一种新型的置换海底子母管道技术

在BZ34—3／5边际油田海洋工程开发过程中，考虑到渤海海域的环境气候与所产原油的凝点，混输管道在冬季停输的情况下，管内原油容易在较短时间内凝固而堵塞海底管道，因此设计中须考虑管道的应急置换措施。为规避风险及符合边际油田开发投资成本小的宗旨，设计者引入了一种新型的管道结构形式-子母管道（Bundled Pipeline）。在停输的情况下，利用周边油田的已有设施，将子管内柴油反向输送至混输管道（母管）入口，将管内原油置换出来。介绍了子母管道在设计、安装过程中与传统海底管道的不同之处。混输、置换（子管）管道通过绑扎于一体进行安装铺设，这样在很大程度上节省了海上工程的费用与时间，目前该油田已投产且运转正常。

海底(子母)管道在波流作用下水动力载荷的实验研究

本文是在研究组对“波流作用下海底管道水动力系数 C_D、C_M、C_L 值的确定和选取”、“带压块海底管道上的水动力载荷实验研究”和“部分埋设海底管道渡流作用时的水动力效应实验研究”等项目研究成果的基础上,以 JZ20-2海底输气管道工程的为背景,对 JZ20-2的子-母管在波流作用下水动力载荷的确定进行的实验研究。同样,子-母管的水动力系数 C_D、C_M 与 KC 数明显相关,随KC 数的增大而减小;水动力系数 C_M 多在1—4之间变化。实验中对规则波加拖厢造流与不规则波自然加流的试验结果,二者比较—致。因而建议在工程设计中,可直接按规则波加拖厢造流的方法和设备,并偏于保守。

细松管层绞式光缆和气送技术的进展

综述了细松管层绞式光缆在利用气送技术进行安装,在节约光缆与管道成本和减少对环境污染等方面的优越性。阐述了为了在减小管径的情况下能够保持适当的抗拉性能和高低温性能,必须仔细选用松管材料和改进挤出工艺以获得适当的光纤余长。介绍了芬兰NK光缆公司在细松管用材料的选择和工艺改进方面所取得的成果介绍了英国电信与Pirelli光缆厂等合作进行的细松管层绞式光缆的试制和现场试验情况。

Structure design for electron beam controlling in microwave tube with carbon nanotube cathode

To control the electron beam emitted from the carbon nanotube （CNT） cathode, four different electron chunnels are designed. A common basic structure used in the simulation is an insulating chunnel. When primary electrons hit the surface of the chunnel, secondary electrons are generated, which make the electron distribution at the exit hole of the chunnel more uniform. By analyzing and comparing the state of electrons emitted from the exit of chunnel among the four structures, an optimal structure is obtained. In the optimized structure, the electron distribution at the exit hole of the chunnel is more uniform and the electron beam is rather slim. Furthermore, by adding a magnetic field along the slow wave line, the electron beam can be constrained. In the optimized structure, a very small magnetic field is needed to make most of electrons pass through the slow wave line.

Histological and immunocytochemical study of deferens ducts in the Chinese rat snake (Zaocys dhumnades)

To investigate the relationship between structure and function of the deferens ducts in the Chinese rat snake （Zaocys dhumnades）, morphological changes within an annual cycle were observed by routine histological techniques. Also, the correlation of androgen receptor （AR）, estrogen receptor （ER）, progesterone receptor （PR） and aromatase （Ar） expressions in the vas deferens and testis were studied immunohistochemically. To confh＇m that the sperm and the spherical structure existed in deferens ducts, we also used routine histological technique observed deferens ducts in the Striped-tailed rat-snake （Elaphe taeniura）, Red-banded snake （Dinodon rufozonatum）, and Tiger-spotted neck- troughed snake （Rhabdophis tigrina lateralis）. The results showed that the deferens ducts of the Chinese Rat Snake were composed of efferent duct, epididymal duct and vas deferens. Efferent duct contained sperm from August-October, and the sperm were observed in the epididymal duct from August-the following January. Throughout the year （except July） a large number of sperm were present in the vas deferens where a previously unreported spherical structure formed by spermatids was observed, which showed no significant differences in the IOD values of AR-, ER-, PR- and Ar- immunoreactivities. Since the spermatids in the spherical structure were undergoing spermatogenesis and this phenomenon also existed in the Striped-tailed rat-snake and Red-banded snake, the term, seminiferous spherule, was named for this spherical structure This study demonstrated that the testis was the main site for snake spermiogenesis, and the seminiferous spherule in vas deferens was the other Both the epididymis and vas deferens stored sperm; however, the vas deferens was the main organ for sperm storage.

塑料大棚内太阳能贮热系统

一、太阳能贮热系统的原理 塑料大棚内由于温室效应,在早春和晚秋季节,白天棚内的气温往往高于作物所需温度,即有多余的太阳能;而在夜晚,棚内气温往往低于作物所需温度,需要补充热量。太阳能贮热系统,就是利用风机把白天棚内的热空气经管道送入地下。

A New Method for InGaAs/InP Composite Channel HEMTs Simulation

A new method is used to simulate InGaAs/InP composite channel high electron mobility transistors （HEMTs）. By coupling the hydrodynamic model and the density gradient model, the electron density distribution in the channel in different electric fields is obtained. This method is faster and more robust than traditional meth- ods and should be applicable to other types of HEMTs simulations. A detailed study of the InGaAs/InP composite channel HEMTs is presented with the help of simulations.

Endoscopic occlusion with silicone spigots for the closure of refractory esophago-bronchiole fistula after esophagectomy

A 65-year-old man with cT1bN0M0 stage I middle thoracic esophageal cancer underwent subtotal esophagectomy and gastric tube reconstruction through the posterior mediastinal route after preoperative carbon-ion radiotherapy and chemotherapy in a clinical trial. Anastomotic leakage occurred, but it spontaneously improved. At six months after the operation, he was rehospitalized with a cough and dysphagia. An esophago-bronchiole fistula and stenosis of the gastric tube were observed. He first underwent stent placement in the gastric tube. Two weeks later, the syringeal epithelium was burned by argon plasma coagulation after stent removal. Endoscopic occlusion was then performed for the fistula with two guidewire-assisted silicone spigots. Two weeks later, he was discharged on an oral diet, and he has not developed recurrence of the fistula or cancer for three years. This is the first report of endoscopic occlusion with a guidewire-assisted silicone spigot through the esophagus.

Stability and Drag Reduction in Transient Channel Flow of Fibre Suspension

Drag reduction features in the transition regime of channel flow with fibre suspension were analyzed in terms of the linear stability theory. The modified stability equation was obtained based on the slender-body theory and natural closure approximation. Results of the stability analysis show attenuating effects of fibre additives to the flow instability. For the cases leading to transition, drag reduction rate increases with the characteristic parameter H of fibres. The mechanism of drag reduction by fibres is revealed through the variation of velocity profile and the decrease of wall shear stress. The theoretical results are qualitatively consistent with some typical experiments.

Direct cholangioscopy combined with doubleballoon enteroscope-assisted endoscopic retrograde cholangiopancreatography

Double-balloon enteroscope (DBE)-assisted endoscopic retrograde cholangiopancreatography (ERCP) is an effective endoscopic approach for pancreatobiliary disorders in patients with altered gastrointestinal anatomy. Endoscopic interventions via DBE in these postoperative settings remain difficult because of the lack of an elevator and the use of extra-long ERCP accessories. Here, we report the usefulness of direct cholangioscopy with an ultra-slim gastroscope during DBE-assisted ERCP. Three patients with choledocholithiasis in postoperative settings (two patients after Billroth Ⅱ gastrojejunostomy and one patient after Roux-en-Y gastrojejunostomy) were treated. DBE was used to gain access to the papilla under carbon dioxide insufflation, and endoscopic sphincterotomy was performed with a conventional sphincterotome. For direct cholangioscopy, the enteroscope was exchanged for an ultra-slim gastroscope through an incision in the overtube, which was inserted directly into the bile duct. Direct cholangioscopy was used to extract retained bile duct stones in two cases and to confirm the complete clearance of stones in one case. Bile duct stones were eliminated with a 5-Fr basket catheter under direct visual control. No adverse events were noted in any of the three cases. Direct cholangioscopy with an ultra-slim gastroscope facilitates subsequent treatment within the bile duct. This procedure represents another potential option during DBE-assisted ERCP.

Global optimization for ducted coaxial-rotors aircraft based on Kriging model and improved particle swarm optimization algorithm

To improve the operational efficiency of global optimization in engineering, Kriging model was established to simplify the mathematical model for calculations. Ducted coaxial-rotors aircraft was taken as an example and Fluent software was applied to the virtual prototype simulations. Through simulation sample points, the total lift of the ducted coaxial-rotors aircraft was obtained. The Kriging model was then constructed, and the function was fitted. Improved particle swarm optimization(PSO) was also utilized for the global optimization of the Kriging model of the ducted coaxial-rotors aircraft for the determination of optimized global coordinates. Finally, the optimized results were simulated by Fluent. The results show that the Kriging model and the improved PSO algorithm significantly improve the lift performance of ducted coaxial-rotors aircraft and computer operational efficiency.

High-Temperature Corrosion of Protective Coatings for Boiler Tubes in Thermal Power Plants

High-temperature corrosion is a serious problem for the water-wall tubes of boilers used in thermal power plants. Oxidation, sulfidation and molten salt corrosion are main corrosion ways.Thereinto, the most severe corrosion occurs in molten salt corrosion environment. Materials rich in oxides formers, such as chromium and aluminum, are needed to resist corrosion in high-temperature and corrosive environment, but processability of such bulk alloys is very limited. High velocity electric arc spraying (HVAS) technology is adopted to produce coatings with high corrosion resistance. By comparison, NiCr (Ni-45Cr-4Ti) is recommended as a promising alloy coating for the water-wall tubes, which can even resist molten salt corrosion attack. In the study of corrosion mechanism, the modern material analysis methods, such as scanning electron microscopy (SEM), X-ray diffractometry (XRD) and energy dispersive spectrometry (EDS), are used. It is found that the corrosion resistances of NiCr and FeCrAI coatings are much better than that of 20g steel, that the NiCr coatings have the best anti-corrosion properties, and that the NiCr coatings have slightly lower pores than FeCrAI coatings.It is testified that corrosion resistance of coatings is mainly determined by chromium content, and the microstructure of a coating is as important as the chemical composition of the material. In addition, the fracture mechanisms of coatings in the cycle of heating and cooling are put forward. The difference of the thermal physical properties between coatings and base metals results in the thermal stress inside the coatings. Consequently, the coatings spall from the base metal.

Overlap of reflux and eosinophilic esophagitis in two patients requiring different therapies:A review of the literature

Eosinophilic esophagitis (EE) and gastroesophageal reflux disease (GERD) have overlapping clinical, manometric, endoscopic and histopathologic features. The diagnosis of EE is nowadays based upon the presence of 15 or more eosinophils per high power field (eo/HPF) in esophageal biopsies. We report the cases of two young males suffering from dysphagia and recurrent food impaction with reflux esophagitis and more than 20 eo/HPF in upper-mid esophagus biopsies, both of which became asymptomatic on proton pump inhibitor (PPI) therapy. The first patient also achieved a histologic response, while EE remained in the other patient after effective PPI treatment, as shown by 24-h esophageal pH monitoring. Topical steroid therapy combined with PPI led to complete remission in this latter patient. GERD and EE may be undistinguishable, even by histology, so diagnosis of EE should only be established after a careful correlation of clinical, endoscopic and pathologic data obtained under vigorous acid suppression. These diagnostic difficulties are maximal when both diseases overlap. Limited data are available about this topic, and the interaction between EE and GERD is a matter of debate. In this setting, upper-mid esophagus step biopsies and esophageal pH monitoring of patients on PPI therapy are pivotal to evaluate the role of each disease. A PPI trial is mandatory in patients with a histopathologic diagnosis of EE; in those unresponsive to PPI treatment, EE should be suggested. However, a clinical response to PPI may not rule out quiescent EE, as shown in this report.

Heterogeneity of endoscopy negative heartburn:Epidemiology and natural history

It has now become clear that only about 40% or less of patients with heartburn and/or regurgitation have esophagitis, and that the majority of them lack visible distal esophageal mucosa breaks. These subjects are referred to as non-erosive gastroesophageal reflux disease (NERD) patients. It has been estimated that in the Western world at least one tenth of the general population has at least weekly heartburn. This proportion seems to be lower in Asia, while prevalence is rapidly increasing. Although it would be extremely useful to have prospective information regarding the fate of such patients, the natural history of NERD is largely unknown, and very few studies in the literature have addressed this issue. These studies are for the greater part old, not well conducted, and suffer from methodological drawbacks including ill-defined entry criteria. However, a review of these studies indicates that a consistent minority of NERD patients may develop erosive disease at an approximate rate of about 10% per year.

Quantum Secret Sharing Based on Chinese Remainder Theorem

A novel quantum secret sharing （QSS） scheme is proposed on the basis of Chinese Remainder Theorem （CRT）. In the scheme, the classical messages are mapped to secret sequences according to CRT equations, and distributed to different receivers by different dimensional superdense-coding respectively. CRT＇s secret sharing function, together with high-dimensional superdense-eoding, provide convenience, security, and large capability quantum channel for secret distribution and recovering. Analysis shows the security of the scheme.

Effects of warm ischemia time on biliary injury in rat liver transplantation

AIM:To investigate the effect of different secondary warm ischemia time (SWIT) on bile duct injury in livertransplanted rats. METHODS:Forty-eight male inbred Sprague-Dawley rats were randomly assigned into four groups:a shamoperation group and three groups with secondary biliary warm ischemia time of 0 min, 10 min and 20 min. A rat model of autologous liver transplantation under ether anesthesia was established, and six rats were killed in each group and blood samples and the median lobe of the liver were collected for assay at 6 h and 24 h after hepatic arterial reperfusion. RESULTS:With prolongation of biliary warm ischemia time, the level of vascular endothelial growth factor-A was significantly decreased, and the value at 24 h was higher than that at 6 h after hepatic arterial reperfusion, but with no significant difference. The extended biliary SWIT led to a significant increase in bile duct epithelial cell apoptosis, and a decrease in the number of blood vessels, the bile duct surrounding the blood vessels and bile duct epithelial cell proliferation in the early postoperative portal area. Pathologic examinations showed that inflammation of the rat portal area was aggravated, and biliary epithelial cell injury was significantly worsened. CONCLUSION:A prolonged biliary warm ischemia time results in aggravated injury of the bile duct and the surrounding vascular plexus in rat autologous orthotopic liver transplantation.

A new partial trisomy 12p with artery catheter vagus,congenital cataract,no turbinate and external auditory canal

We describe the prenatal diagnosis and fetal phenotype of partial trisomy 12 （pl2-pter） transmitted from a maternal reciprocal translocation 6;12. Genetic analysis of umbilical cord blood of a 27-year-old woman, gravida 4, para 1 at 35 weeks＇ gestation due to a tricuspid regurgitation and orbital hypertelorism by sonography revealed an unusual karyotype of 46, XY, der （6） t （6;12） （p24;p12） mat. The pregnancy was terminated at 37 gestational weeks. The proband postnatally displayed by dysmorphic features of a round flat face with prominent cheeks and high forehead, hypertelorism, a short nose, a broad and depressed nasal bridge, anteverted nares, a deformed philtrum, an open mouth, thin upper vermilion and broad everted lower lip, low-set ears and aural atresia, broad hands with simian creases, and a short neck. By anatomy, the fetal was found to have right artery catheter vagus, congenital cataract, no turbinate and external auditory canal. Through the karoytpye-phynotpye analysis on the present patient and a review of other reported cases, we believed that the case was the first report, which expanded the database of partial trisomy 12p, and was of benefit for future clinical genetic counseling. At the same time, this study supported the viewpoint that phenotypic variability depends on the type and extent of the associated partial monosomy

Simulating Experiment and Circuit Simulation of RTD/HPT Photo-Controlled MOBILE

The MOBILE is a logic element realizing the monostable-bistable transition of a circuit that consists of two resonant tunneling transistors—the resonant tunneling diodes (RTDs) connected in series. It has several advantages including multiple inputs and multiple functions. In this paper, by connecting a heterojunction phototransistor (HPT) with the MOBILE, a novel optoelectronic functional device can be got, which presents the function of both photocurrent switching and photocurrent latching. These behaviors have been demonstrated for the first time by simulating experiments and circuit simulations, with RTDs firstly manufactured in China. Research indicates that the novel photo-controlled MOBILE has the same logic functions as conventional electrical MOBILE except for with light as an input signal.

Changes of Ca^2+ activated potassium channels and cellular proliferation in autogenous vein grafts

Objective: To investigate changes of Ca2+ activated potassium channels (KCa) in autogenous vein grafts. Methods: Contraction of venous ring was measured by means of perfusion in vitro. The intimal rabbits proliferation of vascular and proliferation of cultured smooth muscle cells(vascular smooth muscle cells, VSMCs)were observed by the means of computerised image analysis and MTT method respectively. Furthermore, whole cell mode of patch clamp was used to record KCa of VSMCs isolated from autogenous vein grafts. Results: One week after transplantation there were no significant differences of contraction and intimal relative thickness between autogenous vein grafts and control. Contraction and intimal relative thickness of autogenous vein graft were significantly increased 2 weeks after transplantation (P<0.05, n=8 vs control), and they was more enhanced 4 weeks after vein transplantation (P<0.01, n=8 vs control).TEA(blocker of Ca2+ activated potassium channels)increased MTT A490 nm value of VSMCs from femoral vein in a dose dependent manner(P<0.05, n=8). KCa current density was significantly attenuated in VSMCs from autogenous vein grafts (1-4) week after transplantation(P<0.05, n=5).Conclusion: KCa is inhibited in autogenous vein graft, which account for vasospasm and intimal proliferation.

Influence of Nonionic Surfactant Addition on Drag Reduction of Water Based Nanofluid in a Small Diameter Pipe

The goal of this research was to determine the impact of nonionic surfactants on drag reduction effect in water and metal oxide nanofluid. Two nonionic surfactants （Rokacet 07 and Rokanol KT） and copper（II） oxide wa- ter-based nanofluid were examined. Friction factors in a 4 mm diameter pipe for the Reynolds number between 8000 and 50000 were determined. Results showed that addition of nonionic surfactants caused the decrease of fric- tion factor in water and nanofluid. The drag reduction effect was similar in both cases. Presence of nanoparticles in the system has no great influence on drag reduction effect.