秦二世直道行迹与望夷宫“祠泾”故事

《史记》卷六《秦始皇本纪》记载,公元前210年,秦始皇在东巡途中驾崩,赵高、李斯、胡亥策划沙丘政变,将棺载在辒凉车中,经直道返回咸阳。随后胡亥即帝位。这是秦二世胡亥经行直道的明确记载。秦二世元年(前209),由李斯、冯去疾等随从往东方巡行。"遂至辽东而还""还至咸阳",很可能再次行经直道。致使望夷宫之变发生的"二世梦白虎啮其左骖马"及"斋于望夷宫,欲祠泾"事,或许也与直道交通有关。

CHARACTERISTICS OF FLOW IN A PARTIALLY DYNAMIC HELICOPTER INLET

An experimental study of the flow in a helicopter inlet with front output shaft and partial flow dynamic head is conducted in low speed wind tunnel. The flow characters of the inlet in the range of the yaw angle from 0~135°are presented in this paper. The static pressure distributions along the duct, distortions of the flow field at the outlet section and total pressure recovery coefficients are measured and analyzed. The results show that this type of inlet has high total pressure recovery coefficients at a wide range of yaw angle. The regions of local flow separation and distortion are closely related to the yaw angle. It′s also found that the outlet section has the best characteristics at sideslip, and sharply deteriorated characteristics at the yawed flight with a yaw angle of more than 90°

流血的经济

战争是流血的政治,这是政治家的语言。但是,我们不应该忘记,战争也是流血的经济。尽管政治家们不这么说,但比较日本两次发动侵华战争,即100年前的甲午战争和50年前的侵华战争,就不难明白这一点。甲午战争,日本打胜了,中国打败了。八年抗战,中国打胜了,日本打败了。用经济眼光看这两次战争,中国的败是彻底地败,中国的胜实际还是败;日本的胜是彻底地胜,日本的败实际还是胜。甲午战争,八年抗战,一败一胜,只是结束的形式不同,就中国人民遭受的巨大经济损失讲,就日本对中国财富的掠夺讲,却没有什么不同。

AERODYNAMIC ANALYSIS OF HELICOPTER SHROUDED TAIL ROTOR BY MOMENTUM THEORY

In this paper, in order to clarify the gains of the shroud in the shrouded tail rotor system, a thrust division factor q , which represents the ratio of the shroud thrust to the total thrust of the shrouded tail rotor, is introduced. With the help of q , the slipstream theory for the static and axial flow states of the shrouded tail rotor are fully derived. Based on the sliptream theory, the variations of the thrust, power and disk area against q for different cases are emphatically analysed and the comparisons between a shrouded tail rotor and an isolated one are made. It is shown that, although the shroud can provide as much as 50% of the total thrust of shrouded tail rotor for the static state, the thrust gains of the shroud rapidly decrease for the axial flow state, which depends on the flow velocity ratio.

加强日中两国古道的学术交流——在第四届蜀道及石门石刻国际学术讨论会开幕式上的讲话

一千二百多年前,唐代诗人李白描写蜀道之难说:“蜀道之难难于上青天”.今天,我参加这次蜀道及石门石刻国际学术讨论会,不能不感慨万端.从我开始研究生活起,有过一段与贵国学者不能进行学术交流的时期,其困难确象“蜀道难”一样,“难于上青天”的.

Ab initio Study on Ionization Energies of 3-Amino-1-propanol

Fourteen conformers of 3-amino-1-propanol as the minima on the potential energy surface are examined at the MP2/6-311＋＋G＊＊ level. Their relative energies calculated at B3LYP, MP3 and MP4 levels of theory indicated that two most stable conformers display the intramolecular OH - N hydrogen bonds. The vertical ionization energies of these conformers calculated with ab initio electron propagator theory in the P3/aug-cc-pVTZ approximation are in agreement with experimental data from photoelectron spectroscopy. Natural bond orbital analyses were used to explain the differences of IEs of the highest occupied molecular ortibal of conformers. Combined with statistical mechanics principles, conformational distributions at various temperatures are obtained and the temperature dependence of photoelectron spectra is interpreted.

Dynamics of vertical pipe in deep-ocean mining system

A 3-D geometrical nonlinear model for the entire lift system of 1000-m sea trial system of China Ocean Mineral Resources R&D Association was established with finite element method.The model was utilized to analyze the dynamic characteristics of the vertical pipe under the influence of moving velocity,current direction and wave.The simulation results show that the axial stress is dominant on the vertical pipe,its maximum is located at the pipe top,all stresses are much less than the allowable value of the vertical pipe and joint;the heave motion leads to violent fluctuation of the force and stress,but a period of 8 s is not likely to resonate the present pipe;against the current,0.50 m/s is the suggested moving velocity of the ship and miner,while along the current,the moving velocity can be slightly higher than 0.75 m/s.

Flow measurement and parameter optimization of right-angled flow passage in hydraulic manifold block

This study was conducted to investigate the flow field characteristics of right-angled flow passage with various cavities in the typical hydraulic manifold block.A low-speed visualization test rig was developed and the flow field of the right-angled flow passage with different cavity structures was measured using 2D-PIV technique.Numerical model was established to simulate the three-dimensional flow field.Seven eddy viscosity turbulence models were investigated in predicting the flow field by comparing against the particle image relocimetry(PIV)measurement results.By defining the weight error function K,the S-A model was selected as the appropriate turbulence model.Then,a three-factor,three-level response surface numerical test was conducted to investigate the influence of flow passage connection type,cavity diameter and cavity length-diameter ratio on pressure loss.The results show that the Box-Benhnken Design(BBD)model can predict the total pressure loss accurately.The optimal factor level appeared in flow passage connection type II,14.64 mm diameter and 67.53%cavity length-diameter ratio.The total pressure loss decreased by 11.15%relative to the worst factor level,and total pressure loss can be reduced by 64.75%when using an arc transition right-angled flow passage,which indicates a new direction for the optimization design of flow passage in hydraulic manifold blocks.

Channel characteristics analysis of train-to-train wireless communication

Train-to-train(T2T)communication can provide protection for existing train-to-ground private network communication,and its channel characteristics directly affect the application of upper-layer communication technologies.In this study,based on the spatial distribution structure of railway operation scenarios and Fresnel zone theory,we propose a frequency allocation scheme for direct communication between tracking trains in flatland and long straight tunnel scenario.Then we use the estimation method of radio wave attenuation caused by rainfall to analyze the large-scale path loss fading of multi-band wireless channels.Furthermore,we derive the calculation equation of max Doppler frequency shift suitable for T2T communication and describe the multipath wave in the tunnel by ray tracing method to analyze small-scale fading.Simulation analysis shows that the Doppler shift value of T2T communication low frequency band is significantly lower than the frequency shift value of the train-to-ground communication under the same speed conditions.

Current treatment of rectovaginal fistula in Crohn's disease

Rectovaginal fistula(RVF) continues to be the most difficult perianal manifestation of Crohn's disease to treat.This devastating and disabling complication has a significant impact on patients' quality of life and presents unique management challenges.Current therapeutic approaches include many medical therapeutics and surgical treatments with a wide range of success rates reported.However,current evidence is lacking to support any recommendation.The choice of repair depends on various patient and disease factors and basic surgical tenets.In this article,we review the current options to consider in the treatment of Crohn's-related RVF,and try to evaluate their effects on fistulae closure and quality of life.

Gastrointestinal stromal tumour of the rectum: Report of a case and review of literature

Gastrointestinal stromal tumour （GIST） is a rare tumour of the gastrointestinal tract which does not generally originate in the rectum. The authors describe a case of a 70-year-old man who underwent an anterior resection of the rectum for a low-risk GIST. The patient was not given adjuvant chemotherapy with imatinib and is still disease-free 30 mo after surgery. The authors conclude that although rectal GIST is extremely uncommon, it should be included in differential diagnosis when a tumour in the rectum is detected. Biopsy of the tumour is essential, since this makes it possible to reach a sure preoperative diagnosis based on the immunohistological features of the CDl17 and CD34. Although complete surgical resection with negative tumour margins is the principal curative procedure for primary and nonmetastatic tumours, further studies are still needed for the determination of the most effective treatment strategy for patients with rectal GIST.

Indirect heat integration across plants using hot water circles

Total site heat integration(TSHI) provides more opportunities for energy saving in industry clusters. Some design methods including direct integration using process streams and indirect integration using intermediate-fluid circuits, i.e., steam, dowtherms and hot water, have been proposed during last few decades. Indirect heat integration is preferred when the heat sources and sinks are separated in independent plants with rather long distance. This improves energy efficiency by adaption of intermediate fluid circle which acts as a utility provider for plants in a symbiotic network. However, there are some significant factors ignored in conventional TSHI, i.e. the investment of pipeline, cost of pumping and heat loss. These factors simultaneously determine the possibility and performance of heat integration. This work presents a new methodology for indirect heat integration in low temperature range using hot water circuit as intermediate-fluid medium. The new methodology enables the targeting of indirect heat integration across plants considering the factors mentioned earlier. An MINLP model with economic objective is established and solved. The optimization results give the mass flow rate of intermediate-fluid, diameter of pipeline, the temperature of the circuits and the matches of heat exchanger networks(HENS) automatically. Finally, the application of this proposed methodology is illustrated with a case study.

Measuring the space between vagina and rectum as it relates to rectocele

AIM:To measure the normal space between the posterior wall of the vagina and the anterior wall of the respectively rectum using computed tomography(CT) and reveal its were relationship to rectocele. METHODS:A total of twenty female volunteers without rectocele were examined by CT scan.We performed a middle level continuous horizontal pelvic scan from the upper part to the lower part and collected the measurement data to analyze the results using t-test. RESULTS:Twenty volunteers were enrolled in the study. The space between the posterior wall of the vagina and the anterior wall of the rectum was measured at three levels(upper 1/3,middle,lower 1/3 level of vagina). The results showed that the space from the posterior wall of the vagina to the anterior wall of the rectum at the upper 1/3 level and the middle level was 3.896 ±0.3617 mm and 4.6575±0.3052 mm,respectively. When the two groups of data were compared,we found the space at the upper 1/3 level was shorter than at the middle level(P<0.01).Moreover,at the lower 1/3 level the space measured was 10.058±0.4534 mm.The results revealed that the space at the lower 1/3 level was longer than that at the middle level(P<0.01). CONCLUSION:These measurement data may be helpful in assessing rectocele clinical diagnosis and functional outcomes of rectocele repair.

Hydrogen-bonding Interaction of 1,2,3-triazine-waters Complexes

Density functional theory B3LYP method with 6-31＋＋G＊＊ basis was used to optimize the geometries of the ground states for 1,2,3-triazine-（H2O）n（n=1,2,3） complexes. All calculations indicate that the 1,2,3- triazine-water complexes in the ground states have strong hydrogen-bonding interaction, and the complex having a N… .H-O hydrogen bond and a chain of water molecules which is terminated by a O. … .H-C hydrogen bond is the most stable. The H-O stretching modes of complexes are red-shifted relative to that of the monomer. In addition, the Natural bond orbit （NBO） analysis indicates that the intermolecular charge transfer between 1,2,3-triazine and water is 0.0222e, 0.0261e and 0.0273e for the most stable 1：1, 1：2 and 1：3 complexes, respectively. The first singlet （n, π＊） vertical excitation energy of the monomer 1,2,3-triazine and the hydrogen-bonding complexes of 1,2,3-triazine-（H2O）n were investigated by time-dependent density functional theory.

Comprehensive Treatment and Prognostic Factors in Patients with Carcinoma of the Cervical Stump

OBJECTIVE To evaluate the applicability of combined therapyand the prognostic factors in patients with carcinoma of thecervical stump (CCS).METHODS The clinical records of 60 CCS patients whounderwent combined treatment in our hospital during a periodfrom January 2000 to December 2007, were collected andretrospectively analyzed. The prognostic factors were studiedusing univariate analysis. Analytical evaluation of the independentprognostic factors was performed using COX proportionalhazardsregression model.RESULTS The 1-, 3- and 5-year survival rates of the 60 patientswere 95%, 78% and 68%, respectively, with a median survivaltime of 32 months. Univariate survival analysis showed thatthese independent prognostic factors included positive pelviclymph nodes (P = 0.001), lymphovascular tumor embolus (P =0.001), and adjuvant chemotherapy (P = 0.011). In the 60 cases,postoperative local recurrence in the pelvic cavity occurred in1 and distant metastasis in 3. Related complications, such asradiocystitis, recto-vaginal fistula and vesico-vaginal fistula werefound in 6 of the total cases (10%). The serum levels of squamousepithelium antigen detected before and after treatment weresignificantly different (P = 0.000). The incidence of CCS is low;however, the disease is difficult to cure due to the high incidenceof complications and to the frequency of distant metastasis.Therefore, individualized treatment is needed. Complications fromsubtotal hysterectomy (STH) should be treated and controlledaggressively. Careful follow-up as well as close monitoring andobservation for significant symptoms in the postoperative coursewill enhance clinical outcome.CONCLUSION Cancer of the cervical stump has a lowmorbidity and severe complications, and most recurrences aredistant metastases. Because it is difficult to cure, there is a needto design a treatment regimen for each individual patient basedon the factors deemed as high risk. The surgical indications forsubtotal uterine resection should be followed and close follow-upafter surgery should be maintained.

Effects of gully terrain on stress field distribution and ground pressure behavior in shallow seam mining

This study proposes a novel approach to study stress field distribution and overlying ground pressure behavior in shallow seam mining in gully terrain.This approach combines numerical simulations and field tests based on the conditions of gully terrain in the Chuancao Gedan Mine.The effects of gully terrain on the in situ stress field of coal beds can be identified by the ratio of self-weight stress to vertical stress(η) at the location corresponding to the maximum vertical stress.Based on the function η =j(h),the effect of gully terrain on the stress field of overlying strata of the entire field can be characterized as a significantly affected area,moderately affected area,or non-affected area.Working face 6106 in the Chuancao Gedan Mine had a coal bed Jepth <80 m and was located in what was identified as a significantly affected area.Hence,mining may cause sliding of the gully slope and increased loading(including significant dynamic loading) on the roof strata.Field tests suggest that significant dynamic pressures were observed at the body and foot of the gully slope,and that dynamic loadings were observed upslope of the working face expansion,provided that the expanding direction of the working face is parallel to the gully.

An adult case of celiac sprue triggered after an ileal resection for perforated Meckel's diverticulum

Celiac disease can be triggered by upper abdominal surgery, such as vagotomy, oesophagectomy, pancreatico-duodenectomy, and gastrojejunal anastomosis. Here we report a case of a 24 year-old woman who developed celiac disease after an ileal resection for perforated Meckel's diverticula. This is the first reported celiac case that has been triggered, not by upper abdominal surgery, but after ileal resection for Meckel's diverticula.

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.

Perpendicular intergrowth ZSM-5 plates with shortened 10-MR pores

ZSM-5 plates with a perpendicular intergrowth structure was synthesized by using a simple amine as the structure directing agent under hydrothermal conditions,in which the mother plate and the perpendicularly standing plates oriented along the(010)and(100)planes of MFI crystals,respectively.During the crystallization process,the mother plate was initially formed on the surface of the amorphous solid gel,while a set of parallel plates perpendicularly grew on its surface,via a homogeneous nucleation mechanism.The mother plate and the perpendicular plates had a similar thickness of 100-200 nm and were characterized by considerably shortened straight and zigzag 10 member ring pores,respectively.This unique intergrowth structure greatly facilitated the diffusion of the reactive molecules in HZSM-5 crystals during methanol conversion to hydrocarbons.