四

Competition among four-wave mixing with two dressing fields, the six-wave mixing with one dressing field as well as the eight-wave mixing propagating along the same direction can be evoked by adjusting laser beams because these multi-wave mixing signals are induced by atomic coherence between common levels.

研究发现，通过调节激光束方向，沿同一方向出射的八波混频、双缀饰四波混频和单缀饰六波混频信号因共用能级的原子相干产生而出现竞争现象，通过控制缀饰场减弱四波混频和六波混频信号强度，可以达到增强八波混频信号的目的。

Chapter one is Mozart and opera creation. Chapter two is "The Marriage of Figaro" aria in the analysis of four.

第一章，莫扎特及其歌剧创作；第二章，《费加罗的婚礼》中四首咏叹调的分析；第三章，《费加罗的婚礼》中四首咏叹调的教学。。。

Connected with four intercepting devices, e .g. coils target, sky-screens and light-screens, it was able to measure the flying bullet in any pairs of them. The final velocity was directly displayed o n the panel. Connected with four sky-screens,it can measure the position where the flying bullet touches on the target.

配接线圈靶、天幕靶和光幕靶等区截装置，四个通道两两任意配对即可实现对飞行弹丸速度的测试，速度值可直接在仪器面板上显示，如果配接四个天幕靶，可实现弹丸着靶位置的测试。

Compared with the first and second quartile, the osteoporosis prevalence and risk were significantly increased in the women of the third and fourth quartile, and the fourth quartile had a significant higher prevalence and risk than the third quartile, especially in spine.

与一分位数和三分位数比较，四分位数的妇女骨质疏松症患病率和患病风险显著增加；与三分位数比较，处于四分位数的妇女骨质疏松症患病率和患病风险也显著增加，特别是在腰椎。

The age- and sex-adjusted hazard ratios for diabetes were 1.30, 1.63, and 2.83 for the second, third, and fourth quartiles of serum uric acid, in comparison with the first quartile.

研究人员报道：在年龄和性别做了相应调整后与第一次血清尿酸四分位数相比较，第二次糖尿病的危害比为1.30，第三次为1.63，第四次为2.83，。

Type 1; ordinary type; 2,(take a long time to work and television-type); III,(white-collar, no serious training-type activities) IV, serious; type (68 yuan is not Baoyou Fei), 2 (88 yuan is not Baoyou Fei), 3 (128 million), IV (288 yuan), 5 Diego Jiaoxin 100: Zishen with water, drop imaginary fire, Shugan Mingmu, and other functions, can control high-pressure, dizziness, tinnitus, insomnia, poor disease Flaccidity Foot Reflexology Diego, used his left hand and heart massage Youzu heart, heart with his right hand left foot massage heart of the 100 "on the Zuxin Fitness for "believing that it could" down with hot, strong physical body."

说明；二型、；三型、（白领、严重不活动锻炼型）四型、严重型；一型（68元不包邮费）、二型（88元不包邮费）、三型（128元）、四型（288元）、5型蹬踏脚心100次：具有滋肾水、降虚火、舒肝明目等功能，可防治高压、眩晕、耳鸣、失眠、足部痿弱等病症足底按摩蹬踏、常用左手心按摩右足心、用右手心按摩左足心各100次"足心上的健身术"，认为其可"引热下行，壮体强身"。

Supporting type is suggested to be developed into 3-prop to improve adaptability besides 2-prop and 4-prop. The difference of caving difficulty degree of coal seam is the base of caving coal method at high, medium and low position. Caving with small step and open caving flashboard used widely not only cause serious mixture of coal and rock but also hinder the improvement of top coal recovery. So we suggest caving with large step or closing caving door. Four-bar-mechanism of hydraulic support restricts development of new style caving powered support. Stabilization framework of expansion link and all-shield caving tail beam at high, medium and low position are introduced here.

支架支护型式，除了两柱、四柱以外，建议开发三柱支架以改善适应性；煤层冒放性的差异，是高位、中位和低位放煤方法存在和使用的依据；目前广泛采用的小步距放煤和开放式放煤插板不仅造成严重混矸漏矸，也妨碍顶煤回收率的进一步提高，建议采用大步距放煤和可关闭放煤口；液压支架四连杆稳定机构，制约了新型放顶煤液压支架的开发，介绍了液压支架伸缩杆稳定机构及全掩护拖移高位、中位和低位放煤尾梁。

This article discusses four factors of inditing exordium of Tolstoy s works: a the focusing point of implying the main line of a novel; b the entering point of accepting the historical background; c the flashing point of exposing the author s inclination ; d starting point of identifying the artistic style.

本篇着重研究了托尔斯泰开端创作的四个方面：一、隐示作品主线的聚焦点；二、接纳历史背景的切入口；三、透露作者倾向的闪光点；四、确定艺术风格的起程点。

It was wholly in the lower ice, but close against the upper, and was flattish, or perhaps slightly lenticular, with a rounded edge, a quarter of an inch deep by four inches in diameter; and I was surprised to find that directly under the bubble the ice was melted with great regularity in the form of a saucer reversed, to the height of five eighths of an inch in the middle, leaving a thin partition there between the water and the bubble, hardly an eighth of an inch thick; and in many places the small bubbles in this partition had burst out downward,and probably there was no ice at all under the largest bubbles,which were a foot in diameter.

在气泡之下和周围已经结了一层新的冰，所以气泡是在两片冰的中间；它全部是在下层中间的，却又贴近上层，扁平的，也许有点像扁豆形，圆边，深四分之一英寸，直径四英寸；我惊奇地发现，就在气泡的下面，冰溶化得很有规则，像一只倒置的茶托，在中央八分之五英寸的高度，水和气泡之间有着一个薄薄的分界线，薄得还不到一英寸的八分之一，在许多地方，这分界线中的小气泡向下爆裂，也许在最大的直径一英尺的气泡底下完全是没有冰的。

Four brothers from four states drove to Flatwoods, KY and spent the evening with these saints, their family and some other seeking brothers.

当晚，从四个州来的四个弟兄访问了平木市他们的家人和一些其他寻求的弟兄们。

Breath, muscle contraction of the buttocks; arch body, as far as possible to hold his head, right leg straight towards the ceiling (peg-leg knee in order to avoid muscle tension).

呼气，收缩臀部肌肉；拱起身体，尽量抬起头来，右腿伸直朝向天花板（膝微屈，以避免肌肉紧张）。

The cost of moving grain food products was unchanged from May, but year over year are up 8%.

粮食产品的运输费用与5月份相比没有变化，但却比去年同期高8％。