10大关键单反技巧

无论你是刚刚学习摄影的新手,还是处于瓶颈期的老手,重新开始学习基础知识,都能给你带来新的突破。现在就让Chris Rutter给大家提供十条能够提高自己拍摄水平的必备技巧。或许数十年的磨练,才能带来一幅精彩的作品;但无论水平高低,掌握一些基础的摄影技巧或许就能拍摄出让人刮目相看的照片。接下来,我们就打算向大家介绍十条每个摄影师都应该掌握的基础拍摄技巧,从对焦到构图、从白平衡到光线条件,一针见血地指出初学者的常见问题,提高对于基本技巧的掌握,帮助大家使用最简单的方     

A general methodology for bearing design in non-symmetric T-shaped sections in extrusion process

In this study, a general methodology has been developed to design the proper bearing in order to eliminate the curvature of the final product in extrusion process. Three smooth curved (advanced-surface) dies with non-symmetric T-shaped sections and different off-centricities have been studied. For each die, the proper bearing has been designed and physical and numerical modeling have been performed to validate the design. The design procedure is as follows: A formulation, based on Bezier curves, has been used to determine the exit velocity profile. Since the result of Bezier method is different from the actual velocity profile, the Chitkara corrective function has been modified and applied to improve the velocity field. A deviation function has been developed to measure the curvature of the final product in terms of the exit velocity field. Considering the obtained velocity field, the friction effects, and the geometry of the dies, the proper bearing for each die has been designed. Finally, numerical and physical modeling have been performed on the die-bearing combination. According to the results, the curvature of the final product was eliminated to a great extent.     

如何让你的照片充满活力

<正>本期重点:1使用仿制图章工具2转换黑白影调和调整反差3调整画面影调与色彩4调整高光与增加细节5使用蒙版工具强化色彩和反差6调整构图与使用可选颜色7使用自由变换与调节曲线一张优秀的照片如何脱颖而出?是什么让它显得与众不同?如果你需要建议让自己的照片变得出色,我们的专家很乐意在此提供     

DSC Study of Solid-Liquid Equilibria for Energetic Binary Mixtures of Methylnitramine with 2,4-Dinitro-2,4-diazapentane and 2,4-Dinitro-2,4-diazahexane

Binary phase diagrams for two mixtures of methylnitramine (1) + 2,4-dinitro-2,4-diazapentane (2) (eutectic temperature T _E = 285.1 K, eutectic composition x ₁ = 0.565) and methylnitramine (1) + 2,4-dinitro-2,4-diazahexane (2) (eutectic temperature T _E = 280.3 K, eutectic composition x ₁ = 0.653) were studied using differential scanning calorimetries (DSC). For both systems simple eutectic behavior was observed. The eutectic compositions were also determined using Gray’s model and the fractional transformation method.     

拉直倾斜的建筑

<正>George Cairns告诉我们如何使用镜头校正命令完善建筑摄影作品我们敢打赌大部分建筑都有拔地而起的90度垂直外墙。但是在拍摄建筑物照片的时候,由于透视畸变,所有垂直线条向一点汇聚,外墙的下半部分往往要比上半部分看上去宽很多。     

The alpha attenuation test: assessing excessive daytime sleepiness in narcolepsy-cataplexy

Daytime sleep tendency was assessed in 10 drug-free patients with narcolepsy-cataplexy and 10 normals matched for age and gender. Following nocturnal polysomnography, the alpha attenuation test (AAT) and the multiple sleep latency test (MSLT) were administered during five sessions occurring at 2-hour intervals beginning at 0900 and 1000 hours, respectively. For the AAT, participants were polysomnographically recorded for 8 minutes while seated in an illuminated room with their eyes alternately opened and closed. Power spectral analyses of electroencephalograph (EEG) activity at 02-A1 (10 second epochs) were calculated using fast Fourier transformations (FFT) within the alpha frequency range (8-12 Hz) to obtain ratios of mean eyes-closed to mean eyes-open alpha power (i.e. the alpha attenuation coefficient, AAC). The narcoleptics were sleepier than the normals as indicated by a significantly smaller mean AAC and a significantly shorter mean latency to stage 1 on the MSLT. These findings suggest that the AAT may provide a quick and practical objective assessment of the excessive daytime sleepiness (EDS) associated with narcolepsy.     

Osteopenia in children surviving brain tumours

Mature and post-translational precursor gastrin forms are growth factors for colorectal tumours. The immunogen Gastrimmune is composed of the amino terminus of gastrin-17 linked to diphtheria toxoid and raises antibodies in situ which neutralise amidated and glycine-extended gastrin-17. The aim of the study was to determine the effect of treatment with 5-fluorouracil(5-FU)/leucovorin on the antibody titres induced by Gastrimmune and the effect of combination therapy on the growth of the rat colon tumour DHDK12. Gastrimmune was administered to rats s.c. at 3 weekly intervals. The rat colon tumour line DHDK12 was injected into the abdominal wall of BDIX rats. Combinations of 5-FU/leucovorin were injected i.v. on days 1, 3 and 5, with the cycle repeated every 4 weeks. Antibody titres were measured by an ELISA technique. Antibody titres were followed for 40 weeks after Gastrimmune (500 microg.ml(-1)) immunization, with titres peaking between 10 and 20 weeks after a single immunisation and falling by week 30. At termination, no effect was observed on either the histological appearance of the gastro-intestinal tract or the proliferation of the colonic mucosa. Pre- and post-treatment with 5-FU/leucovorin (30 mg.kg(-1)) had no effect on the kinetics and level of antibody response to Gastrimmune. Gastrimmune (200 microg.ml(-1)) and 5-FU/leucovorin combinations (12.5 and 20 mg.kg(-1)) increased the therapeutic effects on the in vivo growth of DHDK12 tumors when compared to the agents given singly. Gastrimmune immunisation may be a therapeutic option for the treatment of colorectal cancer in combination with 5-FU/leucovorin.