 0-root space. As a main result, it is shown that if T has all its nonzero roots integrable, then its standard embedding is a split Lie algebra having all its nonzero roots integrable. As a consequence, a local finiteness theorem for split Lie triple systems, saying that whenever all nonzero roots of T are integrable then T is locally finite, is stated. Finally, a classification theorem for split simple Lie triple systems having all its nonzero roots integrable is given.
Recovery of infectious foot-and-mouth disease virus from full-length genomic cDNA clones using an RNA polymerase I system

The prototypic foot-and-mouth disease virus (FMDV) was shown more than a century ago to be the first filterable agent capable of causing FMD, and it has served as an important model for studying basic principles of Aphthovirus molecular biology. However, the complex structure and antigenic diversity of FMDV have posed a major obstacle to the attempts at manipulating the infectious virus by reverse genetic techniques. Here, we report the recovery of infectious FMDV from cDNAs based on an efficient in vivo RNA polymerase I (poll) transcription system. Intracellular transcription of the full-length viral genome from poll-based vectors resulted in efficient formation of infectious virus displaying a genetic marker. Compared with wild-type virus, an abundance of genomic mRNA and elevated expression levels of viral antigens were indicative of the hyperfunction throughout the life-cycle of this cDNA-derived virus at transcription, replication, and translation levels. The technology described here could be an extremely valuable molecular biology tool for studying FMDV complex infectious characteristics. It is an operating platform for studying FMDV functional genomics, molecular mechanism of pathogenicity and variation, and lays a solid foundation for the development of viral chimeras toward the prospect of a genetically engineered vaccine.
病态肥胖患者的麻醉一例

1 临床资料 患者女,17岁.因病态肥胖,于全身麻醉下行腹腔镜胃间隔捆扎术.身高163 cm,体重210 kg;丙氨酸转氨酶160 U/L,天冬氨酸转氨酶104 U/L;B超检查示脂肪肝,胸部X线摄片示心影增大;其余检查正常.术前12 h禁食,术前30 min予阿托品0.5 mg肌内注射.
585nm脉冲染料激光治疗玫瑰痤疮24例临床观察

1 资料和方法2007年11月至2009年1月我们采用了美国赛诺秀公司585nm脉冲染料激光治疗玫瑰痤疮24例,24例玫瑰座疮患者均来源门诊,女13例、年龄17岁至43岁,男10例、年龄14岁至61岁.病程6个月至35年.皆为红斑期患者.近1月来末曾接受其它治疗方法.
文化差异对农村大学生道德社会化的影响

我国是一个城乡二元结构的社会,也就造成了城乡文化上的差异.从农村走出来的大学生面临城乡文化差异时,原有的道德体系受到严重的冲击.介绍了风俗习惯、教育环境、生活方式对农村大学生道德社会化的影响.
Towards Characterization of the Chloroplast NAD(P)H Dehydrogenase Complex

The NAD(P)H dehydrogenase (NDH) complex in chloroplast thylakoid membranes functions in cyclic electron transfer, and in chlororespiration. NDH is composed of at least 15 subunits, including both chloroplast- and nuclearncoded proteins. During the past few years, extensive proteomic and genetic research on the higher plant NDH complex has been carried out, resulting in identification of several novel nuclear-encoded subunits. In addition, a number of auxiliary proteins, which mainly regulate the expression of chloroplast-encoded ndh genes as well as the assembly and stabilization of the NDH complex, have been discovered and characterized. In the absence of detailed crystallographic data,the structure of the NDH complex has remained obscure, and therefore the role of several NDH-associated nuclear-encoded proteins either as auxiliary proteins or structural subunits remains uncertain. In this review, we summarize the current knowledge on the subunit composition and assembly process of the chloroplast NDH complex. In addition, a novel oligomeric structure of NDH, the PSI/NDH supercomplex, is discussed.
Chloroplast Proteins without Cleavable Transit Peptides: Rare Exceptions or a Major Constituent of the Chloroplast Proteome?

Most chloroplast proteins (cp proteins) are nucleus-encoded, synthesized on cytosolic ribosomes as precursor proteins containing a presequence (cTP), and post-translationally imported via the Tic/Toe complex into the organelle,where the cTP is removed. Only a few unambiguous instances of cp proteins that do not require cTPs (non-canonical cp proteins) have been reported so far. However, the survey of data from large-scale proteomic studies presented here suggests that the fraction of such proteins in the total cp proteome might be as large as～30%. To explore this discrepancy,we chose a representative set of 28 putative non-canonical cp proteins, and used in vitro import and Red Fluorescent Protein (RFP)-fusion assays to determine their sub-cellular destinations. Four proteins, including embryo defective 1211, glycolate oxidase 2, protein disulfide isomerase-like protein (PDII), and a putative glutathione S-transferase, could be unambiguously assigned to the chloroplast. Several others ('potential cp proteins') were found to be imported into chloroplasts in vitro, but failed to localize to the organelle when RFP was fused to their C-terminal ends. Extrapolations suggest that the fraction of cp proteins that enter the inner compartments of the organelle, although they lack a cTP, might be as large as 11.4% of the total cp proteome. Our data also support the idea that cytosolic proteins that associate with the cp outer membrane might account for false positive cp proteins obtained in earlier studies.
Effects of process parameters on arc shape and penetration in twin-wire indirect arc welding

In this study, the effects of variable parameters on arc shape and depth of penetration in twin-wire indirect arc gas shielded welding were investigated. The variation of arc shape caused by changes of the parameters was recorded by a high-speed camera,and the depths of penetration of specimen were measured after bead welding by an optical microscope. Experiments indicated that proper parameters give birth to a concentrated and compressed welcimg arc, which Would increase the depth of penetration as the incensement of the arc foice Several pnncipal parameters including toe distance ot twin wires intersecting point to base metal,the included angle,and the content of shielding gas were determined. The arc turned more concentrated and the depth of penetration increased obviously as the welding current increased,the arc turned brighter while unobvlous change of penetration occurred as the arc voltage increased,and the deepest penetration was obtained when the welding speed was 10.5 mm/s..