Search

Distribution of rare earth elements (REEs) in six speciations extracted from coal and coal gangue and their combustion products (slag and fly ash) generated by three different power plants in China were determined by sequential extraction procedure combined with inductively coupled plasma mass spectrometry method. The results show that the REEs mainly occurred as acid soluble and silicate & aluminosilicate fraction, e.g., approximately 42.54% and 45.62% in coal gangue, 32.85% and 57.13% in lignite, and 18.10% and 75.46% in bituminous coal, respectively. However, REEs in the combustion products were mainly presented in silicate & aluminosilicate fraction regardless of coal or coal gangue, reaching up to approximately 80% of the total REEs content. During combustion, around 36%, 23%, and 5% from the other five fractions (water soluble, ion-exchangeable, acid soluble, organic, and sulfide) were transformed to silicate & aluminosilicate fraction from coal gangue, lignite, and bituminous coal, respectively. In the case of coal or coal gangue, the amount of each REEs in the same extracted fraction was different, but the distribution trend of REEs from La to Lu in each fraction was followed in the same rule. In the case of slag and fly ash generated from coal or coal gangue, distribution of REEs from La to Lu in each fraction showed the different trend between fly ash and slag. This was due to the fly ash exposed in flue gas system was much longer than the time for slag formation.

Biomass is considered to be one of the most important renewable energy sources and will become an important part of future sustainable energy system. Liquefaction is a promising thermochemical conversion process that is applied to convert biomass into bio-oil (target product), biochar, and gases. The process is usually carried out in water or another suitable solvent at 250–400 °C under pressures of 5–25 MPa. This chapter firstly collects and sorts out the available review literatures on the liquefaction of biomass. Next, the effects of processing parameters on the liquefaction of biomass are briefly summarized. Then, the characterization and application studies of biochar (solid-phase product) are discussed. Finally, the main upgradation methods of bio-oil (liquid-phase product) are introduced. The ultimate aim of this chapter is to offer some reference for the study of biomass liquefaction.

Taking a rise steel as a study, study response of the structure to the dynamic characteristics under fluctuating wind load. The results showed that: deformation of structure under the fluctuating wind load is shear deformation; Structural displacement response curve is similar to the curve of the pressure time history. Because of consider different heights the structure of spatial correlation affect, Displacement positions on different floors response curves are differ.

In consider of construction characteristics of drilling bitten pile in Kunming metro engineering, this paper study on preparation and performance of super retarded concrete. Meanwhile, this paper find appropriate raw materials and mixing amount, which can meet construction requirement of high flowability and long setting time for this engineering. Combined theory with experiments, it lay the foundation of popularization and application of super retarded concrete to find the influence law of performance of super retarded concrete by mixing amount of all materials.

This paper introduces a variety of viscous damper installation form, including brace, herringbone and cantilever wall installation. By an example, install the bracing form, herringbone installation form and type cantilever wall installation condition are compared, And to calculate the results of its damping effect has carried on the comparative study, The superiority of the cantilever wall type layout pattern is obtained.

For the problem of module division for distributed reconfigurable satellite system. A satellite function tree top-down is set up in this paper. And the genetic algorithm was applied in the module division. Finally the entire satellite was decomposed into various standard parts. In practice, users only need to combine those standard parts into a specific function module according to the requirements. Then send those modules into their orbit. And those modules through the way of formation flight, wireless connection to fulfill the task. Considering China's space development strategy, satellite systems long life and high reliability, upgrading, expansibility, satellite systems planning, running, production all kinds of uncertainty factors. Finally the satellite system was divided into 15 standard parts.

The robustH∞control for spacecraft rendezvous with a noncooperative target is addressed in this paper. The relative motion of chaser and noncooperative target is firstly modeled as the uncertain system, which contains uncertain orbit parameter and mass. Then theH∞performance and finite time performance are proposed, and a robustH∞controller is developed to drive the chaser to rendezvous with the non-cooperative target in the presence of control input saturation, measurement error, and thrust error. The linear matrix inequality technology is used to derive the sufficient condition of the proposed controller. An illustrative example is finally provided to demonstrate the effectiveness of the controller.

In order to study the structure random vibration analysis technology that material properties and temperature should be considered. We have developed a set of structure random vibration parameter engineering analysis tools that under thermal environment conditions. This paper, mainly introduces this software’s architecture, development process and function characteristics. This software is developed based on NASTRAN. User not only can establish a ball cone column finite element model according to actual demand but also can select model’s material properties. At last, we have an example dealt with this software. The analysis results of temperature field, stress modal and random vibration are in good effect. And reached the anticipate design goals of this software

Background. The aim of this study is to investigate the relationship between approximate entropy (ApEn) of fetal heart rate (FHR) with umbilical blood gas parameters and the power spectrum of FHR variability in Chinese and to test whether ApEn of FHR variability could be used as a predictor of fetal distress in women at term pregnancy. Methods. Sixty-seven pregnant women with singleton, term fetus were recruited for the recording of FHR variability and the data were used for the estimate of ApEn. Blood gases after birth were measured through umbilical artery. Results. In all 67 neonates, there was some amount of interinfant variability in the ApEn values with a mean of 1.139 ± 0.169. The ApEn values were significantly ( P < 0.05) correlated with pO 2 , SO 2 , pCO 2 , pH, HCO 3 , or base excess (BE). The 15 fetuses with low ApEn (ApEn

We studied the effects of different respiratory patterns, namely, spontaneous breathing, paced breathing (at a rate of 10 breaths/min and at their mean spontaneous breathing frequency) and breath holding, on the nonlinear characteristics of heart rate variability (HRV). The results showed that paced breathing at both rates significantly diminished the nonlinearity of HRV detected by the Volterra-Wiener series method in comparison with spontaneous breathing, while breath holding increased it. These findings indicate spontaneous breathing rate is probably optimum to maintain cardiopulmonary coupling nonlinearly, and thus to minimize the influence on cardiovascular variabilities.

A paradox regarding the classic power spectral analysis of heart rate variability (HRV) is whether the characteristic high- (HF) and low-frequency (LF) spectral peaks represent stochastic or chaotic phenomena. Resolution of this fundamental issue is key to unraveling the mechanisms of HRV, which is critical to its proper use as a noninvasive marker for cardiac mortality risk assessment and stratification in congestive heart failure (CHF) and other cardiac dysfunctions. However, conventional techniques of nonlinear time series analysis generally lack sufficient sensitivity, specificity and robustness to discriminate chaos from random noise, much less quantify the chaos level. Here, we apply a ‘litmus test’ for heartbeat chaos based on a novel noise titration assay which affords a robust, specific, time-resolved and quantitative measure of the relative chaos level. Noise titration of running short-segment Holter tachograms from healthy subjects revealed circadian-dependent (or sleep/wake-dependent) heartbeat chaos that was linked to the HF component (respiratory sinus arrhythmia). The relative ‘HF chaos’ levels were similar in young and elderly subjects despite proportional age-related decreases in HF and LF power. In contrast, the near-regular heartbeat in CHF patients was primarily nonchaotic except punctuated by undetected ectopic beats and other abnormal beats, causing transient chaos. Such profound circadian-, age- and CHF-dependent changes in the chaotic and spectral characteristics of HRV were accompanied by little changes in approximate entropy, a measure of signal irregularity. The salient chaotic signatures of HRV in these subject groups reveal distinct autonomic, cardiac, respiratory and circadian/sleep-wake mechanisms that distinguish health and aging from CHF.

Circadian rhythms of heart rate variability have been widely studied in recent years. However, most previous reports described such rhythms in terms of normalized units of the low- and high-frequency (LF and HF) spectral components. In this study, we analyzed circadian rhythms of spectral com- ponents in absolute units and found unexpected results in nor- mal subjects as well as coronary heart disease (CHD) and con- gestive heart failure (CHF) patient groups. The results indicate that the notion of sympathovagal balance needs to be re-evaluated.

Fetal heart rate variability (HRV) is subject to a number of factors, including fetal distress. The aim of this study was to investigate the power spectral distribution of fetal heart rate variability during acute hypoxemia following umbilical artery embolism and to test the hypothesis that the relative proportion of frequency domains in total power of HRV, reflects the changes in HRV during hypoxemia more closely than the absolute values.Acute hypoxemia was induced in seven catheterized late-gestation fetal sheep by repeated injections of microspheres to cause umbilical artery embolism. The very-low, low-, middle- and high-frequency domains (0-0.025, 0.025-0.125, 0.125-0.20, and 0.20-0.50 cycles/beat, respectively) were determined by power spectral analysis.Umbilical artery embolism induced marked fetal hypoxemia, hypercapnia and acidosis, accompanied by an increase in heart rate and a decrease in arterial blood pressure. These changes were associated with the increase in power over the entire frequency range and in the relative power in the low-frequency range (P0.01), and with decrease in the relative power in the high-frequency range (P0.05). Correlations were found between the relative power in the low- and high-frequency ranges and PO2 and between the relative power in these ranges and mean arterial blood pressure (P0.05), but not PCO2 or pH.The present study indicates that acute hypoxemia induced by umbilical artery embolism leads to the redistribution of power spectral density of fetal HRV and that the relative proportion of individual frequency domains may reflect the changes in HRV during acute hypoxemia more closely than the absolute power values.

Spectral analysis was used to study the coherence between the blood pressure (BP) and neuronal discharge (ND), and between the heart rate variability (HRV) and neuronal discharge variability (NDV) in the rostral ventrolateral medulla (RVLM) in rats. The discharges of 28 neurons in the RVLM were recorded. The results revealed that: (1) there is an obvious coherence (k/sup 2/=0.82/spl plusmn/0.18) between ND and BP on spectrum. These neurons were classified as cardiac-related (n=18) if the coherence value was k/sup 2//spl ges/0.80; (2) there is also an evident coherence (k/sup 2/=0.78/spl plusmn/0.13) between NDV and high frequency (HF) component of HRV. These neurons might be HRV-related (n=14) if the coherence value was k/sup 2//spl ges/0.80. It indicates the integration of cardiac cycle and respiratory rhythm in the RVLM that might be important in cardiorespiratory homeostasis.