改进粒子群优化（MPSO）算法在动     

罗志平  周新志  王标 《中国农村水利水电》2007,(6):43-45

基于在水资源不充足的情况下，对都江堰灌区六大渠干水资源的合理分配，使农业效益达到最大。首先建立灌区优化配水模型，并将粒子群优化算法（PSO）及其改进的算法应用于该模型。分别对标准PSO、两种改进PSO（MPSO）算法与遗传算法进行仿真对比，结果显示采用PSO算法及其MPSO在农业经济效益上可获得更好的寻优效果，提高了水资源的利用率。  相似文献   

改性木质素对砖红壤磷素有效性的影响   总被引：5，自引：0，他引：5  

郑超刘可星  廖宗文杜建军 《华中农业大学学报》2004,23(5):528-532

磷肥施入砖土壤后，土壤速效磷随着时间的推移，呈现下降的趋势。利用改性木质素缓释磷铵，可以有效地络合土壤活性钵，降低其活性，从而阻止土壤速效磷被固定，使土壤磷素维持在较高的水平。土壤中交换性钙和交换性镁对土壤速效磷的影响不大。  相似文献   

气调包装复合保鲜技术在水产品保鲜中的应用现状     

谢晶  李沛昀  梅俊 《上海海洋大学学报》2020,29(3):467-473

水产品营养价值高,含有多种氨基酸、不饱和脂肪酸、矿物质等营养素而脂肪含量相对较低,深受人们喜爱,也是中国居民膳食指南中的重要组成部分。水产品中由于水分、蛋白质等成分含量丰富,极易在微生物和内源酶的作用下发生蛋白质、脂肪等的降解或氧化而腐败变质,从而缩短了货架期,降低了商业价值。气调包装保鲜技术是指通过使用高阻隔性能的复合包装材料,并调整食品贮藏环境中的气体组成来改善食品贮藏品质并延长货架期的技术,因其安全性高、保鲜效果好而被广泛应用于水产品保鲜领域中,本文总结了近几年气调包装复合其他保鲜技术(低温、紫外杀菌、臭氧处理、超高压处理、化学保鲜剂、生物保鲜剂)在水产品保鲜领域中的应用,旨在为气调包装在水产品保鲜中的进一步应用提供理论依据。已有的研究表明该复合技术能有效地降低水产品贮藏末期微生物总数、挥发性盐基氮、三甲胺、生物胺等指标,并维持较高的感官评分、水分含量、鲜度值,可有效延长水产品的货架期,未来可以从气调包装复合保鲜技术的抑菌机理、理化指标变化机理、包装材料及模式等方面展开深入研究。  相似文献   

巴基斯坦转基因作物发展概况          下载免费PDF全文

孙卓婧  段亚光  吴季荣  彭晨 《农学学报》2020,10(2):81-84

近年来,发展中国家在转基因技术与商业化发展上取得了巨大进展。巴基斯坦是同中国有着深厚友谊的国家,是“一带一路”政策亚欧非大陆的重要一站。本文介绍了巴基斯坦转基因技术发展现状及转基因商业化情况,研究其管理框架及政策变化等,分析其在政策、监管、知识产权、消费者认知度等方面存在的问题。研究结果对中国转基因政策的制定具有借鉴意义。  相似文献   

Rapid screening of genetically modified ingredients in soybean and cotton processing by-product and waste using direct qPCR     

《中国油料作物学报(英文)》2020,5(3):142-148

To develop a simple and fast method for screening genetically modified ingredients from processing by-product and waste, direct quantitative PCR (qPCR) kit-Taqman which omitting multi genomic DNA preparing steps was developed in this study. A total of 18 oil crop processing by-products and wastes including 10 soybean and 8 cotton materials were collected from food processing factories. Compared with 2 commercial direct qPCR kits, conditions of DNA releasing procedure and PCR amplification were optimized. Element screening was performed at the initial step of genetically modified (GM) ingredient testing procedure via direct qPCR. GM event identification was carried out in positive samples by initial screening. Totally 5 screening elements (P–35S, T-NOS, Cp4-epsps, bar and pat) for soybean materials and 6 screening elements (P–35S, T-NOS, NPTII, Cry1Ac, bar and pat) for cotton samples were detected. In GM event identification, MON531 and MON1445 were found in cotton materials. Results were further confirmed by real-time PCR with DNA extraction and purification. The direct qPCR system proposed by this research was convenient for rapid screening and identification of GM ingredients in oil crop primary by-product and waste.  相似文献   

不同改良材料对灌漠土微生物量磷及生物有效性的影响     

谭雅茹  张育林  王旭东 《干旱地区农业研究》2020,38(6):98-104

通过培养和盆栽试验,向灌漠土土壤中加入等量磷和不同添加比例的硫磺S（0.05%、0.15%、0.45%）、生物菌肥B（0.25%、0.50%、1.00%）、有机肥OM（0.50%、1.00%、2.00%）和小麦秸秆WS（1.00%、2.00%、4.00%）,研究不同改良材料配施磷肥土壤微生物量磷的变化特征,及其与Olsen P、小麦吸磷量之间的关系。结果表明,添加不同改良材料处理的土壤微生物量磷含量均显著高于对照（不添加改良材料）,且随着添加比例的增大而增加。在第16天时,各处理土壤微生物量磷含量达到最大值,OM₂2.00、B₂1.00、WS₂4.00和S₂0.45处理分别较对照显著增加了34.66%、34.52%、28.19%和23.89%;经过30 d的培养,硫磺、生物菌肥、有机肥和小麦秸秆处理的土壤微生物量磷含量较对照分别增加了19.51%、43.08%、47.92%和41.68%。在一定范围内（Olsen P约90 mg·kg^-1）,土壤微生物量磷随土壤Olsen P提高而增加。在培养的第16天和第30天时,小麦植株吸磷量也与土壤微生物量磷存在极显著的相关关系。总体看来,有机肥或生物菌肥配合磷肥施用于灌漠土能促进土壤微生物量磷的增加,提高磷的生物有效性,对于灌漠土磷素高效利用具有重要意义。  相似文献   

Critical PO2 as a diagnostic biomarker for the effects of low‐oxygen modified and controlled atmospheres on phytosanitary irradiation treatments in the cabbage looper Trichoplusia ni (Hübner)     

Chao Chen  Catriona H Condon  Leigh Boardman  Robert L Meagher  Laura A Jeffers  Andrea Beam  Woodward D Bailey  Daniel A Hahn 《Pest management science》2020,76(7):2333-2341

  相似文献   

Minimally modified low-density lipoprotein up-regulates endothelin receptors in mouse mesenteric artery through p38 MAPK pathway     

XIE Xi  CHEN Chen  LIN Jie  TANG Hong-xia  QIN Xu-ping  LI Jie 《园艺学报》2020,36(5):779-787

AIMTo investigate whether minimally modified low-density lipoprotein (mmLDL) affects the quantity and activity of endothelin （ET） type A (ET_A) and type B (ET_B) receptors in mouse mesenteric artery by activating p38 mitogen-activated protein kinase (MAPK) inflammatory pathway. METHODSThe KM mice were divided into normal saline (NS) group (injection of NS via caudal vein), mmLDL group (injection of mmLDL via caudal vein), LDL group (injection of LDL via caudal vein), mmLDL+SB 203580 group (injection of mmLDL via caudal vein and intraperitoneal injection of p38 MAPK pathway specific inhibitor SB 203580) and mmLDL+DMSO group (injection of mmLDL via caudal vein and intraperitoneal injection of DMSO). Mesenteric artery ring segment vasoconstriction dose-response curves affected by sarafotoxin 6c (S6c) and ET-1 were recorded by the myography system. The mRNA levels of ET_B receptor, ET_A receptor and interleukin-6 (IL-6) were detected by RT-qPCR. The protein levels of ET_B receptor, ET_A receptor, IL-6, p38 MAPK, p-p38 MAPK, NF-κB and p-NF-κB were determined by Western blot. The serum concentration of IL-6 was measured by ELISA. RESULTSThe contractile responses of the blood vessel segments to S6c and ET-1 were significantly increased by mmLDL (P<0.01). The mRNA and protein expression levels of ET_A receptor, ET_B receptor, and IL-6 significantly increased (P<0.01). The protein levels of p-p38 MAPK and p-NF-κB were significantly increased (P<0.01). The serum level of IL-6 was significantly increased (P<0.01). These effects of mmLDL were inhibited by p38 MAPK inhibitor SB 203580. CONCLUSION mmLDL increses the serum concentration of IL-6, up-regulates the expression of IL-6, ET_A receptor and ET_B receptor in mouse mesenteric artery, and enhances the vasoconstriction function medi?ated by ET_A and ET_B receptors, which is related to the activation of p38 MAPK inflammatory pathway and downstream NF-κB pathway.  相似文献   

氨基修饰二氧化硅对Cr^3+和直接桃红B12的吸附     

李琼  胡育  宋连香  刘素君  王应红 《中国沼气》2020,(1):49-52

该试验以硅烷偶联剂KH-550为改性剂,乙醇为溶剂合成氨基二氧化硅。利用红外光谱、扫描电镜、原子吸收光谱、可见分光光度法对改性前后SiO 2进行表征,研究其对铬离子及染料直接桃红B12的吸附情况。结果表明:25℃恒温振荡20 min,改性SiO 2吸附重金属离子Cr^3+效果明显,当其用量为0.04 g时,吸附率达99.01%,而相同条件下未改性SiO 2对Cr^3+吸附率只有25.13%;将其用于染料直接桃红B12的吸附,改性后SiO 2吸附率达91.97%,相同条件下未改性SiO 2的吸附率仅为34.23%。  相似文献   

养猪场沼渣制备包膜缓释肥理化性质表征     

刘筱  黄彬  胡林潮  毛林强  张文艺 《中国沼气》2020,(1):85-90

文章以分散式养猪场沼渣为应用研究对象,以8%聚乙烯醇为包膜材料,改性斜发沸石为肥料载体和缓控释材料调理剂,通过添加不同沸石量制备3种复混包膜缓释肥。利用红外光谱、扫描电镜及三维荧光对3种缓释肥的进行表征。结果表明:添加改性沸石的复混包膜肥除了增加显著的沸石红外特征谱外,其余红外光谱图差异不明显,表明添加沸石对有机质(富里酸和腐殖酸)结构和化学键型并未产生明显的影响,即不影响沼渣理化性质;添加改性沸石可以使聚乙烯醇完整的覆盖在肥料表面,膜壳更加平整光滑,膜层更加致密;三维荧光光谱显示复混包膜肥Ⅰ浸出富里酸和腐殖酸浓度最大,复混包膜肥Ⅲ浓度最低,表明添加沸石有减缓肥料养分释放的效果。该研究对于利用养猪场沼渣制备包膜缓释肥有一定的参考价值。  相似文献