论如何做好大型化工项目外管系统

随着化工装置生产规模越来越趋于大型化,外管系统的工作量及复杂程度也越来越大,并且经常会出现多家设计院共同完成一个大型项目的情况。本文对如何做好大型项目的外管系统进行了详细梳理。

通信运营商带外网管系统剖析

带外网管是通过专门的网管通道实现对网络的管理,将网管数据与业务数据分开,为网管数据建立独立通道,这样可以保证重要管理数据、敏感的统计信息、占用带宽的实时计费信息在同一个网络中进行安全、可靠的传输,带外管理方式有助于提高网管的效率与可靠性,也有利于提高网管数据的安全性。

Design and realization of security physical isolation system

A physical isolation system based on PCI (peripheral component interconnect),embedded with intelligence card technology, strong identity authentication technology and securityaudit, etc., is introduced. The system can physically isolate the internaland external networks. Thehardware of the system, including PCI interface control circuits, network interface circuits andlogic control circuits, is designed to automatically adapt its operation speed and mode to thenetwork and securely isolate the internal and external networks; the software of the system,including the security strategy management module, the security audit module, the database recordexchanging module, the file exchanging module and the mail exchanging module, is designed toefficiently exchange and manage the data transference between the internal and external networks.Also the driver of the system is implemented with Windows driver development kits (DDK) based onNetwork Driver Interface Specification (NDIS). The prototype ofthe system developed has beenemployed in the Police Fire Protection Bureau of Hubei Province, which performs consistently andefficiently. The technological cruxes discussed have practical values for related subjects.

The Intelligent Management System Of Campus Express In Tianjin

Courier services develop fast as e-commerce advances but challenged by the problem of ＂the last kilometer＂. The research analyzed problems of courier ser- vices in universities or colleges with a case study of universities in Tianjin and pro- posed suggestions on intelligent courier services.

Characterization of foreign grain on 6H-SiC facet

6H-SiC single crystals were grown by sublimation method. It is found that foreign grains occur frequently on the facets of the crystals. To characterize the foreign grain, a longitudinal and a sectional cut samples were prepared by standard mechanical processing method. Raman spectrum confirms that the foreign grain is actually a mis-oriented 6H-SiC grain. The surface structure of the foreign grain was studied by chemical etching and optical microscopy. It is shown that etch pits in foreign grain region take the shape of isosceles triangle, which are different from those in mono-crystalline region, and high density stacking faults are observed on the surface of the foreign grain. The orientation of foreign grain surface is determined to be （10]-4） plane by back-scattering X-ray Laue image. The X-ray powder diffraction reveals that the powder is partly graphitized after a long crystal growth rim. Therefore it is believed that the loss of Si results in the formation of C inclusions, which is responsible for the nucleation of foreign grain in the facet region.

In vitro effect of pantoprazole on lower esophageal sphincter tone in rats

AIM:To investigate the in vitro effects of pantoprazole on rat lower esophageal sphincter(LES)tone.METHODS:Rats weighing 250-300 g,provided by the Yeditepe University Experimental Research Center(Yü-DETAM),were used throughout the study.They were anesthetized before decapitation.LES tissues whose mucosal lining were removed were placed in a stan-dard 30-mL organ bath with a modif ied Krebs solution and continuously aerated with 95% oxygen-5% carbon dioxide gas mixture and kept at room temperature.The tissues were allowed to stabilize for 60 min.Sub-sequently,the contractile response to 10-6 mol/L carba-chol was obtained.Different concentrations of freshly prepared pantoprazole were added directly to the tis-sue bath to generate cumulative concentrations of 5×10-6 mol/L,5×10-5 mol/L,and 1.5×10-4 mol/L.Activi-ties were recorded on an online computer via a 4-channeltransducer data acquisition system using the software BSL PRO v 3.7,which also analyzed the data.RESULTS:Pantoprazole at 5×10-6 mol/L caused a small,but statistically insignif icant,relaxation in the car-bachol-contracted LES(2.23% vs 3.95%).The 5×10-5 mol/L concentration,however,caused a signif icant relax-ation of 10.47% compared with the control.1.5×10-4 mol/L concentration of pantoprazol caused a 19.89% relaxation in the carbachol contracted LES(P<0.001).CONCLUSION:This is the fi rst study to demonstrate that pantoprazole has a relaxing effect in isolated LESs.These results might have signif icant clinical implications for the subset of patients using proton pump inhibitors who do not receive full symptomatic alleviation from gastroesophageal reflux disease.

The use of suicide gene systems in vascular cells in vitro

To investigate the efficiency of suicide gene systems on vascular cells, HSV-tk/GCV and EC-CD/5-FC systems were established on vascular endothelial cells in vitro by retroviral transduction. Both modified cell lines were highly sensitive to prodrugs, the IC50 for GCV was less than 0.4 μM, and IC50 for 5-FC was less than 75 μM,while the parental endothelial cells were insensitive even at the highest concentrations of prodrugs in this experiment. Mixed cellular assay showed that significant bystander effect was exhibited in modified endothelial cells.When only 10% or 30% of the mixed cells were tk positive and exposed to 20 μM GCV for 6 days, more than 60% or 90% of the whole population was killed. Similar result was also found in CD positive cells. These results indicated that both HSV-tk/GCV and EC-CD/5-FC systems could efficiently suppress endothelial cell growth in vitro.

Diagnosis of Soil Nutrient Constraints in Small-Scale Groundnut （Arachis hyopaea L,） Production Systems of Western Kenya Using Infrared Spectroscopy

Wise decision-making on resource allocation and intervention targeting for soil management cannot rely solely on trial and error methods and field observations used by small-scale farmers： cost-effective soil fertility survey methods are needed. This study aimed to test the applicability of infrared spectroscopy （IR） as a diagnostic screening tool for making soil fertility recommendations in small-scale production systems. Soil fertility survey of 150 small-scale groundnut farms in western Kenya was conducted using a spatially stratified random sampling strategy. Soil properties examined were pH in water （pHw）, total carbon （C）, total nitrogen （N）, extractable phosphorus （P）, exchangeable potassium （K）, calcium （Ca）, magnesium （Mg） and texture. These properties were calibrated to mid-infrared （MIR） diffuse reflectance using partial least square regression （PLSR）. Cross-validated coefficient of determination （r2） values obtained from calibration models were 〉 0.80 for all properties, except P and K with 0.66 and 0.50 respectively. Soil nutritional deficiencies were evaluated using critical nutrient limits based on IR predictions and composite soil fertility indices （SFIs） developed from the soil properties using principal component analysis. The SFIs were calibrated to MIR soil spectral reflectance with cross-validated r： values 〉 0.80. The survey showed that 56% of the groundnut farms had severe soil nutrient constraints for production, especially exchangeable Ca, available P and organic matter. IR can provide a robust tool for farm soil fertility assessment and recommendation systems when backed up by conventional reference analyses. However, further work is required to test direct calibration of crop responses to spectral indicators and to improve prediction of extractable P and K tests.

Thoughts on e-waste recycling

This paper summarizes the situation of e-waste recycling in China, points out several key problems, identify the causes and draw lessons and experiences abroad about e-waste management, propose systematic suggestions from the production side, the recovery side, consumers side, government departments and thelegislation.

Reviews of the research on water resources management system at home and abroad

The reform of the system of water resource management abroad has started since the 50s of last century, it has left us a lot of experiences in many aspects with the innovation of system, such as the legal environment in water resources, water rights, water market theory, and the ＂participation＂ management of water resources, these experiences has been promoted in more than 40 developing countries. Based on analyzing the theory and experiences of water resources management both at home and abroad, especially the theory and experiences of agricultural water resources management, this paper puts forward the main problems waiting for further investigation in China＇s water resources management and provides some reference and inspiration for the innovation of the system of water resource management in China.

Vibrational characteristics of piping system in air conditioning outdoor unit

The modal analysis of piping system in air conditioner (AC) outdoor unit is essential to investigate the vibration properties of the system. In view of the growing significance of numerical finite element (FE) model for vibration behaviour prediction, the AC piping elastic end support characterization has been explored. The axial and radial stiffness variables (ka, kr1, kr2) of the compressor-piping mounting are obtained and represented by dynamic stiffness of compressor grommet. They are obtained from dynamic load deflection test based on compressor operating condition such as excitation frequency and amplitude. The unknown stiffness variables of the other tube end (chassis-piping mounting) are determined by parameter fine tuning. An experimental modal analysis using impact hammer test has also been employed to determine the vibration properties such as natural frequencies, mode shapes and damping ratio of the piping structures. The modal parameters acquisition using SCADAS mobile acquisition system and LMS Impact Testing software is compared with the corresponding simulated modal properties using Abaqus. Most of the simulated natural frequencies achieve good correlation with the measured frequencies and it is reasonably a good prediction model to predict vibration behaviour of AC piping structures.