EGR与富氢进气对柴油机性能和排放的影响

试验研究了利用EGR加富氢进气改善ZS195型柴油机性能和排放的可行性,在标定转速下试验研究了不同EGR率、掺氢率对ZS195型柴油机工作过程、排放和经济特性的影响.研究结果表明:在高负荷工况,当EGR率一定时,随着掺氢率的增加,缸内峰值压力和压力升高率峰值增加.EGR加富氢进气可以降低HC、CO排放量和烟度,但NO_x排放量有所增加.ZS195型柴油机采用EGR技术后,富氢进气会提高缸内混合气的燃烧速度,改善缸内燃烧质量,发动机的热效率有所增加.     

海绵中氯丙酸脱氯微生物的分离及其初步研究

以氯丙酸为单一碳源,通过富集培养从大连海域繁茂膜海绵中分离筛选得到139株氯丙酸降解菌。经过初步筛选得到35株降解能力较强的菌株。对这些菌株的耐盐试验表明,分离到的大部分菌株均具有较强的盐耐受能力,多数菌株为中度嗜盐菌。其中部分菌株可以在14.6%以上盐度培养基中生长,可能为极端嗜盐菌。多底物降解试验表明,大多数菌株均能降解多种底物,这些菌株可用于有机氯污染环境生物修复。同时也说明海绵对水体中有机氯污染物具有去除作用。     

近地层臭氧浓度升高对常规稻颖花形成的影响：FACE研究

FACE(free air gas concentration enrichment)研究使用标准的作物管理技术,在完全开放的大田条件下运行,代表了目前人类对未来大气环境的最好模拟。利用独特的大型稻田FACE平台,以典型的常规水稻品种武粳15(粳稻)和扬稻6号(籼稻)为供试材料,研究近地层臭氧(O3)浓度升高(比大气背景臭氧浓度平均增高26%)对常规水稻颖花形成的影响。结果表明:(1)高浓度O3对供试品种全穗以及一、二次枝梗颖化分化数均无显著影响;(2)高浓度O3使供试品种全穗和二次枝梗颖花退化数和退化率均显著增加,颖花退化增多是由于现存一次枝梗上二次枝梗大量退化而引起的二次颖花退化所造成;(3)颖花退化数在颖花分化数中所占比例很低,故高浓度O3对两供试品种全穗和一、二次枝梗颖花现存数以及稻穗构成均无显著影响。结合前报可知,选用常规水稻品种以及增施保花肥可能是未来近地层高浓度O3环境下稻作生产重要的适应措施。     

生物质炭添加对生菜Cd积累的影响

为探究添加生物质炭对Cd胁迫下生菜Cd吸收累积的影响,以生菜为试验材料,通过盆栽试验,在添加外源镉含量为3 mg/kg的土壤中分别添加0%、1%、2%、3%的生物质炭,待生菜收获后,测得土壤pH、有机碳、生菜产量、生菜体内Cd富集和转运情况及Cd在土壤中的赋存形态的数据。结果表明：添加生物质炭可以显著提高土壤有机碳含量(P≤0.05),其中生物质炭添加量为3%,相比CK组土壤有机碳增加了35.14%～40.87%;添加生物质炭可以显著降低生菜Cd含量,尤其是3%量的生物质炭添加后,生菜叶Cd含量由0.79 mg/kg降低至0.44 mg/kg。生物质炭可以显著降低生菜中Cd的富集、转运系数,并使残渣态Cd含量增多,酸可提取态、可还原态、可氧化态Cd含量显著降低。因此,生物质炭的施用对Cd污染土壤和生菜体内Cd的积累有显著的阻控作用,特别是生物质炭添加量为3%时效果最优。     

Effect of cultivation methods on nutritional enrichment of euryhaline rotifer <Emphasis Type="Italic">Brachionus plicatilis</Emphasis>

This study aimed at comparing fatty acid contents of rotifers cultured with different methods after nutritional enrichment in order to evaluate the rotifer quality produced by these methods. Rotifers were cultured using either a batch or a continuous culture. From the batch culture, three experimental subpopulations were used, sampled from the culture at 1, 24, and 48 h after rotifer inoculation. The continuous culture was performed with two tanks; one was for cultivation with continuous feeding and water supply (cultivation tank), and another was for harvesting from the cultivation tank by overflow (harvest tank). From the continuous culture, two subpopulations were used: one from the cultivation and one from the harvest tank. Nutritional enrichment was performed after each culture. Each population was enriched with Nannochloropsis oculata or a commercial enrichment diet. When the enrichment was performed with N. oculata on populations at 24 h after inoculation originating from either of the two tanks of continuous culture or the batch culture tank, a higher quantity of arachidonic acid (ARA) and eicosapentaenoic acid (EPA) was obtained from the two tanks of continuous culture. The same results were obtained when enrichment diet was used, this time including docosahexaenoic acid (DHA).     

3种植物对镉污染土壤修复的试验研究

为探究植物修复技术在济源镉(Cd)污染土壤的应用特征和效果,笔者以不同Cd污染程度的实际土壤为对象,采用盆栽试验,对比三叶鬼针草、黑麦和印度芥菜对Cd的耐受、富集、转移能力及修复效率。结果表明：污染组植物的生物量无显著下降,供试植物均具有较强的Cd耐性。3类植物富集特征不同,地上部分富集Cd浓度顺序依次是：三叶鬼针草＞印度芥菜＞黑麦。3种植物中黑麦地下部分Cd含量最高,轻、重度污染组的Cd含量分别达到11.95 mg/L、28.56 mg/L。三叶鬼针草对Cd具有较强的转移能力,其中在轻度污染土壤中转移系数(TF=2.23)最大。此外,三叶鬼针草修复效率最高,轻、重度污染组分别为2.04%、1.59%。综上所述,三叶鬼针草的生物量、富集转运系数和修复效率均高于黑麦和印度芥菜。因此,三叶鬼针草可作为济源Cd污染土壤修复植物之一,为当地土壤Cd污染治理提供理论指导和技术依据。     

Growth,survival rate and fatty acid composition of sterlet (Acipenser ruthenus) larvae fed fatty acid‐enriched Artemia nauplii

We evaluated the growth and survival rate of sterlet (Acipenser ruthenus) larvae fed Artemia nauplii enriched with Olioω3 or Red Pepper commercial emulsions (BernAqua NV, Belgium). Sterlet larvae, 0.022 ± 0.002 g body weight, were randomly assigned to one of three feeding regimes with two different feeding durations. After administering live feed for 7 or 14 days, larvae were weaned onto commercial food and reared to 36 days posthatching (28 days of feeding). There were no significant differences in body weight among groups at the end of the trial. A significantly higher survival rate (p < 0.05) was observed in larvae fed Artemia enriched with Red Pepper for 14 days compared to other feeding regimes. Based on the analysis of growth parameters, we can conclude that 7 days of live feeding to be sufficient for efficient rearing of sterlet larvae. And longer duration of live feeding with use of special enrichment can be recommended for a higher survival rate.     

Successful rearing of whiteleg shrimp Litopenaeus vannamei larvae fed a desiccation‐tolerant nematode to replace Artemia

The nematode Panagrolaimus sp. was tested as live feed to replace Artemia nauplii during first larval stages of whiteleg shrimp Litopenaeus vannamei. In Trial 1, shrimp larvae were fed one of four diets from Zoea 2 to Postlarva 1 (PL1): (A) Artemia nauplii, control treatment; (NC) nematodes enriched in docosahexaenoic acid (DHA) provided by the dinoflagellate Crypthecodinium cohnii; (N) non‐enriched nematodes; and (Algae) a mixture of microalgae supplemented in C. cohnii cells. In Trial 2, shrimp were fed (A), (NC) and a different treatment (NS) with nematodes enriched in polyunsaturated fatty acids (PUFAs) provided by the commercial product S.presso^®, until Postlarva 6 (PL6). Mysis 1 larvae fed nematodes of the three dietary treatments were 300 μm longer (3.2 ± 0.3 mm) than control larvae. At PL1, control shrimp were 300 μm longer (4.5 ± 0.3 mm) than those fed DHA‐enriched or PUFAs‐enriched nematodes. No differences were observed in length and survival at PL6 between control larvae and those fed DHA‐enriched nematodes (5.1 ± 0.5 mm; 33.1%–44.4%). Shrimp fed microalgae showed a delay in development at PL1. This work is the first demonstration of Panagrolaimus sp. suitability as a complete substitute for Artemia in rearing shrimp from Zoea 2 to PL6.     

Effects of thyroxine,cod liver oil and potassium iodide on growth and survival of juvenile seahorse,Hippocampus barbouri

Low survival at early stage is the bottleneck in seahorse aquaculture, particularly in the feeding aspect since newborn seahorses must feed immediately upon birth to sustain themselves. Seahorses are visual predator, therefore preferred live feed such as zooplankton. In aquaculture, the most common live feed used is Artemia. In this study, two experiments were conducted to determine the effect of different Artemia enrichment on the growth and survival of newborn Hippocampus barbouri. In the first experiment, six treatments using Artemia enriched with Culture Selco Plus? (SELCO), thyroxine (T4), potassium iodide (KI), cod liver oil (CLO), cod liver oil in combination with thyroxine (CLO + T4) and potassium iodide (CLO+KI) were fed to newborn H. barbouri. Newly hatched Artemia were used as control. At the end of first experiment, treatments using CLO + T4 produced juvenile H. barbouri with the best (p < .05) wet weight (0.142 ± 0.000 g), while juvenile in treatment CLO+KI recorded the highest (p < .05) standard length (3.947 ± 0.014 cm). Subsequently, a second experiment was carried out using the two best enrichment (CLO + T4 and CLO + KI) from the first experiment, but given at different frequency (daily, twice a week, once a week, once in 2 weeks). Daily enrichment using both CLO + T4 and CLO + KI showed no significant (p > .05) difference in growth performance and survival of juvenile of H. barbouri. Interestingly, juvenile fed CLO + T4 enriched Artemia at frequency of twice a week also has no significant difference (p > .05) in survival and growth performance (except for final standard length) when compared with treatment CLO + T4 at daily frequency.     

农作物和园艺作物富硒效应研究进展

硒被证实是动物必需的营养元素,环境中硒过量或缺乏均会导致人体和动物产生疾病.近年来国内外有关植物富硒研究多有报道,特别是有关农作物及园艺植物富硒研究资料较多.通过综合相关文献,综述了国内近年来有关农作物和园艺作物施硒的研究现状、作用机理、应用现状以及富硒研究的最新进展.