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931.
通过单因素试验对影响猴头菌生长的4 个主要营养因子进行研究,得出液体培养猴头菌的最佳碳源为可溶性淀粉,最佳氮源为黄豆粉,最佳无机盐为KH2PO4,最佳维生素为VB1。通过均匀设计试验对液体培养猴头菌最佳碳源、氮源、无机盐和维生素的不同配比进行研究,得出液体培养猴头菌的最佳培养基配方为4.6%可溶性淀粉、4.6%黄豆粉、0.02% KH2PO4、18 mg/100mL VB1。通过中心复合设计试验与响应面分析得出优化的猴头菌液体培养的发酵工艺为接种量11%、发酵温度25.8℃、搅拌转速137 r/min。 相似文献
932.
鉴定了从处理硝基苯废水的人工湿地中分离出的一株降解硝基苯的优势菌yc11-1,并采用中心复合设计法优化影响菌株降解硝基苯的因素来提高菌株对硝基苯的降解率.经形态学和菌株的16SrDNA序列分析,菌株yc1 1-1为蜡质芽孢杆菌(Bacillus cereus).该菌株降解硝基苯的最佳条件为初始硝基苯浓度84.84 mg/L、菌种投加量12.97%、培养温度29.4℃和pH 7.1,在此条件下理论降解率可达91.14%,实际降解率为90.58%. 相似文献
933.
Size Effect of Bending Strength of Chinese Larch Lumber 总被引:1,自引:0,他引:1
The relationship between the bending strength and the size of Chinese larch visually-graded lumber was investigated. 1,961 pieces of lumber with three different widths were divided into two groups of high visual grades and low visual grades. The ultimate bending strength was tested under test spans of 18 times test depths. The combined length and width size effects of 5th percentile of bending strength were estimated by the slope method and the parametric method. Using the slope method, the estimated effect parameters of H and L were 0.19 and 0.23 for the 5th percentile. 相似文献
934.
Preparation and applications of inorganic polymer composite flocculant poly aluminum ferric sulfate
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ZHENG Huaili CHEN Wenyuan ZHANG Zhi SUN Yongjun GUAN Qingqing LIU Liwei LU Wei ZHENG Xiaokai 《保鲜与加工》2013,(7):114-120
Industrial by-products FeSO4·7H2O is taken as raw material, concentrated nitric acid as strong oxidant and aluminum sulfate as additive to produce poly aluminum ferric sulfate(PAFS)flocculants, which is applied to the removal of organic humic acid. The study includes the reaction temperature, reaction time, Al/Fe molar ratio and basicity(OH/Fe). Infrared spectroscopy and scattering electron are used to characterize the structure of the PAFS. The results show that the product have the best coagulation effect when reaction temperature, reaction time, Al/Fe molar ratio and basicity(OH/Fe)are 60~80℃, 30~50 min, 1∶9 and 0.3 respectively. Infrared spectroscopy analysis shows the products structure and scattering electrons analysis suggests a large surface area and a strong condensed state for PAFS. The removal rate of humic acid is 94.72% when the dosage of PAFS is 3.36 mg /L, pH value is 7, rapid stirring speed is 350 rpm, fast mixing time is 2.0 min, the slow stirring speed is 40 rpm and slow stirring time is 12 min. 相似文献
935.
在四川省丹棱县退耕还林地,设置台湾桤木+多花黑麦草(AL)与台湾桤木+扁穗牛鞭草(AH)2种林草模式,以台湾桤木自然模式(AN)为对照,研究土壤有机碳含量以及土壤微生物量碳含量的季节变化.结果表明:随土层深度增加,2种林草模式与对照土壤有机碳含量和土壤微生物量碳含量均呈现下降趋势,在下降幅度上均表现为台湾桤木+扁穗牛鞭草模式较缓慢,对照模式下降最快;3种模式不同土层土壤有机碳含量从春季到冬季随季节变化均呈现“升-降-升”的变化趋势,夏季含量最高,秋季最低,但这种变化趋势在台湾桤木+扁穗牛鞭草模式下0~10和10~20 cm土层表现得并不明显;而3种模式各土层土壤微生物量碳含量则表现出与土壤有机碳季节动态相反的变化趋势,即“降-升-降”的变化趋势,夏季最低,秋季最高;2种林草模式与对照的土壤有机碳含量和土壤微生物量碳含量差异均达到极显著水平(P<0.01),其大小顺序均表现为台湾桤木+扁穗牛鞭草模式>台湾桤木+多花黑麦草模式>对照模式;台湾桤木+扁穗牛鞭草、台湾桤木+多花黑麦草模式下土壤有机碳含量分别是对照模式的1.24 ~ 1.55和1.16~ 1.30倍,土壤微生物量碳含量分别是对照模式的1.50 ~2.95和1.23 ~1.80倍. 相似文献
936.
水曲柳落叶松带状混交林结构调整对水曲柳林带土壤理化性质的影响 总被引:1,自引:0,他引:1
以黑龙江省东北林业大学帽儿山实验林场尖砬沟森林培育实验站23a生水曲柳落叶松带状混交林为研究对象,测定对落叶松林带进行不同方式结构调整后水曲柳林带土壤理化性质的变化。结果表明:不同结构调整方式,对水曲柳林带土壤物理性质未产生显著影响,对土壤部分化学性质影响显著。去边行调整后水曲柳林带土壤,上层和中层的水解N含量显著大于其它调整及对照组对应层次的含量(P<0.05),上层的有机质含量也明显大于其它调整及对照组的含量(P<0.05)。对落叶松去边行与隔株去株和品字型均匀伐相比,去边行表现出更好的改土效果。 相似文献
937.
938.
《Wood material science & engineering》2013,8(4):177-184
Abstract Mechanical properties are very important in structural uses of wood. In the case of larch wood, shear strength (SS) may be a limiting property, because the wood is brittle and it splinters easily. In this study, SS of Siberian larch (Larix sibirica) wood was studied in relation to its axial and radial location and to some other wood properties in the part of the trunk that produces logs of good carpentry quality. SS increased by 21–23% from the pith to the outer heartwood at each studied height (butt, 4.5 and 9 m), and it was at its most approximately 7% higher at the butt than at the other studied heights. The main reason for the radial increase in SS was the increase in density caused by wood maturation, but other factors also affected SS, depending on the grouping mode (combined material, radial/axial location). An exception was sapwood, for which no factors affecting SS could be identified. Thus, sapwood may behave differently from heartwood regarding use, even unexpectedly. The results suggest that mature heartwood, but not juvenile wood and sapwood, of Larix sibirica should primarily be used in products that require high SS. 相似文献
939.
A central composite design (CCD),with three variables and three levels,was used to optimize withering and fermentation processing during manufacture of Congou black tea of Sichuan.The three independent variables were withering time,fermentation time and fermentation temperature.Each factor was set by three levels.The responses were predicted by analysis of the regression equation.In the study,the models of regression equation were significant by the analysis of variance (ANOVA).The second-order response surface figures were showed that interaction term is correlated with the response.Optimal process parameters for the maximum of TF and TR formation were obtained at withering time of 12 hours,fermentation time of 2 hours,and fermentation temperature of 30C.The predictions of TF and TR formation were 0.52% and 3.98%.The results obtained in this study showed that the CCD and Response Surface Methodology (RSM) could be an effective tool to optimize the process parameters of Congou black tea manufacture. 相似文献
940.