In this paper, pyrolysis of Indonesian oil sands （lOS） was investigated by two different heating methods to develop a better understanding of the microwave-assisted pyrolysis. Thermogravimetric analysis was conducte...In this paper, pyrolysis of Indonesian oil sands （lOS） was investigated by two different heating methods to develop a better understanding of the microwave-assisted pyrolysis. Thermogravimetric analysis was conducted to study the thermal decomposition behaviors of lOS, showing that 550 ℃ might be the pyrolysis final temperature. A explanation of the heat-mass transfer process was presented to demonstrate the influence of mi- crowave-assisted pyrolysis on the liquid product distribution. The heat-mass transfer model was also useful to explain the increase of liquid product yield and heavy component content at the same heating rate by two differ- ent heating methods. Experiments were carried out using a fixed bed reactor with and without the microwave irradiation. The results showed that liquid product yield was increased during microwave induced pyrolysis, while the formation of gas and solid residue was reduced in comparison with the conventional pyrolysis. Moreover, the liquid product characterization by elemental analysis and GC-MS indicated the significant effect on the liquid chemical composition by microwave irradiation. High polarity substances （ε 〉 10 at 25 ℃）, such as oxy- organics were increased, while relatively low polarity substances （ε 〈 2 at 25℃）, such as aliphatic hydrocarbons were decreased, suggesting that microwave enhanced the relative volatility of high polarity substances. The yield improvement and compositional variations in the liquid product promoted by the microwave-assisted pyrolysis deserve the further exploitation in the future,展开更多
The contents of eight trace elements(Mn, Cr, Pb, As, Se, Zn, Cd, Hg) in raw coal, bottom ash and fly ash were measured in a 220 t/h pulverized coal boiler. Factors affecting distribution of trace elements were investi...The contents of eight trace elements(Mn, Cr, Pb, As, Se, Zn, Cd, Hg) in raw coal, bottom ash and fly ash were measured in a 220 t/h pulverized coal boiler. Factors affecting distribution of trace elements were investigated, including fly ash diameter, furnace temperature, oxygen content and trace elements' characters. One coefficient of Meij was also improved to more directly show element enrichment in combustion products. These elements may be classified into three groups according to their distribution: Group 1: Hg, which is very volatile. Group 2: Pb, Zn, Cd, which are partially volatile. Group 3: Mn, which is hardly volatile. Se may be located between groups 1 and 2 Cr has properties of both group 1 and 3 In addition, the smaller diameter of fly ash, the more relative enrichment of trace elements(except Mn). The fly ash showed different adsorption mechanisms of trace elements and the volatilization of trace elements rises with furnace temperature. Relative enrichments of trace elements(except Mn and Cr) in fly ash are larger than that in bottom ash. Low oxygen content can not always improve the volatilization of trace elements. Pb is easier to form chloride than Cd during coal combustion. Trace elements should be classified in accordance with factors.展开更多
为探究丁酸梭菌对小尾寒羊宰后成熟过程中挥发性风味物质的影响及其可能机制,以6月龄小尾寒羊为研究对象,取其背最长肌进行宰后成熟(4℃),然后分别在第0、1、2、3、4、5天对羊肉中的挥发性风味物质和腺苷酸活化蛋白激酶(adenosine monop...为探究丁酸梭菌对小尾寒羊宰后成熟过程中挥发性风味物质的影响及其可能机制,以6月龄小尾寒羊为研究对象,取其背最长肌进行宰后成熟(4℃),然后分别在第0、1、2、3、4、5天对羊肉中的挥发性风味物质和腺苷酸活化蛋白激酶(adenosine monophosphate activated protein kinase,AMPK)、乙酰辅酶A羧化酶(acetyl CoA carboxylase,ACC)和肉毒碱脂酰转移酶1(carnitine palmitoyltransferase,CPT1)等脂肪代谢相关酶活性进行测定。电子鼻测定结果显示,丁酸梭菌组小尾寒羊肉中的烷类、氢过氧化物和氮氧化合物的含量更加丰富;结合气相色谱-质谱联用技术测定结果可知,丁酸梭菌组小尾寒羊肉中醛、醇及酮类化合物的种类较为丰富,而脂肪氧化产物如辛醛、壬醛、癸醛、庚醛的含量均明显降低;利用相对气味活度值法筛选了宰后成熟过程中两组小尾寒羊肉中共有的关键风味物质,包括辛醛、壬醛、反-2-癸烯醛和1-辛烯-3-醇,其中癸醛对羊肉风味的贡献最大。与对照组相比,丁酸梭菌组小尾寒羊肉中AMPK和CPT1的含量在宰后成熟过程中均显著降低(P<0.05),而丁酸梭菌组小尾寒羊肉中ACC含量在宰后成熟第0、1、3、5天显著高于对照组(P<0.05);相关性分析结果表明,AMPK和CPT1与壬醛均呈极显著正相关(P<0.001),而ACC与壬醛和癸醛呈极显著负相关(P<0.001)。综上,日粮添加丁酸梭菌可能通过调控AMPK-ACC-CPT1通路进而影响小尾寒羊宰后成熟过程中的挥发性风味物质。展开更多
Due to the majority of time people spent indoors,indoor air quality is not only critical to people’s health,comfort,but can also significantly influence occupants perception on indoor environment.Air quality is close...Due to the majority of time people spent indoors,indoor air quality is not only critical to people’s health,comfort,but can also significantly influence occupants perception on indoor environment.Air quality is closely related to many factors including thermal parameters,pollutant concentrations,and ventilation performance.However,the current building indoor air quality evaluation method is based the objective measurement of indoor parameters,without considering occupants’subjective perception.This paper is aimed at summarizing a profound review on the PAQ evaluation method.Comparisons among various PAQ evaluating methods with advantages,similarities and differences were conducted.Analysis of literatures about indoor air quality in Chinese residential buildings field is also summarized,and discussion on the subjective influence of temperature and relative humidity,venti-lation performance,volatile organic compounds(VOCs)concentration,and particulate matters on perceived air quality is carried out.展开更多
Vapor wall losses can affect the yields of secondary organic aerosol.The effects of surfaceto-volume(S/V)ratio and relative humidity(RH)on the vapor-wall interactions were investigated in this study.The oxygenated vol...Vapor wall losses can affect the yields of secondary organic aerosol.The effects of surfaceto-volume(S/V)ratio and relative humidity(RH)on the vapor-wall interactions were investigated in this study.The oxygenated volatile organic compounds(OVOCs)were generated from toluene-H_(2)O_(2)irradiations.The average gas to wall loss rate constant(k_(gw))of OVOCs in a 400 L reactor(S/V=7.5 m^(-1))is 2.47(2.41 under humid conditions)times higher than that in a 5000 L reactor(S/V=3.6 m-1)under dry conditions.In contrast,the average desorption rate constant(k_(wg))of OVOCs in 400 L reactor is only 1.37(1.20 under humid conditions)times higher than that in 5000 L reactor under dry conditions.It shows that increasing the S/V ratio can promote the wall losses of OVOCs.By contrast,the RH effect on k_(gw)is not prominent.The average k_(gw)value under humid conditions is almost the same as under dry conditions in the 400 L(5000 L)reactor.However,increasing RH can decrease the desorption rates.The average k_(wg)value under dry conditions is 1.45(1.27)times higher than that under humid conditions in the 400 L(5000 L)reactor.The high RH can increase the partitioning equilibrium timescales and enhance the wall losses of OVOCs.展开更多
基金Supported by the National Key Research and Development Program of China(2016YFB0301800)the partial support by The Royal Society International Exchange Award(IE161344)the State Scholarship Fund of China Scholarship Council(CSC)(201706255020)
文摘In this paper, pyrolysis of Indonesian oil sands （lOS） was investigated by two different heating methods to develop a better understanding of the microwave-assisted pyrolysis. Thermogravimetric analysis was conducted to study the thermal decomposition behaviors of lOS, showing that 550 ℃ might be the pyrolysis final temperature. A explanation of the heat-mass transfer process was presented to demonstrate the influence of mi- crowave-assisted pyrolysis on the liquid product distribution. The heat-mass transfer model was also useful to explain the increase of liquid product yield and heavy component content at the same heating rate by two differ- ent heating methods. Experiments were carried out using a fixed bed reactor with and without the microwave irradiation. The results showed that liquid product yield was increased during microwave induced pyrolysis, while the formation of gas and solid residue was reduced in comparison with the conventional pyrolysis. Moreover, the liquid product characterization by elemental analysis and GC-MS indicated the significant effect on the liquid chemical composition by microwave irradiation. High polarity substances （ε 〉 10 at 25 ℃）, such as oxy- organics were increased, while relatively low polarity substances （ε 〈 2 at 25℃）, such as aliphatic hydrocarbons were decreased, suggesting that microwave enhanced the relative volatility of high polarity substances. The yield improvement and compositional variations in the liquid product promoted by the microwave-assisted pyrolysis deserve the further exploitation in the future,
文摘The contents of eight trace elements(Mn, Cr, Pb, As, Se, Zn, Cd, Hg) in raw coal, bottom ash and fly ash were measured in a 220 t/h pulverized coal boiler. Factors affecting distribution of trace elements were investigated, including fly ash diameter, furnace temperature, oxygen content and trace elements' characters. One coefficient of Meij was also improved to more directly show element enrichment in combustion products. These elements may be classified into three groups according to their distribution: Group 1: Hg, which is very volatile. Group 2: Pb, Zn, Cd, which are partially volatile. Group 3: Mn, which is hardly volatile. Se may be located between groups 1 and 2 Cr has properties of both group 1 and 3 In addition, the smaller diameter of fly ash, the more relative enrichment of trace elements(except Mn). The fly ash showed different adsorption mechanisms of trace elements and the volatilization of trace elements rises with furnace temperature. Relative enrichments of trace elements(except Mn and Cr) in fly ash are larger than that in bottom ash. Low oxygen content can not always improve the volatilization of trace elements. Pb is easier to form chloride than Cd during coal combustion. Trace elements should be classified in accordance with factors.
文摘为探究丁酸梭菌对小尾寒羊宰后成熟过程中挥发性风味物质的影响及其可能机制,以6月龄小尾寒羊为研究对象,取其背最长肌进行宰后成熟(4℃),然后分别在第0、1、2、3、4、5天对羊肉中的挥发性风味物质和腺苷酸活化蛋白激酶(adenosine monophosphate activated protein kinase,AMPK)、乙酰辅酶A羧化酶(acetyl CoA carboxylase,ACC)和肉毒碱脂酰转移酶1(carnitine palmitoyltransferase,CPT1)等脂肪代谢相关酶活性进行测定。电子鼻测定结果显示,丁酸梭菌组小尾寒羊肉中的烷类、氢过氧化物和氮氧化合物的含量更加丰富;结合气相色谱-质谱联用技术测定结果可知,丁酸梭菌组小尾寒羊肉中醛、醇及酮类化合物的种类较为丰富,而脂肪氧化产物如辛醛、壬醛、癸醛、庚醛的含量均明显降低;利用相对气味活度值法筛选了宰后成熟过程中两组小尾寒羊肉中共有的关键风味物质,包括辛醛、壬醛、反-2-癸烯醛和1-辛烯-3-醇,其中癸醛对羊肉风味的贡献最大。与对照组相比,丁酸梭菌组小尾寒羊肉中AMPK和CPT1的含量在宰后成熟过程中均显著降低(P<0.05),而丁酸梭菌组小尾寒羊肉中ACC含量在宰后成熟第0、1、3、5天显著高于对照组(P<0.05);相关性分析结果表明,AMPK和CPT1与壬醛均呈极显著正相关(P<0.001),而ACC与壬醛和癸醛呈极显著负相关(P<0.001)。综上,日粮添加丁酸梭菌可能通过调控AMPK-ACC-CPT1通路进而影响小尾寒羊宰后成熟过程中的挥发性风味物质。
基金国家自然科学基金面上项目“金融高频大数据下的风险推断及其与多元标的衍生品定价和金融风险管理的交叉融合研究”(71871132)国家自然科学基金委重大研究计划重点项目“金融大数据统计推断理论与方法及应用研究”(91546202)+1 种基金中央高校基本科研业务费(批准号:CXJJ-2019-412)专项资金资助部分受到上海市数据科技与决策前沿科学研究基地(Shanghai Research Center for Data Science and Decision Technology)资助。
文摘Due to the majority of time people spent indoors,indoor air quality is not only critical to people’s health,comfort,but can also significantly influence occupants perception on indoor environment.Air quality is closely related to many factors including thermal parameters,pollutant concentrations,and ventilation performance.However,the current building indoor air quality evaluation method is based the objective measurement of indoor parameters,without considering occupants’subjective perception.This paper is aimed at summarizing a profound review on the PAQ evaluation method.Comparisons among various PAQ evaluating methods with advantages,similarities and differences were conducted.Analysis of literatures about indoor air quality in Chinese residential buildings field is also summarized,and discussion on the subjective influence of temperature and relative humidity,venti-lation performance,volatile organic compounds(VOCs)concentration,and particulate matters on perceived air quality is carried out.
基金supported by the National Key R&D Program of China(No.2017YFC0210005)the National Natural Science Foundation of China(Nos.41875166,41875163 and 41375129)
文摘Vapor wall losses can affect the yields of secondary organic aerosol.The effects of surfaceto-volume(S/V)ratio and relative humidity(RH)on the vapor-wall interactions were investigated in this study.The oxygenated volatile organic compounds(OVOCs)were generated from toluene-H_(2)O_(2)irradiations.The average gas to wall loss rate constant(k_(gw))of OVOCs in a 400 L reactor(S/V=7.5 m^(-1))is 2.47(2.41 under humid conditions)times higher than that in a 5000 L reactor(S/V=3.6 m-1)under dry conditions.In contrast,the average desorption rate constant(k_(wg))of OVOCs in 400 L reactor is only 1.37(1.20 under humid conditions)times higher than that in 5000 L reactor under dry conditions.It shows that increasing the S/V ratio can promote the wall losses of OVOCs.By contrast,the RH effect on k_(gw)is not prominent.The average k_(gw)value under humid conditions is almost the same as under dry conditions in the 400 L(5000 L)reactor.However,increasing RH can decrease the desorption rates.The average k_(wg)value under dry conditions is 1.45(1.27)times higher than that under humid conditions in the 400 L(5000 L)reactor.The high RH can increase the partitioning equilibrium timescales and enhance the wall losses of OVOCs.
