A primary jet vectoring using synthetic jet actuators with different exit configurations was investigated, and the main physical factors influencing jet vectoring were analyzed and summarized. The physical factors of ...A primary jet vectoring using synthetic jet actuators with different exit configurations was investigated, and the main physical factors influencing jet vectoring were analyzed and summarized. The physical factors of the pressure difference, the location and area of the lower pressure region, the component of the synthetic jet momentum and the entrainment ratio of the synthetic jet flow to primary jet flow directly control the vectoring force and the vectoring angle. Three characteristic parameters of the synthetic jet contribute to the pressure difference and the area of the lower pressure region Both the extension step and slope angle of the actuator exit have functions of regulating the location of the lower pressure region, the area of the lower pressure region, and the entrainment ratio of the synthetic jet flow to primary jet flow. The slope angle of the actuator exit has additional functions of regulating the component of the synthetic jet momentum. Based upon analyzing the physical factors of jet vectoring control with synthetic jets, the source variables of the physical factors were established. A preparatory control model of jet vectoring using synthetic jet actuator was presented, and it has the benefit of explaining the efficiency of jet vectoring using synthetic jet actuator with source variables at different values, and it indicates the optimal actuator is taking full advantage of the regulating function.展开更多
BACKGROUND: Iatrophysics can improve the velocity of local microcirculation at peripheral nerve injured sites and promote the recovery from injury. Research has shown that simultaneous application of two physical fac...BACKGROUND: Iatrophysics can improve the velocity of local microcirculation at peripheral nerve injured sites and promote the recovery from injury. Research has shown that simultaneous application of two physical factors has synergistic effects on the recovery of peripheral nerve function. OBJECTIVE: To treat patients that received peripheral nerve entrapment surgery with comprehensive rehabilitation by decimeter wave therapy and electrical stimulation, and to observe the clinical effects of promoting nerve function recovery. DESIGN: Randomized controlled study. SETTINGS: Department of Orthopaedics, the Third Hospital of Baoding; Department of Hand Surgery, the Third Hospital of Hebei Medical University; Woman-Children Healthcare Center, Southern District, Baoding. PARTICIPANTS: A total of 124 patients, who received peripheral nerve entrapment surgery, were selected from the Department of Orthopaedics, the Third Hospital of Baoding between July 2001 and May 2007. All patients met the diagnostic standard of peripheral nerve entrapment syndrome defined by Doctor Chen in 1995. All subjects gave informed consent for treatments and conditions involved. The experiment was approved by a local ethics committee. All patients were randomly divided into four groups: electrical stimulation group, decimeter wave group, compound physical factor group, and control group, with 31 subjects in each group. METHODS: Patients received neurolysis at an appropriate interval after hospitalization. (1) Multi-form wave therapeutic equipment made in China was used to treat patients in the electrical stimulation group after neurolysis. Wave form, stimulus width, interval time, and stimulus intensity were regulated based on the grade of nerve injury. The details were as follows: mild nerve injury: 50-100-ms stimulus width and 1 500-2 000-ms intervals; moderate nerve injury: 100-200-ms stimulus width and 3 000-4 000-ms intervals; severe nerve injury: 200-300-ms stimulus width and 3 000--6 000-ms intervals. Current dosage was 20- 40 mA. The electrical stimulation was given 6 minutes/session, once a day, and 20 days were regarded as one treatment cycle. (2) A TMA-A double-frequent mild-hot therapeutic instrument was used on patients in the decimeter wave group after neurolysis. The therapeutic program was adapted to the early and middle-late phase. In the early phase, the decimeter wave was 10-15 W, 10 minutes/session, once a day; in the middle-late phase, the decimeter wave was 10-30 W, 20 minutes/session, once a day. Twenty days were regarded as one treatment cycle. (3) Patients in the compound physical factor group following neurolysis were treated the same as the decimeter wave group and electrical stimulation group, respectively. The treatment was performed once a day, and 20 days were regarded as one course. (4) Patients in the control group were not administered any physical treatment. MAIN OUTCOME MEASURES: Therapeutic efficacy was comprehensively evaluated based on motor and sensory evaluation criteria (set by Subassociation of Hand Surgery, Chinese Medical Association) at 1, 2, and 3 months after surgery, as well as changes in the electromyogram before and after operation. RESULTS: All 124 patients with peripheral nerve entrapment syndrome were included in the final analysis. One month after surgery, fineness rates in the electrical stimulation group, decimeter wave group, and compound physical factor group were not significantly different from those in the control group (P 〉 0.05). There was also no significant difference between the electrical stimulation group, decimeter wave group, and compound physical factor group (P 〉 0.05). Two months after surgery, fineness rates in the electrical stimulation group and decimeter wave group were not significantly different from the control group (P 〉 0.05). However, fineness rates were higher in the compound physical factor group compared to the other three groups (P 〈 0.05). There was no significant difference between the electrical stimulation group and the decimeter wave group (P 〉 0.05). Three months after operation, fineness rates in the electrical stimulation group, decimeter wave group, and compound physical factor group were higher than the control group (P 〈 0.05). However, there was no significant difference between the electrical stimulation group, decimeter wave group, and compound physical factor group (P 〉 0.05). CONCLUSION: The combination of decimeter wave therapy and electrical stimulation can remarkably shorten the recovery time of peripheral nerve function. The synergistic effect is superior to that of electrical stimulation and decimeter wave alone. This suggests that those two physical factors have synergistic effects on the treatment of peripheral nerve entrapment syndrome.展开更多
Fourteen stream segments were investigated throughout the Xin’an Spring in Shanxi Province, China in 2004. The variation ranges in stream size, current velocity, discharge, dissolved oxygen, and specific conductance ...Fourteen stream segments were investigated throughout the Xin’an Spring in Shanxi Province, China in 2004. The variation ranges in stream size, current velocity, discharge, dissolved oxygen, and specific conductance were large. Twenty-two macroalgae species were found in the stream. Major divisions in terms of species numbers were Chlorophyta (59.1%), Cyanophyta (22.8%), Xanthophyta (9.1%), Rhodophyta (4.5%) and Charophyta (4.5%). The most widespread species, Cladophora rivularis (50.0%), also Oedogonium sp. (42.9%) and Spirogyra sp. (42.9%) were well represented throughout the stream, whereas another 10 species were found in only one sampling site. Total percentage cover varied from <1% to 90%. Red algae Batrachospermum acuatum and the charophytes Chara vulgaris have the highest percentage cover. Among the parameters analyzed, the stream width, specific conductance and dissolved oxygen were the ones that more closely related to the species number and percentage cover of macroalgal communities. The species number of each site was negatively correlated with dissolved oxygen content. The total percentage cover of the macroalgae was negatively correlated with the stream width and the specific conductance.展开更多
The work has made a statistic study of the variations of extremely severe cold winter months in the south of China and general circulation and external forcing factors in preceding periods. The result shows that from ...The work has made a statistic study of the variations of extremely severe cold winter months in the south of China and general circulation and external forcing factors in preceding periods. The result shows that from the current month to the preceding March the subtropical high in the west Pacific is persistently weak or located more to the east and south. When the summer monsoon is weak in East Asia in the year before, the winter monsoon will be strong in the current year in which the extremely severe cold month occurs. The Asian polar vortex expands in the preceding July, August and September and the current winter. The Tibetan Plateau has fewer days of snow cover in the November and December before the cold month occurs. There is less snow in the Tibetan Plateau in the preceding winter / spring of each extremely severe cold month. There are more polar ice in the polar Region Ⅳ for the 11 months before the current February, especially the previous March through August, and in Region Ⅱin January ~ November before the current cold month of December but less ice in Region Ⅲ in March ~ August.展开更多
Consumption-oriented daily life resulted in new forms of consumption spaces in many cities. Among these spaces, shopping malls are significant with their improved physical and social environments for consumption and l...Consumption-oriented daily life resulted in new forms of consumption spaces in many cities. Among these spaces, shopping malls are significant with their improved physical and social environments for consumption and leisure for all the family. One of the important marginalized groups, to whom the mall appeals, are young people. Within this framework, the main purpose of this study is to investigate the consumption and leisure practices and experiences of young people in Turkey from their point of view. Migros, a shopping mall in Ankara, was chosen as the site for this research, where both consumption and leisure practices are overlapping within the same space. The research was carried out through observation and in-depth interviews with 104 teenagers. The results indicated that shopping malls were the main leisure and consumption site for teenagers. Teenagers' choice of malls as their favorite leisure and consumption space were found to be the result of some factors such as restrictions which were provoked by their parents, security concerns, location of the mall, and accessibility and limited financial resources. These factors seemed to lead to restrictions in the choice of places to spend their leisure time and limit the use of leisure spaces other than malls. As a consumer group in the mall space, teenagers had some complaints about the prices of facilities which seemed to be influential on their choices of consumption and leisure practices in the mall environment.展开更多
Lentinus(Basidiomycota,Polyporaceae)species are naturally-occurring mushrooms with nutritional and pharmacological importance.Unlike shiitake Lentinula edodes,a widely cultivated mushroom,Lentinus species are often ig...Lentinus(Basidiomycota,Polyporaceae)species are naturally-occurring mushrooms with nutritional and pharmacological importance.Unlike shiitake Lentinula edodes,a widely cultivated mushroom,Lentinus species are often ignored because they are underutilized and unpopular.However,like shiitake,Lentinus spp.could also be valuable resources of functional food and bioactive compounds.It is therefore of high interest to understand their cultural requirements leading to their efficient biomass production.Thus,this study established the optimal culture conditions for the maximum mycelial growth of seven wild strains under four Lentinus species.Their cultivation potentials were also determined using rice straw and sawdust(7:3 v/v)substrate formulation.Mycelia of all Lentinus strains evaluated favorably grew on coconut water gulaman(local crude agar)and other culture media for specific strain with suitable pH ranging from 5.0 to 8.0.Aeration was not a major physical factor for all Lentinus strains except L.squarrosulus strain 1,which favored sealed condition.Both lighted and dark conditions were found suitable for both strains of L.sajor-caju,L.strigosus strain 2 and L.swartzii whereas both strains of L.squarrosulus and L.strigosus strain 1 favorably grew in lighted condition.However,all Lentinus strains evaluated recorded the highest mycelial growth rates and thick mycelia at 30℃.In terms of fruiting body production,all Lentinus strains demonstrated cultivation potential.The seven Lentinus strains completely colonized the substrate for 18.0-25.6 days and initiated primordia for 21.6-33.5 days.The highest yield(52.5 g bag^(-1))and biological efficiency(10.5%)was recorded in L.strigosus strain 1,whereas the lowest was noted in L.strigosus strain 2 with 21.1 g bag^(-1) yield and 4.2%biological efficiency.L.sajor-caju strain 2 and L.squarrosulus strain 1 showed the widest cap diameter and longest stipe,respectively.The mycelial growth and fruiting body performance of Lentinus may vary depending on species and strains.Altogether,the seven new wild strains of Lentinus can be artificially cultivated by providing the nutritional and physical requirements.展开更多
Saline lakes represent a particularly interesting aquatic environment for harboring high microbial diversity.However,the microbial diversity in different states and locations of saline lake is often overlooked.We stud...Saline lakes represent a particularly interesting aquatic environment for harboring high microbial diversity.However,the microbial diversity in different states and locations of saline lake is often overlooked.We studied for the first time the diversity and relative composition of the microbial communities in the Chagan Lake,NE China,and investigated the dif ferences in microbial species and physical and chemical factors in different geographical localities of the lake.After extracting the total DNA of the sample,we tested the library with the established library,sequenced the qualified library with Illumina HiSeq 2500,and studied the bacterial diversity by 16 S rRNA targeted metagenomics analysis.Results reveal that the highest microbial abundance in Chagan Lake at genus level was Proteobacterium followed by Actinomycetes and Bacteroides.In addition,we compared the microbial composition within the lake using alpha-and beta-diversity indices,showing that both diversity and evenness were the highest in the middle of the lake and lowest in the west of lake areas,and in the upper,middle,and lower depth of water columns,the low water column had the highest species number in the whole water environment,but the dif ference was not significant.We believe that physicochemical factors contribute to the formation of microbial community composition and diversity.In aquaculture industry,it is impossible apply horticulture for making full use of the spatial dif ferences in the microbial composition of the water.Therefore,combining cultured aquatic animal with the most suitable microbial species is a good way to boost the breeding ef fect for greater economic value.展开更多
The paper investigates the robustness and parallel scaling properties of a novel physical factorization preconditioner with algebraic multigrid subsolves in the iterative solution of a cell-centered finite volume disc...The paper investigates the robustness and parallel scaling properties of a novel physical factorization preconditioner with algebraic multigrid subsolves in the iterative solution of a cell-centered finite volume discretization of the threedimensional multi-group radiation diffusion equations.The key idea is to take advantage of a particular kind of block factorization of the resulting system matrix and approximate the left-hand block matrix selectively spurred by parallel processing considerations.The spectral property of the preconditioned matrix is then analyzed.The practical strategy is considered sequentially and in parallel.Finally,numerical results illustrate the numerical robustness,computational efficiency and parallel strong and weak scalabilities over the real-world structured and unstructured coupled problems,showing its competitiveness with many existing block preconditioners.展开更多
基金Project supported by the National Natural Science Foundation of China(Nos.90205016 and 50176055)
文摘A primary jet vectoring using synthetic jet actuators with different exit configurations was investigated, and the main physical factors influencing jet vectoring were analyzed and summarized. The physical factors of the pressure difference, the location and area of the lower pressure region, the component of the synthetic jet momentum and the entrainment ratio of the synthetic jet flow to primary jet flow directly control the vectoring force and the vectoring angle. Three characteristic parameters of the synthetic jet contribute to the pressure difference and the area of the lower pressure region Both the extension step and slope angle of the actuator exit have functions of regulating the location of the lower pressure region, the area of the lower pressure region, and the entrainment ratio of the synthetic jet flow to primary jet flow. The slope angle of the actuator exit has additional functions of regulating the component of the synthetic jet momentum. Based upon analyzing the physical factors of jet vectoring control with synthetic jets, the source variables of the physical factors were established. A preparatory control model of jet vectoring using synthetic jet actuator was presented, and it has the benefit of explaining the efficiency of jet vectoring using synthetic jet actuator with source variables at different values, and it indicates the optimal actuator is taking full advantage of the regulating function.
文摘BACKGROUND: Iatrophysics can improve the velocity of local microcirculation at peripheral nerve injured sites and promote the recovery from injury. Research has shown that simultaneous application of two physical factors has synergistic effects on the recovery of peripheral nerve function. OBJECTIVE: To treat patients that received peripheral nerve entrapment surgery with comprehensive rehabilitation by decimeter wave therapy and electrical stimulation, and to observe the clinical effects of promoting nerve function recovery. DESIGN: Randomized controlled study. SETTINGS: Department of Orthopaedics, the Third Hospital of Baoding; Department of Hand Surgery, the Third Hospital of Hebei Medical University; Woman-Children Healthcare Center, Southern District, Baoding. PARTICIPANTS: A total of 124 patients, who received peripheral nerve entrapment surgery, were selected from the Department of Orthopaedics, the Third Hospital of Baoding between July 2001 and May 2007. All patients met the diagnostic standard of peripheral nerve entrapment syndrome defined by Doctor Chen in 1995. All subjects gave informed consent for treatments and conditions involved. The experiment was approved by a local ethics committee. All patients were randomly divided into four groups: electrical stimulation group, decimeter wave group, compound physical factor group, and control group, with 31 subjects in each group. METHODS: Patients received neurolysis at an appropriate interval after hospitalization. (1) Multi-form wave therapeutic equipment made in China was used to treat patients in the electrical stimulation group after neurolysis. Wave form, stimulus width, interval time, and stimulus intensity were regulated based on the grade of nerve injury. The details were as follows: mild nerve injury: 50-100-ms stimulus width and 1 500-2 000-ms intervals; moderate nerve injury: 100-200-ms stimulus width and 3 000-4 000-ms intervals; severe nerve injury: 200-300-ms stimulus width and 3 000--6 000-ms intervals. Current dosage was 20- 40 mA. The electrical stimulation was given 6 minutes/session, once a day, and 20 days were regarded as one treatment cycle. (2) A TMA-A double-frequent mild-hot therapeutic instrument was used on patients in the decimeter wave group after neurolysis. The therapeutic program was adapted to the early and middle-late phase. In the early phase, the decimeter wave was 10-15 W, 10 minutes/session, once a day; in the middle-late phase, the decimeter wave was 10-30 W, 20 minutes/session, once a day. Twenty days were regarded as one treatment cycle. (3) Patients in the compound physical factor group following neurolysis were treated the same as the decimeter wave group and electrical stimulation group, respectively. The treatment was performed once a day, and 20 days were regarded as one course. (4) Patients in the control group were not administered any physical treatment. MAIN OUTCOME MEASURES: Therapeutic efficacy was comprehensively evaluated based on motor and sensory evaluation criteria (set by Subassociation of Hand Surgery, Chinese Medical Association) at 1, 2, and 3 months after surgery, as well as changes in the electromyogram before and after operation. RESULTS: All 124 patients with peripheral nerve entrapment syndrome were included in the final analysis. One month after surgery, fineness rates in the electrical stimulation group, decimeter wave group, and compound physical factor group were not significantly different from those in the control group (P 〉 0.05). There was also no significant difference between the electrical stimulation group, decimeter wave group, and compound physical factor group (P 〉 0.05). Two months after surgery, fineness rates in the electrical stimulation group and decimeter wave group were not significantly different from the control group (P 〉 0.05). However, fineness rates were higher in the compound physical factor group compared to the other three groups (P 〈 0.05). There was no significant difference between the electrical stimulation group and the decimeter wave group (P 〉 0.05). Three months after operation, fineness rates in the electrical stimulation group, decimeter wave group, and compound physical factor group were higher than the control group (P 〈 0.05). However, there was no significant difference between the electrical stimulation group, decimeter wave group, and compound physical factor group (P 〉 0.05). CONCLUSION: The combination of decimeter wave therapy and electrical stimulation can remarkably shorten the recovery time of peripheral nerve function. The synergistic effect is superior to that of electrical stimulation and decimeter wave alone. This suggests that those two physical factors have synergistic effects on the treatment of peripheral nerve entrapment syndrome.
基金Supported by the National Nature Science Foundation of China (No. 30470118 and 30270119)the Nature Science Foundation of Shanxi Province, China (No. 20021079).
文摘Fourteen stream segments were investigated throughout the Xin’an Spring in Shanxi Province, China in 2004. The variation ranges in stream size, current velocity, discharge, dissolved oxygen, and specific conductance were large. Twenty-two macroalgae species were found in the stream. Major divisions in terms of species numbers were Chlorophyta (59.1%), Cyanophyta (22.8%), Xanthophyta (9.1%), Rhodophyta (4.5%) and Charophyta (4.5%). The most widespread species, Cladophora rivularis (50.0%), also Oedogonium sp. (42.9%) and Spirogyra sp. (42.9%) were well represented throughout the stream, whereas another 10 species were found in only one sampling site. Total percentage cover varied from <1% to 90%. Red algae Batrachospermum acuatum and the charophytes Chara vulgaris have the highest percentage cover. Among the parameters analyzed, the stream width, specific conductance and dissolved oxygen were the ones that more closely related to the species number and percentage cover of macroalgal communities. The species number of each site was negatively correlated with dissolved oxygen content. The total percentage cover of the macroalgae was negatively correlated with the stream width and the specific conductance.
基金Research on short-term climatic prediction systems in China" - a key scientific and technological project in the national 9th f
文摘The work has made a statistic study of the variations of extremely severe cold winter months in the south of China and general circulation and external forcing factors in preceding periods. The result shows that from the current month to the preceding March the subtropical high in the west Pacific is persistently weak or located more to the east and south. When the summer monsoon is weak in East Asia in the year before, the winter monsoon will be strong in the current year in which the extremely severe cold month occurs. The Asian polar vortex expands in the preceding July, August and September and the current winter. The Tibetan Plateau has fewer days of snow cover in the November and December before the cold month occurs. There is less snow in the Tibetan Plateau in the preceding winter / spring of each extremely severe cold month. There are more polar ice in the polar Region Ⅳ for the 11 months before the current February, especially the previous March through August, and in Region Ⅱin January ~ November before the current cold month of December but less ice in Region Ⅲ in March ~ August.
文摘Consumption-oriented daily life resulted in new forms of consumption spaces in many cities. Among these spaces, shopping malls are significant with their improved physical and social environments for consumption and leisure for all the family. One of the important marginalized groups, to whom the mall appeals, are young people. Within this framework, the main purpose of this study is to investigate the consumption and leisure practices and experiences of young people in Turkey from their point of view. Migros, a shopping mall in Ankara, was chosen as the site for this research, where both consumption and leisure practices are overlapping within the same space. The research was carried out through observation and in-depth interviews with 104 teenagers. The results indicated that shopping malls were the main leisure and consumption site for teenagers. Teenagers' choice of malls as their favorite leisure and consumption space were found to be the result of some factors such as restrictions which were provoked by their parents, security concerns, location of the mall, and accessibility and limited financial resources. These factors seemed to lead to restrictions in the choice of places to spend their leisure time and limit the use of leisure spaces other than malls. As a consumer group in the mall space, teenagers had some complaints about the prices of facilities which seemed to be influential on their choices of consumption and leisure practices in the mall environment.
基金This work was funded by the Philippine Council for Health Research and Development, Department of Science and Technology。
文摘Lentinus(Basidiomycota,Polyporaceae)species are naturally-occurring mushrooms with nutritional and pharmacological importance.Unlike shiitake Lentinula edodes,a widely cultivated mushroom,Lentinus species are often ignored because they are underutilized and unpopular.However,like shiitake,Lentinus spp.could also be valuable resources of functional food and bioactive compounds.It is therefore of high interest to understand their cultural requirements leading to their efficient biomass production.Thus,this study established the optimal culture conditions for the maximum mycelial growth of seven wild strains under four Lentinus species.Their cultivation potentials were also determined using rice straw and sawdust(7:3 v/v)substrate formulation.Mycelia of all Lentinus strains evaluated favorably grew on coconut water gulaman(local crude agar)and other culture media for specific strain with suitable pH ranging from 5.0 to 8.0.Aeration was not a major physical factor for all Lentinus strains except L.squarrosulus strain 1,which favored sealed condition.Both lighted and dark conditions were found suitable for both strains of L.sajor-caju,L.strigosus strain 2 and L.swartzii whereas both strains of L.squarrosulus and L.strigosus strain 1 favorably grew in lighted condition.However,all Lentinus strains evaluated recorded the highest mycelial growth rates and thick mycelia at 30℃.In terms of fruiting body production,all Lentinus strains demonstrated cultivation potential.The seven Lentinus strains completely colonized the substrate for 18.0-25.6 days and initiated primordia for 21.6-33.5 days.The highest yield(52.5 g bag^(-1))and biological efficiency(10.5%)was recorded in L.strigosus strain 1,whereas the lowest was noted in L.strigosus strain 2 with 21.1 g bag^(-1) yield and 4.2%biological efficiency.L.sajor-caju strain 2 and L.squarrosulus strain 1 showed the widest cap diameter and longest stipe,respectively.The mycelial growth and fruiting body performance of Lentinus may vary depending on species and strains.Altogether,the seven new wild strains of Lentinus can be artificially cultivated by providing the nutritional and physical requirements.
基金Supported by the National Natural Sciences Foundational of China(No.30972191)the 948 Program from the Ministry of Agriculture of China(No.2014Z34)
文摘Saline lakes represent a particularly interesting aquatic environment for harboring high microbial diversity.However,the microbial diversity in different states and locations of saline lake is often overlooked.We studied for the first time the diversity and relative composition of the microbial communities in the Chagan Lake,NE China,and investigated the dif ferences in microbial species and physical and chemical factors in different geographical localities of the lake.After extracting the total DNA of the sample,we tested the library with the established library,sequenced the qualified library with Illumina HiSeq 2500,and studied the bacterial diversity by 16 S rRNA targeted metagenomics analysis.Results reveal that the highest microbial abundance in Chagan Lake at genus level was Proteobacterium followed by Actinomycetes and Bacteroides.In addition,we compared the microbial composition within the lake using alpha-and beta-diversity indices,showing that both diversity and evenness were the highest in the middle of the lake and lowest in the west of lake areas,and in the upper,middle,and lower depth of water columns,the low water column had the highest species number in the whole water environment,but the dif ference was not significant.We believe that physicochemical factors contribute to the formation of microbial community composition and diversity.In aquaculture industry,it is impossible apply horticulture for making full use of the spatial dif ferences in the microbial composition of the water.Therefore,combining cultured aquatic animal with the most suitable microbial species is a good way to boost the breeding ef fect for greater economic value.
基金supported by the National Natural Science Foundation of China(Grant 11971414)Hunan National Applied Mathematics Center(Grant 2020ZYT003)the Research Foundation of Education Bureau of Hunan(Grant 21B0162).
文摘The paper investigates the robustness and parallel scaling properties of a novel physical factorization preconditioner with algebraic multigrid subsolves in the iterative solution of a cell-centered finite volume discretization of the threedimensional multi-group radiation diffusion equations.The key idea is to take advantage of a particular kind of block factorization of the resulting system matrix and approximate the left-hand block matrix selectively spurred by parallel processing considerations.The spectral property of the preconditioned matrix is then analyzed.The practical strategy is considered sequentially and in parallel.Finally,numerical results illustrate the numerical robustness,computational efficiency and parallel strong and weak scalabilities over the real-world structured and unstructured coupled problems,showing its competitiveness with many existing block preconditioners.