拉氏变换法解微分方程引起增失解的分析

拉氏变换法解微分方程引起增失解的分析陆巧伶（扬州大学水利学院，扬州２２５００９）１拉氏变换法求解变系数线性微分方程可能会引起增失解例１求微分方程ｔ２ｙ″＝２ｔｙ′满足初始条件ｙ（０）＝ｙ′（０）＝１的解。解对方程两边取拉氏变换，记Ｌ［ｙ（ｔ）］＝Ｙ，...

音扎线加装失步振荡解列装置的必要性

呼兴电网联网后存在诸多的暂态安全稳定问题,其中乌兰浩特地区机组暂态功角稳定问题尤其突出,威胁着电网的安全稳定运行。通过对乌兰浩特地区机组暂稳问题模拟计算的分析,采取在音扎线装设失步振荡解列装置,可使系统发生故障后将失步机组从系统中解列,保证主网和解列地区电网暂态稳定。

初等方程的同解理论

本文以集论为工具,从初等方程的几个基本概念出发,推导出了初等方程的八个性质定理,对于初等方程常见的一些解法,给了理论上的说明.限于水平,缺点错误在所难免,希望得到各方面的指正.

Morphological and Anatomical Analyses of a Floral Organ Mutant in Rice

A spontaneously occurred rice ( Oryza sativa L.) mutant characterized by homeotic conversions in glumes and stamens was found in the progeny of a breeding material. The mutant plant shows degenerated glumes and morphological transformation of stamens into pistils. A mutant floret consists of 1 to 3 completely developed pistils and 4 to 6 incomplete pistils with no ovary. Some pistilloid stamens still have filaments but tipped by bulged tissue and 0 to 3 stigmas. Three ovaries in a single floret were observed in its cross and longitudinal sections. When the mutant plants were pollinated with pollens from wild type plants, one or two naked seeds instead of a caryopsis could be produced in a single floret. The mutant is controlled by a single recessive gene since its F 1 hybrid plants were restored to wild type and 3∶1 ratio of wild type to mutant plants were observed in the progeny of heterozygotes. It seems that the mutant phenotype of the homeotic conversions in glumes and stamens is similar to that of the B loss_of_function mutants in Arabidopsis and Antirrhinum .

Effects of acute hepatic damage on natriuresis and water excretion after acute normal saline loading in rats

AIMS To investigate the relationship between the liver function- al impairment and sodium and water retention. METHODS Acute liver damage model was established with carbon tetrachloride (CCl_4) administration to male Sprague-Daw- ley rats. Twenty-four and 48 hours later after CCl_4 administration, the excretion of acute sodium and water load was examined,and 24 hours later after normal saline administration,the excretion of acute sodium and water load was examined in control group. The concentration of plasma caffeine was analysed with high pressure liquid chromatograph (HPLC). The half life time of plasma caffein (Caft 1/2) sewed as a quantitative index of hepatic function. Plasma ALT was measured with Reitman method. The hepatic tis- sue was sectioned in the same site for water content measurement and pathological observation. The serumal and urinary sodium was measured with flame photometry. RESULTS Twenty-four hours later after CCl_4 administration, plasma alanine aminotransferase (ALT,n=6,37.5±12.6→ 189.4±34.4U,P<0.01) and water content of hepatic tissue (n =6,70.0%±1.1%→73.0%±1.0%,P<0.01) rose significantly,Caft 1/2 was prolonged significantly (94.9±18.9→ 326.4±85.8 minutes,P<0.01 ). The renal function of excretion of acute salt and water load declined obviously (n=6,Na^+: 92.4%±14.1%→50.1%±13.1%,P<0.01;H_2O:86.3%± 14.3%→42.1%±8.8%,P<0.01). Forty-eight hours later, the indexes above somewhat recovered,but were still markedly different from those of the control. Furthermore,the relationships betweenCaft 1/2 andALT (r=0.752,P<0.01),and between Caft 1/2 and excretory rate of sodium (r=-0.634,P<0.05) and water were still significant (r=-0. 612,P<0.01). CONCLUSIONS Caft 1/2 is a good index to assess the degree of hepatic damage. The hepatic dysfunction may be a factor caus- ing the renal excretory impairment to the acute sodium and water load.

Study on chemical failure of HMX under low temperature condition

In order to make unexploded ordnance lose explosive ability,the chemical failure of HMX that is usually used as detonating explosive and booster was studied so as to find the corresponding chemical reagents,which can decompose HMX into compounds without explosive properties.For this purpose,several decomposition experiments between HMX and NaOH,HMX and thick H2 SO,HMX and mixed acid under different temperature conditions were carried out.According to the experimental results,it can be concluded that HMX can be decomposed by a mixture of concentrated nitric acid and concentrated nitric acid with the volume ratio of 3∶1.When its decomposed level reaches 60%,HMX will not be detonated,therefore the failure purpose is achieved.

Photolytic Model of Six Degradable Mulch Plastic Films

[Objective] This study aimed to solve the mulch plastic film pollution problems in Xinjiang, in order to provide reliable theoretical basis for the research on the degradation mechanism of biodegradable plastic films. [Method] The effect of illumination intensity on the decomposition of decomposable mulching films was investigated through simulating the field condition in laboratory. Regression analysis was employed to fit the processes of film decompositions. [Result] The weight loss ratios of different types of plastic films were closely related with the illumination. There was no sundry produced during the degradation process, but the weight was reduced, indicating that degradation produced gas, thus, ultraviolet rays had destructive effect on mulch plastic films. Different types of plastic films showed significant differences in the degradation speeds, and under the same conditions, the degradation speed of S4# with the induction period of 30 d was the fastest. With the extension of uv illumination time, the degradation became cumulative degradation process. [Conclusion] Under the uv rays, the weight loss ratio and illumination hours is regarded as a positive correlation relationship. The significant inspection shows that the data fitted degradation model can be described by the logistic model of Y = a/（1＋b×e -ct）, and all the parameters show significant differences （P0.01）.

Understanding the deactivation behavior of Pt/WO3/Al2O3 catalyst in the glycerol hydrogenolysis reaction

The selective hydrogenolysis of glycerol to 1,3-propanediol is a highly important reaction for both improving the profitability of biodiesel and valorization of biomass.While intensive research efforts have been devoted to enhancing the catalytic activity and selectivity,little is focused on the stability although the latter is of paramount importance to practical applications.In this work,we investigated the stability of Pt/WO3/Al2O3 and observed a continuous deactivation trend during a 700 h time-on-stream run.Neither the leaching of active W nor the coking was responsible for the deactivation.Instead,XRD,HAADF-STEM and CO chemisorption results clearly showed the occurrence of significant aggregation of Pt particles,which caused a remarkable decrease of Pt-WOx interfacial sites.As a consequence,strong Br?nsted acid sites which were in situ formed by H2 dissociation at the Pt-WOx interfacial sites were reduced,leading to the deactivation of the catalyst.

Gene silencing:Double-stranded RNA mediated mRNA degradation and gene inactivation

The recent development of gene transfer approaches in plants and animals has revealed that transgene can undergo silencing after integration in the genome. Host genes can also be silenced as a consequence of the presence of a homologous transgene. More and more investigations have demonstrated that double- stranded RNA can silence genes by triggering degradation of homologous RNA in the cytoplasm and by directing methylation of homologous nuclear DNA sequences. Analyses of Arabidopsis mutants and plant viral suppressors of silencing are unraveling RNA-silencing mechanisms and are assessing the role of methy- lation in transcriptional and posttranscriptional gene silencing. This review will focus on double-stranded RNA mediated mRNA degradation and gene inactivation in plants.

励磁系统常见故障分析

对山西兴能发电有限责任公司机组的励磁系统故障报警、励磁变过流保护动作跳闸、励磁变差动保护动作发电机跳闸、发电机失磁解列等常见故障进行了分析,找出了故障原因,提出了防范措施。

Hospital without dyspnea： rationale and design of a multidisciplinary intervention

Dyspnea is a common and disabling symptom of respiratory and heart diseases, which is growing in incidence. During hospital admis- sion, breathlessness is under-diagnosed and under-treated, although there are treatments available for controlling the symptom. We have developed a tailored implementation strategy directed to medical staff to promote the application of these pharmacological and non-pharmacological tools in dealing with dyspnea. The primary aim is to decrease the rate of patients that do not receive an adequate relief of dyspnea. This is a four-stage quasi-experimental study. The intervention consists in two teaching talks that will be taught in Cardiology and Respiratory Medicine Departments. The contents will be prepared by Palliative Care specialists, based on available tools for management of dyspnea and patients＇ needs. A cross-sectional study of dyspnea in hospitalized patients will be performed before and after the intervention to ascertain an improvement in dyspnea intensity due to changes in medical practices. The last phase consists in the creation of consensus protocols for dyspnea management based in our experience. The results of this study are expected to be of great value and may change clinical practice in the near future and promote a changing for the better of dyspnea care.

FWK型装置及UFV-2F装置在大朝山电站的应用

大昆安全稳定控制系统主站装设在宝峰变,子站装设在大朝山,均采用FWK型分布式稳定控制装置。宝峰主站与大朝山子站之间采用两路微波通道交换数据和传送命令;同时采用与保护复用的载波命令通道向大朝山子站发送四个切机命令。当系统发生故障时,FWK装置根据检测到的故障元件与故障类型及事故前的电网运行方式,查找预先设置在装置内的策略表,采取在大朝山电站切机、减出力的措施,防止事故扩大,以确保电力系统的安全稳定运行。

A general solution and approximation for the diffusion of gas in a spherical coal sample

The square root relationship of gas release in the early stage of desorption is widely used to provide a simple and fast estimation of the lost gas in coal mines. However, questions arise as to how the relationship was theoretically derived, what are the assumptions and applicable conditions and how large the error will be. In this paper, the analytical solutions of gas concentration and fractional gas loss for the diffusion of gas in a spherical coal sample were given with detailed mathematical derivations based on the diffusion equation. The analytical solutions were approximated in case of small values of time and the error analyses associated with the approximation were also undertaken. The results indicate that the square root relationship of gas release is the first term of the approximation, and care must be taken in using the square root relationship as a significant error might be introduced with increase in the lost time and decrease in effective diameter of a spherical coal sample.

Natural Ageing Tests to Study In-service Different Facade Solutions--ETICS and Premixed One-Coat Rendered Walls

In situ testing provides accurate characterization of existing degradation mechanisms of materials and building systems which helps reducing the subjectivity of visual inspections especially when ageing under natural ageing conditions is carried out over significant periods of time. In this work, data collected from field experimental campaigns over 10 years after construction using several premixed one-coat rendered walls and over 4 and 6 years after construction in the case of ETICS （external thermal insulation composite systems） are presented and discussed. The influence of hydrophobic agents on the performance of both types of facades in terms of surface condition and water penetration was assessed by visual inspections, Karsten test and capillary tests. Additionally, adhesion tests and subsequent evaluation of porosity were also carried out for premixed one-coat mortars. The results obtained have shown that ageing of the rendering solutions, especially after 5 or 6 years in-service, results from the loss of resistance to liquid water penetration, especially at the surface. Yet, additional mechanisms such as leaching of hydrophobic agents and photochemical degradation are thought to be involved, too. Moreover, the results obtained using the Karsten test proved to be the most reliable method to determine the loss of water penetration resistance and predict the ageing of facade solutions. The information collected and the correlations established can help developing solutions to prevent early ageing and implement appropriate maintenance plans to delay their effect.

A simple theoretical approach for analysis of slide-toe-toppling failure

A prevalent kind of failure of rock slopes is toppling instability.In secondary toppling failures,these instabilities are stimulated through some external factors.A type of secondary toppling failure is"slide-toe-toppling failure".In this instability,the upper and toe parts of the slope have the potential of sliding and toppling failures,respectively.This failure has been investigated by an analytical method and experimental tests.In the present study,at first,the literature review of toppling failure is presented.Then a simple theoretical solution is suggested for evaluating this failure.The recommended method is compared with the approach of AMINI et al through a typical example and three physical models.The results indicate that the proposed method is in good agreement with the results of AMINI et al’s approach and experimental models.Therefore,this suggested methodology can be applied to examining the stability of slide-toe-toppling failure.

Analytical Model for Predicting the Heat Loss Effect on the Pyrolysis of Biomass Particles

This paper presents the combined influence of heat-loss and radiation on the pyrolysis of biomass particles by considering the structure of one-dimensional, laminar and steady state flame propagation in uniformly premixed wood particles. The assumed flame structure consists of a broad preheat-vaporization zone where the rate of gas-phase chemical reaction is small, a thin reaction zone composed of three regions: gas, tar and char combustion where convection and the vaporization rate of the fuel particles are small, and a broad convection zone. The analysis is performed in the asymptotic limit, where the value of the characteristic Zeldovich number is large and the equivalence ratio is larger than unity(i.e.u≥1). The principal attention is made on the determination of a non-linear burning velocity correlation. Consequently, the impacts of radiation, heat loss and particle size as the determining factors on the flame temperature and burning velocity of biomass particles are declared in this research.

Compound Chaijin Jieyu Tablets ameliorating insomnia complicated with depression by improving synaptic plasticity via regulating orexin A,melatonin,and acetylcholine contents

Objective To investigate the efficacy and mechanism of action of Compound Chaijin Jieyu Tablets(复方柴金解郁片,CCJJYT)in rats with insomnia complicated with depression.Methods Seventy-two Sprague-Dawley rats were randomly assigned into eight groups:the control,chronic unpredictable mild stress(CUMS),sleep deprivation(SD),CUMS+SD,positive drug(venlafaxine hydrochloride+diazepam),CCJJYT high-dose(CCJJYT˗2×),medium-dose(CCJJYT˗1×),and low-dose(CCJJYT˗0.5×)groups,with nine rats in each group.Depression-like behavior was evaluated by body weight,food intake,and behavioral tests such as the sucrose preference test(SPT),open field test(OFT),forced swimming test(FST),and pentobarbital-induced sleep test(PST).Hematoxylin-eosin(HE)staining and Golgi-Cox staining were used to observe changes in pathological tissue and synaptic morphology,respectively.Enzyme-linked immunosorbent assay(ELISA)was used to detect the contents of orexin-A and acetylcholine.The expression levels of orexin receptor 1(OXR1),melatonin receptor 1(MT1A),melatonin receptor 2(MT1B),acetylcholinesterase(AChE),and choline acetyltransferase(ChAT)were detected by immunohistochemistry and Western blot.Results In the present study,rats in the model group showed significant behavioral changes as well as a reduction in hippocampal dendritic branch length and synaptic number,along with increasing the content of orexin A and acetylcholine(P<0.05),and altered expression levels of OX1R,MT1A,MT1B,ChAT,and AChE in the hippocampus and prefrontal cortex after modeling(P<0.05).CCJJYT can improve depressive insomnia behavior and synaptic plasticity of rats(P<0.05),which is similar to that of the positive drug group.It can also decrease the content of orexin A and acetylcholine,and reduce the expression levels of OXR1 and ChAT in hippocampus and prefrontal cortex(P<0.05),and increase the expression levels of MT1A,MT1B,and AChE proteins(P<0.05).Conclusion CCJJYT has good antidepressant and insomnia effects,probably through the regulation of orexin-A,melatonin,and acetylcholine content in hippocampus and prefrontal cortex of rats,improving synaptic plasticity and thus exerting antidepressant and insomnia effects.

A new failure mechanism for deep cavity and upper bound solution of supporting pressure

The investigation of supporting pressure is of great significance to the design of underground structures.Based on the kinematical approach of limit analysis,an improved failure mechanism is proposed,and the supporting pressure is investigated for deep buried cavity.Three failure mechanisms are first introduced according to the existing failure mechanisms of geotechnical structures of limit analysis.A comparison with respect to the optimal failure mechanisms and the upper bound solutions provided among these three mechanisms are then conducted in an attempt to obtain the improved failure mechanism.The results provided by the improved failure mechanism are in good agreement with those by the existing method,the numerical solution and field monitoring,which demonstrates that the proposed failure mechanism is effective for the upper bound analysis of supporting pressure.

Multiresolution Fusion of Remote Sensing Images Based on Resolution Degradation Model

A new method based on resolution degradation model is proposed to improve both spatial and spectral quality of the synthetic images. Some ETM+ panchromatic and multispectral images are used to assess the new method. Its spatial and spectral effects are evaluated by qualitative and quantitative measures and the results are compared with those of IHS, PCA, Brovey, OWT(Orthogonal Wavelet Transform) and RWT(Redundant Wavelet Transform). The results show that the new method can keep almost the same spatial resolution as the panchromatic images, and the spectral effect of the new method is as good as those of wavelet-based methods.

Evaluation of an ＂Attract and Kill＂ System to Combat Ceratitis capitata on Peach Trees in Tunisia

Attract and kill （AK） technology was evaluated against the Mediterranean fruit fly （Med-fly）, Ceratitis capitata W.. Treatment was carried out in two peach orchards of four hectares each; first one located in Borj-Touil and the second in El-Kssibi Mornag, Northern Tunisia during the 2012 field season. AK is a specialized system based on hydrolyzed proteins and alpha-cypermethrin. During this study, 400 AK bait stations were placed in every hectare, four weeks before fruits color changes. The tested AK system was found effective in reducing the number of C. capitata population to 70% comparing to the untreated orchards. Fruit damages assessment showed significant differences between treatments in respect of decreasing infestation onto fruits Study results indicated that AK baited treatments were able to reduce dropped and soften fruits infestation seven times than that of control plots. Fruit damages were restricted to 4%-5% in treated areas with AK system in compare to 31%-35% recorded in control plots. This novel AK system showed good performance to combat Med-fly and can successfully used to combat various fruit fly species when applied for an area wide application program.