Measurement for Spectral Response of Solar Cells

General Research Institute for Non-ferrous Metals in cooperation with Changchun Instituteof Optical and Fine Mechanics prepared an automatic measurement instrument for spectral re-sponse test of solar cells. This instrument having enough accuracy can measure at AM1.5 condi-tion. It meets the needs for measurement of spectral response for silicon, gallium arsenide solarcells.

Study on Catalytic Cracking of VGO Derived from Kazakhstan-Russian Mixed Crude

The study on options for catalytic cracking of VGO derived from the Kazakhstan-Russian mixed crude was carried out in a small-scale riser FCC unit. The influence of several catalysts and the LCC-A additive for increasing propylene yield on the distribution and quality of FCC products was analyzed. This article sets forth the possible issues arising from processing the Kazakhstan-Russian mixed crude in FCC unit and the response measures to be adopted.

A double integral method for quantitative evaluation of influence on thin-walled casing response caused by bearing uncertainties

Bearings in a gas turbine engine are the key connecting components transmitting force and motion between rotors and thin-walled flexible casing.The bearing stiffness and damping of squeeze film damper(SFD)nearby bearings are easily affected by many factors,such as assembly process,load condition and temperature variation,resulting in uncertainties.The uncertainties may influence the response of the measuring point on the casing.Hence,it is difficult to carry out the fault diagnosis,whole machine balancing and other related works.In this paper,a double integral quantitative evaluation method is proposed to simultaneously analyze the influence of two uncertain dynamic coefficients on the response amplitude and phase of casing measuring points.Meanwhile,the coupling influence of stiffness and damping accompanied by dramatic changes with rotational speeds are essentially discussed.As an example,a typical engine bearing-casing system with complex dynamic characteristics is analyzed.The impact of uncertain dynamic coefficients on the unbalance response is quantitatively evaluated.

Clinical experiment of exercise induced asthma and respiratory impedance assessed with impulse oscillometry to measure exercise response of asthmatics

Abstract Objective In order to investigate pathophysiology of exercise induced asthma (EIA), the impedance of the respiratory system was studied using impulse oscillometry (IOS). EIA is a temporary increase in airway resistance, which occurs after several minutes of strenuous exercise. Most asthmatics experience EIA. Patients and methods Respiratory impedance was measured with IOS (MasterScreen, Jaeger, Germany) in 14 healthy volunteers and 14 asthmatics as baseline value at first. The procedure of exercise challenge with an ergometer (Corival 300 Gould Co.) increased heart rate to 90% of predicted maximum values in 3-4 min and maintained for 6 min. After challenge, measurements with IOS were made immediately at 5 min intervals for 5 times. Results The maximal increase of respiratory impedance occurred at 5-10 min after exercise and the increment magnitude of peripheral resistance (99.6%) was more than that of central resistance (13.5%) in asthmatics. After challenge, R5Hz, R5Hz-R20Hz, Zrespir (total impedance), resonance frequency (Fres) and X5Hz from patients changed significantly. The increment value of R5Hz-R20Hz from asthmatics was≥0.032kpa/l·s -1 and the change ratio of X5Hz from 71.4% of asthmatics was ≥41% (2SD beyond the mean response of nonashmatics). Air trapping loop was expressed in V T Zrespir graph in 57.1% patients. All subjects underwent IOS measurement. Conclusion Exercise test can diagnose asthma and evaluate efficacy of treatment for bronchial asthma. Because the patients usually have shortness of breath after exercise challenge, the measurement with spirometry (FEV 1) may not be accurate. IOS is based on measurement of the relationship between an external pressure pulse applied to the respiratory system and the resulting respiratory airflow. The spectral ratio of the amplitude of the pressure wave signal to the resulting flow signal constitutes the impedance of the respiratory system, from which the resistance (R) and the reactance (X, including elastance and inertance) of respiratory system in the frequency range 5Hz to 35Hz can be calculated. Our data showed that the increment value of R5Hz-R20Hz was more sensitive than other indices for detecting exercise induced asthma. The bronchoconstriction took place in peripheral airway mainly after exercise. Because obstruction of small bronchi during expiration and impedance increased abruptly, air trapping loops were expressed in V T Zrespir graph after challenge in asthmatics. Fres is the frequency point where the absolute value of elastance equals to that of inertance. X5Hz reflects the condition of compliance of lungs. Fres shifted right and change ratio of X5Hz increased after exercise were relative to the compliance decrease of lungs. The airway response of exercise challenge may be assessed more accurately and more conveniently with IOS that did not require a maximal inspiration and forced expiration.

Application of piezoelectric transient response in transducer acoustic power measurement

To explore a more convenient method for measuring the focused ultrasound power, a piezoelectric ceramic plate was used to receive ultrasonic signal directly. Due to an acoustic force acts on the surface of piezoelectric ceramic plate, the piezoelectric response was obtained by means of electromechanical analogy, which was composed of voltage response caused by forced vibration and high frequency attenuation response caused by natural vibration. The conversion relationship between output signal of piezoelectric ceramic plate and acoustic power of transducer was analyzed. The envelope of output piezoelectric signal was extracted in twice, and a voltage amplitude curve with sinusoidal distribution that could describe the changes of acoustic power was obtained. Under different drive voltage of transducer, the maximum peak voltage of envelope curve was found respectively. Their squared values were made a linear fitting with acoustic power measured by acoustic power meter, and then the proportional coefficient of theoretical relational expression was calibrated. The experimental results are in good agreement with the theory. The relative error between calibrated theoretical acoustic power and that measured by acoustic power meter was less than 8.7%. The paper can provide a guideline for measuring acoustic power of transducer by using piezoelectric signal.

Frequency response of loudspeakers by measuring theinduced e.m.f

The technique of coupling two loudspeakers to obtain a signal proportional to the velocity of the cone is known. The sound at a distant point from a loudspeaker is related to the diaphragm displacement. Since the induced e.m.f is proportional to the voice coil velocity,measurement of induced e.m.f enables us to obtain the displacement of the cone and hence we can plot the SPL curve for a loudspeaker. This method has some limitations in that it is particularly applicable only when one is interested in using the output of the second speaker used as a sensor in some further applications.

Clinical observation on the time-effect relationship of moxibustion for primary dysmenorrhea due to stagnation and congelation of cold-damp

Objective:To observe the time-effect relationship of moxibustion for primary dysmenorrhea(PD)due to stagnation and congelation of cold-damp,thus explore the optimal choice of moxibustion duration,and provide evidence for achieving satisfactory efficacy in moxibustion treatment.Methods:A total of 90 patients with PD due to stagnatin and congelation of cold-damp were divided into three groups by the random number table method,with 30 cases in each group.All the patients in the three groups were given moxibustion treatment at Guanyuan(CV 4),20 min in group A,40 min in group B and 60 min in group C.The changes in the pain measurement score in the three groups were observed after treatment.Results:After treatment,there were significant differences in the clinical efficacy among the three groups(P<0.05);the clinical efficacy was better in group B and group C than that in group A(P<0.05),and that in group B was better than that in group C(P<0.05).Besides,the pain measurement score changed significantly after treatment in the three groups(all P<0.05),and the between-group differences were also statistically significant(P<0.05);the pain measurement scores in group B and group C were lower than that in group A(P<0.05),and that in group B was lower than that in group C(P<0.05).Conclusion:Given the same stimulating frequency and intervention time of moxibustion,40-minute duration demonstrates relatively better efficacy for PD due to stagnation and congelation of cold-damp.

Modeling and simulation of voluntary employee turnover using catastrophe theory: A case study on a manufacturing enterprise in China

The Lewisian turning-point obviously increase the labor costs of Chinese manufacturing firms,it made the employee turnover to become the key problem that how to keep the enterprise human resource stability.Here,the conceptual catastrophe model of employee turnover is built from the new perspective of empirical study and catastrophe theory.In particular,we developed a parameter estimation method of the Cusp catastrophe model based on qualitative simulation and fuzzy math,and then to demonstrate the rationality and robustness of this method by a practical case on a manufacturing enterprise.In the end,a series of virtual experiments are carried out for the employee turnover in the period of China’s economic transformation.The main results are that,how to measure the warning,critical and mutation area of employee turnover;the real relationship between the complex economic environment and the demission of employees;the control policy from the macroscopic governmental measures and microscopic enterprise ways.