汽机满负荷下高压主汽门突关原因分析和处理

分析了某电厂4号机组满负荷试运期间,在LVDT次级线圈接线松动掉线后,TV1突然关闭的原因,并阐述了强制关闭GV1和GV3,减少TV1的前后差压,使TV1全开的处理过程。

1000MW火电机组单侧中调门突关的相关分析

控制油系统设备故障可能导致高中压主汽门、调门突关,同时引发EH母管油压降低,严重威胁机组安全。结合某公司1000 MW超超临界机组单侧中调门突关事故,分析异常原因,强调事故风险,梳理逻辑隐患,针对性提出处理要点与优化措施,为同类型机组事故处理及隐患排查提供借鉴意义。

火电厂机组汽门突关诊断分析

对某火电厂4号机组运行期间汽门突关进行全面分析和诊断测试,确定了DEH逻辑中复位电磁阀参数设置错误是造成机组汽门突关和机组跳闸的最主要原因,并给出了具体的防范措施。

巧用阀门活动试验解决主汽门突关

某台亚临界330MW汽轮机带负荷运行中,高压主汽门TV2开度突然由99%关闭到15.8%。通过对故障现象分析并逐一排查,在不危及机组安全运行的前提下用阀门活动试验把主汽门打开,恢复了汽轮机的正常运行模式,为排查问题赢得了宝贵的时间。可为快速、准确地解决类似汽轮机调门误动、拒动等故障提供参考。

汽轮机高压主汽阀运行中由全开突关的原因分析

针对 2 0 0 1年山西阳光发电有限责任公司 3号、 4号机运行中 2号高压主汽阀由全开突关的故障发生了 3次的问题。经分析确定为与主汽压力变化、阀门弹簧力。

腰椎板开窗半侧棘突关窗在腰椎手术中的应用

目的探讨腰椎板开窗半侧棘突关窗在腰椎手术中的意义。方法用椎板开窗半侧棘实关窗方法治疗腰间盘突出和马尾神经瘤,目的是保留部分椎板、全部棘突、棘上、棘间韧带等后柱结构,有效地保护了脊柱的稳定性,防止肌肉组织等与硬膜粘连。操作方法是,于腰椎板开窗2.0 cm×2.5 cm切除间盘,将棘突连同韧带与正中劈开,将其翻向开窗处关窗,将棘间韧带于关节突韧带缝合,再将关窗时取下的骨屑铺于棘突根部。结果用上述方法进行手术,术后随防没有发生滑椎现象,神经症状完全消失占80%,有轻微腿酸胀、麻木占15%,小腿仍有酸麻症状占3%,手术的优良率达96%以上。结论腰椎板开窗半侧棘突关窗对腰椎手术有较大优越性。

野三关隧道DK 124+602突水相关水文地质分析

研究目的:野三关隧道出口突发性大涌水,造成灾害。研究与分析施工资料、既有水文地质资料及现场观测资料,探究其原因,总结其规律,有效地确定其设计、施工整治方案,规避施工风险。研究结论:志留系碎屑岩组成的山地分水岭与栖霞组、茅口组灰岩组成的山地斜坡之间的地貌交界处和岩性界面处是汇水富集的地方;P1q+m富水地层中发育3#暗河,存在3个不同类型的充水层,它们都与3#暗河有不同程度的联系,隧道突水将暗河导入隧道;改道后的暗河继承、保留了原3#暗河的管道流特征、径流流量动态变化特征、降雨-流量关系特征等;暗河改道将对环境产生一定影响、大流量水流突出的泥石和随带的泥沙对施工和营运养护将造成困难。

颞骨关节后突的形态学研究

目的:研究颞骨关节后突的形态,提供解剖学资料,为临床参考。方法:观察和测量253例颅骨的颞骨关节后突,并进行分类。结果:颞骨关节后突的出现率为(95.65±1.28)％。依其形态分为结节型、锥体型、乳头型、平顶型和双峰型等五型,其中结节型占(76.86±2.71)％;依其高径分为大、中、小三型,其中中型占(57.02±3.18)％。结论:颞骨关节后突的出现率很高,以结节型为多见,其高径为2～8mm。颞骨关节后突的形态和高径与下颌头后移有关。

Impact analysis of supplier relationship on supply chain resilience using biological cellular resilience theory

A supply chain resilience model is established based on the biological cellular resilience theory to analyze the impact of the supplier relationship on supply chain resilience. A scenario where the market demand is changed suddenly by some undesired events is considered. The results reveal that enhancing collaboration with a more resilient supplier can significantly improve supply chain resilience and reduce supply chain losses. It is also found that enhancing the supplier relationship can significantly benefit supply chain resilience if the collaborative intensity is relatively low, and it has less effect if supply chain members have already collaborated closely. Thus, enhancing the supplier relationship to a limited intensity is a relatively effective and economic method to strengthen supply chain resilience.

Downscaling and Disaggregating NAO-conflict Nexus in Pre-industrial Europe

Recently, the desiccation effect of the North Atlantic Oscillation(NAO) is found to be positively correlated with violent conflict in pre-industrial Europe, with agricultural shrinkage and its subsequent economic shocks to be their causal link. However, it remains unexplored whether the correlation persists if the study period is extended backward in time, a different definition of violent conflict is applied, or the relationship is examined at lower geographic levels. In this study, we based on 835 internal disturbance incidents in Europe during 1049–1800 to conduct long-temporal and multi-scalar examination on the NAO-conflict nexus. ′Time-series′ and ′panel data′ disaggregation approaches, together with Granger Causality, Multiple Regression, and Survival Analyses were applied to verify the nexus quantitatively. Results show that the positive NAO-conflict correlation was significant at the continent and physiographic zone levels. During the positive NAO phases, the annual probability of internal disturbance outbreak increased by 70.0% in the southern Europe and the Mediterranean, a zone most affected by the NAO-induced desiccation effect. Yet, the NAO-conflict correlation was rather inconsistent when it was downscaled to the sub-regional level. Moreover, the NAO-conflict correlation was inflated under the time-series approach, while the panel data approach demonstrated the region-specific nature of the NAO forcing more clearly. The associated implications in examining climate-conflict nexus are discussed. Our findings may be crucial in examining violent conflict in the northwestern Africa, a highly agricultural region affected by the NAO.

Expression of mutant type-p53 products in H pylori-associated chronic gastritis

AIM： To investigate the mutation of p53 immunohistochemically in non-tumorous gastric mucosa with H pylori infection before and aEer H pylori eradication therapy. METHODS： 53 subjects （36 male, 17 female, mean age ± SEM, 57.1 ± 12.1） undergoing endoscopic examination were included in this study. 42 of 53 patients were H pylori-positive, and 11 were H pylorinegative. All H pylori-positive patients had successful eradication therapy. Biopsy specimens were taken from five points of the stomach, as recommended by the updated Sydney system. Immunohistochemical studies were performed by using primary antibodies against p53 （DO-7 and PAb240）. RESULTS： p53 （DO-7 and PAb240） immunoreactivity was shown in the neck region of the gastric pits, however, quite a few cells were found to be immunopositive for p53 （PAb240）in the Hpylori-infected gastric mucosa. The proportion of patients immunopositive for p53 （PAb240） was significantly reduced 6 mo after eradication [28/42 （66.7%） to 6/42 （14.3%）] （P 〈 0.05）, while the biopsies taken from H pylori-negative patients showed no immunoreactivity for p53 （PAb240）. p53 （PAb240）-positive patients were divided into two groups by the number of positive cells detected： one with more than six positive cells per 10 gastric pits （group A, n = 12）, and the other with less than five positive cells per 10 gastric pits （group B, n = 30）. Atrophy scores in group A were significant higher than those in group B at the greater curvature of the antrum （group A： 2.00 ± 0.14 vs group B： 1.40 ± 0.15, P = 0.012）, the lesser curvature of the corpus （group A： 2.00 ± 0.21 vs group B： 1.07 ± 0.23, P = 0.017）, and the greater curvature of the corpus （group A： 1.20 ± 0.30 vs group B： 0.47 ±0.21, P = 0.031）. Group A showed significant higher intestinal metaplasia scores than group B only at the lesser curvature of the antrum （group A： 2.10 ± 0.41 vs group B： 1.12 ± 0.29, P = 0.035）. CONCLUSION： H pylori-associated chronic gastritis expressed the mutant-type p53, which was significantly associated with more severe atrophic and metaplastic changes. Hpylori eradication led to a significant reduction in the expression of the mutant-type p53. It is considered that H pylori-infected chronic gastritis is associated with a genetic instability that leads to gastric carcinogenesis, and H pylori eradication may prevent gastric cancer.

On Tourism Development Modes of Intangible Cultural Heritage in China

How to conserve and develop the intangible cultural heritage is one of the hot topics in both tourism industry and academic research area. In the past, argument of conflict relationship between tourism and intangible cultural heritage has prevailed, however, more and more researches now question it. Based on the analysis of values and characteristics of intangible cultural heritage, this paper considers that the relationship can be beneficial to both with the appropriate and modest development, meanwhile, this paper summarizes seven tourism development modes, and at last it gives some advice on integrative adoption of those development modes after the thorough comparison of the seven modes.

Soviet Aid and the Construction of the Lanzhou Cyclotron

The transmission of science and technology from the Soviet Union to People’s Republic of China in the mid-twentieth century is an important research area of contemporary history of science and technology.This paper takes the construction of the cyclotron in Lanzhou,China as the case to discuss the characteristics of technology transfer from the Soviet Union to China.The review of extensive archives reveals that the construction of cyclotron took place in the framework of China’s nuclear weapons development.Although the transmission of science and technology from the Soviet Union to China fit into the one-way transmission-reception model in general,both the Chinese demand and the Soviet response had key influences on the transmission.In the early cyclotron construction,the Chinese side relied on the Soviets,and the mode of the cooperation between Soviet and Chinese engineers can be described as one of expertstudent.In the early 1960 s,the relationship between China and the Soviet Union broke down.The Soviet engineers were required to withdraw with the technical data,which created conflicts in the roles played by the Soviet engineers,most of whom chose to set the sense of professional responsibility as their highest priority.After the departure of the Soviet experts,Chinese physicists played the leading role in the project,using scientific knowledge they had,relying on the technical materials left by Soviet experts,and cooperating fully with local engineers,thus completing the cyclotron.This case can provide us with valuable clues for the understanding of transnational history of science and technology.The seemingly one-way transmission-reception model is actually influenced by the needs of both sides.While the transnational flow of knowledge is inevitably affected by political factors from both sides,the process is far more complex than it appears.

Causes and Ramifications of the Xinjiang july 2009 Disturbances

In July 2009, serious ethnic disturbances took place in 0r^imqi, the capital of Xinjiang, in China＇s north-west. Although open to diverse interpretations, they embodied serious conflicts between the Oighurs--the most populous ethnic group of Xinjiang--and China＇s dominant Han nationality. This article seeks to identify the causes of the disturbances, including both those internal to China and those external to it, both short-term and long-term. The issue is important, because Chinese official sources largely blamed outside terrorist and extremist forces, especially those associated with the main Uighur diaspora organizations, while the Uighur diaspora itself, largely supported by Western journalists and scholars, put the responsibility on the Chinese state, charging it with injustices against the Uighurs. This article contributes to the literature by finding both internal and external contributing factors. It also looks at the ramifications of the disturbances, including both the aftermath of the incidents and prospects for the future, and adopts a fairly pessimistic stance concerning short-term ethnic relations. The methodology is textual analysis and personal experience.

Characterization of a novel developmentally retarded mutant (drm1) associated with the autonomous flowering pathway in Arabidopsis

A developmentally retarded mutant (drm1) was identified from ethyl methanesulfonate (EMS)-mutagenized M2 seedsin Columbia (Col-0) genetic background. The drm1 flowers 109 d after sowing, with a whole life cycle of about 160 d.It also shows a pleiotropic phenotype, e.g., slow germination and lower germination rate, lower growth rate, curlingleaves and abnormal floral organs. The drm1 mutation was a single recessive nuclear mutation, which was mapped tothe bottom of chromosome 5 and located within a region of 20-30 kb around MXK3.1. There have been no mutantswith similar phenotypes reported in the literature, suggesting that DRM1 is a novel flowering promoting locus. Thefindings that the drm1 flowered lately under all photoperiod conditions and its late flowering phenotype was significantlyrestored by vernalization treatment suggest that the drm1 is a typical late flowering mutant and most likely associatedwith the autonomous flowering pathway. The conclusion was further confirmed by the revelation that the transcriptlevel of FLC was constantly upregulated in the drm1 at all the developmental phases examined, except for a very earlystage. Moreover, the transcript levels of two other important repressors, EMF and TFL1, were also upregulated in thedrm1, implying that the two repressors, along with FLC, seems to act in parallel pathways in the drm1 to regulateflowering as well as other aspects of floral development in a negatively additive way. This helps to explain why the drm1exhibits a much more severe late-flowering phenotype than most late-flowering mutants reported. It also implies that theDRM1 might act upstream of these repressors.

Relaxation Property and Stability Analysis of the Quasispecies Models

The relaxation property of both Eigen model and Crow-Kimura model with a single peak fitness landscape is studied from phase transition point of view. We first analyze the eigenvalue spectra of the replication mutation matrices. For sufficiently long sequences, the almost crossing point between the largest and seeond-largest eigenvalues locates the error threshold at which critical slowing down behavior appears. We calculate the critical exponent in the limit of infinite sequence lengths and compare it with the result from numerical curve fittings at sufficiently long sequences. We find that for both models the relaxation time diverges with exponent 1 at the error （mutation） threshold point. Results obtained from both methods agree quite well. From the unlimited correlation length feature, the first order phase transition is further confirmed. Finally with linear stability theory, we show that the two model systems are stable for all ranges of mutation rate. The Igigen model is asymptotically stable in terms of mutant classes, and the Crow-Kimura model is completely stable.

Switched-mode AGC circuits with internally created reset module for burst-mode unbalanced data optical receiver

This paper presents an innovative switched-mode auto gain control （AGC） circuit with internally created reset module for DC-10Mb/s burst-mode unbalanced （BMU） optical data transmission. Conventional AGC circuit is inappropriate for BMU data transmission because it is based on average level detection and requires considerable time to settle on a predefined gain. Therefore, we adopt a fast switched-mode AGC based on peak level detection. After the gain is adjusted, the peak level detectors need to re-detect the peak level of the input signal. Thus, we develop an internally created reset module. This AGC with reset module exhibits a fast operation and achieves an adjusted stable gain within one-bit, avoiding any bit loss up to 10Mb/s data rate. During power-up, the peak level detectors possibly hold an uncertain level resulting in the bit-errors. We propose a power-up reset circuit to solve this problem. Designed in a 0.5μm CMOS technology, the circuit achieves an optical sensitivity of better than -30dBm and a wide dynamic range of over 30dB with a power dissipation of only 30 mW from a 5V supply.

Research on Tourism Resources Development Pattern Effect Evaluation based on Regression Analysis and Neural Network

In this paper, we conduct research on the tourism resources development pattern effect evaluation based on regression analysis andneural network. Tourism resources development and the protection of all sorts of the contradictions, in the fi nal analysis is the confl ict betweenthe interests of stakeholders. Real life in China, and tourism resources development and protection of the interests of the relevant party basicallyhas the following six parties the local government, investment and the business practice, the original residents, tourists, tourism practitioners, thesocial organization. The survival and the development of general tourism industry is based on the premise of environmental protection, tourismlandscape are carefully protected, let the natural landscape and human landscape form a virtuous cycle, to attract more tourists, promote thesustainable development of scenic spots. Under this basis, this paper proposes the new idea on the issues that is meaningful.

Molecular mechanisms of ＂off-on switch＂ of activities of human IDH1 by tumor-associated mutation R132H

Human cytosolic NADP-1DH （IDH1） has recently been found to be involved in tumorigenesis. Notably, the tumorderived IDH1 mutations identified so far mainly occur at Arg132, and mutation R132H is the most prevalent one. This mutation impairs the oxidative IDH activity of the enzyme, but renders a new reduction function of converting a-ketoglutarate （aKG） to 2-hydroxyglutarate. Here, we report the structures of the R132H mutant IDH1 with and without isocitrate OCT） bound. The structural data together with mutagenesis and biochemical data reveal a previ- ously undefined initial ICT-binding state and demonstrate that IDH activity requires a conformational change to a closed pre-transition state. Arg132 plays multiple functional roles in the catalytic reaction; in particular, the R132H mutation hinders the conformational changes from the initial ICT-binding state to the pre-transition state, leading to the impairment of the IDH activity. Our results describe for the first time that there is an intermediate conformation that corresponds to an initial ICT-binding state and that the R132H mutation can trap the enzyme in this conforma- tion, therefore shedding fight on the molecular mechanism of the ＂off switch＂ of the potentially tumor-suppressive IDH activity. Furthermore, we proved the necessity of Tyr139 for the gained aKG reduction activity and propose that Tyr139 may play a vital role by compensating the increased negative charge on the C2 atom of aKG during the trans- fer of a hydride anion from NADPH to aKG, which provides new insights into the mechanism of the ＂on switch＂ of the hypothetically oncogenic reduction activity of IDH1 by this mutation.