UV-B增加对菠菜生长发育和品质的影响

研究了在大田栽培和自然光的条件下，模拟紫外辐射的增加对菠菜生长发育和品质的影响。生长指标的分析结果表明，随着UV-B辐射的增加，菠菜的干质量、叶面积、绿叶数、株高生长均呈降低趋势，而且随着UV-B越强，降低程度越大，并在一定程度上延缓植株生长。品质指标的分析结果表明，UV-B辐射增强，菠菜叶片的可溶性糖质量分数降低，维生素C质量分数降低，随UV-B辐射强度增大，可溶性糖和维生素C质量分数降低的幅度愈大；UV-B辐射增强，菠菜叶片的蛋白质和抗坏血酸表现为质量分数升高，但当UV-B辐射超过一定强度，二者又表现为低于对照。     

新型地下水及设施的污染控制技术

利用核辐射法治理生物堵塞地下水井,在众多有希望的辐射净水技术中被证明是成功的和具有明显经济效益的工艺方法。描述了此项技术在德国、捷克、美国和俄国的应用和获得的经验．利用核辐射水力屏障法成功地就地净化了被氰化物污染的地下水,使出水中的氰化物浓度降低了一数量级。     

UV-B增加对麦田杂草看麦娘的影响

在大田群体条件下，研究了UV-B增加对麦田杂草发生、生长和种子产量的影响。结果表明：UV-B强度增加，看麦娘的密度显著增加；在小麦生育前期，看麦娘的单株茎蘖数下降，而在中后期显著增加；UV-B增加对小麦中后期看麦娘的生长有一定的促进效应；看麦娘叶片的叶绿素和类黄酮含量均表现为增加的趋势。在未来紫外线增加的条件下，看麦娘对小麦生产的影响可能会不断增加。     

The adsorption behavior of metals in aqueous solution by microplastics effected by UV radiation

Microplastics are considered as the carrier to heavy metals in the environment. But the sorption ability of microplastics influenced by photo-aging is remaining unclear. In the present study, the sorption of two kinds of metal ions (Cu²⁺ and Zn²⁺) in the aqueous solution by both the virgin and aged microplastics was investigated. Polyethylene terephthalate (PET) debris, one of the typical kinds of microplastics was chosen in this study. Photo-aging of microplastics in environment was simulated using UV radiation in the laboratory. Date analysis indicated that the aged microplastics had higher adsorption capacity of heavy metals than original ones. This could be related to the increased surface area and oxygen containing function appeared in the surface of aged microplastics after UV radiation. When prolonging the time of radiation, the enhanced adsorption capacities of microplastics appeared for Cu²⁺ and Zn²⁺. These results showed a great interaction between the aging degree of plastics and sorption capacity to heavy metals. Meanwhile, external conditions including temperature and pH value were also showed great influence to the adsorption behavior.     

干旱区黑碳沉降积雪反照率及雪粒径模拟研究

在以往研究基础上,利用单点实测数据驱动雪、冰及气溶胶辐射（SNICAR）区域物理模型,将微观数据与遥感的宏观技术相结合对积雪反照率与雪粒径进行数值模拟及反演.研究表明：积雪反照率会随着太阳天顶角的增大而增加,且在近红外波段的影响更加明显;在不同雪粒径、黑炭浓度下,积雪反照率都随着雪粒径、黑炭浓度的增大而减小,且颗粒越小的雪粒,粒径的减小对反照率的影响更为明显,而黑炭主要是对可见光波段有显著作用;利用SNICAR模型与MODIS数据反演北疆地区雪粒径,其精度可达0.749,实现了单点雪粒径向面状雪粒径的尺度转换.本研究揭示了干旱区季节性积雪中,气溶胶粒子存在情况下的积雪反照率连续变化特征,有效提高了积雪中雪粒径的反演精度,为积雪中气溶胶粒子对气候产生的辐射胁迫模拟提供了技术支持.     

过硫酸盐协同光催化纳米ZnO降解盐酸四环素的影响机制

以水葫芦为原料,制备了负载纳米ZnO的生物炭材料（ZnO-BC）,研究了单独光催化ZnO-BC和过硫酸钠（PS）协同ZnO-BC/UV体系氧化降解盐酸四环素（TC）.结果表明,PS协同ZnO-BC /UV体系的降解反应速率比单独光催化ZnO-BC时有显著提高,120min后降解率达到89.48%.PS可作为强氧化剂,利用纳米ZnO的光生电子产生SO₄^-·和·OH协同光催化反应.TC的反应过程可分为两个阶段：暗吸附阶段和光催化反应阶段.影响因素和响应面试验结果得出的影响顺序为PS浓度 > 紫外灯功率 > 初始pH值 > 纳米ZnO质量浓度.猝灭试验表明,在TC的降解中,SO₄^-·和·OH是参与反应的主要自由基.起氧化作用的自由基一部分在溶液中产生,另一部分由生物炭材料表面含氧官能团的作用和紫外光激发纳米ZnO产生.在此基础上,探讨了在TC降解过程中,PS与ZnO-BC的协同机理和协同作用的规律.     

UV强化草酸络合Fe3+活化过硫酸盐氧化降解苯胺

采用UV-草酸络合Fe~(3+)[UV-Fe(C_2O_4)3-3]活化过硫酸钠(PS)氧化降解苯胺,研究了Fe(C_2O_4)3-3浓度,PS浓度,pH对PS活化效率及苯胺氧化降解效果的影响机制.结果表明,Fe(C_2O_4)3-3浓度和pH决定了UV-Fe(C_2O_4)3-3体系中Fe~(3+)向Fe2+的转化过程,并对活化PS氧化降解苯胺产生显著影响.随着Fe(C_2O_4)3-3浓度增加,PS的分解率不断提高,但当浓度高于0.75 mmol·L~(-1)时,草酸根离子(C2O_2-4)对硫酸根自由基(SO·-4)的竞争以及SO·-4之间的相互淬灭作用降低了苯胺的降解效果,降解速率大小顺序为5 mmol·L~(-1)0.25 mmol·L~(-1)0.5 mmol·L~(-1)1 mmol·L~(-1)0.75 mmol·L~(-1);中性和碱性条件不利于Fe(C_2O_4)3-3发生光化学反应生成Fe2+,但当初始pH为7和9时,由于PS活化分解过程降低反应体系pH,反应300min时PS的活化率可分别达到74%和67%,苯胺去除率分别高达91%和97%,均高于初始pH为酸性条件下的结果;苯胺降解率随初始PS浓度增加而增大,当PS浓度大于10 mmol·L~(-1)时,苯胺降解过程由二级反应变为准一级反应,但此时过量的PS因与SO·-4发生反应而显著降低PS用于氧化降解苯胺的利用率.     

Using X-ray computed tomography and micro-Raman spectrometry to measure individual particle surface area, volume, and morphology towards investigating atmospheric heterogeneous reactions

Heterogeneous reactions on the aerosol particle surface in the atmosphere play important roles in air pollution, climate change, and global biogeochemical cycles. However, the reported uptake coefficients of heterogeneous reactions usually have large variations and may not be relevant to real atmospheric conditions. One of the major reasons for this is the use of bulk samples in laboratory experiments, while particles in the atmosphere are suspended individually. A number of technologies have been developed recently to study heterogeneous reactions on the surfaces of individual particles. Precise measurements on the reactive surface area, volume, and morphology of individual particles are necessary for calculating the uptake coefficient, quantifying reactants and products, and understanding the reaction mechanism better. In this study, for the first time we used synchrotron radiation X-ray computed tomography(XCT) and micro-Raman spectrometry to measure individual CaCO_3 particle morphology, with sizes ranging from 3.5–6.5 μm. Particle surface area and volume were calculated using a reconstruction method based on software threedimensional(3-D) rendering. The XCT was first validated with high-resolution fieldemission scanning electron microscopy(FE-SEM) to acquire accurate CaCO_3 particle surface area and volume estimates. Our results showed an average difference of only 6.1% in surface area and 3.2% in volume measured either by micro-Raman spectrometry or X-ray tomography. X-ray tomography and FE-SEM can provide more morphological details of individual Ca CO3 particles than micro-Raman spectrometry. This study demonstrated that X-ray computed tomography and micro-Raman spectrometry can precisely measure the surface area, volume, and morphology of an individual particle.     

Thermal analysis of tilted wick solar distillation-cum-drying system

The performance of the designed tilted wick solar water distillation-cum-drying unit has been tested at water flow rates of 50 and 65 ml/min in the distillation unit. Effect of water flow rates on the heat transfer coefficients of distillation and drying unit for drying ginger has been evaluated. The energy and exergy efficiency of the distillation system have also been evaluated. Average distillates of 2.36 and 2.2 l/m² were collected from the tilted wick solar still at flow rates of 50 and 65 ml/min, respectively. Large variation in convective and evaporative heat transfer coefficients of distillation unit has been observed at given water flow rates. Water flow rate in the distillation unit significantly affects the performance of the drying unit. Average convective heat transfer coefficients of 6.56 and 3.75 W/m^{2 o}C have been observed for drying ginger at flow rates of 50 and 65 ml/min, respectively. Energy and exergy efficiency of the distillation unit have been found to be nearly 19% and 0.9%, respectively. Experimental uncertainty has also been evaluated for distillation and drying units. The distillate cost for the developed distillation-cum-drying unit is calculated as $0.03729/l along with dried ginger of about 2.5 kg/m²/day.     

Thermal energy storage and thermodynamic properties of (E)-3-m-tolylbut-2-enoic acid as a medium temperature phase change material

Phase change materials (PCMs) that can store and release heat energy over the temperature range from 363 to 393 K are crucial for solar absorption cooling, and it is worthy to seek new solid-liquid PCMs candidates that melt and crystallize in this temperature range. In this paper, (E)-3-m-tolylbut-2-enoic acid (mTBEA) was applied as a PCM candidate. Its thermal energy storage properties and thermal stability were systematically investigated. The results showed that mTBEA melted at 382.9 ± 0.5 K and crystallized at about 364 K, with a melting enthalpy (Δ_fusH) of 138.4 ± 6.9 J g^?1 and showed good long-term cyclic stability and thermal stability. The supercooling of mTBEA was stabilized at about 20 K, indicating that the conservation condition of melted mTBEA could be simple. In addition, the melted mTBEA could release all the absorbed thermal energy upon crystallizing. Besides, mTBEA exhibited good thermal stability for it to be applied as PCM. Hence, mTBEA is a promising PCM candidate for solar absorption cooling. Furthermore, the heat capacity of mTBEA was measured by modulated temperature differential scanning calorimetry (MTDSC) over the temperature range from 198.15 to 431.15 K, and the molar thermodynamic functions, [H_T-H_298.15]_m and [S_T-S_298.15]_m, were calculated based on the fitted molar heat capacity data.