气溶胶辐射效应对气象和环境影响的观测与模拟研究

选取2015年和2019年不同代表年份,结合外场观测和数值模拟,分析了天津地区不同季节不同天气(晴天、多云、霾)下,气溶胶辐射效应对整层大气透过率和地表入射太阳辐射的影响,以及这种影响在不同年份的差异.借助WRF-Chem模式模拟分析了重污染期间气溶胶辐射效应对垂直方向上气象要素廓线、边界层结构以及PM_2.5浓度的反馈机制.结果表明:霾污染可导致大气透过率明显下降,春、秋、冬不同季节,霾污染导致中午大气透过率分别下降0.09,0.11和0.09.全年平均霾污染可导致大气透过率降低约15.5%.云量的增多也可导致大气透过率明显下降,多云天气下大气透过率相比晴天减小约22.4%.霾和云对大气透过率的影响还与太阳高度角有关,当太阳高度角>60°时,霾污染导致大气透过率下降8.6%.随污染等级提高,气溶胶对太阳辐射的衰减作用也越强,天津地区空气质量分别为Ⅰ～Ⅰ级时,中午地表入射短波辐射呈稳定下降趋势,依次为484,446,439,342,328和253W/m².重污染期间,气溶胶辐射效应导致大气低层(250m以下)降温(0.8℃)增湿(3.8%...     

黄土高原不同植被带人工刺槐林土壤团聚体稳定性及其化学计量特征

为研究黄土高原不同植被带对土壤团聚体稳定性及团聚体化学计量变化特征的影响,本研究选取黄土高原不同植被带人工刺槐林地土壤为研究对象,分析了不同粒径团聚体含量,团聚体化学计量及稳定性指标.结果表明, 2 mm和0. 25～2 mm粒径团聚体含量,机械团聚体的平均重量直径(E_(MWD))和机械团聚体的几何平均直径(E_(GMD))表现为森林带森林草原带草原带,而0. 053～0. 25 mm粒径团聚体含量和可蚀性因子K呈现相反的变化特点;各粒径团聚体有机碳和全氮含量在3个植被带整体表现为森林带显著高于森林草原带和草原带,而全磷含量在各植被带间无明显变化规律;有机碳和全氮含量在草原带以0. 053 mm和0. 25～2 mm粒径占绝对优势,在森林草原带以0. 053～0. 25 mm和0. 25～2 mm粒径为主,而森林带各粒径间均无显著差异;草原带和森林草原带0. 053 mm粒径全磷含量最高,而森林带全磷含量在各粒径间无显著差异;0. 053 mm和0. 053～0. 25 mm粒径团聚体C∶N值以草原带和森林草原带高于森林带,而0. 25～2 mm和 2 mm粒径在3个植被带间无显著差异;各粒径C∶P和N∶P值以森林带显著高于森林草原带和草原带.综上可见,土壤团聚体稳定性和团聚体化学计量在3个植被带间存在较大差异,团聚体稳定性和团聚体有机碳、全氮含量整体表现为森林带显著高于森林草原带和草原带.     

我国林地土壤有效态镉的影响因素及拟合模型

选取全国13个具有代表性的不同气候带和植被类型的森林土壤,通过外源添加重金属镉（Cd）,比较分析土壤Cd的固-液分配系数（K_d）和有效态Cd的分布特征,探讨了土壤/土壤溶液性质对K_d及土壤有效态Cd的影响,并建立了土壤K_d及有效态Cd的拟合模型.结果表明,在不同浓度Cd处理的土壤中,其K_d值的变化范围为0.91~623.66L/kg,平均值为53.11L/kg,最大值和最小值的差异达到684.37倍;土壤孔隙水中Cd浓度（PW-Cd）的变化范围为0.309~104.450mg/L,其最大值与最小值的差异为338;DTPA提取态Cd含量（DTPA-Cd）从未添加Cd处理的本底土壤C0至最大添加量128mg/kg,其最大值与最小值的差异分别为9和1.4倍.土壤溶液pH值与lgK_d呈显著正相关（R²=0.49,P<0.001）,其与PW-Cd含量呈显著负相关（R²=0.41,P<0.05）;单一的土壤溶液Mg²⁺可解释46%的DTPA-Cd的变异.在对土壤性质的回归分析中,并未发现有单一的主控土壤性质影响Cd的固液分配,当回归方程中加入其它土壤或溶液性质时,可在一定程度上提高拟合模型的预测能力.总之,土壤溶液pH值和Mg²⁺对K_d和有效态Cd含量的影响比较显著.     

Application of FeIII-TAML/H2O2 system for treatment of fluoroquinolone antibiotics

Over the recent past, fluoroquinolone antibiotics (FQs) have raised extensive attention due to their potential to induce the formation of resistance genes and “superbugs”, thus various advanced oxidation techniques have been developed to eliminate their release into the environment. In the present study, the prototype tetraamido macrocyclic ligand (Fe^III-TAML)/hydrogen peroxide (H₂O₂) system is employed to degrade FQs (i.e., norfloxacin and ciprofloxacin) over a wide pH range (i.e., pH 6-10), and the reaction rate increases with the increase in pH level. The effect of dosage of Fe^III-TAML and H₂O₂ on the degradation of FQs is evaluated, and the reaction rate is linearly correlated with the added amount of chemicals. Moreover, the impact of natural organic matters (NOM) on the removal of FQs is investigated, and the degradation kinetics show that both NOM type and experimental concentration exhibit negligible influence on the oxidative degradation of selected antibiotics. Based on the results of liquid chromatography-high resolution mass spectrometry and theoretical calculations, the reaction sites and pathways of FQs by Fe^III-TAML/H₂O₂ system are further predicted and elucidated.     

Ag3PO4/g-C3N4复合光催化剂的制备及其可见光催化性能

采用简单的原位沉淀法合成了可见光驱动型光催化剂Ag₃PO₄/g-C₃N₄.利用X-射线衍射（XRD）、傅里叶红外光谱（FT-IR）、扫描电子显微镜（SEM）、X-射线能谱（XPS）以及紫外可见漫反射光谱（UV-Vis DRS）等表征手段对合成的样品进行了表征.与单一的Ag₃PO₄和g-C₃N₄相比,Ag₃PO₄/g-C₃N₄复合材料对左氧氟沙星表现出了更高的催化效率.根据能带分析和自由基捕获试验,提出了Ag₃PO₄/g-C₃N₄复合材料Z型异质结构的作用机制.     

优化施肥模式对我国热带地区水稻-豇豆轮作系统N2O和CH4排放的影响

选择海南典型的水稻-豇豆轮作系统进行氧化亚氮(N_2O)和甲烷(CH_4)排放的原位监测,探究不同施肥模式下该系统土壤温室气体排放特征.试验设当地常规施肥对照(CON)、优化施肥量(OPT)、有机无机配施(ORG)、缓控肥替代优化(SCOPT)及不施氮对照(CK)共5个处理,采用静态箱-气相色谱法监测整个种植季土壤N_2O和CH_4排放,并估算增温潜势(GWP)和温室气体排放强度(GHGI).结果表明,各处理水稻季N_2O累积排放量为0. 19～1. 37 kg·hm~(-2),相较于CON处理,优化施肥处理N_2O减排50%～86%;豇豆季N_2O累积排放量为1. 29～3. 55 kg·hm~(-2),除ORG增加14%,其他处理减排16%～59%.各处理水稻季CH_4累积排放量为4. 67～14. 23 kg·hm~(-2),CK、OPT和ORG处理分别较CON增加116%、22%和102%,而SCOPT减少了29%;豇豆季CH_4累积排放量为0. 03～0. 26 kg·hm~(-2),期间出现CH_4吸收.比较两个作物季和休闲期对农田土壤直接排放的温室气体GWP的贡献率,豇豆季在CH_4排放极低的情况下,仍有44. 7%～54. 5%的占比;两种温室气体比较中,N_2O对GWP的贡献率为66. 7%～77. 2%. SCOPT处理的GWP和两季作物GHGI均显著低于CON处理.3个优化施肥处理中,SCOPT的增产减排效果最显著,为最优的施肥方案.     

Antibiotic resistance genes in manure-amended paddy soils across eastern China: Occurrence and influencing factors

• Manure fertilization resulted in antibiotic residues and increased metal contents. • The tet and sul genes were significantly enhanced with manure fertilization. • Soil physicochemical properties contributed to 12% of the variations in ARGs. • Soil metals and antibiotics co-select for ARGs. Pig manure, rich in antibiotics and metals, is widely applied in paddy fields as a soil conditioner, triggering the proliferation of antibiotic resistance genes (ARGs) in soil. However, comprehensive studies on the effects of manure fertilization on the abundance of ARGs and their influencing factors are still insufficient. Here, pig manure and manure-amended and inorganic-amended soils were collected from 11 rice-cropping regions in eastern China, and the accumulation of antibiotics, metals, and ARGs was assessed simultaneously. The results showed that manure fertilization led to antibiotic residues and increased the metal content (i.e., Zn, Cu, Ni, and Cr). Tetracycline and sulfonamide resistance genes (tetM, tetO, sul1, and sul2) were also significantly enhanced with manure fertilization. According to variance partitioning analysis, the most important factors that individually influenced ARGs were soil physicochemical properties, accounting for 12% of the variation. Significant correlations between soil nutrients and ARGs indicated that manure application enhanced the growth of resistant microorganisms by supplying more nutrients. Metals and antibiotics contributed 9% and 5% to the variations in ARGs, respectively. Their co-occurrence also increased the enrichment of ARGs, as their interactions accounted for 2% of the variation in ARGs. Interestingly, Cu was significantly related to most ARGs in the soil (r = 0.26–0.52, p<0.05). Sulfapyridine was significantly related to sul2, and tetracycline resistance genes were positively related to doxycycline. This study highlighted the risks of antibiotic and ARG accumulation with manure fertilization and shed light on the essential influencing factors of ARGs in paddy soils.     

小型四旋翼无人机悬停状态气动干扰与安全间隔研究*

为保证小型旋翼无人机近距编队悬停状态的安全性,采用数值模拟方法研究不同横向和纵向间隔双机悬停流场特征和气动参数变化规律,通过与实验结果对比,验证数值仿真方法的准确性。研究结果表明:无人机内部旋翼间的气动干扰会导致整机单旋翼拉力降低、扭矩增大,使整机气动效率下降;当双机无横向间隔时,双机下洗流场保持对称,同时2股下洗流叠加,呈现较明显的横向扩张趋势,此时后机所受气动影响主要为拉力损失,当纵向间隔大于5 D时,该影响基本消失;当横向间隔X=1 D时,位于尾流区一侧的旋翼拉力减小,后机所受俯仰力矩作用显著,无人机有侧翻风险;横向间隔X≥2 D时,2机之间气动干扰较弱,为较安全区域。     

极端温度下帐篷内部热环境适应性实验及模拟研究*

为揭示民用救灾帐篷热环境适应性变化规律,通过大尺度环境气候舱构建高温与低温环境,采用Ansys Fluent商用软件代码进行仿真验证,并对帐篷蓬围结构和内部热环境分布变化规律进行实验与数值模拟。研究结果表明:使用大尺度环境舱直接进行模拟帐篷内外热环境变化可行,其内部热环境变化规律与实验基本一致;帐篷特殊的篷围结构导致高温环境下帐篷内部温度高于外界,帐内人员头部和脚部温差可达5 ℃,低温环境下帐篷同一高度横向区域温度对称分布,在中心区域温度较低,边缘和中心温差近8 ℃。     

内电解-Fenton 氧化-膜生物反应器处理腈纶废水

采用内电解-Fenton 氧化-序批式膜生物反应器组合工艺处理腈纶废水.结果表明,在进水Ph 值为3、内电解反应时间2h、H₂O₂ 浓度1500 mg/L、Fe²⁺浓度600mg/L、Fenton 反应时间2h 的条件下,内电解-Fenton 组合工艺对COD 的去除率为72%,进水COD 从1328mg/L下降到369mg/L,废水BOD₅/COD 从0.14 上升到0.33,CN-从8.6mg/L 下降到0.215mg/L,提高了废水可生化性,为后续的生物处理创造了良好的条件.出水采用序批式膜生物反应器处理,在停留时间20h、缺氧搅拌90min、好氧120min 条件下,COD 去除率为80%,NH₄₊-N 去除率95%,BOD₅ 去除率92.6%,CN-去除率90.7%.最终出水COD、BOD5、NH4+-N、CN-、SS 分别为61,9.3,2.55,0.02,13mg/L