The Middle Jurassic palynomorphs from the Yan'an Formation in Dongsheng region of Nei Monggol, consist of 63 species of fossil spores and pollen grains belonging to 34 genera, of which two species were described a...The Middle Jurassic palynomorphs from the Yan'an Formation in Dongsheng region of Nei Monggol, consist of 63 species of fossil spores and pollen grains belonging to 34 genera, of which two species were described as new. Based on statistical analysis of 3 863 specimens identified in 10 samples from Hantaichuan, Nianpanlianggou and Liugou sections, the sporo-pollen assemblage from the Yan'an Formation in Dongsheng region was established, which is generally characterized by the slight dominance of gymnospermous pollen grains (generally attaining proportion of 51%-54%), whereas the pteridophytic spores reach 46%-49% in abundance. In comparison with those of adjacent regions as well as Eurasia and North America, the present sporo-pollen assemblage is regarded to early Middle Jurassic (corresponding to Bajocian Stage) in geological age. According to the climatic conditions reflected by the palynoflora, the paleoclimate in Dongsheng region is suggested to be warm temperate or subtropical warm and humid during the early Middle Jurassic.展开更多
Single crystalline 3C-SiC epitaxial layers are grown on φ 50mm Si wafers by a new resistively heated CVD/LPCVD system,using SiH_4,C_2H_4 and H_2 as gas precursors.X-ray diffraction and Raman scattering measurements a...Single crystalline 3C-SiC epitaxial layers are grown on φ 50mm Si wafers by a new resistively heated CVD/LPCVD system,using SiH_4,C_2H_4 and H_2 as gas precursors.X-ray diffraction and Raman scattering measurements are used to investigate the crystallinity of the grown films.Electrical properties of the epitaxial 3C-SiC layers with thickness of 1~3μm are measured by Van der Pauw method.The improved Hall mobility reaches the highest value of 470cm 2/(V·s) at the carrier concentration of 7.7×10 17 cm -3 .展开更多
Synchro-epitaxy is introduced and a “two periods epitaxy” process is proposed.The influence of the flows of SiH 4 N 1,N 2,deposition time t 1,t 2,and epitaxial temperature T on epilayer quality (embodied by α)...Synchro-epitaxy is introduced and a “two periods epitaxy” process is proposed.The influence of the flows of SiH 4 N 1,N 2,deposition time t 1,t 2,and epitaxial temperature T on epilayer quality (embodied by α) is reported.The shorter initial inducing time t 1 and larger flows of SiH 4 are,the wider single crystal strips are.But the quality of epilayer may be poor.The optimum conditions are:N 1=13.1~17.5sccm,N 2=7.0~7.88sccm,and t 1=30~50s.The influence of temperature is complex:when T is lower than 980℃,single crystal strips increase with T ;when T is higher than 980℃,single crystal strips decrease with T.It reaches maximum near 980℃.展开更多
Aim To study the relationship between the substrate temperature and the morphology and properties of GaN. Methods\ Applying the hydride chemical vapor deposition method, GaN films were deposited on different kinds of...Aim To study the relationship between the substrate temperature and the morphology and properties of GaN. Methods\ Applying the hydride chemical vapor deposition method, GaN films were deposited on different kinds of substrates, including sapphire, Si(111),Si(100),GaAs and GaP(111) both on the P face and the Ga face. The growth was performed at low temperatures of below 700℃. XRD, Hall measurement, cathodoluminescence (CL) and atomic force microscopy (AFM) were used to characterise the film properties. Results\ It was found that the temperature and the nature of substrate materials influence the layer morphology. Conclusion\ The analysis shows that no apparent relationship exists between the optical properties and layer morphology.展开更多
The refractive indices of disordered (Al xGa 1-x ) 0 51 In 0 49 P,which is grown by low-pressure organometallic vapor phase epitaxy and lattice-matched to GaAs substrate,have been determined by measurin...The refractive indices of disordered (Al xGa 1-x ) 0 51 In 0 49 P,which is grown by low-pressure organometallic vapor phase epitaxy and lattice-matched to GaAs substrate,have been determined by measuring their reflectance spectra when the wavelength ranges between 0 5 to 2 5 micrometer.A single-oscillator dispersion model is used to verify the experiment data and calculate the reflectance spectrum.The refractive indices are used to analyze the waveguide of strain quantum well GaInP/AlGaInP visible laser diode.The simulated far field pattern is consistent with the experimental results very well.展开更多
Thick GaN films were grown on GaN/sapphire template in a vertical HVPE reactor. Various material characterization techniques,including AFM, SEM, XRD, RBS/Channeling, CL, PL, and XPS, were used to characterize these Ga...Thick GaN films were grown on GaN/sapphire template in a vertical HVPE reactor. Various material characterization techniques,including AFM, SEM, XRD, RBS/Channeling, CL, PL, and XPS, were used to characterize these GaN epitaxial films. It was found that stepped/terraced structures appeared on the film surface,which were indicative of a nearly step-flow mode of growth for the HVPE GaN despite the high growth rate. A few hexagonal pits appeared on the surface, which have strong light emission. After being etched in molten KOH, the wavy steps disappeared and hexagonal pits with {1010} facets appeared on the surface. An EPD of only 8 ×10^6cm^-2 shows that the GaN film has few dislocations. Both XRD and RBS channeling indicate the high quality of the GaN thick films. Sharp band-edge emission with a full width at half maximum(FWHM)of 67meV was observed, while the yellow and infrared emissions were also found. These emissions are likely caused by native defects and C and O impurities.展开更多
Wet etching characteristics of cubic GaN (c GaN) thin films grown on GaAs(001) by metalorganic vapor phase epitaxy (MOVPE) are investigated.The samples are etched in HCl,H 3PO 4,KOH aqueous solutions,and molten KOH...Wet etching characteristics of cubic GaN (c GaN) thin films grown on GaAs(001) by metalorganic vapor phase epitaxy (MOVPE) are investigated.The samples are etched in HCl,H 3PO 4,KOH aqueous solutions,and molten KOH at temperatures in the range of 90~300℃.It is found that different solution produces different etch figure on the surfaces of a sample.KOH based solutions produce rectangular pits rather than square pits.The etch pits elongate in 1 0] direction,indicating asymmetric etching behavior in the two orthogonal <110> directions.An explanation based on relative reactivity of the various crystallographic planes is employed to interpret qualitatively the asymmetric etching behavior.In addition,it is found that KOH aqueous solution would be more suitable than molten KOH and the two acids for the evaluation of stacking faults in c GaN epilayers. direction,indicating asymmetric etching behavior in the two orthogonal <110> directions.An explanation based on relative reactivity of the various crystallographic planes is employed to interpret qualitatively the asymmetric etching behavior.In addition,it is found that KOH aqueous solution would be more suitable than molten KOH and the two acids for the evaluation of stacking faults in c GaN epilayers.展开更多
High quality GaN is grown on GaN substrate with stripe pattern by metalorganic chemical vapor deposition by means of epitaxial lateral overgrowth. AFM,wet chemical etching, and TEM experiments show that with a two-ste...High quality GaN is grown on GaN substrate with stripe pattern by metalorganic chemical vapor deposition by means of epitaxial lateral overgrowth. AFM,wet chemical etching, and TEM experiments show that with a two-step ELOG procedure, the propagation of defects under the mask is blocked, and the coherently grown GaN above the window also experiences a drastic reduction in defect density. In addition, a grain boundary is formed at the coalescence boundary of neighboring growth fronts. The extremely low density of threading dislocations within wing regions makes ELOG GaN a potential template for the fabrication of nitride-based lasers with improved performance.展开更多
Pneumatic dilation(PD)is considered to be a safe and effective first line therapy for achalasia.The major adverse event caused by PD is esophageal perforation but an immediate gastrografin test may not always detect a...Pneumatic dilation(PD)is considered to be a safe and effective first line therapy for achalasia.The major adverse event caused by PD is esophageal perforation but an immediate gastrografin test may not always detect a perforation.It has been reported that delayed management of perforation for more than 24 h is associated with high mortality.Surgery is the treatment of choice within 24 h,but the management of delayed perforation remains controversial.Hereby,we report a delayed presentation of intrathoracic esophageal perforation following PD in a 48-year-old woman who suffered from achalasia.She completely recovered after intensive medical care.A review of the literature is also discussed.展开更多
Effects of in situ annealing on the structural and optical properties of Gallium nitride (GaN) layers grown on (0001) sapphire by hydride vapor phase epitaxy (HVPE) are studied. The properties of GaN epilayers a...Effects of in situ annealing on the structural and optical properties of Gallium nitride (GaN) layers grown on (0001) sapphire by hydride vapor phase epitaxy (HVPE) are studied. The properties of GaN epilayers are improved by insitu annealing at growth temperature under ammonia (NH3) atmosphere. X-ray diffraction (XRD) analysis shows that the full width at half maximum (FWHM) of the rocking curves narrows as the annealing time increases. Raman scattering spectroscopy shows that E2 (high) peak positions shift to the low frequency region. Compared to without annealing and epilayers annealed with bulk GaN,the E2 (high) peak position of epilayers becomes closer to that of bulk GaN as the in situ annealing time increases. The biaxial compressive stress decreases after in situ annealing. Photoluminescence (PL) examination agrees well with XRD and Raman scattering analyses. These results suggest that the optical and structural properties of GaN epilayers can be improved by in situ annealing.展开更多
AlN film is deposited on a nanorod ZnO template by metalorganic chemical vapor deposition. Scanning electron microscopy measurements reveal that this film forms a lying nanorod surface. The grazing incidence X- ray di...AlN film is deposited on a nanorod ZnO template by metalorganic chemical vapor deposition. Scanning electron microscopy measurements reveal that this film forms a lying nanorod surface. The grazing incidence X- ray diffraction further proves that it is entirely a wurtzite AIN structure, and the average size of the crystallite grains is about 12nm,which is near the ZnO nanorod diameter (30nm). This means that the nanorod ZnO template can restrict the AlN lateral overgrowth. Additionally, by etching the ZnO template with H2 at high temperatures,we directly achieve epitaxial lift-off during the growth process. Eventually, free-standing AlN nanocrystals are achieved,and the undamaged area is near 1cm × 1cm. We define the growth mechanism as a "grow-etch- merge" process.展开更多
Geometric anisotropy is commonly assumed in the investigation of the spatial variations of geophysical parameters. However, this assumption is not always satisfied in practice. We propose a novel method to determine t...Geometric anisotropy is commonly assumed in the investigation of the spatial variations of geophysical parameters. However, this assumption is not always satisfied in practice. We propose a novel method to determine the anisotropy of geophysical parameters. In the proposed method, the variograms are first normalized in all directions. Then, the normalized samples are fitted by the unit range variation increment(URVI) function to estimate the intensities of the variograms in each direction, from which the anisotropy can be finally determined. The performance of the proposed method is validated using InSAR atmospheric delay measurements over the Shanghai region. The results show that the deviation of the method is 6.4%, and that of the geometric anisotropy-based method is 21.2%. In addition, the computational efficiency of the new method is much higher. Subsequently, the URVI- and the geometric anisotropy-based methods are cross-validated in the cross-validation experiments by using Kriging interpolation. The results demonstrate that the structure functions generated with the proposed method are more accurate and can better refl ect the spatial characteristics of the random fi eld. Therefore, the proposed method, which is more accurate and effi cient to determine the anisotropy than the conventional geometry anisotropy-based method, provides a better foundation to estimate the geophysical parameters of interest.展开更多
Using theoretical analysis, the single-phase gas seepage mathematical model influenced by slippage effects was established. The results show that the pressure of producing wells attenuates more violently than the well...Using theoretical analysis, the single-phase gas seepage mathematical model influenced by slippage effects was established. The results show that the pressure of producing wells attenuates more violently than the wells without slippage effects. The decay rate of reservoir pressure is more violent as the Klinkenherg factor increases. The gas prediction output gradually increases as the Klinenberg factor increases when considering gas slippage effects. Through specific examples, analyzed the law of stope pore pressure and gas output forecast changing in a hypotonic reservoir with slippage effects. The results have great theoretical significance in the study of the law of coal-bed methane migration in hypotonic reservoirs and for the exploitation of coal-bed methane.展开更多
We report the fabrication and characterization of light-emitting diodes based on n-ZnO/p-GaN heterojunctions. The n-type ZnO epilayer is deposited by metalorganic chemical vapor deposition (MOCVD) on a MOCVD grown M...We report the fabrication and characterization of light-emitting diodes based on n-ZnO/p-GaN heterojunctions. The n-type ZnO epilayer is deposited by metalorganic chemical vapor deposition (MOCVD) on a MOCVD grown Mg-doped p-GaN layer to form a p-n heterojunction. During the etching process, the relation between the etching depth and the etching time is linear in a HF and NH4 CI solution of a certain ratio. The etching rates of the SiO2 and ZnO are well controlled,which are essential for device fabrication. The current-voltage relationship of this heterojunction shows a diode-like rectifying behavior. In contrast to previous reports,electroluminescence (EL) emissions are observed by the naked eye at room temperature from the n-ZnO/p-GaN heterojunction under forward-and reverse-bias. The origins of these EL emissions are discussed in comparison with the pho- toluminescence spectra.展开更多
Based on a new type of tunnel configuration model with flue in the top of it, the paper simulated the smoke pervasion when fire happens in this type of tunnel by FDS. The results show that the setting up of the flue o...Based on a new type of tunnel configuration model with flue in the top of it, the paper simulated the smoke pervasion when fire happens in this type of tunnel by FDS. The results show that the setting up of the flue outlet reduces the backing up distance of combustion smoke, and the distance of people fleeing is also shortened. But under this condition the smoke density inside and outside of the two flue outlet increases evidently. However, when the exhausted fans are designed at smoking outlet, the smoke movement is accelerated and almost moved into the upper space. This configuration makes the fire smoke density outside of the flue outlet reduced greatly. When the exhausted velocity increased up to a certain critical level, the smoke concentration outside of the flue outlet will reduce at the value which is no harmonious to people's life. This situation will offer a relatively safe space for people fleeing, and fire rescuing can also be carried out from two directions. Therefore, this tunnel configuration mentioned in this article give a new reference mode for personnel flee, fire rescuing and tunnel maintenance.展开更多
文摘The Middle Jurassic palynomorphs from the Yan'an Formation in Dongsheng region of Nei Monggol, consist of 63 species of fossil spores and pollen grains belonging to 34 genera, of which two species were described as new. Based on statistical analysis of 3 863 specimens identified in 10 samples from Hantaichuan, Nianpanlianggou and Liugou sections, the sporo-pollen assemblage from the Yan'an Formation in Dongsheng region was established, which is generally characterized by the slight dominance of gymnospermous pollen grains (generally attaining proportion of 51%-54%), whereas the pteridophytic spores reach 46%-49% in abundance. In comparison with those of adjacent regions as well as Eurasia and North America, the present sporo-pollen assemblage is regarded to early Middle Jurassic (corresponding to Bajocian Stage) in geological age. According to the climatic conditions reflected by the palynoflora, the paleoclimate in Dongsheng region is suggested to be warm temperate or subtropical warm and humid during the early Middle Jurassic.
文摘Single crystalline 3C-SiC epitaxial layers are grown on φ 50mm Si wafers by a new resistively heated CVD/LPCVD system,using SiH_4,C_2H_4 and H_2 as gas precursors.X-ray diffraction and Raman scattering measurements are used to investigate the crystallinity of the grown films.Electrical properties of the epitaxial 3C-SiC layers with thickness of 1~3μm are measured by Van der Pauw method.The improved Hall mobility reaches the highest value of 470cm 2/(V·s) at the carrier concentration of 7.7×10 17 cm -3 .
文摘Synchro-epitaxy is introduced and a “two periods epitaxy” process is proposed.The influence of the flows of SiH 4 N 1,N 2,deposition time t 1,t 2,and epitaxial temperature T on epilayer quality (embodied by α) is reported.The shorter initial inducing time t 1 and larger flows of SiH 4 are,the wider single crystal strips are.But the quality of epilayer may be poor.The optimum conditions are:N 1=13.1~17.5sccm,N 2=7.0~7.88sccm,and t 1=30~50s.The influence of temperature is complex:when T is lower than 980℃,single crystal strips increase with T ;when T is higher than 980℃,single crystal strips decrease with T.It reaches maximum near 980℃.
文摘Aim To study the relationship between the substrate temperature and the morphology and properties of GaN. Methods\ Applying the hydride chemical vapor deposition method, GaN films were deposited on different kinds of substrates, including sapphire, Si(111),Si(100),GaAs and GaP(111) both on the P face and the Ga face. The growth was performed at low temperatures of below 700℃. XRD, Hall measurement, cathodoluminescence (CL) and atomic force microscopy (AFM) were used to characterise the film properties. Results\ It was found that the temperature and the nature of substrate materials influence the layer morphology. Conclusion\ The analysis shows that no apparent relationship exists between the optical properties and layer morphology.
文摘The refractive indices of disordered (Al xGa 1-x ) 0 51 In 0 49 P,which is grown by low-pressure organometallic vapor phase epitaxy and lattice-matched to GaAs substrate,have been determined by measuring their reflectance spectra when the wavelength ranges between 0 5 to 2 5 micrometer.A single-oscillator dispersion model is used to verify the experiment data and calculate the reflectance spectrum.The refractive indices are used to analyze the waveguide of strain quantum well GaInP/AlGaInP visible laser diode.The simulated far field pattern is consistent with the experimental results very well.
文摘Thick GaN films were grown on GaN/sapphire template in a vertical HVPE reactor. Various material characterization techniques,including AFM, SEM, XRD, RBS/Channeling, CL, PL, and XPS, were used to characterize these GaN epitaxial films. It was found that stepped/terraced structures appeared on the film surface,which were indicative of a nearly step-flow mode of growth for the HVPE GaN despite the high growth rate. A few hexagonal pits appeared on the surface, which have strong light emission. After being etched in molten KOH, the wavy steps disappeared and hexagonal pits with {1010} facets appeared on the surface. An EPD of only 8 ×10^6cm^-2 shows that the GaN film has few dislocations. Both XRD and RBS channeling indicate the high quality of the GaN thick films. Sharp band-edge emission with a full width at half maximum(FWHM)of 67meV was observed, while the yellow and infrared emissions were also found. These emissions are likely caused by native defects and C and O impurities.
文摘Wet etching characteristics of cubic GaN (c GaN) thin films grown on GaAs(001) by metalorganic vapor phase epitaxy (MOVPE) are investigated.The samples are etched in HCl,H 3PO 4,KOH aqueous solutions,and molten KOH at temperatures in the range of 90~300℃.It is found that different solution produces different etch figure on the surfaces of a sample.KOH based solutions produce rectangular pits rather than square pits.The etch pits elongate in 1 0] direction,indicating asymmetric etching behavior in the two orthogonal <110> directions.An explanation based on relative reactivity of the various crystallographic planes is employed to interpret qualitatively the asymmetric etching behavior.In addition,it is found that KOH aqueous solution would be more suitable than molten KOH and the two acids for the evaluation of stacking faults in c GaN epilayers. direction,indicating asymmetric etching behavior in the two orthogonal <110> directions.An explanation based on relative reactivity of the various crystallographic planes is employed to interpret qualitatively the asymmetric etching behavior.In addition,it is found that KOH aqueous solution would be more suitable than molten KOH and the two acids for the evaluation of stacking faults in c GaN epilayers.
文摘High quality GaN is grown on GaN substrate with stripe pattern by metalorganic chemical vapor deposition by means of epitaxial lateral overgrowth. AFM,wet chemical etching, and TEM experiments show that with a two-step ELOG procedure, the propagation of defects under the mask is blocked, and the coherently grown GaN above the window also experiences a drastic reduction in defect density. In addition, a grain boundary is formed at the coalescence boundary of neighboring growth fronts. The extremely low density of threading dislocations within wing regions makes ELOG GaN a potential template for the fabrication of nitride-based lasers with improved performance.
文摘Pneumatic dilation(PD)is considered to be a safe and effective first line therapy for achalasia.The major adverse event caused by PD is esophageal perforation but an immediate gastrografin test may not always detect a perforation.It has been reported that delayed management of perforation for more than 24 h is associated with high mortality.Surgery is the treatment of choice within 24 h,but the management of delayed perforation remains controversial.Hereby,we report a delayed presentation of intrathoracic esophageal perforation following PD in a 48-year-old woman who suffered from achalasia.She completely recovered after intensive medical care.A review of the literature is also discussed.
文摘Effects of in situ annealing on the structural and optical properties of Gallium nitride (GaN) layers grown on (0001) sapphire by hydride vapor phase epitaxy (HVPE) are studied. The properties of GaN epilayers are improved by insitu annealing at growth temperature under ammonia (NH3) atmosphere. X-ray diffraction (XRD) analysis shows that the full width at half maximum (FWHM) of the rocking curves narrows as the annealing time increases. Raman scattering spectroscopy shows that E2 (high) peak positions shift to the low frequency region. Compared to without annealing and epilayers annealed with bulk GaN,the E2 (high) peak position of epilayers becomes closer to that of bulk GaN as the in situ annealing time increases. The biaxial compressive stress decreases after in situ annealing. Photoluminescence (PL) examination agrees well with XRD and Raman scattering analyses. These results suggest that the optical and structural properties of GaN epilayers can be improved by in situ annealing.
文摘AlN film is deposited on a nanorod ZnO template by metalorganic chemical vapor deposition. Scanning electron microscopy measurements reveal that this film forms a lying nanorod surface. The grazing incidence X- ray diffraction further proves that it is entirely a wurtzite AIN structure, and the average size of the crystallite grains is about 12nm,which is near the ZnO nanorod diameter (30nm). This means that the nanorod ZnO template can restrict the AlN lateral overgrowth. Additionally, by etching the ZnO template with H2 at high temperatures,we directly achieve epitaxial lift-off during the growth process. Eventually, free-standing AlN nanocrystals are achieved,and the undamaged area is near 1cm × 1cm. We define the growth mechanism as a "grow-etch- merge" process.
基金sponsored jointly by the National Hi-tech Research and Development Program of China(No.2012AA121301)National Basic Research Program of China(No.2012CB719903)+1 种基金the National Natural Science Foundation of China(Nos.41222027,41474007,and 41404013)Hunan Provincial Natural Science Foundation of China(No.13JJ1006)
文摘Geometric anisotropy is commonly assumed in the investigation of the spatial variations of geophysical parameters. However, this assumption is not always satisfied in practice. We propose a novel method to determine the anisotropy of geophysical parameters. In the proposed method, the variograms are first normalized in all directions. Then, the normalized samples are fitted by the unit range variation increment(URVI) function to estimate the intensities of the variograms in each direction, from which the anisotropy can be finally determined. The performance of the proposed method is validated using InSAR atmospheric delay measurements over the Shanghai region. The results show that the deviation of the method is 6.4%, and that of the geometric anisotropy-based method is 21.2%. In addition, the computational efficiency of the new method is much higher. Subsequently, the URVI- and the geometric anisotropy-based methods are cross-validated in the cross-validation experiments by using Kriging interpolation. The results demonstrate that the structure functions generated with the proposed method are more accurate and can better refl ect the spatial characteristics of the random fi eld. Therefore, the proposed method, which is more accurate and effi cient to determine the anisotropy than the conventional geometry anisotropy-based method, provides a better foundation to estimate the geophysical parameters of interest.
基金Supported by the Youth Program of the National Natural Science Foundation of China (51004061)
文摘Using theoretical analysis, the single-phase gas seepage mathematical model influenced by slippage effects was established. The results show that the pressure of producing wells attenuates more violently than the wells without slippage effects. The decay rate of reservoir pressure is more violent as the Klinkenherg factor increases. The gas prediction output gradually increases as the Klinenberg factor increases when considering gas slippage effects. Through specific examples, analyzed the law of stope pore pressure and gas output forecast changing in a hypotonic reservoir with slippage effects. The results have great theoretical significance in the study of the law of coal-bed methane migration in hypotonic reservoirs and for the exploitation of coal-bed methane.
文摘We report the fabrication and characterization of light-emitting diodes based on n-ZnO/p-GaN heterojunctions. The n-type ZnO epilayer is deposited by metalorganic chemical vapor deposition (MOCVD) on a MOCVD grown Mg-doped p-GaN layer to form a p-n heterojunction. During the etching process, the relation between the etching depth and the etching time is linear in a HF and NH4 CI solution of a certain ratio. The etching rates of the SiO2 and ZnO are well controlled,which are essential for device fabrication. The current-voltage relationship of this heterojunction shows a diode-like rectifying behavior. In contrast to previous reports,electroluminescence (EL) emissions are observed by the naked eye at room temperature from the n-ZnO/p-GaN heterojunction under forward-and reverse-bias. The origins of these EL emissions are discussed in comparison with the pho- toluminescence spectra.
文摘Based on a new type of tunnel configuration model with flue in the top of it, the paper simulated the smoke pervasion when fire happens in this type of tunnel by FDS. The results show that the setting up of the flue outlet reduces the backing up distance of combustion smoke, and the distance of people fleeing is also shortened. But under this condition the smoke density inside and outside of the two flue outlet increases evidently. However, when the exhausted fans are designed at smoking outlet, the smoke movement is accelerated and almost moved into the upper space. This configuration makes the fire smoke density outside of the flue outlet reduced greatly. When the exhausted velocity increased up to a certain critical level, the smoke concentration outside of the flue outlet will reduce at the value which is no harmonious to people's life. This situation will offer a relatively safe space for people fleeing, and fire rescuing can also be carried out from two directions. Therefore, this tunnel configuration mentioned in this article give a new reference mode for personnel flee, fire rescuing and tunnel maintenance.