Study on Chrome-free Purging Plugs for Steel Ladles

Purging plug refractories in China typically contain around 3 mass% of super-fine chromium oxide in the matrix in order to improve the performance of the purging plugs, primarily, slag corrosion and wear resistance. Alternatives to chromium oxide containing refractories have gained interest due to health concerns related to the formation of soluble chromium compounds over long storage periods of refractory wastes. Super-ground reactive alumina can replace chromium oxide in purging plug refractories and this paper discussed the new reactive alumina E-SY 88 in comparison to chromium oxide in a typical purging plug castable. The mixing behaviour, wet castable properties, as well as cured, dried, and fired properties at different temperatures up to 1 600 ℃ were compared. In addition, the hot modulus of rupture, creep behaviour, thermal shock resistance and slag corrosion resistance were tested. The microstructure after slag corrosion was investigated by SEM. The results prove that E-SY 88 is an economically viable technical alternative to chromium oxide in purging plug refractories.

Effects of Nano-CaCO_(3)Addition on Properties of Corundum-based Dispersive Purging Plugs

In order to improve the properties of corundum based dispersive purging plugs,dispersive purging plug specimens were prepared using tabular corundum(1-0.15 and≤0.15 mm)as the aggregates,tabular corundum(≤0.044 mm)andα-Al_(2)O_(3)micropowder(d_(50)=0.6μm)as the matrix,Secar 71 cement as the binder,introducing different amounts of nano-CaCO_(3),casting into shapes,and firing at different temperatures(1200 or 1600℃)for 4 h.The effects of the nano-CaCO_(3) extra-addition(0,0.5%,1.0%,1.5%and 2.0%,by mass)on the consistency of the castables as well as the properties and microstructure of the dispersive purging plug specimens were studied.The results show that:(1)with the fixed water addition,the consistency of the corundum castables decreases as the nano-CaCO_(3)addition increases;(2)with the increasing nano-CaCO_(3)addition,the bulk density of the specimens fired at different temperatures for 4 h decreases,the apparent porosity,the cold strength and the hot modulus of rupture all increase,the gas permeability does not change significantly;(3)the specimens fired at 1600℃ for 4 h have obviously better cold comprehensive performance than those fired at 1200℃for 4 h;(4)when the nano-CaCO_(3)addition is 1.5%,the comprehensive performance of the specimen is the optimal.

Effects of Freeze/Thaw Cycles and Gas Purging Method on Polymer Electrolyte Membrane Fuel Cells

At subzero temperature, the startup capability and performance of polymer electrolyte membrane fuel cell (PEMFC) deteriorates markedly. The object of this work is to study the degradation mechanism of key components of PEMFC-membrane-electrode assembly (MEA) and seek feasible measures to avoid degradation. The effect of freeze/thaw cycles on the structure of MEA is investigated based on porosity and SEM measurement. The performance of a single cell was also tested before and after repetitious freeze/thaw cycles. The experimental results indicated that the performance of a PEMFC decreased along with the total operating time as well as the pore size distribution shifting and micro configuration changing. However, when the redundant water had been removed by gas purging, the performance of the PEMFC stack was almost resumed when it experienced again the same subzero temperature test. These results show that it is necessary to remove the water in PEMFCs to maintain stable performance under subzero temperature and gas purging is proved to be the effective operation.

Microstructure and physical properties of steel-ladle purging plug refractory materials

Three different castables were prepared as steel-ladle purging-plug refractory materials： corundum-based low-cement castable （C-LCC）, corundum-spinel-based low-cement castable （C-S-LCC）, and no-cement corundum-spinel castable （C-S-NCC） （hydratable alu- mina p-A1203 bonded）. The properties of these castables were characterized with regard to water demand/flow ability, cold crushing strength （CCS）, cold modulus of rupture （CMoR）, permanent linear change （PLC）, apparent porosity, and hot modulus of rupture （HMoR）. The re- sults show the CCS/CMoR and HMoR of C-LCC and C-S-LCC are greater than those of the castable C-S-NCC. According to the micro- structure analysis, the sintering effect and the bonding type of the matrix material differ among the three castables. The calcium hexaluminate （CA6） phase in the matrix of C-LCC enhances the cold and hot mechanical strengths. In the case of C-S-LCC, the CA6 and 2CaO·2MgO·14A12O3（C2MEA14） ternary phases generated from the matrix can greatly increase the cold and hot mechanical strengths. In the case of the no-cement castable, sintering becomes difficult, resulting in a lower mechanical strength.

PURGING OF BONE MARROWS CONTAMINATED WITH MYELOID LEUKEMIC CELLS BY INTERLEUKIN-2 AND LYMPHOKINE-ACTIVATED KILLER CELLS

The capability of recombinant human interleukin-2 ( rhIL-2) and lymphokine-activated killer (LAK) cells in the purging of normal human bone marrows contaminated with human myeloid leukemic cell lines was evaluated. Mixtures of normal human bone marrow mononuclear cells ( BMC) and K562 cells or HL-60 cells (at the BMCK562 ratio of 200:1, 100:1 or 20:1) were incubated with IL-2 with or without LAK cells at the BMC:LAK ratio of 1:1 for one or three days. The nubmers of residual K562 cells, BFU-E and CFU-GM were examined by clonogenic assays. In 200:1 mixture groups without LAK cells, the number of K562 colonies reduced by 50% with no loss of BFU-E and CFU-GM in one-day cultures, and no K562 colonies formed in three-day cultures with about 20% loss of BFU-E and CFU-GM. If the BMC.K562 ratios were 100:1 or 20:1 in the mktures, the leukemic cells could not be eliminated. When the mixtures were incubated with IL-2 and LAK cells, no leukemic cell colonies were detected in the 20:1 group following one-day

Numerical Simulation of Saline Intrusion and Purging in Long SeaOutfalls with Three-Dimensional Model

Saline intrusion into marine sewage ouffalls will greatly decrease the efficiency of sewage disposal. In order to investigate the mechanisms of this flow, in this paper, a three-dimensional numerical model based on FVM （Finite Volume Method） is established, The RNG κ-ε model is selected for turbulence modeling. The time-averaged vohtme fraction equations are introduced to simulate the stratification and inteffaeial exchange of sewage and seawater in outfalls. Validity of the established three-dimensional numerical model is evaluated by comparisons of numerical results with experimental data. With this three-dimensional numerical model, the internal flow characteristics in ouffalls for different sewage discharges are simulated. The results indicate that for a low sewage discharge, saline circulates in the outfall due to intrusion and both the inflowing momentum and the inteffaeial turbulent mixing are important mechanisms to extrude the saline. For a high sewage discharge, saline intrusion could be avoided. The inflow momentum is the main mechanism to extrude the saline and the inteffacial turbulent mixing is nut important relatively. Even at a high sewage discharge, the saline wedge would be retained in the main ouffall pipe after the risers are purged. It takes a long time for this saline wedge to be extruded by interracial turbulent mixing.

Progress and Developing Trend of Purging Plugs for Refining Ladle

Damage reasons of purging plugs for refining ladle and research progress on thermal shock resistance of corundum- spinel purging plugs were summarized. Research achievements and application results of nonoxides bonded corundum purging plugs for refining ladle were briefly reviewed. The further research and developing trend of purging plugs was proposed.

Hepatocytes isolated from neoplastic liver-immunomagnetic purging as a new source for transplantation

AIM： To investigate whether hepatocytes isolated from macroscopically normal liver during hepatic resection for neoplasia could provide a novel source of healthy hepatocytes, including the development of reliable protocols for malignant cells removal from the hepatocyte preparation. METHODS： Hepatocytes were procured from resected liver of 18 patients with liver tumors using optimised digestion and cell-enrichment protocols. Suspensions of various known quantities of the HT-29 tumor cell line and patient hepatocytes were treated or not with Ep-CAM-antibody-coated immunomagnetic beads in order to investigate the efficacy of tumor-purging by immunomagnetic depletion, using a semi-quantitative RT-PCR method developed to detect tumor cells. Immunomagnetic bead-treated or bead-untreated tumor cell-hepatocyte suspensions were transplanted intra-peritoneally in Balb/C nude mice to assess the rates of tumor development. RESULTS： Mean viable hepatocyte yield was 9.3×10^6 cells per gram of digested liver with mean viability of 70.5%. Immunomagnetic depletion removed tumor cells to below the RT-PCR detection-threshold of 1 tumor cell in 10^6 hepatocytes, representing a maximum tumor purging efficacy of greater than 400000-fold. Transplanted, immunomagnetic bead-purged tumor cell-hepatocyte suspensions did not form peritoneal tumors in Balb/C nude mice. Co-transplantation of hepatocytes with tumor cells did not increase tumorigenesis of the tumor cells. CONCLUSION： Immunomagnetic depletion appears to be an effective method of purging contaminating tumor cells to below threshold for likely tumorigenesis. Along with improved techniques for isolation of large numbers of viable hepatocytes, normal liver resected for neoplasia has potential as another clinically useful source of hepatocytes for transplantation.

PURGING OF ACUTE NON-LYMPHOCYTIC LEUKEMIA PROGENITORS BY PROCAINE AND HYPERTHERMIA

Procaine and hyperthermia have been shown to possess a relatively selective cytotoxicity to leukemlc cells. In this study, the combined effects of procaine and hyperthermia on the growth of hematopoietic progenitors (GM-CFU) and ieukemic progenitors (L-CFU) were examined to determine if this combination resulted in a great selective killing of leukemlc cells than that achieved by procaine or heat alone. When the cells were treated simutaneously with procaine (2 mM) and hyperthermia (42℃) for one hour, the killing of L-CFU was enhanced considerably whereas GM-CFU were not markedly affected. These data Indicate that the combined treatment with procain and hyperthermia might offer an efficient mean to selectively purge residual leukemlc cells in vitro. Procaine with hyperthermia may have a role in clinical autoiogous bone marrow transplantation for acute leukemia.

Optimization and Application of Corundum-spinel Purging Plugs for Refining Ladles

Corundum - spinel purging plugs were optimized through adjusting the formulation and the particle size composition of starting materials to prolong the service life of purging plugs for a 60 t refining ladle in a steel plant. Th.e optimized formulatioa is 30 mass% tabular corundum （6 - 3 mm ） , 20 mass% tabular corundum （3-1 ram）, 22 mass% tabular corundum （1 -0.5 ram） ＋ sintered spinel, 28% tabular corundum fines （0. 045 mm） ＋ fused spinel （0. 045 mm） ＋ bimodal α-Al2O3 micropowder ＋ Secar71 cement. The on-site results show that the plug can achieve an obviously long service life of 18 cycles, saving cost greatly.

Ongoing Technology and Developing Trend of Ar-blowing Purging Plug

An introduction of the ongoing technology of argon-blowing purging plugs in China was presented in this work. Gel powders were used as starting materials to enhance the high temperature mechanical properties of the purging plugs. Composite purging plug adopting extrusion formed gas-purging bar and slit had its surface structural design improved, which enhanced the resistances to thermal shock and molten steel penetration, prolonging the service life. In addition, the safety was greatly improved by upgrading the framework and production process, enhancing the resistance to breakout. It is indicated that the developing trend is to produce purging plugs of longer service life and better gas purging rate with different starting materials and structure designs to meet the requirements of various metallurgical processes.

Effects of Freeze/Thaw Cycles and Gas Purging Method on Polymer Electrolyte Membrane Fuel Cells

At subzero temperature, the startup capability and performance of polymer electrolyte membrane fuel cell PEMFC deteriorates markedly. The object of this work is to study the degradation mechanism of key compo- nents of PEMFC—membrane-electrode assembly MEA and seek feasible measures to avoid degradation. The ef- fect of freezethaw cycles on the structure of MEA is investigated based on porosity and SEM measurement. The performance of a single cell was also tested before and after repetitious freezethaw cycles. The experimental results indicated that the performance of a PEMFC decreased along with the total operating time as well as the pore size distribution shifting and micro configuration changing. However, when the redundant water had been removed by gas purging, the performance of the PEMFC stack was almost resumed when it experienced again the same subzero temperature test. These results show that it is necessary to remove the water in PEMFCs to maintain stable per- formance under subzero temperature and gas purging is proved to be the effective operation.

Purging Plugs and Well Blocks for Refining Ladle

1 Scope This standard specifies the classification, technical requirements, test methods, inspection rules, marking, packing, transportation, storage and quality certificate of purging plugs and well blocks for refining ladle.

手性分子构象分析装置圆二色光谱仪的加强与改造

圆二色光谱仪是对手性分子进行构象分析和理化性质表征的重要仪器.然而长期高强度的使用会产生光谱仪光学元件劣化、检测器灵敏度降低等问题.通过优化分光系统的光学元件提升光传输效率,升级具有更高量子效率的大面积雪崩硅光电二极管检测器,进而大幅提高仪器信噪比,同时将测量波长范围从175~900 nm扩展到175~1150 nm.在氙灯被点燃之前用氮气彻底净化仪器,把氧气排除在光谱仪之外是非常重要的操作步骤.安装具有监视、计划、流量设置、报警和辅助控制等功能的活性氮监测系统,可以实时监测控制仪器内部氮气吹扫情况.通过升级改造,既加强了仪器的性能,又节省了氮气消耗成本,同时仪器使用寿命将进一步延长.

不同贮藏温度及包装条件对乌天麻干片挥发性气味的影响

采用电子鼻及吹扫捕集-气相色谱-质谱联用技术(purgeand trap-gaschromatography-massspectrometry,PT-GC-MS)分析3个贮藏温度(10、25、40℃)及4种包装条件(空气、N_(2)、CO_(2)、脱氧)对乌天麻干片的挥发性气味的影响。结果表明:在120 d的贮藏期内,不同温度及包装下的乌天麻干片挥发性气味存在一定的差异。温度是影响贮藏期乌天麻干片挥发性气味最主要的因素,低温更有利于保持乌天麻干片挥发性成分。其次是包装条件,在同一温度条件下,脱氧处理更有利于保持乌天麻干片的挥发性气味。随着贮藏时间的延长,不同温度及包装条件下,乌天麻干片中挥发性物质在种类和含量上均发生变化,在120 d贮藏期内,10℃脱氧处理组共检测出挥发性成分29种,总含量为214.52μg/g,醇类占总挥发性成分的54%;酯类占总挥发性成分的14%;烷烃类占总挥发性成分的10%;与对照组的挥发性成分最为接近。综上所述,10℃脱氧包装为乌天麻干片最佳贮藏条件,在该条件下贮藏,乌天麻干片的风味成分损失最小,可在较长贮藏期内有效保留乌天麻干片的风味成分。

基于太阳病误下变证论“膈病”

太阳病涵盖了伤寒由表到里的整个演变过程,由于患者禀赋强弱、感邪轻重、就诊是否及时等原因,在此阶段可能出现表里证,所以太阳病可用到下法,但由于对表里先后顺序及整体病势把握不准确而误下产生变证者不少。太阳病下之后结局有两种:(1)下之愈。(2)下之不愈,而不愈者又可分为三种情况:一是误治后邪气仍在表者,当以汗解之;二是有表里证者,表解乃可攻里,否则引邪入里,为逆;三是误下影响了太阳病自然发展轨迹,导致表证几无,而邪气入膈,从而产生变证。无论太阳病正常转归还是误下发为变证,“膈”均是邪气入里之“首站”。膈病主要是邪气侵扰使其失去阻隔、分界作用,导致清浊易位,上下隔拒,典型特点为清浊不分,“上逆”与“下趋”症状并见,治疗首当察其在膈上、膈下,遵循“病在膈上必吐,在膈下必利”的治疗原则,观其脉证,随证治之。

升麻治疫思想探析

本文从阴阳毒、阴火、大气下陷等医论出发,探析不同医家运用升麻的治疫思想。升麻辛凉轻扬,可解百毒、辟障邪,多治温热疫、瘥后证。仲景以疫毒已发、未发之别区分阴阳毒,阳毒者,升麻合蜀椒、雄黄汗以发之、阴毒者,升麻合鳖甲解毒散结;李东垣则总以心火独盛为致疫关键,发于头面者,升麻合风类药、苦寒之品清热解毒、升阳泻火,脾胃内伤者,升麻合甘温补脾土之品以泻阴火;疹毒客于肺胃者,则以辛凉气轻之品为主,透疫达表、解毒去实;余邪搏击大气者,则循同气相求之理,升提大气,举陷托邪。

朝医补脾泻肾解郁法治疗少阴人中风后郁病气郁证临床观察

目的观察口服朝药十二味宽中汤配合朝医舍岩针法治疗少阴人中风后郁病气郁证的临床效果。方法按照随机数字表法将63例患者以单盲的原则分为治疗组、对照组,对照组31例给予口服盐酸帕罗西汀治疗,治疗组32例给予十二味宽中汤口服结合朝医舍岩针法针刺治疗,疗程1个月。将两组治疗前后汉密尔顿抑郁量表(HAMD)评分进行对比分析。结果治疗后,两组HAMD评分比较,差异有统计学意义(P<0.05)。治疗组总有效率为90.63%(29/32),高于对照组的74.19%(23/31)(P<0.05)。结论朝医补脾泻肾解郁法治疗少阴人中风后郁病气郁证有明显的临床效果,可显著提高治疗总有效率。

江泳教授病证结合分人分型分期辨治带状疱疹

带状疱疹以剧烈疼痛为其特点,严重影响患者生活。西医治疗虽起效较快但使疼痛降低至初始程度一半时较易产生不良反应,且在预防及控制其并发症方面效果不佳。江泳教授以病为纲,认为带状疱疹以肝络血虚,热毒湿浊瘀滞肝络为其共性核心病机,结合患者不同证型的个性病机进行分型论治。江教授以“柔肝泻火,解毒除湿,通络止痛”为基本治则,创制“泻毒通络”方为基础验方,分人分型分期加减治疗带状疱疹,她认为病证结合辨治带状疱疹,可以最大化地优化临床疗效,更能发挥中医特色优势。

升阳泻湿法治疗非酒精性脂肪性肝病初探

非酒精性脂肪性肝病是目前的多发病,为多因素所致,严重影响公共健康,目前对于该病的证治报道较多。该病的临床表现多数不典型,病机证候复杂,笔者汲取李东垣理论思想中升发脾之清气,以及黄元御理论思想中泻湿疏木的治法,把二者进行优化组合,拟定了升阳化湿,培土疏木为治疗大法运用于临床,立足于“湿”,分为“湿浊内蕴”和“脾虚湿困”2个证型,驭繁就简,取得了理想的临床疗效。