To improve the anti-oxidation ability of silicon-based coating for carbon/carbon （C/C） composites at high temperatures, a ZrB2 modified silicon-based multilayer oxidation protective coating was prepared by pack ceme...To improve the anti-oxidation ability of silicon-based coating for carbon/carbon （C/C） composites at high temperatures, a ZrB2 modified silicon-based multilayer oxidation protective coating was prepared by pack cementation. The phase composition, microstructure and oxidation resistance at 1773, 1873 and 1953 K in air were investigated. The prepared coating exhibits dense structure and good oxidation protective ability. Due to the formation of stable ZrSiO4-SiO2 compound, the coating can effectively protect C/C composites from oxidation at 1773 K for more than 550 h. The anti-oxidation performance decreases with the increase of oxidation temperature. The mass loss of coated sample is 2.44% after oxidation at 1953 K for 50 h, which is attributed to the decomposition of ZrSiO4 and the volatilization of SiO2 protection layer.展开更多
TiN/TiAlN multilayer coatings were prepared by arc ion plating with separate targets. In order to decrease the unfavorable macroparticles, a straight magnetized filter was used for the low melting aluminium target. Th...TiN/TiAlN multilayer coatings were prepared by arc ion plating with separate targets. In order to decrease the unfavorable macroparticles, a straight magnetized filter was used for the low melting aluminium target. The results show that the output plasmas of titanium target without filter and aluminium target with filter reach the substrate with the same order of magnitude. Meanwhile, the number of macropartieles in TiN/TiAlN multilayer coatings deposited with separate targets is only 1/10-1/3 of that deposited with alloy target reported in literature. Al atom addition may lead to the decrease of peak at （200） lattice plane and strengthening of peak at （111） and （220） lattice planes. The measured hardness of TiN/TiAlN multilayer coatings accords with the mixture principle and the maximum hardness is HV2495. The adhesion strength reaches 75 N.展开更多
C/SiC/MoSi2-SiC-Si oxidation protective multilayer coating for carbon/carbon （C/C） composites was prepared by pack cementation and slurry method. The microstructure, element distribution and phase composition of the...C/SiC/MoSi2-SiC-Si oxidation protective multilayer coating for carbon/carbon （C/C） composites was prepared by pack cementation and slurry method. The microstructure, element distribution and phase composition of the as-received coating were analyzed by scanning electron microscopy （SEM）, energy dispersive X-ray spectroscopy （EDS） and X-ray diffraction （XRD）. The results show that the multilayer coating was composed of MoSi2, SiC and Si. It could effectively protect C/C composites against oxidation for 200 h with the mass loss of 3.25% at 1873 K in static air. The mass loss of the coated C/C composites results from the volatilization of SiO2 and the formation of cracks and bubble holes in the coating.展开更多
A SiC/ZrSiO4？SiO2 （SZS） coating was successfully fabricated on the carbon/carbon （C/C） composites by pack cementation, slurry painting and sintering to improve the anti-oxidation property and thermal shock r...A SiC/ZrSiO4？SiO2 （SZS） coating was successfully fabricated on the carbon/carbon （C/C） composites by pack cementation, slurry painting and sintering to improve the anti-oxidation property and thermal shock resistance. The anti-oxidation properties under different oxygen partial pressures （OPP） and thermal shock resistance of the SZS coating were investigated. The results show that the SZS coated sample under low OPP, corresponding to the ambient air, during isothermal oxidation was 0.54% in mass gain after 111 h oxidation at 1500 ° C and less than 0.03% in mass loss after 50 h oxidation in high OPP, corresponding to the air flow rate of 36 L/h. Additionally, the residual compressive strengths （RCS） of the SZS coated samples after oxidation for 50 h in high OPP and 80 h in low OPP remain about 70% and 72.5% of those of original C/C samples, respectively. Moreover, the mass loss of SZS coated samples subjected to the thermal cycle from 1500 ° C in high OPP to boiling water for 30 times was merely 1.61%.展开更多
Yttrium silicate （Y2Si2O7） coating was fabricated on C/SiC composites through dip-coating with silicone resin ＋ Y2O3 powder slurry as raw materials. The synthesis, microstructure and oxidation resistance and the an...Yttrium silicate （Y2Si2O7） coating was fabricated on C/SiC composites through dip-coating with silicone resin ＋ Y2O3 powder slurry as raw materials. The synthesis, microstructure and oxidation resistance and the anti-oxidation mechanism of Y2Si2O7 coating were investigated. Y2Si2O7 can be synthesized by the pyrolysis of Y2O3 powder filled silicone resin at mass ratio of 54.2：45.8 and 800 °C in air and then heat treated at 1400 °C under Ar. The as-fabricated coating shows high density and favorable bonding to C/SiC composites. After oxidation in air at 1400, 1500 and 1600 °C for 30 min, the coating-containing composites possess 130%-140% of original flexural strength. The desirable thermal stability and the further densification of coating during oxidation are responsible for the excellent oxidation resistance. In addition, the formation of eutectic Y-Si-Al-O glassy phase between Y2Si2O7 and Al2O3 sample bracket at 1500 °C is discovered.展开更多
为了探讨5-甲基胞嘧啶(5-methylcytosine,m5C)相关基因在三阴性乳腺癌(triple negative breast cancer,TNBC)患者治疗及预后中的潜在价值,构建了基于m5C相关基因的预后预测模型,用于评估TNBC患者的预后和生存状况。从基因表达总库(gene ...为了探讨5-甲基胞嘧啶(5-methylcytosine,m5C)相关基因在三阴性乳腺癌(triple negative breast cancer,TNBC)患者治疗及预后中的潜在价值,构建了基于m5C相关基因的预后预测模型,用于评估TNBC患者的预后和生存状况。从基因表达总库(gene expression omnibus,GEO)数据库和癌症基因组图谱(the cancer genome atlas,TCGA)数据库中下载TNBC基因表达谱和相应的临床数据。通过Pearson分析确定了99个m5C相关基因,进一步采用单因素Cox分析鉴定出5个与预后有关的m5C相关基因(SLC6A14、BCL11A、UGT8、LMO4、PSAT1)并构建了风险评分(risk score)预测模型,根据风险评分中位值将患者划分为高风险组和低风险组。使用Kaplan-Meier(K-M)生存分析、受试者工作特征(receiver operating characteristic,ROC)曲线、多变量Cox回归分析、构建列线图和校准曲线评估了模型的预测效能。训练集和验证集的K-M生存曲线、受试者工作特征曲线下面积(area under the curve,AUC)分析均验证了模型具有良好的预测能力。多变量Cox回归分析显示,风险评分可作为独立的预后生物标志物。使用ssGSEA、免疫评分分析和化疗药物对高低风险组患者的半最大抑制浓度(half maximal inhibitory concentration,IC50)值差异分析显示,免疫细胞和免疫检查点基因以及大多数化疗药物的IC50值在不同风险组之间的表达存在显著差异。研究结果构建了基于5个m5C相关基因的风险评分预后预测模型,这将有助于阐明TNBC中m5C相关基因的作用机制,进而提供更有价值的预后及诊断的生物标志物和潜在的治疗靶点,为TNBC患者临床个性化治疗提供理论指导。展开更多
Objective The effect of the functionally unknown gene C6orf120 on autoimmune hepatitis was investigated on C6orf120 knockout rats(C6orf120^(-/-))and THP-1 cells.Method Six–eight-week-old C6orf120^(-/-)and wild-type(W...Objective The effect of the functionally unknown gene C6orf120 on autoimmune hepatitis was investigated on C6orf120 knockout rats(C6orf120^(-/-))and THP-1 cells.Method Six–eight-week-old C6orf120^(-/-)and wild-type(WT)SD rats were injected with Con A(16 mg/kg),and euthanized after 24 h.The sera,livers,and spleens were collected.THP-1 cells and the recombinant protein(rC6ORF120)were used to explore the mechanism in vitro.The frequency of M1 and M2 macrophages was analyzed using flow cytometry.Western blotting and PCR were used to detect macrophage polarization-associated factors.Results C6orf120 knockout attenuated Con A-induced autoimmune hepatitis.Flow cytometry indicated that the proportion of CD68^(+)CD86^(+)M1 macrophages from the liver and spleen in the C6orf120^(-/-)rats decreased.C6orf120 knockout induced downregulation of CD86 protein and the mRNA levels of related inflammatory factors TNF-α,IL-1β,and IL-6 in the liver.C6orf120 knockout did not affect the polarization of THP-1 cells.However,rC6ORF120 promoted the THP-1 cells toward CD68^(+)CD80^(+)M1 macrophages and inhibited the CD68^(+)CD206^(+)M2 phenotype.Conclusion C6orf120 knockout alleviates Con A-induced autoimmune hepatitis by inhibiting macrophage polarization toward M1 macrophages and reducing the expression of related inflammatory factors in C6orf120^(-/-)rats.展开更多
In practical engineering,due to the noncontinuity characteristics of joints in rock slopes,in addition to plane failure,stepped sliding failure may occur for intermittently jointed rock slopes.Especially for intermitt...In practical engineering,due to the noncontinuity characteristics of joints in rock slopes,in addition to plane failure,stepped sliding failure may occur for intermittently jointed rock slopes.Especially for intermittently bedding jointed rock slopes,the correlation and difference in strength parameters between joints and rock bridges,along with the various failure modes and intermittency of rock bridges,contribute to the complexity of stepped failure modes and the unpredictability of failure regions.Based on the upper-bound limit analysis method and multi-sliders step-path failure mode,considering the shear and tensile failure of rock bridges and the weakened relationship between the strength parameters of rock bridges and jointed surfaces,by introducing the modified M-C failure criterion and the formula for calculating the energy consumption of tensile failure of rock bridges,two failure mechanisms are constructed to obtain the safety factor(F_(s))of intermittently jointed rock slopes.The sequential quadratic programming method is used to obtain the optimal upper-bound solution for F_(s).The influence of multiple key parameters(slope height H,horizontal distance L,Slope angleβ,shear strength parameters of the rock bridgeφr and cr,Dimensionless parameter u,weakening coefficients of the internal friction angle and cohesion between the rock bridges and joint surfaces Kφand Kc)on the stability analysis of intermittently jointed rock slopes under the shear failure mode of rock bridges as well as under the tensile failure mode is also explored.The reliability of the failure mechanisms is verified by comparative analysis with theoretical results,numerical results,and landslide cases,and the variation rules of F_(s)with each key parameter are obtained.The results show that F_(s) varies linearly withφr and cr of the rock bridge and with K_(φ)and K_(c),whereas F_(s)changes nonlinearly with H and L.In particular,with the increase in Kφand Kc,Fs increases by approximately 52.78%and 171.02%on average,respectively.For rock bridge tensile failure,F_(s) shows a nonlinearly positive correlation withφr,cr,Kφand Kc.In particular,with the increase in Kφand Kc,Fs increases by approximately 13%and 61.69%on average,respectively.Fs decreases rapidly with increasing slope gradientβand decreasing dimensionless parameterμ.When Kφand Kc are both less than 1.0,the stepped sliding surface occurs more easily than the plane failure surface,especially in the case of tensile failure of the rock bridge.In addition,rock slopes with higher strength parameters,taller heights,and greater weakening coefficients are prone to rock bridge tension failure with lower Fs,and more attention should be given to the occurrence of such accidents in actual engineering.展开更多
In this work,we report observations of three comets:38P/Stephan-Oterma,64P/Swift-Gehrels,and C/2017 M4(ATLAS),conducted with the Nanshan one-meter wide-field telescope in 2018 August and November,and 2019January.We ex...In this work,we report observations of three comets:38P/Stephan-Oterma,64P/Swift-Gehrels,and C/2017 M4(ATLAS),conducted with the Nanshan one-meter wide-field telescope in 2018 August and November,and 2019January.We extracted morphological features through image enhancement techniques and calculated the dust activity parameter,Afρ,along with dust mass loss rates and coma color indices using broadband photometric data.Our morphological analysis uncovered a spectrum of dust characteristics among the observed comets,ranging from a significant twisted structure in comet 38P/Stephan-Oterma’s coma to the regular coma envelope surrounding comet 64P/Swift-Gehrels.The Afρvalues varied between 148.8±0.3 cm for 64P/Swift-Gehrels and1118.5±6.2 cm for C/2017 M4(ATLAS)(measured within a reference aperture radius ofρ=6″),indicating a range from moderate to high activity levels.Dust mass loss rates were estimated from 328.1 kg s^(-1)for comet 64P/Swift-Gehrels to 1395.5 kg s^(-1)for comet C/2017 M4(ATLAS).The color indices of comets 38P/Stephan-Oterma and C/2017 M4(ATLAS)closely resemble the average colors of active short-period comets and active longperiod comets,respectively.In contrast,64P/Swift-Gehrels exhibits a significantly bluer hue than typical Jupiter family comets.展开更多
基金Projects(51221001,50972120)supported by the National Natural Science Foundation of ChinaProject(73-QP-2010)supported by the Research Fund of the State Key Laboratory of Solidification Processing of Northwestern Polytechnical University,ChinaProject(B08040)supported by Program of Introducing Talents of Discipline to Universities,China
文摘To improve the anti-oxidation ability of silicon-based coating for carbon/carbon （C/C） composites at high temperatures, a ZrB2 modified silicon-based multilayer oxidation protective coating was prepared by pack cementation. The phase composition, microstructure and oxidation resistance at 1773, 1873 and 1953 K in air were investigated. The prepared coating exhibits dense structure and good oxidation protective ability. Due to the formation of stable ZrSiO4-SiO2 compound, the coating can effectively protect C/C composites from oxidation at 1773 K for more than 550 h. The anti-oxidation performance decreases with the increase of oxidation temperature. The mass loss of coated sample is 2.44% after oxidation at 1953 K for 50 h, which is attributed to the decomposition of ZrSiO4 and the volatilization of SiO2 protection layer.
基金Projects (50773015, 10775036) supported by the National Natural Science Foundation of China
文摘TiN/TiAlN multilayer coatings were prepared by arc ion plating with separate targets. In order to decrease the unfavorable macroparticles, a straight magnetized filter was used for the low melting aluminium target. The results show that the output plasmas of titanium target without filter and aluminium target with filter reach the substrate with the same order of magnitude. Meanwhile, the number of macropartieles in TiN/TiAlN multilayer coatings deposited with separate targets is only 1/10-1/3 of that deposited with alloy target reported in literature. Al atom addition may lead to the decrease of peak at （200） lattice plane and strengthening of peak at （111） and （220） lattice planes. The measured hardness of TiN/TiAlN multilayer coatings accords with the mixture principle and the maximum hardness is HV2495. The adhesion strength reaches 75 N.
基金Projects(51272213,51221001)supported by the National Natural Science Foundation of ChinaProject(73-QP-2010)supported by the Research Fund of the State Key Laboratory of Solidification Processing(NWPU)Project(B08040)supported by Program of Introducing Talents of Discipline to Universities,China
文摘C/SiC/MoSi2-SiC-Si oxidation protective multilayer coating for carbon/carbon （C/C） composites was prepared by pack cementation and slurry method. The microstructure, element distribution and phase composition of the as-received coating were analyzed by scanning electron microscopy （SEM）, energy dispersive X-ray spectroscopy （EDS） and X-ray diffraction （XRD）. The results show that the multilayer coating was composed of MoSi2, SiC and Si. It could effectively protect C/C composites against oxidation for 200 h with the mass loss of 3.25% at 1873 K in static air. The mass loss of the coated C/C composites results from the volatilization of SiO2 and the formation of cracks and bubble holes in the coating.
基金Project supported by the Nonferrous Metal Oriented Advanced Structural Materials and Manufacturing Cooperative Innovation Center,ChinaProject(51205417)supported by the National Natural Science Foundation of China
文摘A SiC/ZrSiO4？SiO2 （SZS） coating was successfully fabricated on the carbon/carbon （C/C） composites by pack cementation, slurry painting and sintering to improve the anti-oxidation property and thermal shock resistance. The anti-oxidation properties under different oxygen partial pressures （OPP） and thermal shock resistance of the SZS coating were investigated. The results show that the SZS coated sample under low OPP, corresponding to the ambient air, during isothermal oxidation was 0.54% in mass gain after 111 h oxidation at 1500 ° C and less than 0.03% in mass loss after 50 h oxidation in high OPP, corresponding to the air flow rate of 36 L/h. Additionally, the residual compressive strengths （RCS） of the SZS coated samples after oxidation for 50 h in high OPP and 80 h in low OPP remain about 70% and 72.5% of those of original C/C samples, respectively. Moreover, the mass loss of SZS coated samples subjected to the thermal cycle from 1500 ° C in high OPP to boiling water for 30 times was merely 1.61%.
基金Project supported by the Science and Technology Innovative Research Team in Higher Educational Institutions of Hunan Province,ChinaProject(CJ12-01-01)supported by the Innovative Group of National University of Defense Technology,ChinaProject(SAST2015043)supported by the Science Innovation Foundation of Shanghai Academy of Spaceflight Technology,China
文摘Yttrium silicate （Y2Si2O7） coating was fabricated on C/SiC composites through dip-coating with silicone resin ＋ Y2O3 powder slurry as raw materials. The synthesis, microstructure and oxidation resistance and the anti-oxidation mechanism of Y2Si2O7 coating were investigated. Y2Si2O7 can be synthesized by the pyrolysis of Y2O3 powder filled silicone resin at mass ratio of 54.2：45.8 and 800 °C in air and then heat treated at 1400 °C under Ar. The as-fabricated coating shows high density and favorable bonding to C/SiC composites. After oxidation in air at 1400, 1500 and 1600 °C for 30 min, the coating-containing composites possess 130%-140% of original flexural strength. The desirable thermal stability and the further densification of coating during oxidation are responsible for the excellent oxidation resistance. In addition, the formation of eutectic Y-Si-Al-O glassy phase between Y2Si2O7 and Al2O3 sample bracket at 1500 °C is discovered.
文摘为了探讨5-甲基胞嘧啶(5-methylcytosine,m5C)相关基因在三阴性乳腺癌(triple negative breast cancer,TNBC)患者治疗及预后中的潜在价值,构建了基于m5C相关基因的预后预测模型,用于评估TNBC患者的预后和生存状况。从基因表达总库(gene expression omnibus,GEO)数据库和癌症基因组图谱(the cancer genome atlas,TCGA)数据库中下载TNBC基因表达谱和相应的临床数据。通过Pearson分析确定了99个m5C相关基因,进一步采用单因素Cox分析鉴定出5个与预后有关的m5C相关基因(SLC6A14、BCL11A、UGT8、LMO4、PSAT1)并构建了风险评分(risk score)预测模型,根据风险评分中位值将患者划分为高风险组和低风险组。使用Kaplan-Meier(K-M)生存分析、受试者工作特征(receiver operating characteristic,ROC)曲线、多变量Cox回归分析、构建列线图和校准曲线评估了模型的预测效能。训练集和验证集的K-M生存曲线、受试者工作特征曲线下面积(area under the curve,AUC)分析均验证了模型具有良好的预测能力。多变量Cox回归分析显示,风险评分可作为独立的预后生物标志物。使用ssGSEA、免疫评分分析和化疗药物对高低风险组患者的半最大抑制浓度(half maximal inhibitory concentration,IC50)值差异分析显示,免疫细胞和免疫检查点基因以及大多数化疗药物的IC50值在不同风险组之间的表达存在显著差异。研究结果构建了基于5个m5C相关基因的风险评分预后预测模型,这将有助于阐明TNBC中m5C相关基因的作用机制,进而提供更有价值的预后及诊断的生物标志物和潜在的治疗靶点,为TNBC患者临床个性化治疗提供理论指导。
基金supported by the Dengfeng Talent Support Program of Beijing Municipal Administration of Hospitals[Grant No.DFL20221601]the Natural Science Foundation of Beijing[Grant No.7212053]Innovation Team and Talents Cultivation Program of National Administration of Traditional Chinese Medicine[Grant No.ZYYCXTD-C-202006].
文摘Objective The effect of the functionally unknown gene C6orf120 on autoimmune hepatitis was investigated on C6orf120 knockout rats(C6orf120^(-/-))and THP-1 cells.Method Six–eight-week-old C6orf120^(-/-)and wild-type(WT)SD rats were injected with Con A(16 mg/kg),and euthanized after 24 h.The sera,livers,and spleens were collected.THP-1 cells and the recombinant protein(rC6ORF120)were used to explore the mechanism in vitro.The frequency of M1 and M2 macrophages was analyzed using flow cytometry.Western blotting and PCR were used to detect macrophage polarization-associated factors.Results C6orf120 knockout attenuated Con A-induced autoimmune hepatitis.Flow cytometry indicated that the proportion of CD68^(+)CD86^(+)M1 macrophages from the liver and spleen in the C6orf120^(-/-)rats decreased.C6orf120 knockout induced downregulation of CD86 protein and the mRNA levels of related inflammatory factors TNF-α,IL-1β,and IL-6 in the liver.C6orf120 knockout did not affect the polarization of THP-1 cells.However,rC6ORF120 promoted the THP-1 cells toward CD68^(+)CD80^(+)M1 macrophages and inhibited the CD68^(+)CD206^(+)M2 phenotype.Conclusion C6orf120 knockout alleviates Con A-induced autoimmune hepatitis by inhibiting macrophage polarization toward M1 macrophages and reducing the expression of related inflammatory factors in C6orf120^(-/-)rats.
基金supported by the National Natural Science Foundation of China(Nos.52208369,52309138,52209142,51978666)the Department of Science and Technology of Sichuan Province(2023NSFSC0284).
文摘In practical engineering,due to the noncontinuity characteristics of joints in rock slopes,in addition to plane failure,stepped sliding failure may occur for intermittently jointed rock slopes.Especially for intermittently bedding jointed rock slopes,the correlation and difference in strength parameters between joints and rock bridges,along with the various failure modes and intermittency of rock bridges,contribute to the complexity of stepped failure modes and the unpredictability of failure regions.Based on the upper-bound limit analysis method and multi-sliders step-path failure mode,considering the shear and tensile failure of rock bridges and the weakened relationship between the strength parameters of rock bridges and jointed surfaces,by introducing the modified M-C failure criterion and the formula for calculating the energy consumption of tensile failure of rock bridges,two failure mechanisms are constructed to obtain the safety factor(F_(s))of intermittently jointed rock slopes.The sequential quadratic programming method is used to obtain the optimal upper-bound solution for F_(s).The influence of multiple key parameters(slope height H,horizontal distance L,Slope angleβ,shear strength parameters of the rock bridgeφr and cr,Dimensionless parameter u,weakening coefficients of the internal friction angle and cohesion between the rock bridges and joint surfaces Kφand Kc)on the stability analysis of intermittently jointed rock slopes under the shear failure mode of rock bridges as well as under the tensile failure mode is also explored.The reliability of the failure mechanisms is verified by comparative analysis with theoretical results,numerical results,and landslide cases,and the variation rules of F_(s)with each key parameter are obtained.The results show that F_(s) varies linearly withφr and cr of the rock bridge and with K_(φ)and K_(c),whereas F_(s)changes nonlinearly with H and L.In particular,with the increase in Kφand Kc,Fs increases by approximately 52.78%and 171.02%on average,respectively.For rock bridge tensile failure,F_(s) shows a nonlinearly positive correlation withφr,cr,Kφand Kc.In particular,with the increase in Kφand Kc,Fs increases by approximately 13%and 61.69%on average,respectively.Fs decreases rapidly with increasing slope gradientβand decreasing dimensionless parameterμ.When Kφand Kc are both less than 1.0,the stepped sliding surface occurs more easily than the plane failure surface,especially in the case of tensile failure of the rock bridge.In addition,rock slopes with higher strength parameters,taller heights,and greater weakening coefficients are prone to rock bridge tension failure with lower Fs,and more attention should be given to the occurrence of such accidents in actual engineering.
基金supported by the Natural Science Foundation of Xinjiang Uygur Autonomous Region of China(grant No.2021D01B112)Tianshan Talent Training Program through the grant 2023TSYCCX0101。
文摘In this work,we report observations of three comets:38P/Stephan-Oterma,64P/Swift-Gehrels,and C/2017 M4(ATLAS),conducted with the Nanshan one-meter wide-field telescope in 2018 August and November,and 2019January.We extracted morphological features through image enhancement techniques and calculated the dust activity parameter,Afρ,along with dust mass loss rates and coma color indices using broadband photometric data.Our morphological analysis uncovered a spectrum of dust characteristics among the observed comets,ranging from a significant twisted structure in comet 38P/Stephan-Oterma’s coma to the regular coma envelope surrounding comet 64P/Swift-Gehrels.The Afρvalues varied between 148.8±0.3 cm for 64P/Swift-Gehrels and1118.5±6.2 cm for C/2017 M4(ATLAS)(measured within a reference aperture radius ofρ=6″),indicating a range from moderate to high activity levels.Dust mass loss rates were estimated from 328.1 kg s^(-1)for comet 64P/Swift-Gehrels to 1395.5 kg s^(-1)for comet C/2017 M4(ATLAS).The color indices of comets 38P/Stephan-Oterma and C/2017 M4(ATLAS)closely resemble the average colors of active short-period comets and active longperiod comets,respectively.In contrast,64P/Swift-Gehrels exhibits a significantly bluer hue than typical Jupiter family comets.
