The chloride mask in COD determination of pickled mustard wastewater with high salt

Chlorides in the wastewater with high salt seriously interrupts the determination of chemical oxygen demand(COD). Therefore, chloride mask in wastewater has been an important and difficult issue in recent years. In the present work, experiment design is used for more accurate and precise COD determination method of pickled mustard wastewater. Two methods for masking chloride are adopted: HgSO4 masking method and AgNO3 masking method. After masking chloride, use the traditional reflux digestion method to test COD in the experimental sample. The results show that when the ratio of HgSO4 to Cl - is 40, the chloride mask results in a minimum error of 1.43%, and the minimum error is 0.21% when AgNO3 is used. Obviously, AgNO3 masking method is superior to HgSO4 masking method. However, when these two methods are used in pickled mustard wastewater, there is a COD value difference of 20 mg/L and HgSO4 masking method is more accurate. By considering the characteristics of the two methods above, a combined method is proposed, which AgNO3 is added equivalently according to the concentration of Cl - first, and then a few amounts of HgSO4 are added to prevent the free Cl - in wastewater. The facts show that combined method is more reliable.     

The effects of allowance and frequency of allocation of autumn-saved pasture, when offered to spring lambing ewes in mid pregnancy, on ewe and lamb performance and subsequent herbage yield

The effects of (i) frequency of herbage allocation and (ii) herbage allowance on ewe and subsequent lamb performance, when autumn-saved (extended grazed, deferred grazed) pasture is grazed (between 28 Nov and 30 Jan) by spring lambing ewes during mid gestation, were studied in Experiment 1. This involved 72 crossbred ewes from days 41 to 104 of gestation allocated to one of four treatments; two herbage dry matter (DM) allowances (1.0 and 1.8 kg per ewe) by two frequencies of herbage allocation (daily or twice weekly). From day 105 of gestation to parturition all ewes were housed and offered grass silage (ad libitum) plus a total of 19 kg concentrate. Increasing herbage allowance improved ewe body condition score (P < 0.01) and live weight (P < 0.01) at the end of deferred grazing, and tended to increase herbage intake (P = 0.08) during deferred grazing. Reducing the frequency of herbage allocation increased lamb birth weight (P < 0.05). Otherwise frequency of herbage allocation did not alter (P > 0.05) forage intake or utilization, or ewe or subsequent lamb performance. In Experiment 2, the effects of herbage allowance (1.0 or 1.8 kg DM per ewe), frequency of allocation (daily, twice weekly) and grazing date (28 Nov. to 4 Dec., 12 to 18 Dec., 2 to 8 Jan. and 23 to 29 Jan.) during deferred grazing on herbage yield and composition at four subsequent harvest dates (4, 18 and 25 Apr., and 25 May) were evaluated in a split-plot design consisting of 128 plots. Delaying grazing date reduced herbage yield (P < 0.05) and the concentrations of neutral detergent fibre (NDF; P < 0.01) and acid detergent fibre (ADF; P < 0.01). Delaying harvest date increased herbage yield (P < 0.001) and reduced (P < 0.001) the concentrations of NDF, ADF and metabolisable energy. Increasing herbage allowance at grazing increased (P < 0.05) subsequent herbage yield. Frequency of herbage allocation during deferred grazing did not affect (P > 0.05) subsequent herbage yield. There was a significant interaction (P < 0.001) between grazing date and harvest date for herbage yield. It is concluded that to maximise stock carrying capacity and reduce labour requirement a herbage DM allowance of 1 kg per ewe per day, allocated twice weekly, is sufficient for ewes on deferred grazed pasture in mid pregnancy.     

氮肥对油菜在不同土壤中吸收积累Cd的影响

以三种不同程度Cd污染土壤为材料,通过盆栽试验研究NH₄Cl和（NH₄）₂SO₄两种氮肥对土壤Cd有效性及油菜吸收、转运Cd的影响,评价油菜对Cd的生物累积量,以期为油菜修复Cd污染土壤的优化施肥措施提供理论支撑。结果表明：施加NH₄Cl和（NH₄）₂SO₄均显著降低了土壤的pH,（NH₄）₂SO₄处理土壤pH低于施加NH₄Cl处理的土壤,施肥处理下生长期非根际土pH低于根际土,成熟期非根际土pH高于根际土。施加（NH₄）₂SO₄和NH₄Cl均使土壤中有效态Cd含量增加。（NH₄）₂SO₄处理有效态Cd的浓度高于NH₄Cl处理。油菜成熟期土壤中有效态Cd的浓度低于生长期,生长期和成熟期整体表现出根际土中Cd的总量高于非根际土。施加（NH₄）₂SO₄和NH₄Cl均增加油菜各部位Cd的含量,提高油菜的富集系数和转运系数,油菜从根到叶对Cd的转运系数最高。研究表明油菜作为Cd污染土壤的修复植物有一定安全保障。     

氯化亚铜催化的月桂烯氢氯化反应的研究(Ⅲ)——烯丙基型氯化物的酯化反应

研究月桂烯氢氯化反应产物中里哪基氯、香叶基氯和橙花基氯３种烯丙型氯化物与醋酸钠的酯化反应。重点考察了催化剂、反应温度和氯化物组成对酯化反应产物分布的影响。结果表明：（１）在氯化亚铜催化剂存在下，３种烯丙基型氯化物与醋酸钠在醋酸溶剂中均可转化成醋酸里哪酯，酯化反应选择性达９６％以上；（２）在三乙胺催化剂存在下，３种烯丙基型氯化物与醋酸钠反应可转化成相应的醋酸酯，但里哪基氯酯转化生成醋酸里哪酯的选择性明显低于香叶基氯和橙花基氯，且伴随有消除副产物生成；（３）低温有利于醋酸里哪酯的生成，温度升高有利于醋酸里哪酯向醋酸香叶基酯和醋酸橙花酯的生成；在优化反应条件下，醋酸里哪酯的选择性达９６．５％。     

施氮水平对无芒雀麦产量和营养成分含量的影响

无芒雀麦草地增旋N0 、N6 0 、N90 和N12 0 四个处理 ,重复 3次 ,经 3年的观测 ,其结果表明 ,在每公顷施氮 60— 1 2 0 的范围内 ,无芒雀麦的干物质产量随施氮水平的提高而增加 ,施氮水平较高时 (N12 0 )、无芒雀麦在施肥后连续两年内增产效果显著。粗蛋白质含量亦随施氮水平的提高而提高 ,无氮浸出物含量变化正好相反 ,粗脂肪含量有随施氮水平提高而增加的趋势 ,但增加的量甚小 ,对家畜营养影响不大。     

新疆放牧绵羊的限制性矿物质元素调查

通过新疆5个羊场矿物质元素营养的研究，以了解新疆全年草场有关矿物元素的变化情况，缺乏程度及缺乏时间。研究表明：5个羊场中牧草含P量在秋草场至冬草场均表现缺乏。含Na量在塔城种羊场一年四季草场均缺乏，在阿勒泰二牧场冬、春、夏草场Na出现明显缺乏，而在秋草场又明显超出需要量；在巩乃斯种羊场春、夏草场明显缺乏，冬、牧草场又明显超量。5个羊场牧草含Se、Zn量的测定值明显低于需要量。而含Fe量在5个羊场中都不同程度地超过最高限量。牧草中元素Fe与Mn之间存在措抗作用；Mo、Cu比例少于1：4，绵羊体内仍表现缺Cu症。通过全面分析对比，初步确定在新疆5个种羊场天然草场上放牧的羊群，存在着P、Na、Zn、Mn、Se和Cu6种限制性矿物元素季节性营养紊乱现象。     

Cl对烤烟光合作用的影响

采用全生育期水培试验研究 Ｃｌ对烤烟光合作用的影响．结果表明,适量施 Ｃｌ可促进烟叶叶绿素合成,提高净光合速率和光饱和点,降低光补偿点,缓和“午休”现象,从而提高烤烟整体的光合效率,提高烟叶产量．缺 Ｃｌ和过量施 Ｃｌ都显著影响烤烟的光合作用,但表现出不同的规律性．     

气流冲击式转筒干燥机设计与试验

设计了一种气流冲击式转筒干燥机,与常规式转筒干燥机相比,具有传热系数高、物料受热均匀、节约能源、单位体积装载量多等特点。干燥机采用保温隔热、热空气循环利用以及换气除湿等方法,工作时可根据不同物料的特性和产品要求调整热风温度、相对湿度、风速、转筒转速等工艺参数以及分支喷管直径、高度、倾角等结构参数。以牧草种子(披碱草种子)和胡萝卜丁为试验物料对气流冲击式转筒干燥机进行了性能试验,干燥后的披碱草种子可达到国家Ⅰ级种子标准,脱水胡萝卜丁复水后与原物料L、a、b色差ΔE仅为5.95。     

种子引发提高草类植物抗旱性的表现及机理

干旱是限制植物生长的重要因素之一。种子引发是通过调控种子吸水状态,激活种子生理代谢过程,使种子质量与植物抗逆能力得到提升的一种种子处理方式。种子引发技术能显著提升草类植物的发芽率、幼苗整齐度和田间表现等,并在改善草类植物抗旱性方面有广阔的应用潜力。本文论述了种子引发常规方法和新技术、总结了其在草类植物抗旱中的研究,从形态变化、生理生化响应和分子调控三个层面明确了种子引发技术提高抗旱性的内在机制,并对种子引发技术面临的问题及未来发展方向进行展望。     

不同放牧率对草原牧草再生性能和地上净初级生产力的影响

在生长季研究不同放牧率对草原牧草再生性能和地上净初级生产力的影响。结果表明,随着放牧率的增大,地上现存量呈线性下降,但地上净初级生产力(地上现存量＋家畜采食量)以2.67只羊/hm²处理最大,即存在超补偿性生长。地上最大现存量和最大净初级生产力出现的日期随着放牧率的增大有提前的趋势,二者随着放牧年限的延长均有较大幅度的下降。但降水可以缓和或加剧此变化的趋势。在冷蒿小禾草退化草原上,1.33和2.67只羊/hm²始牧时期为5月中下旬为宜,而重度放牧宜在6月上、中旬;重牧或过度放牧可降低牧草早期的再生能力,但可加快后期的再生速度,即后期牧草补偿性生长较明显。