The energy equilibrium equation and discrete ordinate methods are combined to establish the one-dimensional steady heat transfer mathematical model of multi-layer thermal insulations (MTIs) in metallic thermal prote...The energy equilibrium equation and discrete ordinate methods are combined to establish the one-dimensional steady heat transfer mathematical model of multi-layer thermal insulations (MTIs) in metallic thermal protection systems. The inverse problem of heat transfer is solved by the genetic algorithm and data from the steady heat transfer experiment of fibrous thermal insulations. The density radiation attenuation coefficient, the albedo of fibrous thermal insulations and the surface emissivity of reflective screens are optimized. Finally, the one-dimensional steady heat transfer model of MTIs with optimized thermal physical parameters is verified by experimental data of the effective MTI conductivity.展开更多
Effective temperature level of stream, namely stream pseudo temperature, is determined by its actual temperature and heat transfer temperature difference contribution value. Heat transfer temperature difference con-tr...Effective temperature level of stream, namely stream pseudo temperature, is determined by its actual temperature and heat transfer temperature difference contribution value. Heat transfer temperature difference con-tribution value of a stream depends on its heat transfer film coefficient, cost per unit heat transfer area, actual tem-perature, and so on. In the determination of the suitable heat transfer temperature difference contribution values of the stream, the total annual cost of multistream heat exchanger network (MSHEN) is regarded as an objective func-tion, and genetic/simulated annealing algorithm (GA/SA) is adopted for optimizing the heat transfer temperature difference contribution values of the stream. The stream pseudo temperatures are subsequently obtained. On the ba-sis of stream pseudo temperature, optimized MSHEN can be attained by the temperature-enthalpy (T-H) diagram method. This approach is characterized with fewer decision variables and higher feasibility of solutions. The calcu-lation efficiency of GA/SA can be remarkably enhanced by this approach and more probability is shown in search-ing the global optimum solution. Hence this approach is presented for solving industrial-sized MSHEN which is difficult to deal by traditional algorithm. Moreover, in the optimization of stream heat transfer temperature differ-ence contribution values, the effects of the stream temperature, the heat transfer film coefficient, and the construc-tion material of heat exchangers are considered, therefore this approach can be used to optimize and design heat exchanger network (HEN) with unequal heat transfer film coefficients and different of construction materials. The performance of the proposed approach has been demonstrated with three examples and the obtained solutions are compared with those available in literatures. The results show that the large-scale MSHEN synthesis problems can be solved to obtain good solutions with the modest computational effort.展开更多
In this paper, a new approach using artificial neural network and genetic algorithm for the optimization of the thermally coupled distillation is presented. Mathematical model can be constructed with artificial neura...In this paper, a new approach using artificial neural network and genetic algorithm for the optimization of the thermally coupled distillation is presented. Mathematical model can be constructed with artificial neural network based on the simulation results with ASPEN PLUS. Modified genetic algorithm was used to optimize the model. With the proposed model and optimization arithmetic, mathematical model can be calculated, decision variables and target value can be reached automatically and quickly. A practical example is used to demonstrate the algorithm.展开更多
The temperature of proton exchange membrane fuel cell stack and the stoichiometric oxygen in cathode have relationship with the performance and life span of fuel cells closely. The thermal coefficients were taken as i...The temperature of proton exchange membrane fuel cell stack and the stoichiometric oxygen in cathode have relationship with the performance and life span of fuel cells closely. The thermal coefficients were taken as important factors affecting the temperature distribution of fuel cells and components. According to the experimental analysis, when the stoichiometric oxygen in cathode is greater than or equal to 1.8, the stack voltage loss is the least. A novel genetic algorithm was developed to identify and optimize the variables in dynamic thermal model of proton exchange membrane fuel cell stack, making the outputs of temperature model approximate to the actual temperature, and ensuring that the maximal error is less than 1 ℃. At the same time, the optimum region of stoichiometric oxygen is obtained, which is in the range of 1.8-2.2 and accords with the experimental analysis results. The simulation and experimental results show the effectiveness of the proposed algorithm.展开更多
The study aimed to determine the genetic variances of phytic acid (myo-inositol 1,2,3,4,5,6 hexakis-dihydrogen phosphate) (PA) and inorganic phosphorus contents (InP) in grains of tropical maize (Zea mays L.)....The study aimed to determine the genetic variances of phytic acid (myo-inositol 1,2,3,4,5,6 hexakis-dihydrogen phosphate) (PA) and inorganic phosphorus contents (InP) in grains of tropical maize (Zea mays L.). The understanding of genetic variances in PA and InP in tropical maize would be useful for breeding management in tropical region. A total of 16 Ki inbred lines and 26 new inbred lines of tropical maize were planted in Completely Randomized Design (CRD) on the dry season 2008 at lnseechandrastitya Institute for Crops Research and Development, Thailand. The results showed that genotypic differences were highly significant (P 〈 0.01) for InP in both sources of germplasm, but genotype effect only was found significant in new inbred lines for PA content. The values for broad sense heritability (h2b) was generally lower on PA in maize grains compared with InP both in Ki and new inbred lines [h^2b of PA: 2.42 (Ki), 14.18 (commercial hybrid extracted); h^2b of InP: 32 (Ki) and 29.53 (commercial hybrid extracted)].展开更多
Triploidy was induced in Chinese shrimp Fenneropenaeus chinensis by 30±0.5℃heat shock treatment (initiated at 20 min after fertilization) for 10 min to inhibit the release of PB2 at 18.0℃. The highest triploid ...Triploidy was induced in Chinese shrimp Fenneropenaeus chinensis by 30±0.5℃heat shock treatment (initiated at 20 min after fertilization) for 10 min to inhibit the release of PB2 at 18.0℃. The highest triploid rate obtained was 84.5% in nauplius stage. The effect of heat shock treatment on meiosis and cleavage of eggs was investigated in this work aimed to establish efficient procedures for triploid induction and to gain understanding of the mechanism of triploid production. Three pronuclei that could be observed in the treated eggs under fluorescence microscope developed into triploid embryos. Some abnormal chromosome behavior was observed in heat shocked eggs.展开更多
AIM: To investigate the relationship between encapsulating peritonitis and familial Mediterranean fever (FMF). METHODS: The patient had a history of type 2 diabetes and Iaparoscopic cholecystectomy was performed one y...AIM: To investigate the relationship between encapsulating peritonitis and familial Mediterranean fever (FMF). METHODS: The patient had a history of type 2 diabetes and Iaparoscopic cholecystectomy was performed one year ago for cholelithiasis. Eleven months after the operation she developed massive ascites. Biochemical evaluation revealed hyperglycemia, mild Fe deficiency anemia, hypoalbuminemia and a CA-125 level of 2 700 IU. Ascitic evaluation showed characteristics of exudation with a cell count of 580/mm^3. Abdominal CT showed omental thickening and massive ascites. At exploratory laparotomy there was generalized thickening of the peritoneum and a Iaparoscopic clip encapsulated by fibrous tissue was found adherent to the uterus. Biopsies were negative for malignancy and a prophilactic total abdominal hysterectomy and bilateral salpingooophorectomy were performed. RESULTS: The histopathological evaluation was compatible with chronic nonspecific findings and mild mesothelial proliferation and chronic inflammation at the uterine serosa and liver biopsy showed inactive cirrhosis. CONCLUSION: The patient was evaluated as sclerosing encapsulating peritonitis induced by the iaparoscopic clip acting as a foreign body. Due to the fact that the patient had FMF the immune response was probably exaggerated.展开更多
The latest effective utilization of bamboo resources is changing from domestic industry to mechanical industry. This fact will be required a lot of raw material from a large scale factory, therefore, what kind of bamb...The latest effective utilization of bamboo resources is changing from domestic industry to mechanical industry. This fact will be required a lot of raw material from a large scale factory, therefore, what kind of bamboo should be selected for a material. So, this study discussed on this matter through investigation and experiment. Results of this study are as follows: 1) Characteristics of bamboo different from trees and grass; 2) Environmental factors: a) annual mean temperature in 10-15 ℃ shows good growth of culm in temperate area and more than 20 ℃ also shows in tropical area, b) Rainfall: more than 1,000 mm year-1 is necessary for growth of culm in temperate and tropical area, and still more in addition to two times of 100 mm month-1 in temperate area, and three times of 200 mm month-l in tropical area, c) Soil and topography: brown colored soil and flat or gentle slope show better growth in temperate area, but red colored soil and slope are not suitable in tropical area, d) Geographical distribution of bamboo related with growth type shown in Figs. 1-3. Productivity of bamboo: annual productivity of bamboo is the biggest compared with other type of vegetation; 4) Selection of two growth type of bamboo: many big bamboos are growing in tropical area; 5) Furthermore items discussed in this report.展开更多
Chickpea (Cicer arietinum L.) is an important cool season food legumes with indeterminate growth habit. The crop is valued for its nutritive seeds and used as animal feed in many developing countries. ...Chickpea (Cicer arietinum L.) is an important cool season food legumes with indeterminate growth habit. The crop is valued for its nutritive seeds and used as animal feed in many developing countries. The productivity of the crop is constrained by several abiotic stresses, among which drought stress is one of the key determinants of crop performance aaccounting for 40-50% yield reduction globally. The present study was conducted to screen, evaluate and select chickpea genotypes possessing high yield potential under drought stress condition at ASALs (arid and semi-arid lands) of Kenya. The experiment was conducted at Chemeron dry land and Eco-tourism Research station, Egerton University and Kenya Agricultural and Livestock Research Institute (KALRO), Pekerra, Marigat, Baringo County. The genotypes were planted in RCBD (randomized complete block design) in three replicates at a spacing of 30 cm × 10 cm, giving a plant density of approximately 25 plants/m2. Combined analysis of variance revealed existence of highly significant differences among the tested genotypes for most of the agronomic traits. Overall, the highest grain yield was obtained from ICCV 92944 (1,173 kg/ha), ICCV 92318 (1,103 kg/ha) and CAVIR (975 kg/ha), ICCV 92318 (967 kg/ha), ICCV 00108 (956 kg/ha) and ICC 4958 (921 kg/ha): possibly due to its comparatively higher drought (and heat) tolerance, and hence could be used as sources of drought tolerance in further breeding programs. This study was carried out in few drought tolerant sites and further more sites need to be evaluated in addition to other drought and heat screening and optimization of protocols, facilities and analytical approaches to identify better genotypes that respond appropriately to climate change.展开更多
This paper presents an assessment of the spatial quality of a pedestrian street located in downtown Bauru, S^o Paulo State, Brazil, from the application of some urban sustainability indicators. Multi-method was used t...This paper presents an assessment of the spatial quality of a pedestrian street located in downtown Bauru, S^o Paulo State, Brazil, from the application of some urban sustainability indicators. Multi-method was used to evaluate the thermal comfort quality of users, urban accessibility and preservation of architectural heritage. The results show that the sustainability indicators, apart from being effective tools in identifying problems, can assist local managers in decision making, planning and monitoring of pedestrian public space. These indicators contribute to a broad diagnosis of the pedestrian street and also the formulation of programs, projects and municipal policies, aimed at providing a better life quality for pedestrians.展开更多
In this article, The genetic algorithm method was proposed, that is, to establish the box structure's nonlinear three-dimension optimization numerical model based on thermo-mechanical coupling algorithm, and the obje...In this article, The genetic algorithm method was proposed, that is, to establish the box structure's nonlinear three-dimension optimization numerical model based on thermo-mechanical coupling algorithm, and the objective function of welding distortion has been utilized to determine an optimum welding sequence by optimization simulation. The validity of genetic algorithm method combining with the thermo-mechanical nonlinear finite element model is verified by comparison with the experimental data where available. By choosing the appropriate objective function for the considered case, an optimum weldiing.sequence is determined by a genetic algorithm. All done in this study indicates that the new method presented in this article will have important practical application for designing the welding technical parameters in the future.展开更多
Geothermal is a fast-growing alternative heat source for HVAC systems, however, the initial cost of using a ground source HVAC system is higher compared to an air source system. Studies about system design and operati...Geothermal is a fast-growing alternative heat source for HVAC systems, however, the initial cost of using a ground source HVAC system is higher compared to an air source system. Studies about system design and operation are necessary to reduce the initial cost and ensure that the ground source heat pump system has high efficiency, resulting in a lower total life-time cost. In this study, a multi-variable evolutionary computation algorithm is proposed for generating optimal parameters for a geothermal source HVAC system. The system was modeled and simulated using MATLAB. The design parameters were calculated by minimizing the energy consumption, Based on an experimental building, a case study was presented. Using this model, the optimal set points were calculated and used as a designed system. Energy consumption of this system was reduced by about 10% compared to the system operated with a fixed supply cold water temperature (7 ℃).展开更多
Using high pressure and geological condition simulation vessels, we conducted hydrous pyrolysis experiments of kerogen, solid bitumen and liquid hydrocarbons in southern China in order to study the processes of gas ge...Using high pressure and geological condition simulation vessels, we conducted hydrous pyrolysis experiments of kerogen, solid bitumen and liquid hydrocarbons in southern China in order to study the processes of gas generation and derive geo- chemical indicators of gas genesis under approximate pressure and temperature. The results indicate that gas generation productivity of different marine material decreased in the ganic matter (solid bitumen and heavy oil), and kerogen. order of crude oil (light oil and condensate), dispersed soluble or- Under identical temperature-pressure regimes, pyrolysates derived from kerogen and dispersed soluble organic matter display drastically different geochemical characteristics. For example, the δ13Cc02-δ13C1 values of gaseous products from dispersed soluble organic matter are greater than 20%o, whereas those from kerogen are less than 20%~. The 813C1 values of pyrolysates from different marine hydrocarbon sources generally increase with pyrolysis temperature, but are always lower than those of the source precursors. The δ13C values of ethane and propane in the pyrolysates also increase with increasing pyrolysis temperature, eventually approaching that of their sources, at peak hydro- carbon generation. At high-over mature stages, the δ13C values of ethane and propane are often greater than those of their sources but close to those of coal gases, and thus become ineffective as gas genetic indicators. Ln(CffC3) can clearly distin- guish kerogen degradation gas from oil cracking gas and Ln(CJC2)-(δ13C1-δ13C2) can be an effective indicator for distinguishing oil cracking gas from dispersed soluble organic matter cracking gas.展开更多
文摘The energy equilibrium equation and discrete ordinate methods are combined to establish the one-dimensional steady heat transfer mathematical model of multi-layer thermal insulations (MTIs) in metallic thermal protection systems. The inverse problem of heat transfer is solved by the genetic algorithm and data from the steady heat transfer experiment of fibrous thermal insulations. The density radiation attenuation coefficient, the albedo of fibrous thermal insulations and the surface emissivity of reflective screens are optimized. Finally, the one-dimensional steady heat transfer model of MTIs with optimized thermal physical parameters is verified by experimental data of the effective MTI conductivity.
基金Supported by the Deutsche Forschungsgemeinschaft (DFG No.RO 294/9).
文摘Effective temperature level of stream, namely stream pseudo temperature, is determined by its actual temperature and heat transfer temperature difference contribution value. Heat transfer temperature difference con-tribution value of a stream depends on its heat transfer film coefficient, cost per unit heat transfer area, actual tem-perature, and so on. In the determination of the suitable heat transfer temperature difference contribution values of the stream, the total annual cost of multistream heat exchanger network (MSHEN) is regarded as an objective func-tion, and genetic/simulated annealing algorithm (GA/SA) is adopted for optimizing the heat transfer temperature difference contribution values of the stream. The stream pseudo temperatures are subsequently obtained. On the ba-sis of stream pseudo temperature, optimized MSHEN can be attained by the temperature-enthalpy (T-H) diagram method. This approach is characterized with fewer decision variables and higher feasibility of solutions. The calcu-lation efficiency of GA/SA can be remarkably enhanced by this approach and more probability is shown in search-ing the global optimum solution. Hence this approach is presented for solving industrial-sized MSHEN which is difficult to deal by traditional algorithm. Moreover, in the optimization of stream heat transfer temperature differ-ence contribution values, the effects of the stream temperature, the heat transfer film coefficient, and the construc-tion material of heat exchangers are considered, therefore this approach can be used to optimize and design heat exchanger network (HEN) with unequal heat transfer film coefficients and different of construction materials. The performance of the proposed approach has been demonstrated with three examples and the obtained solutions are compared with those available in literatures. The results show that the large-scale MSHEN synthesis problems can be solved to obtain good solutions with the modest computational effort.
文摘In this paper, a new approach using artificial neural network and genetic algorithm for the optimization of the thermally coupled distillation is presented. Mathematical model can be constructed with artificial neural network based on the simulation results with ASPEN PLUS. Modified genetic algorithm was used to optimize the model. With the proposed model and optimization arithmetic, mathematical model can be calculated, decision variables and target value can be reached automatically and quickly. A practical example is used to demonstrate the algorithm.
基金Project (2003AA517020) supported by the National High-Technology Research Plan of China
文摘The temperature of proton exchange membrane fuel cell stack and the stoichiometric oxygen in cathode have relationship with the performance and life span of fuel cells closely. The thermal coefficients were taken as important factors affecting the temperature distribution of fuel cells and components. According to the experimental analysis, when the stoichiometric oxygen in cathode is greater than or equal to 1.8, the stack voltage loss is the least. A novel genetic algorithm was developed to identify and optimize the variables in dynamic thermal model of proton exchange membrane fuel cell stack, making the outputs of temperature model approximate to the actual temperature, and ensuring that the maximal error is less than 1 ℃. At the same time, the optimum region of stoichiometric oxygen is obtained, which is in the range of 1.8-2.2 and accords with the experimental analysis results. The simulation and experimental results show the effectiveness of the proposed algorithm.
文摘The study aimed to determine the genetic variances of phytic acid (myo-inositol 1,2,3,4,5,6 hexakis-dihydrogen phosphate) (PA) and inorganic phosphorus contents (InP) in grains of tropical maize (Zea mays L.). The understanding of genetic variances in PA and InP in tropical maize would be useful for breeding management in tropical region. A total of 16 Ki inbred lines and 26 new inbred lines of tropical maize were planted in Completely Randomized Design (CRD) on the dry season 2008 at lnseechandrastitya Institute for Crops Research and Development, Thailand. The results showed that genotypic differences were highly significant (P 〈 0.01) for InP in both sources of germplasm, but genotype effect only was found significant in new inbred lines for PA content. The values for broad sense heritability (h2b) was generally lower on PA in maize grains compared with InP both in Ki and new inbred lines [h^2b of PA: 2.42 (Ki), 14.18 (commercial hybrid extracted); h^2b of InP: 32 (Ki) and 29.53 (commercial hybrid extracted)].
文摘Triploidy was induced in Chinese shrimp Fenneropenaeus chinensis by 30±0.5℃heat shock treatment (initiated at 20 min after fertilization) for 10 min to inhibit the release of PB2 at 18.0℃. The highest triploid rate obtained was 84.5% in nauplius stage. The effect of heat shock treatment on meiosis and cleavage of eggs was investigated in this work aimed to establish efficient procedures for triploid induction and to gain understanding of the mechanism of triploid production. Three pronuclei that could be observed in the treated eggs under fluorescence microscope developed into triploid embryos. Some abnormal chromosome behavior was observed in heat shocked eggs.
文摘AIM: To investigate the relationship between encapsulating peritonitis and familial Mediterranean fever (FMF). METHODS: The patient had a history of type 2 diabetes and Iaparoscopic cholecystectomy was performed one year ago for cholelithiasis. Eleven months after the operation she developed massive ascites. Biochemical evaluation revealed hyperglycemia, mild Fe deficiency anemia, hypoalbuminemia and a CA-125 level of 2 700 IU. Ascitic evaluation showed characteristics of exudation with a cell count of 580/mm^3. Abdominal CT showed omental thickening and massive ascites. At exploratory laparotomy there was generalized thickening of the peritoneum and a Iaparoscopic clip encapsulated by fibrous tissue was found adherent to the uterus. Biopsies were negative for malignancy and a prophilactic total abdominal hysterectomy and bilateral salpingooophorectomy were performed. RESULTS: The histopathological evaluation was compatible with chronic nonspecific findings and mild mesothelial proliferation and chronic inflammation at the uterine serosa and liver biopsy showed inactive cirrhosis. CONCLUSION: The patient was evaluated as sclerosing encapsulating peritonitis induced by the iaparoscopic clip acting as a foreign body. Due to the fact that the patient had FMF the immune response was probably exaggerated.
文摘The latest effective utilization of bamboo resources is changing from domestic industry to mechanical industry. This fact will be required a lot of raw material from a large scale factory, therefore, what kind of bamboo should be selected for a material. So, this study discussed on this matter through investigation and experiment. Results of this study are as follows: 1) Characteristics of bamboo different from trees and grass; 2) Environmental factors: a) annual mean temperature in 10-15 ℃ shows good growth of culm in temperate area and more than 20 ℃ also shows in tropical area, b) Rainfall: more than 1,000 mm year-1 is necessary for growth of culm in temperate and tropical area, and still more in addition to two times of 100 mm month-1 in temperate area, and three times of 200 mm month-l in tropical area, c) Soil and topography: brown colored soil and flat or gentle slope show better growth in temperate area, but red colored soil and slope are not suitable in tropical area, d) Geographical distribution of bamboo related with growth type shown in Figs. 1-3. Productivity of bamboo: annual productivity of bamboo is the biggest compared with other type of vegetation; 4) Selection of two growth type of bamboo: many big bamboos are growing in tropical area; 5) Furthermore items discussed in this report.
文摘Chickpea (Cicer arietinum L.) is an important cool season food legumes with indeterminate growth habit. The crop is valued for its nutritive seeds and used as animal feed in many developing countries. The productivity of the crop is constrained by several abiotic stresses, among which drought stress is one of the key determinants of crop performance aaccounting for 40-50% yield reduction globally. The present study was conducted to screen, evaluate and select chickpea genotypes possessing high yield potential under drought stress condition at ASALs (arid and semi-arid lands) of Kenya. The experiment was conducted at Chemeron dry land and Eco-tourism Research station, Egerton University and Kenya Agricultural and Livestock Research Institute (KALRO), Pekerra, Marigat, Baringo County. The genotypes were planted in RCBD (randomized complete block design) in three replicates at a spacing of 30 cm × 10 cm, giving a plant density of approximately 25 plants/m2. Combined analysis of variance revealed existence of highly significant differences among the tested genotypes for most of the agronomic traits. Overall, the highest grain yield was obtained from ICCV 92944 (1,173 kg/ha), ICCV 92318 (1,103 kg/ha) and CAVIR (975 kg/ha), ICCV 92318 (967 kg/ha), ICCV 00108 (956 kg/ha) and ICC 4958 (921 kg/ha): possibly due to its comparatively higher drought (and heat) tolerance, and hence could be used as sources of drought tolerance in further breeding programs. This study was carried out in few drought tolerant sites and further more sites need to be evaluated in addition to other drought and heat screening and optimization of protocols, facilities and analytical approaches to identify better genotypes that respond appropriately to climate change.
文摘This paper presents an assessment of the spatial quality of a pedestrian street located in downtown Bauru, S^o Paulo State, Brazil, from the application of some urban sustainability indicators. Multi-method was used to evaluate the thermal comfort quality of users, urban accessibility and preservation of architectural heritage. The results show that the sustainability indicators, apart from being effective tools in identifying problems, can assist local managers in decision making, planning and monitoring of pedestrian public space. These indicators contribute to a broad diagnosis of the pedestrian street and also the formulation of programs, projects and municipal policies, aimed at providing a better life quality for pedestrians.
文摘In this article, The genetic algorithm method was proposed, that is, to establish the box structure's nonlinear three-dimension optimization numerical model based on thermo-mechanical coupling algorithm, and the objective function of welding distortion has been utilized to determine an optimum welding sequence by optimization simulation. The validity of genetic algorithm method combining with the thermo-mechanical nonlinear finite element model is verified by comparison with the experimental data where available. By choosing the appropriate objective function for the considered case, an optimum weldiing.sequence is determined by a genetic algorithm. All done in this study indicates that the new method presented in this article will have important practical application for designing the welding technical parameters in the future.
文摘Geothermal is a fast-growing alternative heat source for HVAC systems, however, the initial cost of using a ground source HVAC system is higher compared to an air source system. Studies about system design and operation are necessary to reduce the initial cost and ensure that the ground source heat pump system has high efficiency, resulting in a lower total life-time cost. In this study, a multi-variable evolutionary computation algorithm is proposed for generating optimal parameters for a geothermal source HVAC system. The system was modeled and simulated using MATLAB. The design parameters were calculated by minimizing the energy consumption, Based on an experimental building, a case study was presented. Using this model, the optimal set points were calculated and used as a designed system. Energy consumption of this system was reduced by about 10% compared to the system operated with a fixed supply cold water temperature (7 ℃).
基金supported by Petroleum & Chemical United Fund Project(Grant No. 40739902)
文摘Using high pressure and geological condition simulation vessels, we conducted hydrous pyrolysis experiments of kerogen, solid bitumen and liquid hydrocarbons in southern China in order to study the processes of gas generation and derive geo- chemical indicators of gas genesis under approximate pressure and temperature. The results indicate that gas generation productivity of different marine material decreased in the ganic matter (solid bitumen and heavy oil), and kerogen. order of crude oil (light oil and condensate), dispersed soluble or- Under identical temperature-pressure regimes, pyrolysates derived from kerogen and dispersed soluble organic matter display drastically different geochemical characteristics. For example, the δ13Cc02-δ13C1 values of gaseous products from dispersed soluble organic matter are greater than 20%o, whereas those from kerogen are less than 20%~. The 813C1 values of pyrolysates from different marine hydrocarbon sources generally increase with pyrolysis temperature, but are always lower than those of the source precursors. The δ13C values of ethane and propane in the pyrolysates also increase with increasing pyrolysis temperature, eventually approaching that of their sources, at peak hydro- carbon generation. At high-over mature stages, the δ13C values of ethane and propane are often greater than those of their sources but close to those of coal gases, and thus become ineffective as gas genetic indicators. Ln(CffC3) can clearly distin- guish kerogen degradation gas from oil cracking gas and Ln(CJC2)-(δ13C1-δ13C2) can be an effective indicator for distinguishing oil cracking gas from dispersed soluble organic matter cracking gas.