To explore the mechanism of voltage on material removal rate and surface quality,Cu-ECMP simulating experiments were carried out for rubbing pairs of Si3N4/Cu in electrolyte of 30%HEDP+0.02 mol/L BTA,in dynamic and static state.Experimental results show that the passivating region is between 0.2 V and 1.1 V for Cu in electrolyte of 30%HEDP+0.02 mol/L BTA.When anode potential is 0.5 V,the Inhibition Efficiency(IE)even come near to 90%.Material removal rate increases with the increase of voltage in both dynamic and static state.However,the etch pit will apper when voltage is higher.Perfect balance between electrochemical and mechanical action could be obtained when we apply annodic voltage of 0.5 V,and the Material Removal Rate(MRR)reaches quite high,without reducing the surface quality.

Objective To investigate the expression of macrophage migration inhibitory factor(MIF) in serum and villi in early pregnancy and their association with recurrent spontaneous abortion(RSA). Methods A total of 35 RSA patients(RSA group) and 45 normal early pregnant women undergoing artificial abortion(control group) were recruited.The expressions of MIF mRNA and MIF protein in villi and deciduas were determined by SP method;the MIF mRNA expression in villi and deciduas by reverse transcriptase-polymerase chain reaction(RT-PCR);the serum MIF levels were detected by using enzyme-linked immunosorbent assay(ELISA). Results MIF protein was expressed in trophoblastic cells and decidual cells of both groups,the color of MIF in RSA was pale brown,that in the control was dark brown.The expressions of MIF protein and MIF mRNA in the pregnant tissues of RSA group were significantly lower than the control group,showing a significant difference between the two groups(t=7.089-40.610,P<0.01).The serum MIF levels in RSA group were lower than that in the control group(t=8.903,P<0.01).The serum levels of MIF in early pregnancy were positively correlated with the expression of MIF mRNA(r=0.873,0.657;P<0.01),and MIF protein in villi and decidua(r=0.794,0.616;P<0.01). Conclusion Low expression of MIF mRNA and its protein in villi and decidua of RSA patients are probably involved in the pathogenesis of the disease,a decline of serum MIF in early pregnancy is of a predictive role for the occurrence of this condition.

虚拟装配研究中必须考虑实际装配过程中的不确定性因素,真实再现产品的装配过程,才能对产品装配性进行全面、有效的评沽.本文简要分析了目前虚拟装配存在的问题,从实际装配中暴露的问题出发,对影响产品装配质量因素进行分析.重点分析了产品、资源、人员中不确定性因素,分析了这些不确定性因素对装配性评价的影响,探讨了针对这些不确定因素的解决思路.基此给出了虚拟装配技术的发展趋势及下一步研究工作.该研究工作为确定虚拟装配技术的研究方向以及增强其工业级别应用奠定基础.

By analyzing the content of heavy metals of water substance in middle and lower reaches of Second Songhua River,the distribution characteristics of heavy metals were discussed and potential ecological risk of heavy metals in sediment was assessed by the method of potential ecological risk index.Results indicated that the content of heavy metals in water was relatively low,while that of sediment was relatively high.The concentration variation of heavy metals in waters and in sediments along the reach was the same,with the content higher in urban reach than in suburban reach.Potential ecological risk of heavy metals in sediment exhibits middle to very strong,with mercury and cadmium as priority risk.

Analysis of slackwater sediments has become a widely accepted in palaeoflood research. The identification the palaeoflood deposits are important for the study of palaeoflood. This paper reports the identification of the palaeoflood slackwater sediments in the Holocene loess profile in the loess region. We measured the magnetic susceptibility, clay content, CaCO3 and clay/silt ratio, in the HXZ- E profile,Qishuihe River Valley and compared with the loess accumulation. The results show that indexes in the palaeoflood deposits except the third deposit are between the soil and the loess accumulation. These indicate the palaeoflood deposits have the weak pedogenic. Through the research of these indexes we can identity the palaeoflood slackwater sediments from the loess accumulation. This research result is not only practical to the flood control, water resources exploitation and eco- environmental construction for Yangling, a well- known agricultural and high- tech city in River Basin, but scientificly significant to the comprehensive improvement of the eco- environment of the river basin.

Over the past two decades,slackwater sediments analysis has become a widely accepted tool in palaeoflood research.The most important and basic question in palaeoflood study is ascertained the sediments of palaeoflood.This paper reports the identification of the palaeoflood slackwater sediments in the Holocene loess profile in the Guanzhong Basin.Since each flood units in slackwater sediments occur as couplets,so the Bartington susceptibility meter was used to discern the number of couplets as the organic rich deposits cause a magnetic susceptibility variation.Grain size analysis was undertaken to examine the sedimentary characteristics of slackwater seposits.There are abrupt changes in colour,grain size,and sedimentary type between the slackwater deposits and the loess.The clays in the slackwater deposits are much more than loess.

The residual characteristics of hexachlorocyclohexane(HCH) and hexachlorobenzene(HCB) were discussed based on analyzing the contents of 4 isomers of HCH(α-HCH,β-HCH,γ-HCH and δ-HCH)and HCB in agricultural soils in the central part of Jilin Province.The results showed that the four isomers of HCH were detected at different levels in its soils,of which β-HCH and γ-HCH were its major residues.The average concentration of total HCH was 5.09 ng/g with the range from 0.42 to 44.96 ng/g in its soils.The total HCH residues had no obvious difference in the different soil types within the different soil uses.The ratio of α-HCH to γ-HCH was nearly 1,which indicated that the soil environment in this area had been changed or there might be some new pollution sources.The average concentration of total HCB was 5.51 ng/g in its soils,which the total residual concentration of HCB was lower and the residual level in the paddy fields was higher than that in the glebe fields.

The data of Ganzhou land use changes are extracted from RS data of TM and ETM in 1987～2002.Based Arcinfo9.0 of GIS software platform,the paper constitutes the Tupu of land use changes and land arising /declining,analyzing spatiotemporal changes of land use in Ganzhou during 15 years.The result shows that great changes happened in Ganzhou from 1987 to 2002.The area of desertificated land,cultivated land and urban/traffic land is rising,among which,desertificated land produced from grass land,cultivated land and the rest unused land is the most,increased 6.18×104 hm2(60.2%).The secondary growing land,mainly formed by desertificated land and the rest unused land,is cultivated land,increasing by 1.8×104 hm2.The area of grassland,forest land,water land and the rest unused land showed downward trend.The most significant reduction of land use,which transferred to desertificated land and the rest unused land greatly,is grassland Tupu unit,shrinking by 3.74×104 hm2(50.92%).The secondary declining land is the rest unused land,substituted by desertificated land and cultivated land.

目的:确定大孔树脂吸附法分离南果梨黄酮的最佳工艺条件.方法:通过对吸附率及解吸率的测定,确定最佳型号树脂,静态和动态吸附及解吸的相关影响因素.结果:AB-8型大孔树脂最佳,其最佳静态吸附条件:原液的pH及浓度为最佳状态,即pH 5.4,浓度1.02mg/mL.最佳温度为室温25℃,吸附3h,吸附率65%以上,解吸率75%以上;最佳动态解吸条件:上样流速1.0mL/min和解吸流速2.0mL/min,三倍柱床体积的体积分数50%乙醇,解吸率达80.24%.结论:室温下最佳纯化条件:上样液为原液,上样流速为1.0mL/min,三倍柱床体积的50%乙醇洗脱,洗脱流速2.0mL/min,纯化后得率为51.16%.

The analytical results of polycyclic aromatic hydrocarbons(PAHs) in 8 bottom mud samples from middle and lower reaches of Second Songhua River show that the contents of 5 kinds of PAHs and total PAHs vary dramatically with the sampling locations and the contents of these pollutants in the samples from the urban area are higher than those from rural area.The distribution characteristics of PAHs with 2+3 ring and 5-ring compounds from the analytical data in bottom mud samples show that petroleum-derived contamination may be the dominant source in the rural area,while the combustion of fossil fuel may be the possible source in the urban area.The PAHs in bottom mud in the middle and lower reaches of the second Songhua River,especially in the urban area,have stronger ecological risk and may produce negative biological effects.

Organochlonnated pesticides in soils of the middle Jilin province were analyzed with gas chromatography, to understand the present content and composition. Hexachlorocyclohexane (HCH) and dichlorodiphenyltrichloroethane(DDT) were the main kinds of organochlonnated pesticides in the area and aldrin, chlordane, dieldrin, endrin and heptachlor were also detectable to some extent. The total contents of DDT were between 0.02 μg/kg and 69.35 μg/kg, with the average of 3.01 μg/kg. The total contents of HCH were between 0.47 μg/kg and 13.47 μg/kg, with the average of 2.00 μg/kg. p, p'-DDE and p, p'-DDD were the main existing form of DDT and they were mainly the degradation product of DDT input in the past, but a little DDT was input recently. p-HCH was the major isomer of HCH and the lower ratios of α-HCH and γ-HCH indicated that HCH has stayed for long time in soils in this area.

住房问题是哈尔滨近几年讨论的热点问题,也是改善哈尔滨市人民生活的重大课题.本文从哈尔滨市经济、社会发展现状对哈尔滨市住宅的影响出发,对哈尔滨市居住水平现状进行分析,发现哈尔滨市现有住房房价过高,大大超过居民承受能力.消费结构、产业结构的畸形发展导致住宅市场不景气,现有商品房居住小区的配套设施不健全等.进而提出了哈尔滨市住宅市场的出路及发展方向.