加强型Q460C方钢管间隙N型节点承载力研究

为考察加强构造对N型节点失效机理和承载力的影响规律,对加强节点和基本节点进行了主管轴压静力加载试验,试验结果表明:基本节点的破坏模式为主管上翼缘受拉鼓曲开裂,加强节点破坏模式为加劲板屈曲和覆板焊缝受拉开裂;加强节点的承载力较基本节点提高了9.4%~36.5%;增加覆板厚度,可明显提高节点承载力。采用ABAQUS软件对覆板和加劲板加强的Q460C方钢管间隙N型节点进行了有限元参数研究,考察了主管宽厚比γ、主支管厚度比η、主支管宽度比β、受拉支管与主管夹角θ、支管间距与主管宽度比ξ对节点破坏模式、应力分布、主管荷载-位移曲线和覆板焊缝断裂指数I f的影响规律。根据试验和数值模拟结果,提出了覆板和加劲板加强的Q460C方钢管间隙N型节点承载力计算式和构造设计建议。

Effects of N Management on Yield and N Uptake of Rice in Central China

Efficient N fertilizer management is critical for the economic production of rice and the long-term protection of environmental quality. A field experiment was designed to study the effects of N fertilizer management practices on grain yield and N uptake office. The experiment was laid out in the randomized complete block design with four replications in Central China during 2008 and 2009. Five N treatments denoted as No, NIsoA, N15oB, N24OA, and N24oB, respectively, were studied. NO represented no N application and served as a control, N15OA and N15oB indicated the total N application of 150 kg N ha-I but with two different application schedules （A and B） across the early stage of rice growth. Schedule A was applied as follows： 40% basal, 30% at 10 d after transplanting （DAT） and 30% at 36 DAT （nearly at the panicle initiation stage）, while schedule B was as follows： 30% at basal, 20% at 10 DAT, and 50% at 36 DAT. Similarly, N240A and N240B indicated the total N application of 240 kg N ha-1 with schedules A and B as described above. To quantify N uptake from fertilizer and soil, a 15N experiment was also conducted within the main experimental field, with micro-plots. Grain yields were significantly increased as N rates increased from 0 to 240 kg N ha-1. At the same rate, splitting N application as schedule B significantly increased the grain yield, spikelets per panicle, percentage of ripened grain, and 1 000-grain weight, compared with the N application according to schedule A. Mean rice recovery of N fertilizer by ~SN tracing method ranged from 25.39% at N24oA to 34.89% at NIsoB, however, N fertilizer residual rate in the soil ranged from 12.40% at N240A to 16.61% at N^s0w About 31.5 and 28.5% of total uptake of ~SN derived from basal fertilizer was absorbed at panicle initiation and heading stages, respectively. However, 65.6-92.5% of total uptake of 15N derived from topdressing fertilizer was absorbed at the heading stage. Based on yield and nitrogen recovery efficiency, splitting N application according to schedule B at the rate of 240 kg N ha-1 will be more profitable among the tested five N treatments in Central China.

Effects of cotton field management practices on soil CO2 emission and C balance in an arid region of Northwest China

Changes in both soil organic C storage and soil respiration in farmland ecosystems may affect atmospheric CO2 concentration and global C cycle. The objective of this field experiment was to study the effects of three crop field management practices on soil CO2 emission and C balance in a cotton field in an arid region of Northwest China. The three management practices were irrigation methods（drip and flood）, stubble managements（stubble-incorporated and stubble-removed） and fertilizer amendments（no fertilizer（CK）, chicken manure（OM）, inorganic N, P and K fertilizer（NPK）, and inorganic fertilizer plus chicken manure（NPK＋OM））. The results showed that within the C pool range, soil CO2 emission during the whole growing season was higher in the drip irrigation treatment than in the corresponding flood irrigation treatment, while soil organic C concentration was larger in the flood irrigation treatment than in the corresponding drip irrigation treatment. Furthermore, soil CO2 emission and organic C concentration were all higher in the stubble-incorporated treatment than in the corresponding stubble-removed treatment, and larger in the NPK＋OM treatment than in the other three fertilizer amendments within the C pool range. The combination of flood irrigation, stubble incorporation and application of either NPK＋OM or OM increased soil organic C concentration in the 0-60 cm soil depth. Calculation of net ecosystem productivity（NEP） under different management practices indicated that the combination of drip irrigation, stubble incorporation and NPK＋OM increased the size of the C pool most, followed by the combination of drip irrigation, stubble incorporation and NPK. In conclusion, management practices have significant impacts on soil CO2 emission, organic C concentration and C balance in cotton fields. Consequently, appropriate management practices, such as the combination of drip irrigation, stubble incorporation, and either NPK＋OM or NPK could increase soil C storage in cotton fields of Northwest China.

Effects of Nitrogen Management on the Yield of Winter Wheat in Cold Area of Northeastern China

A plot experiment including four treatments, CK （N 105 kg ha-1 as urea, including a basal N application of 35 kg ha-I and a topdressing N 70 kg ha-1 at turned green stage） and optimized N management （OPT1, OPT2 and OPT3, applied two-thirds, one-third and two-fifths N at jointing stage, respectively, total N 60 kg ha-l）, was conducted to evaluate the effects of nitrogen management on growth and N uptake of winter wheat （Triticum aestivum）, Dongnong 1, which is the first highly cold tolerant winter wheat in China. Index of population quality, N uptake and yield were determined. The ear-bearing tiller rate was increased by above 12%, and the leaf area index, biomass and N uptake were significantly decreased （P〈O.05） at jointing stage. OPT treatments increased the grain to leaf area ratio at heading stage, the dry matter weight and N uptake after heading by 14.3-27.9%, 11.6-28.7% and 118.1-161.8 %, respectively. The yield of the OPT treatments was increased by 14.2-37.5% compared with CK, and there was a significant difference （P〈0.05） between CK and OPT1 treatments. Harvest index and N partial factor productivity （PFP, kg grain yield per kg N applied） was clearly enhanced from 0.4 and 35.6 kg, respectively for CK to an average of 0.48 （P〈0.05） and 77.6 kg （P〈0.05） in the OPT treatments. These results indicated that the optimized N management increased the harvest index, yield and N use efficiency by decreasing the N application rate and postponing N application time, improved wheat population quality, controlled excessive growth in the vegetative stages and increased dry matter and N accumulation rates after heading.

Effects of Site-Specific Nitrogen Management on Yield and Dry Matter Accumulation of Rice from Cold Areas of Northeastern China

The effects of yield increase and mechanism of site-specific nitrogen management （SSNM） in five rice varieties from cold areas of northeastern China were studied. Plot experiment for critical SPAD value and experiments of two fertilization methods, SSNM and farmer＇s fertilization practice （FFP） were conducted to study their effects on the quality and dry matter accumulation of rice population, as well as N uptake. Compared with FFP, SSNM significantly decreased the average N rate by 33.8%, significantly increased average ear-bearing tiller rate and LAI for grain-filling stage by 12.3% and 14.1-27.6%, correspondingly, improved dry matter weight and N uptake after heading period by 4.3-29.1% and 11.8-55.1% （P 〈 0.05）, and heightened recovery efficiency and agronomic efficiency by 38.5-133.4% （P 〈 0.05） and 39.8-194.3% （P 〈 0.05）, respectively, as well as increased the average yield by 9.8% in 2004 and 2005. The results indicated that the accumulation rate of dry matter and N increased the rice yield and N use efficiency, because of improving rice population quality and increasing LAI after heading period.

Long-Term Impact of Soil Management on Microbial Biomass C, N and P in Rice-Based Cropping System

A 12-year field experiment was conducted to investigate the effect of different tillage methods and fertil- ization systems on microbial biomass C, N and P of a gray fluvo-aguic soil in rice-based cropping system. Five fertilization treatments were designed under conventional tillage (CT) or no tillage (NT) system: no fertilizer (CK); chemical fertilizer only (CF); combining chemical fertilizer with pig manure (PM); combining chemical fertilizer with crop straw (CS) and fallow (F). The results showed that biomass C, N and P were enriched in the surface layer of no-tilled soil, whereas they distributed relatively evenly in the tilled soil, which might result from enrichment of crop residue, organic manure and mineral fertilizer, and surficial development of root systems under NT. Under the cultivation system, NT had slightly greater biomass C, N and P at 0～5 cm depth, significantly less biomass C, N and P at 5～15 cm depth, less microbial biomass C, N and equivalent biomass P at 15 ～30 cm depth as compared to CT, indicating that tillage was beneficial for the multiplica tion of organisms in the plowed layer of soil. Under the fallow system, biomass C, N and P in the surface layer were significantly greater for NT than CT while their differences between the two tillage methods were negligible in the deeper layers. In the surface layer, biomass C, N and P in the soils amended with organic manure combined with mineral fertilizers were significantly greater than those of the treatments only with mineral fertilizers and the control. Soils without fertilizer had the least biomass nutrient contents among the five fertilization treatments. Obviously, the long-term application of organic manure could maintain the higher activity of microorganisms in soils. The amounts of biomass C, N and P in the fallowed soils varied with the tillage methods; they were much greater under NT than under CT, especially in the surface layer, suggesting that the frequent plowing could decrease the content of organic matter in the surface layer of the fallowed soil.

Hepatitis C and kidney disease:An overview and approach to management

Hepatitis C infection and chronic kidney disease are major health burden worldwide. Hepatitis C infection is associated with a wide range of extra-hepatic manifestations in various organs including the kidneys. A strong association between hepatitis C and chronickidney disease has come to light. Hemodialysis in supporting the end stage renal disease patients unfortunately carries a risk for hepatitis C infection. Despite much improvement in the care of this group of patients,the prevalence of hepatitis C infection in hemodialysis patients is still higher than the general population. Hepatitis C infection has a negative effect on the survival of hemodialysis and renal transplant patients. Treatment of hepatitis C in end stage renal disease patients using conventional or pegylated interferon with or without ribavirin remains a clinical challenge with low response rate,high dropout rate due to poor tolerability and many unmet needs. The approval of new direct acting antiviral agents for hepatitis C may dramatically change the treatment approach in hepatitis C infected patients with mild to moderate renal impairment. However it remains to be confirmed if the newer Hepatitis C therapies are safe in individuals with severe renal impairment. This review article discusses the relationship between hepatitis C and chronic kidney disease,describe the various types of renal diseases associated with hepatitis C and the newer as well as the existing treatments for hepatitis C in the context of this subpopulation of hepatitis C patients.

Diagnosis and management of interstitial pneumonitis associated with interferon therapy for chronic hepatitis C

Interstitial pneumonitis(IP) is an uncommon pulmonary complication associated with interferon(IFN) therapy for chronic hepatitis C virus(HCV) infection.Pneumonitis can occur at any stage of HCV treatment,ranging from 2 to 48 wk,usually in the first 12 wk.Its most common symptoms are dyspnoea,dry cough,fever,fatigue,arthralgia or myalgia,and anorexia,which are reversible in most cases after cessation of IFN therapy with a mean subsequent recovery time of 7.5 wk.Bronchoalveolar lavage in combination with chest high resolution computed tomography has a high diagnostic value.Prompt discontinuation of medication is the cornerstone,and corticosteroid therapy may not be essential for patients with mild-moderate pulmonary functional impairment.The severity of pulmonary injury is associated with the rapid development of IP.We suggest that methylprednisolone pulse therapy followed by low dose prednisolone for a short term is necessary to minimize the risk of fatal pulmonary damage if signs of significant pulmonary toxicity occur in earlier stage.Clinicians should be aware of the potential pulmonary complication related to the drug,so that an early and opportune diagnosis can be made.

Landslide susceptibility zonation method based on C5.0 decision tree and K-means cluster algorithms to improve the efficiency of risk management

Machine learning algorithms are an important measure with which to perform landslide susceptibility assessments, but most studies use GIS-based classification methods to conduct susceptibility zonation.This study presents a machine learning approach based on the C5.0 decision tree(DT) model and the K-means cluster algorithm to produce a regional landslide susceptibility map. Yanchang County, a typical landslide-prone area located in northwestern China, was taken as the area of interest to introduce the proposed application procedure. A landslide inventory containing 82 landslides was prepared and subsequently randomly partitioned into two subsets: training data(70% landslide pixels) and validation data(30% landslide pixels). Fourteen landslide influencing factors were considered in the input dataset and were used to calculate the landslide occurrence probability based on the C5.0 decision tree model.Susceptibility zonation was implemented according to the cut-off values calculated by the K-means cluster algorithm. The validation results of the model performance analysis showed that the AUC(area under the receiver operating characteristic(ROC) curve) of the proposed model was the highest, reaching 0.88,compared with traditional models(support vector machine(SVM) = 0.85, Bayesian network(BN) = 0.81,frequency ratio(FR) = 0.75, weight of evidence(WOE) = 0.76). The landslide frequency ratio and frequency density of the high susceptibility zones were 6.76/km^(2) and 0.88/km^(2), respectively, which were much higher than those of the low susceptibility zones. The top 20% interval of landslide occurrence probability contained 89% of the historical landslides but only accounted for 10.3% of the total area.Our results indicate that the distribution of high susceptibility zones was more focused without containing more " stable" pixels. Therefore, the obtained susceptibility map is suitable for application to landslide risk management practices.

Short Response of Spring Wheat to Tillage, Residue Management and Split Nitrogen Application in a Rice-Wheat System

A ifeld experiment was conducted to study the impact of tillage, crop residue management and nitrogen （N） splitting on spring wheat （Triticum aestivum L.） yield over 2 yr （2010-2012） in a rice （Oryza sativa L.）-wheat system in northwestern Pakistan. The experiment was conducted as split plot arranged in randomized complete blocks design with three replications. Treatments comprised six tillage and residue managements：zero tillage straw retained （ZTsr）, zero tillage straw burnt （ZTsb）, reduced tillage straw incorporated （RTsi）, reduced tillage straw burnt （RTsb）, conventional tillage straw incorporated （CTsi）, and conventional tillage straw burnt （CTsb） as main plots and N （200 kg ha-1） was applied as split form viz., control （no nitrogen＆no splitting, N0S0）;2 splits of total N, half at sowing and half at the 1st irrigation （i.e., 20 d after sowing （DAS）） （NS1）;3 splits of total N, 1/3 at sowing, 1/3 at the 1st irrigation, and 1/3 at the 2nd irrigation （NS2）;4 splits of total N, 1/4 at sowing, 1/4 at the 1st irrigation, 1/4 at the 2nd irrigation （45 DAS）, and 1/4 at the 3rd irrigation （70 DAS） （NS3）;and 4 splits of total N, 1/4 at the 1st irrigation, 1/4 at the 2nd irrigation, 1/4 at the 3rd irrigation, and 1/4 at the 4th irrigation （95DAS） （NS4） as sub plots. The results showed that the most pikes m-2, grains/spike, 1 000-grain weight, grain yield, and N use efifciency （NUE） were obtained at zero tillage, straw retained and 4 splits application of total N （i.e., at sowing 20, 45 and 70 d after sowing）. The results indicated that ZTsr with application of 200 kg N ha-1 in 4 equal splits viz. at sowing 20, 45 and 70 d after sowing is an appropriate strategy that enhanced wheat yield （7 436-7 634 kg ha-1） and N efifciency （28.6-29.5 kg kg-1） in rice-wheat system.

Development of component geographic information systems applying in forest resources management

The history, current situation, and development trend of GIS (Geographic Information System) applied in the forest resources management were discussed in this paper. On the basis of geographic spatial characteristics of forest resources data, a component geographic information system (ComGIS) was developed for forest resources management. The system embeds a GIS ActiveX control MapObjects (Inc. ESRI) on Visual C++ platform. System design, data organization and achieving way were studied and expatiated by taking Xigangzi Forestry Centre as study object. The system has many useful functions,, such as adding and display of various map layers, zoom of map by wheeling mouse, attribute and spatial data querying, map auto roaming, features rendering based on the spatial trait of data, label controlling through attribute data band with vector graph, as well as output of 'Column chart' for showing the result of statistics. At the same time, parts of source codes are attached.

Improving nitrogen management for zero-tillage rice in China

Zero-tillage has become increasingly attractive in rice production in China.This study was conducted to determine the feasibility of two possible improved N management practices with fewer N applications in zero-tillage rice:(1)two split applications of urea at75 kg N ha^(-1)at mid-tillering and 45 kg N ha^(-1)at panicle initiation(U_(120–2)),and(2)a single application of cross-linked polyacrylamide-coated urea(a slow-release fertilizer)at midtillering at a rate of 150 kg N ha^(-1)(PCU_(150–1)).Three field experiments were conducted to compare grain yield and N-use efficiency among several N treatments:a zero-N control(CK),U_(120–2),PCU_(150–1),a single application of urea at mid-tillering at a rate of 150 kg N ha^(-1)(U_(150–1)),and a commonly recommended N management practice for conventional tillage rice(three split applications of urea with 75 kg N ha^(-1)as basal,30 kg N ha^(-1)at mid-tillering,and 45 kg N ha^(-1)at panicle initiation)(U_(150–3)).Treatments with N application(U_(120–2),PCU_(150–1),U_(150–1),and U_(150–3))produced 1.08–3.16 t ha^(-1)higher grain yields than CK.Grain yields under both U_(120–2)and PCU_(150–1)were comparable to that in U_(150–3).Recovery efficiency of N(RE_N),agronomic N-use efficiency(AE_N)and partial factor productivity of applied N(PFP_N)were increased under U_(120–2)and were similar under PCU_(150–1)to those under U_(150–3).U_(150–1)showed lower grain yield,RE_N,AE_N,and PFP_Nthan U_(150–3).These results suggest that U_(150–3)can be replaced with U_(120–2)to achieve both an increase in N-use efficiency and a reduction in number of N applications and or by PCU_(150–1)to achieve a maximum reduction in number of N applications in zero-tillage rice production in China.

Effects of Tillage Management Systems on Residue Cover and Decomposition

The effects of tillage methods on percent surface residue cover remaining and decomposition rates of crop residues were evaluated in this study. The line transect method was used to measure residue cover percentage on continuous corn ( Zea mays L.) plots under no tillage (NT), conventional tillage (CT), chisel plow (CH), and disk tillage (DT). Samples of rye ( Secale cereale L.) and hairy vetch ( Vicia villosa Roth) were used for residue decomposition study. Results showed that the percentage of residue cover remaining was significantly higher for NT than for CH and DT and that for CT was the lowest (<10%). For the same tillage system, the percent residue cover remaining was significantly higher in the higher fertilizer N rate treatments relative to the lower fertilizer N treatments. Weight losses of rye and vetch residues followed a similar pattern under CT and DT, and they were significantly faster in CT and DT than in NT system. Also, the amounts of residue N remaining during the first 16 weeks were always higher under NT than under CT and DT.

Revolution in the diagnosis and management of hepatitis C virus infection in current era

Chronic hepatitis C virus(HCV)infection is a major global public health problem,particularly in developing part of the world.Significant advances have been made in the early diagnosis and treatment of the disease.Its management has been particularly revolutionized during the past two decades.In this review,we summarize the major advances in the diagnostic and management armamentarium for chronic HCV infection.The focus of the present review is on the newer directly acting anti-viral agents,which have revolutionized the management of chronic HCV infection.Management of uncomplicated chronic HCV infection and of specific complications and special at-risk populations of patients will be covered in detail.Despite the advent and approval of highly effective and well tolerable oral agents,still many challenges remain,particularly the affordability,the equitable distribution and access to later drugs.The World Health Organization aims to eliminate viral hepatitis including HCV by 2030 since its poses a major public health threat.There is an urgent need to ensure uniform and early access to diagnostic and therapeutic facilities throughout the world if the later goal has to be realized.

莫来石-Ti(C,N)复合材料的制备及其力学性能研究

以TiO_(2)粉、石墨粉、Al/Si/Al_(2)O_(3)复合粉体为原料,在氮气气氛下经1400℃~1600℃保温2 h,采用碳热还原氮化法制备得到莫来石-Ti(C,N)复合材料,研究了烧成温度对复合材料物相组成、微观结构与力学性能的影响。结果表明:经1400℃热处理后,试样的物相组成为Ti(C,N)、SiO_(2)和硅线石。随热处理温度升高至1450℃~1600℃,硅线石消失的同时,试样出现了短柱状莫来石,并与无定形SiO_(2)紧密连接,形成有效的化学结合。当烧成温度为1500℃时,大量开口气孔随颗粒重排、界面移动而消失,材料颗粒间结合较为紧密,气孔数量明显减少,该烧成温度下试样具有最佳综合性能,其体积密度、弹性模量、抗折强度和维氏硬度分别为(3.48±0.02) g·cm-3、(138.5±0.1) GPa、(158.0±0.03) MPa和(21.01±0.01) GPa。

Animal Hospital Management System Design Based on C/S/S Structure

By analysis of the functions of animal hospital＇s departments, combining with management information development truth, the paper developed animal hospital management system. The system included six modules, like system management module basic information management module, sections management module, and so on. The paper used Visual C＋＋6.0 and SQL Server 2000, and ODBC database accessing technology, which can encapsulate any database table and operation into class. The system could make any window to share table＇s operation to realize hospital management quickly and efficiency.

Hairy Vetch and Triticale Cover Crops for N Management in Soils

Over-application of fertilizer to cropland adversely affects both environmental and agricultural ecosystems. This study examined whether planting a legume-based winter cover crop mix offsets fertilizer application via natural nitrogen inputs. The influence of the cover crop mixture on available nutrients was also assessed. Hairy vetch (Vicia villosa) and winter triticale (×triticosecale) cover crops were planted in fall and terminated in May. Soil fertility data was collected before and after planting the winter cover crop to determine the effect on fixing nitrogen and soil phosphorus, potassium and organic matter levels. Increases of soil ammonium were observed in plots with cover crop treatments. A triticale-hairy vetch cover crop mix was successful at scavenging P for future crops and appears to hold promise for long-term soil fertility benefits.

A Key Management Scheme for ZigBee in AMI of Smart Grid

Advanced metering infrastructure( AMI) is a critical part of the smart grid,and ZigBee is playing an increasingly important role in AMI.The cyber security is the prerequisite to ensure the reliable operation of AMI.To guarantee the ZigBee communication security in AMI,a key management scheme based on the elliptic curve cryptosystem( ECC) is proposed.According to the ways of information transformation in AMI,the scheme is categorized as unicast communication key management process and multicast communication key management process.And in the scheme,the selection of elliptic curve,the calculation of ZigBee node's ECC public key and private key,the establishment and distribution of the link key in unicast communication,and the establishment and distribution of the network key in multicast communication are elaborated.The analysis results show that the proposed key management scheme is secure,and consumes less memory and energy,thus,can meet the demands of communication security of AMI.

A Study on Compensation for Management and Protection Expenses of Non-commercial Forests

This paper analyzes the compensation nature of non-commercial forests under different ownership from two aspects, namely, whether the property right is limited and whether the management and protection expense has been incurred: there are no economic loss compensation problems caused by changes and limitation of property rights for the state-owned non-commercial forests with only the compensation on management and protection expense; but for the non-commercial forests owned by collectives or individuals, double compensation for both the economic loss and management expense exists because of limitation on the property right. In addition, an inframarginal economic analysis framework has been built for the management and protection compensation problems faced by non-commercial forests under different ownership in the perspective of the division of labor. Research results show that: the compensation standard for the management and protection expenses of non-commercial forests shall fall in between the "completely self-sufficient forestry economic structure U(Ayz)" and the "completely specialized productive structure of non-commercial forests U(B1)".

Stochastic Design of Enhanced Network Management Architecture and Algorithmic Implementations

The paper is focused on available server management in Internet connected network environments. The local backup servers are hooked up by LAN and replace broken main server immediately and several different types of backup servers are also considered. The remote backup servers are hooked up by VPN (Virtual Private Network) with high-speed optical network. A Virtual Private Network (VPN) is a way to use a public network infrastructure and hooks up long-distance servers within a single network infrastructure. The remote backup servers also replace broken main severs immediately under the different conditions with local backups. When the system performs a mandatory routine maintenance of main and local backup servers, auxiliary servers from other location are being used for backups during idle periods. Analytically tractable results are obtained by using several mathematical techniques and the results are demonstrated in the framework of optimized networked server allocation problems. The operational workflow give the guidelines for the actual implementations.