130 t/h燃煤锅炉应用单/双燃烧介质的技术改造

文章介绍了燃煤锅炉改全烧和部分掺烧焦炉煤气锅炉的工艺可行性和原理,并结合130 t/h燃煤锅炉具体改造实践,简要地介绍了改造方案和主要改造的设备及装置,取得了良好的经济效益和社会效益,具有一定的推广应用价值.     

韶钢2号锅炉煤气综合利用升级改造

为解决煤气富余问题,韶钢对发电工段2号锅炉进行煤气化改造。该锅炉原来以烧煤为主掺烧部分焦炉煤气,通过对锅炉等进行改造,实现了以高炉煤气和焦炉煤气为燃料,有效解决了煤气富余的问题     

炼油企业锅炉掺烧石油焦炉型选择

就炼油企业锅炉掺烧石油焦炉型选择问题，从燃料适应性、热负荷调节适应性、环境保护、初期投资几个方面对煤粉锅炉和循环流化床锅炉两种炉型进行了分析比较。并结合国内的实际情况，认为炼油企业锅炉掺烧石油焦采用循环流化床锅炉是可靠的。如对该炉型进行相应的技术改造，燃料全部采用石油焦在技术上也是可行的。     

掺烧工业固废150 t/h循环流化床锅炉的设计

设计循环流化床锅炉时,针对锅炉参数、设计煤种选取合理的流化状态,考虑掺烧带来的相关问题,并针对这些问题在设计时做出相应改进,最终保证所设计的循环流化床锅炉能够环保、高效、经济的运行。     

燃机余热锅炉运行调整分析

燃气-蒸汽联合循环发电机组为燃高炉煤气掺烧焦炉煤气的低热值联合循环发电机组,对以低热值高炉煤气为主要燃料的燃气-蒸汽联合循环发电机组的余热锅炉运行调整,进行分析、调整,使燃机余热锅炉运行、合理、安全、稳定。     

链条炉改造煤——煤气混燃的流化床锅炉的实践

将链条锅炉改造成以煤矸石和煤气(焦炉煤气和高炉煤气)为燃料的低速、低循环倍率流化床锅炉,将焦铁企业洗选剩下的煤矸石、炼焦炉排放出来的焦炉煤气和炼铁炉排放出来的高炉煤气用于流化床锅炉发电以供给炼铁高炉风机等用电设备使用;锅炉排出的冷渣、飞灰收集起来作为生产水泥和矸石砖的原料,实现了节能减排和资源的综合利用。     

能源公司动力1号锅炉高炉煤气燃烧器改造

介绍了220t／h掺烧高炉煤气的煤粉锅炉的高煤燃烧器改造。锅炉原设计以焦炉煤气点火，采用煤粉升负荷，锅炉燃烧稳定后投入高煤，但是存在锅炉在点火过程中锅炉后部烟道积水、影响电除尘器的投运、高炉稳定掺烧量达不到要求等问题。针对上述问题，对原有的高煤管式燃烧器进行了改造，优化了管式高煤的燃烧特性，实现了通过焦煤引燃高煤，以高煤来升炉升压，提高了高煤的使用量，降低了动力生产成本。     

煤气锅炉空气预热器腐蚀原因及对策

结合对75t煤气锅炉低温段空气预热器的改造实例,阐述了煤气锅炉低温段空气预热器因锅炉负荷变化、掺烧焦炉煤气增大等因素而引起的低温段空气预热器低温腐蚀现象,分析了低温段空气预热器腐蚀损坏的原因并提出了相应的预防改进措施。     

220t/h煤粉锅炉改造为纯烧高炉煤气的技术措施

包钢热电厂220t/h高温高压锅炉由燃煤掺烧高炉煤气改造成纯烧高炉煤气，介绍了稳燃柱技术在高温高压锅炉改造中的优势，锅炉改造的范围以及效益分析。     

低氮燃烧在大比例掺烧焦炉煤气煤粉锅炉上的应用

低氮燃烧技术已经成为燃煤电站锅炉常用脱硝辅助手段,通过分级送入分离式燃尽风,在燃尽区形成NOx控制,以零运行成本实现NOx大幅度减排。由于运行稳定,技术成熟,因此被广泛使用。但对于大比例掺烧焦炉煤气煤粉锅炉而言,焦炉煤气烧嘴布置形式对低氮燃烧影响较大,布置不当会对锅炉运行稳定性和经济性产生不利影响。     

Effects of locally administered prostaglandin E1 on anterior hypothalamic neurons

Shifts in the displayed shades of gray were found in the initial evaluation of a gray scale ultrasound display. Quantitative measurements of these shifts were performed. These measurements, along with measurements of scan converter output and photographic exposure time, established television (TV) performance as the major cause of shifts. Random variations in photographic exposure time were shown to cause small random shifts. Recommendations are given to minimize the effects of these shifts in clinical sonograms. To minimize shifts, hardware modifications were made on a similar TV. These modifications substantially improved the TV performance.     

Changes in stiffness induced by hindlimb suspension in rat soleus muscle

Soleus muscle atrophy was induced by hind-limb suspension of rats for 3 weeks with the intention of inducing a relative increase in the percentage of fast-twitch fibres and assessing modifications in muscle stiffness. A method of dual controlled releases was used to obtain tension/extension curves and force/velocity relationships characterizing the mechanical behaviour of the soleus. Fibre typing was achieved by myofibrillar adenosine 5'-triphosphatase staining. Results showed that hindlimb suspension decreased the percentage of slow-twitch fibres (-31%) to the profit of fast-twitch fibres (+370%) and intermediate fibres (+255%). This led to an increase in maximal shortening velocity. Tension/extension curves indicated a decrease in soleus stiffness after 3 weeks of unloading. Changes in elastic properties are interpreted in terms of modifications occurring in the active part and the passive part of the so-called series elastic component. These changes also suggest that the parameters derived from a twitch are inappropriate to account for modifications in speed-related properties of muscle.     

Parallel coding of conjunctions in visual search

The microtubule associated protein tau is the main structural component of paired helical filaments (PHFs), aberrant polymers found intracellularly in neurons of brains with the Alzheimer's disease. Glycation is one of the posttranslational modifications that has been found in tau from PHFs, but not in normal brain tau. Studies were carried out with purified tau protein subjected to chemical modifications, in order to further investigate the mechanisms of tau self-association into PHFs. Tau was subjected to modifications affecting reactive lysyl residues, e.g., carbamoylation with potassium cyanate and glycation reaction with glucose. The effects of these modifications to produce functional alterations in tau capacity to bind brain tubulin and to induce microtubule assembly were investigated. Chemically-modified tau and tau of Alzheimer's type exhibited a similar microtubule interaction behavior as analysed by overlay assays, but those were different than normal tau controls. On the other hand, studies of the microtubule assembly kinetics indicated that the reported tau modifications resulted in a loss of its capacity to promote microtubule assembly from purified tubulin preparations. The data on the differences in the electrophoretic profiles, Western blots and the overlay patterns, along with those on the microtubule polymerisation of normal brain tau as compared with both modified and Alzheimer's tau, suggest changes in the functional behavior of this protein as a result of its structural modifications. These studies were complemented with an immunogold analysis at the electron microscope level, which indicated that the modified tau did not incorporate into assembled microtubules. These findings, combined with the results on tau chemical modifications suggest that the reactive lysine residues within functional domains on tau, e.g., those of the repetitive binding motifs, were affected by these modifications. Furthermore, these observations provide new clues to understand the anomalous interactions of tau in Alzheimer's disease.     

Mechanisms of aging of the extracellular matrix: role of the elastin-laminin receptor

Aging of connective tissues is important for the understanding of aging mechanisms of tissues rich in extracellular matrix and of age-dependent diseases often affecting such tissues. Aging mechanisms of such tissues can be divided as follows: (1) age-dependent modifications of matrix biosynthesis; (2) postsynthetic modifications of extracellular matrix, and (3) modifications of cell-matrix interactions. Examples are discussed for all three aspects of tissue aging, with special emphasis on the role of epigenetic reactions. These reactions include the Maillard reaction, uncontrolled proteolytic degradation, and free radical release. Proteolytic fragments of fibronectin and of elastic fibers were shown to produce noxious effects and to be engaged in vicious circles of autoentertained and self-amplified mechanisms. We studied in particular the role of the elastin-laminin receptor in tissue aging and in atherogenesis. The presence of saturating concentrations of elastin peptides in the circulation results in a chronic overstimulation of the receptor with sustained free radical and lytic enzyme production. Other examples of age-dependent uncoupling of receptors also illustrate the importance of altered receptor function in tissue aging and related pathologies.     

Signalling functions of protein palmitoylation

Covalent lipid modifications anchor numerous signalling proteins to the cytoplasmic face of the plasma membrane. These modifications mediate protein-membrane and protein-protein interactions and are often essential for function. Protein palmitoylation, due to its reversible nature, may be particularly important for modulating protein function during cycles of activation and deactivation. Despite intense investigation, the exact functions of protein palmitoylation are not well understood. However, it is clear that palmitoylation can affect a protein's affinity for membranes, subcellular localization, and interactions with other proteins. In this review, recent advances in understanding the functions and mechanisms of protein palmitoylation are discussed, with particular emphasis on how this lipid affects the biochemistry and cell biology of signalling proteins.     

Model modifications in covariance structure analysis: The problem of capitalization on chance.

In applications of covariance structure modeling in which an initial model does not fit sample data well, it has become common practice to modify that model to improve its fit. Because this process is data driven, it is inherently susceptible to capitalization on chance characteristics of the data, thus raising the question of whether model modifications generalize to other samples or to the population. This issue is discussed in detail and is explored empirically through sampling studies using 2 large sets of data. Results demonstrate that over repeated samples, model modifications may be very inconsistent and cross-validation results may behave erratically. These findings lead to skepticism about generalizability of models resulting from data-driven modifications of an initial model. The use of alternative a priori models is recommended as a preferred strategy. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Transmission FT-IR microspectroscopy of mineral phases in calcified tissues

Fourier-transform infrared microspectroscopy (FT-IRM) was used to study bone mineralization processes in an in vivo model and in enamel in osteogenesis imperfecta. Finally, the ability of FT-IRM to map new bone formed in implanted macroporous calcium phosphate biomaterial from sections was reported for the first time. FT-IRM allowed the correlation of the microstructure of bone formation in the in vivo model with modifications in carbonate and phosphate environments of the mineral phases during maturation. FR-IRM analysis on enamel sections revealed changes in the mineral environment of carbonate and phosphate ions and probably in the size of enamel crystals. These modifications contributed to the fragility of enamel in osteogenesis imperfecta. The infrared functional group imaging of a part of implanted biomaterial and the bone ingrowth provided the visualization of chemical modifications occurring in biomaterial implants at 20 microns spatial resolution. The use of FT-IRM, in conjunction with appropriate sampling methods and data analysis should provide further insight into the molecular structure of mineral phases of calcified tissues and help to elucidate mineralization processes, skeletal disorders and properties of the biomaterials used as bone substitute.     

Anthracycline doses in patients with liver dysfunction: do UK oncologists follow current recommendations?

The question of whether UK oncologists follow current anthracycline dose modifications when treating patients with liver dysfunction was addressed through a questionnaire. Oncologists were asked the dose of doxorubicin or epirubicin they would prescribe for a woman with breast cancer and liver metastases who had one of four different patterns of abnormal liver chemistry. In each case, the median dose of anthracycline that would have been prescribed was close to that currently recommended. There was, however, wide variation in the dose that oncologists said they would prescribe, some avoiding an anthracycline altogether, whereas others would give full-dose treatment. Medical oncologists would prescribe a significantly lower dose of anthracycline than clinical oncologists for a patient with the most severely disturbed liver tests. Overall, medical oncologists were also significantly more likely to prescribe epirubicin. These results show the need for new, widely accepted anthracycline dose modifications for patients with liver dysfunction.     

Reviving the diagnosis of neurasthenia

We demonstrate that post-translational bromination of a tryptophan residue occurs in the biologically active octapeptide bromocontryphan, purified and characterized from Conus radiatus venom. Clones encoding bromocontryphan were identified from a cDNA library made from C. radiatus venom ducts. The mRNA sequence obtained predicts a prepropeptide which has the mature peptide sequence at the C-terminal end, with the L-6-bromotryptophan residue encoded by UGG, the Trp codon. These data provide the first direct evidence for post-translational bromination of a polypeptide which is translated through the normal cellular machinery. In addition to bromination, the peptide, which induces a "stiff tail" syndrome in mice, has several other modifications as shown by the sequence [Formula: See Text] in which Hyp = hydroxyproline. Asterisks indicate post-translational modifications (left to right): proteolytic cleavage at the N-terminus; hydroxylation of Pro3; epimerization of Trp4; bromination of Trp7, and C-terminal amidation. Bromocontryphan appears to have the highest density of post-translational modifications known among gene-encoded polypeptides. The overall result is a molecule which closely resembles marine natural products produced through specialized biosynthetic pathways comprising many enzyme-catalyzed steps.     

Cobalamin analogues modulate the growth of leukemia cells in vitro

Analogues of cyanocobalamin (CN-Cbl), with functional groups attached to either the various propionamide groups of the corrin ring or to the ribose-nucleotide linker arm, have been evaluated in a cobalamin (Cbl)-dependent in vitro cell growth assay. In this bioassay, CN-Cbl supported, in a dose-dependent manner, the growth of the murine lymphoma BW5147 and the Cbl carrier protein, human apo-transcobalamin II, reduced the required concentration of Cbl by 100-1000-fold. Any chemical modification of Cbl decreased its ability to support cellular viability and proliferation, with several of the modifications abrogating activity completely. All of the Cbl analogues that promoted growth required the presence of apo-transcobalamin II for the optimal support of cell growth. Generally, Cbl analogues modified at the d-position of the corrin ring and, to a lesser degree, analogues modified at the b- position supported cell growth, whereas analogues with modifications at the e-position did not support cell growth. Mixing experiments demonstrated an inverse order of potency of Cbl analogues to inhibit cell growth. Thus, Cbl analogues with modifications at the e-position were potent inhibitors, whereas b-analogues exhibited only partial inhibitory activity at high molar excess, and d-analogues had no inhibitory activity at all. These results indicate that modifications at the e-position of Cbl abolish the ability of Cbl to support cell growth and generate potent inhibitors of Cbl-dependent cell growth.