甘油超临界水气化制氢过程参数和动力学研究

为研究甘油超临界水气化制氢过程及转化动力学,采用正交试验和单因素试验,在连续式反应器中,分析不同工艺参数对甘油超临界水气化气体产物分布和气化转化效率的影响,对气体产物进行气相色谱分析。利用集总动力学研究方法,优化甘油超临界水气化转化动力学模型,增加CO₂甲烷化反应路径,探讨甘油超临界水气化过程中动力学参数和气相产物生成及消耗路径。结果表明：甘油超临界水气化制氢的最佳工况为温度600 ℃、甘油浓度0.015 mol/L、压力27 MPa和停留时间18 s,此时H₂产量为2.411 mol/mol,气化效率为76.49 %。单因素试验结果可知,较高反应温度和压力、较低原料浓度和适当延长停留时间有利于提高H₂产量和甘油气化效率。反应速率常数随着温度的升高而增加,甘油热解路径Ⅱ和中间体蒸汽重整路径Ⅰ的活化能分别高于甘油热解路径Ⅰ和中间体蒸汽重整路径Ⅱ。H₂主要通过甘油热解和水气变换反应生成,CO₂主要通过甘油热Ⅰ和水气变换反应生成,CO₂甲烷化是H₂和CO₂消耗的主要路径。中间体热解是CO和CH₄的主要生成路径,CO的主要消耗路径是水气变换反应。     

邻烯丙基苯酚对植物病原真菌抑制机理初探

用含毒介质培养法测定了邻烯丙基苯酚(银果)对番茄灰霉病菌Botrytis cinerea、苹果腐烂病菌Valsa mali和小麦纹枯病菌Rhizoctonia cerealis的影响。通过培养观察发现,邻烯丙基苯酚可抑制番茄灰霉病菌分生孢子的产生、促进灰霉病菌菌核的形成及苹果腐烂病菌子囊壳的形成。光学显微观察表明:用50μg/mL的邻烯丙基苯酚处理番茄灰霉病菌菌丝后,菌丝伸长缓慢,分支间距缩短,分生孢子形成受到抑制。电镜观察表明:经邻烯丙基苯酚处理后,番茄灰霉病菌菌丝内液泡增多,苹果腐烂病菌菌丝细胞壁增厚,小麦纹枯病菌菌丝中内质网处泡囊增多。     

超高效液相色谱-串联质谱法测定番茄中多菌灵及其主要代谢物的残留

建立了同时测定番茄中多菌灵及其主要代谢物(2-氨基苯并咪唑和苯并咪唑)的超高效液相色谱-串联质谱(UPLC-MS/MS)分析方法。番茄样品用乙腈超声提取,经浓缩后用初始流动相稀释并定容,过0.22 μm滤膜后进行UPLC-MS/MS分析。采用多反应监测(MRM)模式测定,外标法定量。结果表明:在添加水平为0.05~5 mg/kg下,多菌灵及其主要代谢物的平均回收率为70.5％~104.9％,相对标准偏差为2.6％~9.5%。方法的检出限(LOD)为0.16~4.73 μg/kg,定量限(LOQ)为0.29~4.99 μg/kg。     

Distribution of latent bovine herpesvirus 2 DNA in tissues of experimentally infected sheep

The biology of latent infection by bovine herpesvirus 2 (BoHV-2), the agent of mammillitis in cows, remains largely unknown. We herein report attempts to reactivate the latent infection and investigated the sites of BoHV-2 latency in experimentally infected sheep. Ewes inoculated with BoHV-2 in the udder’s skin shed virus for up to five days, developed mammillitis and seroconverted. However, attempts to reactivate latent infection by dexamethasone administration at day 40 pi failed. Nevertheless, viral DNA - and not infectious virus - was detected by PCR in several nerve ganglia and/or regional lymph nodes (LNs) of all animals at day 40 post-reactivation. Likewise, lambs previously inoculated with BoHV-2 in the nose harbored latent viral DNA in trigeminal ganglia, tonsils and regional LNs. These results demonstrate that BoHV-2 establishes latent infection in nerve ganglia and in regional lymphoid tissues, yet virus reactivation is not easily achieved by standard protocols used.     

Short term soil priming effects and the mineralisation of biochar following its incorporation to soils of different pH

The aim of this work was to determine the magnitude of the priming effect, i.e. short-term changes in the rate (negative or positive) of mineralisation of native soil organic carbon (C), following addition of biochars. The biochars were made from Miscanthus giganteus, a C4 plant, naturally enriched with ¹³C. The biochars were produced at 350 °C (biochar350) and 700 °C (biochar700) and applied with and without ryegrass as a substrate to a clay-loam soil at pH 3.7 and 7.6. A secondary aim was to determine the effect of ryegrass addition on the mineralisation of the two biochars.After 87 days, biochar350 addition caused priming effects equivalent to 250 and 319 μg CO₂-C g⁻¹ soil, in the low and high pH soil, respectively. The largest priming effects occurred at the start of the incubations. The size of the priming effect was decreased at higher biochar pyrolysis temperatures, which may be a way of controlling priming effects following biochar incorporation to soil, if desired. The priming effect was probably induced by the water soluble components of the biochar. At 87 days of incubation, 0.14% and 0.18% of biochar700 and 0.61% and 0.84% of biochar350 were mineralized in the low and high pH soil, respectively. Ryegrass addition gave an increased biochar350 mineralisation of 33% and 40%, and increased biochar700 at 137% and 70%, in the low and high pH soils, respectively. Certainly, on the basis of our results, if biochar is used to sequester carbon a priming effect may occur, increasing CO₂-C evolved from soil and decreasing soil organic C. However, this will be more than compensated for by the increased soil C caused by biochar incorporation. A similar conclusion holds for accelerated mineralisation of biochar due to incorporation of fresh labile substrates. We consider that our results are the first to unequivocally demonstrate the initiation, progress and termination of a true positive priming effect by biochar on native soil organic C.     

苯并噻二唑甲酸三氟乙酯诱导仙客来抗枯萎病的研究

为了明确新型化合物苯并噻二唑甲酸三氟乙酯对土传病害的诱导抗病作用,本文研究了该化合物诱导仙客来对枯萎病的抗病效果。通过叶面喷施苯并噻二唑甲酸三氟乙酯可诱导仙客来对枯萎病的抗病效果,在仙客来移栽缓苗后7d叶面喷施该化合物,不同浓度对枯萎病的抗病效果不同,其中100mg.L-1的处理,在诱导后25、30和35d的抗病效果分别为82.90%、58.59%和64.17%;在仙客来成株枯萎病发病初期用该化合物诱导,抗病效果仍可达63.91%,显著高于噁霉灵处理（47.63%）。该研究将为寻求通过叶面喷雾施药防治园艺作物土传病害的新途径起到参考作用。     

滴灌条件下核桃园土壤水分动态变化的数值模拟研究

为探究滴灌条件下核桃根系对土壤含水量的影响,试验以8 a生核桃树为研究对象,使用分层分段挖掘法分析核桃根系的空间形态分布,通过构建HYDRUS-2D模型,对有根系吸水下的土壤水分变化进行求解,并利用实测点数据校验2D模型的可用性。经过实际计算与理论分析,得出如下结论:在垂直二维剖面中,水平距树0~30 cm、垂直40~60 cm土层的细根根长密度分布最大,为1 618.216 m·m~(-3)。对比实测数据与模拟数据,结果显示RMSE均小于0.0186 cm~3·cm~(-3),ME绝对值小于0.0108 cm~3·cm~(-3),证明数值模拟效果较好,HYDRUS模型可应用于实际试验研究。将根系模块纳入模型模拟,并比照单独水流模块作用,结果显示根系对土壤含水量产生影响,使体积含水率曲线整体低于单独水作用下的含水率曲线,且两者关系差异性显著。模拟核桃生育前期土壤含水量变化,结果表明灌水后6 d至7 d内,土壤含水量存在明显减小现象,故可将生育前期灌水周期设定为6 d或7 d。     

不同品种断奶仔猪肠道发育的差异及与血清胰高血糖素样肽-2的关系

为考察不同品种断奶仔猪小肠发育的差异及肠绒毛高度与血清GLP-2的关系,本试验分别测定了不同品种仔猪24、26d和30d时的血清GLP-2浓度及30d时肠道发育参数,并分析了回肠绒毛高度与GLP-2的关系。结果表明:大×太猪的小肠长(相对长)、小肠重(相对重)显著高于长白猪(P0.05),小肠重显著高于太湖猪(P0.05),而太湖猪小肠相对重显著高于长白猪(P0.05),小肠相对长极显著高于长白猪(P0.01);大×太猪和长白猪的回肠肠壁厚度、绒毛高度和隐窝深度显著高于太湖猪(P0.05);30d时,大×太猪血清GLP-2水平最高,且极显著高于长白猪和太湖猪(P0.01),3种猪回肠绒毛高度与血清GLP-2极显著相关(P0.01)。表明30d时的大×太猪肠道发育优于太湖猪和长白猪,不同品种断奶仔猪的小肠绒毛高度与血清GLP-2水平高度相关。     

基于MODIS数据的2001—2016年内蒙古积雪分布及其变化趋势

积雪融水是干旱区重要的水资源之一,积雪分布变化的监测对区域雪冰资源的合理利用及灾害防治至关重要。基于内蒙古地区2001-2016年MOD10A2积雪数据对研究区进行分带提取,分析不同海拔高度积雪年内年际变化特征,结合气温和降水气象因素,分析其分布变化原因。研究表明:积雪面积、积雪覆盖率年内分布呈单峰形,10个海拔带的积雪期为9月到次年5月,峰值出现在冬季,积雪覆盖率增减的临界高度在952~1 114 m;不同高程带的积雪面积在春季、夏季、秋季整体上呈现出"增加-减少-增加-减少"的年际变化规律,冬季整体上表现出"减少-增加-减少"的变化规律;积雪面积受降水量和气温相互的影响,其中海拔高度可能起到间接作用。内蒙古地区春季、冬季积雪覆盖率均与冬季降水量呈显著正相关,各季节积雪覆盖率基本与温度呈负相关关系。