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1.
以野生蕨菜产地中d<0.25mm的土壤微团聚体质量分数为依变量,以有机质、全氮、全磷、全钾、速效氮、速效磷、速效钾为自变量进行了通径分析,结果表明:对d<0.25mm土壤微团聚体质量分数有正效应的主要因子为速效磷,其次为速效氮和有机质;有负效应的主要因子为全磷,其次全钾.  相似文献   

2.
探讨了生料酿酒的最佳条件,以原料出酒率为评价指标,通过正交试验的方法得出生料酿酒出酒率最高时的工艺条件是:pH值为5、发酵时间为10d、曲料比为1.0%、发酵温度为32℃、水料比为300%。  相似文献   

3.
利用能源甜菜进行乙醇发酵已引起人们重视.由于发酵温度对乙醇发酵效果影响较大,为了探讨不同菌种对发酵温度高低的适应性,筛选适应高温发酵的优良菌株,本研究首先利用温度单因素筛选出耐高温菌种HADY,45℃时乙醇转化率仍达81.68%;菌种ADY在31℃时乙醇转化率最高.然后利用Plackett-Burman设计和响应面分析法(RMS)从与发酵相关的9个因素:底物质量浓度、料液比、加菌量、营养盐添加量、加磷量、pH值、转速、发酵温度和发酵时间中依次筛选出底物质浓度、发酵温度和加磷量3个主要影响因素.优化后的工艺参数为:底物质量浓度为12%、料液质量比1:1、加菌量15%、营养盐0.5、加磷量0.9%、pH值5.0、转速130r/min、发酵温度37℃和发酵时间44h.此条件下的乙醇转化率为89.43%.  相似文献   

4.
采用二步发酵法,研究黏质沙雷氏菌的产几丁质酶发酵条件.在二步发酵产酶的过程中,通过单因素法优化得到二步发酵培养基中最适碳源、氮源的质量分数和菌龄,同时选取发酵时间、初始pH值、接种菌体量和装液量4个因子进行正交试验.最终得到的最优条件:胶体几丁质质量分数为0.8%,酵母粉质量分数为1.0%,菌龄为12 h,发酵时间为7...  相似文献   

5.
以玉米胚为原料,对玉米胚谷胱甘肽的提取方法进行研究.采用水提法提取玉米胚中还原型谷胱甘肽.并采用正交试验确定了最佳提取工艺条件:料液比为1:15,提取温度为90℃,提取液pH值为4,提取时间为15min.玉米胚中还原型谷胱甘肽质量分数为0.119%.  相似文献   

6.
采用能有效保护抗病毒活性基团的直接水提法提取异枝麒麟菜活性硫酸多糖,通过正交试验研究了影响多糖得率的工艺参数:KCl质量分数、温度、时间、料液比;通过均匀试验研究了其中影响最大的因素的最佳水平.结果表明,温度和KCl质量分数为多糖得率的最大影响因素,其最佳水平分别为125℃和0.93%.结合实际情况,最佳提取工艺条件可为:浸提温度95~100℃、浸提时间6h、料液质量比1:90、KCl质量分数0.93%.  相似文献   

7.
烤烟总糖、蛋白质及施木克值与土壤养分的关系分析   总被引:1,自引:0,他引:1  
该文分析了云南省保山烟区195份烤烟样品总糖、蛋白质及施木克值与土壤养分的关系.结果表明:①5县区烟叶平均总糖质量分数变异系数在10%以内,变幅以施甸县最大.蛋白质质量分数接近优质烟叶标准,平均质量分数以施甸(9.28%)最高,昌宁(8.19%)较低;②保山烟区烤烟总糖质量分数与速效钾、有效铜、有效锌和有效硼质量分数呈极显著正相关;蛋白质质量分数与碱解氮、速效磷、有效铁、有效锰和有效硫质量分数呈极显著正相关;施木克值与pH值、速效磷和有效硫质量分数呈显著负相关,与碱解氮、有效铁和有效锰质量分数呈极显著负相关;③该地区属于北回归线区域火山灰土壤特色优质烟区,土壤呈中性微酸,有机质质量分数丰富,总体供氮水平较高,速效磷质量分数中等,速效钾质量分数中等偏上,多数烟区中微量元素质量分数丰富;④最后构建了保山烟区烤烟总糖、蛋白质及施木克值与土壤养分指标间的双重筛选逐步回归分析方程.  相似文献   

8.
半干法制备高结合磷淀粉磷酸酯的研究   总被引:8,自引:0,他引:8  
以木薯淀粉为原材料、三聚磷酸钠为酯化剂、尿素为催化剂,半干法制备了高结合磷淀粉磷酸酯。探讨了反应温度、反应时间、尿素用量、pH值和磷酸盐用量对结合磷含量和反应效率的影响,确定了最佳的反应条件,当淀粉用量为100g(绝干),蒸馏水用量为100mL时,反应温度150℃,反应时间1h,尿素用量2g,pH5.0,三聚磷酸钠用量5g,产品的结合磷含量1.19%,反应效率55.32%。  相似文献   

9.
几种发酵菌剂在餐厨垃圾发酵过程中的效果比较   总被引:1,自引:0,他引:1  
为了研究餐厨垃圾制成有机肥料的发酵技术,向餐厨垃圾中分别添加发育复合菌群(EM菌剂)、酵素菌和有机废弃物发酵菌曲,通过其物理化学性质的变化比较不同发酵菌在餐厨垃圾发酵过程中的效果.结果表明,添加EM菌的餐厨垃圾发酵速度较快,其臭味在发酵第3天即消失,变成酸味,垃圾表面长出大量菌丝和菌斑;其电导率p在发酵第2天较高,之后逐渐降低;pH值一直处在酸性范围;水的质量分数则一直稳定在83%左右.添加酵素菌和有机废弃物发酵菌曲的餐厨垃圾分别在发酵第5天和第6天才逐渐长出菌斑,且一直有臭味,颜色逐渐变为灰色,最后出现虫蛆;前者的P在发酵过程中一直低于对照,后者在发酵第4~7天一直高于对照;两者的pH值一直处在中性偏碱范围.EM菌更适用于餐厨垃圾的发酵.可为餐厨垃圾的发酵技术和资源化处理研究提供参考.  相似文献   

10.
为了分析引起张家港市樟树叶片失绿黄化的主要原因,以张家港市4条主要街道两旁发生叶片黄化樟树的立地土壤为研究对象,以叶片正常樟树的立地土壤为参照对象,采集0~20 cm及20~40 cm土层中的土样,对土样进行理化性质的测定,并研究了黄化樟树与土壤理化性质之间的关系.研究结果表明:黄化樟树立地土壤pH以及HCO3-、有效磷和有效铜的质量分数均高于正常株,而有机质、速效氮、速效钾、有效铁、有效锰和有效锌的质量分数低于正常株;土壤的pH以及HCO3-、有效磷、有效铜的质量分数与有效铁质量分数之间为负相关,而土壤有机质、速效氮、速效钾、有效锰、有效锌的质量分数与有效铁质量分数之间为正相关.  相似文献   

11.
Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.  相似文献   

12.
The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3~4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰~ -7.8‰, PDB) and matrix dolomites (-6.6‰~ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084~0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078~0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.  相似文献   

13.
理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。  相似文献   

14.
As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.  相似文献   

15.
AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…  相似文献   

16.
There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.  相似文献   

17.
正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-  相似文献   

18.
We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-  相似文献   

19.
正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that  相似文献   

20.
For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the  相似文献   

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