复合胶凝材料组成与混凝土抗压强度定量关系研究

通过单纯形重心设计方法得出了水泥磨细矿渣微粉超细粉煤灰三元复合胶凝材料组成与各龄期混凝土抗压强度的定量数学解析式 ,其对混凝土强度的预测精度基本可控制在 5 %的相对误差范围内 .不同龄期三元系统的等强线变化揭示了 3d和 2 8d时 ,复合胶凝材料各组分对强度的贡献按水泥、磨细矿渣微粉、超细粉煤灰的顺序降低 ,1 80d时则按水泥、超细粉煤灰、磨细矿渣微粉的顺序降低 。

测磁传感器数据计算及可视化研究

为增强舰船的磁性防御能力需要定时对其进行消磁处理,这就要求技术人员在舰船消磁工程中准确,迅速地分析测磁传感器数据。该文模拟点阵式大平面法采集的测磁传感器数据,依照舰船磁场的磁偶极子阵列数学模型实现磁场数据的深度换算;将空间点阵式的磁偶极子阵列模型数据转化为2D数组数据,进行模型的空间面显示;利用磁场-灰度映射关系实现模型的4D可视化描述,为优化舰船磁场模型提供了准确且直观的依据;通过对测量面和换算面磁场数据的可视化描述,绘制其3D视图、等强线图和剖面图,为消磁技术人员监控测磁传感器工作和进行消磁电流决策,消磁效果评价提供了有力依据。

扫雷舰非接触磁扫雷编队参数设置及磁场分析

在编队扫雷作业中,如何使编队的队形参数和扫雷工作制度合理化,从而得到较好的扫雷效率,是急需解决的课题。从扫雷具磁场分析入手,通过扫雷编队在不同条件下的仿真计算绘制了等强线,并给出了最佳舰间距的计算方法;讨论了队形误差和不同工作制度参数设置对扫雷可靠性的影响。最后得出必须根据扫雷训练的实际情况并考虑多种因素的的影响来制订科学合理的扫雷计划,编队扫雷才能获得较好的效果。

Time-temperature-property curves for quench sensitivity of 6063 aluminum alloy

The quench sensitivity of 6063 alloy was investigated via constructing time-temperature-property（TTP） curves by interrupted quenching technique and transmission electron microscopy（TEM） analysis.The results show that the quench sensitivity of 6063 alloy is lower than that of 6061 or 6082 alloy,and the critical temperature ranges from 300 to 410℃ with the nose temperature of about 360℃.From TEM analysis,heterogeneous precipitate β-Mg2Si is prior to nucleate on the（AlxFeySiz） dispersoids in the critical temperature range,and grows up most rapidly at the nose temperature of 360℃.The heterogeneous precipitation leads to a low concentration of solute,which consequently reduces the amount of the strengthening phase β＇＇ after aging.In the large-scale industrial production of 6063 alloy,the cooling rate during quenching should be enhanced as high as possible in the quenching sensitive temperature range（410-300℃） to suppress the heterogeneous precipitation to get optimal mechanical properties,and it should be slowed down properly from the solution temperature to 410℃ and below 300℃ to reduce the residual stress.

Application of Image Enhancement Techniques to Potential Field Data

In this paper the application of image enhancement techniques to potential field data is briefly described and two improved enhancement methods are introduced. One method is derived from the histogram equalization technique and automatically determines the color spectra of geophysical maps. Colors can be properly distributed and visual effects and resolution can be enhanced by the method. The other method is based on the modified Radon transform and gradient calculation and is used to detect and enhance linear features in gravity and magnetic images. The method facilites the detection of line segments in the transform domain. Tests with synthetic images and real data show the methods to be effective in feature enhancement.

Impacts of bird abundance, activity height and light intensity on the number of birds captured by mist netting

To understand better the impact on mist net capture rates of the activity height of birds, light intensity, bird richness and abundance, we compared data from mist nets and point counts at the Jianfengling Forest Area, Hainan Island. Mist-nets were operated for a total of 7135 net-hours. A total of 587 individuals of 45 bird species were captured. The total mean capture rate was 8.6 ± 10.4 per 100 net-hours. A total of 4932 individuals of 107 bird species were recorded by visual observation alone and 7616 individuals of 120 species were recorded in a visual and aural combination. The Grey-cheeked Fulvetta (Alcippe morrisonia) was the most abundant species, accounting for 38.7% of total captures, 27.9% of visual observations and 22.2% of visual + aural observations. The capture number was correlated with the number observed. Thirty-one species were more likely to be captured than observed. Canopy species, such as members of the Corvidae and Dicruridae, were seldom captured. For all ground feeding species, the capture number was greater than that of observation. Some cryptic species, such as the Lesser Wren Babbler (Napothera epilepidota), Spotnecked Babbler (Stachyris striolata) and Cuckoo Owl (Glaucidium cuculoides) also had a higher relative capture rate than that of observations. There was a significant relationship between light intensity and the number of birds captured.

Novel p-Channel Selected n-Channel Divided Bit-Line NOR Flash Memory Using Source Induced Band-to-Band Hot Electron Injection Programming

A novel p-channel selected n-channel divided bit-line NOR(PNOR) flash memory,which features low programming current,low power,high access current,and slight bit-line disturbance,is proposed.By using the source induced band-to-band hot electron injection (SIBE) to perform programming and dividing the bit-line to the sub-bit-lines,the programming current and power can be reduced to 3.5μA and 16.5μW with the sub-bit-line width equaling to 128,and a read current of 60μA is obtained.Furthermore,the bit-line disturbance is also significantly alleviated.

计算机在X射线物相分析中的应用

x射线衍射是研究物质的精细结构的十种工具,这种技术是劳厄在1921年发现了晶体能衍射x射线,并由其衍射的方向揭露出晶体的结构而开始的,起初,x射线衍射系单纯用来测定晶体的结构,但其后则发展了其它用途。至今这种方法不法不但可以用来测定结构,并且还可用来解决像化学分析,应力测量,相平衡的研究,微粒大小的测量,单晶体的取向或多晶聚合体中各种取向总体的测定等各种问题。

Comparison among Growth, Photosynthesis and Yield in Nanjing 9108 and Its Parents during the Late Development Stage

A good quality, high yield, slow mature and middle season Japonica rice variety, Nanjing 9108 and its parents Guandong 194 and Wuxiangjing 14,were taken as the materials for the study. The growth and photosynthetic characteristics of the rice plants at the post-flowering stage were compared and the rice yield components were examined at harvest. The results showed that as compared with Wuxiangjing 14, the per plant yield of Nanjing 9108 was 7.70% higher, and much higher than that of Guandong194. The large total grain per plant and heavy grain weigh of Nanjing 9108 were the important structure basis for its yield. Further analysis o the growth indicators showed that Nanjing 9108 had a large leaf area of upper three green leaves area and a smaller leaf base angle in the third leaf from the bottom blades, which helped get a higher photosynthetic capacity in groups. On the14 thday after flowering, Nanjing 9108 had similar value of net photosynthetic rate（Pn） to that of Wuxianjing 14, but lower than that of Guandong 194. Viewing from the parameters obtained from light response of photosynthesis on the modified model of rectangular hyperbola, Pn of Nanjing 9108 was more aptated to be saturated by light intensity and sensitive to photoinhibition. On the whole, Nanjing 9108 with high yield mainly resulted from its good plant type, grain structure and higher photosynthetic capacity in groups. Further improving its photosynthetic capacity o single leaf in Nanjing 9108 would be an important way for its super high yield po tential in the future.

维生素E治疗翼状胬肉

自1992年以来,我们试用维生素E治疗翼状胬肉81例,收到满意的效果。其中,男70例,女11例,年龄19～52岁。1 治疗及效果 1.1 用药方法:均以口服维生素E为主,每次200mg,每日3次。根据充血轻重连续用3～7天,24小时内作冷敷,24小时后作热敷。 1.2 结果:3～5天内症状消失者达85％以上,一周内消失者占20％,总有效率达98％。不良反应有胃肠道表现,如恶心、食欲不振等,治疗期间未出现其它毒副反应。2

ENHANCED UNSTEADY AND NONLINEAR ROTOR WAKE MODEL FOR REAL-TIME FLIG HT SIMULATION

WT5 'BZThis paper presents an unsteady and nonlinear wake model based on th e widely used Peters He finite state dynamic wake model with improvements. The swirl component in the tip trace plane (TTP) can be predicted, nonlinear items are added into the linear theory, and the old small angle assumption use d in matrix prediction is removed. All of these enha ncements are aimed at the low speed flight phase and formulations for the induce d velocity field just in the TTP frame are derived. The corresponding FORTRAN pr ogram is tested and optimized for the real time applications on PCs.

Dynamic caustics experimental study on interaction between propagating crack and deformity inclusions in primary structure

The approach combining the dynamic caustics method with high-speed photography technology is used to study the interaction between propagating cracks and three kinds of deformity inclusions（ cylinder inclusion, quadruple inclusion and triangular inclusion） under lowvelocity impact loading. By recording the caustic spots of crack tips at different moments during the crack propagation, the variation regulations of dynamic stress intensity factors（ DSIF） and crack growth velocity with respect to time are obtained. The experimental results showthat the resistance effects to crack growth are varied with different shapes of inclusions in specimens, and the quadruple inclusion＇s effect is more apparent. The distortion degree of caustic spots is affected by the shapes of inclusions as well, and the situation is more serious for cylinder and quadruple inclusions. The overall values of DSIFs of triangular inclusion specimen are greater than the others, and the crack growth velocities, characteristic sizes and DSIFs showprocesses of fluctuations because of the disturbance of reflection waves in specimens. The results provide an experimental basis for the analysis of strength and impact-resistance ability in structures with deformity inclusions.

Positioning planning of high-intensity-focused ultrasound surgery platform using Bezier curve

A positioning volume ellipsoid method is proposed to represent tumor volume in the workspace of a high-intensity-focused ultrasound (HIFU) surgery platform during the platform's positioning motion. To this simplified tumor model, a nearest neighbor search method is used to determine intermediate configuration and goal configuration, which the treatment head and ultrasound focus must pass in their localization to target volume. Based on the decided configurations, the continuity condition of combined Bezier curve in Euclidean space and De Casteljau algorithm on Lie group SO(3) are integrated to construct a combined Bezier positioning path of C2 continuity at junctional configuration, and an illustration of different positioning path planning is analyzed based on a liver tumor case.

A Class of Strongly Nonlinear Singular Perturbed Boundary Value Problems

In this paper, a class of strongly nonlinear singular perturbed boundary value problems are coasidered by the theory of differential inequalities and the correction of boundary layer, under which the existence of solution is proved and the uniformly valid asymptotic expansions is obtained as well.

Nonlinear Model Algorithmic Control of a pH Neutralization Process

Control of pH neutralization processes is challenging in the chemical process industry because of their inherent strong nonlinearity. In this paper, the model algorithmic control (MAC) strategy is extended to nonlinear processes using Hammerstein model that consists of a static nonlinear polynomial function followed in series by a linear impulse response dynamic element. A new nonlinear Hammerstein MAC algorithm (named NLH-MAC) is presented in detail. The simulation control results of a pH neutralization process show that NLH-MAC gives better control performance than linear MAC and the commonly used industrial nonlinear propotional plus integral plus derivative (PID) controller. Further simulation experiment demonstrates that NLH-MAC not only gives good control response, but also possesses good stability and robustness even with large modeling errors.

Active Fault Tolerant Control of a Class of Nonlinear Time-Delay Processes

Based on a nonlinear state predictor (NSP) and a strong tracking filter (STF), a sensor fault tolerant generic model control (FTGMC) approach for a class of nonlinear time-delay processes is proposed. First, the NSP is introduced, and it is used to extend the conventional generic model control (GMC) to nonlinear processes with large input time-delay. Then the STF is adopted to estimate process states and sensor bias, the estimated sensor bias is used to drive a fault detection logic. When a sensor fault is detected, the estimated process states by the STF will be used to construct the process output to form a 'soft sensor', which is then used by the NSP (instead of the real outputs) to provide state predictors. These procedures constitute an active fault tolerant control scheme. Finally, simulation results of a three-tank-system demonstrate the effectiveness of the proposed approach.

Pancreatic carcinoma coexisting with chronic pancreatitis versus tumor-forming pancreatitis:Diagnostic utility of the time-signal intensity curve from dynamic contrast-enhanced MR imaging

AIM: To evaluate the ability of the time-signal intensity curve (TIC) of the pancreas obtained from dynamic contrast-enhanced magnetic resonance imaging (MRI) for differentiation of focal pancreatic masses, especially pancreatic carcinoma coexisting with chronic pancreatitis and tumor-forming pancreatitis. METHODS: Forty-eight consecutive patients who underwent surgery for a focal pancreatic mass, including pancreatic ductal carcinoma (n = 33), tumor-forming pancreatitis (n = 8), and islet cell tumor (n = 7), were reviewed. Five pancreatic carcinomas coexisted with longstanding chronic pancreatitis. The pancreatic TICs were obtained from the pancreatic mass and the pancreatic parenchyma both proximal and distal to the mass lesion in each patient, prior to surgery, and were classified into 4 types according to the time to a peak: 25 s and 1, 2, and 3 min after the bolus injection of contrast material, namely, type-Ⅰ, Ⅱ, Ⅲ, and Ⅳ, respectively, and were then compared to the corresponding histological pancreatic conditions. RESULTS: Pancreatic carcinomas demonstrated type-Ⅲ (n = 13) or Ⅳ (n = 20) TIC. Tumor-forming pancreatitis showed type-Ⅱ (n = 5) or Ⅲ (n = 3) TIC. All islet cell tumors revealed type-Ⅰ. The type-Ⅳ TIC was only recognized in pancreatic carcinoma, and the TIC of carcinoma always depicted the slowest rise to a peak among the 3 pancreatic TICs measured in each patient, even in patients with chronic pancreatitis.CONCLUSION: Pancreatic TIC from dynamic MRI provides reliable information for distinguishing pancreatic carcinoma from other pancreatic masses, and may enable us to avoid unnecessary pancreatic surgery and delays in making a correct diagnosis of pancreatic carcinoma, especially, in patients with longstanding chronic pancreatitis.

Evaluation of small bowel blood flow in healthy subjects receiving low-dose aspirin

AIM:To investigate the relationship between low-dose aspirin-induced small bowel mucosal damage and blood flow,and the effect of rebamipide. METHODS:Ten healthy volunteers were enrolled in this study.The subjects were divided into two groups:a placebo group given low-dose aspirin plus placebo and a rebamipide group given low-dose aspirin plus rebamipide for a period of 14 d.Capsule endoscopy and contrast-enhanced ultrasonography were performed before and after administration of drugs.Areas under the curves and peak value of time-intensity curve were calculated. RESULTS:Absolute differences in areas under the curves were-1102.5(95%CI:-1980.3 to-224.7,P=0.0194) in the placebo group and-152.7(95%CI:-1604.2 to 641.6,P=0.8172) in the rebamipide group. Peak values of time intensity curves were-148.0(95% CI:-269.4 to-26.2,P=0.0225) in the placebo group and 28.3(95%CI:-269.0 to 325.6,P=0.8343) in the rebamipide group.Capsule endoscopy showed mucosal breaks only in the placebo group. CONCLUSION:Short-term administration of low-dose aspirin is associated with small bowel injuries and blood flow.

Study on High-Temperature Spectra of Asymptotic Asymmetric-Top Molecule O_3

The line intensities of 001-000 transition of the asymptotic asymmetric-top Oa molecule at several temperatures are calculated by directly calculating the partition functions and regarding the rotationless transition dipole moment squared as a constant. The calculated values of the total internM partition sums （TIPS） are consistent with the data of HITRAN database with -0.61% at 296 K. The calculated line intensity data at 500 K and 3000 K are also in excellent agreement with the data in HITRAN database with less than 0.659% and 5.458% at 500 K and 3000 K, which provide a strong support for the calculations of partition function and fine intensity at high temperature. Then we extend the calculation to higher temperatures. The line intensities and simulated spectra of v3 band of the asymptotic asymmetric-top O3 molecule at 4000 and 5000 K are reported. The results are of significance for the studying of the molecular high-temperature spectrum including experimental measurements and theoretical calculations.