热力学第二定律的统计实质

用统计力学的观点，探讨了熵的统计意义及热力学第二定律的统计实质。

传送带模型中“功能关系”与“能量守恒”的对比分析

计算传送带因载物而多消耗的电能,即多做的功时,可以依据能量守恒定律或功能关系求解.从能量守恒的角度思考,等于物块机械能的增加量与系统内能增加量之和,但从功能关系的角度处理,等于哪个力多做的功呢？本文在对比＂滑块-木板＂模型的基础上,针对传送带空载与负载两种状态进行受力分析,一定程度上回答了这个问题.

Study on the Effect of Simvastatin on Left Ventricular Mass and Endothelial Function and the Relationship between Their Changes in the Patients with Essential Hypertension

Objective:To study the effect of Simvastatin on the left ventricular mass and endothelial function and to investigate the relationship between their changes in the patients with essential hypertension(EH). Methods: 50 patients with hypertension without severe complication were divided into two groups in a randomized,controlled and single blind trial.Group I(n=25)were given Simvastatin and hydragogue for 12 weeks while Group Ⅱ were given hydragogue during the same time.We detected the left ventricular mass and the brachial artery dilatation induced by reactive hyperemia(DIRH)or nitroglycerin(DING)respectively with ultrasonography in all patients before and after treatment.25 normal subjects without any treatment were taken as the control. Results:The left ventricular mass index(LVMI)was higher in the two groups of patients[(133.61±31.02)g/m 2;(118.04±39.62)g/m 2]than that in the control(88.79±22.73)g/m 2 before treatment(P<0.01,0.000 1,respectively)while the blood pressure was higher.The DIRH was lower in the two groups of patients(5.93±2.24)%;(6.54±3.16)%than that in the control(13.09±2.99)%,P<0.000 1.There was no significantly differences in age,serum concentrations of total cholesterol,triglyceride,sugar,blood pressure or the DING between two groups of patients and the control(P>0.05).And there was no significant difference in the all variables between group Ⅰ and group Ⅱ before treatment.After treatment the LVMI decreased[(133.61±31.02)g/m 2 VS(91.07±16.01)g/m 2,P<0.01]and the DTRH increased[(5.93±2.24)% VS(13.53±2.38)%,P<0.01]in the patients of group Ⅰ while there was no significant change in LVMI and DIRH in the patients of group Ⅱ.The blood pressure in the two groups of patients was decreased to the normal.Compared with group Ⅱ,the changes of LVMI and DIRH was higher in patients of group Ⅰ though the serum concentrations of total cholesterol,triglyceride or sugar were not significantly different.No significant change in serum concentrations oftotal cholesterol,triglyceride or sugar was found during treatment in the two groups of patients.Analysis showed that the LVMI correlated with DIRH and the change of LVMI correlated better with the change of DIRH(r=-0.56;0.69,P<0.000 1,respectly). Conclusions: The increase of left ventricular mass was related with endothelial dysfunction in essential hypertension.Being independent of the changes of serum concentrations of total cholesterol,triglyceride or sugar and blood pressure,Simvastatin could inhibit the increase of left ventricular mass and improve endothelial function.

Effect of lactobacillus on the gut microflora and barrier function of the rats with abdominal infection

AIM:To investigate the effect of probiotics supplemented by gut on the tight junctions of epithelial cells, barrier function and the microflora of rats with abdominal infection. METHODS: After the model of cecal ligation and perforation established, SD rats were divided into two groups: parenteral nutrition (PN) group and PIM+probiotics (probiotics) group, PN solution was supplemented by neck vein and probiotics was delivered via the jejunostomy tube for five days. Vena cava blood and the homogenated tissue of liver, lung and mesenteric lymph nodes were cultured to determine the bacterial translocation rate (BTR). The ultra-structure of epithelial tight junctions and microvilli of the gut were observed by electron microscopy; occluding expression was measured by indirect-immune fluorescence method; anaerobic bacterial growth by anaerobic culture and DNA fingerprint of bacterial colonies of the feces by PCR. RESULTS: The quantity of lactobacteria and bifydobacteria in probiotics group was higher than that of PN group. The profiles of DNA fingerprint expression in probiotics group were similar to that in the normal group, a new 16S rDNA sequence appeared in the profile in PN group. The occludin expression, the integrality of the gut epithelial tight junction and microvilli in probiotics group were improved as compared with PN group. The BTR and endotoxin in blood were reduced more significantly in probiotics group as compared with PN group. CONCLUSION: The probiotics could improve the gut microflora disturbance, increase occludin expression, maintain the gut epithelial tight junction and decrease the bacterial translocations rate.

Relationship between perioperative glycemic control and postoperative infections

Perioperative hyperglycemia in critically ill surgery patients increases the risk of postoperative infection (POI), which is a common, and often costly, surgical complication. Hyperglycemia is associated with abnormalities in leukocyte function, including granulocyte adherence, impaired phagocytosis, delayed chemotaxis, and depressed bactericidal capacity. These leukocyte deficiencies are the cause ofinfection and improve with tight glycemic control, which leads to fewer POIs in critically ill surgical patients. Tight glycemic control, such as intensive insulin therapy, has a risk of hypoglycemia. In addition, the optimal targeted blood glucose range to reduce POI remains unknown. Since 2006, we have investigated tight perioperative blood glucose control using a closed-loop artificial endocrine pancreas system, to reduce POI and to avoid hypoglycemia. In this Topic Highlight, we review the relationship between perioperative glycemic control and POI, including the use of the artificial pancreas.

Precipitation Pulses and Soil CO_2 Emission in Desert Shrubland of Artemisia ordosica on the Ordos Plateau of Inner Mongolia,China

Precipitation is the major driver of ecosystem functions and processes in semiarid and arid regions. In such waterlimited ecosystems, pulsed water inputs directly control the belowground processes through a series of soil drying and rewetting cycles. To investigate the effects of sporadic addition of water on soil CO2 effux, an artificial precipitation event （3 mm） was applied to a desert shrub ecosystem in the Mu Us Sand Land of the Ordos Plateau in China. Soil respiration rate increased 2.8 4.1 times immediately after adding water in the field, and then it returned to background level within 48 h. During the experiment, soil CO2 production was between 2 047.0 and 7 383.0 mg m^-2. In the shrubland, soil respiration responses showed spatial variations, having stronger pulse effects beneath the shrubs than in the interplant spaces. The spatial variation of the soil respiration responses was closely related with the heterogeneity of soil substrate availability. Apart from precipitation, soil organic carbon and total nitrogen pool were also identified as determinants of soil CO2 loss in desert ecosystems.

Spleen:A new role ffoorr an old player?

The spleen could be considered a neglected organ.To date,it has been deemed an ancillary organ in portal hypertension or an organ localization in lymphoproliferative diseases,even though it has had significant attention in infectious diseases for some time.Now,it is thought to be central in regulating the immune system,a metabolic asset and involved in endocrine function with regard to nonalcoholic fatty liver disease.The main mechanisms involved in this complex network will be critically discussed in this article.

Dynamic spectrum allocations in multi-cells and intra-cell of cognitive network to enhance system performance

In this study, we propose new dynamic spectrum allocations in multi-cells and intra-cell of cognitive network to enhance system performance in terms of decreasing probability of interruption and spectrum handoff of communication services in a cognitive system. The inter-cells of the spectrum allocation mechanism is designed to share the risk of vacating spectrum caused by licensed incumbents re-occupying the spectrum and minimize probability of service interruption in the cognitive network. This mechanism also can guarantee fairness among multi-cells. The intra-cell of the proposed spectrum allocation is based on a service data hierarchical model and establishes a mapping mechanism between layered data and the spectrum. It can reduce probability of spectrum handoff. Finally, simulation results are given and show that the new mechanism can reduce service interruption ratio and the probability of spectrum handoff caused by licensed incumbents with re-occupying the spectrum.

Utilisation of Geothermal Heat Pumps within Permeable Pavements for Sustainable Energy and Water Practices

Geothermal heat pumps （GHPs） are an attractive proposition for renewable energy worldwide as it uses energy naturally stored in the earth. The Earth is a very resourceful form of energy, using the natural solar energy collection and heat storage capabilities as an infinite heat source/heat sink at the base of permeable pavements, which can provide excellent temperature gradients for GHP＇s. Experimental rigs were setup up at The University of Edinbttrgh for a combined permeable pavement and GHP system. At the base of a pavement structure （approximately 1 meter） below the ground＇s surface, temperatures are constant of 10℃ in the U.K all year round. The GHP performance efficiency was analysed by the coefficient of performance （COP） in a heating cycle and the energy efficiency ratio （EER） in a cooling cycle. The mean COP and EER for both systems averaged between 2-4.5 and 3-5 respectively. The combined GHP and pavement structure operated at an optimum efficiency for both heating and cooling cycles and has shown to be unaffected by higher summer or lower winter temperatures. This hybrid system is an attractive renewable energy technology and has additional environmental benefits such as urban runoff reuse and recycling.

Design and Implementation of Power Line Communication Module for Network Household Appliance

This paper presents the basic principle of OFDM technology and some key technologies, and do the simulation of OFDM technology. Secondly, on the basis of the design of intelligent Home Furnishing system demand, this paper research and design low voltage power line carrier communication based on Intelligent Home Furnishing system for. The circuit takes ARM Cortex-M3 based on the ARM kernel as the central controller, and realize remote monitoring and control of equipment through the transplantation of uC/OS-II system and the design of Web Serve program. Using OFDM power line carrier communication modes as networking mode of the intelligent Home Furnishing system. Finally, the paper realize the intelligent node and relevant software that constitute a complete system of intelligent Home Furnishing.

考虑吸附作用的各向异性煤体有效应力

基于Carroll的各向异性孔隙介质有效应力公式,引入吸附气体相的影响,推导了考虑界面吸附作用的各向异性介质有效应力表达式;根据界面热力学的基本理论,在考察固相、气相、界面吸附相及系统能量方程基础上,分析了固相应力与孔隙压力及表面势的关系,推导了吸附作用影响下固相体积压缩系数的表达式;依据羊渠河矿煤样的试验数据,计算了不同气体压力条件下的固相体积压缩系数,计算结果表明:吸附作用使得固相压缩变形和煤体有效应力减小,在孔隙压力较低时吸附作用效应更加显著.

Performance analysis of visual markers for indoor navigation systems

The massive diffusion of smartphones, the growing interest in wearable devices and the Internet of Things, and the exponential rise of location based services（LBSs） have made the problem of localization and navigation inside buildings one of the most important technological challenges of recent years. Indoor positioning systems have a huge market in the retail sector and contextual advertising; in addition, they can be fundamental to increasing the quality of life for citizens if deployed inside public buildings such as hospitals, airports, and museums.Sometimes, in emergency situations, they can make the difference between life and death. Various approaches have been proposed in the literature. Recently, thanks to the high performance of smartphones＇ cameras, marker-less and marker-based computer vision approaches have been investigated. In a previous paper, we proposed a technique for indoor localization and navigation using both Bluetooth low energy（BLE） and a 2D visual marker system deployed into the floor. In this paper, we presented a qualitative performance evaluation of three 2D visual markers, Vuforia,Ar Uco marker, and AprilT ag, which are suitable for real-time applications. Our analysis focused on specific case study of visual markers placed onto the tiles, to improve the efficiency of our indoor localization and navigation approach by choosing the best visual marker system.

Leptin in normal physiology and leptin resistance

Since the discovery of leptin as an adipokine in 1994, much progress has been made in the research about leptin. Circulating leptin binds to leptin receptor, activates STAT3-dependent and STAT3-independent signaling pathways, and plays an effective role in energy home- ostasis, neuroendocrine function and metabolism mainly through acting on the central nervous system, especially the hypothalamus. Leptin resistance is considered as a key risk factor for obesity. Various mechanisms have been formu- lated in order to explain leptin resistance, including impairment in leptin transport, attenuation in leptin sig- naling, ER stress, inflammation and deficiency in autop- hagy. Here, we review our current knowledge about leptin action, leptin signaling and leptin resistance, hoping to provide new ideas for the battle against obesity.

Fluid dynamic modeling of junctions in internal combustion engine inlet and exhaust systems

The modeling of inlet and exhaust systems of internal combustion engine is very important in order to evaluate the engine performance.This paper presents new pressure losses models which can be included in a one dimensional engine simulation code.In a first part,a CFD analysis is made in order to show the importance of the density in the modeling approach.Then,the CFD code is used,as a numerical test bench,for the pressure losses models development.These coefficients depend on the geometrical characteristics of the junction and an experimental validation is made with the use of a shock tube test bench.All the models are then included in the engine simulation code of the laboratory.The numerical calculation of unsteady compressible flow,in each pipe of the inlet and exhaust systems,is made and the calculated engine torque is compared with experimental measurements.

Time-varying Performance Prediction and System Identification of Internal Combustion Engines

Design for life-time performance and proper maintenance measures are usually needed to prolong the mean-time-between-failures of complex equipments such as internal combustion engines.To reach this,it is important to obtain the information of time-varying system performance in design stage and to identify the structural change at each moment.So a multidisciplinary model based method is studied in this paper to unify the time-varying performance(TVP) prediction and system identification(SI) of equipments.The related multidisciplinary model in this paper should be not only precise to give simulation results but also sensitive to the variation of system parameters.So the varying history of system performance along with the structural change can be obtained from the model.Then the value of system parameters can be identified by seeking roots with given detected responding data and relationship between system responding data and system parameters.A case study on a low power gasoline engine shows that the method presented in this paper can provide useful information for the development and maintenance of complex equipments.