2018年春季和夏季莱州湾营养盐结构及限制特征

根据2018年5、8月莱州湾的生态调查资料，采用营养盐限制法则及潜在性富营养化评价模式等方法，对莱州湾无机氮(DIN)、活性磷酸盐(PO34–-P)和硅酸盐(SiO23–-Si)的平面分布、结构及限制特征进行了分析。结果显示，2018年5、8月莱州湾的DIN浓度范围为1.64~106.36 μmol/L，平均值为24.18 μmol/L，5月明显高于8月；PO34–-P浓度范围为0~2.010 μmol/L，平均值为0.182 μmol/L，8月明显高于5月；SiO23–-Si浓度变化范围为0.97~78.93 μmol/L，平均值为18.30 μmol/L，8月明显高于5月。DIN、PO34–-P、N/P高值区主要位于莱州湾西部的小清河口和黄河口附近海域；SiO23–-Si、Si/N、Si/P高值区主要位于湾底部、龙口–莱州近岸海域。对营养盐结构的分析表明，莱州湾存在明显的磷限制和枯水期的硅限制，陆源输入是莱州湾营养盐的主要来源。营养盐结构限制平面分布表明，春季莱州-招远养殖区和夏季东营-潍坊养殖区易引发赤潮，夏季莱州–招远养殖区初级生产力受到一定限制，对养殖业造成一定的影响。     

基于毛细管网的日光温室主动式集放热系统研究

为了对比日光温室传统保温蓄热后墙与基于毛细管网的主动式集放热系统（AHSCTM）的集放热性能，对AHSCTM的集放热性能进行了测试，构建了AHSCTM水温模型，利用一维差分法对相同环境条件下的外保温复合墙（370mm黏土砖和100mm聚苯乙烯板复合而成）日间储热量和夜间放热量进行了模拟。结果表明，AHSCTM的日间储热量和夜间放热量分别为相同条件下外保温复合墙的84.4%~111.3%和74.8%~100.7%，AHSCTM的COP（Coefficient of performance）为1.1~2.4。在夜间运行期间，AHSCTM放热量是相同时间段内外保温复合墙的98.2%~172.5%。因此，与外保温复合墙相比，AHSCTM有利于提高室内最低气温。改进AHSCTM的日间储热量和夜间放热量得到大幅提升，分别较外保温复合墙高67.6%~112.1%和69.0%~128.3%，COP可达2.8~7.0。改进AHSCTM的储放热性能优于外保温复合墙，说明利用改进AHSCTM配合保温墙体替代传统保温蓄热后墙是可行的。     

一种改进的CRLP最大许用操作压力设计方法

与传统管线钢管相比,复合材料增强管线钢管(CompositeReinforcedLinePipe,CRLP)具有承压能力高和质量轻等优势,但对其压力设计的研究尚不充分。CSAZ662-2015《油气管道系统》和GB/T35185—2017《石油天然气工业用复合材料增强管线钢管》中最大许用操作压力的设计思路不同,且设计结果差别较大。针对此问题,基于组合薄壁圆筒模型对承压CRLP进行分析,对最大许用操作压力下材料的名义许用应力和真实许用应力进行了区分,进而导出真实许用应力的显式表达形式,并以此作为设计安全裕度的评价指标。分析表明:现有规范和标准中的设计公式均无法保证管线钢和复合材料的真实许用应力为常量,对应两种设计方法,各组分材料的真实许用应力均随CRLP规格差异而发生变化,并且随着试压/预应力处理的历程而改变。基于上述分析和CRLP极限状态下的承载特征,提出一种改进的压力设计方法。新方法优先保证复合材料的真实许用应力为常量,并可由设计系数直接确定;在最大许用操作压力的计算中,考虑了加载历程的影响,物理意义明确。算例表明,其设计安全裕度较现有方法更为合理,对于CRLP压力设计的改进有参考价值。     

蒙脱土-稻壳炭复合材料对Pb(Ⅱ)吸附特性研究

采用静态吸附实验,研究蒙脱土-稻壳炭复合材料对Pb~(2+)的吸附动力学和热力学特性,并考察吸附剂用量、共存离子及pH等因素对该复合材料吸附Pb~(2+)的影响。结果表明,复合材料对Pb~(2+)的吸附特性符合准二级动力学模型,等温吸附过程能较好地以Freundlich模型进行拟合,且是以物理吸附为主的自发的吸热反应。复合材料对Pb~(2+)的吸附量随吸附时间的延长先快速增加,后缓慢增加最终达到吸附平衡,且随着复合材料投加量的增加,Pb~(2+)的去除率增大。复合材料对水溶液中Pb~(2+)的吸附性能在pH为5时较好,吸附量达52.79 mg·g~(-1);不同浓度Ca~(2+)、Mg~(2+)均会对Pb~(2+)的吸附反应产生抑制作用,且Mg~(2+)的抑制作用更强。     

柠檬酸强化低浓度EDTA对成都平原农田土壤铅和镉的淋洗效率

为了寻找绿色高效的土壤重金属修复技术,研究了柠檬酸与低浓度EDTA不同组合方式对成都平原两类污染农田土壤中Pb和Cd的淋洗率,并测定了淋洗前后土壤中有机质和基础养分含量。结果表明,EDTA单独淋洗时对水稻土Pb、Cd的最高淋洗率为44.94%和88.32%,对紫色土Pb、Cd的最高淋洗率为48.48%和71.85%。柠檬酸单独淋洗时对水稻土Pb、Cd的最高淋洗率为24.71%和69.38%,对紫色土Pb、Cd的最高淋洗率为33.54%和59.77%。柠檬酸与低浓度EDTA复合淋洗效果均优于单独淋洗,其中先EDTA再柠檬酸淋洗组合效果最好。相较于EDTA单独淋洗,该组合方式将水稻土中Pb、Cd的淋洗率分别提高了6.07%和9.67%,将紫色土中Pb、Cd的淋洗率均提高了10.33%和14.73%。同时,复合淋洗还能减少10%以上的土壤有机质与基础养分的流失。综合淋洗效率和土壤有机质及养分的变化,先用EDTA淋洗再用柠檬酸淋洗是最佳淋洗组合。     

A fluorescence‐based assay for in vitro screening of Saprolegnia inhibitors

The incidence of fish pathogenic oomycetes, Saprolegnia, has increased significantly in aquaculture since the ban of malachite green. For the efficient characterization of anti‐Saprolegnia therapeutics, simple accurate methods are required. However, the current screening methods are limited by time, and none of them are confirming the viability of treated spores or hyphae. In this study, a modified fluorescence‐based assay for the in vitro screening of Saprolegnia inhibitors has been developed. This method involves the use of FUN‐1 viability dye combined with calcofluor white M2R, and is based on the formation of orange‐red cylindrical intravacuolar structures (CIVS) in metabolically active spores, hyphae and biofilms. Heat‐killed and bronopol‐treated Saprolegnia spores, hyphae and biofilms exhibited diffuse bright green fluorescence which confirms complete loss of viability. For boric acid‐treated spores, no germination was observed. However, tiny CIVS were observed in 50% of treated spores which indicated reduction in their viability. Our results proved that FUN‐1 dye is an efficient tool to distinguish between live and dead Saprolegnia spores, hyphae and biofilms and to monitor the change in Saprolegnia viability during qualitative evaluation of potential anti‐Saprolegnia compounds.     

Influence of nanochitosan/zeolite composite on growth performance,digestive enzymes and serum biochemical parameters in rainbow trout (Oncorhynchus mykiss)

Protective effects of nanochitosan/zeolite composite besides zeolite and chitosan/zeolite composite on rainbow trout growth, digestive enzyme activities and biochemical parameters were studied. Nanochitosan/zeolite hybrid composites with three different ratio of nanochitosan:zeolite (35:100, 3.5:100 and 0.35:100) were synthesized and analysed by X‐ray powder diffraction (XRD), thermal gravim (TG) analysis and scanning electron microscope (SEM) methods. Prepared composites as well as zeolite and control diets were fed to rainbow trout (50 g) for a period of 60 days. The addition of treated diets significantly improved growth performance compared to the control diet. Supplemental zeolite could only enhance the amylase activity in fish intestine, whereas other treatment groups could increase the pepsin activity besides intestinal alkaline phosphatase, trypsin and amylase activities. No differences were observed for intestinal acid phosphatase and lipase activities among the experimental diets. Meanwhile, serum total antioxidant activity and lipid peroxidation product, indicated by malondialdehyde (MDA), significantly increased and decreased, respectively, with some doses of administration, indicating the elevated antioxidant status in treatment groups. Serum‐specific marker enzymes, namely aspartate aminotransferase (AST) and alkaline phosphatase (ALP), were not affected in all groups. Meanwhile serum total protein in most treatment groups was significantly higher than the control group. Results showed that synthesized composites especially nanochitosan/zeolite composite at 5 g/kg had potential to enhance growth performance, digestive enzyme activities and some biochemical parameters in rainbow trout.     

长链酰胺化纳米纤维素增强聚乳酸复合材料

以纳米纤维素(NCC)为原料,先采用四甲基哌啶氮氧化物(TEMPO)氧化制备氧化纳米纤维素(TONC),再与不同链长脂肪胺在催化剂作用下发生反应,得到脂肪胺改性纳米纤维素,当脂肪胺为十二胺(DOA)、十四胺(TEA)、十六胺(HEA)、十八胺(OCA)时,分别制得DOATONC、TEATONC、HEATONC和OCATONC。傅里叶变换红外光谱(FT-IR)、X射线衍射(XRD)和元素分析表明:脂肪链接枝成功,改性后纳米纤维素的晶形没有发生改变,为原有Ⅰ型晶型;接触角和分散性测试表明:随着脂肪链的增长,改性纳米纤维素表面的亲水性明显下降(接触角由65.8°上升至93.9°),而分散率由25.17%先降至11.97%,再升至71.71%。将1%的改性纳米纤维素添加到聚乳酸(PLA)中制得复合膜,机械性能测试结果表明:随着脂肪链的增长,复合膜的机械性能明显提高,其中PLA/OCATONC复合膜的拉伸强度和断裂伸长率分别达到40.2 MPa和6.39%。     

竹木复合建筑混凝土模板的工艺研究

以火车集装箱底板加工剩余物为原料,经过去贴面、磨砂等简单的处理后与杨木单板重组成一种层层交错结构的竹木复合建筑混凝土模板。用单因素实验方法,分析不同热压工艺参数下的静曲强度、弹性模量、含水率,从而确定热压温度、压力、时间的工艺参数范围。用正交实验法测试静曲强度、弹性模量、湿态胶合强度、密度等性能,并进行了方差分析和平均值分析。结果表明:与传统建筑混凝土模板制备方法相比,该工艺省去了去竹青、竹黄、竹节和软化等复杂的竹片材料制备方法。成品的竹材加工剩余物的体积利用率占竹木复合建筑混凝土模板的80%以上,同时节约了生产成本。通过极差分析,热压工艺因素对静曲强度、弹性模量、湿态胶合强度的影响程度都是:热压压力>热压时间>热压温度。通过平均值分析,最优热压参数为:3 MPa、50 s·mm^-1、135℃。     

5种稳定剂对土壤中4种重金属的稳定效果

采集被重金属As、Cd、Pb和Zn污染的土壤,选用SiO_2、CaO、CaCO_3、FeSO_4和绿肥5种稳定剂对土壤重金属进行稳定化试验。结果表明:施用单种稳定剂时,FeSO_4对土壤中As的稳定效果最明显,CaO和CaCO_3对土壤Cd、Pb、Zn的稳定效果相对较好,绿肥的稳定效果最差,且5种稳定剂均是随着添加比例的增加对土壤中重金属的稳定效果越好;同时施用2种稳定剂时,FeSO_4和CaO与FeSO_4和CaCO_3均具有较高的稳定效率,3%FeSO_4和3%CaO能达到同时修复As、Cd、Pb、Zn的效果;先后施用FeSO_4和CaO 2种稳定剂时,先加入FeSO_4时,土壤中4种重金属As、Cd、Pb、Zn的稳定效率分别为92.07%、31.08%、27.35%、53.91%,而先加入CaO时,4种重金属As、Cd、Pb、Zn的稳定效率分别为88.21%、40.14%、29.81%、55.12%。可见,在稳定多种重金属时,除了考虑稳定剂的不同配方及比例外,还应考虑添加顺序等。