Passage of sediment through flumes and over weirs

This paper reports on laboratory research on the sediment passagecapability through long-throated flumes and broad-crested weirs withwhich the Froude number in the approach channel does not exceed 0.6over a distance of about 20 times the water depth upstream of thestructure. Design rules are given for any combination of flume or weirin combination with any channel.     

Use of the BCR three-step sequential extraction procedure for the study of the partitioning of Cd, Pb and Zn in various soil samples

A slightly modified three-step sequential extraction procedure proposed by the Community Bureau of Reference (BCR) for analysis of sediments was successfully applied to soil samples. Contaminated soil samples from the lead and zinc mining area in the Mezica valley (Slovenia) and natural soils from a non-industrial area were analysed. The total concentrations of Cd, Pb and Zn and their concentrations in fractions after extraction were determined by flame or electrothermal atomic absorption spectrometry (FAAS, ETAAS). Total metal concentrations in natural soils ranged from 0.3 to 2.6 mg kg^-1 for Cd, from 20 to 45 mg kg^-1 for Pb and from 70 to 140 mg kg^-1 for Zn, while these concentrations ranged from 0.5 to 35 mg kg^-1 for Cd, from 200 to 10000 mg kg^-1 for Pb and from 140 to 1500 mg kg^-1 for Zn in soils from contaminated areas. The results of the partitioning study applying the slightly modified BCR three-step extraction procedure indicate that Cd, Pb and Zn in natural soils prevails mostly in sparingly soluble fractions. Cd in natural soils is bound mainly to Fe and Mn oxides and hydroxides, Pb to organic matter, sulphides and silicates, while Zn is predominantly bound to silicates. In contaminated soils, Cd, Pb and Zn are distributed between the easily and sparingly soluble fractions. Due to the high total Cd, Pb and Zn concentrations in contaminated soil close to the smelter, ! and their high proportions in the easily soluble fraction (80% of Cd, 50% of Pb and 70% of Zn), the soil around smelters represents an environmental hazard.     

Relationship between corn yield and chemical composition of the ear leaf measured with different regression models

Abstract

Corn yields and leaf samples were obtained from experimental plots receiving varying rates of N, P and K. Yields were regressed on leaf levels of N, P, K, Ca, Mg, B, Cu, Fe, Mn and Zn as independent variables. Various polynomial regressions were fitted to the yields and “goodness of fit”; of particular mathematical models was used as a basis for evaluating particular biological and statistical concepts.

It was found that no regression, where chemical elements were used as ratios, fit the observations as well as a quadratic polynomial or its square root transformation. This suggests that within the set of data used, emphasis on particular cation or anion ratios does not necessarily result in the “best”; explanation of variation in yield.

“Classical”; growth equations were fitted to corn yields, but were not as precise in predicting yields as the polynomials. A modified stagewise regression procedure was used for fitting one mathematical model, but results were less satisfactory than those obtained with usual least squares procedures.     

响应面法优化发酵鹿肉干工艺及其货架期预测

为改善发酵鹿肉干的品质,对鹿肉干进行发酵工艺优化,并建立货架期预测模型。采用单因素和响应面试验设计,以剪切力为评价指标,结合感官评价,进行鹿肉干工艺优化,研究不同贮藏温度下发酵鹿肉干的挥发性盐基氮(TVB-N)和硫代巴比妥酸值(TBARS)的变化,利用阿伦尼乌斯方程建立货架期预测模型。结果表明,发酵鹿肉干的最佳工艺为戊糖片球菌:木糖葡萄球菌:植物乳杆菌体积比2:2:1,发酵剂接种量5%,发酵温度30 ℃,发酵时间45 h。TVB-N和TBARS的活化能Ea分别为36.42、24.95 kJ·mol^-1,指前因子k₀分别为2.17×10⁶、2.44×10⁴。验证结果表明,以TVB-N和TBARS为指标可以对发酵鹿肉干货架期进行准确预测。     

西宁市不同功能城区土壤重金属镉含量及形态研究

采取Tessier连续提取法,对西宁市不同功能城区土壤重金属镉的含量及形态分布进行研究。结果表明：西宁市各功能区土壤的全镉含量是全国土壤几何平均值的7.4-11.1倍,重金属镉污染比较严重;不同功能区中,不同形态的Cd分布有较大的差异;Cd以残渣态为主;矿冶区和开发区Cd的金属活性相对较强,具有一定的生物有效性和潜在的生态危害性。     

北安地区水稻叶龄模式化栽培技术初探

通过对北安地区两种水稻主栽品种叶龄进程的跟踪调查,总结出北安地区水稻叶龄与水稻生育进程的关系,掌握了适合本地区的正确的水稻叶龄诊断技术。研究表明,这项技术对水稻安全抽穗、提高产量具有十分重要的指导意义,从而为北安地区水稻叶龄模式化促控栽培技术模式的探索提供了科学依据。     

雪莲果的护色及其糖制工艺优化

[目的]优化雪莲果的护色硬化及糖制工艺。[方法]以贮藏6个月的雪莲果为原料,采用无硫护色硬化技术,通过正交试验优化雪莲果的护色硬化液配方及糖制工艺。[结果]雪莲果的护色硬化液最优配方为：氯化钠0.8%、柠檬酸1.0%、氯化钙1.0%、亚硫酸钠0.1%,烫漂4 min后的雪莲果果坯经此配方的护色硬化液处理后,色泽好,质地脆。雪莲果的糖制工艺条件为：经上述护色硬化处理后的雪莲果在蔗糖浓度为30%,柠檬酸用量为1.0%,羧甲基纤维素钠0.8%,浸糖温度为50℃,浸糖2 h。按此工艺制作的雪莲果脯色泽金黄,透明度好,表面光滑,脯体饱满,软硬适度,酸甜可口,具有雪莲果的清香味。其中蔗糖浓度、浸糖温度及浸糖时间是雪莲果脯糖制过程中的关键控制因子。[结论]该研究为雪莲果深加工过程中的护色硬化处理及开发利用提供了理论基础。     

中法民事审前准备程序比较

我国的民事审前准备程序存在着诸多问题,改革完善势在必行。中法两国民事审前准备程序在法律框架、实践层面上有同亦有异。改革和完善我国目前的审前准备程序不能冒进,应在现有法律制度的基础上,借鉴与我国法律文化相似国家的经验,根据我国的国情进行。     

柄海鞘神经复合体的显微观察

采用甲苯胺蓝染色和Golgi镀银法对柄海鞘神经复合体的结构进行显微观察,并通过免疫组织化学方法对甲硫氨酸脑啡肽在神经复合体中的分布进行了研究。①甲苯胺蓝染色法显示,神经复合体由神经节、神经腺和疏松结缔组织组成;神经节分为皮质部、髓质部和过渡带;神经腺位于神经节背侧面,由腺小叶组成;神经细胞呈深蓝色,神经纤维呈浅蓝色,与背景反差较大。Golgi镀银法显示的结果不理想,神经细胞和神经纤维着色不明显。②免疫组化结果显示,M-ENK在神经复合体中分布广泛,神经细胞、神经纤维及上皮细胞均有Met-ENK阳性反应。     

宫颈上皮内瘤样病变的诊断及其治疗方式的选择

目的探讨宫颈上皮内瘤样病变（CIN）的诊断方法及其治疗方式的选择。方法回顾性分析我院自2004年1月至2006年12月各类CIN患者122例进行的阴道镜下活检及宫颈电刀环切术（Leep）的病理诊断。结果CIN—Ⅰ术后病理诊断没有升级病例,与术前宫颈活检符合率为83．3％;CIN—Ⅱ术后病理诊断有8例升级为CIN—Ⅲ,10例降级为CIN—Ⅰ,2例降为慢性宫颈炎;与术前宫颈活检诊断符合率为65．5％。CIN—Ⅲ术后病理诊断有1例升级为原位癌,3例降级为CIN-Ⅱ,与术前宫颈活检诊断符合率为79．2％;原位癌术后病理诊断有2例升级为浸润癌,2例降级为CIN-Ⅲ,与术前宫颈活检诊断符合率为60％。结论CIN治疗应根据患者的年龄,是否有生育要求,阴道镜下宫颈活检的分级,恰当而合理地选择手术方式。