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1.
2.
大型综合室内亲子乐园属于高大空间,设有游乐设施和游戏的特殊性使得对空间的舒适性要求一致,但是送风气流遇阻严重,室内存在较多气流死角,影响室内空气质量和儿童健康。因此其空调设计不仅需要考虑温度、风速的空间均匀度,还要考虑各点的空气龄和PMV-PPD指标。以天津某亲子乐园为研究对象,利用scSTREAM软件对适用于该房间的辐射供冷加新风、置换通风、混合通风三种空调方式的送风效果进行数值模拟分析,从流场的均匀性、人员的热舒适性等方面对模拟结果进行探讨,研究结果表明辐射供冷加新风方式的空间均匀性和PMV指标最佳,混合通风方式的空气龄最小。 相似文献
3.
采用异佛尔酮二异氰酸酯(IPDI)、聚乙二醇200、400、600、800(PEG200、PEG400、PEG600、PEG800)、2,2-二羟甲基丙酸(DMPA)、1-苯基-1,2-乙二醇、中和剂三乙胺(TEA)、甲乙酮肟等为原料,制备了一种阴离子聚氨酯分散剂.通过FTIR、GPC、TG表征了分散剂的结构与性能.利用自制的分散剂采用研磨法制备了液体靛蓝分散液,以液体靛蓝分散液粒径、离心稳定性、储存稳定性为指标,探讨了分散剂链长、用量对分散液性能的影响.结果表明,研磨1 h后,以PEG400为软段合成的聚氨酯分散剂用量为染料质量的60%时制备的液体靛蓝粒径为277.1 nm,1000 r/min离心稳定性达到93.98%,3000 r/min离心稳定性为51.13%,常温放置7 d后粒径变化在20 nm以内,染色后织物的颜色深度(K/S)为10左右,约是粉状靛蓝染色K/S的2倍,染色织物的颜色性能并未改变,SEM显示分散体颗粒大小分布均匀,与分散剂甲基萘磺酸钠的甲醛缩合物(MF)和木质素85A相比,其分散体系稳定性差别不大. 相似文献
4.
Improved homogenization of Ni in sintered steels through the use of Cr-containing prealloyed powders
The homogenization of Ni in powder metal (PM) steel compacts is usually difficult even after high-temperature sintering at
1250°C. An earlier study by the authors demonstrated that this problem can be alleviated through the addition of 0.5 wt pct
Cr in the form of stainless steel powders. To further improve the microstructure and mechanical properties of Ni-containing
PM steels and to understand the mechanisms, an attempt was made in this study using the Fe-3Cr-0.5Mo prealloyed powder as
the base material. The results showed that the distribution of the Ni additives was significantly improved. As a result, the
tensile strength of the Fe-3Cr-0.5Mo-4Ni-0.5C compact sintered at 1250°C reached 1323 MPa. The elongation was higher than
1 pct. These sinter-hardened properties, which were attained using a slow furnace cooling rate, were comparable to those of
the sinter-hardened alloys reported in the literature using accelerated cooling and were equivalent to those of the best quenched-and-tempered
alloys registered in the Metal Powder Industries Federation (MPIF) standards. These improvements were attributed to the positive
effect of Cr addition on alloy homogenization due to the reduction of the repelling effect between Ni and C, as was demonstrated
through the thermodynamic analysis using the Thermo-Calc program. 相似文献
5.
This study was undertaken to develop a modified atmosphere package to control microbial growth in ready‐to‐eat (RTE) products stored at ambient temperature. Ethanol and/or limonene associated with modified atmosphere (CO2 : O2 : N2 = 30% : 5% : 65%) was used to inhibit the growth of total air‐borne microorganisms and Escherichia coli in RTE products stored at 25°C. The results indicated that 0.05% ethanol vapour in the headspace was effective to inhibit the growth of air‐borne microorganisms and E. coli at 25°C for 72 h in a model study, and the effectiveness was related to ethanol content. Both 73 ppm limonene and 0.05% ethanol vapour enhanced the bacteriostatic effect of modified atmosphere in RTE sushi roll products, and no off‐flavour was detected using this formulated gas; however, no significant inhibitory effect was observed for RTE cold noodle products. This study concludes that combinations of carbon dioxide, ethanol or limonene vapours are effective to inhibit microbial growth in RTE food at ambient temperature, and the outcome may be due to the hurdle effect. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
6.
以Si-MCM-41、Al-MCM-41(1) (n(Si)/n(Al)=15)、Al-MCM-41(2) (n(Si)/n(Al)=10)以及用NH4NO3或HAc的醇溶液分别与Si-MCM-41离子交换所得的H-MCM-41(N)和H-MCM-41(H)为载体制备了系列Ru/MCM-41催化剂。采用N2吸附、XRD和H2-TPR表征了负载Ru前后催化剂的结构及Ru在各种载体表面上的分散状态。以0.5%(质量分数)苯的环己烷溶液为模型化合物,在298K、3.0MPa反应条件下,考察了上述催化剂的苯液相加氢反应性能,并与Ru/HY、Ru/H61538;和Pt/MCM-41催化剂进行了比较。结果表明,载体MCM-41的n(Si)/n(Al)和表面化学组成等性质对Ru在其表面上的分散状态、还原性及催化性能均有影响。对苯的转化率与反应时间的关系曲线进行拟合,发现其遵循一级动力学方程,加氢反应速率常数按照Ru/Al-MCM-41(2)相似文献
7.
Xue‐Yong Liu Xiao‐Bin Ding Zhao‐Hui Zheng Yu‐Xing Peng Albert S
C Chan C
W Yip Xin‐Ping Long 《Polymer International》2003,52(2):235-240
Amphiphilic magnetic microspheres ranging in diameter from 5 to 100 µm were prepared by dispersion copolymerization of styrene and poly(ethylene oxide) vinylbenzyl (PEO‐VB) macromonomer (MPEO) in the presence of Fe3O4 magnetic fluid. The effects of various polymerization parameters on the average particle size were systematically investigated. The average particle size was found to increase with increasing styrene concentration and initiator concentration. It also increased with decreasing stabilizer concentration and molecular weight of MPEO. The content of the hydroxyl groups localized in the microspheres ranged from 0.01 to 0.2 mmol g?1. © 2003 Society of Chemical Industry 相似文献
8.
北部湾盆地福山凹陷CO2气成因探讨 总被引:2,自引:1,他引:1
北部湾盆地福山凹陷油气钻探中发现了高含CO2气的天然气气藏。对CO2气稳定碳同位素、伴生稀有气体氦和氩同位素进行了分析研究,结果显示,福山凹陷CO2气稳定碳同位素偏重,(13CCO2为-5.01~-10.08‰,绝大多数样品大于-7.0‰,为无机成因CO2气特征;伴生稀有气体氦同位素3He/4He值为(4.74~5.03)×10-6,R/Ra值为3.38~3.59;伴生稀有气体氩同位素40Ar/36Ar值为1881~2190,也显示出幔源或壳幔混合CO2气的特征。综合判定认为,福山凹陷CO2为壳幔混合成因。始新统流沙港组岩浆岩体分布特征与CO2气藏分布范围基本一致,也表明幔源-岩浆可能是福山凹陷CO2气的主要来源。与南海北部边缘盆地其它地区如珠江口盆地西部、琼东南盆地东部CO2气成因一致,都为幔源-岩浆来源,或壳幔混合来源。 相似文献
9.
丙烯腈装置回收塔内聚合物生成原因的分析 总被引:2,自引:0,他引:2
针对丙烯腈生产过程中回收塔内聚合物堵塞降液管造成回收塔运行周期短的问题,通过对丙烯腈回收塔内各组分分布的模拟计算,直观显示了回收塔内各组分的浓度分布,发现了回收塔的聚合段与丙烯醛的富集段相吻合的现象,初步得出了回收塔内局部聚合的原因;通过对塔内聚合物的特性分析和评判,进一步证实了“回收塔内局部聚合严重是由于在聚合段丙烯醛聚集引起”这一现象;根据模拟计算结果和实际运行经验,提出了预防聚合物堵塞降液管的措施,并进行了部分生产验证,为丙烯腈生产企业延长装置运行周期提供了理论指导。 相似文献
10.
Wu-An Kuo TingTing Hwang Wu A.C.-H. 《Very Large Scale Integration (VLSI) Systems, IEEE Transactions on》2006,14(1):81-85
This paper presents a novel power-driven multiplication instruction-set design method for application-specific instruction-set processors (ASIPs). Based on a dual-and-configurable-multiplier structure, our proposed method devises a multiplication instruction set for low-power ASIPs. Our method exploits the execution sequences of multiplication instructions and effective bit widths of variables to reduce power consumed by redundant multiplication bits while minimizing the multiplication execution time. Experimental results on a set of DSP programs demonstrate that our proposed method achieves significant power reduction (up to 18.53%) and execution time improvement (up to 10.43%) with 18% area overhead. 相似文献