Prediction of lime utilization ratio of dephosphorization in BOF steelmaking based on online sequential extreme learning machine with forgetting mechanism

The machine learning models of multiple linear regression(MLR),support vector regression(SVR),and extreme learning ma-chine(ELM)and the proposed ELM models of online sequential ELM(OS-ELM)and OS-ELM with forgetting mechanism(FOS-ELM)are applied in the prediction of the lime utilization ratio of dephosphorization in the basic oxygen furnace steelmaking process.The ELM model exhibites the best performance compared with the models of MLR and SVR.OS-ELM and FOS-ELM are applied for sequential learning and model updating.The optimal number of samples in validity term of the FOS-ELM model is determined to be 1500,with the smallest population mean absolute relative error(MARE)value of 0.058226 for the population.The variable importance analysis reveals lime weight,initial P content,and hot metal weight as the most important variables for the lime utilization ratio.The lime utilization ratio increases with the decrease in lime weight and the increases in the initial P content and hot metal weight.A prediction system based on FOS-ELM is applied in actual industrial production for one month.The hit ratios of the predicted lime utilization ratio in the error ranges of±1%,±3%,and±5%are 61.16%,90.63%,and 94.11%,respectively.The coefficient of determination,MARE,and root mean square error are 0.8670,0.06823,and 1.4265,respectively.The system exhibits desirable performance for applications in actual industrial pro-duction.

Effects of high-volume hemofiltration on alveolar- arterial oxygen exchange in patients with refractory septic shock

BACKGROUND：High-volume hemofiltration （HVHF） is technically possible in severe acute pancreatitis （SAP） patients complicated with multiple organ dysfunction syndrome （MODS）. Continuous HVHF is expected to become a beneficial adjunct therapy for SAP complicated with MODS. In this study, we aimed to explore the effects of fluid resuscitation and HVHF on alveolar- arterial oxygen exchange, the Acute Physiology and Chronic Health Evaluation II （APACHE II） score in patients with refractory septic shock. METHODS：A total of 89 refractory septic shock patients, who were admitted to ICU, the Provincial Hospital affiliated to Shandong University from August 2006 to December 2009, were enrolled in this retrospective study. The patients were randomly divided into two groups： fluid resuscitation （group A, n=41）, and fluid resuscitation plus high-volume hemofiltration （group B, n=48）, The levels of O2 content of central venous blood （CcvO2）, arterial oxygen content （CaO2）, alveolar-arterial oxygen pressure difference P（A-a）DO2, ratio of arterial oxygen pressure/alveolar oxygen pressure （PaO2/ PAO2）, respiratory index （RI） and oxygenation index （OI） were determined. The oxygen exchange levels of the two groups were examined based on the arterial blood gas analysis at different times （0, 24, 72 hours and 7 days of treatment） in the two groups. The APACHE II score was calculated before and after 7-day treatment in the two groups. The levels of CcvO2, CaO2 on day 7 in group A were significantly lower than those in group B （CcvO2：0.60±0.24 vs, 0.72±0.28, P〈0.05; CaO2：0.84±0.43 vs. 0.94±0.46, P〈0.05）. The level of oxygen extraction rate （O2ER） in group A on the 7th day was significantly higher than that in group B （ 28.7±2.4 vs. 21.7±3.4, P〈0.01）. The levels of P（A-a）DO2 and RI in group B on the 7th day were significantly lower than those in group A. The levels of PaO2/PAO2 and OI in group B on 7th day were significantly higher than those in group A （P〈0.05 or P〈0.01）. The APACHE II score in the two groups reduced gradually after 7-day treatment, and the APACHE II score on the 7th day in group B was significantly lower than that in group A （8.2±3.8 vs. 17.2±6.8, P〈0.01）. HVHF combined with fluid resuscitation can improve alveolar- arterial-oxygen exchange, decrease the APACHE II score in patients with refractory septic shock, and thus it increases the survival rate of patients.

OXYGEN ISOTOPE FRACTIONATION IN URANIUM OXIDES

Thermodynamic oxygen isotope factors for uranium oxides have been calculated by means of the modified increment method. The sequence of 18￣O-enrichment in the uranium oxides with respect to the common rock-forming minerals is predicted as follows: spinel < uraninite brannerite hematite < rutile < pitchblende <cassiterite uranium blacks coffinite sedovite UO3 < illite. Two sets of selfconsistent fractionation factors between the uranium oxides and water and between the uranium oxides and the other minerals have been obtained for 0～ 1200℃. The theoretical results are applicable to the isotopic geothermometry of uranium ores when pairing with other gangue minerals in hydrothermal uranium deposits.

Role of Fe/S ratios in the enhancement of uranium bioleaching from a complex uranium ore by Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans consortium

The role of Fe/S ratios(ω, g/g) in the uranium bioleaching from a complex uranium ore by Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans consortium was investigated. The results showed good uranium extraction with over 90% at the Fe/S ratio of 5:0.5, 5:1 and 5:5, while poor extraction(<46%) at the Fe/S ratio of 5:0 and 5:10.Furthermore, the bacterial community analysis based on species-specific gyrB numbers indicated that, absent sulfur or excessive sulfur would be not conducive to the synergistic growth for A. ferrooxidans and A. thiooxidans, and then not conducive to the uranium dissolution. Meanwhile, the sulfur-oxidizers could play an important role in the process of uranium synergistic bioleaching by mixed bacterial consortia. Additionally, the characteristics of mineral residue was detected by SEM-EDS. The results showed appropriate sulfur dosage would change the structure and improve the porosity of passivation substance. Lastly, the uranium dissolution kinetics and biochemical reaction mechanism was analyzed. It indicated that the biochemical reaction coupling iron and sulfur had a pleiotropic effect on the uranium dissolution from the ore particles, appropriate Fe/S ratio is the key factor for uranium bioleaching by chemoautotrophic acidophiles.

Air flow control based on optimal oxygen excess ratio in fuel cells for vehicles

Air flow control is one of the most important control methods for maintaining the stability and reliability of a fuel cell system, which can avoid oxygen starvation or oxygen saturation. The oxygen excess ratio （OER） is often used to indicate the air flow condition. Based on a fuel cell system model for vehicles, OER performance was analyzed for different stack currents and temperatures in this paper, and the results show that the optimal OER was affected weakly by the stack temperature. In order to ensure the system working in optimal OER, a control scheme that includes an optimal OER regulator and a fuzzy control was proposed. According to the stack current, a reference value of air flow rate was obtained with the optimal OER regulator and then the air compressor motor voltage was controlled with the fuzzy controller to adjust the air flow rate provided by the air compressor. Simulation results show that the control method has good dynamic and static characteristics.

STUDY ON NODULE RATIO AND COMPACTED GRAPHITE RATIO OF IRON FLUID TREATED BY RARE EARTH MAGNESIUM ALLOY QUICKLY EXAMINED BY CONCENTRATED DIFFERENCE FIXING OXYGEN

The article uses the method of regression statistics to obtain the regression formula of iron fluid nodule ratio Q and compacted graphite ratio R, through rare earth magnesium treatment. At the same time it has given thejudging figure of Q and R, considering oxygen activity and temperature. When using oxygen activity to judgenodule ratio and compacted graphite ratio of the ironfluid treated by rare earth magnesium alloy, its limit value changes with the change of temperature.

Oxygen and hydrogen isotope ratios of chert from the Sixtymile Formation in Grand Canyon National Park,USA：a warm palaeoclimate,freshwater deposit

New oxygen and hydrogen isotope ratios of chert from middle, intraformational breccias, and upper breccia members of the Sixtymile Formation（SMF） in eastern Grand Canyon National Park（AZ） yield palaeoclimate estimates between 27 and 33℃. The isotopic compositions of cherts define a domain approximately parallel to the meteoric water line when plotted on a δD–δ-（18）O diagram; these data indicate that meteoric water was involved during formation of the chert. In thin section, the absence of interlocking mega quartz（〉35 lm） and silicafilled fractures and veins, along with preserved micromorphological silica fabrics, suggest that the chert has not been permeated by later hydrothermal fluids. Petrographic observations in thin section such as cyclic silica precipitation phases and glaebular micromorphologic fabrics lend support to the interpretation that meteoric waters were involved during chert precipitation. The post 742 Ma SMF has been correlated with diamictite（transition） beds of the Kingston Peak Formation（CA）, which in turn have been interpreted to have been deposited during the Sturtian Ice Age（-750–700 Ma）. Absence of facetted and striated clasts and other diagnostic glaciogenic features in the SMF,an unconformable contact with the stratigraphically older Chuar Group, coupled with warm palaeotemperature data inferred from stable isotope values of chert, tentatively suggest that deposition of sediment in the SMF likely did not take place during the Sturtian Ice Age.

Oxygen Stable Isotopic Ratio in Precipitations in Niigata Prefecture, Japan

Time-course of oxygen stable isotopic ratios （i.e., δ^18O） as well as seasonal variation of δ^18O has been examined to investigate the characteristics, sources and the passing route of precipitations in Niigata Prefecture. The precipitation samples have been mainly collected with a filtrating bulk sampler at the rooftop of Niigata University. Furthermore, backward trajectories analyses have been also conducted for these samples taken sequentially for a short period. Consequently, the following features have been mainly clarified for the precipitations in Niigata Prefecture： （1） the δ^18O values varied between -14.57%o and -3.86%0 in the precipitations of Niigata University; （2） as for the comparison among sampling points, the mean value of δ^18O at seaside spots （i.e., Niigata City： -6.93%0） is larger than that of inland spots （Sanjyo City： -8.68%0）; （3） δ^18O value was generally small in the rainy or typhoon season, and relatively large in summer; （4） decreasing δ^18O content with time is a predominant feature of sequentially sampled rainfalls as predicted by Rayleigh models of atmospheric vapor condensation.

Late Holocene glacier variations indicated by theδ18O of ice core enclosed gaseous oxygen in the central Tibetan Plateau

Theδ18O of ice core enclosed gaseous oxygen(δ18Obub)has been widely used for climate reconstruction in polar regions.Yet,less is known about its climatic implication in the mountainous glaciers as the lack of continuous record.Here,we present a long-term,continuousδ18Obub record from the Tanggula glacier in the central Tibetan Plateau(TP).Based on comparisons of its variation with regional climate and glacier changes,we found that there was a good correlation between the variation of theδ18Obub in this alpine ice core and the accumulation and melting of this glacier.The more developed the firn layer on glacier surface,the more positive theδ18Obub.Conversely,the more intense the glacier melting,the more negative theδ18Obub.Combined with the chronology of ice core enclosed gases,the glacier variations since the late Holocene in the central TP were reconstructed.The result showed that there were four accumulation and three deficit periods of glaciers in this region.The strongest glacier accumulation period was 1610-300 B.C.,which corresponds to the Neoglaciation.The most significant melting period was the last 100 years,which corresponds to the recent global warming.The Medieval Warm Period was relatively significant in the central TP.However,during the Little Ice Age,there was no significant glacier accumulation in the central TP,and even short deficit events occurred.Comparisons of the late Holocene glacier variation in the central TP with glacier and climate variations in the TP and the Northern Hemisphere showed that it was closely related to the North Atlantic Oscillation.

燃料电池系统建模与供气系统控制方法

为了研究燃料电池系统的特性以及空气系统对燃料电池特性的影响,利用Simulink仿真软件对燃料电池系统进行建模,模型包括电压模型、空压机模型、阴极模型、阳极模型.分别通过前馈比例-积分-微分(proportional-integral-differential, PID)和模糊PID对燃料电池空气系统进行控制.结果表明:在负载电流变化时,前馈PID和模糊PID都能够使过氧比达到设定的常数值2.0附近,但模糊PID比前馈PID响应更快,且模糊PID控制下的燃料电池输出功率波动较小,燃料电池系统更加稳定.

超低稀释比熔融制样X射线荧光光谱法测定铀矿石中主次量元素

铀矿属于国家战略性矿产,目前对铀矿石的分析以化学法为主,方法成熟,标准化程度高,但操作复杂,步骤繁琐。而采用X射线荧光光谱法进行分析,样品用量大,无法用于极少量样品分析。选用四硼酸锂和偏硼酸锂混合熔剂,与样品以100∶1的超低稀释比熔融制样,利用波长色散X射线荧光光谱法测定铀矿石中Si、Al、Fe、Ca、Mg、K和U等元素。采用多个铀矿石标准物质和人工配制的工作标准制作标准曲线,理论α系数及康普顿散射内标法校正元素间的吸收增强效应,讨论了样片厚度对于样品测量的影响。方法精密度(RSD,n=10)介于0.7%~3.4%之间,且U元素方法检出限可低至15μg·g^(-1)。采用未参加回归的标准物质验证方法准确度,测量结果均在不确定度范围内。本方法通过选择有效的助熔剂和极低的稀释比,解决了X射线荧光法样品用量大,无法分析极少量样品的问题。

超音速火焰喷涂氧燃比对铁基非晶涂层性能的影响

非晶涂层具有优良的物理和化学性能,在工业中有广泛的应用。以FeCrMoCBSi非晶粉末为喷涂粉末,采用超音速火焰喷涂(HVOF)技术在不同喷涂参数下在Q235钢基板上沉积了铁基非晶涂层。通过X射线衍射仪(XRD)、差示扫描热仪(DSC)、扫描电子显微镜(SEM)、维氏显微硬度计等测试方法,探讨氧燃比对涂层显微组织、微观结构及耐磨性的影响。研究表明,随着喷涂氧燃比的减小,涂层的非晶相含量呈增加趋势。这是因为过量的氧气会降低喷涂过程中颗粒的熔化程度,并使颗粒氧化。涂层的显微硬度和耐磨性随氧燃比的减小而增加。这是因为在较小氧燃比下,颗粒熔化程度增加,与基板间润湿性增加,孔隙率减小。三种铁基非晶涂层相比于Q235钢基板均具有更加优良的耐磨性,有望成为碳钢表面保护和耐磨涂层的候选材料。

增氧条件下粉绿狐尾藻的氮磷吸收特征

为探明增氧处理下粉绿狐尾藻植株的氮磷吸收特征,该研究以粉绿狐尾藻为研究材料,设置5个不同增氧水平(增氧时长),即CK (0 min)、JO1(4 min)、JO_(2)(6 min)、JO3(8 min)、JO4(10 min),系统分析了不同增氧水平下粉绿狐尾藻幼苗期(7月10日—9月15日)、生长旺盛期(9月16日—12月22日)生理指标的变化规律,明确了植株N、P含量、N/P和叶绿素含量、底泥各形态氮磷含量之间的关系。结果表明:增氧8 min时,t_(1)、t_(2)取样时期(9月15日、10月10日)粉绿狐尾藻的氮、磷吸收量及t5取样时期(12月22日)的氮吸收量最高;增氧6 min时,t_(3)、t4取样时期(10月27日、11月16日)粉绿狐尾藻的氮、磷吸收量及t5取样时期的磷吸收量最高;增氧有利于粉绿狐尾藻在t_(1)、t_(2)、t_(3)时期对氮的吸收,t4时期对磷的吸收,表现为t_(1)、t_(2)、t_(3)时期粉绿狐尾藻的植株氮磷比分别增加5.27%~36.57%、9.04%~63.07%、3.50%~73.45%,t4时期的N/P降低1.38%-34.05%;增氧使t_(2)、t5时期粉绿狐尾藻叶片叶绿素a、b及叶绿素总含量降低,t4时期叶绿素含量增加同时,使t_(1)、t_(2)时期底泥氮磷比值(sediment total nitrogen/phosphorus,STN/P)分别降低64.84%、54.76%,t4、t5时期STN/P分别增高138.97%、47.02%;层次聚类分析及多元线性回归分析结果进一步表明,增氧6 min是增氧促进粉绿狐尾藻氮磷吸收利用的理论满意方案,增氧降低t_(1)时期叶绿素a、b含量、t5时期底泥碱解氮含量(sediment alkali-hydro nitrogen,SAHN)和t4时期铁结合态磷(Fe-P)含量同时,促进了粉绿狐尾藻t5时期氮磷的吸收。增氧调控粉绿狐尾藻叶片叶绿素形成和底泥氮磷的形态转化,促进其对底泥氮磷吸收,同时提高了粉绿狐尾藻氮磷的吸收利用效果,可抑制甲烷和氧化亚氮、CO_(2)等温室气体的排放。

污水曝氧工艺技术研究

大庆油田聚驱用聚合物常使用含聚污水进行调配,但含聚污水中存在大量S^(2-)、Fe^(2+)等离子,会对聚合物分子产生严重的降解作用,造成稀释母液时降低溶液黏度,影响驱油效果。为有效清除溶液中还原性离子含量,可采用曝氧工艺对含聚污水进行处理。通过实验,将曝氧气头换为盘式曝氧器,重新设计工艺流程,可提高曝氧效率,节约能耗。盘式曝氧工艺在气水比5∶1,曝氧时间3~6 h条件下,污水溶氧量达到5 mg/L以上,配制黏度提高7.6%以上,能有效降低含聚采出水中的还原性物质含量,聚合物溶液稳定性大幅提升,保证聚驱稀释用水溶氧值满足开发效果。

酸分馏效应对GasBench-IRMS测定碳酸盐碳、氧同位素的影响

本文利用在线制样装置(GasBench)和稳定同位素比质谱仪(IRMS)测试一系列碳酸盐标准物质和现代海洋浮游有孔虫样品,在不同测试条件下,分析不同性状碳酸盐矿物的氧同位素分馏程度,计算氧同位素酸分馏系数,探讨酸分馏效应对不同碳酸盐矿物氧同位素测定的影响机制和控制因素,以及对氧同位素测试值(δ^(18)O_(m))的校正方法。结果表明,酸分馏效应对氧同位素值的影响主要是由于生成的CO_(2)气体与顶空瓶中气态水(高温时主要影响)或酸中游离态自由水(低温时主要影响)之间发生氧同位素交换引起的。不同性状碳酸盐标准物质的氧同位素酸分馏系数具有显著差异,且与氧同位素组成相关。δ^(18)O_(m)值发生偏移的程度与反应温度、样品量、磷酸含水量以及酸中游离态和气态水的氧同位素组成与样品氧同位素组成之间的差异等因素有关。氧同位素酸分馏效应与信号强度具有显著相关性。建议精确称量相同质量的标准物质和样品,遵循信号强度匹配的原则,并采用多种标准物质线性校正的方法有效校正氧同位素分馏现象。在较低的反应温度(25℃)下,氧同位素分馏程度较轻微,δ^(18)O分析精度更高,优于0.05‰。本方法为精确测定碳酸盐中碳、氧同位素组成提供了参考,可有效提高相关的测试精度。

锆石氧逸度对相山地区火山岩型铀矿床成矿母岩判别的指示意义

我国华南广泛分布火山-侵入杂岩体,其中个别岩体中伴有火山岩型铀矿床的产出,因此如何区分含铀矿与不含铀矿岩体成为矿床学界关注的重要课题。本文以相山地区含铀火山-侵入岩以及周边不含铀矿侵入岩为例,开展锆石LA-ICP-MS U-Pb年龄和微量元素研究。结果显示含矿花岗斑岩的形成年龄为133.7±1.6 Ma(云际),含矿碎斑熔岩的形成年龄为132.8±1.5 Ma(邹家山),不含矿花岗斑岩的年龄为134.9±1.3 Ma(七琴)和133.3±1.3 Ma(桃溪),其在误差范围内基本一致。含矿与不含矿岩体的锆石Ce^(4+)/Ce^(3+)比值由高到低依次为:邹家山22.12~68.75(平均值为45.61),云际19.02~43.48(平均值为27.64),七琴7.99~22.03(平均值为15.63),桃溪9.70~22.40(平均值为16.19)。锆石Ti含量温度计结果显示含矿岩体锆石的结晶温度比不含矿岩体的锆石结晶温度相对更高。结合晶格应变模型和锆石Ti温度计,获得前者的绝对氧逸度亦高于后者。本研究发现相山地区含矿火山-侵入岩体中锆石的Ce^(4+)/Ce^(3+)比值普遍大于22,笔者提出锆石氧逸度可以作为判别火山-侵入岩体是否含矿的一个可能指标。此外,含矿与不含矿岩体中全岩铀含量的高低与氧逸度呈明显的正相关,我们推断含矿岩体具有较高的氧逸度可能指示了其岩体母岩浆相应地具有更高的铀含量。综合前人的研究资料,笔者发现含铀岩体的氧逸度明显低于斑岩型铜-钼矿,但与花岗岩型钨矿以及火山岩型银-铅-锌矿类似。因此,氧逸度的相对高低对铜-钼、钨-钼、铀及银-铅-锌赋矿岩体的差异性成矿有明显制约作用,可能还间接反映了地幔物质贡献比例的多少。

脉搏血氧仪校准方法的研究

本方法适用于光电式的脉搏血氧仪(计)、脉搏血氧饱和度监护仪以及多参数监护仪中脉搏血氧监护部分的校准。在脉搏血氧仪质量控制方面,国家并没有专门的计量标准,各地依据当地的实际情况出台了地方标准,但是均没有关于光吸收比率拟合曲线误差的测量。本文主要介绍了脉搏血氧仪的组成和用途,针对目前临床在用设备,研究了脉搏血氧仪的校准方法,增加了光吸收比率拟合曲线示值误差项目,并对该校准方法进行了验证实验。此研究的目的是为开展相应的质量控制工作提供技术依据,希望通过质量控制确保脉搏血氧仪设备良好运行,有效保障医疗安全。

A^(2)/O+反硝化深床滤池在城镇污水处理厂深度经济脱氮的运行优化

脱氮是当前城镇污水处理的重点,其中A^(2)/O+反硝化滤池工艺是生活污水处理主流工艺,四川省岷江流域某城镇污水处理厂通过优化进水流量分配比、调节溶解氧和内回流比、碳源筛选等工艺试验,综合考察了工艺调控措施对系统脱氮效能的提升以及脱氮成本的经济化控制。结果表明,A^(2)/O池进水100%进入厌氧区、内回流比200%、A^(2)/O池末端溶解氧控制在1.5 mg/L、反硝化深床滤池投加液体复合碳源,在有效深度脱氮的同时节约运行费用,总氮指标满足岷沱江标准,脱氮费用降低0.37元/m^(3)。

氧气/燃料比对超音速火焰喷涂WC-Ni涂层抗冲击性能的影响

目的研究超音速火焰喷涂工艺参数对WC-12Ni硬质合金涂层抗冲击性能的影响。方法依据氧气/燃料比(λO/F)调节工艺参数,以λO/F=1.1为基准点,分别固定氧气流量811 L/min、降低煤油流量,或者固定煤油流量22.7 L/h、增大氧气流量,均使λO/F增至1.2和1.3,制备了5组涂层,分析涂层组织及力学性质的变化规律,研究柱-面接触大载荷冲击下的涂层抗冲击行为。结果λO/F对涂层组织及力学性质的影响并非已报道的单调变化规律。固定氧气流量、降低煤油流量使λO/F由1.1增至1.3时,涂层孔隙率由0.91%增至1.24%,硬度和弹性模量分别由10.1、344.0 GPa降至8.6、313.9 GPa;冲击坑体积由2.1×10^(-3)增至3.3×10^(-3)mm^(3),且损伤微观特征由WC颗粒剥落向涂层开裂发展。当固定煤油流量、增加氧气流量使λO/F由1.1增至1.3时,孔隙率降至0.85%,硬度和弹性模量分别增至10.8、382.5 GPa,冲击坑体积增至2.6×10^(-3)mm^(3),直到λO/F=1.3时涂层表面开始出现裂纹。结合涂层硬度和弹性模量分析结果可知,在H3/E2≤8.4 MPa时,涂层发生开裂损伤,裂纹长度随着H3/E2的增加而减小。在H3/E2>8.4 MPa时,涂层损伤以WC颗粒剥落为主,且随着H3/E2的增加而减轻。高H3/E2可提高涂层的抗冲击性能,当H3/E2由6.4 MPa增至8.7 MPa时,坑体积和WC剥落程度分别降低了36%、35%。结论超音速火焰喷涂WC-Ni涂层的H3/E2定量表征了其抵抗塑性变形和开裂的能力,决定了涂层的抗冲击性能。