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鞍钢炼钢生铁硫差产生的原因及对策
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作者 秦悦 孙彬 《鞍钢技术》 CAS 2002年第6期14-16,20,共4页
炼钢生铁硫差产生的原因比较复杂。通过研究分析产生硫差的几个主要因素 ,总结出鞍钢在现有生产条件下的硫差合理范围 ,并针对问题产生的原因 。
关键词 炼钢生产铁 硫差 高炉 炼铁
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MgS+1.5%ZrS_2固体电解质硫浓差电池的实验研究 被引量:4
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作者 于景坤 刘涛 陈敏 《金属学报》 SCIE EI CAS CSCD 北大核心 2005年第12期1285-1288,共4页
以金属和升华硫为原料,利用温度梯度法合成硫化物;并用合成的MgS+1.5%ZRS2作为固体电解质,以Mo+MoS2 作为参比极研制了硫浓差电池.在1623 K利用该电池对碳饱和铁水(氧的活度α[O]≤ 2×10-6)中的硫含量进行了测定.进 一步优化... 以金属和升华硫为原料,利用温度梯度法合成硫化物;并用合成的MgS+1.5%ZRS2作为固体电解质,以Mo+MoS2 作为参比极研制了硫浓差电池.在1623 K利用该电池对碳饱和铁水(氧的活度α[O]≤ 2×10-6)中的硫含量进行了测定.进 一步优化了硫浓差电池的结构,解决了电解质管的炸裂和漏气问题,同时采用特殊工艺抑制了硫化物水化.结果表明,该硫浓差电 池的电动势信号稳定,重现性好且持续时间长. 展开更多
关键词 电池 固体电解质 参比极 化物 温度梯度法
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改良差示酚硫法测定红芪粗多糖的方法研究 被引量:16
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作者 魏舒畅 王继龙 +2 位作者 李昶 金辉 章武 《中成药》 CAS CSCD 北大核心 2013年第3期634-636,共3页
目的建立以葡萄糖为对照品,定量测定红芪粗多糖样品中多糖量的方法。方法通过研究红芪多糖中几种单糖的精确比例,采用改良差示酚硫法,比较以葡萄糖为对照品和以5种单糖组成的混合物为对照品测定结果间的关系,获得校正方程,建立直接以葡... 目的建立以葡萄糖为对照品,定量测定红芪粗多糖样品中多糖量的方法。方法通过研究红芪多糖中几种单糖的精确比例,采用改良差示酚硫法,比较以葡萄糖为对照品和以5种单糖组成的混合物为对照品测定结果间的关系,获得校正方程,建立直接以葡萄糖为对照品的红芪粗多糖的定量测定方法。结果组成红芪多糖的鼠李糖、木糖、阿拉伯糖、葡萄糖和半乳糖比例为4.95∶12.52∶24.68∶51.30∶6.55。葡萄糖标准曲线ΔA=6.6×10-3C+0.085 7,线性范围25~250μg/mL,r=0.999 8;校正方程Y=1.236 1X+0.019 1,线性范围85.4~206.7μg/mL,r=1.000;平均回收率为104.9%,RSD为2.5%。结论该方法操作简便、准确可靠,可直接用于红芪粗多糖的定量测定。 展开更多
关键词 红芪粗多糖 定量测定 改良示酚
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改良差示酚硫法测定红松松塔多糖的含量 被引量:6
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作者 王薇薇 张曜武 +1 位作者 龙堂荣 魏焕焕 《西北药学杂志》 CAS 2013年第4期340-342,共3页
目的建立红松松塔多糖含量测定方法。方法采用改良差示酚硫法测定红松松塔多糖含量。结果多糖溶液沸水浴30min水解完全,显色液预配,用量为5.0mL;显色后的待测液在2h内稳定;测定波长λmax=490nm;线性范围为3.57~21.42μg·mL-1,r=0.... 目的建立红松松塔多糖含量测定方法。方法采用改良差示酚硫法测定红松松塔多糖含量。结果多糖溶液沸水浴30min水解完全,显色液预配,用量为5.0mL;显色后的待测液在2h内稳定;测定波长λmax=490nm;线性范围为3.57~21.42μg·mL-1,r=0.999;回收率为98.3%,RSD为1.06%。结论该方法可用于红松松塔多糖的含量测定,含杂质的样品不必进行繁琐的预分离纯化,方法简便、准确,重复性好。 展开更多
关键词 多糖 苯酚酸法 改良示酚 含量测定 红松松塔
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差式酚硫法的建立及对五子衍宗颗粒剂中多糖测定比较研究 被引量:10
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作者 贺福元 罗杰英 +2 位作者 刘平安 邓凯文 刘文龙 《中医药导报》 2006年第1期2-5,共4页
目的:建立差式酚硫法并与酚硫法、蒽酮法、咔唑法一起比较测定五子衍宗颗粒剂中总多糖的含量;方法:先在酚硫法的基础上创立差示酚硫法,再与酚硫法、蒽酮法、咔唑法一并测定;结果:差式酚硫法的测定条件:样品可直接用未精制多糖水提液;反... 目的:建立差式酚硫法并与酚硫法、蒽酮法、咔唑法一起比较测定五子衍宗颗粒剂中总多糖的含量;方法:先在酚硫法的基础上创立差示酚硫法,再与酚硫法、蒽酮法、咔唑法一并测定;结果:差式酚硫法的测定条件:样品可直接用未精制多糖水提液;反应在4.5h以内完成;测定波长λm ax=490nm;线性范围在3.56μg^35.6μg;相关系数r=0.996;RSD=2.85%;回收率为99.9%。用差式酚硫法、酚硫法、蒽酮法、咔唑法分别测得五子衍宗颗粒剂中多糖为(13.1±0.458)%,(9.97±0.416)%,(10.3±0.422)%,(10.3±0.610)%,经t检验,四法测定五子衍宗颗粒剂中多糖含量有显著性差异;结论:差式酚硫法可用于中药制剂多糖的含量测定,多糖可直接采未精制样品,不必分离纯化,因此该法操作简捷、快速、精密度高。 展开更多
关键词 式酚 五子衍宗颗粒剂 多糖 含量分析
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枸杞多糖改良差示酚硫法测定及其木瓜蛋白酶辅助提取工艺研究 被引量:3
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作者 高建德 师婷婷 +1 位作者 范凌云 刘雄 《西部中医药》 2018年第9期56-60,共5页
目的:通过改良差示酚硫法测定枸杞多糖含量,优化木瓜蛋白酶辅助提取枸杞多糖的工艺。方法:在改良差示酚硫法测定枸杞多糖含量基础上,采用均匀设计法,以枸杞多糖提取率为指标,木瓜蛋白酶用量、pH、酶解时间和酶解温度为考察因素,每个因素... 目的:通过改良差示酚硫法测定枸杞多糖含量,优化木瓜蛋白酶辅助提取枸杞多糖的工艺。方法:在改良差示酚硫法测定枸杞多糖含量基础上,采用均匀设计法,以枸杞多糖提取率为指标,木瓜蛋白酶用量、pH、酶解时间和酶解温度为考察因素,每个因素7个水平,建立4因素7水平的均匀设计试验,应用SPSS19. 0软件对数据进行多元回归分析,并通过相对黏度和体外抗氧化性对优化工艺下的枸杞提取物与传统提取比较。结果:改良差示酚硫法测定枸杞多糖条件为:测定波长λmax=484 nm,相关系数R^2=0. 9994,重复性RSD=2. 45%,回收率为98. 76%;木瓜蛋白酶辅助提取枸杞多糖的最佳工艺条件为:酶用量为0. 2%,pH为4. 2,温度为40℃,酶解时间为1. 0小时。木瓜蛋白酶辅助提取后,相同条件下枸杞提取物相对黏度,体外抗氧化性高于传统提取方法。结论:改良差示酚硫法可用于枸杞多糖含量测定,木瓜蛋白酶辅助提取枸杞多糖可提高其中多糖的利用率。 展开更多
关键词 改良示酚 枸杞多糖 木瓜蛋白酶 提取工艺
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硫氰酸盐差示光度法测定钼钒铝合金中的钼含量
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作者 沙莎 席洋洋 刘月菊 《当代化工研究》 2020年第9期153-154,共2页
硫氰酸盐差示光度法测定高含量钼铁合金在测定同时含高含量钼和钒的合金钢时,有显色不稳定及钒显色干扰测定的问题。结合实际情况,针对此合金产品:钼钒铝(40:40:20)中钼含量的检测,利用基体匹配方式,采用差示光度法对该产品中的钼含量... 硫氰酸盐差示光度法测定高含量钼铁合金在测定同时含高含量钼和钒的合金钢时,有显色不稳定及钒显色干扰测定的问题。结合实际情况,针对此合金产品:钼钒铝(40:40:20)中钼含量的检测,利用基体匹配方式,采用差示光度法对该产品中的钼含量进行测定,得到了理想的结果。 展开更多
关键词 氰酸盐示光度法 钼钒铝合金
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锅炉烟气脱硫脱硝系统运行问题及处理措施 被引量:5
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作者 门小勇 《中国新技术新产品》 2016年第9期58-59,共2页
甲醇厂CFB锅炉烟气脱硫脱硝系统改造投运后,脱硫系统出现硫酸铵浆液结晶差、脱硫塔循环喷头堵塞、液氨消耗大、硫酸铵输送玻璃钢管线断裂频繁等问题,SNCR脱硝系统出现了氨水浓度低、NOX指标不合格等问题。以上问题经过技术攻关和设备改... 甲醇厂CFB锅炉烟气脱硫脱硝系统改造投运后,脱硫系统出现硫酸铵浆液结晶差、脱硫塔循环喷头堵塞、液氨消耗大、硫酸铵输送玻璃钢管线断裂频繁等问题,SNCR脱硝系统出现了氨水浓度低、NOX指标不合格等问题。以上问题经过技术攻关和设备改造,逐步予以解决并优化了脱硫脱硝运行工况。 展开更多
关键词 氨-肥法脱工艺 SNCR脱硝工艺 铵结晶 液氨消耗大
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差示分光光度法测定Cu30W70钨铜合金中钨的含量 被引量:1
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作者 张桂竹 《中国无机分析化学》 CAS 2014年第2期58-61,共4页
采用传统的湿化学差示分光光度分析方法,研究了广泛用于军工、高压开关、电火花电极、电子封装的新型材料钨铜合金中钨含量的定量分析方法。由于该材料的耐腐蚀性,试样溶解是关键,实验表明采用盐酸+硝酸(9+1)、硫酸+磷酸(1+3... 采用传统的湿化学差示分光光度分析方法,研究了广泛用于军工、高压开关、电火花电极、电子封装的新型材料钨铜合金中钨含量的定量分析方法。由于该材料的耐腐蚀性,试样溶解是关键,实验表明采用盐酸+硝酸(9+1)、硫酸+磷酸(1+3)混合酸低温加热溶解,测定时加入草酸胺掩蔽铜的干扰,用硫氰酸胺显色。以Cu30W70为例用40%的钨为参比,配制一系列标准溶液制作工作曲线,钨含量在5-10μg/mL内服从比耳定律,方法的相对标准偏差(RSD)为1.6%,加标回收率为101.6%,适用于含钨45%以上的钨铜合金中钨的测定。 展开更多
关键词 分析化学 钨量测定 氰酸胺示分光光度法 钨铜合金
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焦炉气制甲醇装置常温氧化锌脱硫剂使用问题分析
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作者 刘保林 姚丽江 +1 位作者 路嘉 成庆 《中氮肥》 CAS 2023年第3期53-55,共3页
河北金牛旭阳化工有限公司200 kt/a焦炉气制甲醇装置甲烷转化系统后设有2台常温氧化锌脱硫槽(一开一备),自2009年6月投产以来一直存在新更换的脱硫剂投用约半个月即出现硫穿透而致出口工艺气总硫含量超标等问题。基于2019—2020年10槽... 河北金牛旭阳化工有限公司200 kt/a焦炉气制甲醇装置甲烷转化系统后设有2台常温氧化锌脱硫槽(一开一备),自2009年6月投产以来一直存在新更换的脱硫剂投用约半个月即出现硫穿透而致出口工艺气总硫含量超标等问题。基于2019—2020年10槽常温氧化锌脱硫剂使用情况进行分析,认为是系统流程设计存在缺陷(工艺气中的饱和水冷凝析出严重影响脱硫剂的正常使用)及设计空速偏大所致。2022年8月甲醇装置大修期间实施增设1台列管换热器(加热脱硫槽进口气)及2022年初增加约8 m^(3)的脱硫剂装填量(降低空速)等优化改进后,确保了脱硫效果,常温氧化锌脱硫剂的有效使用时间大大延长,降低了脱硫成本。 展开更多
关键词 焦炉气制甲醇装置 常温氧化锌脱 效果 原因分析 工艺流程不合理 设计空速偏大 优化改进
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UV_Ⅱ型硫回收装置尾气H_2S/SO_2分析仪的研制与应用 被引量:1
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作者 庄际 袁文章 +2 位作者 陈怡 张新华 陈力钧 《化工自动化及仪表》 CAS 北大核心 2010年第6期65-67,共3页
介绍基于朗伯-比尔定律开发、主要应用于"克劳斯"硫回收装置的UV_Ⅱ型硫回收装置尾气H2S/SO2分析仪。该仪器替代价格昂贵的进口仪表,已成功应用于扬子石化的硫回收装置。
关键词 H2S/SO2分析仪 S7-200 温”除 “克劳斯”回收
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洛阳分公司S Zorb装置运行分析
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作者 王明东 《炼油技术与工程》 CAS 2016年第11期11-14,共4页
S Zorb装置是生产符合国Ⅳ甚至国Ⅴ标准汽油的重要生产装置。中国石油化工股份有限公司洛阳分公司S Zorb装置自2013年10月投入运行以来,通过生产优化,采用"小循环量、大硫差"的运行模式,适应了装置生产的需要,确保了装置运行... S Zorb装置是生产符合国Ⅳ甚至国Ⅴ标准汽油的重要生产装置。中国石油化工股份有限公司洛阳分公司S Zorb装置自2013年10月投入运行以来,通过生产优化,采用"小循环量、大硫差"的运行模式,适应了装置生产的需要,确保了装置运行平稳。但在应对公司顺序加工,原料性质变化较大的生产问题时,出现了催化汽油硫含量突然上升,产品质量无法满足要求等问题,通过采取措施,解决了吸附剂的流化问题,确保了公司汽油的顺利出厂。对装置运行中的问题进行了分析,提出了解决方案,保证汽油产品合格。 展开更多
关键词 S Zorb装置 吸附脱 硫差 吸附剂
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Apparent activation energy for spontaneous combustion of sulfide concentrates in storage yard 被引量:5
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作者 阳富强 吴超 +1 位作者 崔燕 陆广 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2011年第2期395-401,共7页
In order to evaluate the spontaneous combustion hazard of sulfide concentrates in storage, three different kinds of sulfide concentrates (sulfur-rich sulfide concentrate, iron sulfide concentrate and copper sulfide c... In order to evaluate the spontaneous combustion hazard of sulfide concentrates in storage, three different kinds of sulfide concentrates (sulfur-rich sulfide concentrate, iron sulfide concentrate and copper sulfide concentrate) were obtained from a storage yard in Dongguashan Copper Mine, China. The reaction processes at different heating rates of 5, 10, 15, 20, and 25 ℃/min in air flow from ambient temperature to 1 000 ℃ were studied by TG-DTG-DSC analysis. By the peak temperatures of DTG curves, the whole reaction process for each sample was divided into different stages, and the corresponding apparent activation energies were calculated by the Ozawa-Flynn-Wall method. It is found that the reaction process of each sample is considerably complex; the apparent activation energy values change from 36 to 160 kJ/mol in different temperature ranges; sulfur-rich sulfide and iron sulfide concentrates have lower apparent activation energy than copper sulfide concentrate below 150 ℃; so they are more inclined to cause spontaneous combustion at ambient temperature. 展开更多
关键词 apparent activation energy sulfide concentrates spontaneous combustion thermogravimetry (TG) analysis differential scanning calorimetry (DSC)
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Effects of High Hydrostatic Pressure Treatment on Physicochemical Characteristics of Sea Cucumber 被引量:2
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作者 Yuanjing Xia Zhijun Liu Zhiyi Li 《Journal of Food Science and Engineering》 2012年第4期227-238,共12页
The effects of high hydrostatic pressure (HHP) treatment on sea cucumber qualities, such as shelf-life, autoenzyme, total volatile basic nitrogen (TVB-N), mucopolysaccha ride and protein, were investigated experim... The effects of high hydrostatic pressure (HHP) treatment on sea cucumber qualities, such as shelf-life, autoenzyme, total volatile basic nitrogen (TVB-N), mucopolysaccha ride and protein, were investigated experimentally. The shelf-life of sea cucumber was greatly prolonged by HHP treatment. High pressure treatment of sea cucumber significantly reduced the activity of autoenzyme at 550 MPa. The TVB-N content was 8.4 mg/100 g in the HHP-treated samples after 38 days' storage at 4 ~C, while it had already reached 11.2 mg/100 g in the untreated ones after 5 days' storage under the same condition. The relative mucopolysaccharide content of the HHP-treated samples was 94.3%, while that of the heat-treated ones was only 35.5%. The sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), Differential scanning calorimetric (DSC), ANS fluorescence probe method and fourier-transform infrared (FTIR) spectroscopy results indicated some changes in protein subunits, denaturation, surface hydrophobicity and secondary structure of sea cucumber protein. This study has provided complementary information of pressure-induced structural changes on both the molecular and the sub-molecular level of sea cucumber protein. 展开更多
关键词 High hydrostatic pressure sea cucumber shelf-life autoenzyme.
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Phenotypic and genetic characterization of a novel strain of Acidithiobacillus ferrooxidans(AF2) 被引量:1
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作者 刘倩 周洪波 +2 位作者 杨波 敖敬群 陈新华 《Journal of Central South University》 SCIE EI CAS 2011年第2期386-391,共6页
A comparative study on the phenotypic and genetic characteristics among Acidithiobacillus ferrooxidans (AF2), a typic strain ATCC23270 and a previously isolated strain AF3 was performed. AF2 can use ferrous ion (F... A comparative study on the phenotypic and genetic characteristics among Acidithiobacillus ferrooxidans (AF2), a typic strain ATCC23270 and a previously isolated strain AF3 was performed. AF2 can use ferrous ion (Fe^2+) or elemental sulfur (S^0) as sole energy source, but oxidizes So more effectively than Fe^2+, which is different from ATCC23270 and AF3. The G+C content of AF2 is 51.8% (molar fraction), however, ATCC23270 and AF3 strains have G+C content of 63.7% and 64.8% (molar fraction), respectively. The DNA-DNA hybridization results show that AF2 has 41.53% and 52.38% genome similarity to ATCC 23270 and AF3, respectively, but AF3 has a high genome similarity of 89.86% to ATCC 23270 strain. Rusticyanin (rus) and subunit III of aa3-type cytochrome oxidase (coxC) genes are not detected in AF2, but Fe^2+ oxidase (iro) gene can be detected. To understand the genomic organization of iro gene, a cosmid library of AF2 genome was constructed and iro gene-containing clone was screened. The sequencing result shows that although the nucleotide sequence of iro gene in AF2 is completely identical to that of ATCC 23270 strain, its genomic organization is different from that of ATCC 23270. In AF2, iro is located at downstream ofpurA gene, while it is located at downstream ofpetC-2 gene in ATCC 23270 strain. These results indicate that AF2 is a novel strain ofA. ferrooxidans, and that phenotypic differences among the strains ofA. ferrooxidans are closely correlated with their genetic polymorphisms. 展开更多
关键词 Aeidithiobacillusferrooxidans phenotypic and genetic characterization Iro gene cosmid library iron respiratory chain
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Solubilities of 1-Methyl-3-(3-sulfopropyl)-imidazolium Hydrogen Sulfate in Selected Solvents 被引量:5
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作者 CAI Shuangfei WANG Lisheng YAN Guoqing LI Yi 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2010年第6期1008-1012,共5页
Ionic liquid 1-methyl-3-(3-sulfopropyl) -imidazolium hydrogen sulfate([C3SO3HMIM][HSO4]) was synthesized and characterized by infrared spectroscopy(IR) ,nuclear magnetic resonance(1H and 13C NMR) and ultraviolet-visib... Ionic liquid 1-methyl-3-(3-sulfopropyl) -imidazolium hydrogen sulfate([C3SO3HMIM][HSO4]) was synthesized and characterized by infrared spectroscopy(IR) ,nuclear magnetic resonance(1H and 13C NMR) and ultraviolet-visible(UV-Vis) spectra. Its thermal stability was also examined by thermogravimetric analysis(TGA) and a differential scanning calorimeter(DSC) . The mole fraction solubilities of [C3SO3HMIM][HSO4]) in 12 selected solvents(n-pentane,n-hexane,n-heptane,benzene,toluene,ethylbenzene,acetone,2-butanone,3-methyl-2-butanone,tetrahydrofuran,ethyl acetate and dichloromethane) in the temperature range from 289.15 to 363.15 K were meas-ured using a static analytical method and correlated with an empirical equation. 展开更多
关键词 Brφnsted acidic ionic liquid SOLUBILITY organic solvent static analytical method
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Partial least squares regression for predicting economic loss of vegetables caused by acid rain 被引量:2
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作者 王菊 房春生 《Journal of Chongqing University》 CAS 2009年第1期10-16,共7页
To predict the economic loss of crops caused by acid rain,we used partial least squares(PLS) regression to build a model of single dependent variable -the economic loss calculated with the decrease in yield related to... To predict the economic loss of crops caused by acid rain,we used partial least squares(PLS) regression to build a model of single dependent variable -the economic loss calculated with the decrease in yield related to the pH value and levels of Ca2+,NH4+,Na+,K+,Mg2+,SO42-,NO3-,and Cl-in acid rain. We selected vegetables which were sensitive to acid rain as the sample crops,and collected 12 groups of data,of which 8 groups were used for modeling and 4 groups for testing. Using the cross validation method to evaluate the performace of this prediction model indicates that the optimum number of principal components was 3,determined by the minimum of prediction residual error sum of squares,and the prediction error of the regression equation ranges from -2.25% to 4.32%. The model predicted that the economic loss of vegetables from acid rain is negatively corrrelated to pH and the concentrations of NH4+,SO42-,NO3-,and Cl-in the rain,and positively correlated to the concentrations of Ca2+,Na+,K+ and Mg2+. The precision of the model may be improved if the non-linearity of original data is addressed. 展开更多
关键词 acid rain partial least-squares regression economic loss dose-response model
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Differential expression of genes encoding sulfur metabolism-related periplasmic proteins of Acidithiobacillus ferrooxidans ATCC 23270
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作者 夏金兰 张瑞永 +4 位作者 张倩 武顺 张成桂 聂珍媛 邱冠周 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2010年第12期2366-2370,共5页
Reverse-transcription qualitative PCR(RT-qPCR)was used to analyze the changes in transcription levels of the sulfur metabolism-related periplasmic protein genes of Acidithiobacillus ferrooxidans ATCC 23270 grown on su... Reverse-transcription qualitative PCR(RT-qPCR)was used to analyze the changes in transcription levels of the sulfur metabolism-related periplasmic protein genes of Acidithiobacillus ferrooxidans ATCC 23270 grown on sulfur or ferrous.Seven periplasmic proteins with apparently higher abundance grown on elemental sulfur than on ferrous sulfate were identified by matrix-assisted laser desorption ionization time-of-flight mass spectrometry(MALDI-TOF-MS).Expression analysis of the corresponding genes by RT-qPCR shows that the constitutive expression of all those genes are more up-regulated grown on sulfur than those grown on ferrous(>10 folder).Study on the corresponding genes of the identified periplasmic proteins by RT-qPCR confirmed the results of two-dimensioned gel electrophoresis,indicating they may be related with sulfur metabolism in A.ferrooxidans. 展开更多
关键词 Acidithiobacillus ferrooxidans RT-QPCR periplasmic proteins
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Analysis of H_2S Tolerance of Pd-Cu Alloy Hydrogen Separation Membranes
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作者 高会元 王岭 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2014年第5期503-508,共6页
The presence of a limited amount of H2S in H2-rich feed adversely affects the Pd-Cu membrane permeation performance due to the sulphidization of the membrane surface. A theoretical model was proposed to predict the S-... The presence of a limited amount of H2S in H2-rich feed adversely affects the Pd-Cu membrane permeation performance due to the sulphidization of the membrane surface. A theoretical model was proposed to predict the S-tolerant performance of the Pd-Cu membranes in presence of H2S under the industrial water-gas-shift(WGS) reaction conditions. The ideas of surface coverage and competitive adsorption thermodynamics of H2S and H2 on Pd-Cu surface were introduced in the model. The surface sulphidization of the Pd-Cu membranes mainly depended on the pressure ratio of H2S to H2, temperature and S-adsorbed surface coverage, i.e., the occurrence of sulphidization on the surface was not directly related with the bulk compositions and structures [body centered cubic and face centered cubic(bcc or fcc)] of Pd-Cu alloy membranes because of the surface segregation phenomena. The resulting equilibrium equations for the H2S adsorption/sulphidization reactions were solved to calculate the pressure ratio of H2S to H2 over a wide range of temperatures. A validation of the model was performed through a comparison between lots of literature data and the model calculations over a rather broad range of operating conditions. An extremely good agreement was obtained in the different cases, and thus, the model can serve to guide the development of S-resistant Pd alloy membrane materials for hydrogen separation. 展开更多
关键词 surtace coverage Pd-Cu alloy membranes H2S tolerance theoretical model hydrogen separation
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Estimation of Partition Coefficients of Fe-S Protein Models: Se Substitutions in Fe4S4Cysn
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作者 Francisco Torrens Gloria Castellano 《Journal of Chemistry and Chemical Engineering》 2012年第10期867-877,共11页
The SCAP method allows a semiquantitative estimation of the partitioning of many solutes between numerous pairs of solvents. The organic solvent-water partition coefficients P are calculated. For FeaS4Cysn, the organi... The SCAP method allows a semiquantitative estimation of the partitioning of many solutes between numerous pairs of solvents. The organic solvent-water partition coefficients P are calculated. For FeaS4Cysn, the organic solvent-water partition coefficients for l-octanol Po, cyclohexane Pch and chloroform Pcf decay 4.46, 6.25 and 4.60 log units per Cys, respectively. The Po is of the same order of magnitude as CDHI (conformationally dependent hydrophobic index) calculations and Pch-cf as computations performed with a method by Leo and Hansch. The logPo-ch-cf mean relative errors are 17%, 25% and-17%, which represent mean and unsigned relative errors of -3% and 20%. On varying the number of Cys, the structures show hydrophobic moments indicative of amphipathic compounds. For Se substitutions in Fe4SeaCys,, Po-ch-cf drop 4.52, 6.30 and 4.66 exponents per Cys. With the reference calculations, Po-ch-cf decay 4.03, 4.80 and 5.76 exponents per Cys. For FeaS4 mSemCys4, the calculated similar partition coefficients and hydrophobic moments, and lower distance in dendrogram suggest a role of Fe-Se clusters in physiological processes. The analysis is extended to lysozyme and its secondary structures. 展开更多
关键词 Solvation parameter model partition coefficient hydrophobic moment iron-sulphur protein mixed-valence non-integeroxidation number.
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