An optimal operating window for the Bunsen process in the I–S thermochemical cycle

We searched for the optimal compromised operating conditions for the Bunsen reaction of IS thermochemical water splitting, considering the key concerns of the IS cycle: the liquid–liquid equilibrium (LLE) phase separation performance, the characteristics of water distribution between the sulfuric acid (SA) phase and the poly-hydroiodic acid (HI_x) phase, side reaction occurrence, and the effect on operating costs. Experimental data available from a literature survey were combined, and common trends were examined through a series of parametric studies. Based on the results, the optimal operating point and allowable operating window for the Bunsen reaction have been proposed: the optimal point is represented by 4 mol of excess iodine and 11 mol of excess water in the stoichiometry at temperature of 330 K, while the allowable window ranges over for the excess iodine, for the excess water, and for the temperature. After the Bunsen reaction and LLE phase separation, 5 mol of the excess water is distributed to the SA phase and to the HI_x phase. Operating within this window makes it possible to avoid the side reaction and iodine solidification, to increase the HI concentration well above the azeotropic point in the HI_x section, and to minimize operating costs arising from excess iodine and water.     

宝钢3号高炉冷却壁破损机理的热态试验研究

模拟宝钢3号高炉冷却壁的实际工作条件,建立了国内第一台大型冷却壁热态试验炉。通过测量进水温度、进水速度、炉气温度及热冲击等条件对光面冷却壁热面温度的影响,分析了宝钢3号高炉带凸台冷却壁损坏的主要原因。     

随时间推移（TL）地震勘探处理方法研究

随时间推移（TL）地震勘探已经在油田开发领域见到了一些成功的实 ,关于TL地震勘探的可行性论证也有不少文章讨论过,但是对于陆上薄互层（储层厚度小于10m),大地吸收较强,信噪比较低和严重空变激发,接收因素影响条件下的TL地震可行性论证和数据处理还存在一些问题需要解决,本文从实际地震数据问题（如50Hz工业干扰,地层吸收,激光能量和频率空变,近地表鸣震干扰和接收器影响等问题）分析入手,发现这些问题难以用常规处理和互均衡处理方法来解决,为此,本文针对以上问题提出了特殊的处理方法和流程,较好地消除了这些干扰影响,并在不采用互均衡处理条件下获得TL地震储层的差异信息。     

Application of the developed CFD analysis methodology to H2 explosion accidents in an open space

We developed a CFD (Computational Fluid Dynamics) analysis methodology for predicting an overpressure buildup due to a hydrogen explosion as well as the blast wave propagation from the near field to the far field of the hydrogen explosion site with an error range of about ±30% on the basis of test results with the small-scale obstacle at the stoichiometry condition in an open space in the previous research. In this paper, we confirmed the applicability of the developed CFD analysis method to the evaluation of the safety distance between a VHTR (Very High Temperature Reactor) and a hydrogen production facility through the CFD analysis conducted on the HTTR (High Temperature Test Reactor) and the hydrogen production facility in JAEA (Japan Atomic Energy Agency) under an assumption of a hypothetical hydrogen explosion. The application study showed physically reasonable results when compared to the test data performed by SRI (Stanford Research Institute) International, and the CFD analysis methodology is a more useful tool in the evaluation of the safety distance than the MEM (Multi-Energy Method) because the MEM has some drawbacks that it cannot predict an asymmetric explosion phenomenon due to a complicated geometry and an ambient temperature effect on an overpressure buildup. Finally, the developed CFD analysis methodology will be applied to evaluate the safety distance between a VHTR and a hydrogen production facility after KAERI (Korea Atomic Energy Reaches Institute) completes a design work of a VHTR and a production facility.     

跨音速级叶片可控涡设计分析与试验研究

对某涡轮末级,本文采用可控涡方法,通过数值计算与传统自由涡的设计研究对比显示:前者的总总效率较后者提高了0.5%,功率提高了1.18%;可控涡设计通过控制静叶出口气流角使气体质量流量在径向重新分布,从而控制涡轮反动度沿着叶高的斜率变小,根部横向压力梯度的减小减弱了端部的二次流损失,顶部反动度的减小可降低顶部间隙的泄露损失;对可控涡设计静叶片按缩比制成环形叶栅试验件在风洞试验平台上试验,通过对比数值计算和试验的出口截面马赫数、轴向速度、出口速度环量及各截面静压沿型线分布等,可知试验数据和数值计算结果吻合的很好,试验获得的总压损失系数略高于数值计算,试验还表明在3个不同出口马赫数下,总压损失系数随着试验出口马赫数的增大逐步降低。     

Effects of antioxidants on streptonigrin-induced DNA damage and clastogenesis in CHO cells

This study evaluates the comparative efficacy of antioxidant vitamins (ascorbic acid and alpha-tocopherol) and non-vitamin antioxidants (glutathione, cysteine and L-2-oxothiazolidine-4-carboxylate (OTZ)) in modulating the detoxification pathway of lactating dams and suckling murine pups. In dams, 100 mg/kg b.w./day treatment of each of the vitamin and non-vitamin antioxidants induced a significant increase in the hepatic level of acid soluble sulfhydryl (-SH) compared to the modulating efficiency of OTZ, glutathione and alpha-tocopherol in the kidney tissue. In the liver and kidney tissues of suckling pups OTZ and alpha-tocopherol were effective in modulating the -SH level. A statistically significant increase in the hepatic glutathione-S-transferase (GST) level was observed by OTZ, glutathione and alpha-tocopherol, while only OTZ was effective in the kidney tissue of dams and pups. In the murine system, the modulation of cellular GST/GSH status, specifically by OTZ, alpha-tocopherol and interacting antioxidant pool, may potentially ameliorate the pathophysiology of oxidative stress.     

Li2CO3在含碳球团还原中催化机理的研究

通过在氧化铁中添加碳粉和少量Ｌｉ２ＣＯ３添加剂,考察了碱金属化合物和温度对含碳才还原过程的影响,探讨了碱金属化合物的催化机理,实验结果表明,球团还原率随着碱金属化合物添加量而增大,但增大幅度随添加剂增多,温度升高而减小,在球团还原初期,Ｂｏｕｄｏｕａｒｄ反应是还原的限制环节,添加Ｌｉ２ＣＯ３可以降低反应活化能,较高温度下还原后期,氧化铁的气相还原是反应的限制性环节,添加Ｌｉ２Ｃｏ３可以加快Ｆｅ／Ｆ     

Multimodality treatment of 128 patients with locally advanced breast carcinoma in the era of mammography screening using standard polychemotherapy with 5-fluorouracil, epirubicin, and cyclophosphamide: prognostic and therapeutic implications

BACKGROUND: Locally advanced breast carcinoma is associated with a poor prognosis. With single treatment modalities, i.e., surgery and/or radiation therapy, results have been consistently dismal. However, several earlier reports have indicated improvement in survival with a combined modality approach, i.e., the utilization of systemic therapy. METHODS: Between 1991 and 1994, 128 patients with locally advanced noninflammatory or inflammatory breast carcinoma (LABC) were treated with a combined modality strategy consisting of 4-6 courses of preoperative 5-fluorouracil (600 mg/m2), epirubicin (60 mg/m2), and cyclophosphamide (600 mg/m2) (FEC) every 3 weeks, followed by modified radical mastectomy or sector resection with axillary dissection in combination with postoperative radiotherapy and concomitant cyclophosphamide (850 mg/m2). Postoperatively, 3-5 adjuvant courses of FEC therapy were given. Nine percent of the patients received preoperative radiotherapy because the FEC therapy was not sufficiently effective. One-third of the patients were given tamoxifen (20 or 40 mg daily) at the end of the multimodal therapy. RESULTS: Clinical responses were observed in 60% of the patients; 5% had complete responses (CR) and 55% had partial responses (PR). Stable disease (SD) was observed in 40%. No patient had progressive disease (PD) preoperatively. With a median follow-up of 37 months, the median disease free survival (DFS) and median overall survival (OS) were 29 and 54 months, respectively. The actuarial 5-year DFS and OS were 36% and 49%, respectively. The locoregional recurrence rate was 20%, and 53% of the patients experienced systemic relapse. Univariate analysis revealed a significant prognostic difference according to clinical stage of LABC in favor of less advanced stages. Clinical and biologic parameters linked to a significantly worse prognosis were the presence of inflammatory breast carcinoma and peau d'orange. There was a significant trend of worse prognosis for patients receiving below 60% and 75% of the intended dose intensity with reference to DFS and OS, respectively. CONCLUSIONS: Standard dose preoperative and postoperative FEC therapy combined with surgery and radiotherapy in the era of mammography screening seem to yield results comparable to those achieved with other conventional strategies in the treatment of unscreened populations.     

Direct real time observation of base flipping by the EcoRI DNA methyltransferase

DNA methyltransferases are excellent prototypes for investigating DNA distortion and enzyme specificity because catalysis requires the extrahelical stabilization of the target base within the enzyme active site. The energetics and kinetics of base flipping by the EcoRI DNA methyltransferase were investigated by two methods. First, equilibrium dissociation constants (KDDNA) were determined for the binding of the methyltransferase to DNA containing abasic sites or base analogs incorporated at the target base. Consistent with a base flipping mechanism, tighter binding to oligonucleotides containing destabilized target base pairs was observed. Second, total intensity stopped flow fluorescence measurements of DNA containing 2-aminopurine allowed presteady-state real time observation of the base flipping transition. Following the rapid formation of an enzyme-DNA collision complex, a biphasic increase in total intensity was observed. The fast phase dominated the total intensity increase with a rate nearly identical to k(methylation) determined by rapid chemical quench-flow techniques (Reich, N. O., and Mashoon, N. (1993) J. Biol. Chem. 268, 9191-9193). The restacking of the extrahelical base also revealed biphasic kinetics with the recovered amplitudes from these off-rate experiments matching very closely to those observed during the base unstacking process. These results provide the first direct and continuous observation of base flipping and show that at least two distinct conformational transitions occurred at the flipped base subsequent to complex formation. Furthermore, our results suggest that the commitment to catalysis during the methylation of the target site is not determined at the level of the chemistry step but rather is mediated by prior intramolecular isomerization within the enzyme-DNA complex.