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With geographic information system (GIS), the ecological water requirement for forests in the Jinghe watershed, western China was estimated.


Employing Arc/Info GIS, the tree species diversity and rarity, disturbance degree, protection of channel system, and classification management in the Maoershan National Forest Park were described, and used as the input factors of NN.


Division of afforestation site type in the watershed of Wangjiagou, West Shanxi through GIS


The results show that we can model the spatial changes of vegetation suitability with a combination of topographic analyses based on DEM and GIS functions.


We also demonstrate these spatial changes on the screen using Visual Basic language and GIS functions, which will help decision makers to have a clear view of species and site suitability changes over large areas.

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 An investigation of the rheological relationships between shear stress shear rate apparent bulk viscosity temperature was carried out by examining the viscous flow of slightly milled native Hevea rubber (i) The Eisenschitz's equation for nonNewtonian flow has been verified by the experiments on the dependence of shear rate on shear stress. By this equation, the apparent viscosity can be referred to the Newtonian viscosity η_0 (at σ=0). The parameter (G_i=3.30×10~5 dynes/cm~2), interpreted as an internal... An investigation of the rheological relationships between shear stress shear rate apparent bulk viscosity temperature was carried out by examining the viscous flow of slightly milled native Hevea rubber (i) The Eisenschitz's equation for nonNewtonian flow has been verified by the experiments on the dependence of shear rate on shear stress. By this equation, the apparent viscosity can be referred to the Newtonian viscosity η_0 (at σ=0). The parameter (G_i=3.30×10~5 dynes/cm~2), interpreted as an internal modulus of rigidity, was found to be practically independent of temperature in the range of 5090℃, thus agreeing with the results by treating Saunder and Treloar's data. (ii) For the shear rate dependence of apparent viscosity, when the number of Khun segments per unit volume was taken into account for the calculation of retardation time τ_1=2.84η_0 [J_e]_∞, the DebyeBueche's equation was found to be able to fit into our data at moderate low shear rates. The values of steadystate elastic compliance [J_e]_∞ were determined by elasticrecovery experiments. Furthermore, the internal shear modulus Gi could be thus calculated by combining the Eisenschitz's equation with the DebyeBueche's one. (iii) From the experiments on the temperature dependence of viscous flow under various stresses, the apparent activation energy ΔE_η was found to be 12.7 kcal/mole; and therefrom, by estimation, the unit of flowthe Eyring segment would be 30 carbon atoms long. All determinations of the flow rate under constant stress were carried out in a Hppler parallelplate plastometer, used as a viscoelasticityrheometer according to the theory developed by Dienes.  1.本實驗採用了Hoeppler平行板塑性計,按照定應力壓縮形變法的理論,在中温時對國產天然橡膠的本體粘性流動進行了流變學研究。 2.在3090°與2501500克/厘米～2的荷重範圍內,測定了貌似本體粘度η_a,內切模數G_i與貌似活化能ΔE_η。所測得的G_i=3.30×10～5達因/厘米～2與ΔE_η=12.7千卡/克分子,在一定温度範圍(5090°)內爲不依賴於温度的常數。對所測天然橡膠估計所得的粘流鰱段長約30個碳原子。 3.從粘性流動的切變速率dγ/dt依賴於切應力σ的關係中,獲得了Eisenschitz早已衍導出的,但迄未在高聚物的本體粘性流動中獲得例證时非牛頓流動流公式。該式復以Saunder及Treloar的數據重加處理而證實之。 4.從切變速率對貌似本體粘度的影響上,檢驗了DebyeBueche的理論式。現改用單位體積內彈性鍵段計算推遲時間,τ_1=2.84η_0·[J_e]∞,其中穩態彈性柔數[J_e]∞。係由彈性同復實驗測得。經如此處理後,該式在較低切變速率時筒能與實驗結果相符。 5.若以Eisenschitz式與DebyeBueche式相結合,則亦可計得內切模數G_i,並藉... 1.本實驗採用了Hoeppler平行板塑性計,按照定應力壓縮形變法的理論,在中温時對國產天然橡膠的本體粘性流動進行了流變學研究。 2.在3090°與2501500克/厘米～2的荷重範圍內,測定了貌似本體粘度η_a,內切模數G_i與貌似活化能ΔE_η。所測得的G_i=3.30×10～5達因/厘米～2與ΔE_η=12.7千卡/克分子,在一定温度範圍(5090°)內爲不依賴於温度的常數。對所測天然橡膠估計所得的粘流鰱段長約30個碳原子。 3.從粘性流動的切變速率dγ/dt依賴於切應力σ的關係中,獲得了Eisenschitz早已衍導出的,但迄未在高聚物的本體粘性流動中獲得例證时非牛頓流動流公式。該式復以Saunder及Treloar的數據重加處理而證實之。 4.從切變速率對貌似本體粘度的影響上,檢驗了DebyeBueche的理論式。現改用單位體積內彈性鍵段計算推遲時間,τ_1=2.84η_0·[J_e]∞,其中穩態彈性柔數[J_e]∞。係由彈性同復實驗測得。經如此處理後,該式在較低切變速率時筒能與實驗結果相符。 5.若以Eisenschitz式與DebyeBueche式相結合,則亦可計得內切模數G_i,並藉知貌似本體粘度隨切變速率增高而降低的現象,乃係由於發生內切應變γ_i=σ/G_i之故。  βDichroine is one of the three alkaioids isolated by Chou et al. from Dichroa febrifuga Lour., a Chinese antimalarial herb. The antimalarial activity of this alkaloid has been shown to be 50 times that of quinine. Besides, many other aspects of the pharmacology of the dichroines have been described. This paper reports a method for the determination of βdichroine in biological materials and the absorption, distribution, and excretion of this alkaloid in rats. The biological materials (tissue homogenates, blood,... βDichroine is one of the three alkaioids isolated by Chou et al. from Dichroa febrifuga Lour., a Chinese antimalarial herb. The antimalarial activity of this alkaloid has been shown to be 50 times that of quinine. Besides, many other aspects of the pharmacology of the dichroines have been described. This paper reports a method for the determination of βdichroine in biological materials and the absorption, distribution, and excretion of this alkaloid in rats. The biological materials (tissue homogenates, blood, urine, bile, and diluted faeces) were saturated with sodium chloride and extracted with chloroform at pH9. The chloroform layer was reacted with methyl orange reagent and the βdichroine content deterined colorimetrically. This method was shown to possess a high degree of specificity for βdichroine in tissues. Since normal excreta contains substances which behave similarly as βdichroine, an eightplate countercurrent distribution analysis was applied to study the excretion of the alkaloid. When given orally to rats,βdichroine disappeared rapidly from the gastrointestinal tract since one hour after a dose of 10 mg/kg only 58％ of the administered dose could be recovered from the GItract. However, about 30％ still remained four hours after administration of the drug. One hour after βdichroine was given intravenously to a rat, the highest concentration was found in the kidneys. Moderate levels were found in the heart, spleen, liver, fat, and muscle, whereas very low levels were present in the blood. Only 16％ of an administered dose was excreted in the urine in a 24hour period. Very little was excreted in the faeces and no βdichroine was found in the bile.  本文报告用甲基橙法并结合反流分布法,测定常山碱乙在大鼠体内的吸收、分布和排泄。这些结果表示常山碱乙口服后在胃肠道消失很快,1小时已消失40％,但4小时仍有30％存在。服药后大鼠都出现精神抑制和致泻症状。一鼠在给常山碱乙7.5毫克后不到4小时已死亡。可见常山碱乙在胃肠道能很好地吸收。常山碱乙静脉注射后很快离开血液,其分布以腎最高,心、肝、肌肉、脂肪及脾次之。但血中水平很低,给药后1小时平均每毫升血只含2微克。常山碱乙进入体内后,只16％左右以原形由尿排出体外,粪中只有极少量,而胆汁中几乎没有。  In reference to a theorem proved by Sugawara and Kanazawa together with recent studies of asymptotic behaviour by Omnes, the subtration in the dispersion relations of Gi(t) and Ti,(t) is discussed. The contributions to the r,(t) and Fπ,(0 by the "far away" singularities are accounted for more carefully; the results so obtained seem to agree pretty well with both the electric and magnetic isotopic vector form factors; the Ti,(t) satisfies the requirement proposed by Vick from the analysis of πN scattering... In reference to a theorem proved by Sugawara and Kanazawa together with recent studies of asymptotic behaviour by Omnes, the subtration in the dispersion relations of Gi(t) and Ti,(t) is discussed. The contributions to the r,(t) and Fπ,(0 by the "far away" singularities are accounted for more carefully; the results so obtained seem to agree pretty well with both the electric and magnetic isotopic vector form factors; the Ti,(t) satisfies the requirement proposed by Vick from the analysis of πN scattering data. Our calculation also shows that the total isotopic vector charge and magnetic moment are mainly due to the 2π intermediate state contribution; it is very probable that there exist no core point charge and magnetic moment at all.  本文根据Sugawara和Kanazawa所证明的一个定理和Omnes关于渐近行为的研究,讨论了Gi(t)和Гi(t)色散关系的減出问题。比较仔细地考虑了Гi(t)和Fπ(t)中远区奇异性的贡献,所得的结果可以同时很好地符合电形式因子和磁形式因子。其中Гi(t)并满足Vick从πN实验分析中所提出的要求。计算结果还表明,核子的矢量总电荷和总磁矩绝大部分是由2π中间态贡献的,核子的核心点电荷和点磁矩很有可能等于零。   << 更多相关文摘 
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