600MW直接空冷机组凝结水精处理分床系统应用实例

随着北方地区水资源的日益紧缺,目前投产的大型火力发电机组逐渐开始以直接空冷为主,这就给整个汽水系统的净化处理装置——凝结水精处理的选型带来新的课题。直接空冷机组系统庞大、凝结水水温高,从设计选型上是选用分床系统还是树脂粉末过滤器,目前尚无定论。作者详细介绍了大唐国际托克托发电有限责任公司600 MW直接空冷机组的凝结水精处理设计、选型、运行的工作过程,为今后类似工程的设计、设备选型及运行方式提供了真实、可靠的实践经验。

超(超)临界机组凝结水精处理系统的方案配置

超(超)临界机组的汽水特性以及直流炉的结构决定了超(超)临界机组苛刻的水汽质量,因此对凝结水精处理系统的要求也更为严格。结合近期凝结水精处理技术的发展情况,针对1 000 MW级超超临界机组的几种凝结水精处理系统进行了详细阐述,提出各种精处理系统的适应范围及选择方法,同时指出了精处理技术需要进一步研究解决的问题。

Design of Moisture Control System for Beddings of Deep-litter

In order to solve the problems like rotten bed caused by accumulated wa-ter in the beddings of the deep-litter system, the ＂heat pulse method＂ was deter-mined as the moisture control method for beddings through tests, and a set of e-quipment was designed for the moisture control of deep-litter beddings. With STC89C52 micro-control er as the center, WL433A wireless communication module as means of data transmission, VB.NET for PC development, Access as back-ground database, the system realized the real-time col ection, wireless transmission, automatic storage and remote real-time monitoring of the internal information of the deep-litter beddings, which provided the facility basis for the research on the mois-ture control of deep-litter beddings, and to a certain extent, promoted the develop-ment of the facilities and equipment for livestock breeding.

Clinical analysis of multiple primary malignancies in the digestive system: A hospital-based study

AIM： To analyze the characteristics of multiple primary malignancies （MPMs） of digestive system; including incidence, types of tumor combinations, time intervals between development of multiple tumors, clinical course,and prognostic factors affecting survival and mortality.METHODS： Data from a total of 129 patients treated from January 1991 to December 2000 for pathologically proved MPMs, including at least one originating from the digestive system, were reviewed retrospectively.RESULTS： Among 129 patients, 120 （93.02%） had two primary cancers and 9 （6.98%） had three primary cancers. The major sites of MPMs of the digestive system were large intestine, stomach, and liver. Associated nondigestive cancers included 40 cases of gynecological cancers, of which 31 were carcinoma of cervix and 10 cases of genitourinary cancers, of which 5 were bladder cancers. Other cancers originated from the lung, breast,nasopharynx, larynx, thyroid, brain, muscle, and skin.Reproductive tract cancers, especially cervical, ovarian,bladder, and prostate cancers were the most commonlyassociated non-G! cancers, followed by cancer of the lung and breasts. Forty-three cases were synchronous, while the rest （86 cases） were metachronous cancers. Staging of MPMs and treatment regimes correlated with the prognosis between survival and non-survival groups.CONCLUSION： As advances in cancer therapy bring about a progressively larger percentage of long-term survivors, the proportion of patients with subsequent primary lesions will increase. Early diagnosis of these lesions, based on an awareness of the possibility of second and third cancers, and multidiscipiinary treatment strategies will substantially increase the survival of these patients.

Treatment of pancreatic pseu do cysts in line with D'Egidio's classification

AIM: To explore the implications of underlying diseases in treatment of pancreatic pseudocysts (PPC). METHODS: Clinical data of 73 cases of pancreatic pseudocyst treated in a 12-year period were reviewed comprehensively. Pancreatic pseudocysts were classified according to the etiological criteria proposed by D'Egidio. The correlation between the etiological classification, measure of treatment and clinical outcome of the patients was analyzed. RESULTS: According to the etiological criteria proposed by D'Egidio, 73 patients were divided into three groups. Group I was comprised of 37 patients with type I pseudocyst, percutaneous drainage was successful in the majority (9/11, 82%) while external or internal drainage was not satisfactory with a low success rate (8/16, 50%). Group II was comprised of 24 patients with type II pseudocyst, and internal drainage was curative for most of the cases (11/12, 92%), but the success rate of percutaneous or external drainage was unacceptably low (4/9, 44%). Group III consisted of 12 patients with type III pseudocyst. Internal drainage or pancreatic resection performed in 10 of these patients produced a curative rate of 80% (8/10) with the correction of the ductal pathology as a prerequisite. CONCLUSION: The classification of pancreatic pseudocyst based on its underlying diseases is meaningful for its management. Awareness of the underlying diseases of pancreatic pseudocyst and detection of the ductal pathology in type II and III pancreatic pseudocysts with endoscopic retrograde cholangiopancreatography may help make better decisions of treatment to reduce the rate of complications and recurrence.

Investigation on a vertical radial flow adsorber designed by a novel parallel connection method

Due to the increasing global demand for industrial gas, the development of large-scale cryogenic air separation systems has attracted considerable attention in recent years. Increasing the height of the adsorption bed in a vertical radial flow adsorber used in cryogenic air separation systems may efficiently increase the treatment capacity of the air in the adsorber. However, uniformity of the flow distribution of the air inside the adsorber would be deteriorated using the height-increasing method. In order to reduce the non-uniformity of the flow distribution caused by the excessive height of adsorption bed in a vertical radial flow adsorber, a novel parallel connection method is proposed in the present work. The experimental apparatus is designed and constructed; the Computational Fluid Dynamics(CFD) technique is used to develop a CFD-based model, which is used to analyze the flow distribution, the static pressure drop and the radial velocity in the newly designed adsorber. In addition, the geometric parameters of annular flow channels and the adsorption bed thickness of the upper unit in the parallelconnected vertical radial flow adsorber are optimized, so that the upper and lower adsorption units could be penetrated by air simultaneously. Comparisons are made between the height-increasing method and the parallel connection method with the same adsorber height. It is shown that using the parallel connection method could reduce the difference between the maximum and minimum radial static pressure drop by 86.2% and improve the uniformity by 80% compared with those of using the height-increasing method. The optimal thickness ratio of the upper and lower adsorption units is obtained as 0.966, in which case the upper and lower adsorption units could be penetrated by air simultaneously, so that the adsorbents in adsorption space could be used more efficiently.

T-cell ageing in end-stage renal disease patients:Assessment and clinical relevance

End-stage renal disease （ESRD） patients have a defec-tive T-cell-mediated immune system which is related to excessive premature ageing of the T-cell compartment. This is likely to be caused by the uremia-associated pro-infammatory milieu, created by loss of renal func-tion. Therefore, ESRD patients are highly susceptible for infections, have an increased risk for virus-associated cancers, respond poorly to vaccination and have an increased risk for atherosclerotic diseases. Three ageing parameters can be used to assess an immu-nological T-cell age. First, thymic output can be deter-mined by assessing the T-cell receptor excision circles-content together with CD31 expression within the na？ve T cells. Second, the telomere length of T cells and third the T-cell differentiation status are also indicators of T-cell ageing. Analyses based on these parameters in ESRD patients revealed that the immunological T-cell age is increased by on average 20 years compared to the chronological age. After kidney transplantation （KTx） the aged T-cell phenotype persists although the pro-inflammatory milieu is diminished. This might be explained by epigenetic modifcations at hematopoietic stem cells level. Assessment of an immunological T-cell age could be an important tool to identify KTx recipi-ents who are at risk for allograft rejection or to prevent over-immunosuppression.

Effect of urinary stone disease and its treatment on renal function

Urolithiasis is a common disease that affects urinary tract in all age groups. Both in adults and in children, stone size, location, renal anatomy, and other factors, can infuence the success of treatment modalities. Recently, there has been a great advancement in technology for minimally invasive management of urinary stones.The epoch of open treatment modalities has passed and currently there are much less invasive treatment approaches, such as percutaneous nephrolithotomy, ureteroscopy, shockwave lithotripsy, and retrograde internal Surgery. Furthermore, advancement in imaging technics ensures substantial knowledge that permit physician to decide the most convenient treatment method for the patient. Thus, effective and rapid treatment of urinary tract stones is substantial for the preservation of the renal function. In this review, the effects of the treatment options for urinary stones on renal function have been reviewed.

Hand Foot and Mouth Disease Due to Enterovirus 71 in Malaysia

Hand foot and mouth disease is a febrile sickness complex characterized by cutaneous eruption (exanthem) on the palms and soles with simultaneous occurrence of muco-cutanous vesiculo-ulcerative lesions (enanthem) affecting the mouth. The illness is caused by a number of enteroviruses with coxsackievirus A16 and enterovirus 71 as the main causative agents. Human enterovirus 71 (EV71) belongs to the species Human enterovirus A under the genus Enterovirus within the family Picornaviridae. EV71 has been associated with an array of clinical diseases including hand foot and mouth disease (HFMD), aseptic meningitis, encephalitis and poliomyelitis-like acute flaccid paralysis. A large outbreak of HFMD due to highly neurovirulent EV71 emerged in Malaysia in 1997, and caused 41 deaths amongst young children. In late 2000, a recurrence of an outbreak of HFMD occurred in Malaysia with 8 fatalities in peninsular Malaysia. Outbreak of HFMD due to EV71 recurred in 2003 with an unknown number of cases and mortalities. A similar outbreak of HFMD with 2 recorded deaths in young children occurred in peninsular Malaysia in late 2005 and this was followed by a larger outbreak in Sarawak (Malaysian Borneo) with 6 reported fatalities in the early part of 2006. The current on-going outbreak of HFMD started in peninsular Malaysia in epidemiological week 12 of 2010. As with other HFMD outbreaks in Malaysia, both EV71 and CA16 were the main aetiological viruses isolated. In similarity with the HFMD outbreak in 2005, the isolation of CA16 preceded the appearance of EV71. Based on the VP1 gene nucleotide sequences, 4 sub-genogroups of EV71 (C1, C2, B3 and B4) co-circulated and caused the outbreak of hand, foot and mouth disease in peninsular Malaysia in 1997. Two sub-genogroups (C1 and B4) were noted to cause the outbreak in 2000 in both peninsular Malaysia and Sarawak. EV71 of sub-genogroup B5 with smaller contribution from sub-genogroup C1 caused the outbreak in 2003. In the 2005 outbreak, besides the EV71 strains of sub-genogroup C1, EV71 strains belonging to sub-genogroup B5 were isolated but formed a cluster which was distinct from the EV71 strains from the sub-genogroup B5 isolated in 2003. The four EV71 strains isolated from clinical specimens of patients with hand, foot and mouth disease in the Sarawak outbreak in early 2006 also belonged to sub-genogroup B5. Phylogenetic analysis of the VP1 gene suggests that the EV71 strains causing the outbreak in Sarawak could have originated from peninsular Malaysia. Epidemiological and molecular data since 1997 show the recurrence of HFMD due to EV71 in Malaysia every 2 to 4 years. In each of the past outbreaks, more than one sub-genogroup of the virus co-circulate.

Classification of epilepsy using computational intelligence techniques

This paper deals with a real-life application of epilepsy classification, where three phases of absence seizure, namely pre-seizure, seizure and seizure-free, are classified using real clinical data. Artificial neural network （ANN） and support vector machines （SVMs） combined with su- pervised learning algorithms, and k-means clustering （k-MC） combined with unsupervised techniques are employed to classify the three seizure phases. Different techniques to combine binary SVMs, namely One Vs One （OvO）, One Vs All （OVA） and Binary Decision Tree （BDT）, are employed for multiclass classification. Comparisons are performed with two traditional classification methods, namely, k-Nearest Neighbour （k- NN） and Naive Bayes classifier. It is concluded that SVM-based classifiers outperform the traditional ones in terms of recognition accuracy and robustness property when the original clinical data is distorted with noise. Furthermore, SVM-based classifier with OvO provides the highest recognition accuracy, whereas ANN-based classifier overtakes by demonstrating maximum accuracy in the presence of noise.

Update on risk scoring systems for patients with upper gastrointestinal haemorrhage

Upper gastrointestinal haemorrhage (UGIH) remains a common medical emergency worldwide. It is increasingly recognised that early risk assessment is an important part of management, which helps direct appropriate patient care and the timing of endoscopy. Several risk scores have been developed, most of which include endoscopic findings, although a minority do not. These scores were developed to identify various end-points including mortality, rebleeding or clinical intervention in the form of transfusion, endoscopic therapy or surgery. Recent studies have reported accurate identification of a very low risk group on presentation, using scores which require simple clinical or laboratory parameters only. This group may not require admission, but could be managed with early out-patient endoscopy. This article aims to describe the existing pre- and post-endoscopy risk scores for UGIH and assess the published data comparing them in the prediction of outcome. Recent data assessing their use in clinical practice, in particular the early identification of low-risk patients, are also discussed.

Industrial-scale Fixed-bed Coal Gasification: Modeling, Simulation and Thermodynamic Analysis

We have developed a process model to simulate the behavior of an industrial-scale pressurized Lurgi fixed-bed coal gasifier using Aspen Plus and General Algebraic Modeling System(GAMS). Reaction characteristics in the fixed-bed gasifier comprising four sequential reaction zones—drying, pyrolysis, combustion and gasification are respectively modeled. A non-linear programming(NLP) model is developed for the pyrolysis zone to estimate the products composition which includes char, coal gases and distillable liquids. A four-stage model with restricted equilibrium temperature is used to study the thermodynamic equilibrium characteristics and calculate the composition of syngas in the combustion and gasification zones. The thermodynamic analysis shows that the exergetic efficiency of the fixed-bed gasifier is mainly determined by the oxygen/coal ratio. The exergetic efficiency of the process will reach an optimum value of 78.3% when the oxygen/coal and steam/coal mass ratios are 0.14 and 0.80, respectively.

Study on mixing and segregation behaviors in particulate fluidized bed system for mineral processing

In order to identify the mixing and segregation behaviors in a mineral processing operation, present study aimed on the hydrodynamics of solid–liquid fluidization. The study was carried out in a fluidization column with tapings at different height of the bed to collect the sample. The binary particles considered in this study are hematite(4800 kg/m3) and quartz(2600 kg/m3) at different size fractions in the range of average size 87×10^(-6)m to 400×10^(-6)m. It is observed that for various binary mixtures, both quartz and hematite particles share the equal composition by mass(50%) at a particular height of fluidized bed, referred as ‘‘locus point'' of mixing. Study indicates that the mixing zone volume will increase for a continuous fluidized bed plant operation. It is observed that the number of locus points varies from 1 to 3 signifying their dependency on the size ratios of binary mixture. Whenever, the difference in terminal velocity between quartz and hematite particles approaches to zero, mixing is enhanced.Further, the present study is extended to find the segregation index for the different size ratios of quartz and hematite particles. It is evident that depending on the size ratios, various regions such as complete segregation, partial mixing and complete mixing can be observed.

Long-term potentiation in autonomic ganglia:Potential role in cardiovascular disorders

Ganglionic long-term potentiation(gLTP) is an activitydependent,enduring enhancement of ganglionic transmission.This phenomenon may be induced in autonomic ganglia of an organism under certain conditions whererepetitive impulses surge from the central nervous system(CNS) to the periphery.Chronic stress,repetitive epileptic seizure or chronic use of CNS stimulants could induce gL TP,which would result in a long lasting heightening of sympathetic tone to the cardiovascular system causing hypertension and disturbed cardiac rhythm that may lead to sudden cardiac death.These conditions are briefly reviewed in this article.

PET for Staging of Esophageal Cancer

FDG-PET is of clinical value especially for detection of distant metastases or recurrent esophageal cancer. For the staging of primary tumor or locoregional lymph node metastasis PET is cur- rently not suitable.

Drug delivery in ocular diseases: Barriers and strategies

The eye is a complex organ made up of diversifed cells with specifed functions. Presence of anatomical, physi-ological and physiochemical barriers make it diffcult to deliver drugs in therapeutic amounts at intended sites. To overcome these, drug delivery scientists have fol-lowed two distinct yet complimentary approaches. The frst involves using alternate delivery routes to conven-tional ones allowing for more direct access to intended target sites. Second approach involves development of novel drug delivery systems providing better perme-ability, treatability and controlled release at target site. Combination of both these approaches are being uti-lized and optimized in order to achieve optimal therapy with minimal adverse effects.

High altitude headache occurs frequently among construction workers in Yushu

The aim was to measure the incidence of high altitude headache （HAH） and to determine clinical features, as well as the relation between acute mountain sickness （AMS） and HAH through a prospective study. We conducted a questionnaire-based study among construction workers in Yushu after a serious earthquake ; they were under reconstruction using a structured questionnaire incorporating International Headache Society （IHS） and AMS Lake Louise Scoring System. A total of 608 workers were enrolled after their first ascent to altitudes of 3 750-4 528 m. The results showed that 96 % reported at least 1 HAil（median 3.8, range from 1 to 10） in workers at a mean altitude of 4 250 m. The magnitude of headache was divided as mild（38 %）, moderate （44 % ） and severe （18 %）. This study indicates that HAH is the most common symptom of acute altitude exposure and closely corre- lated with altitude （r=0.165, p〈0.001）. However, 52 % of headache was one of the main symptoms of AMS, while the other 48 % was the sole symptom of HAH. On the contrary we found that 2 % of AMS without headache, thus the ＂painless AMS＂ actually existed. The clinical features of HAH are presented, and the relationship between AMS and HAH is discussed.

The expression and clinical significance of KAI1 and CD44v6 protein in human osteosarcoma

Objective:To investigate the expressions of KAI1 and CD44v6 in human osteosarcoma and the relationship between expressions of them and their clinic pathological features and prognosis.Methods:The expressions of KAI1 and CD44v6 in 87 samples with osteosarcoma were detected by S-P immunohistochemistry.Results:Expression of KAI1 had correlation with metastasis of osteosarcoma,and was strongly associated with differentiation of tumor cells.The expression of CD44v6 in osteosarcoma had correlation with metastasis.There was no difference between the expression of KAI1 and CD44v6.Cox model analysis showed that the prognostic factors were KAI1 expression,metastasis and Enneking surgical staging system.Conclusion:The abnormal expression of KAI1 and CD44v6 participate metastasis of osteosarcoma,KAI1 expression,metastasis and Enneking surgical staging system can be used to independently predict the prognosis of osteo-sarcoma patients.

Clinical analysis of primary central nervous system lymphoma with non-immune deficiency in 17 patients

Objective: The aim of this study was to investigate the clinical manifestations of primary central nervous system lymphoma (PCNSL) with non-immune deficiency and explore effective methods for its diagnosis and treatment. Methods: The clinical, imaging and pathological data from 17 cases with PCNSL in our hospital from March 2006 to April 2009 were analyzed. The immunologic function test for all 17 cases was confirmed as normal. Four of them received stereotactie brain biopsy while the other patients were given full or partial resection. Fifteen of them were given both radiotherapy and chemotherapy after surgery. High-dose Methotrexate (HD-MTX) (2.0g/m2) was used via intravenous infusion once per week for three times. From week 4, patients began radiotherapy. Six cases with abnormal cerebrospinal fluid were given whole central nervous system radiotherapy, and 9 cases with normal cerebrospinal fluid were given only whole brain radiotherapy. Two of them were without any additional treatment after surgery. Sixteen of 17 cases were followed up for 9-48 months. Therapeutic efficacy, toxic and side effect were investigated. Results: Six cases, who were given HD-MTX chemotherapy and whole central nervous system radiotherapy, had grade 3 leukopenia, but other toxic and side effect above grade 3 were not observed. Two patients having no chemotherapy and radiotherapy recurred in one month, but there was only one recurred case in three months among 15 cases who had both chemotherapy and radiotherapy. One of them lost fellow-up. The 2-year survival rate was 69.2%. Conclusion: There is no specific clinical manifestation for PCNSL. The pathological examination is a reliable method to confirm PCNSL. Recurrence may occur after surgery alone, however, the combination of HD-MTX chemotherapy and radiotherapy is an effective and safe therapeutic option, which might improve the treatment efficiency and survival rate.

Percutaneous pedicle screw fixation through the pedicle of fractured vertebra in the treatment of type A thoracolumbar fractures using Sextant system： an analysis of 38 cases

Objective： To prospectively evaluate the feasibility, safety and efficacy of the percutaneous pedicle screw fixation through the pedicle of fractured vertebra in the treatment of type A thoracolumbar fractures using Sextant system in the retrospective non-randomized case-control study. Methods： Atotal of 38 consecutive non-randomized patients with type A thoracolumbar fractures, which had been stabilized posteriorly from December 2006 to March 2009, were examined retrospectively more than 9 months after surgery. Twenty-one patients had been treated conventionally with open pedicle screw fixation （OPSF） and 17 patients received minimally invasive treatment with Sextant percutaneous pedicle screw fixation （SPPSF）. As a method of evaluation, the incision size, the intraoperation and post- operative volume of blood loss, operation time, postoperative hospital stay, blood transfusion, the radiological assessment of the sagittal Cobb＇s angle, vertebral body angle and vertebral body height were recorded and compared. Results： All patients were followed up for 8-24 months （average 11.6 months）. There were significant differences in the incision size, surgical blood loss, surgical draining Joss, operation time, hospital stay after operation, blood transfusion, the proportion of antalgic supplement and postoperative incisional VAS between the two groups （P〈0.05）. Mean preoperative kyphotic deformity was 16.0° and improved by 9.3° after surgery in OPSF group, but 15.2° and 10.3° respectively in SPPSF group. Mean preoperative angle of the fractured vertebral body was 15.9°and improved by 7.9° after surgery in OPSF group, but 14.9° and 6.6° respectively in SPPSF group. Mean anterior vertebral body height （% of normal） was 67.3% before surgery and 95.8% after surgery, but 69.1% and 90.1% respectively in SPPSF group. Mean posterior vertebral body height （% of normal） was 93.3% before surgery and 99.5% after surgery, but 88.9% and 93.3% respectively in SPPSF group. Among the patients whose 9-month follow-up films were available, 3.0° ofkyphosis correction was lost in OPSF group, but 3.2° in SPPSF group. And 1.0°of the angle of the fractured vertebral body correction was lost in OPSF group, but 1.5°in SPPSF group. Then 3.0% of the anterior vertebral body height correction was lost in OPSF group, but 2.2% in SPPSF group. And 3.0% of the posterior vertebral body height correction was lost in OPSF group, but 2.5% in SPPSF group. The sagittal Cobb＇s angle, vertebral body angle and anterior height of the fractured vertebra were all significantly different in each group before and after operation （P〈0.05）. There were no significant differences in the postoperative sagittal Cobb＇s angle, vertebral body angle and the improvement of the vertebral body height and the kyphotic deformity correction between OPSF and SPPSF groups （P〉0.05）, but there was significant difference in the postoperative anterior height of the fractured vertebra between the two groups （P〈0.05）. Conclusion： The percutaneous pedicle screw fixation through the pedicle of fractured vertebra using Sextant system is a good minimally-invasive surgical therapeutic choice for patients with type A thoracolumbar fracture except for that the SPPSF has a little insufficiency in resuming the anterior height of the fractured vertebra compared with OPSF.