查询词典 focal length

System.out.println("a.length="+ a.length); System.out.println("b.length ="+ b.length);// The handles inside the array are // automatically initialized to null: for(int i = 0; i nbsp;b.length; i++) System.out.println; System.out.println("c.length ="+ c.length); System.out.println("d.length ="+ d.length); a = d; System.out.println("a.length ="+ a.length);// Java 1.1 initialization syntax: a = new Weeble { new Weeble, new Weeble }; System.out.println("a.length ="+ a.length);// Arrays of primitives: int e;// Null handle int f = new int[5]; int g = new int[4]; for(int i = 0; i nbsp;g.length; i++) g = i*i; int h ={ 11, 47, 93 };// Compile error: variable e not initialized://!

句柄。此时，编译器会禁止我们对这个句柄作任何实际操作，除非已正确地初始化了它。数组b被初始化成指向由Weeble句柄构成的一个数组，但那个数组里实际并未放置任何Weeble对象。然而，我们仍然可以查询那个数组的大小，因为b指向的是一个合法对象。这也为我们带来了一个难题：不可知道那个数组里实际包含了多少个元素，因为length只告诉我们可将多少元素置入那个数组。换言之，我们只知道数组对象的大小或容量，不知其实际容纳了多少个元素。尽管如此，由于数组对象在创建之初会自动初始化成null，所以可检查它是否为null，判断一个特定的数组&空位&是否容纳一个对象。类似地，由基本数据类型构成的数组会自动初始化成零、null或者false。

A dioptre is 1 divided by the focal length of the lens in centimetres. So a 1-dioptre lens has a focal length of 1m; a 2-dioptre lens has a focal length of 50cm; a 5D lens has a focal length of 20cm.

一屈光度是1除以该镜头焦距在厘米，所以一屈光度镜头焦距一米； 2屈光度镜头焦距50厘米； 1日5日镜头焦距二○厘米）。

It's M2 factor is approaching the ideal value 1 and the beam intensity profile remains Gauss Profile. Laser beam with good propagation and focus characters. The beam can propagate a long way and can be focused with lens with long focal distance. The focal beam waist radius is 134μm, the focal distanced of the focus lens is 300mm. It's focal depth is about 5mm and the focal shift is about 1mm in the range of processing (3m).

结果表明，Slab CO2激光器具有高光束质量，其M2因子非常接近1的理想值；激光束具有良好的传输和聚焦性能，可以长距离传输；使用焦距为300mm的聚焦镜聚焦，聚焦光斑的束腰半径约为134μm，光束横截面能量分布接近理想的高斯分布，焦深约为5mm，在加工范围内(3m)，激光束的焦点漂移量大约为1mm。

So the technique of uncooled microbolometer infrared imaging has become one of the main points from now on. In the paper uncooled microbolometer infrared imaging system is studied from focal plane character, image dealing and application. The details are in the following: On uncooled microbolometer infrared focal plane aspect: first, the work principle of microbolometer, manufacturing technology of microbolometer infrared focal plane, temperature balance equation of microbolometer detector are analyzed. The performance of microbolometer detector is predicted by model. Second, the infrared focal plane is the core of infrared system, whose quality can determine the performance of the system. It is the precondition that the high quality of every detective unit maintains the qualification of the focal plane. The even degree of detective units has great influence on imaging characters if the other characters of detective units are normal.

本文以非致冷微测辐射热计红外成像系统为对象，从焦平面特性、图像处理和红外系统应用方面展开分析、研究，具体内容如下；在微测辐射热计红外焦平面方面，首先分析了微测辐射热计的工作原理、微测辐射热计红外焦平面的工艺制作、微测辐射热计探测单元的温度平衡方程，根据有关参数对其特性进行建模预测；其次，红外焦平面是红外系统的核心，它的质量的好坏直接决定系统性能，因此保证其各探测单元的高性能是维护焦平面品质的前提，在探测单元其它特性正常的情况下，各探测单元之间特性的均匀程度对系统成像性能有极大影响，为此本文提出自适应滤波多项式焦平面非均匀性校正算法从软件角度解决焦平面的固有的噪声问题。

According to the obtained characteristics of focal points and principal planes, using the expressions of focal point, focal plane, focal length, principal point, and principal plane of geodesic lenses, the geometry graphic imaging formation principles of geodesic lenses are developed to get the object-image-relation of geodesic lenses .

利用短程透镜焦点、焦平面、焦距、主点、主平面等的表达式，根据短程透镜在大口径范围内理想聚焦，主平面为以焦点为圆心、以焦距为半径、在原点相切的两个圆弧等性质，推导出了短程透镜物像关系的作图法求取原则。

The laser beam emitted by the laser is expanded to the cutting width required by the tipping paper via the laser beam expanding system, the expanded laser beam passes through the cylindrical surface focusing mirror and 4 focuses on the focal plane form a focal line and the tipping paper is cut off by the focal line on the focal plane.

由激光器发出的激光束经激光扩束系统将激光束扩大至水松纸所需的切割宽度，经扩束后的激光束通过柱面聚焦镜，在焦平面4聚焦形成一条聚焦线，水松纸在焦平面上被此条激光聚焦线割断。

The results indicate that multiple reflections are favorable to the increase of depth. When the focal position is above the surface, the absorptive intensity on the front decreases, so the cutting depth decreases. When the focal position is below the surface, the position on the front with the maximum power intensity is downward. The intensity distribution is toward the deeper position, the cutting depth increases. But if the negative focal distance is extremely big, the intensity of the deeper position attenuates sharply with the increase of focal radius and light distances, so the depth deceases.

正离焦切割时，前沿吸收的总激光功率密度减小，切割深度减小；负离焦切割时，最大激光功率密度值的位置下移，使得前沿功率密度分布朝着深部推进，切割深度增加，若负离焦量过大，表面光斑直径和光程增加，更深位置的功率密度减小，切割深度减小；随着激光功率增加、切割速度减小，则前沿弯曲程度减小，被激光直接照射的前沿部位增长，前沿吸收激光功率密度增加，切割深度增加。

Pass to count to Wisterch parameter , and the steel wire is different from the molding tool get in touch with the length, and settle the path the research taking the length work the stabber angle to get under differently pull to stir the term, mold core adoption of best severally why size, combine the best work stabber of research the Cape, and settle the path to take the length nextly steel wire is in the molding tool of have fever to measure, air inside dispel-heat calories, winding dispel-heat on the coil-canister , and its molding tool dispel-heat calories of, and cause the steel wire the temperature difference pass in and outing the molding tool to influence steel wire machine function, under the experiment inside pull to stir the term according to the same race different work stabber Cape half of adoption the Cape(7 degree,10 degree,12 degrees, the best mold Cape, experience mold Cape) settle the path to take the length(2-3 mm,3-4 mm,4-5 mms, theories length, experience length) to proceed to experiment, and get the conclusion, work stabber the Cape then is more big the steel wire get in touch with the length with

通过对Wisterch参数，钢丝与模具接触长度、定径带长度、工作锥角度的研究得到了在不同拉拨条件下模芯采用的最佳几何尺寸，并研究最佳工作锥角、定径带长度下钢丝在模具中的发热量、空气中散热量、卷筒上的散热量及其模具散热量的不同，导致钢丝进出模具的温度差别对钢丝机械性能的影响，在实验中根据同种拉拨条件下采用不同工作锥角半角、定径带长度进行试验，得出结论，工作锥角越大则钢丝与模具接触长度越短，钢丝变形越剧烈，在模具中发热量就越高，导致钢丝出模温度高，使钢丝强度、硬度升高，弯曲、扭转次数降低，并且降低模具使用寿命。在其它条件相同的情况下，定径带越长则钢丝与定径带简壁磨擦增大，使钢丝发热量加大，从而使钢丝强度、硬度略升高，弯曲扭转次数略降低但定径带的增大减小了钢丝变形产生的弹性后效使钢丝出模直径比较稳定。

The design of four-mirror anastigmat was analyzed, then a system with effective focal length of 1 200 mm and field of view of 0.8°×0.8° was designed , total length and f-number are 300 mm and F/6,respectively.The system has advantages of long focal length, relative short physical size and excellent ability in restraining stray lights.

分析了离轴四反的设计步骤，设计了一个焦距为1 200 mm，视场为0.8°×0.8°，相对孔径为F/6的光学系统，系统总长只有300 mm，并达到很好的光学性能，具有长焦距、小尺寸、良好的杂散光抑制能力等特点。

The results show that due to the effect of laser beam quality on focal beam waist radius,focal angle and focal length,laser beam quality decides the beam focusing ability and the processing capacity of laser system.

结果表明，光束质量对聚焦光束的焦斑、聚焦角和焦深的影响不仅体现了激光源的可聚焦性，而且也标志了激光源的可加工能力，这是聚焦系统和焦点位置在选择过程中应该考虑的重要因素。

Objective To study the effect of chitosan in the prevention of fibrous scar formation in the epidural space after laminectomy.

目的 观察选择性脊神经后根切除术椎板切除后硬膜外几种防瘢痕粘连物质的作用并探讨其机制。

On his way to the lift, he looked back to us or was it me his eyes pointing?

当他要进电梯时，他回头看我们（或者说是我，他的眼光？