长白落叶松苗木质量与造林效果关系的比较

以苗高和地径为分级标准,将长白落叶松播种苗(1-0)分成2级:Ⅰ级苗和Ⅱ级苗,将移植苗(1-1)分成3级:特级苗、Ⅰ级苗和Ⅱ级苗,以苗龄和等级为试验因子进行了根生长潜力和造林效果试验。结果表明:①1 cm新根数量（TNR1）在苗龄之间和等级之间差异均显著,说明TNR1能代表不同苗龄和等级长白落叶松苗木的发根能力,可作为评价苗木质量的活力指标。②播种苗苗高和地径生长量均大于移植苗,所有处理中移植苗特级苗的生长量和生长率最低。造林成活率依次为:移植苗和播种苗的Ⅰ级苗移植苗Ⅱ级苗播种苗Ⅱ级苗和移植苗特级苗。通过逐步多元回归分析,得出苗木形态指标与根生长潜力及生长量之间存在很强的相关性,可以用形态指标预测长白落叶松苗木的活力状况和造林后的生长表现。从造林成活率和生长量两个方面来看,再考虑到培育周期和育苗成本,造林效果最好的是移植苗Ⅰ级苗,其次是播种苗Ⅰ级苗和移植苗Ⅱ级苗。      

Ecological Coupling Theory and the Method System of Urban countryside Space Planning

Since P. R. China has experienced extensive land resource use, environmental degradation, lagging rural development and other difficulties in 20th century, urban countryside integration and ecological planning has become an important subject to build a harmonious society in the 21st century. The country attempted to use complexity science and ecological thinking based on recognizing the relationship between the city and countryside and raising the city countryside space ecology coupling concept to construct a city countryside space planning methods system consisting of the identification of urban and rural land uses, urban and rural non construction land planning, city countryside coupled environmental conditions assessment, coordinated city countryside space development and city countryside space system fractal optimization, and more.     

Analysis of the Kinetic Theory of Submerged Abrasive Water Jets

Abrasive water jets can incise objects with strong rigidity under water. The analytical means of kinetic theory is optimal for theoretical problems of submerged abrasive water jets. The flow characteristics in submerged abrasive water jets were analyzed based on kinetic theory for multiphase flows. The impact characteristics of every phase in submerged abrasive water jets was analyzed and continuity and momentum equations subsequently were developed for solid, gas and liquids in submerged abrasive water jets. It is shown that if the distributing function of every phase were given, the law of its movement could be ascertained.     

Numeric Analysis of the Dynamic Performance of a Prestressed Concrete Beam

The finite element of a prestressed concrete (PSC) beam is analyzed in a case of diverse prestressing forces. The mechanical model applied is that advanced by Clough for a concrete beam bearing axial force. The results indicate that the beam frequencies decrease with increasing prestressing force. A dynamic experiment of a non bonded PSC beam was carried out to validate the veracity of the finite element analysis. Test beam frequencies increase with increasing prestressing force. The analysis model thus is unfit for frequency analysis of a PSC beam. The determinant factor of frequencies is analyzed, and the dynamic model is modified according to experimental results. The modified model analysis result shows that: the calculated frequencies of mode 1 agree with the test results well; the frequencies of mode 2 posses some errors; and, the modified model can reflect the direction of frequency change along with the change of prestressing force well.     

Deformation Properties of Backfill Grouting in Shield Tunnel

Utilizing the self made unit body model test apparatus, the deformation laws of backfill grouting were studied under different grouting pressures, different soil conditions and different ground water pressures. It was shown that high grout pressures can accelerate the consolidation rate of grout drainage and increase final deformation amount. And soil permeability coefficient was an important factor to grout deformation. The ground water pressure was more important for sand soil while the grout pressure was for clay soil. The proposed apparatus can truly reflect stress status of grout injected to tail void. And grout deformation properties were helpful to clarify the stratum stress release and stratum deformation of backfill grouting.      

Performance of A Sludge Reduction System on Removal of Nitrogen and Phosphorous Controlled by Low Dissolved Oxygen

The influences of dissolved oxygen (DO) on the removal process of nitrogen and phosphorous in a sludge reduction system had been studied by controlling aeration amounts. It was found that under the conditions of low doses of 2,4,5trichlorophenol (TCP), endogenous sour values of activated sludge increased with the extension of low DO state duration in SBR system and the decrease of cyclic average DO, which led to a low DO environment favored the formation of simultaneous nitrification and denitrification(SND).TCP concentration was recommended as 2mg / L and cyclic average DO value in SBR system was kept at 2mg / L based on the impacts of TCP concentration on sludge reduction, removal of nitrogen and phosphorous and sludge performance. Compared with the control system, aeration amounts increased by 23% and the discharge of excess sludge decreased by 34.6%. The water quality in effluents was equivalent in the aeration sludge reduction system with 2mg/LTCP, which met the discharge standards. Therefore, it was indicated that the removal of nitrogen and phosphorous and sludge reduction can obtain excellent performance in TCP system under low DO state with removing Phosphrous rich sewage.     

Fire and explosion hazard analysis of the urea synthesisproduction process

On the basis of identifying and analyzing harmful risk factors in the urea synthesis production process of a factory, the production process is assessed and analyzed using the Dow chemical company fire and explosion index method. The related indexes are f     

Performance analysis and comparison of IEEE 802.11 distributed coordination function and improved schemes

To improve the media access control mechanism and enhance the performance of large scale wireless LANs, the distributed coordination function of IEEE802.11 standard and two typical improved schemes are studied extensively. Compared with the distributed coordination function, the fast collision resolution mechanism greatly enhances the throughput, but deteriorates the delay jitter and fairness of wireless LANs. The new self adaptive distributed coordination function markedly improves the delay jitter and fairness performance, while enhancing the throughput of wireless LANs to a certain degree. Hence, with further improvement, the new self adaptive distributed coordination function is more suitable for large scale wireless LANs for multimedia information transmission.     

Design and application of hospital service info structurebased on medical knowledge flow

To counter deficient medical knowledge sharing and the low efficiency cooperative diagnosis between doctors, the knowledge flow from knowledge management (KM), knowledge acquisition and knowledge supply are established as the core info structure of a hospital KM model. This is done by combining heavy idea exchange, frequent updating, and intensive use of the medical knowledge. Three important knowledge flow(KF) operations (knowledge refreshing, knowledge migration and knowledge expansion) are proposed. By comparing hospital information management with hospital KM, a hospital KM method based on knowledge flow is constructed. The method emphasizes tracking, monitoring and controlling hospital wide comprehensive process of medical knowledge. A specific clinical diagnosis instance is given for detailed healthcare knowledge flow analysis.      

Generalized conforming quadrilateral membrane element with vertex rotational freedom

A new generalized conforming quadrilateral membrane element is developed by introducing additional rigid vertex rotational freedoms to the normal 4 node quadrilateral membrane element. The rotational stiffness of the present element is not zero so that the singularity of the stiffness matrix is avoided. Numerical analysis of the Cook problem cantilever beam shows that the EAE/Mem element passes the patch test and possesses good convergence, reliability, and precision without a zero energy mode. It provides a lock free solution to the MacNeal beam problem. Numerical results also show that the EAE/Mem element is insensitive to mesh distortion. The results demonstrate that the generalized conforming technique is an efficient tool for developing high performance finite element models.