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1.
The high temperature heat pump and desiccant wheel(HTHPDW) system can make full use of heat released from the condenser of heat pump for DW regeneration without additional heat. In this study, DW operation in the HTHPDW system was investigated experimentally, and the optimization analysis of HTHPDW system was carried out. The performance of DW had influence on the dehumidification(evaluated by dehumidification and regeneration effectiveness) and cooling load(evaluated by thermal and adiabatic effectiveness). The results show that the enthalpy increase occurred in all the experiments. Compared to the isosteric heat, heat accumulation in the desiccant and matrix material and heat leakage from regeneration side to process side have greater influence on the adiabatic effectiveness. Higher regeneration temperature leads to lower adiabatic effectiveness that increases more cooling load of the system. When the regeneration temperature is 63℃, the maximal dehumidification effectiveness is 35.4% and the satisfied adiabatic effectiveness is 88%, which contributes to the optimal balance between dehumidification and cooling. 相似文献
2.
0,China)In this paper,the differentiation principle is used to handle planar dimension chains.It simplifies the process of analysis,improves the accuracy and rationality of calculation because of considering the angular deviation that is usually ignored by the engineer.We put forward some relatively simple and efficient formula,and analyze dimension tolerance zone 相似文献
3.
We investigated the structural behavior and bearing capacity of system scaffolds. The research showed that the critical load of a system scaffold structure without diagonal braces is similar to that of a door-shaped steel scaffold structure. Joint stiffness between vertical props in system scaffolds can be defined based on a comparison between analytical and experimental results. When the number of scaffold stories increases, the critical loads of system scaffolds decrease. Diagonal braces markedly enhance the critical load of system scaffolds. The coupling joint position between vertical props should be kept away from story-to-story joints to prevent a reduction in critical loads. The critical load of a system scaffold decreases as the quantity of extended vertical props at the bottom of the structure increases. A large Christmas tree set up by system scaffolds under various loads was used as an example for analysis and to check the design of system scaffolds. 相似文献
4.
Hydantoinase and N-carbamoylase play important roles in the production of optically pure amino acids from racemic 5-monosubstituted hydantoins. In this report, hydantoinase and the N-carbamoylase from Burkholderia cepecia, njut01 were purified to homogeneity by chromatography (Pharmacia Explorer 100 system). The substrate specificity, enantioselectivity, pH dependence of activity and temperature stability of the activity were characterized. The results show that the hydantoinase and N-carbamoylase induced from Burkholderia cepecia, njut01 are both strict D-stereo selective enzymes. They both hydrolyze substrates with side chains containing aliphatic and aromatic residues with higher activity and affinity toward aromatic than aliphatic substituted substrates. The hydantoinase is a homotetramer with subtmit molecular weight near 52,000 and is active between pH 6.5 and 10 with an optimum near pH 9.0. The enzyme is active at temperatures up to 60~C, however, it appears instable at higher temperatures. The subunit molecular weight of N-carbamoylase is about 35KD. The N-carbamoylase is active in the pH range from 6.0 to 9.5. The optira-pH is 7.2 and the optinfizing bioconversion temperature of the N-carbamyolase is 52℃. 相似文献
5.
Tung oil-based polyols were synthesized by the esterification and transesterification between Tung oil-based anhydride and butanediol. The hydroxyl values of the polyols prepared were tested and discussed. Polyurethane was prepared by using Tung oil-based polyols and/or poly （propylene glycol） as polyols and by using isophorone diisocyanate as isocyanate. The effect of the ratio of Tung oil-based polyols to poly （propylene glycol） on the proper- ties of polyurethane prepared was investigated by the water resistance, alcohol resistance and hardness tests. The results show that Tung oil-based polyols are effective to improve the hardness, water resistance and alcohol resistance of polyurethane. 相似文献
6.
Enhanced degradation of carbon tetrachloride by surfactant-modified zero-valent iron 总被引：1，自引：0，他引：1
Sorption of carbon tetrachloride （CT） by zero-valent iron （ZVI） is the rate-limiting step in the degradation of CT, so the sorption capacity of ZVl is of great importance. This experiment was aimed at enhancing the sorption of CT by ZVI and the degradation rate of CT by modification of surfactants. This study showed that ZVI modified by cationic surfactants has favorable synergistic effect on the degradation of CT. The CT degradation rate of ZVI modified by cetyl pyridinium bromide （CPB） was higher than that of the unmodified ZVI by 130%, and the CT degradation rate of ZVI modified by cetyl trimethyl ammonium bromide （CTAB） was higher than that of the unmodified ZVI by 81%. This study also showed that the best degradation effect is obtained at the near critical micelle concentrations （CMC） and that high loaded cationic surfactant does not have good synergistic effect on the degradation due to its hydrophilicity and the block in surface reduction sites. Furthermore degradation of CT by ZVI modified by nonionic surfactant has not positive effect on the degradation as the ionic surfactant and the ZVI modified by anionic surfactant has hardly any obvious effects on the degradation. 相似文献
7.
Experimental study on bonding properties between steel strand and concrete at cryogenic temperatures
To study the bonding properties between steel strand and concrete at room and cryogenic temperatures, a series of center pullout experiments were conducted on 96 bonding anchorage specimens at the lowest temperature of-165 ℃. The impacts on the bonding property of such parameters as the temperature, concrete strength, the relative concrete cover thickness, and the relative anchorage length were analyzed. The test results indicate that the changes in temperature have a clear effect on the bonding property between steel strand and concrete. As the temperature decreases, the bond stress, which corresponds to a 1 mm slip of steel strand in relation to concrete, and the ultimate bond strength initially increase and subsequently decrease at the inflection point of-80 ℃. The impact of the concrete strength on the bonding property, as shown by the tensile strength and the moisture content interaction, indicates that the bond stress vs concrete strength curve initially increases and later decreases with a decrease in temperature; the bond stress vs concrete cover thickness curve linearly increases, but the bond stress vs anchorage length curve linearly decreases at first and finally levels off. 相似文献
8.
《浙江大学学报(A卷英文版)》2021,(2)
Pyrolysis is a cost-effective and safe method for the disposal of radioactive spent resins. In this work, the catalytic effects of V_2O_5 on the pyrolysis of cation exchange resin are investigated for the first time. The results show that it is a better catalyst than others so far studied and achieves a lowering of final pyrolysis temperature and residual rate simultaneously when aided by physical blending. The maximum reductions of the final pyrolysis temperature and the residual rate are 173 ℃ and 11.9%(in weight), respectively. Under the action of V_2O_5, low-temperature(445℃) removal of partial sulfonic acid groups occurs and the pyrolysis of the resin copolymer matrix is promoted. This is demonstrated by the analysis of pyrolysis residues at different temperatures by X-ray photoelectron spectroscopy(XPS) and element analysis. The catalytic activity of V_2O_5 is determined by effects both at acid sites and oxidation-reduction centers via H_2-TPR(temperature programmed reduction), O_2-TPD(temperature programmed desorption), CO_2-TPD, and NH_3-TPD. The catalytic effect of oxidation-reduction centers in V_2O_5 is achieved by close contact with the sulfur bond through chemisorption under the effect of acid sites. V_2O_5 is also believed to be the reason for the removal of partial sulfonic acid groups at lower temperatures(445℃). V_2O_5 is an effective catalyst for spent resin pyrolysis and can be further applied in industry. 相似文献
9.
Objective: To explore better therapy and reduce the rate of re-relapse of primary nephritic syndrome in children who had been treated with corticosteroids but relapsed. Methods: Eighty relapsers were enrolled from Jan. 1994 to Apr. 2000, who were randomly divided into two groups. The treatment group (n=39) had been treated with tripterysium glucosides for three months, with the control group (n=41) members were treated with cyclophosphmide (CTX) by intermission intravenous pulse, with total dose of CTX not being more than 150 mg/kg. Prednisone, meanwhile, was given to both groups. The total treatment period of prednisone was prolonged by 12-18 months. Results: After following up for 3-7 years, the re-relapse rates of both groups were observed. The re-relapse rate of the treatment group was 28.2% to 29.3% in the CTX-controlled group. The re-relapse rates between two groups were almost similar, and with no observed significant difference (P>0.05). The side effect of tripterysium glucosides was less than that of CTX. Conclusion: For the treatment of relapsing nephritic syndrome in children, the combination of tripterysium glucosides and prolonged corticosteroid therapy is as effective as the regimen of CTX plus prolonged use of prednisone. 相似文献
10.
Xue-cheng Wu Qin-hui Wang Chen Tian Zhong-yang Luo Meng-xiang Fang Ke-fa Cen 《浙江大学学报(A卷英文版)》2008,9(7):922-931
Particle rotation plays an important role in gas-solid flows. This paper presents an experimental investigation on the spatial distribution of average rotation speed for glass beads in the upper dilute zone of a cold circulating fluidized bed （CFB） riser. It is shown that in the horizontal direction, the average rotation speed in the near-wall area is larger than that in the center area, while in the vertical direction, it decreases as the height increases. The reason resulting in this distribution is analyzed by considering several factors including particle size, particle shape, particle number density, particle collision behavior, and the surrounding flow field, etc. The effects of CFB operation conditions on the spatial distribution of average rotation speed are also studied. The results show that the increasing superficial gas velocity increases the average rotation speed of particles in the near wall area but takes nearly no effect on that in the center area. The external solids mass flux, however, takes the opposite effect. It is found that the average rotation speeds of particles in both areas are increased as the total amount of bed material increases. 相似文献
11.
马海珠 《浙江教育学院学报》2005,(5):46-52
利用旋转异构态模型和伪立体化学平衡统计方法,得到考虑侧基的均方回转半径及温度系数的改进公式,研究典型的大侧基聚衣康酸酯链的构象和构型性质.并通过数值计算,研究无规聚衣康酸酯链均方回转半径特征比、温度系数与构象能的关系,研究链规整程度对均方回转半径特征比的影响. 相似文献
12.
马海珠 《浙江教育学院学报》2006,(4):55-60
利用构象．构型统计方法，推导了均方回转半径和温度系数公式，并对同为单侧基二态模型的聚苯乙烯和聚丙烯酸甲酯链均方回转半径特征比作了计算比较，发现构象能对链无扰尺寸和温度系数的依赖关系是不同的，说明侧基对聚合物性质有重要影响． 相似文献
13.
马海珠 《浙江教育学院学报》2004,(5):1-5,22
应用构象统计方法和改进的侧基旋转异构态模型,推导了对称取代基链的均方回转半径特征比《S2》/2xl2公式,可研究聚二甲基硅烷链的柔顺性,根据特征比与链长的关系,得到聚二甲基硅烷链长链特征比值0.94,结果还与聚二甲基硅氧烷链前期计算值作了比较. 相似文献
14.
研究了长链氨羧络合剂N,N′-二(十二烷基)乙二胺二乙酸的氯仿溶液对镨(Ⅲ)的萃取行为,考察了初始水相酸度、萃取剂浓度、相比及温度等对Pr(Ⅲ)萃取率的影响.结果表明,在pH=6～7条件下对Pr(Ⅲ)有很高的萃取率,且随萃取剂浓度增大而增大;在25℃～35℃范围内lgD随温度升高线性增大.用摩尔比法测得Pr(Ⅲ)与萃取剂的摩尔比为2:1 相似文献
15.
邬立灏 《常熟理工学院学报》2008,22(8):58-64
以对苯二甲酸二甲酯和1,4-丁二醇为原料,通过添加第三单体5-磺酸钠间苯二甲酸二甲酯制备出大分子链上含离子基团的聚对苯二甲酸丁二酯离聚物（SPBT）．用差示扫描量热法（DSC）研究其非等温结晶的过程,发现随着离子基团的引入结晶过程变得复杂,其成核与生长机理变化不大,离子基团的存在增加了大分子链表面的自由能从而改变了结晶性能． 相似文献
16.
采用表观黏度法,以黏度增长因子R为指标,对聚丙烯酰胺(PAM)与聚乙二醇(PEG)在水中的相互作用进行研究,并考察PAM摩尔分数、PEG相对分子质量、剪切速率和温度对其相互作用的影响。结果表明:混合体系中PAM与PEG之间的相互作用表现为表观黏度的降低,主要为疏水、氢键及相互缠结作用等;当体系中PAM的摩尔分数为0.6时,相互作用最强;该作用随PEG相对分子质量的增大而略增强,随剪切速率的增加先增大后减小,随温度的升高先减小后增大。表观黏度法快捷简便,适用于溶液中聚合物分子间相互作用的研究。 相似文献
17.
应用高分子反应统计理论,对超支化高分子体系的玻璃化温度受端基和支化点密度的影响进行了研究,得到了体系的玻璃化温度与反应程度的解析表达形式,并进一步以AB3型和加核的A3-ABg(g=2,3,4)型超支化高分子的缩聚反应体系为例探讨了反应程度对玻璃化温度的影响。 相似文献
18.
对于两个具有任意非零色散系数的弱耦合Korteweg-deVries（KdV）方程,得到一类微扰孤子解及其存在性条件．数值结果表明,弱耦合相互作用仅给未扰孤子对以小的修正,不改变孤子的特性． 相似文献
19.
INTRODUCTION Preparation and electrical properties ofpoly(arylene)s having π-conjugation system along thepolymer chain are the subject of recent interest(Skotheim et al., 1997; Nalwa, 1997; Yamamoto,2002). Among the poly(arylene)s, poly(p-phenylene),poly(pyridine-2,5-diyl) and poly(thiophene-2,5-diyl)are the most fundamental polymers and had beenextensively studied (Skotheim et al., 1997; Yama-moto, 2002; Nurulla et al., 2001). However, thesepolymers show only… 相似文献
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