食品微生物检验学课程教学改革研究——将实验课改为“科学小试验”的尝试

阐述了食品微生物检验学实验课教学改革的动因 ,提出了一种新的实验课教学模式 ;将实验课改为“科学小试验” ,并阐明了这种教学模式的可行性及其尝试后所收到的教学效果。

小学卫生常识课的几个小试验

对小学儿童讲解卫生常识课中的呼吸作用及有关问题时,可以作几个小试验,帮助儿童加深理解。 1.测肺活量:取一个大的塑料容器,注满水并倒置于盛有部分水的缸或盆中。在容器内插入一根管子。当儿童向管中吹气,水就排出,显示出吹入容器内的气体容积(见图一)。

从一组小试验谈碳铵深施

碳铵化肥易挥发,施用不当,损失严重。深施是减少损失的有效方法。但是,有不少农民朋友不愿深施,或深施方法不对头,碳铵利用率仅50％～70％,甚至出现伤苗死苗现象。为此,我们做了如下一组小试验: 备80厘米口径圆柱形茶杯六个,分两个模式:一是水田模式,用四个杯子,装入10厘米厚的田泥,其中两个加一层浅水,另两个不加水,四个杯子都撒入相等的一汤匙碳铵,将加水和不加水的各一杯田泥上下翻动、划平;

Data-driven methods for predicting the representative temperature of bridge cable based on limited measured data

Cable-stayed bridges have been widely used in high-speed railway infrastructure.The accurate determination of cable’s representative temperatures is vital during the intricate processes of design,construction,and maintenance of cable-stayed bridges.However,the representative temperatures of stayed cables are not specified in the existing design codes.To address this issue,this study investigates the distribution of the cable temperature and determinates its representative temperature.First,an experimental investigation,spanning over a period of one year,was carried out near the bridge site to obtain the temperature data.According to the statistical analysis of the measured data,it reveals that the temperature distribution is generally uniform along the cable cross-section without significant temperature gradient.Then,based on the limited data,the Monte Carlo,the gradient boosted regression trees(GBRT),and univariate linear regression(ULR)methods are employed to predict the cable’s representative temperature throughout the service life.These methods effectively overcome the limitations of insufficient monitoring data and accurately predict the representative temperature of the cables.However,each method has its own advantages and limitations in terms of applicability and accuracy.A comprehensive evaluation of the performance of these methods is conducted,and practical recommendations are provided for their application.The proposed methods and representative temperatures provide a good basis for the operation and maintenance of in-service long-span cable-stayed bridges.

四年级:记一次_____的小试验

写作要求：每个人都有好奇心，好奇心会驱使你去试一试。选择一次因好奇心而做的试验写下来，按照顺序把试验的经过写清楚、写具体，把自己的喜、怒、哀、乐随着试验的变化反映出来。

开展化学家庭小实验的几点体会

本文明确了家庭小实验的意义,分析了开展家庭小实验的几点限制因素,提出了开展家庭小实验的几点建议。

Study on the Introduction Experiment of 10 Wheat Cultivars

The research selected wheat cultivars, such as Aikang No. 58, Wanmai No.52 as test materials in the same ecological conditions planting, to explore relevant characters in different growth stages in order to seek the wheat cultivar suitable for introduction. The results suggested that Zhengmai No. 366 and Zhengyumai No. 9987 in test points showed high adaptability, compact plant type, earlier maturity stage and higher yield, were suitable for introduction.

活跃农村小学科技活动

农村要实行九年义务教育,还需要一段较长的时间。几年来,湘东地区农村小学毕业生升入初中的仅达60％,还有40％的小学毕业生要回乡从事农业生产劳动。这么一大批的农村建设“新兵”。

Sex Pheromone Components of the Female Black Cutworm Moth in China: Identification and Field Trials

The sex pheromone blend of a China strain of the black cutworm moth Agrotis ypsilon （Rottemberg） （Lepidoptera： Noctuidae） was investigated. Chemical analysis of pheromone gland extracts of 3-day-old females showed that individual isolated glands contained only very small amounts of pheromone. The high-resolution gas chromatography combined with mass spectrometry （GC-MS） analysis showed the presence of Cis-7-dodecenyl acetate （Z7-12：Ac, A）, Cis-9-tetradecenyl acetate （Z9-14：Ac, B）, Cis- 11-hexadecenyl acetate （Z 11 - 16 ：Ac, C）, Cis-8-dodecenyl acetate （Z8-12：Ac, E） and Cis-5-decenyl acetate （Z5-10：Ac, D） in biologically active pheromone gland extracts. An extract of one gland from a day 3 female gave the following values for the gland components： 0.245±0.098ng for Z7-12：Ac, 0.080±0.031ng for Z9-14：Ac, 0.089±0.033ng for Z11-16：Ac, 0.085±0.031ng for Z5-10：Ac, 0.105±0.065ng for Z8-12：Ac per female. The percentages of Z7-12：Ac, Z9-14：Ac, Z11-16：Ac, Z5-10：Ac and ZS-12：Ac in pheromone gland extracts from individual females were （meaniSE） 40.451±13.66, 13.176±5.279, 14.943±5.142, 14.392±6.10 and 17.225±9.792 respectively, and the percentages of Z7-12：Ac, Z9-14：Ac and Z11-16：Ac were 58.75±9.429, 18.91±7.539 and 22.34±7.209. Field trials indicated that each single component of sex pheromone was non-effective and captured no males. The lures baited with duality compound of AB （3 ： 1） had a certain attraction to males, the mean captured number was 2.6. The attraction ability of the lures baited with ternary compound of ABC （3 ： 1 ：1） to males added significantly, the mean captured number per trap was 7.40, which was 2.8 times of duality compound of AB （3 ： 1）. The contents of sex pheromone could obviously affect its capture ability to males, the mean captured number was the highest at the dosage of 200 μg.

用易拉罐制作光合成演示器

用玻璃管向叶片上用力吹气,易拉罐便高速施转,筒的侧面也就合成了与色纸完全不同的颜色。 如果在筒的侧面换上其它不同颜色的纸进行演示,便又可合成另一种颜色。

Establishment and Application of Fertilization Model for Wheat Interplanted with Cotton in Jianghan Plain

3414 field experiment （including three nutrient elements at four gradient levels, a total of 14 unrepeated incomplete treatments） was designed to study the fertilization measures for wheat interplanted with cotton in Qianjiang City, Hubei Province. Fertilizer model for wheat interplanted with cotton in Jianghan Plain was finally established, based on which the soil nutrient indices in wheat-cotton inter- planting field were screened; and optimal nitrogen, phosphorus and potassium appli- cation for wheat was put forward as 130-210 kg/hm2 N, 40-70 kg/hm2 P2O5 and 40-60 kg/hm2 K2O.

名悟

名悟亦杰名与利总是相连的。有些人重名的出发点和归宿是利，能名利双收更好，双收不了就舍名取利。不信？可做一小试验证明之：发奖金时，分成两种份额，一种２５０元，一种２４９元，看领奖者选哪一份？恐怕相当多的人会取２５０元的那份，而不在乎落个“二百五”的名声...

Total Amount Control Test of Nitrogen Fertilizer and Phosphate Fertilizer on Winter Wheat

[Objective] This study was conducted to optimize the suitable application amounts of nitrogen fertilizer and phosphate fertilizer for winter wheat.[Method] A field experiment was carried out to investigate the effects of the application amounts of nitrogen fertilizer and phosphate fertilizer on the yield of winter wheat.[Result]The quadratic simulation function between the application of nitrogen fertilizer and wheat yield was y =-0.6611x^2＋20.091 x ＋234.85,with a correlation coefficient of0.970 8,and the yield of winter wheat was the highest at the application amount of nitrogen fertilizer of 228.0 kg/hm^2.The quadratic simulation function between the application of phosphate fertilizer and wheat yield was y =-0.572 6x^2＋13.168 x ＋340.4,with a correlation coefficient of 0.921 95,and the yield of winter wheat was the highest at the application amount of phosphate fertilizer of 172.5 kg/hm^2.[Conclusion] This study provides a scientific basis for the rational application of nitrogen fertilizer and phosphate fertilizer on winter wheat.

Elastic and plastic deformation behavior analysis in small punch test for mechanical properties evaluation

In order to estimate deformation and mechanical properties of material accurately,elastic and plastic deformation behavior of small punch test was discussed in this paper.A two-dimensional finite element model was established based upon the Gurson-Tvergaard-Needleman(GTN)equation.According to the integration of load–displacement curves with different displacements,the evolution of elastic energy was obtained.The results show that the elastic energy increases quickly in the initial region and tends to be an approximate constant during the plastic bending phase.Meanwhile,an obvious change of the slope of load–displacement curve can be found in the elastic-plastic transition region.The macroscopic deformation and fracture feature were also discussed in order to verify the deformation analysis.Finally,the yield strength,tensile strength and elongation of AISI304 were obtained based on the analysis of deformation energy and percent fracture deflection.The results have a good agreement with that of conventional tensile tests,which may provide a theoretical basis of small punch analysis.

The culture and establishment of embryonic germ(EG)cell lines from Chinese mini swine

As a part of a basic research project on Xeno-transplantion. we have been engaged in the derivation of embryonic stein cell lines from Chinese mini swine. Here, we reported for the first time the establishment of two porcine EG cell lines (BPEG1 and BPEG2) from primordial germ cells of genital ridges of a 28 and a 27 d embryos respectively. Their pluripotent nature has been identified by colony morphology, marker characterization as well as by in vitro and in vivo differentiation. These porcine EG cells are potentially useful for further basic studies.

Coupled Effects of Soil Water and Nutrients on Growth and Yields of Maize Plants in a Semi-Arid Region

Interaction between soil water and nutrients plays an important role in sustainable crop management in semi-arid environments.On the basis of a field experiment conducted from 2000 to 2003,this study examined the coupled effects of irrigation and fertilizers on maize growth and yield in a semi-arid region of northeastern China.In terms of plant productivity,nitrogen fertilizer had the most significant effect followed by irrigation and phosphate levels.The combined application of nutrients and irrigation exerted a synergistic effect on the grain yield of maize plants.Regression analysis indicated that optimal levels of nitrogen and phosphate,in addition to adequate irrigation,could greatly improve the efficiency of grain production.Similarly,optimization of soil nutrient availability substantially increased water use efficiency.These suggested that for the most efficient and sustainable crop production,irrigation and nutrient management should be based on a quantitative understanding of water/nutrients interaction,particularly in semi-arid and arid regions.

Work characteristic analysis of single-rod symmetric cylinders

Hydraulic cylinders are divided into single-rod asymmetric cylinders and double-rod symmetric cylinders. The single-rod asymmetric cylinder has the advantages of small size and simple structure,but its speed characteristic is not symmetric. The double rod symmetric cylinder has the characteristic of symmetric speed,but it cannot be used in some special occasions. In this paper,one special hydraulic cylinder,a single-rod symmetric cylinder,is developed. Firstly,characters of this type of cylinder are introduced. Then,the system model is constructed by using one software which is Simulation X. Moreover,one single rod asymmetric cylinder is designed and the test rig using the symmetric valve to control single-rod symmetric or asymmetric cylinder is constructed. Both of the simulation and experimental results show that the symmetric valve control single-rod symmetric cylinder servo system is of symmetric speed characteristic,which can be used in practical occasion.

Immune functional impacts of oyster peptide-based enteral nutrition formula (OPENF) on mice:a pilot study

Oyster peptides were produced from Crassostrea hongkongensis and used as a new protein source for the preparation of an oyster peptide-based enteral nutrition formula (OPENF). Reserpine-induced malabsorption mice and cyclophosphamide-induced immunosuppression mice were used in this study. OPENF powder is light yellow green and has a protein-fat-carbohydrate ratio of 16:9:75 with good solubility in water. A pilot study investigating immune functional impacts of the OPENF on mice show that the OPENF enhanced spleen lymphocyte proliferation and the activity of natural killer (NK) cells in BALB/c mice. Furthermore, OPENF can improve intestinal absorption, increase food utilization ratio, and maintain the normal physiological function of mice. These results suggest that oyster peptides could serve as a new protein source for use in enteral nutrition formula, but more importantly, also indicate that OPENF has an immunostimulating effect in mice.