Air pollution control has always been a global challenge, and significant progress has been made in recent years in controlling air pollutants. However, in some major cities, air pollutant concentrations still exceed ...Air pollution control has always been a global challenge, and significant progress has been made in recent years in controlling air pollutants. However, in some major cities, air pollutant concentrations still exceed the standards. Some scholars have used linear models or conditional autoregressive iterative models to apply the VaR method to predict pollutant concentrations. However, traditional methods based on quantile regression estimation can lead to inadequate risk estimates. Therefore, we propose a method based on the Conditional Autoregressive Value at Risk (CAViaR) model, which uses the kth power expectile regression to estimate VaR. This method does not specify the type of the distribution of data, is easier to calculate the asymptotic variance, more sensitive to extreme values. Applying our method to the data of PM10 in Beijing, we investigate the fitting effects in the case of k = 1, k = 2, and k = 1.9 through predictive tests. The results show that the kth power expectile regression estimates are better than quantile and expectile regression estimates to some extent.展开更多
Using the grey correlation analysis,it can be concluded that the reactor pressure vessel wall temperature has the strongest effect on the passive residual heat removal system in HTR (High Temperature gas-cooled Reacto...Using the grey correlation analysis,it can be concluded that the reactor pressure vessel wall temperature has the strongest effect on the passive residual heat removal system in HTR (High Temperature gas-cooled Reactor), the chimney height takes the second place,and the influence of inlet air temperature of the chimney is the least.This conclusion is the same as that analyzed by the traditional method.According to the grey model theory,the GM(1,1) and GM(1,3) model are built based on the inlet air temperature of chimney,pressure vessel temperature and the chimney height.Then the effect of three factors on the heat removal power is studied in this paper.The model plays an important role on data prediction,and is a new method for studying the heat removal power.The method can provide a new theoretical analysis to the passive residual heat removal system of HTR.展开更多
In order to identify the day and night pollution sources of PM10 in ambient air in Longyan City,the authors analyzed the elemental composition of respirable particulate matters in the day and night ambient air samples...In order to identify the day and night pollution sources of PM10 in ambient air in Longyan City,the authors analyzed the elemental composition of respirable particulate matters in the day and night ambient air samples and various pollution sources which were collected in January 2010 in Longyan with inductivity coupled plasma-mass spectrometry（ICP-MS）.Then chemical mass balance（CMB） model and factor analysis（FA） method were applied to comparatively study the inorganic components in the sources and receptor samples.The results of factor analysis show that the major sources were road dust,waste incineration and mixed sources which contained automobile exhaust,soil dust/secondary dust and coal dust during the daytime in Longyan City,China.There are two major sources of pollution which are soil dust and mixture sources of automobile exhaust and secondary dust during the night in Longyan.The results of CMB show that the major sources are secondary dust,automobile exhaust and road dust during the daytime in Longyan.The major sources are secondary dust,soil dust and automobile exhaust during the night in Longyan.The results of the two methods are similar to each other and the results will guide us to plan to control the PM10 pollution sources in Longyan.展开更多
In the lower parts of oil reservoirs Chang 9 and Chang 10 of the Yanchang Formation are oil-bearing layers newly found in oil exploration in the Ordos Basin.Based on GC,GC-MS analyses of saturated hydrocarbons from cr...In the lower parts of oil reservoirs Chang 9 and Chang 10 of the Yanchang Formation are oil-bearing layers newly found in oil exploration in the Ordos Basin.Based on GC,GC-MS analyses of saturated hydrocarbons from crude oils and source rocks,reservoir fluid inclusions and BasinMod,the origin of crude oils,accumulation period and accumulation models are discussed in combination with other petroleum geology data in this paper.The result shows that(1) there are two different types of crude oils in oil reservoir Chang 9 in the Longdong and Jiyuan regions:crude oils of typeⅠ(Well D86,Well A44,Well A75,Well B227,Well X62 and Well Z150) are mainly de-rived from the Chang 7 source rocks(including mudstones and shales) and distributed in the Jiyuan and Longdong regions;those of typeⅡ(Well Z14 and Well Y427),are distributed in the Longdong region,which are derived from the Chang 9 source rocks.Crude oils from oil reservoir Chang 10 in the Shanbei region are mainly derived from the Chang-9 source rocks;(2) there are two phases of hydrocarbon filling in oil reservoir Chang 9 in the Jiyuan and Longdong regions and oil reservoir Chang 10 in the Shanbei region:The first phase started at the early stage of J2z.The process of hydrocarbon filling was discontinuous in the Late Jurassic,because of the tectonic-thermal event in the Ordos Basin.The second phase was the main accumulation period,and hydrocarbons began to accumulate from the late stage of J2a to the middle-late of K1,mainly at the middle-late stage of K1;(3) there exist two types of accu-mulation models in oil reservoirs Chang 9 and Chang 10 of the Yanchang Formation:source rocks of the reservoirs in oil reservoir Chang 9 in the Jiyuan region and oil reservoir Chang 10 in the Shanbei region,the mixed type of reservoirs on the lateral side of source rocks and source rocks of the reservoirs in oil reservoir Chang 9 in the Long-dong region.展开更多
Interleukin-10 (IL-10) is an important cytokine that plays a pivotal role in natural and adaptive immune systems. However, in lower vertebrates, especially in teleost the receptor of this cytokine is still largely unk...Interleukin-10 (IL-10) is an important cytokine that plays a pivotal role in natural and adaptive immune systems. However, in lower vertebrates, especially in teleost the receptor of this cytokine is still largely unknown. This paper described the cloning and characterization of grass carp interleukin-10 receptor 1 (gcIL10R1) and the 3D structure of its extracellular domain was predicted. The gcIL10R1 cDNA included 180 bp5’ untranslated region (UTR), 870 bp3’ UTR and an open reading frame (ORF) of 1632 bp. The ORF was found to encode a 543 amino acid protein with a putative JAK1 binding site, one STAT3 binding site. The phylogenetic analysis clusters gcIL10R1 with other teleost IL10R1s but independently of the amphibian, avian and mammalian IL10R1s. The 3D structure of its extracellular domain was the first homology model of a fish IL10R1 that revealed a high similarity with its mammalian and avian counterparts.展开更多
The technique of modeling operating temperature variations of shell-and-tube heat exchanger 10-E-01 of kerosene-crude oil streams of Port Harcourt refinery crude distillation unit is presented in this research. A...The technique of modeling operating temperature variations of shell-and-tube heat exchanger 10-E-01 of kerosene-crude oil streams of Port Harcourt refinery crude distillation unit is presented in this research. Appropriate first-order model equations were developed applying principles of energy balance. The differential equations developed for the process streams which exchanged heat was evaluated numerically to predict the temperature variations as a function of time. The relevant parameters associated with typical heat exchanger works were calculated using plant data of 10-E-02. The model strives to predict the final kerosene temperature from 488 to 353.6 K. While the crude oil streams temperature rose from 313 to 353.6 K. The developed model enables the operator to predict the final temperature at the kerosene hydro-treating unit and thereby prevent regular emergency shutdowns due to excessive temperature rise.展开更多
The present paper discusses the application of localized linear models for the prediction of hourly PM10 concentration values. The advantages of the proposed approach lies in the clustering of the data based on a comm...The present paper discusses the application of localized linear models for the prediction of hourly PM10 concentration values. The advantages of the proposed approach lies in the clustering of the data based on a common property and the utilization of the target variable during this process, which enables the development of more coherent models. Two alternative localized linear modelling approaches are developed and compared against benchmark models, one in which data are clustered based on their spatial proximity on the embedding space and one novel approach in which grouped data are described by the same linear model. Since the target variable is unknown during the prediction stage, a complimentary pattern recognition approach is developed to account for this lack of information. The application of the developed approach on several PM10 data sets from the Greater Athens Area, Helsinki and London monitoring networks returned a significant reduction of the prediction error under all examined metrics against conventional forecasting schemes such as the linear regression and the neural networks.展开更多
Two multidentate ligands 2,9-di[6＇-（2″-hydroxyl-3″-methoxyphenyl）-n-2＇,5＇-diazahexyl]-1,10-phenanthroline（LA）and 2,9-di（6＇-α-phenol-n-2＇,5＇-diazahexyl）-1,10-phenanthroline（LB）were synthesized and full...Two multidentate ligands 2,9-di[6＇-（2″-hydroxyl-3″-methoxyphenyl）-n-2＇,5＇-diazahexyl]-1,10-phenanthroline（LA）and 2,9-di（6＇-α-phenol-n-2＇,5＇-diazahexyl）-1,10-phenanthroline（LB）were synthesized and fully characterized.Protonation of the ligands and the stability of the complexes of the ligands with divalent metal ions were investigated.The trinuclear metal complexes [Cu（Ⅱ）and Zn（Ⅱ）] of the ligands were studied,as catalysts,for the transphosphorylation of the RNA-model substrate 2-hydroxypropyl-p-nitrophenyl phosphate（HPNP）.The second-order rate constants of HPNP-hydrolysis catalyzed by M3L and M3LH-1 were obtained,which indicated that Zn3LBH-1 was the most efficient catalyst among them.The proposed mechanisms included the activation of the substrate via binding to the metal ions and intramolecular nucleophilic attack by the deprotonated C2-hydroxyl of HPNP.展开更多
文摘Air pollution control has always been a global challenge, and significant progress has been made in recent years in controlling air pollutants. However, in some major cities, air pollutant concentrations still exceed the standards. Some scholars have used linear models or conditional autoregressive iterative models to apply the VaR method to predict pollutant concentrations. However, traditional methods based on quantile regression estimation can lead to inadequate risk estimates. Therefore, we propose a method based on the Conditional Autoregressive Value at Risk (CAViaR) model, which uses the kth power expectile regression to estimate VaR. This method does not specify the type of the distribution of data, is easier to calculate the asymptotic variance, more sensitive to extreme values. Applying our method to the data of PM10 in Beijing, we investigate the fitting effects in the case of k = 1, k = 2, and k = 1.9 through predictive tests. The results show that the kth power expectile regression estimates are better than quantile and expectile regression estimates to some extent.
基金Supported by the Special Funds for Major State Basic Research Projects of China (No.2007CB209800)National Key Laboratory of Bubble PhysicsNatural Circulation Funds
文摘Using the grey correlation analysis,it can be concluded that the reactor pressure vessel wall temperature has the strongest effect on the passive residual heat removal system in HTR (High Temperature gas-cooled Reactor), the chimney height takes the second place,and the influence of inlet air temperature of the chimney is the least.This conclusion is the same as that analyzed by the traditional method.According to the grey model theory,the GM(1,1) and GM(1,3) model are built based on the inlet air temperature of chimney,pressure vessel temperature and the chimney height.Then the effect of three factors on the heat removal power is studied in this paper.The model plays an important role on data prediction,and is a new method for studying the heat removal power.The method can provide a new theoretical analysis to the passive residual heat removal system of HTR.
基金Supported by the Natural Basic Research Program of China(No.2005CB422207)the Fund of Eco-enviromental Impacts and Protection in Devoloping and Utilizing of Oil-shale Resources(No.OSR-01-06)
文摘In order to identify the day and night pollution sources of PM10 in ambient air in Longyan City,the authors analyzed the elemental composition of respirable particulate matters in the day and night ambient air samples and various pollution sources which were collected in January 2010 in Longyan with inductivity coupled plasma-mass spectrometry（ICP-MS）.Then chemical mass balance（CMB） model and factor analysis（FA） method were applied to comparatively study the inorganic components in the sources and receptor samples.The results of factor analysis show that the major sources were road dust,waste incineration and mixed sources which contained automobile exhaust,soil dust/secondary dust and coal dust during the daytime in Longyan City,China.There are two major sources of pollution which are soil dust and mixture sources of automobile exhaust and secondary dust during the night in Longyan.The results of CMB show that the major sources are secondary dust,automobile exhaust and road dust during the daytime in Longyan.The major sources are secondary dust,soil dust and automobile exhaust during the night in Longyan.The results of the two methods are similar to each other and the results will guide us to plan to control the PM10 pollution sources in Longyan.
文摘In the lower parts of oil reservoirs Chang 9 and Chang 10 of the Yanchang Formation are oil-bearing layers newly found in oil exploration in the Ordos Basin.Based on GC,GC-MS analyses of saturated hydrocarbons from crude oils and source rocks,reservoir fluid inclusions and BasinMod,the origin of crude oils,accumulation period and accumulation models are discussed in combination with other petroleum geology data in this paper.The result shows that(1) there are two different types of crude oils in oil reservoir Chang 9 in the Longdong and Jiyuan regions:crude oils of typeⅠ(Well D86,Well A44,Well A75,Well B227,Well X62 and Well Z150) are mainly de-rived from the Chang 7 source rocks(including mudstones and shales) and distributed in the Jiyuan and Longdong regions;those of typeⅡ(Well Z14 and Well Y427),are distributed in the Longdong region,which are derived from the Chang 9 source rocks.Crude oils from oil reservoir Chang 10 in the Shanbei region are mainly derived from the Chang-9 source rocks;(2) there are two phases of hydrocarbon filling in oil reservoir Chang 9 in the Jiyuan and Longdong regions and oil reservoir Chang 10 in the Shanbei region:The first phase started at the early stage of J2z.The process of hydrocarbon filling was discontinuous in the Late Jurassic,because of the tectonic-thermal event in the Ordos Basin.The second phase was the main accumulation period,and hydrocarbons began to accumulate from the late stage of J2a to the middle-late of K1,mainly at the middle-late stage of K1;(3) there exist two types of accu-mulation models in oil reservoirs Chang 9 and Chang 10 of the Yanchang Formation:source rocks of the reservoirs in oil reservoir Chang 9 in the Jiyuan region and oil reservoir Chang 10 in the Shanbei region,the mixed type of reservoirs on the lateral side of source rocks and source rocks of the reservoirs in oil reservoir Chang 9 in the Long-dong region.
文摘Interleukin-10 (IL-10) is an important cytokine that plays a pivotal role in natural and adaptive immune systems. However, in lower vertebrates, especially in teleost the receptor of this cytokine is still largely unknown. This paper described the cloning and characterization of grass carp interleukin-10 receptor 1 (gcIL10R1) and the 3D structure of its extracellular domain was predicted. The gcIL10R1 cDNA included 180 bp5’ untranslated region (UTR), 870 bp3’ UTR and an open reading frame (ORF) of 1632 bp. The ORF was found to encode a 543 amino acid protein with a putative JAK1 binding site, one STAT3 binding site. The phylogenetic analysis clusters gcIL10R1 with other teleost IL10R1s but independently of the amphibian, avian and mammalian IL10R1s. The 3D structure of its extracellular domain was the first homology model of a fish IL10R1 that revealed a high similarity with its mammalian and avian counterparts.
文摘The technique of modeling operating temperature variations of shell-and-tube heat exchanger 10-E-01 of kerosene-crude oil streams of Port Harcourt refinery crude distillation unit is presented in this research. Appropriate first-order model equations were developed applying principles of energy balance. The differential equations developed for the process streams which exchanged heat was evaluated numerically to predict the temperature variations as a function of time. The relevant parameters associated with typical heat exchanger works were calculated using plant data of 10-E-02. The model strives to predict the final kerosene temperature from 488 to 353.6 K. While the crude oil streams temperature rose from 313 to 353.6 K. The developed model enables the operator to predict the final temperature at the kerosene hydro-treating unit and thereby prevent regular emergency shutdowns due to excessive temperature rise.
文摘The present paper discusses the application of localized linear models for the prediction of hourly PM10 concentration values. The advantages of the proposed approach lies in the clustering of the data based on a common property and the utilization of the target variable during this process, which enables the development of more coherent models. Two alternative localized linear modelling approaches are developed and compared against benchmark models, one in which data are clustered based on their spatial proximity on the embedding space and one novel approach in which grouped data are described by the same linear model. Since the target variable is unknown during the prediction stage, a complimentary pattern recognition approach is developed to account for this lack of information. The application of the developed approach on several PM10 data sets from the Greater Athens Area, Helsinki and London monitoring networks returned a significant reduction of the prediction error under all examined metrics against conventional forecasting schemes such as the linear regression and the neural networks.
基金Supported by the National Natural Science Foundation of China(Nos.20371028and20671052).
文摘Two multidentate ligands 2,9-di[6＇-（2″-hydroxyl-3″-methoxyphenyl）-n-2＇,5＇-diazahexyl]-1,10-phenanthroline（LA）and 2,9-di（6＇-α-phenol-n-2＇,5＇-diazahexyl）-1,10-phenanthroline（LB）were synthesized and fully characterized.Protonation of the ligands and the stability of the complexes of the ligands with divalent metal ions were investigated.The trinuclear metal complexes [Cu（Ⅱ）and Zn（Ⅱ）] of the ligands were studied,as catalysts,for the transphosphorylation of the RNA-model substrate 2-hydroxypropyl-p-nitrophenyl phosphate（HPNP）.The second-order rate constants of HPNP-hydrolysis catalyzed by M3L and M3LH-1 were obtained,which indicated that Zn3LBH-1 was the most efficient catalyst among them.The proposed mechanisms included the activation of the substrate via binding to the metal ions and intramolecular nucleophilic attack by the deprotonated C2-hydroxyl of HPNP.
