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     When the Ir/Al_2O_3 catalyst was reduced by H_2 in the region 200 —400℃, a strong band appeared near 2030 cm~(-1).
     用红外光谱法表征了Ir/Al_2O_3催化剂的表面性质。 发现该催化剂在200—400℃通H_2还原后表面有Ir—H键存在。
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     ~(192)Ir—HDR brachytherapy combining with external beam radiotherapy for carcinoma of the oral cavity
     ~(192)Ir—HDR放疗合并外照射治疗口腔癌报道
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     At the same time, the plasma ir-β-EP in this patient group was 623.64±468.22pg/ml, which was also significantly higher than its pre-anaesthetic value (P<0.01).
     这组病人手术15min后的血浆β-内啡肽免疫活性物质(ir—β—EP)含量为623.64±468.22pg/ml。 与麻醉前比较亦明显升高(P<0.01)。
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     It can be assigned to absorption peak of Ir-H bond stretching vibration according to the results of H-D exchange.
     并用D_2交换法归属了~2030cm~(-1)的强吸收峰属Ir—H键伸缩振动。
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     EVALUATION OF IR-8 AND IR-24 IN EARLY RICE BREEDING
     IR—8和IR—24在早稻育种中的利用价值
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     , Ir.
     Ir.
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     , Ir.
     ,Ir.
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     The Construction of L-S Measurement onIR~2
     IR~2上LS测度的构造
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     Distinguishing the Polymers by Combining IR and DSC
     IRDSC联合鉴定高聚物
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  ir
The synthesized compounds have been characterized on the basis of elemental analyses, infrared spectroscopy (IR), and nuclear magnetic resonance (NMR).
      
Their structures were determined by IR spectra, 1H nuclear magnetic resonance (NMR), 13C NMR, and elemental analysis.
      
The polymers were characterized by IR spectra, thermal-weight analysis, scanning electron microscope and laser particle size analysis.
      
The structure of the B3 monomer was confirmed by MS, 1H NMR/IR.
      
The structure of the titled compound is determined by infrared spectrum(IR), proton nuclear magnetic resonance (HNMR), and mass spectrum (MS) and elemental analysis (EA).
      
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The average nuclear level spacings of In, Ir and Au are estimated from the beta-ray activities induced by the primary photo-neutrons emitted from a Ra+Be source. A Geiger-Muller counter made of aluminum is used for measuring the induced activities. The saturated induced activities for the three elements are found to be 0.665±0.23 0.982±.03l, 0.453±0.21 (no./sec.) respectively. The estimation for the average nuclear level spacings is made in accordance with Breit-Wigner's one level formula, the resnlts...

The average nuclear level spacings of In, Ir and Au are estimated from the beta-ray activities induced by the primary photo-neutrons emitted from a Ra+Be source. A Geiger-Muller counter made of aluminum is used for measuring the induced activities. The saturated induced activities for the three elements are found to be 0.665±0.23 0.982±.03l, 0.453±0.21 (no./sec.) respectively. The estimation for the average nuclear level spacings is made in accordance with Breit-Wigner's one level formula, the resnlts being 5.6, 15 and 6 volts for In, Ir, Au respectively. The spacing of Ir is probably somewhat over estimated since the values of the energy and absorption coefficient of the resonance neutron group, used in the estimation, are not very accurate.

作者用镭加钡之光感中子以射击铟铱金三元素,而以一铝质盖密计(GeigerMuller counter)测其感应放射能。得各元素感应放射能之饱值,铟为0.665士.023.铱为0.982±.031,金为0.453±.024.依白威二氏(Breit-Wigner)之单能准式,吾人可自感应放射能之值道出原子核能准之平均间隔。所得结果,铟铱金各为5.6,15,6伏特。因计算时所用共振中子之能及吸收系数不太准确,估计所得铱之间隔大概过高。

Theories of the "dead-stop" end-point method of titration of Foulk andBawden have been studied recently by Delahay, Kies, Duyckaerts,Gauguin and Charlot, and Bradbury, but no conclusive remarks have beenobtained by these authors as to the choice of optimum experimental conditionssuch as the applied voltage, the initial concentration of the solution to betitrated, the temperature, the electrode area, the stirring rate, the resistancein the circuit and the sensitivity of the galvanometer. This situation hashandicapped...

Theories of the "dead-stop" end-point method of titration of Foulk andBawden have been studied recently by Delahay, Kies, Duyckaerts,Gauguin and Charlot, and Bradbury, but no conclusive remarks have beenobtained by these authors as to the choice of optimum experimental conditionssuch as the applied voltage, the initial concentration of the solution to betitrated, the temperature, the electrode area, the stirring rate, the resistancein the circuit and the sensitivity of the galvanometer. This situation hashandicapped the wide applicability of this method, although it yields accurateresults and requires only inexpensive equipment. In the above mentioned theories, it is generally assumed that the iR dropin the circuit may be neglected i. e., the concentration overpotential E_πis equalto the applied voltage E and will not change in the course of the titration.But it is found experimentally that the magnitude of the resistance in thecircuit will greatly effect the shape of the titration curve and the sharpness ofthe end point. In fact, if we want to increase the sensitivity of the method(i. e., to titrate very dilute solutions), it is necessary to insert a high resistance(as high as a mega ohm) in the circuit in order to have a sharp end point In view of the above considerations we have derived the equations, g=i/i_0 =xSE~(-1)(Y_B-1)/(Y_B+1), 0≤x<0.5 (1a) g=0.5SE~(-1)(Y~(1/2)-1)/(Y~(1/2)+1) x=0.5 (1b) g=(1-x)SE~(-1)(Y_A-1)/(Y_A+1), 0.51 (1e)for the intensity of current i as a function of the "fraction x being titrated"(at the end point, x=1) during the titration of A with D as shown by thefollowing reaction: A+D=B+C (2)where A/B and C/D are two reversible redox pairs. In these equations, g=the ratio of the current i at any given stage during the titrationto that i_0 which would be obtained if the concentration overpotential E_π were zero. This latter quantity is equal to the applied voltage E divided by thetotal resistance R in the circuit, i. e., i_0=E/R. S="the dead-stop titration constant" which determines the shape ofthe titration curve and is equal to the product of three quantities: 1) thediffusion current constant of A, k_A, 2) the initial concentration of A, C_0, 3)the total resistance, R; i. e., S = k_AC_0R. K=the equilibrium constant of the reaction (2). α=the ratio of the diffusion current constant of D to that of A, i. e.,α=k_D/k_A. Y_A=the ratio of the concentration of A at the anode, (A)_a, to that atthe cathode, (A)_c, i. e., Y_A = (A)_a/(A)_c; similarly, Y_B=(B)_c/(B)_a; Y_c= (C)_a/(C)_c; Y_D =(D)_c/(D)_a. Y=Y_AY_B=Y_CY_D=exp{(1-g)nFE/RT}, where n, R, T have theusual meaning as used in electrochemistry. At any given stage of titration, x and Y are known, then Y_j's (j=A, B,C, D) may be calculated as follows: Y_j=Q(Y-1)+(Q~2(Y-1)~2+Y)~(1/2) (3)In the above expression, when j=A, Q=x-0.5; when j=B, Q=0.5-x;when j=C, Q=0.5-1/x; when j=D, Q=1/x-0.5. Since g is a measurable quantity, Y is a function of g and E, so thatequation (1b) provides a convenient means to evaluate S and hence k_A. Differentiating (1c) with respect to x, we obtain (dg/dx)_(x→1)=-SE~(-1)(Y-1)/(Y+1) (4)this is the expression for the steepness of the current change near the endpoint. The theoretical titration curves and their slopes near the end point as cal-culated with the aid of the equations (1), (3) and (4) were plotted in Fig. 2 (p. 8),where the applied voltage being fixed at 59 mv but the dead-stop titrationconstant S has been varied tenthousand-fold. From this figure we may drawthe following conclusions: (1) At the given applied voltage, the larger the S the steeper the titra-tion curve. Steeper curve will give more sharp end point, but it is not ad-vantageous if the curve is too steep, since there will be no warning whenapproaching the end point and a drop of the reagent may be sufficient to causea jump from the left to the right branch of the titration curve over thecurrent minimum. The most suitable value of S is in the order of magnitudeof ten. (2) For the titration of Ce (IV) with Fe (II) at room temperature usingtwo platinum foil electrodes of area of about 0.8 square centimeters, we foundk_A is in the order of magnitude of 0.1. Since S=k_AC_0R the product of C_0and R should be in the order of magnitude of 10~2. If C_0=10~(-3)M then a resistanceof about 10~5 ohms should be inserted. (3) Since k_A=nFAD_A/δ, the factors which determine k_A are: the elec-trode area A, the diffusion coeficient D_A and the effective thickness of the diffusion layer δ, these latter quantities are effected by the temperature andthe viscosity of the solution, the rate of stirring, etc. Fig. 3 is a similar plot, but in this case S is fixed at 0.59, while E variesfrom 5.9 to 590 mv. From this figure we see that the slopes of the titrationcurves for E=295 and 590 mv are smaller than those for E=118, 59 and 5.9mv, so that an applied voltage over several hundreds mv is usually disadvan-tageous in the dead-stop titration. On the other hand, too small an appliedvoltage is also inconvenient because then a much more sensitive galvanometermust be used and the current readings will sometimes be erratic due to sometemporary polarization effects. The experimental test of the above theory will be reported in the nextcommunication.

(1)本文讨论只指示电极电流滴定法(永停法)的理论,推导考虑线路电阻的且能适用於各滴定阶段的一般公式,根据这些公式可以算出不同实验条件下的理论滴定曲线。 (2)定量讨论决定终点附近电流突跃大小的各种因素,为选择永停法的最优实验条件提供一些根据。 (3)提出测定扩散电流常数的简便方法。

An experimental verification of the theoretical peak current equation forreversible electrode reactions of the Randles-Sevcik oscillopolarography, i_p=Kn~(3/2)D~(1/2)m~(2/3)θ~(2/3)α~(1/2)cμΑ, is carried out with both single- and multisweep methods. Themultisweep method is essentially that of Delahay, while a simplified circuit isdevised for the single-sweep procedure. The constant K in the above equation has been worked out by Randlesand Sevcikc, but their values differ by some twenty-one percent. Experimentalresults...

An experimental verification of the theoretical peak current equation forreversible electrode reactions of the Randles-Sevcik oscillopolarography, i_p=Kn~(3/2)D~(1/2)m~(2/3)θ~(2/3)α~(1/2)cμΑ, is carried out with both single- and multisweep methods. Themultisweep method is essentially that of Delahay, while a simplified circuit isdevised for the single-sweep procedure. The constant K in the above equation has been worked out by Randlesand Sevcikc, but their values differ by some twenty-one percent. Experimentalresults as to which K value is correct have been contradictory. The authorspoint out that Sevcik's value of K is too low, due to the error in choosing too largea unit in his numerical integration. By taking smaller units and reperformingthe integration, the K value increases and approaches that of Randles. Thus thecorrectness of Randles' K value is ascertained and this value is used in calculatingthe theoretical slope. Their single-sweep results, with concentrations from 2×10~(-4) to 1×10~(-3) m/l andα~(1/2) from 1 to 4 volts/sec, agreement between experimental and theoretical slopesis obtained in the case of Tl~+ in m NaCl. In the case of Cd~(++) in m NaCl, experi-mental results deviate from the theoretical value, and the deviation increases withincreasing c and α~(1/2). Contrary to an unproven idea of Delahay, i_p obtained bymultisweep method is higher than that by the single-sweep procedure. However,in calculation of the theoretical values, a value of 15.0×16~(-6) obtained by polarLographic method is used for D of Tl~(+) in m NaCl. The use of the value of Dat infinite dilution is thought to be unjustified. If a D value of 15.0×10~(-6) is used,Delahay's results of Tl~+ in KNO_3 would be higher than the theoretical equationinstead of agreeing with it. This fact seems to support the findings of this paper. Various methods of correcting for capacity currents are compared and discus-sed. The authors point out that at α~(1/2) less than 2 volts/sec, the method of drawingan hbrizontal line introduces no appreciable error while at, high α, various methodsyield different results. This fact lowers the accurraey of data obtained at high α. The iR drop in the electrolytic cell and on the series resistance causes themeasured α to be different from the a actually applied on the drop electrode. Anelementary approximate correction of this effect is mentioned. Results after thiscorrection show that the deviation of Cd~(++) from theoretical at high c and α maybe due partly to this effect.

(1)以单波法及多波法验证Randles-Sevcik示波极谱理论公式之i_p~c及i_p~α~(1/2)关系,多波法用Delahay线路,单波法则用简化线路。单波法之结果,对亚铊离子在m氯化钠中,在2×10~(-4)~1×10~(-5)m浓度,α~(1/2)为1及4伏特/秒,实测结果和理论符合。镉离子在m氯化钠中,实测结果与理论有偏差,偏差随浓度及α~(1/2)加大而加大。多波法之i_p实测值高于单波法。 (2)在计算理论曲线时,作者肯定Sevcik之系数过低而采用Randles数值。亚铊离子于m氯化钠中之扩散系数D,采用极谱法测得之数值15.0×10~(-6)而不用无限稀时之D值(20.0×10~(-6))。 (3)在α~(1/2)低于2伏特/秒时,可用画水平线法扣除电容电流。在高α时各种扣除电容电流方法所得结果不同,影响结果之可靠性。 (4)电解池线路上之iR降使加在滴汞电极上之α改变。这种改变使实测i_p值偏低。作者曾作初步近似修正,结果说明α及浓度大时,镉离子实测数据对理论的偏差的一部分可能是由于iR降的作用。

 
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