DATA COMPRESSION WITH HASH CODES     

Tan Qiangmin 《保鲜与加工》1990,(1):119-126

In many database applications, data have to be compressed before they can be stored. Data compression techniques with less overhead and better space saving are expected. This paper gives a data compression technique by which the size of a file may be reduced through substituting codes for its field values. The codes are the corresponding locations of the values in the hash table that is comprised of all the values of the field.The compression is effective for many applications, and the cost of the coding/decoding is equal to that of one access to the hash table. The implementation of the technique as a compression tool in DBMS for date storage and the algorithms of the coding/decoding are discussed.  相似文献   

极早熟玉米制种中应注意的几个问题     

王男  刘兴焱  谭福忠 《中国种业》2005,(11):42

黑龙江省北部北纬48.以北地区属寒温带湿润、半湿润气候,无霜期110～130d,秋霜早,干旱少雨,全年降水量400～800mm,其中60%集中在7-9月份.应用品种积温一般在1800～2200℃,品种熟期一般为80～100d,该地区年有效积温1900～2400℃,习惯上将适应这一地区生态条件而栽培种植的玉米称为极早熟玉米.目前生产上应用的极早熟玉米品种主要有克单8号、克单9号、冀承单3、海玉5号、卡皮托尔等.  相似文献   

水培甜瓜对营养液及主要矿质元素的吸收特性   总被引：3，自引：0，他引：3  

谭学文  刘增鑫 《华北农学报》1996,11(3):101-105

在ＤＦＴ栽培条件下，从定植到收获，甜瓜日平均吸收营养液０．４１Ｌ，定果后１０天内出现吸收峰值（１．１３Ｌ／株），收获前仍维持较高水平。不同生长时期内，甜瓜对钾、钙、镁、磷的吸收变化与甜瓜对营养液的吸收变化基本相似，营养生长时期，吸收量较少，授粉后吸收量急剧增加，在定果后１０天内出现吸收峰值，此后急剧减少，但甜瓜对钾的吸收峰值超前一周出现。根据甜瓜对主要大量元素的实际吸收浓度，可以推算甜瓜合适的营养液配方  相似文献   

甘薯品种抗旱适应性的数量分析   总被引：14，自引：2，他引：14  

谈锋  张启堂 《作物学报》1991,17(5):394-398

抗旱适应性的定量描述是甘薯品种抗旱性改良的基础工作。目前在甘薯品种抗旱形态指标筛选和抗旱适应性的生理机理方面只有少量研究,尚无抗旱适应性定量描述的报道。本文在测定六个甘薯品种十项抗旱形态生理指标的基础上,运用模糊数学关于隶属函数的方法对甘薯品种抗旱适应性的定量描述作了初步探索。  相似文献   

诱导百合鳞片芽的影响因子研究   总被引：4，自引：0，他引：4  

李黛  谈锋 《种子》2004,23(11):18-20

采用正交试验的方法,在MS固体培养基上研究鳞片位置和不同浓度蔗糖、6-BA(6-苄基腺嘌呤)及NAA(α-奈乙酸)对诱导淡黄花百合不定芽的影响.结果表明:最佳外植体为中层鳞片,最佳培养基为MS 0.5mg/L 6-BA 0.5mg/L～1 mg/L NAA 3%～5%蔗糖.  相似文献   

新形势下兔球虫病的防控措施     

蔡丽莹  李晓斌  刘园  刘丽丹  林瑞庆  翁亚彪  谭志坚 《广东畜牧兽医科技》2022,47(1):34-38

兔球虫病是养兔业常见及危害最严重的一种寄生虫病,给养兔业造成巨大的经济损失,幼兔感染严重者甚至引起死亡,成年兔一般呈耐性感染.目前兔球虫病的防控主要以药物防控为主,不合理的抗球虫药物使用容易导致虫株耐药性、药物残留和毒性等问题的出现.随着减抗、替抗和禁抗养殖的持续推进,本文介绍可行的化学药物、中药、微生态制剂和饲养管理...  相似文献   

Modeling the relationship between the main emulsion components and stability, viscosity, fluid behavior, zeta-potential, and electrophoretic mobility of orange beverage emulsion using response surface methodology     

Mirhosseini H  Tan CP  Hamid NS  Yusof S 《Journal of agricultural and food chemistry》2007,55(19):7659-7666

The possible relationships between the main emulsion components (namely, Arabic gum, xanthan gum, and orange oil) and the physicochemical properties of orange beverage emulsion were evaluated by using response surface methodology. The physicochemical emulsion property variables considered as response variables were emulsion stability, viscosity, fluid behavior, zeta-potential, and electrophoretic mobility. The independent variables had the most and least significant ( p < 0.05) effect on viscosity and zeta-potential, respectively. The quadratic effect of orange oil and Arabic gum, the interaction effect of Arabic gum and xanthan gum, and the main effect of Arabic gum were the most significant ( p < 0.05) effects on turbidity loss rate, viscosity, viscosity ratio, and mobility, respectively. The main effect of Arabic gum was found to be significant ( p < 0.05) in all response variables except for turbidity loss rate. The nonlinear regression equations were significantly ( p < 0.05) fitted for all response variables with high R (2) values (>0.86), which had no indication of lack of fit. The results indicated that a combined level of 10.78% (w/w) Arabic gum, 0.56% (w/w) xanthan gum, and 15.27% (w/w) orange oil was predicted to provide the overall optimum region in terms of physicochemical properties studied. No significant ( p > 0.05) difference between the experimental and the predicted values confirmed the adequacy of response surface equations.  相似文献   

Tissue-specific effect of dietary cysteamine on expression of adiponectin receptors in rats     

Xu J  Shao W  Chi H  Tan Y  Zhao R 《Journal of agricultural and food chemistry》2007,55(19):7968-7973

  相似文献   

干旱区受损植被生态恢复需水量——以新疆哈巴河县平原区为例     

谭翻  杨鹏年  王翠  李志鹏  高凡  徐燕  吴强 《水土保持通报》2023,43(1):244-252

[目的]分析干旱区受损植被恢复过程中生态需水量,为生态恢复不同阶段所需水资源量及水资源优化配置提供科学依据。[方法]基于1990,2000,2010,2015,2020年Landsat系列影像,采用遥感技术,结合改进的彭曼公式法,对新疆哈巴河县平原区植被耗水量时空演变特征及生态恢复需水量进行了定量研究。[结果](1)1990—2020年天然植被平均耗水量为7.55×10⁸ m³,以3.60×10⁷ m³/5 a的速率减小,与之对应的是天然植被面积以17.36 km²/a的速率减小,植被覆盖度从高植被覆盖度向中植被覆盖度转化,生态受损严重。(2)区域内植被耗水量时空分布均存在较大差异：空间上高值主要分布于哈巴河流域,别列则克河流域植被耗水量整体偏低;时间上年际变化以2000年植被耗水量为最高,年内植被耗水量则主要集中在生长中期。(3)绿洲区生态恢复需水量如下：维持现状(2020年)生态需水量为4.62×10⁸ m³,恢复到1990—20...  相似文献   

Rhodococcus equi in the soil environment of horses in Inner Mongolia, China     

Takai S  Zhuang D  Huo XW  Madarame H  Gao MH  Tan ZT  Gao SC  Yan LJ  Guo CM  Zhou XF  Hatori F  Sasaki Y  Kakuda T  Tsubaki S 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2006,68(7):739-742

Little is known about the distribution of Rhodococcus equi in the soil environment of native horses in China. One hundred and eight soil samples were collected from native-horse farms in the Hulun Beier grasslands of eastern Mongolia, the Xilin Goler grasslands of southern Mongolia, and Tongliao City in Inner Mongolia, China. The isolation rates of R. equi from soil samples from the Hulun Beier and Xilin Goler grasslands ranged from 25.9% to 30.0%. In contrast, isolation rates from soil samples from Tongliao City were as high as 82.3% and the mean number of R. equi in soil samples from Tongliao City was 10 times more than those of samples from the grasslands. The 488 isolates were examined using PCR for the presence of genes that encode virulence-associated 15-17 kDa antigen protein (VapA) and the 20 kDa antigen protein (VapB). All isolates were negative for virulence-associated proteins. Plasmid profiles of these avirulent isolates showed that cryptic plasmids of various sizes were present with an incidence of 13.3% to 21.5%. The results of the present study contrast with those of our recent study (J. Vet. Med. Sci. 67:611-613, 2005), in which we reported that R. equi was absent from Mongolian horses in Ulaanbaatar, Mongolia. It is suggested that the difference between the results of these two studies is due to the mobile pasturing system in Mongolia and nonmobile pasturing system in Inner Mongolia.  相似文献