双曲映射的Lorentz保形性

本文证明了双曲函数是双曲映射(即连续可微)的充要条件:它是Lorentz保形的。

基于图像处理的织物保形性检测

为更加全面、准确地评价织物保形性,开发了能够模拟织物在日常使用中被压皱后展平的恢复过程动态检测系统。通过检测系统获取织物折痕回复的视频序列,利用程序提取出各时刻的单帧视频图像,然后依次对图像进行预处理、二值化处理与细化处理,最后提取出反映织物保形性的指标,包括顶角、顶高、保形面积。实验结果表明:在折痕回复阶段,随时间延长各指标变化速率逐渐降低,在压力为10 N,加压时间为10 s的条件下,试样在60 s后趋于平稳;60 s时的顶角与现有标准方法测得的折皱回复角存在线性函数关系,顶高、保形面积与标准方法测得的悬垂系数之间存在线性函数关系。该系统可以通过顶角、顶高、保形面积3项指标预测织物折皱回复角与悬垂系数,并能够精确描述织物保形性动态变化过程,可实现对织物保形性精确、全面的评价。

织物保形性检测系统开发初探

探讨综合评价织物保形性的方法。开发了一种模拟织物被压皱后自动展开的保形性检测系统。通过新型检测装置与视频图像处理技术的结合,从处于折痕恢复过程中的织物上提取出反映保形性的指标,选取纯棉织物进行测试,分析提取所得指标与现有标准方法测得织物折皱回复性、悬垂性之间的关系。试验结果表明:该检测系统用于织物保形性检测中数据准确可靠。认为:该织物保形性检测系统可实现对纯棉织物保形性相关指标的快速精准评价。

K-对称变换及其K保圆(周)性

在K-复数,K-导数,K-解析(函数)变换的K-保角,K-共形映射以及边界对应定理等的基础上,研究了K-对称变换及其K保圆性.所得结论是解析函数与共轭解析函数的几何理论在K-解析函数中的继续和应用.

自组织特征映射网络在遥感影像分类中的应用

该研究以Matlab为平台,应用自组织特征映射网络模型对研究区的遥感影像数据进行土地使用类型的分类。结果表明:在设计神经网络模型时,输出层节点数的确定不仅与分类数相关,同时也需要考虑研究区数据的模数,输出层节点数正确与否很大程度上制约着研究结果的精度。研究证明,自组织特征映射网络通过神经元之间的竞争能模拟大脑神经系统中的"近兴奋远抑制"功能使得该网络的收敛性更好,其分类精度较高,而且该神经网络不需要学习样本使其应用更加简单。因此自组织特征映射网络在遥感分类中有着很好的应用前景。

基于多目标遗传算法的星载天线干扰抑制算法

提出了一种基于多目标遗传算法的星载天线干扰抑制算法,该算法在射频端通过调节权系数进行输出功率判决从而实现波束形成。文中引入多目标优化问题Pareto最优解的概念,采用了无支配性排序遗传算法(NSGA-Ⅱ)来搜索干扰调零权值的Pareto最优解集,充分发挥这种先进多目标遗传算法的高内在并行性、强鲁棒性以及能够不断优化最优解集的优势,较好地兼顾了星载天线干扰抑制时干扰抑制深度与主波束保形这一对矛盾问题。最后提出了归一化双目标函数加权选择最优调零权的方法从Pareto最优解集中选择一组符合决策者偏好的最优调零权。计算机仿真实验证明,文中所提出的算法具有较好的干扰抑制能力和主波束保形效果。

一种改进的MQ拟插值算子

基于Multiquadric(MQ)拟插值算子,构造出一种新的拟插值算子Ld,证明了该算子具有二次多项式再生性以及严格三次保形性。最后通过数值算例验证了该算子具有良好的逼近精度,尤其是对幂函数和指数型函数都有很好的逼近效果。

Effect of lead on ERK activity and the protective function of bFGF in rat primary culture astroglia

Objective： To observe the effects of lead on levels ofphosphorylated extracellular signal regulated kinase （p-ERK） in the cytoplasm of primary cultures of rat astroglial cells and the possible protective effect of basic fibroblast growth factor （bFGF） on lead-induced effects. Methods： The primary astroglia cells from 1-6 d old Wistar rats were cultured. The cells pretreated with the MEK1 （mitogen-activated protein kinase kinase 1） inhibitor PD98059 and bFGF, respectively, were exposed to Pb acetate of different concentrations for different times. Western blotting and reverse transcription polymerase chain reaction （RT-PCR） methods were used to detect the protein and mRNA expressions of ERK. Results： mRNA expression for ERK peaked 15 min after initiation of lead exposure （P〈0.05） and protein expression of p-ERK peaked at 30 min （P〈0.05）. ERK mRNA levels and p-ERK protein levels returned to baseline after 60 and 120 min of lead exposure, respectively （P〉0.05）. The increase in p-ERK levels in lead-treated cells could be inhibited by PD098059. Activation of ERK in the cells by lead was prevented by pretreatment with bFGF. Total ERK protein levels did not change under the same experimental conditions （P〉0.05）. Conclusion： Low-level lead exposure resulted in transient activation of ERK through the MEK pathway, which then returned to basal levels in the continued presence of lead. Exogenous bFGF protected ERK signaling components in astroglia from lead poisoning.

Should anticoagulants be administered for portal vein thrombosis associated with acute pancreatitis?

Venous complications in patients with acute pancreatitis typically occur as a form of splenic,portal,or superior mesenteric vein thrombosis and have been detected more frequently in recent reports.Although a well-organized protocol for the treatment of venous thrombosis has not been established,anticoagulation therapy is commonly recommended.A 73-year-old man was diagnosed with acute progressive portal vein thrombosis associated with acute pancreatitis.After one month of anticoagulation therapy,the patient developed severe hematemesis.With endoscopy and an abdominal computed tomography scan,hemorrhages in the pancreatic pseudocyst,which was ruptured into the duodenal bulb,were confirmed.After conservative treatment,the patient was stabilized.While the rupture of a pseudocyst into the surrounding viscera is a well-known phenomenon,spontaneous rupture into the duodenum is rare.Moreover,no reports of upper gastrointestinal bleeding caused by pseudocyst rupture in patients under anticoagulation therapy for venous thrombosis associated with acute pancreatitis have been published.Herein,we report a unique case of massive upper gastrointestinal bleeding due to pancreatic pseudocyst rupture into the duodenum,which developed during anticoagulation therapy for portal vein thrombosis associated with acute pancreatitis.

What is the optimal treatment for appendiceal mass formed after acute perforated appendicitis?

We read with great interest the editorial article by Meshikhes AWN published in issue 25 of World J Gastroenterol 2011.The article described the advantages of emergency laparoscopic appendectomy compared with interval appendectomy as a new safe treatment modality for the appendiceal mass.The author concluded that the emergency laparoscopic appendectomy was a safe treatment modality for the appendiceal mass,and might prove to be more cost-effective than conservative treatment,with no need for interval appendectomy.However,we would like to highlight certain issues regarding the possibility of percutaneous catheter drainage to successfully treat the appendiceal mass,with no need for appendectomy,too.

Shape retention of injection molded stainless steel compacts

The effects of the binder composition, the powder loading, the thermal properties of feedstocks, and the injection molding parameters on the compact shape retention for metal injection molding 17-4PH stainless steel were investigated. The high-density polyethylene is more effective than ethylene vinyl acetate as a second component of the wax-based binder to retain compact shape due to its higher pyrolytic temperature and less heat of fusion. The compact distortion decreases with increasing the powder loading, molding pressure and molding temperature. There exists an optimal process combination including the powder loading of 68%, molding pressure of 120MPa and molding temperature of 150℃. Under this process condition, the percentage of distorted compacts is the lowest.

Mercury speciation and removal across full-scale wet FGD systems at coal-fired power plants

The Ontario Hydro Method （OHM） recommended by the United States Environmental Protection Agency （EPA） was used to determine mercury speciation in the combustion flue gas across wet FGD systems. Four coal-fired units with wet FGD systems were chosen to evaluate mercury speciation and mercury removal efficiencies through these wet FGD systems. Chlorine content in coal had been suggested as a main factor that affects mercury speciation in flue gas. It is shown that the higher the chlorine concentration in coal is, the higher the percentage of oxidized mercury （Hg2＋） is removed in wet FGD systems, which can increase overall mercury removal efficiencies through wet FGD systems. The selective catalyst reduction （SCR） system has a function of oxidizing ele- mental mercury （Hg0） to oxidized mercury. A higher percentage of oxidized mercury in the total vapor mercury at the FGD inlet is observed when SCR is in service. Therefore, higher overall mercury removal efficiencies through wet FGD are attained. Because of different wet FGD operating conditions, there are different mercury removal efficiencies in different units. Elemental mercury reemission took place when a fraction of oxidized mercury absorbed in the slurry is reduced to elemental mercury, and Hg2＋ is reemitted from stack, which results in decreases in mercury removal efficiencies through wet FGD systems.

A special recurrent pattern in small hepatocellular carcinoma after treatment:Bile duct tumor thrombus formation

AIM:To investigate the clinicopathologic features of bile duct tumor thrombus(BDTT) occurrence after treatment of primary small hepatocellular carcinoma(sHCC) .METHODS:A total of 423 patients with primary sHCC admitted to our hospital underwent surgical resection or local ablation.During follow-up,only six patients were hospitalized due to obstructive jaundice,which occurred 5-76 mo after initial treatment.The clinicopathologic features of these six patients were reviewed.RESULTS:Six patients underwent hepatic resection(n=5) or radio-frequency ablation(n=1) due to primary sHCC.Five cases had an R1 resection margin,and one case had an ablative margin less than 5.0 mm.No vascular infiltration,microsatellites or bile duct/canaliculus affection was noted in the initial resected specimens.During the follow-up,imaging studies revealed a macroscopic BDTT extending to the common bile duct in all six patients.Four patients had a concomitant intrahepatic recurrent tumor.Surgical re-resection of intrahepatic recurrent tumors and removal of BDTTs(n=4) ,BDTT removal through choledochotomy(n= 1) ,and conservative treatment(n=1) was performed.Microscopic portal vein invasion was noted in three of the four resected specimens.All six patients died,with a mean survival of 11 mo after BDTT removal or conservative treatment.CONCLUSION:BDTT occurrence is a rare,special recurrent pattern of primary sHCC.Patients with BDTTs extending to the common bile duct usually have an unfavorable prognosis even following aggressive surgery.Insufficient resection or ablative margins against primary sHCC may be a risk factor for BDTT development.

Numerical simulation on pressure-relief deformation characteristics of underlying coal-rock mass after upper protective layer excavation

Based on the occurrence features of Group B coal-seams at a coal mine in the Huainan coal mining area, the elasto-plastic mechanical damage constitutive functions and numerical model for the protective layer excavation were established. With the UDEC2D computer program, after the upper protective layer was mined, the stress field change trends, crack development, and expansion deformation trends of underlying coal rock seams in the floor of the working face were simulated and analyzed. The simulation results show the stress changes in coal rock seams, the evolution process of pre-cracks during the process of upper protective layer mining, the caved zone and fractured zone of the underlying coal rock seams. At the same time, the results from the actual investigation and analysis of protected layer deformation match the simulation values, which verifies the validity and accuracy of numerical simulation results. The study results have an important guiding significance for gas management in low permeability and high gas coal seams with similar mining conditions.

Slope Reinforcement for Housing in Three Gorges Reservoir Area

The Three Gorges Project of the Yangtze River is the largest hydropower-complex project under construction in the world. Under the largescale relocation projects, 2874 engineered slopes are formed along with the construction of new towns. In this paper, the cutting slopes are mainly soil slopes and rock slopes. Soil slopes include residual soil slopes, colluvial accumulation slopes, swelling soil slopes, and artificial earth fill slopes, etc. Rock slopes include blocky structure rock slopes, layer structure rock slopes, and clastic structure rock slopes, etc. Varied protection measures have been used for slope protection in the reservoir area including shotcrete concrete-anchor bars, frame beams, retaining walls, slope stabilizing piles, sheet-pile walls, anchorage anti-shear tunnels, flexible protection grids, and drainage, etc. Besides, slope deformation monitoring systems have been set up to monitor deformation failure and the stability state of slopes. The protection measures have guaranteed slope safety and maintained a harmony with the urban environment and surrounding landscape.

Investigation on adsorption and regeneration performances of multi-walled carbon nanotubes by supercritical water technique

In this paper, adsorption and regeneration characteristics of multi-walled carbon nanotubes （MWNTs） used as adsorbent were investigated for the removal of 1,3-beuzenediol （BDO） from water by the supercritieal water （SCW） technique. FFIR, XPS, SEM and dispersion stability tests were used to characterize the structure and surface morphology of CNTs. The results showed that CNTs surfaces were slightly activated and strongly etched in supercritieal water system. The adsorption capacity of SCW-treated CNTs was higher than that of raw CNTs. The adsorbed amounts for treated CNTs and raw CNTs samples at the same initial concentration of 60 mg/L were ca. 16.42 and 7.30 mg/g, respectively. The BDO adsorption of treated CNTs was due to the physical adsorption. The experimental data fit Freundlich isotherm model better than Langmuir one. The loaded adsorbent could be efficiently desorbed and regenerated by SCW technique. Therefore, SCW is a promising and environmentally friendly technique for the improvement of adsorption and regeneration of CNTs.

Effect of technological parameters on optical performance of fiber coupler

To find out the influence of technological parameters on optical performance of fused optical fiber device, the fiber coupler was served as subject investigated by using the fused biconical taper machining as experimental setup. Fused fiber coupler's optical performances such as insertion loss, excess loss, directivity and uniformity were tested with the optical test system that was constituted of tunable laser and optical spectrum analyzer. Especially the relationship between optical performance and drawing speed was investigated. The experimental results show that the optical performance is closely related to process conditions. At fused temperature of 1 200 ℃, there exists a drawing speed of 150 μms, which makes the device's performance optimum. Out of this speed region, the optical performance drops quickly. At drawing speed of 200 μms, the excess loss is relatively small when the fused temperature is above 1 200 ℃. So the technological parameters have close relationship with optical performance of the coupler, and the good performance coupler can't get until the drawing speed and fused temperature match accurately.

Short-term deformation behavior model of endangered earthen heritage slope after conservation in Jiaohe Ruins

Cliff deformation behavior after conservation is of great significance for evaluating the conservation effect and discovering the dynamical law of soil. Modeling on deformation behavior is beneficial to the quantitative evaluation of interactions between soil mass and structures as well as the forecast. Based on cliff conservation engineering of Jiaohe Ruins （the largest raw soil heritage site in the world）, data of horizontal deformation of the upper cliff were obtained by using Nanrui-made NDW-50 displacement device （precision： 0.01 mm, frequency： 15 min^-l）. Regression analysis indicates that deformation behavior models include exponential growth, linear growth and parabolic growth types, while daily deformation presents more intense periodicity （24 h）. The deformation is less than 1.5 mm during monitoring period, which has no impact on the stability of cliff. Deformation behavior provides the mutual duress and interaction between soil and engineering intervention. In addition, deformation mode attaches tensely to the damage pattern of the cliff. The conclusions are of importance to the stability evaluation of the carrier along Silk Road.

A Simple Bio-preservation Technique to Increase Shelf Life of Ampalavi Mango Fruits Using Aloe vera Gel

Aloe vera is being identified as a potential medicinal plant for its application in industries as well as traditional usage. The gel obtained from the leaves of A. vera has numerous properties. In this study, using the gel to extend the shelf life of Ampalavi mango fruits was studied. Even sized, uniform coloured, matured Ampalavi cultivar mango fruits were surface cleaned and coated with 33%, 66% and 100% gel, respectively. Results revealed that the ripening was delayed due to the coating. The total soluble solid （TSS）, pH and weight loss were high in uncoated fruits. The mean pH of the pulp from fruits kept as control was 4.94 at 4 d fruit preservation period （FPP） and was slightly increased to 5.43 within 12 d FPP, whereas the minimal pH （4.69 at 4 d FPP and 5.03 at 9 d FPP） was noticed in 100% gel coated fruits. The TSS （brix） was significantly in higher levels （13.67°Bx within 4 d FPP and 20.77°Bx within 12 d FPP） in control fruits, whereas the minimum TSS value was 9.27°Bx and 18.03° Bx within 4 d and 12 d FPP, respectively, recorded from the 100% gel coated fruits in storage. The weight loss percentage （WLP） was significantly （P 〈 0.05） higher in control fruits （8.46%）, whereas the lower WLP （1.13%） was found in 100% gel coated fruits after 12 d of storage. This low-scale gel coating technique prolonged the fruits shelf life by delaying the fruit ripening. This effect has to be further investigated to commercialize the natural product for large scale ready-made application.