查询词典 f ratio

In general a partial derivative of f with respect to a variable q is the ratio of df to dq when certain other variables are held fixed.

一般来说函数f对某一特定变数q的偏微分所代表的是在其余变数固定的情形之下，df对dq的比值。

The optimal processing conditions are as follows: roasting temperature at 1 000℃, roasting time for 40 min, the ratio of NbH dosage to theoretic dosage at 1.1. The specific capacity of niobium suboxide of preparation by agate grind procedure is 69.50 mF·V·g-1, the loss is 11.25%, the leakage current is 1.8×10-4A·F-1·V-1, and the electrical properties are better than that of the national standard (GB/T 3136-1995) of FTa16-300 tantalum powder for capacitor.

用正交试验法及方差分析对玛瑙研磨工艺进行优化，得到制备低价铌氧化物最佳条件是：焙烧温度为1 000℃，焙烧时间为40 min， NbH用量与理论量之比为1.1，所制得的产物杂质含量低，比容为69.50mF·V·g-1，损耗为11.25%，漏电流为1.8×10-4A·F-1·V-1，其电性能指标高于FTa16—300电容器钽粉国家标准(GB/T 3136—1995)所规定的值。

Based on the rigorous analysis of the kinetic process of both primary and secondary electrons, the related surface charges were analyzed, and the energy gain of emitted electrons was proportional to the square of the ratio between the tangential and normal component of electric field. In this process, the image force of mirror charges would result in an energy loss. Meanwhile, the effect of field alternation of power frequency ac voltage on electron movement could be ignored.

在前人工作的基础上，进一步严格推导了场致一次发射电子和二次电子的运动方程，分析了电子发射引起的绝缘材料表面带电，表明电子发射后的能量增益正比于场强的切向与法向分量比值 F /// F ^的二次方；同时考虑了在电子发射和运动过程中电荷镜像力的作用，并探讨了交流电压下表面带电的情形，认为当考虑电荷镜像力的作用时，电子的能量增益可能变小，而工频交流电压下电场交变对电子运动的影响可以忽略。

Holding the bow is like a teeterboard supported by thumb as the pivot and the cooperated forcing of forefinger and little finger produces a moment M. The "P-x-M Line Method" shows when playing a down bow, M increases with x and gradually changes its direction and this process is determined by P, the gravity and barycenter of bow. The "P-x-F Plane Method" shows that the most force-saving bowing path should locate in the lower part of this plane. The analyses of "Helmholtz Motion" and "Schelleng Diagram" indicate P and its range is in direct ratio with volume, velocity of bow, the approaching degree of the bow to the bridge and has some relationship with the quality of string and bow.

国内近期出现了用物理模型来研究小提琴运弓问题的尝试本文第一部分首先指出握弓类似于一个以***(F3)为支点的跷跷板，主要以食指(F1)和小指(F2)的施力配合，产生握弓力矩M；随后用"P-x-M直线法"证实：演奏下弓是M随的***而逐渐增大并转换方向的***，此***取决于P、弓的重力和重心；并首创"P-x-F平面法"，在x，F1，F2空间中证实：省力的运弓路径应在该平面中处于较低的位置第二部分通过分析"赫尔姆霍茨运动"和"Schelleng图表"指出：P及其变化范围和音量、弓速、弓与琴码的接近程度成正比，并与琴弦和弓自身的性质有关

In which F is the water equivalence factor of the Reagent; X is the volume, in mL, of the Reagent added after introduction of the specimen; X is the volume, in mL, of standardized Water Solution required to neutralize the unconsumed Reagent; and R is the ratio, V/25 (mL Reagent/mL Water Solution), determined from the Standardization of Water Solution for Residual Titration.

其中F是试剂与水的等价因子；X加入样品后加入的卡尔试剂体积，单位ml；X是标准水溶液中和未反应试剂所消耗的体积，单位ml，R是一个比值，V/25（单位卡尔试剂/单位标准水溶液）。

The F-15's maneuverability and acceleration are based on high engine thrust-to-weight ratio and low wing loading.

F-15具有高度的机动性和加速性能，其推重比极高，超过1，而单位翼载荷则很低。

The analysis of the mechanical sensitivity and the density indicated that the system which contained the F rubber, ceresin and graphite had a very good effect on shaping performance and mechanical sensitivity. Both the friction and impact sensitivity were 0. When the pressure reaches to 900 kg/cm2 the density ratio could achieve 99.2%.

对机械感度和压制药柱密度的测量和分析，研究结果表明在九种粘结-钝感体系中，F橡胶、蜡类钝感剂、石墨组成的粘结-钝感体系成型性能和机械感度最为优越，其摩擦和撞击感度都为0.00，900比压时可压系数可达到99.2%。

Electron donating substituent CH〓, OCH〓 and 4, 5-benzo make λ〓 red shift, electron with -drawing substituent F, Cl and CF〓 make λ〓 hypsochromic shift; b The W〓 is bigger than relative symmetrical carbocyanines, and the ratio of 0-1＇ and 0-0＇ transition intensity increase with the increase of σ〓; c The absorption and the fluorescence spectra are mirror image, and the λ〓 have a good linear relationship; d The Stokes shift △λ〓 and the Hammett σ〓 constant have a good linear relationship.

研究了染料的光物理性质，①苯环上取代基影响染料的λ〓和摩尔消光系数，相对于H，给电子取代基CH〓、OCH〓、4，5-benzo使λ〓红移，摩尔消光系数减小，吸电子取代基F、Cl、CF〓使λ〓蓝移，摩尔消光系数减小；②化合物吸收峰的半峰宽较相应的对称染料的大，且振动肩部与最大吸收峰的强度比随σ〓增大而增大；③吸收光谱与荧光光谱呈镜像关系，且λ〓与λ〓呈良好的线性关系；④化合物的Stokes位移△λ〓与取代基的Hammett σ〓常数呈线性关系。

Growing sweet corn in summer could absorb redundant nutritional ingredients largely in the soil, but the number of fungi was high and the ratio of B/F is not obvious compared with CK. On the contrary, planting leafy vegetables had no obvious effect on the composing of soil microbe and the decruce of the number of pathogen of cucumber, although it could reduce the content of salty in the soil. The crop green manure of villose vetch could reduce the content of salty in the degree, but the sum of microbe in the soil reduced a little.

夏季休闲期间种植甜玉米可大量吸收土壤中多余的营养成分，但真菌数量偏高，B/F值与对照相比相差不大；种植速生叶菜虽然能降低土壤盐分含量，但对降低黄瓜致病菌数量和改善微生物区系组成方面无显著效果；豆科作物毛苕子在一定程度上降低了土壤盐分含量，但土壤微生物总量有所减少。

A synthesis method of 2-(2'-hydroxyl-4'-benzoyloxy-phenyl)-2H-benzotriazole and derivatives thereof is provided, and is characterized in that 2-(2', 4'-dihydroxyphenyl)-5-X-2H-benzotriazole and benzoyl chloride are taken as raw materials for reaction in solvent for 1-8 hours under the temperature of 50-140 DEC C with the mole ratio of 1 to 0.95-1.1, wherein, the amount of the solvent is 2 to 20 times that of the 2-(2', 4'-dihydroxyphenyl)-5-X-2H-benzotriazole and X represents H, F, Cl, Br.

一种2-(2′-羟基-4′-苯甲酸基苯基)-2H-苯并三唑及其衍生物的合成方法，其特征是，以2-(2′，4′-二羟基苯基)-5-X-2H-苯并三唑和苯甲酰氯为原料，在溶剂中进行反应，反应温度50℃～140℃，反应时间1～8小时，反应原料摩尔比2-(2′，4′-二羟基苯基)-5-X-2H-苯并三唑∶苯甲酰氯为1∶0.95～1.1，溶剂用量为2-(2′，4′-二羟基苯基)-5-X-2H-苯并三唑重量的2～20倍，其中X代表H、F、Cl、Br，具有反应条件温和、反应收率高和产物纯度高的特点。

With Death guitarist Schuldiner adopting vocal duties, the band made a major impact on the scene.

随着死亡的吉他手Schuldiner接受主唱的职务，乐队在现实中树立了重要的影响。

But he could still end up breakfasting on Swiss-government issue muesli because all six are accused of nicking around 45 million pounds they should have paid to FIFA.

不过他最后仍有可能沦为瑞士政府&议事餐桌&上的一道早餐，因为这所有六个人都被指控把本应支付给国际足联的大约4500万英镑骗了个精光。