Technologies for reducing corn leaf burn caused by foliar spray of urea-ammonium nitrate (UAN) during the early growing season are limited. A field experiment was carried out to evaluate the effects of humic acid on c...Technologies for reducing corn leaf burn caused by foliar spray of urea-ammonium nitrate (UAN) during the early growing season are limited. A field experiment was carried out to evaluate the effects of humic acid on corn leaf burn caused by foliar spray of undiluted UAN solution on corn canopy at Jackson, TN in 2018. Thirteen treatments of the mixtures of UAN and humic acid were evaluated at V6 of corn with different UAN application rates and different UAN/humic acid ratios. Leaf burn during 1 2, 3, 4, 5, 6, 7, and 14 days after UAN foliar spray significantly differed between with or without humic acid addition. The addition of humic acid to UAN significantly reduced leaf burn at each UAN application rate (15, 25, and 35 gal/acre). The reduction of leaf burn was enhanced as the humic acid/UAN ratio went up from 10% to 30%. Leaf burn due to foliar application of UAN became severer with higher UAN rates. The linear regression of leaf burn 14 days after application with humic acid/UAN ratio was highly significant and negative. However, the linear regression of leaf burn 14 days after application with the UAN application rate was highly significant and positive. In conclusion, adding humic acid to foliar-applied UAN is beneficial for reducing corn leaf burn during the early growing season.展开更多
Zeolite synthesized from fly ash (ZFA) without modification is not efficient for the purification of NH4+ and phosphate at low concentrations that occur in real effluents, despite the high potential removal capacit...Zeolite synthesized from fly ash (ZFA) without modification is not efficient for the purification of NH4+ and phosphate at low concentrations that occur in real effluents, despite the high potential removal capacity. To develop an effective technique to enhance the removal efficiency of ammonium and phosphate at low concentrations, ZFA was modified with acid treatment and the simultaneous removal of ammonium and phosphate in a wide range of concentration was investigated. It was seen that when compared with untreated ZFA, only the treatment by 0.01 mol/L of H2SO4 significantly improved the removal efficiency of ammonium at low initial concentrations. The behavior was well explained by the pH effect. Treatment by more concentrated H2SO4 led to the deterioration of the ZFA structure and a decrease in the cation exchange capacity. Treatment by 0.01 mol/L H2SO4 improved the removal efficiency of phosphate by ZFA at all initial P concentrations, while the treatment by concentrated H2SO4 (≥0.9 mol/L) resulted in a limited maximum phosphate immobilization capacity (PIC). It was concluded that through a previous mild acid treatment (e.g. 0.01 mol/L of H2SO4), ZFA can be used in the simultaneous removal of NH4+ and P at low concentrations simulating real effluent.展开更多
The cytotoxicities of single-walled carbon nanotubes (SWNTs) and acid purified single-walled carbon nanotubes (SWNT-COOH) were investigated by spectroscopic analysis. Cell viability and cell apoptosis were applied...The cytotoxicities of single-walled carbon nanotubes (SWNTs) and acid purified single-walled carbon nanotubes (SWNT-COOH) were investigated by spectroscopic analysis. Cell viability and cell apoptosis were applied to assessing the cytotoxicity of SWNT-COOH, cetyltrimethyl ammonium bromide (CTAB) and acid purified carbon nanotubes modified with cetyltrimethyl ammonium bromide (SWNT-COOH/CTAB). The results indicate that SWNTs are more toxic than SWNT-COOH. Concentration and time-curve analyses indicate that cytotoxicity of SWNT-COOH/CTAB is more related to the toxicity of the surfactant CTAB. The cytotoxicity effect of CTAB and SWNT-COOH/CTAB is acceptable at low concentrations (0.5-25μg/mL). The cytotoxicity observation suggests that SWNT-COOH/CTAB can safely applied to biomedical field at low concentrations (0.5-25μg/mL).展开更多
Citric acid was used to selectively extract cobalt from limonite-type laterite ores in the presence of ammonium bifluoride.The results show that ammonium bifluoride enhances the leaching of cobalt by citric acid,and 8...Citric acid was used to selectively extract cobalt from limonite-type laterite ores in the presence of ammonium bifluoride.The results show that ammonium bifluoride enhances the leaching of cobalt by citric acid,and 84.5% cobalt is extracted from a laterite ore containing 0.13% Co when leached at ambient temperature for 2 h with 30 g/L citric acid and 10 g/L ammonium bifluoride.Pyrolusite is reduced by citric acid during leaching,cobalt intergrown with which is liberated and subsequently chelated by the citric acid.The extraction of cobalt is enhanced in the presence of ammonium bifluoride because the matrix of silicate minerals is destroyed by ammonium bifluoride and the adsorbed cobalt is subsequently liberated.展开更多
A new energetic complex, Ni(3,4'-Hbpt)2(Hoba)2(H20)2 (3,4'-Hbpt = 3-(3-pyridyl)- 5-(4'-pyridyl)-l-H-l,2,4-triazole and H2oba = 4,4'-oxybis(benzoic acid)), has been synthesized by hydrothermal reactio...A new energetic complex, Ni(3,4'-Hbpt)2(Hoba)2(H20)2 (3,4'-Hbpt = 3-(3-pyridyl)- 5-(4'-pyridyl)-l-H-l,2,4-triazole and H2oba = 4,4'-oxybis(benzoic acid)), has been synthesized by hydrothermal reaction and characterized by elemental analysis, IR spectroscopy, single-crystal X-ray diffraction, thermogravimetric analyses and X-ray powder diffraction. Single-crystal X-ray diffraction analysis indicates that the complex belongs to the monoclinic system, space group P2j/c with a = 10.2357(9), b = 24.594(2), c = 10.4225(9)/k, β = 114.0110(10)°, V = 2396.7(4) A3, Dc = 1.460 g/cm3,μ = 0.482 mm-1, Mr = 1053.63, F(000) = 1088, Z = 2, the final R = 0.0358 and wR = 0.0973 with I 〉 2σ(I). Both 3,4'-Hbpt and H2oba ligands adopt monodentate modes linking one Ni(II) ion to form a 0D motif. Furthermore, the 0D motifs are linked into a 3D supramolecular architecture with hydrogen bonds. In addition, the catalytic performance for thermal decomposition of the efficacy of ammonium perchlorate (AP) is explored by differential scanning calorimetry (DSC), which indicates that the complex is a good candidate for a promoter of the thermal decomposition of ammonium perchlorate.展开更多
Four novel gemini quaternary ammonium surfactants containing DSD acid-triazine structure were synthesized using a facile three-step synthetic route , from 4,4'-diamino-2,2'-disulfonic-stilbene (DSD acid), cyan...Four novel gemini quaternary ammonium surfactants containing DSD acid-triazine structure were synthesized using a facile three-step synthetic route , from 4,4'-diamino-2,2'-disulfonic-stilbene (DSD acid), cyanuric chloride and dimethyl dodecylamine. The structures and optical properties of compounds (6a-d) were characterized by Fourier-Transform infrared (FT-IR) spectroscopy, UV-visible absorption spectra and fluorescence emission spectrum. The surface tension and the Critical Micelle Concentration (CMC) were evaluated. The result shows that the four compounds at lower concentrations can greatly reduce the surface tension of aqueous solutions. The spectroscopic properties of? these quaternary ammonium salts are assessed for their effectiveness and potential as fluorescent brightening agents.展开更多
Ammonium 5-sulfosalicylic acid monohydrate (NH4·C7H5O6S·H2O, ASSA) was synthesized and optical grade crystal with dimensions of 45ram × 20mm × 18mm was obtained from aqueous solution by the cooli...Ammonium 5-sulfosalicylic acid monohydrate (NH4·C7H5O6S·H2O, ASSA) was synthesized and optical grade crystal with dimensions of 45ram × 20mm × 18mm was obtained from aqueous solution by the cooling solution method. The crystal structure was confirmed by X-ray single-crystal diffraction method and the empirical composition is C7HIINO7S with formula weight 253.23. The crystal belongs to monoclinic space group P21/c with a = 1 1.884(9), b = 7.306(5), c = 12.152(9) A, β = 104.851(13)°, V= 1019.8(13) A3, Z = 4, Dc = 1.649 g/cm3,μ = 0.340 mm-1, F(000) =528, the final R= 0.0307 and wR= 0.0866 for 7494 observed reflections (I〉 2σ(I)), Elemental analysis, 1R and 1H-NMR spectrum were used to characterize the compound. Thermal analysis showed that one coordination water molecule was contained and dehydration temperature of ASSA crystal was 106℃. Optical transmission and fluorescence spectrum revealed that the ASSA crystal exhibited a strong absorption in ultraviolet region with the sharp absorption edge located at 340 nm and a significant blue fluorescent emission band at 442 nm.展开更多
The distribution and variations of ammonium and the ammonia neutralization effect on acid rain were examined in East Asia during the period of 2000 05 using observed wet deposition data from the Acid Deposition Monito...The distribution and variations of ammonium and the ammonia neutralization effect on acid rain were examined in East Asia during the period of 2000 05 using observed wet deposition data from the Acid Deposition Monitoring Network in East Asia (EANET).Observational trends show a high proportion of NH 4 + in the total cations,with a six-year mean proportion of over 20% for continental and inland regions.The concentrations and deposition of NH 4 + were higher in western China and Vietnam than in other regions.The annual variations in NH 4 + concentration were smooth in most of the regions,except for southern China and Vietnam,where the NH 4 + concentrations increased,and western China,where the NH 4 + concentrations decreased.The neutralization factors (NFs) of NH 4 + indicate that ammonia has a great neutralization capability toward acid rain,including for the regions with low NH 4 + concentrations,such as Japan.The NFs were high in summer,with no obvious discrepancies between the northern and southern stations.However,the correlation coefficients between NH 4 + concentrations and rain pH values imply that the ammonia neutralization effects on the pH values were distinct only at southern China and southern Japan stations.The neutralization of precipitation by ammonia was estimated by comparing the discrepancies between the observed pH values and the pH values calculated without ammonia consuming the H + in NH 4 +.The results demonstrate that ammonia may increase annual mean pH values by 0.4 0.7 in southern China and by 0.15 0.25 in southern Japan.展开更多
The solubility of natural hemimorphite in ammonium sulfate solution was measured by isothermal solution method at 25 °C and the dissolved residue of hemimorphite was investigated by X-ray powder diffraction (XRD...The solubility of natural hemimorphite in ammonium sulfate solution was measured by isothermal solution method at 25 °C and the dissolved residue of hemimorphite was investigated by X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) methods. The results show that zinc and silica in hemimorphite simultaneously dissolve in ammonium sulfate solution. The solubility of zinc in solution increases rapidly from 4.5381 mmol/kg in 0.5469 mol/kg ammonium sulfate solution to 11.5083 mmol/kg in 3.7038 mol/kg ammonium sulfate solution. The solubility of silica in solution increases slowly from 2.5509 mmol/kg in 0.5469 mol/kg ammonium sulfate solution to 7.2891 mmol/kg in 3.7038 mol/kg ammonium sulfate solution. The dissolved residue is the characteristic of hemimorphite Zn4Si2O7(OH)2·H2O based on the results of the XRD, SEM and FTIR. Thus, no phase transition occurs in the dissolution process of hemimorphite in ammonium sulfate solution.展开更多
Background:Dual-energy computed tomography(DECT)is purported to accurately distinguish uric acid stones from non-uric acid stones.However,whether DECT can accurately discriminate ammonium urate stones from uric acid s...Background:Dual-energy computed tomography(DECT)is purported to accurately distinguish uric acid stones from non-uric acid stones.However,whether DECT can accurately discriminate ammonium urate stones from uric acid stones remains unknown.Therefore,we aimed to explore whether they can be accurately identified by DECT and to develop a radiomics model to assist in distinguishing them.Methods:This research included two steps.For the first purpose to evaluate the accuracy of DECT in the diagnosis of uric acid stones,178 urolithiasis patients who underwent preoperative DECT between September 2016 and December 2019 were enrolled.For model construction,93,40,and 109 eligible urolithiasis patients treated between February 2013 and October 2022 were assigned to the training,internal validation,and external validation sets,respectively.Radiomics features were extracted from non-contrast CT images,and the least absolute shrinkage and selection operator(LASSO)algorithm was used to develop a radiomics signature.Then,a radiomics model incorporating the radiomics signature and clinical predictors was constructed.The performance of the model(discrimination,calibration,and clinical usefulness)was evaluated.Results:When patients with ammonium urate stones were included in the analysis,the accuracy of DECT in the diagnosis of uric acid stones was significantly decreased.Sixty-two percent of ammonium urate stones were mistakenly diagnosed as uric acid stones by DECT.A radiomics model incorporating the radiomics signature,urine pH value,and urine white blood cell count was constructed.The model achieved good calibration and discrimination{area under the receiver operating characteristic curve(AUC;95%confidence interval[CI]),0.944(0.899-0.989)},which was internally and externally validated with AUCs of 0.895(95%CI,0.796-0.995)and 0.870(95%CI,0.769-0.972),respectively.Decision curve analysis revealed the clinical usefulness of the model.Conclusions:DECT cannot accurately differentiate ammonium urate stones from uric acid stones.Our proposed radiomics model can serve as a complementary diagnostic tool for distinguishing them in vivo.展开更多
文摘Technologies for reducing corn leaf burn caused by foliar spray of urea-ammonium nitrate (UAN) during the early growing season are limited. A field experiment was carried out to evaluate the effects of humic acid on corn leaf burn caused by foliar spray of undiluted UAN solution on corn canopy at Jackson, TN in 2018. Thirteen treatments of the mixtures of UAN and humic acid were evaluated at V6 of corn with different UAN application rates and different UAN/humic acid ratios. Leaf burn during 1 2, 3, 4, 5, 6, 7, and 14 days after UAN foliar spray significantly differed between with or without humic acid addition. The addition of humic acid to UAN significantly reduced leaf burn at each UAN application rate (15, 25, and 35 gal/acre). The reduction of leaf burn was enhanced as the humic acid/UAN ratio went up from 10% to 30%. Leaf burn due to foliar application of UAN became severer with higher UAN rates. The linear regression of leaf burn 14 days after application with humic acid/UAN ratio was highly significant and negative. However, the linear regression of leaf burn 14 days after application with the UAN application rate was highly significant and positive. In conclusion, adding humic acid to foliar-applied UAN is beneficial for reducing corn leaf burn during the early growing season.
基金Project supported by the Chinese Ministry of Science and Technology Funding (No. 2002AA601013).
文摘Zeolite synthesized from fly ash (ZFA) without modification is not efficient for the purification of NH4+ and phosphate at low concentrations that occur in real effluents, despite the high potential removal capacity. To develop an effective technique to enhance the removal efficiency of ammonium and phosphate at low concentrations, ZFA was modified with acid treatment and the simultaneous removal of ammonium and phosphate in a wide range of concentration was investigated. It was seen that when compared with untreated ZFA, only the treatment by 0.01 mol/L of H2SO4 significantly improved the removal efficiency of ammonium at low initial concentrations. The behavior was well explained by the pH effect. Treatment by more concentrated H2SO4 led to the deterioration of the ZFA structure and a decrease in the cation exchange capacity. Treatment by 0.01 mol/L H2SO4 improved the removal efficiency of phosphate by ZFA at all initial P concentrations, while the treatment by concentrated H2SO4 (≥0.9 mol/L) resulted in a limited maximum phosphate immobilization capacity (PIC). It was concluded that through a previous mild acid treatment (e.g. 0.01 mol/L of H2SO4), ZFA can be used in the simultaneous removal of NH4+ and P at low concentrations simulating real effluent.
基金Project(81172546)supported by the National Natural Science Foundation of ChinaProject(20120162110078)supported by Doctoral Fund of Ministry of Education of China+1 种基金Project(2011ssxp198)supported by the Graduate Degree Thesis Innovation Foundation of Central South University,ChinaProject(13JJ2015)supported by Hunan Provincial Natural Science Foundation of China
文摘The cytotoxicities of single-walled carbon nanotubes (SWNTs) and acid purified single-walled carbon nanotubes (SWNT-COOH) were investigated by spectroscopic analysis. Cell viability and cell apoptosis were applied to assessing the cytotoxicity of SWNT-COOH, cetyltrimethyl ammonium bromide (CTAB) and acid purified carbon nanotubes modified with cetyltrimethyl ammonium bromide (SWNT-COOH/CTAB). The results indicate that SWNTs are more toxic than SWNT-COOH. Concentration and time-curve analyses indicate that cytotoxicity of SWNT-COOH/CTAB is more related to the toxicity of the surfactant CTAB. The cytotoxicity effect of CTAB and SWNT-COOH/CTAB is acceptable at low concentrations (0.5-25μg/mL). The cytotoxicity observation suggests that SWNT-COOH/CTAB can safely applied to biomedical field at low concentrations (0.5-25μg/mL).
基金Project(50725416) supported by the National Natural Science Foundation of China for Distinguished Young Scholars
文摘Citric acid was used to selectively extract cobalt from limonite-type laterite ores in the presence of ammonium bifluoride.The results show that ammonium bifluoride enhances the leaching of cobalt by citric acid,and 84.5% cobalt is extracted from a laterite ore containing 0.13% Co when leached at ambient temperature for 2 h with 30 g/L citric acid and 10 g/L ammonium bifluoride.Pyrolusite is reduced by citric acid during leaching,cobalt intergrown with which is liberated and subsequently chelated by the citric acid.The extraction of cobalt is enhanced in the presence of ammonium bifluoride because the matrix of silicate minerals is destroyed by ammonium bifluoride and the adsorbed cobalt is subsequently liberated.
基金Supported by the National Natural Science Foundation of China(No.21263019)
文摘A new energetic complex, Ni(3,4'-Hbpt)2(Hoba)2(H20)2 (3,4'-Hbpt = 3-(3-pyridyl)- 5-(4'-pyridyl)-l-H-l,2,4-triazole and H2oba = 4,4'-oxybis(benzoic acid)), has been synthesized by hydrothermal reaction and characterized by elemental analysis, IR spectroscopy, single-crystal X-ray diffraction, thermogravimetric analyses and X-ray powder diffraction. Single-crystal X-ray diffraction analysis indicates that the complex belongs to the monoclinic system, space group P2j/c with a = 10.2357(9), b = 24.594(2), c = 10.4225(9)/k, β = 114.0110(10)°, V = 2396.7(4) A3, Dc = 1.460 g/cm3,μ = 0.482 mm-1, Mr = 1053.63, F(000) = 1088, Z = 2, the final R = 0.0358 and wR = 0.0973 with I 〉 2σ(I). Both 3,4'-Hbpt and H2oba ligands adopt monodentate modes linking one Ni(II) ion to form a 0D motif. Furthermore, the 0D motifs are linked into a 3D supramolecular architecture with hydrogen bonds. In addition, the catalytic performance for thermal decomposition of the efficacy of ammonium perchlorate (AP) is explored by differential scanning calorimetry (DSC), which indicates that the complex is a good candidate for a promoter of the thermal decomposition of ammonium perchlorate.
文摘Four novel gemini quaternary ammonium surfactants containing DSD acid-triazine structure were synthesized using a facile three-step synthetic route , from 4,4'-diamino-2,2'-disulfonic-stilbene (DSD acid), cyanuric chloride and dimethyl dodecylamine. The structures and optical properties of compounds (6a-d) were characterized by Fourier-Transform infrared (FT-IR) spectroscopy, UV-visible absorption spectra and fluorescence emission spectrum. The surface tension and the Critical Micelle Concentration (CMC) were evaluated. The result shows that the four compounds at lower concentrations can greatly reduce the surface tension of aqueous solutions. The spectroscopic properties of? these quaternary ammonium salts are assessed for their effectiveness and potential as fluorescent brightening agents.
基金carried out under the sponsorship and financial support from the Key Laboratory of Optoelectronic Materials Chemistry and Physics,Chinese Academy of Sciences
文摘Ammonium 5-sulfosalicylic acid monohydrate (NH4·C7H5O6S·H2O, ASSA) was synthesized and optical grade crystal with dimensions of 45ram × 20mm × 18mm was obtained from aqueous solution by the cooling solution method. The crystal structure was confirmed by X-ray single-crystal diffraction method and the empirical composition is C7HIINO7S with formula weight 253.23. The crystal belongs to monoclinic space group P21/c with a = 1 1.884(9), b = 7.306(5), c = 12.152(9) A, β = 104.851(13)°, V= 1019.8(13) A3, Z = 4, Dc = 1.649 g/cm3,μ = 0.340 mm-1, F(000) =528, the final R= 0.0307 and wR= 0.0866 for 7494 observed reflections (I〉 2σ(I)), Elemental analysis, 1R and 1H-NMR spectrum were used to characterize the compound. Thermal analysis showed that one coordination water molecule was contained and dehydration temperature of ASSA crystal was 106℃. Optical transmission and fluorescence spectrum revealed that the ASSA crystal exhibited a strong absorption in ultraviolet region with the sharp absorption edge located at 340 nm and a significant blue fluorescent emission band at 442 nm.
基金supported by the NationalBasic Research Program of China (Grant No. 2005CB422205)
文摘The distribution and variations of ammonium and the ammonia neutralization effect on acid rain were examined in East Asia during the period of 2000 05 using observed wet deposition data from the Acid Deposition Monitoring Network in East Asia (EANET).Observational trends show a high proportion of NH 4 + in the total cations,with a six-year mean proportion of over 20% for continental and inland regions.The concentrations and deposition of NH 4 + were higher in western China and Vietnam than in other regions.The annual variations in NH 4 + concentration were smooth in most of the regions,except for southern China and Vietnam,where the NH 4 + concentrations increased,and western China,where the NH 4 + concentrations decreased.The neutralization factors (NFs) of NH 4 + indicate that ammonia has a great neutralization capability toward acid rain,including for the regions with low NH 4 + concentrations,such as Japan.The NFs were high in summer,with no obvious discrepancies between the northern and southern stations.However,the correlation coefficients between NH 4 + concentrations and rain pH values imply that the ammonia neutralization effects on the pH values were distinct only at southern China and southern Japan stations.The neutralization of precipitation by ammonia was estimated by comparing the discrepancies between the observed pH values and the pH values calculated without ammonia consuming the H + in NH 4 +.The results demonstrate that ammonia may increase annual mean pH values by 0.4 0.7 in southern China and by 0.15 0.25 in southern Japan.
基金supported by the National Natural Science Foundation of the People’s Republic of China“Data-driven high-throughput screening of cathode materials for Zn-ion batteries”(22065032)Undergraduate Education and Teaching Research and Reform Project of Universities in Xinjiang Uygur Autonomous Region“Innovative research on ideological and political education in courses and virtual simulation technology in structural chemistry”(XJGXPTJG-202205).
基金Foundation item:Project(2007CB613601)supported by the National Basic Research and Development Program of ChinaProject(511340071)supported by the National Natural Science Foundation of China
文摘The solubility of natural hemimorphite in ammonium sulfate solution was measured by isothermal solution method at 25 °C and the dissolved residue of hemimorphite was investigated by X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) methods. The results show that zinc and silica in hemimorphite simultaneously dissolve in ammonium sulfate solution. The solubility of zinc in solution increases rapidly from 4.5381 mmol/kg in 0.5469 mol/kg ammonium sulfate solution to 11.5083 mmol/kg in 3.7038 mol/kg ammonium sulfate solution. The solubility of silica in solution increases slowly from 2.5509 mmol/kg in 0.5469 mol/kg ammonium sulfate solution to 7.2891 mmol/kg in 3.7038 mol/kg ammonium sulfate solution. The dissolved residue is the characteristic of hemimorphite Zn4Si2O7(OH)2·H2O based on the results of the XRD, SEM and FTIR. Thus, no phase transition occurs in the dissolution process of hemimorphite in ammonium sulfate solution.
基金supported by the China Postdoctoral Science Foundation(Nos.2021TQ0387,2022M713625,and 2021M703709)the National Natural Science Foundation of China(Nos.82203188 and 81825016)+1 种基金Guangdong Provincial Clinical Research Center for Urological Diseases(No.2020B1111170006)the Guangdong Basic and Applied Basic Research Foundation(No.2020A1515111119)
文摘Background:Dual-energy computed tomography(DECT)is purported to accurately distinguish uric acid stones from non-uric acid stones.However,whether DECT can accurately discriminate ammonium urate stones from uric acid stones remains unknown.Therefore,we aimed to explore whether they can be accurately identified by DECT and to develop a radiomics model to assist in distinguishing them.Methods:This research included two steps.For the first purpose to evaluate the accuracy of DECT in the diagnosis of uric acid stones,178 urolithiasis patients who underwent preoperative DECT between September 2016 and December 2019 were enrolled.For model construction,93,40,and 109 eligible urolithiasis patients treated between February 2013 and October 2022 were assigned to the training,internal validation,and external validation sets,respectively.Radiomics features were extracted from non-contrast CT images,and the least absolute shrinkage and selection operator(LASSO)algorithm was used to develop a radiomics signature.Then,a radiomics model incorporating the radiomics signature and clinical predictors was constructed.The performance of the model(discrimination,calibration,and clinical usefulness)was evaluated.Results:When patients with ammonium urate stones were included in the analysis,the accuracy of DECT in the diagnosis of uric acid stones was significantly decreased.Sixty-two percent of ammonium urate stones were mistakenly diagnosed as uric acid stones by DECT.A radiomics model incorporating the radiomics signature,urine pH value,and urine white blood cell count was constructed.The model achieved good calibration and discrimination{area under the receiver operating characteristic curve(AUC;95%confidence interval[CI]),0.944(0.899-0.989)},which was internally and externally validated with AUCs of 0.895(95%CI,0.796-0.995)and 0.870(95%CI,0.769-0.972),respectively.Decision curve analysis revealed the clinical usefulness of the model.Conclusions:DECT cannot accurately differentiate ammonium urate stones from uric acid stones.Our proposed radiomics model can serve as a complementary diagnostic tool for distinguishing them in vivo.