大型制冷机组的冲洗与调试

大型制冷机组部件众多，管路比较复杂，又是必须承受高压的容器，安装、调试都有严格的要求。以30HXC165A制冷机组的现场冲洗、调试为例，详细介绍了大型制冷机组在试运行之前标准的准备工作。这些工作包括吹扫、试压、排污、充注制冷剂和冲洗调试等全部过程及注意事项。本文为大型螺杆式制冷机组这种压力容器设备的运行和维护管理提供了工程实践经验。结果表明：在施工调试过程中，只有各方互相协调，并且严格按照相关文件和规范要求才能顺利完成制冷机组的安装调试，为以后的正常运行打下基础。

称重式蒸渗仪系统改进及在农田蒸散研究中的应用

水分是制约黄土丘陵区农作物正常生长和农业生产的关键因子。该区年平均降水量少且季节多变,研究农田土壤水分平衡对该区旱地农业生产具有重要意义。土壤蒸渗仪(Lysimeter)可测量总蒸散量、渗漏量等有关水量平衡的各个分量,具有其它装置和方法不可比拟的优越性。它为田间蒸散和降水入渗实验研究提供了一种较先进的量测方法和技术手段。它对推动我国实验水文学的发展具有重要作用,并为相关领域的科学研究提供了一种较先进的技术设备和实验环境。中国科学院安塞试验站对原建造的用于测定农田蒸腾蒸发转化的称重式蒸渗仪在2005年对称重感应系统、电源进行改造,主要对主机、采集软件进行了重新更新,使其可直接在Windows界面下工作,数据采集更加方便,将测量出来的模拟量信号转换为数字信号,经处理显示并记录在数据采集器内。改进后蒸渗仪主要有以下特点:(1)土柱重19~26t,蒸渗仪精度为152 g(0.05 mm),可测量蒸腾蒸发量和地下水对土壤水的补给量与入渗量;(2)蒸渗仪面积3 m2(1.5 m×2 m),深度3 m,可充分允许农作物根系发育与吸水,土壤水和地下水转化,地下水位变化等过程进行,蒸渗仪的供排水系统能够在蒸渗仪内模拟实际地下水...

瑞丽江流域鱼类组成、区系及生活史特点研究

于2003年9月、2006年4月和11月,分别对瑞丽江流域鱼类资源进行了3次实地调查,共采集到鱼类49种,其中包含1个鱼类属级新纪录及新种——小眼小波鱼(Microrasbora microphthalma)。结合历史资料及文献整理,瑞丽江共有鱼类60种,隶属8目、19科、44属;其中,伊洛瓦底江水系特有鱼类16种,外来引入种9种。鱼类组成上,以鲤科鱼类最多,有26种,占总种数的43.3%;其次为鮡科,有11种,占总种数的18.3%。瑞丽江鱼类区系以喜温的"第三纪类群"中的山区鱼类为主要成分,上游杂有耐高寒的"青藏高原类群"成分,下游杂有热带江河平原鱼类。从生境、生活水层及食性探讨了瑞丽江鱼类生活史特点,并简要分析了鱼类的受危因素并提出了相应的保护建议。

Study on Water Resources Regulation and Reservoir Operating Prediction for Suppression of Salt Water Intrusion in the Pearl River Estuary

Salt water intrusion occurred frequently during dry season in Modaomen waterway of the Pearl River Estuary. With the development of region's economy and urbanization, the salt tides affect the region's water supply more and more seriously in recent years. Regulation and allocation of freshwater resources of the upper rivers of the estuary to suppress the salt tides is becoming important measures for ensuring the water supply security of the region in dry season. The observation data analysis showed that the flow value at the Wuzhou hydrometric station on the upper Xijiang river had a good correlation with the salinity in Modaomen estuary. Thus the flow rate of Wuzhou has been used as a control variable for suppression of salt tides in Modaomen estuary. However, the runoff at Wuzhou mainly comes from the discharge of Longtan reservoir on the upper reaches of Xijiang river and the runoff in the interval open valley between Longtan and Wuzhou sections. As the long distance and many tributaries as well as the large non-controlled watershed between this two sections, the reservoir water scheduling has a need for reasonable considering of interaction between the reservoir regulating discharge and the runoff process of the interval open watershed while the deployment of suppression flow at Wuzhou requires longer lasting time and high precision for the salt tide cycles. For this purpose, this study established a runoff model for Longtan - Wuzhou interval drainage area and by model calculations and observation data analysis, helped to understand the response patterns of the flow rate at Wuzhou to the water discharge of Longtan under the interval water basin runoff participating conditions. On this basis, further discussions were taken on prediction methods of Longtan reservoir discharge scheduling scheme for saline intrusion suppression and provided scientific and typical implementation programs for effective suppression flow process at the Wuzhou section.

核素131I胆道腔内辐照支架的制作和动物实验及临床应用研究

恶性梗阻性黄疸(malignant obstructive jaundice,MOJ)发现时多为晚期,如不治疗生存期仅3个月。由于肿瘤位置特殊、患者一般情况较差,仅5%～20%的患者可行外科切除和分流手术,并且手术死亡率相当高,分流术病死率高达10%～43%。1974年Molnar和Stocknm首先采用PTCD术（经皮肝胆管内外引流术，Percutaneous Transhepatic Cholangic Drainage,PTCD）,使MOJ患者的临床症状得到缓解, 获得进一步治疗的机会。1989年金属支架开始应用于胆道系统,恢复了胆汁的生理性引流,并使大多数患者拔除引流管,提高了生活质量,成为非手术治疗MOJ的首选方法。但肿瘤生长是造成支架堵塞、黄疸复发的主要原因。文献报道MOJ患者放置金属支架后,支架堵塞的概率达20%～86%,其中大多数由肿瘤生长通过支架网眼或超过支架边缘引起。因此,在支架置放的同时如何积极控制肿瘤生长成为提高疗效的关键问题。MOJ的局部治疗方法有多种,但都存在不足之处。国内学者采用动脉化疗栓塞结合PTCD或支架置放的方法治疗MOJ,使患者的生存期得到延长。但引起MOJ的胆管癌、淋巴结转移癌、胰腺癌、壶腹癌多为少血供肿瘤,而且由于血供特殊,大部分病例碘油沉积欠佳,因此动脉化疗栓塞对这类肿瘤的作用是有限的。外辐照治疗对胆管癌、淋巴结转移癌、胰腺癌、壶腹癌等引起MOJ的肿瘤有一定疗效,并与胆道引流术结合应用于上述肿瘤引起的MOJ。由于瘤体周围有肝脏、胰腺、胃肠道、肾脏等对射线敏感的器官, 限制了外辐照剂量,影响了疗效的提高。近几年,一种斩新的治疗手段正在应用于临床，就是通过PTCD手术时建立的通道再行腔内辐照治疗(核素内辐照治疗),可以较好的控制肿瘤继续生长，抑制支架再狭窄的发生,可使MOJ的治疗取得更好的效果。本研究的目的就是探索胆道内辐照支架制作的可行性，并设计特别的施源器，其具体方法可以简述为：以球囊扩张器扩张重度狭窄胆管+置入特制的二腔单囊管+腔内低剂量率放疗+腔内热频热疗+胆管引流等联合方法治疗。同时，就该二腔单囊管内辐照支架的安全性进行动物实验，从分子生物学、核医学的角度阐述了实验研究的机理和病理改变，同时进行了临床的应用研究，探讨胆道支架发生再阻塞的相关因素及对策，进一步提高（MOJ）患者的生存期。本工作结果总结如下： 1 对放射源和施源器均进行了改进，放射源为液态放射性核素131I，施源器为可调节的长柱形球囊，是专门设计的硅橡胶二腔单囊管，其功能为：中腔通接胆管腔（蓝色），具有引流胆汁作用；另一腔管连接球囊（绿色），是长柱状形可调节长短的球囊，囊内装填放射性液态核素131I；囊内还设置射频加热电极，能加热升温。另外，还可以根据肿瘤的大小和长度，来调节施源器的长度（长柱形球囊），一般照射长度超出支架两端1-2cm。二腔单囊管内辐照支架的特点：剂量分布合理，低剂量率效应，射线能量适中，放疗、热疗同步实施，引流、扩张和局部用药作用。与其他治疗方法比较，这一核医学治疗技术的最大优点是：大直径柱状液态源，近似面源，液囊适形病变胆管腔，均匀贴紧病灶壁，剂量分布合理，γ射线能量适中，低剂量率持续照射，同时联合射频温热治疗及胆道引流、局部用药对症处理等。 2 动物实验研究结果指出，囊装液态131I支架对胆管壁的放射性损伤随131I放射性活度的增加而逐渐加重,呈现明显的放射性活度效应关系。而普通支架组胆管壁无放射性损伤,但是胆管壁粘膜层和肌层增生较131I支架组重,胆管出现再狭窄倾向。本研究为临床合理应用131I支架治疗胆管癌及胆管良性狭窄选择合适的131I放射性活度,提供了必要的剂量学和基础研究依据。 3 动物实验研究结果表明,131I支架组犬胆管组织Fas表达较普通支架组明显,且其表达水平的变化与犬胆管壁平滑肌细胞凋亡的检测结果相同。131I支架组胆管腔面积比普通支架组明显增加,胆管狭窄程度比普通支架组轻。这主要是由于131I辐射促进Fas 基因表达,诱导增殖性平滑肌细胞凋亡,从而减轻胆管损伤后愈合过程中的管腔狭窄。 4． 胆道恶性梗阻胆道腔内囊装液态131I辐照治疗施源的直径为8mm时是胆管充分扩张的最低限度,根据近距离放疗的剂量学特点,它能保证胆管癌腔内辐照治疗时将施源管因素导致的放疗反应和局部肿瘤复发减至最低。并具有创伤小,操作简单,疗效明显,易被患者接受的特点。 5．囊装液态131I治疗恶性梗阻性黄疸（肝门部胆管癌18例），临床疗效满意，随访7～21个月,3个月生存率83.33 %(15/ 18)；6个月生存率72.22%(13/18)；9个月生存率56.25%(12/16)；12个月生存率46.15%(6/13),15个月生存率36.33%(4/11)；18个月生存率22.22%(2/9),21个月生存率28.57%(2/7)。4例发生并发症,其中2例为放射性胆管炎胆道出血,1例为胆汁性腹膜炎,另1例是胰瘘胰腺炎

应用输沙量推演流域侵蚀量的方法探讨

鉴于至今还没有一个有效获取流域侵蚀产沙量的方法,在分析悬移质泥沙与侵蚀泥沙之间的数量与粒配关系的基础上,阐述了应用输沙量推演流域侵蚀量在理论上的可能性,但却存在着难点,且主要表现在水文站数量不足与区域分布不均、流域内的生态环境复杂与区域差异大、水文站输沙量观测记录起始时间不同步、及新技术应用存在时空条件的局限性。结合与侵蚀产沙和泥沙输移比相关的定性与定量指标,提出了应用输沙量推演流域侵蚀量的方法,即"层次类剔法",来计算与评估流域侵蚀量和泥沙输移比,具体的操作过程是首先制作一幅流域地貌类型地块图,然后是逐类型、逐类型地块的侵蚀量计算和沟道流域泥沙输移比的判断,最终获取流域不同地块的侵蚀强度和流域泥沙输移比。本研究结果可为水土流失监测点的选择提供科学依据,同时对解决流域的泥沙问题也有重要的启迪作用。

黄土高原分形沟网研究

推测认为黄土高源沟网具有分形性。根据Hoton定律推导沟网分维计算式 ,确定沟网分形结构 ,分形理论求算得小流域沟网的分维D =1.9接近于平面空间时的D =2理论值。统计分析发现流域边界周长、长轴、短轴、长短轴比、汇合角等地貌指标随流域面积的变化。从而证明黄土高源流域的自相似性

基于CorelDRAW软件的小流域模型雨滴测量试验研究

降雨雨谱的观测,是了解降雨特性的一项重要工作。修建小流域模型,是对小流域进行各种试验研究的有效手段。该文基于相似率要求,在模型降雨雨滴较小,雨谱参数难以测定问题的基础上,运用CorelDRAW软件与传统色斑法相结合,探索出一种新的测量与数据处理方法,并得出不同情况下模型的雨谱特性。该法提高了测量精度,并减少了工作量。

Biodegradation of poly(L-lactide-co-glycolide) tube stents in bile

The objective of this study was to evaluate degradation behavior and the feasibility of biodegradable polymeric stents in common bile duct (CBD) repair and reconstruction. Various molar ratios of lactide (LA) and glycolide (GA) in poly(L-lactide-co-glycolide) (PLGA) were synthesized and processed into a circular tubing of similar to 10.0 mm outer diameter and a wall thickness of about 2.0 mm.

Feasibility of biodegradable PLGA common bile duct stents: An in vitro and in vivo study

The current study investigates the feasibility of using a biodegradable polymeric stent in common bile duct (CBD) repair and reconstruction. Here, poly(l-lactide-co-glycolide) (PLGA, molar ratio LA/GA = 80/20) was processed into a circular tube- and dumbbell-shaped specimens to determine the in vitro degradation behavior in bile. The morphology, weight loss, and molecular weight changes were then investigated in conjunction with evaluations of the mechanical properties of the specimen. Circular tube-shaped PLGA stents with X-ray opacity were subsequently used in common bile duct exploration (CBDE) and primary suturing in canine models. Next, X-ray images of CBD stents in vivo were compared and levels of serum liver enzymes and a histological analysis were conducted after stent transplantation. The results showed that the PLGA stents exhibited the required biomedical properties and spontaneously disappeared from CBDs in 4-5 weeks. The degradation period and function match the requirements in repair and reconstruction of CBDs to support the duct, guide bile drainage, and reduce T-tube-related complications.

Rare earth elements in bottom sediments of major rivers around the Yellow Sea: implications for sediment provenance

Rare earth elements (REEs) of 91 fine-grained bottom sediment samples from five major rivers in Korea (the Han, Keum, and Yeongsan) and China (the Changjiang and Huanghe) were studied to investigate their potential as source indicator for Yellow Sea shelf sediments, this being the first synthetic report on REE trends for bottom sediments of these rivers. The results show distinct differences in REE contents and their upper continental crust (UCC)-normalized patterns: compared to heavy rare earth elements (HREEs), light rare earth elements (LREEs) are highly enriched in Korean river sediments, in contrast to Chinese river sediments that have a characteristic positive Eu anomaly. This phenomenon is observed also in primary source rocks within the river catchments. This suggests that source rock composition is the primary control on the REE signatures of these river sediments, due largely to variations in the levels of chlorite and monazite, which are more abundant in Korean bottom river sediments. Systematic variations in I LREE pound/I HREE pound ratios, and in (La/Yb)-(Gd/Yb)(UCC) but also (La/Lu)-(La/Y)(UCC) and (La/Y)-(Gd/Lu)(UCC) relations have the greatest discriminatory power. These findings are consistent with, but considerably expand on the limited datasets available to date for suspended sediments. Evidently, the REE fingerprints of these river sediments can serve as a useful diagnostic tool for tracing the provenance of sediments in the Yellow Sea, and for reconstructing their dispersal patterns and the circulation system of the modern shelf, as well as the paleoenvironmental record of this and adjoining marginal seas.

Evolution and variability of the East Asian summer monsoon during the Pliocene: Evidence from clay mineral records of the South China Sea

The Late Pliocene is thought to be characterized by the simultaneous intensification of both the East Asian winter monsoon (EAWM) and East Asian summer monsoon (EASM). However, the evolution of the EASM during the Pliocene remains still controversial and only little is known about the dynamics of the EASM during the Pliocene on orbital time scales. Here we use clay mineral assemblages in sediments from Ocean Drilling Program (ODP) Site 1143 in the southern South China Sea (SCS) to obtain proxy records of past changes in the EASM climate during the Pliocene. Provenance analysis suggests that illite, chlorite and kaolinite originated mainly from the Mekong River drainage area. Smectite was derived mainly from the Indonesian islands. The kaolinite/illite ratio and the chemical index of alteration (CIA) of siliciclastic sediments allowed us to reconstruct the history of chemical weathering and physical erosion of the Mekong River drainage area and thus, the evolution of,the EASM during the Pliocene. Our clay minerals proxy data suggests a stronger EASM during the Early Pliocene than during the Late Pliocene. We propose that the long-term evolution of the EASM has been driven by global cooling rather than the uplift of the Tibetan Plateau. Spectral analysis of kaolinite/ illite ratio displays a set of strong periodicities at 100 ka, 30 ka, 28 ka, 25 ka, and 22 ka. with no clear obliquityrelated signal. Our study suggests that the Pliocene EASM intensity on orbital time scales is not only controlled by the Northern Hemisphere summer insolation, but also strongly influenced by equatorial Pacific ENSO-like ocean atmosphere dynamics. (C) 2010 Elsevier B.V. All rights reserved.

末次冰盛期以来黑潮流域的古环境演化

2005年6月，中法国际合作在西太平洋海域执行IMAGES XII-MD147 Micro Polo1航次科学考察时，由法国极地研究所R/V Marine Dufresne极地考察船利用Calypso重力取样器于冲绳海槽南部钻取了34.2米长MD05-2908柱状样。本文利用AMS14C测年数据建立了该孔的年代模型，对该孔的浮游有孔虫动物群落进行了分析，并利用FP-12E浮游有孔虫转换函数和Q型因子分析方法对该孔浮游有孔虫数据进行了研究，对全新世以来的黑潮流系演化和古环境记录进行了讨论。 结果表明，中晚全新世存在着5次洪水爆发期，洪水爆发期与当时温暖气候相对应，而高海平面对洪水的爆发也产生了影响。进入全新世以来的6790～4000a B.P.期间，黑潮流一直有稳步增强的趋势，黑潮流始终位于冲绳海槽内；4000～3000a B.P.期间，黑潮强度减弱或者发生明显东偏，冲淡水影响增强；3000a B.P.以后黑潮强度逐渐增强，1650～0a B.P.为中晚全新世以来黑潮活动最强的时期,在600a B.P.和140a B.P.左右存在低值，黑潮强度短暂减弱。普林虫低值事件在MD05-2908孔中有很好的体现，对该事件进行了进一步定年，其发生时间为3900～2800a B.P.，持续时间为1100a，该事件的发生可能与东亚冬季风加强有关。 冲绳海槽中晚全新世气候变化可以分为四个阶段： 6790～4800a B.P.低温阶段，4800～4100a B.P.高温阶段，4100～2400a B.P.低温阶段，2400～0a B.P.波动高温阶段。通过与中国及世界其它地方对比可以识别出6.3～5.9、5.5、4.6～4.2、3.6～3.0、2.9～2.4、1.3～1.0、0.5～0.1ka B.P.六个降温事件，为全新世气候波动在深海高分辨率沉积记录中的响应提供了有力支持。该孔SST频谱分析结果显示，存在着3008a、1061a这种千年尺度的周期，以及215a、123a、103～107a、81～78a以及73～71a等周期，表明该孔SST变化与太阳活动强度是密切相关的。 中晚全新世以来，黑潮流在冲绳海槽逐步加强，到4000aB.P.左右达到最大，然后4000～3000a B.P.期间，黑潮强度明显减弱或者发生东偏，3000aB.P.以后，黑潮强度持续增强，在近1000aB.P.波动较大。 对冲绳海槽地区14个柱状样氧同位素以及P.obliquiloculata丰度进行研究，发现LGM以来，黑潮流可能仍然在冲绳海槽地区活动，并没有移出海槽外，但是由于其强度减弱，其流径发生了很大变化。

Genetic diversity and historical population structure of Schizopygopsis pylzovi (Teleostei : Cyprinidae) in the Qinghai-Tibetan Plateau

1. Complete sequences of 1140 base pair of the cytochrome b gene from 133 specimens were obtained from nine localities including the inflow drainage system, isolated lakes and outflow drainage system in Qinghai-Tibetan Plateau to assess genetic diversity and to infer population histories of the freshwater fish Schizopygopsis pylzovi.2. Nucleotide diversities (pi) were moderate (0.0024-0.0045) in populations from the outflow drainage system and Tuosuo Lake, but low (0.0018-0.0021) in populations from Qiadam Basin. It is probable that the low intra-population variability is related with the paleoenvironmental fluctuation in Qiadam Basin, suggesting that the populations from Qiadam Basin have experienced severe bottleneck events in history.3. Phylogenetic tree topologies indicate that the individuals from different populations did not form reciprocal monophyly, but the populations from the adjacent drainages cluster geographically. Most population pairwise F-ST tests were significant, with non-significant pairwise tests between Tuosu Lake and Tuosuo Lake in the north-west of the Qinghai-Tibetan Plateau. Analysis of molecular variance (AMOVA) indicates that the significant genetic variation was explained at the levels of catchments within and among, not among specific boundaries or inflow and outflow drainage systems.4. The nested clade phylogeographical analysis indicates that historical processes are very important in the observed geographical structuring of S. pylzovi, and the contemporary population structure and differentiation of S. pylzovi may be consistent with the historical tectonic events occurred in the course of uplifts of the Qinghai-Tibetan Plateau. Fluctuations of the ecogeographical environment and major hydrographic formation might have promoted contiguous range expansion of freshwater fish populations, whereas the geological barriers among drainages have resulted in the fragmentation of population and restricted the gene flow among populations.5. The significantly large negative F-s-value (-24.91, P < 0.01) of Fu's F-s-test and the unimodal mismatch distribution indicate that the species S. pylzovi underwent a sudden population expansion after the historical tectonic event of the Gonghe Movement.6. The results of this study indicate that each population from the Qinghai-Tibetan Plateau should be managed and conserved separately and that efforts should be directed towards preserving the genetic integrity of each group.

植物对环境污染的磁学响应机理研究

With development of industry and acceleration of urbanization, problems of air quality as well as their influences on human health have recently been regarded highly by current international communities and governments. Generally, industrializations can result in exhausting of a lot of industry gases and dusts, while urbanization can cause increasing of modern vehicles. Comparing with traditional chemical methods, magnetic method is simple, rapid, exact, low-cost and non-destructive for monitoring air pollution and has been widely applied in domestic and international studies. In this thesis, with an aim of better monitoring air pollution, we selected plants (highroad-side perennial pine trees (Pinus pumila Regel) along a highroad linking Beijing City and the Capital International Airport, and tree bark and tree ring core samples (willow, Salix matsudana) nearby a smelting industry in northeast Beijing) for magnetic studies. With systemic magnetic measurements on these samples, magnetic response mechanism of contamination（e.g. tree leaves, tree ring）to both short- and long-term environmental pollution has been constructed, and accordingly the pollution range, degree and process of different time-scale human activities could be assessed. A series of rock magnetic experiments of tree leaves show that the primary magnetic mineral of leaf samples was identified to be magnetite, in pseudo-single domain (PSD) grain size range of 0.2-5.0 μm. Magnetite concentration and grain size in leaves are ascertained to decrease with increasing of sampling distance to highroad asphalt surface, suggesting that high magnetic response to traffic pollution is localized within a distance of about 2 m away from highroad asphalt surface. On the other hand, highroad-side trees and rainwater can effectively reduce the concentration of traffic pollution-induced particulate matters (PMs) in the atmosphere. This study is the first time to investigate the relationship of smelting factory activities and vicissitudes of environment with tree rings by magnetic methods. Results indicate that magnetic particles are omnipresent in tree bark and trunk wood. Magnetic techniques including low-temperature experiment, successive acquisition of IRM, hysteresis loops and SIRM measurements suggest that magnetic particles are predominated by magnetite in pseudo-single domain state. Comparison of magnetic properties of tree trunk and branch cores collected from different directions and heights implies that collection of magnetic particles depends on both sampling direction and height. Pollution source-facing tree trunk wood contains significantly more magnetic particles than other sides. These indicate that magnetic particles are most likely intercepted and collected by tree bark first, then enter into tree xylem tissues by translocation during growing season, and are finally enclosed in a tree ring by lignifying. Correlation between magnetic properties such as time-dependent SIRM values of tree ring cores and the annual steel yields of the smelting factory is significant. Considering the dependence of magnetic properties in sampling directions, heights, and ring cores, we proposed that magnetic particles in the xylem cannot move between tree rings. Accordingly, the SIRM and some other magnetic parameters of tree ring cores from the source-facing side could be contributed to historical study of atmospheric pollution produced by heavy metal smelting activities, isoline diagrams of SIRM values of all the tree rings indicate that air pollution is increasing worse. We believed that a synthetic rock magnetic study is an effective method for determining concentration and grain size of ferromagnets in the atmospheric PMs, and then it should be a rapid and feasible technique for monitoring atmospheric pollution.