亚硝态氮胁迫下菲律宾蛤仔实时定量P CR内参基因的筛选

为了更好地从基因角度研究亚硝态氮对贝类的生态毒性,需要筛选一个合适的内参基因作为参考,对其毒性相关基因进行定量表达分析。本研究以菲律宾蛤仔(Ruditapes philippinarum)作为研究对象,以亚硝态氮胁迫的鳃组织cDNA作为模板,利用geNorm软件和NormFinder软件对6个候选内参基因进行表达稳定性分析,并对2个结果做了综合赋权分析。结果显示,geNorm分析的基因表达稳定性结果为ActinCyPAEF1αUbi18STubu,NormFinder软件分析的结果为ActinUbiCyPAEF1α18STubu,最后经加权赋值法综合分析获得6个候选基因的表达稳定性为ActinCyPAUbiEF1α18STubu,即Actin为表达最稳定的基因。因此,Actin可以作为衡量亚硝态氮胁迫后菲律宾蛤仔鳃组织中基因表达的内参基因。     

深圳大气有机硝酸酯粒径分布特征和来源研究

于2021年3月30日至2021年4月17日利用超高分辨率气溶胶飞行时间质谱(Long-ToF-AMS),对深圳城市大气中的颗粒态有机硝酸酯(pON)开展高精度分析.基于两种估算pON的方法,计算得出pON对有机气溶胶(OA)的贡献占比为5.08％～11.00％.pON的日变化特征显示,其高值主要出现在夜间时段(19:...     

A novel sequence batch membrane carbonation photobioreactor developed for microalgae cultivation

A novel SBM-C-PBR was constructed for microalgae cultivation. Membrane fouling was greatly mitigated by membrane carbonation. NH₄⁺ and P removal rates were around 80% in SBM-C-PBR. Biomass was completely retained by membrane. In this study, a novel sequence batch membrane carbonation photobioreactor was developed for microalgae cultivation. Herein, membrane module was endowed functions as microalgae retention and CO₂ carbonation. The results in the batch experiments expressed that the relatively optimal pore size of membranes was 30 nm, photosynthetically active radiation was 36 W/m² and the CO₂ concentration was 10% (v/v). In long-term cultivation, the microalgal concentration separately accumulated up to 1179.0 mg/L and 1296.4 mg/L in two periods. The concentrations of chlorophyll a, chlorophyll b and carotenoids were increased about 23.2, 14.9 and 6.3 mg/L respectively in period I; meanwhile, the accumulation was about 25.0, 14.5, 6.6 mg/L respectively in the period II. Furthermore, the pH was kept about 5.5–7.5 due to intermittent carbonation mode, which was suitable for the growth of microalgae. Transmembrane pressure (TMP) was only increased by 0.19 and 0.16 bar in the end of periods I and II, respectively. The pure flux recovered to 75%–80% of the original value by only hydraulic cleaning. Scanning electron microscope images also illustrated that carbonation through membrane module could mitigate fouling levels greatly.     

钢板组合PEC柱-削弱截面钢梁组合框架抗震试验研究

为深入研究PEC柱-钢梁组合框架结构体系的抗震性能,设计了1榀两层单跨钢板组合截面PEC柱-削弱截面钢梁组合框架1∶2缩尺试件,并对其进行了低周往复荷载抗震试验。根据实测数据整理,得到了试验滞回特征曲线,并结合试验过程现象记录,分析了试件滞回特性、抗侧刚度退化规律、节点连接性能、耗能与延性和试件破坏模式等力学性能。研究结果表明:试件结构具有较高的承载力和较大的抗侧刚度;采取梁端截面削弱方式可实现梁端塑性铰位置远离节点区,且端板对穿螺栓连接能有效将梁端受拉翼缘拉力转化为对应边对节点区的压力,使得节点区形成了混凝土斜压带传力模式,提高了节点区抗震性能;试件滞回曲线较为饱满,在梁翼缘与端板连接焊缝存在施工缺陷情况下,其整体侧移、延性系数和等效黏滞阻尼比分别达到3.50%(推)/4.50%(拉)、2.92(推)/3.21(拉)和0.306,且承载力仍未下降至其极限承载力的85%,即试件结构具有良好的变形、抗震延性与耗能能力;该试件在循环往复荷载下呈现的破坏模式为梁削弱截面部位和PEC柱脚相继形成塑性铰的塑性机构。     

Carbon nanotubes-incorporated MIL-88B-Fe as highly efficient Fenton-like catalyst for degradation of organic pollutants

CNTs were incorporated into MIL-88B-Fe to get a new Fenton-like catalyst (C@M). Fe(II) was introduced in C@M to get a fast initiation of Fenton-like reaction. Fe(II) content in C@M was related with oxygen-containing functional groups on CNTs. C@M shows efficient catalytic degradation of pollutants over a wide pH range. Iron-based metal organic frameworks have been verified to be efficient heterogeneous Fenton catalysts due to their open pore channels and highly uniform distribution of metallic centers. In these catalysts, however, the iron element is mainly in the form of Fe(III), which results in a process required to reduce Fe(III) to Fe(II) to initiate Fenton reaction. To address this problem, carbon nanotubes (CNTs) with electron-rich oxygen-functional groups on the surface were incorporated into the metal organic frameworks (MIL-88B-Fe) to improve Fe(II) content for an enhanced Fenton-like performance. The prepared CNT@MIL-88B-Fe (C@M) showed much stronger catalytic ability toward H₂O₂ than MIL-88B-Fe. The pseudo-first-order kinetic constant for phenol degradation by C@M (0.32 min^–1) was about 7 times that of MIL-88B-Fe, and even higher than or comparable to the values of reported heterogeneous Fenton-like catalysts. Moreover, the Fenton-like system could effectively degrade various kinds of refractory organic pollutants and exhibited excellent catalytic activity over a wide pH range (4–9). XPS analysis confirmed that Fe(II) content of the catalyst gradually increased with CNT loadings. Electron spin resonance analysis showed that the signal intensity (•OH) of C@M was much higher than MIL-88B-Fe, which was consistent with the degradation efficiency of pollutants. Furthermore, the Fe(II) content of the catalyst gradually increased along with the oxygen-functional group content of CNTs. The result demonstrated that oxygen-containing functional groups of CNTs have a significant impact on the enhanced catalytic performance of C@M. This study provides a new insight to enhance Fenton reaction by using nanocarbon materials.     

Adsorption of Ammonium by Graphene Oxide-Based Composites Prepared by UV Irradiation and Using as Slow-Release Fertilizer

A novel sodium alginate-grafted poly(acrylic acid)/graphene oxide (NaAlg-g-PAA/GO) composite hydrogel was prepared via ultraviolet irradiation, and characterized by infrared spectroscopy spectrometer. X-ray diffraction, X-ray photoelectron spectroscopy and scanning electron microscopy. It was employed to adsorb NH₄⁺ from aqueous solution and used as slow-release nitrogen fertilizers (SNFs). Result indicated that the adsorption process for NH₄⁺ reached equilibrium within 50 min, with the adsorption capacity of 6.6 mmol g^?1 even if 30 wt% GO was incorporated. The results of adsorption kinetic and isotherm were well described by the pseudo-second-order and Freundlich model. The thermodynamics analysis showed the adsorption process was spontaneous. The study indicated excellent water-holding ratio of soil with 2 wt% SNFs was 81.2%, and nitrogen release was up to 55.1% within 40 days in soil. Overall, NaAlg-g-PAA/GO could be considered as an efficient adsorbent for the recovery of nitrogen with the agronomic reuse as a fertilizer.     

红壤和磷灰石对沉积物重金属稳定化的影响

利用磷灰石、红壤及两者复配组合对污染沉积物中重金属进行稳定化处理,通过TCLP和改进的BCR连续提取法对稳定化效果进行分析和评价。结果表明,在稳定化试验中,对Cu、Cd和Zn的稳定效果由大到小为红壤+磷灰石、磷灰石、红壤;其中,红壤+磷灰石对Pb的稳定效果与磷灰石单独添加相近,显著大于红壤。5%磷灰石+5%红壤添加3个月后,Cu、Cd、Zn和Pb的稳定效率分别达到59.83%、29.43%、31.00%、96.06%。添加5%磷灰石时,Cu、Cd、Zn和Pb的稳定效率分别为52.46%、24.67%、25.23%、96.06%。红壤的添加不同程度地促进了磷灰石对Cu、Cd和Zn的稳定效率。连续提取试验结果表明.磷灰石单独和复配添加均使Cu、Zn和Pb的生物可利用态和潜在生物可利用态占比降低,生物不可利用态占比增大。5%磷灰石+5%红壤处理中,Cu、Cd、Zn和Ph的生物可利用态和潜在生物可利用态的比例总和分别降低了19.31%、5.11%、20.11%和68.97%。相比磷灰石单独处理,复配处理进一步促进了Cd和Zn的酸溶态向残渣态转化。磷灰石和红壤+磷灰石复配处理能有效降低沉积物中重金属的危害。     

一种新的快速测定水中COD的消化一分光光度法

探讨了在MnSO_4-CuSO_4复合催化剂、硫-磷混酸体系中,对样品进行恒温密封消解,用分光光度法测定溶液的COD值。实验得出测定化学需氧量的最佳条件:混酸H_2SO_4-H_3PO_4体积比为4:1,催化剂MnSO_4-CuSO_4质量比为1:2,MnSO_4-CuSO_4的总量为0．03g,消解温度为165℃,消解时间为15min。实验结果表明,此方法的测定结果与重铬酸钾法测定结果的相对误差≤5%,且有较好的重现性及较高的准确度与精密度。本法可同时消解多个试样,适用于大批量试样COD的测定,使试样的消解时间由标准法的2h缩短到了15min,同时用MnSO_4-CuSO_4复合催化剂代替价格昂贵的A_(g2)SO_4,大大降低了分析成本。     

车用汽油铅损害及其对策研究

针对车用汽油的抗爆性能要求,探讨四乙基铅（Ｐｂ（Ｃ２Ｈ５）４）抗爆添加剂的作用机理,并着重分析研究了由此而引起的发动机铅排放对人类造成的损害及给大气环境等带来的污染。还探讨了车用汽油铅损害的对策及其最新进展     

汽车左/右后轮罩冲压工艺及翻边、斜楔翻边模具设计

根据制件的特点 ,分析了其冲压成形的工艺难点 ,制定了合理的工艺 ,简化了模具设计和制造 ,并画出了制件的综合工序图 ,分析了各工序内容和工艺特点 ,说明了各工序模具设计的关键问题。同时以第 5道工序为例 ,重点分析了斜楔翻边、翻边模的结构、工作原理及设计要点