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Humic Acid Effects on Reducing Corn Leaf Burn Caused by Foliar Spray of Urea-Ammonium Nitrate at Different Humic Acid/Urea-Ammonium Nitrate Ratios
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作者 Xinhua Yin 《Open Journal of Soil Science》 2024年第3期180-189,共10页
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
关键词 Humic acid Urea-ammonium Nitrate CORN Leaf Burn N rate Ratio
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Simultaneous removal of ammonium and phosphate by zeolite synthesized from coal fly ash as influenced by acid treatment 被引量:33
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作者 ZHANG Bao-hua WU De-yi WANG Chong HE Sheng-bing ZHANG Zhen-jia KONG Hai-nan 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2007年第5期540-545,共6页
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
关键词 ZEOLITE fly ash acid treatment ammonium PHOSPHATE REMOVAL
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Cytotoxicity effect assessment of acid purified carbon nanotubes modified with cetyltrimethyl ammonium bromide
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作者 甘丽 阎雪彬 +4 位作者 杨金凤 谷永红 黄东 章饶香 黄利华 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2013年第11期3346-3352,共7页
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
关键词 single-walled carbon nanotube cetyltrimethyl ammonium bromide CYTOTOXICITY acid purification APOPTOSIS
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Extraction of cobalt from laterite ores by citric acid in presence of ammonium bifluoride 被引量:3
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作者 李光辉 饶明军 +2 位作者 李骞 彭志伟 姜涛 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2010年第8期1517-1520,共4页
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
关键词 LATERITE COBALT citric acid ammonium bifluoride
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A New Nickel(Ⅱ) Coordination Compound Constructed by Pyridyl-triazole and Oxybis(Benzoic Acid): Synthesis,Crystal Structure and the Effect on the Thermal Decomposition of Ammonium Perchlorate 被引量:5
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作者 韩晶 李婷 李冰 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 2015年第2期253-259,共7页
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
关键词 3-(3-pyridyl)-5-(4'-pyridyl)-l-H-l 2 4-triazole 4 4'-oxybis(benzoic acid crystal structure thermal decomposition ammonium perchlorate
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Synthesis, Optical and Surface Properties of the New Gemini Quaternary Ammonium Surfactants Containing DSD Acid-triazine Structure 被引量:1
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作者 Maosheng Wan Jinzhao Chen +1 位作者 Xinchun Shen Jinglan Guo 《Open Journal of Applied Sciences》 2012年第4期116-119,共4页
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
关键词 QUATERNARY ammonium SURFACTANTS DSD acid Critical MICELLE concentration
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Structure, Growth and Characterization of Ammonium 5-Sulfosalicylic Acid Monohydrate Crystal 被引量:1
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作者 吕洋洋 叶李旺 +3 位作者 许智煌 曹有杰 苏根博 庄欣欣 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 2015年第3期453-460,共8页
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
关键词 ammonium 5-sulfosalicylic acid monohydrate crystal growth crystal structure fluorescence spectrum
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Ammonium Variational Trends and the Ammonia Neutralization Effect on Acid Rain over East Asia
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作者 GAO Chao WANG Zi-Fa Enagnon A. GBAGUIDI 《Atmospheric and Oceanic Science Letters》 2010年第2期120-126,共7页
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
关键词 acid rain ammonium neutralization effect
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单相缓速酸酸蚀裂缝导流规律
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作者 崔波 冯浦涌 +2 位作者 姚二冬 荣新明 周福建 《钻井液与完井液》 CAS 北大核心 2024年第2期270-278,共9页
低渗碳酸盐岩酸压成功的关键在于酸压后形成可在地层闭合压力下保持高导流能力的酸蚀裂缝。单相缓速酸是一种具有纳米结构、低伤害、低摩阻及高缓速性能的新型酸液体系,应用潜力大,但其酸蚀裂缝导流规律尚不明确。以光滑岩板和粗糙岩板... 低渗碳酸盐岩酸压成功的关键在于酸压后形成可在地层闭合压力下保持高导流能力的酸蚀裂缝。单相缓速酸是一种具有纳米结构、低伤害、低摩阻及高缓速性能的新型酸液体系,应用潜力大,但其酸蚀裂缝导流规律尚不明确。以光滑岩板和粗糙岩板为实验对象,以盐酸、胶凝酸和乳化酸为对比,利用酸液刻蚀和酸蚀裂缝导流实验、表面形貌扫描和连续强度测试仪,研究了酸液类型、交替注入级数、注入速度、黏度比、反应时间、岩板类型对导流能力的影响。结果表明:单相缓速酸相对于盐酸、胶凝酸和乳化酸,可形成强沟道型刻蚀形貌,差异化溶蚀程度高,岩板强度损伤减缓,在高闭合压力下可保持较高的导流能力。提高酸液交替注入级数(≥3级)、注入速度、黏度比(黏度差≥50 mPa·s)及岩板初始表面粗糙度,有助于形成优势酸液流通通道。单相缓速酸实现高导流酸蚀裂缝机理为:(1)黏性指进形成差异化刻蚀沟道;(2)主蚓孔滤失形态及“虹吸”效应减缓裂缝表面强度损伤。 展开更多
关键词 单相缓速酸 碳酸盐岩 酸蚀裂缝导流 差异化酸蚀 岩板强度损伤
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乙二胺四乙酸-乙酸铵盐交换法测定阳离子交换量方法优化
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作者 王卓 郭全恩 +1 位作者 曹诗瑜 展宗冰 《化学分析计量》 CAS 2024年第2期87-92,共6页
针对乙二胺四乙酸(EDTA)-乙酸铵交换法测定土壤阳离子交换量耗时长的问题,对方法的搅拌方式、搅拌时间、蒸馏时间进行优化。优化后分析条件为:用磁力搅拌器代替人工橡皮头玻璃棒搅拌,确定搅拌时间为90 s,确定蒸馏时间为6 min。选择4个... 针对乙二胺四乙酸(EDTA)-乙酸铵交换法测定土壤阳离子交换量耗时长的问题,对方法的搅拌方式、搅拌时间、蒸馏时间进行优化。优化后分析条件为:用磁力搅拌器代替人工橡皮头玻璃棒搅拌,确定搅拌时间为90 s,确定蒸馏时间为6 min。选择4个不同地区不同阳离子交换量的土壤标准物质用优化前、后的方法分别进行7次测定,其检测结果相对标准偏差为1.53%~5.32%;28个实际样品进行成对二样本均值分析,优化前、优化后测定的土壤阳离子交换量结果无显著性差异;对优化前、后28个土壤样品阳离子交换量测定结果进行相关性分析,线性相关显著,相关系数r=0.998。结果表明,EDTA-乙酸铵交换法优化前、后均具有较好的精密度和准确度,结果无显著性差异,EDTA乙酸铵交换法优化后的方法检测时间(1人测定8个样品)由280 min缩短到130 min,提高了检测效率,适合批量石灰性土壤阳离子代换量的测定。 展开更多
关键词 土壤 阳离子交换量 乙二胺四乙酸-乙酸铵交换法 磁力搅拌器
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Dawson型磷钨酸季铵盐对亚甲基蓝废水的光催化降解
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作者 刘雪梅 郭珂欣 +1 位作者 李金环 李慧敏 《水处理技术》 CAS CSCD 北大核心 2024年第2期90-93,共4页
采用共沉淀法制备了一种新的Dawson型磷钨酸十二烷基三甲基铵盐[C_(15)H_(34)N]_(6)P_(2)W_(18)O_(62)·2H_(2)O,通过红外光谱、热重分析、EDS能谱和扫描电镜对其组成、结构及形貌进行了表征,采用BET氮气吸附测定了比表面积。以亚... 采用共沉淀法制备了一种新的Dawson型磷钨酸十二烷基三甲基铵盐[C_(15)H_(34)N]_(6)P_(2)W_(18)O_(62)·2H_(2)O,通过红外光谱、热重分析、EDS能谱和扫描电镜对其组成、结构及形貌进行了表征,采用BET氮气吸附测定了比表面积。以亚甲基蓝为模拟染料废水,研究其光催化性能和降解亚甲基蓝的动力学行为,研究结果表明:14 mg/L的50 mL亚甲基蓝模拟染料废水在pH为4的条件下,加入20 mg催化剂,35 W紫外灯光照2 h,亚甲基蓝降解率达到95.0%,光催化降解反应符合一级动力学模型,动力学方程为:lnρ0/ρt=0.051 7t,降解速率常数为0.051 7 min-1,半衰期为13.4 min,表明Dawson型磷钨酸十二烷基三甲基铵对亚甲基蓝的降解具有高效的光催化活性,且重复使用催化性能好,循环5次后的降解率达到94.53%。 展开更多
关键词 Dawson结构磷钨酸 季铵盐 表征 光催化 亚甲基蓝
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草酸浓度调控对水系锌离子电池正极材料NH_(4)V_(4)O_(10)合成的优化
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作者 蔺何 刘晨帆 张禹 《新疆大学学报(自然科学版中英文)》 CAS 2024年第4期427-434,共8页
采用一步水热法,调整不同的草酸含量制备了NH_(4)V_(4)O_(10)(NVO)样品,并研究其作为水系锌离子电池正极材料的电化学性能.实验发现:草酸的浓度在决定样品组成上起到了关键性作用.当浓度较低时,得到NVO和(NH_(4))_(2)V_(4)O_(9)的混合相... 采用一步水热法,调整不同的草酸含量制备了NH_(4)V_(4)O_(10)(NVO)样品,并研究其作为水系锌离子电池正极材料的电化学性能.实验发现:草酸的浓度在决定样品组成上起到了关键性作用.当浓度较低时,得到NVO和(NH_(4))_(2)V_(4)O_(9)的混合相;草酸浓度过高则会导致VO_(2)的生成.当偏钒酸铵与草酸的摩尔比保持在1∶1时,成功合成了纯相NVO.电化学测试结果表明:纯相NVO在0.2 A·g^(-1)的电流密度下,比容量达到了479.3 mAh·g^(-1),性能显著优于其它样品.此外,该材料在0.1 mV·s^(-1)的扫描速率下,赝电容贡献率高达82.48%. 展开更多
关键词 锌离子电池 正极材料 草酸 偏钒酸铵
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施用不同品种氮肥对麦套花生生长和产量的影响 被引量:1
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作者 胡家钰 杨阳 +6 位作者 张红燕 高兵阳 王灵璐 闫军营 孙笑梅 赵亚南 叶优良 《中国农业科技导报》 CAS CSCD 北大核心 2024年第2期191-197,共7页
为研究砂质土壤上追施不同类型氮肥对麦套花生生长发育和产量的影响,在河南新乡市开展田间试验,分别设置不施肥(对照)、施用氯化铵、硫酸铵、硝酸铵钙、普通尿素、腐植酸尿素、控释尿素共7个处理,分析不同处理对花生株高、分枝数、复叶... 为研究砂质土壤上追施不同类型氮肥对麦套花生生长发育和产量的影响,在河南新乡市开展田间试验,分别设置不施肥(对照)、施用氯化铵、硫酸铵、硝酸铵钙、普通尿素、腐植酸尿素、控释尿素共7个处理,分析不同处理对花生株高、分枝数、复叶数、干物质和产量的影响。结果表明,与对照相比,施用不同类型氮肥均提高了花生的株高,其中尿素处理的株高在各个时期均较高;腐植酸尿素和控释尿素处理的株高在生育后期较高。施用氮肥能促进花生分枝,下针期以前以氯化铵、尿素和控释尿素处理的增幅较大。氮肥类型显著影响花生复叶数,其中硫酸铵和硝酸铵钙处理花生的复叶数在生育前期较少而后期较多;腐植酸尿素和控释尿素处理在前期较多但成熟期较少;氯化铵和尿素处理在整个生育期则较为平稳。施用各类型氮肥均显著提高了花生膨果期和成熟期的干物质量。与对照相比,追施不同类型氮肥可增产25.0%~61.0%,其中硝酸铵钙和腐植酸尿素增产幅度最大;尿素和控释尿素的增产效果高于硫酸铵和氯化铵;且施用硝酸铵钙、尿素和控释尿素处理花生的坏果率低于其他处理。综上所述,本研究条件下,麦套花生追施氮肥可促进花生生长并提高产量,其中硝酸铵钙的增产效果最佳;腐植酸尿素和控释尿素也具有较好效果。 展开更多
关键词 花生 套作 氮肥种类 硝酸铵钙 腐植酸 控释肥
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Solubility of hemimorphite in ammonium sulfate solution at 25 °C 被引量:1
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作者 李琴香 胡慧萍 +1 位作者 曾德文 陈启元 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2013年第7期2160-2165,共6页
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
关键词 HEMIMORPHITE ammonium sulfate silicic acid SOLUBILITY
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斜生栅藻对全氟辛酸和Zn^(2+)联合胁迫的生理生化响应
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作者 杨顺航 李立杰 +8 位作者 余佳妮 葛恒 马永华 廖木兰 尤德雨 李慧明 谭凤霞 柴毅 汪正刚 《广东海洋大学学报》 CAS CSCD 北大核心 2024年第1期64-75,共12页
【目的】探究全氟辛酸(PFOA)与重金属锌(Zn^(2+))单一及联合暴露对斜生栅藻(Scenedesmus obliquus)的急性毒性效应和作用机制,为全氟化合物(Perfluorinated compounds,PFCs)和重金属在水生生态系统中的联合风险评估提供理论基础。【方... 【目的】探究全氟辛酸(PFOA)与重金属锌(Zn^(2+))单一及联合暴露对斜生栅藻(Scenedesmus obliquus)的急性毒性效应和作用机制,为全氟化合物(Perfluorinated compounds,PFCs)和重金属在水生生态系统中的联合风险评估提供理论基础。【方法】将1×10^(6)mL^(-1)斜生栅藻分别在0~16 mg/L Zn^(2+)、0~350 mg/L PFOA单一处理组及0~1.5 TU联合处理组暴露96 h,分析暴露条件对斜生栅藻的细胞浓度、藻细胞叶绿素a(Chl a)、总蛋白(TP)含量、抗氧化系统、细胞外部形态、转化氨氮能力、Zn^(2+)与PFOA去除率等指标的影响。【结果与结论】处理96 h,Zn^(2+)与PFOA单一胁迫抑制斜生栅藻生长的半最大效应质量浓度(96 h-EC_(50))分别为14.17 mg/L和198.98 mg/L;二者联合胁迫96 h-EC_(50)为0.97 TU,作用模式为部分相加作用。Zn^(2+)和PFOA单一及联合胁迫下,藻细胞Chl a含量和TP含量均显著下降(P<0.05),表明藻细胞光合作用受阻;活性氧(ROS)活性和丙二醛(MDA)含量显著上升(P<0.05),促使细胞膜通透性增强,线粒体膜电位降低;T-AOC和SOD活性也因ROS的过度积累而呈现升高趋势。扫描电镜结果表明,联合胁迫会破坏藻细胞的外部形态。暴露液中总氮和氨氮含量都随污染物暴露浓度的增加而增加,联合暴露组与对照组相比差异更为明显;硝态氮含量始终保持低水平。斜生栅藻对PFOA的去除率仅有2%,对Zn^(2+)去除率为37.5%且随暴露浓度的增加而逐渐降低,表明斜生栅藻可以有效去除锌污染,但对全氟辛酸污染去除效果欠佳。 展开更多
关键词 斜生栅藻 重金属锌 全氟辛酸 暴露 急性毒性效应 转化氨氮 去除
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共掺杂TB_(0.5)Zr_(0.5)H_(0.5)PW催化合成苯甲醛乙二醇缩醛
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作者 陈梓怡 郑芷洁 +3 位作者 叶伟健 周凡 杨水芬 韩晓祥 《精细化工》 EI CAS CSCD 北大核心 2024年第6期1292-1301,共10页
通过离子交换法制备了一系列季铵盐(苄基三乙基氯化铵、四丁基溴化铵和十六烷基三甲基溴化铵)和锆盐(ZrCl4)共掺杂磷钨酸催化剂。利用SEM、FTIR、XRD、XPS、TGA-DTG及正丁胺电位滴定法对催化剂进行了表征,并对其催化乙二醇与苯甲醛的缩... 通过离子交换法制备了一系列季铵盐(苄基三乙基氯化铵、四丁基溴化铵和十六烷基三甲基溴化铵)和锆盐(ZrCl4)共掺杂磷钨酸催化剂。利用SEM、FTIR、XRD、XPS、TGA-DTG及正丁胺电位滴定法对催化剂进行了表征,并对其催化乙二醇与苯甲醛的缩醛反应性能进行了考察。采用单因素和响应面实验考察了催化剂用量(以苯甲醛质量为基准,下同)、n(乙二醇)∶n(苯甲醛)、带水剂(环己烷)用量和反应时间对苯甲醛乙二醇缩醛(BEGA)产率的影响,并考察了催化剂的重复使用性能。结果表明,四丁基溴化铵(TB)和ZrCl4共掺杂的磷钨酸催化剂TB_(0.5)Zr_(0.5)H_(0.5)PW具有最优异的催化性能,催化剂强的Brønsted与Lewis酸中心间的协同效应及“假液相”特性是其具有高活性的原因;以TB_(0.5)Zr_(0.5)H_(0.5)PW为催化剂,经响应面优化制备BEGA最佳工艺条件为n(乙二醇)∶n(苯甲醛)=1.5∶1、催化剂用量为1.9%、反应温度110℃、反应时间3 h、带水剂用量12.6 mL,在该条件下BEGA产率为94.6%;TB_(0.5)Zr_(0.5)H_(0.5)PW使用6次后,BEGA产率为91.9%。 展开更多
关键词 磷钨酸 季铵盐 缩醛反应 苯甲醛乙二醇缩醛 催化技术
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低浓度氨暴露对入侵性物种红耳滑龟幼体肝脏、脑、肾脏代谢产物的影响
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作者 莫冬梅 李涵 +2 位作者 王婉铃 孟沁园 陆洪良 《杭州师范大学学报(自然科学版)》 CAS 2024年第1期58-62,98,共6页
水体中过量氨会对水生生物造成不利影响,但氨胁迫对龟类动物毒害作用的研究却非常少.将红耳滑龟幼体暴露于一定质量浓度(0.3和3.0 mg/L)的氯化铵溶液中30 d,通过测定肝脏、脑和肾脏中的代谢产物来评估氨胁迫下该物种不同组织的代谢反应... 水体中过量氨会对水生生物造成不利影响,但氨胁迫对龟类动物毒害作用的研究却非常少.将红耳滑龟幼体暴露于一定质量浓度(0.3和3.0 mg/L)的氯化铵溶液中30 d,通过测定肝脏、脑和肾脏中的代谢产物来评估氨胁迫下该物种不同组织的代谢反应.结果显示氨胁迫导致这些组织中一系列代谢物的改变,主要涉及氨基酸分解和合成代谢、能量代谢以及神经信息传递等途径的干扰.即使在较低水平氨胁迫下,红耳滑龟不同组织内的一些代谢途径可能会发生变化,从而影响其个体的健康状态. 展开更多
关键词 红耳滑龟 氨暴露 组织代谢产物 氨基酸代谢 神经递质
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Development of a radiomics model to discriminate ammonium urate stones from uric acid stones in vivo:A remedy for the diagnostic pitfall of dual-energy computed tomography
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作者 Junjiong Zheng Jie Zhang +9 位作者 Jinhua Cai Yuhui Yao Sihong Lu Zhuo Wu Zhaoxi Cai Aierken Tuerxun Jesur Batur Jian Huang Jianqiu Kong Tianxin Lin 《Chinese Medical Journal》 SCIE CAS CSCD 2024年第9期1095-1104,共10页
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
关键词 ammonium urate Dual-energy scanned projection radiography Radiomics Uric acid UROLITHIASIS
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烟秆炭与尿素配施对酸性红壤理化特征与作物生长的影响
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作者 何翰宇 周瑞春 +3 位作者 王豪吉 程圆钦 官会林 徐武美 《云南师范大学学报(自然科学版)》 2024年第3期54-59,共6页
为研究生物炭与氮素配施对作物生长的影响,向酸性红壤中添加2%的烟秆炭,尿素添加量为20、40 mg·kg^(-1)与60 mg·kg^(-1)(以氮素计,标记为T1、T2和T3),以不施用尿素为对照(CK),以广泛食用的青菜(Brassica rapa var.chinensis)... 为研究生物炭与氮素配施对作物生长的影响,向酸性红壤中添加2%的烟秆炭,尿素添加量为20、40 mg·kg^(-1)与60 mg·kg^(-1)(以氮素计,标记为T1、T2和T3),以不施用尿素为对照(CK),以广泛食用的青菜(Brassica rapa var.chinensis)为试验作物,种植80 d后采收,并采集土样用于理化性质与脲酶活性分析.结果表明,青菜产量随施氮量的升高而显著增加(P<0.05),T1、T2和T3处理下青菜产量较CK分别增加了53%、75%与103%.随着尿素施加量的增加,土壤速效氮含量与电导率显著升高,而pH降低(P<0.05).多元回归分析表明,土壤速效氮含量是影响青菜产量的关键因素(R^(2)=51.1%),且随着尿素添加量的增加,青菜叶片中氮含量升高(P<0.05),表明作物氮素营养得到了有效改善.因此,向施炭的酸性红壤中添加速效氮,是促进作物生长与产量提升的有效措施. 展开更多
关键词 烟秆炭 铵态氮 硝态氮 作物产量 酸性红壤
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污泥4种热处理产物中磷的化学提取-沉淀回收性能
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作者 张芷晗 罗欣宜 +3 位作者 张艾嘉 杨应举 刘晶 乔瑜 《洁净煤技术》 CAS CSCD 北大核心 2024年第3期52-58,共7页
污水处理厂污泥中磷含量较高,对磷进行回收能有效实现磷资源的二次利用。采用磷酸铵镁(MAP)回收法分别对污泥4种热处理产物阴燃灰、掺烧灰、焚烧灰和热解焦的酸浸出液进行磷回收试验,重点分析了各热处理产物在酸浸出-MAP路线下的磷回收... 污水处理厂污泥中磷含量较高,对磷进行回收能有效实现磷资源的二次利用。采用磷酸铵镁(MAP)回收法分别对污泥4种热处理产物阴燃灰、掺烧灰、焚烧灰和热解焦的酸浸出液进行磷回收试验,重点分析了各热处理产物在酸浸出-MAP路线下的磷回收性能,包括磷沉淀率、产物中磷和杂质含量,并进一步探究了沉淀产物的环境安全性。结果表明,通过酸浸出-MAP回收法,单位质量沉淀产物磷质量分数达19.82~31.71 mg/g,原污泥中磷回收率达49.25%~65.81%。磷回收性能由高到低依次为焚烧灰、热解焦、阴燃灰、掺烧灰。酸浸出-MAP回收产物中含有大量Ca、Fe、Al和Si杂质,且含有一定量Zn、Pb、Cr、Cu、Cd、As和Ni,其中Zn含量远高于其他重金属含量。产物纯度和环境安全性由高到低依次为焚烧灰、掺烧灰、热解焦、阴燃灰。在沉淀产物的环境安全性方面,阴燃灰、焚烧灰和热解焦的酸浸出-MAP回收产物中重金属含量均符合GB/T 23349—2009《肥料中砷、镉、铅、汞生态指标》和GB 4284—2018《农用污泥污染物控制标准》。掺烧灰的酸浸出-MAP回收产物中Cd质量分数为3.20 mg/kg,超过农用污泥污染物控制标准限值3.00 mg/kg。 展开更多
关键词 污泥 热处理 磷回收 酸浸出-磷酸铵镁回收法 磷沉淀率 杂质含量
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