加湿器英语文章

A control system is designed to control the dynamic behavior( the time response) of a plant subject to commands or disturbances. The designer should be fully aware, however, of the role of the steady equations and errors in the overall process, as well as their influence on the dynamic behavior of the plant.控制系统设计就是使装置在有指令信号或者干扰时有满意的行为（时域响应）。设计者必须清楚地知道整个过程的稳态方程和误差，以及他们对装置的动态性能的影响。An accuracy of a system is a measure of how well it follows commands. It is an important performance criterion; a guidance system that cannot place spacecraft on a suitable trajectory is obviously useless no matter how well-behaved its transient response.衡量系统的精度之一，就是其如何跟踪给定命令。这是一项重要的性能指标。一个导航系统如果不能将飞行器置于合适的轨迹，那么无论有多好的动态性能，都是没有用。Actual system are also subjected to undesirable inputs, such as noise in command inputs and disturbances arising from changes in the plant parameters or changes in the environment in which the plant is operating. Noise inputs that enter the system with the command input require filtering techniques to remove or suppress them without affecting the command input itself. We shall limit our discussion to disturbance inputs which enter the system at the plant rather than at the controller.实际系统总是容易受到不希望的输入干扰，例如， 命令输入中的噪声以及由于参数改变在被控对象中产生的干扰或者被控对象工作环境变化产生的干扰。随着命令输入进入系统的噪声输入需要滤波器进行驱除或者抑制并不对输入信号产生影响。我们将限于讨论通过被控对象进行系统的噪声而不讨论通过控制器进入系统的噪声。It is often difficult to minimize both components of the error simultaneously. Obviously, it is necessary to have some knowledge as to the nature of probable disturbance inputs. Both error terms of Eq.(2-2B-7) can be set equal to zero by introducing an integrator into the controller. This additional integrator increases the type of the system ( from 1 to 2, for example) , thus eliminating the velocity error, and by being introduced ahead of the point of entry of the disturbance into the system, eliminates the steady-state error resulting from a step in the disturbance input. This additional integrator must be accompanied by at least one zero if the system is to remain stable.通常同时将误差的两个部分最小化是困难的。很明显，具有适当的干扰输入特性的一些知识是很有必要的。方程2-2B-7的两个误差项都能通过在控制器中加入积分器而消除。这些附加的积分器增加了系统的型（例如，从1型系统变为2型系统），因此可以消除速度误差，并通过在系统扰动进入点之前引入积分环节，可以消除由输入信号中包含的阶跃扰动引起的稳态误差。如果要保持系统稳定该附加的积分器必须相应增加至少一个零点。

加湿器的英文：humidifier

词汇解析

humidifier

英[hjʊ'mɪdɪfaɪə]；美[hju'mɪdɪfaɪɚ]

n. 增湿器，加湿器

例：How often do I need to clean my humidifier?

我要隔多久需要清理我的加湿器？

例：Humidifier. With or without valve can be specified.

加湿器可指定带有阀门或没有阀门。

扩展资料

近义词

1、humid

英['hjuːmɪd]；美['hjumɪd]

adj. 潮湿的；湿润的；多湿气的

例：Visitors can expect hot and humid conditions.

游客们会遇到炎热潮湿的天气状况。

例：Outside, the sun beats mercilessly down in the humid air.

外面，太阳在潮湿的空气中无情地照射着。

2、cleaner

英['kliːnə]；美['klinɚ]

n. 清洁剂；清洁工；干洗店；干洗商；洗洁器

例：He was a window cleaner.

他是一名窗户清洁工。

例：Did you pick up my suit from the cleaner's?

你顺便从干洗店取我的西装了吗？

加湿器 Humidifier A humidifier is a household appliance that increases humidity (moisture) in a single room or in the entire home. There are point-of-use humidifiers, which are commonly used to humidify a single room, and whole-house or furnace humidifiers, which connect to a home's HVAC system to provide humidity to the entire house.Evaporative humidifiersThe most common humidifier, an "evaporative" or "wick humidifier", consists of just a few basic parts: a reservoir, wick and fan.ReservoirReservoirs are common to most humidifiers and come in different shapes and sizes. The reservoir is a containing tank of water filled prior to operation, and provides the water for the moisture output. Other types have a continuous feed from a water line.WickThe wick is a filter that absorbs water from the reservoir. Evaporation of water from the wick is dependent on relative humidity. A room with low humidity will have a higher evaporation rate compared to a room with high humidity. Therefore, this type of humidifier is self-regulating: As the humidity of the room increases, the water vapor output naturally decreases. These wicks regularly need cleaning and replacement — if this does not happen, the humidifier stops humidifying the area it is in and the water in the tank remains at the same level.FanThe fan is adjacent to the wick and blows air onto the wick, thus aiding in the evaporation of the water within the wick.[edit] Other types of humidifiersOther types of humidifiers include:Vaporizer (Steam Humidifier) (Warm Mist Humidifier) — Boils water, releasing steam and moisture into the air. A medicated inhalant can also be added to the steam vapor to help reduce coughs. Vaporizers are more healthful[1] than cool mist types of humidifiers because steam is sterile and free from minerals. Vaporizers use more electricity to boil the water. Impeller Humidifier (Cool Mist Humidifier) — A rotating disc flings water at a diffuser, which breaks the water into fine droplets that float into the air. Ultrasonic Humidifier — A metal diaphragm vibrating at an ultrasonic frequency creates water droplets that exit the humidifier in the form of a cool fog silently. Ultrasonic Humidifiers should be cleaned regularly to avoid bacterial contamination which may be projected into the air. Impeller and ultrasonic humidifiers do not selectively put water in the air, they also add any suspended material in the water to the air such as microorganisms and minerals. The amount of minerals and other materials can be greatly reduced by using distilled water, though no water is absolutely pure. Filters may also reduce the amount of material but the EPA warns, "the ability of these devices to remove minerals may vary widely."[2] Depending on the volume, this dust may have negative health effects. Wick humidifiers trap the mineral deposits in the wick.Forced-Air HumidifiersFor buildings with a forced-air furnace, a humidifier may be built right into the furnace. They can also protect wooden objects, antiques and other furnishings which may be sensitive to damage from overly dry air. In colder months, they may provide substantial energy savings, since as humidity increases, occupants feel warm at a lower temperature. These units are typically called bypass humidifiers (because they are connected between the heated and cold air return ducts, using the pressure difference between these ducts to cause some heated air to make a bypass through the humidifier and return to the furnace). The humidifier should usually be disabled during the summer months if air conditioning is used; air conditioners partially function by reducing indoor humidity. There are three basic styles:Drum style: A pipe brings water directly to a reservoir (a pan) attached to the furnace. The water level in the pan is controlled by a float valve, similar to a small toilet tank float. The wick is typically a foam pad mounted on a drum and attached to a small motor; hot air enters the drum at one end and is forced to leave through the sides of the drum. When the hygrostat calls for humidity, the motor is turned on causing the drum to rotate slowly through the pan of water and preventing the foam pad from drying out. Advantages include: Low cost Inexpensive maintenance (drum-style pads are cheap and readily available)[citation needed] Disadvantages include: Requirement for frequent (approximately monthly) inspections of cleanliness and pad condition Water evaporation even when humidification is not required (due to the pan of water which remains exposed to a high velocity air stream) Mold growth in the pan full of water (this problem is exacerbated by the large quantity of air, inevitably carrying mold spores, passing through the humidifier whether in use or not). For the latter reason especially, drum-style humidifiers should always be turned off at the water supply during summer (air conditioning) months, and should always be used with high quality furnace air filters (MERV ratings as high as possible to ensure small numbers of mold spores reaching the humidifier's pan) when the water supply is turned on.Disc Wheel Style: Very similar in design to the drum style humidifiers, this type of furnace humidifier replaces the foam drum with a number of plastic discs with small grooves on both sides. This allows for a very large evaporative surface area, without requiring a great deal of space. Unlike the drum style humidifiers, the disc wheel does not need replacing.[1] Advantages include: Very low maintenance (basin of humidifier should be cleaned out periodically, unless automatic flushing device is installed) No regular replacement of parts necessary Higher output due to large evaporative surface area Can be installed in hard water situations Maintains efficiency throughout lifespan Disadvantages include: Higher price Water evaporation even when humidification is not required (due to the pan of water which remains exposed to a high velocity air stream) Flow-Through Style (also known as "biscuit style" or many other, similar variant names): A pipe brings water directly to an electrically-controlled valve at the top of the humidifier. Air passes through an aluminum "biscuit" (often called a pad; using the term "biscuit" to emphasize the solid rather than foamy form) which is similar to a piece of extremely coarse steel wool. The biscuit has a coating of a matte ceramic, resulting in an extremely large surface area within a small space. When the hygrostat calls for humidity, the valve is opened and causes a spray of water onto the biscuit. Hot air is passed through the biscuit, causing the water to evaporate from the pad and be carried into the building. Advantages include: Reduced maintenance (new biscuit only when clogged with dust or mineral deposits, typically once per year) Lack of a pan of potentially stagnant water to serve as a breeding ground for mold as with a drum-style humidifier No incidental humidification caused by a constantly-replenished pan of water in a high velocity air stream Reduced requirement for expensive air filters Uses no electricity Disadvantages include: A somewhat higher purchase price Manufacturer and model-specific replacement biscuits versus the relatively generic drum-style pads A portion of the water supplied to the unit is not evaporated. This can generate a considerable amount of waste water, and does require connection to a drain. Disadvantages and risksThe use of a humidifier can allow the reproduction of dust mites or the growth of harmful mold, which can be especially harmful for children and the elderly. The relative humidity should be kept between 30% and 50%. [3]. Can also cause Hypersensitivity pneumonitis (humidifier lung) [4]Some humidifiers now use Microban technology to reduce mold and bacteria growth within the humidifier.The EPA provides detailed information of the risks as well as recommended maintenance procedures.[5]Some humidifiers have no silent operation.HumidistatA controller that measures and controls relative humidity. A humidistat may be used to control either humidifying or dehumidifying equipment by the regulation of electric or pneumatic switches, valves, or dampers.An electronic humidistat includes a sensing element and a relay amplifier. The sensing element consists of alternate metal conductors on a small flat plate. An increase or decrease of the relative humidity causes a decrease or increase in the electrical resistance between the two sets of conductors and the change in resistance is measured by the relay amplifier.See alsoDehumidifier HVAC Hygrometer for measuring humidity Humidifier fever Humidistat Ioniser Misting fan

People from almost all cultures throughout history have been making objects from wood. Some of the first wooden objects included weapons and tools. Early cultures also learned to make boats, buildings and tools. Early cultures also learned to make boats, buildings and furniture for home from this material. However, it is not always easy to say which wooden objects existed during a historical period tecause they often did not last as long as objects made from clay or metal. 有史以来的各个文化，人们用木头制作物品。最初的木头制品有武器和工具。早期文化（人们）还学会用这种材料造船，建筑物和家俱。然而，不好说木制品在历史长河中存在的时期，因为它们不像陶制品或金属制品一样能保存很长时间。Experts say most current woodworking tools were developed by the beginning of the Bronze Age, about five thousand years ago. These tools include the saw, ax, chisel and drill which are used to cut and shape wood in different ways. Also, there are many methods of wood-working and each culture has its own tradition. Artistic wood creations include architectural decoration on uildings, furniture for home or even carved animals. For example, in Thailand, richly-detailed carvings(雕刻) from teak and other hard wood are an important part of ancient palaces and religious buildings. 专家推断现存的木工刀具出现在约5000年前的铜器时代早期。这些锯，斧，凿，钻等工具用不同方式切削木头。而且，还有很多方式的木工刀具，每个文化都有自己的特色。木制艺术制品包括建设上的装饰，家俱或动物雕像。举个例子，在泰国，丰富精致的柚木或其它坚木的雕刻品是古代宫殿和宗教建筑的重要组成部分。Woodcarvers were a very important group of artists. A person needed many years of training with experts to be a woodcarver. Wood carvings often include plant forms such as the lotus flower as well as figures taken from Hindu and Buddhist religious stories. 木雕是艺术的重要组成部分。人们要经过专家的多年培训才能成为木雕师。木雕通常包括植物形态，如采用印度和佛教故事描述的莲花。The carvings are very detailed and must be carefully planned. Usually, a carver draws out the patterns and forms on paper. Then the artist cuts holes along the outline of the design. This paper is placed on the piece of wood then covered with chalk dust. The white chalk dust goes through the holes in the paper and marks the wood, so the carver has a visual guide to begin cutting. Finished woodcarvings are often painted, sometimes with gold to reflect the surrounding light. These expertly made golden carvings give an airy lightness to Thai buildings. 雕刻注重细节和慎重布局。通常雕刻师在纸上描画出样式和外形。然后艺术家从沿着设计的轮廓打孔。把这张纸覆盖在一块木头上，把白灰撒上去。白灰通过纸上的孔洞在木头下留下标记。这样雕刻师就可以看着指示开始切削。（制作）成品木雕经常是苦活，有时要加上金片来反射周围光线。通过这些专业加工，金晃晃的雕刻品给泰国建筑空灵的光彩。 Unit 2The stability of a continuous or discrete-time system is determined by its response to input or disturbance. Intuitively, a stable system is one that remains at rest (or in equilibrium) unless excited by an external source and returns to rest if all excitations are removed. The output will pass through a transient phase and settle down to a steady-state response that will be of the same form as, or bounded by, the input. If we apply the same input to an unstable system, the output will never settle down to a steady-state phase; it will increase in an unbounded manner, usually exponentially or with oscillation of increasing amplitude. 连续或离散系统的稳定性由其对输入或者干扰的响应决定。直观地说，如果一个系统是稳定的，则其停留在稳态（或者平衡点），除非是受到外部激励，且当外部激励去除后，输出又回到稳态点。输出经过瞬态阶段后将回到与输入有相同形式的稳态或者是在输入的附近。如果我们将同样的输入作用于不稳定的系统，其输出将不会回到稳态，而是以无界的方式增长，通常其幅值是指数增长或者振荡增长。Stability can be precisely defined in terms of the impulse response of a continuous system, Kronrcker delta response of a discrete-time system, as follows: A continuous (discrete-time) system is stable if its impulse response (Kronecker response ) approaches zero as time approaches infinity.系统的稳定性可以用连续系统的脉冲响应 或者离散系统的Kronrcker Δ 响应 来定义：一个连续（离散）系统是稳定的，如果其脉冲响应 （Kronrcker Δ 响应 ）当时间趋于无穷大时趋于零。An acceptable system must at minimum satisfy the three basic criteria of stability, accuracy, and a satisfactory transient response. These three criteria are implied in the statement that an acceptable system must have a satisfactory time response to specified inputs and disturbances. So although we work in the Laplace and frequency domains for convenience, we must be able to relate these two domains, at least qualitatively, to the time domain.一个可接受的系统必须至少满足：稳定性、精度和满意的瞬态响应这三个指标。在陈述：“一个可接受的系统对指定输入和扰动必须有满意的时域响应”已经包含了这三个指标的含义。因此尽管我们为了方便工作在拉氏域或者频率域，我们必须与时间域（至少是定性的）相联系。With the transfer function in the form of Eq.(2-2A-1), the order of the system in defined as the order of the characteristic function D(s), the highest power of s appearing in D(s) establishes the order of the system.在传递函数所在的方程(2-2A-1)中，系统的阶次定义为特征函数D(s)的阶次，因此D(s)的最高次幂决定了系统的阶次。The first term is the forced solution, due to the input, and the second the transient solution, due to the system pole. Fig.2-2A-2 shows this transient as well as c(t). The transient is seen to be a decaying exponential, and the commonly used measured of the speed of decay is the time constant: The time constant is the time in seconds for the decaying exponential transient to be reduced to e-1=0.368 of its initial value. Since when t=T, it is seen that the time constant for a simple lag is T seconds. This is, in fact, the reason a simple lag transfer function is often written in this form. The coefficient of s then immediately indicates the speed of decay, and it takes 4T seconds for the transient to decay to 1.8% of its initial value.第一项为强迫解，对应于输入；第二项为瞬态解，对应于系统的极点。 在图2-2A-2中，该瞬态解为c(t)。瞬态解看上去为指数衰减的，且通常用于衡量衰减速度的是时间常数：即指数衰减的瞬态解衰减至其初始值的36.8%所需的时间（秒数）。因为，当t=T, ，对于一阶惯性环节，时间常数是T秒。这也是为什么一阶惯性环节要写成这个形式。S的系数立即给出了衰减的速度。而且，当时间为4T时， 瞬态解衰减至初始值的1.8%。B：Steady StateA control system is designed to control the dynamic behavior( the time response) of a plant subject to commands or disturbances. The designer should be fully aware, however, of the role of the steady equations and errors in the overall process, as well as their influence on the dynamic behavior of the plant.控制系统设计就是使装置在有指令信号或者干扰时有满意的行为（时域响应）。设计者必须清楚地知道整个过程的稳态方程和误差，以及他们对装置的动态性能的影响。An accuracy of a system is a measure of how well it follows commands. It is an important performance criterion; a guidance system that cannot place spacecraft on a suitable trajectory is obviously useless no matter how well-behaved its transient response.衡量系统的精度之一，就是其如何跟踪给定命令。这是一项重要的性能指标。一个导航系统如果不能将飞行器置于合适的轨迹，那么无论有多好的动态性能，都是没有用。Actual system are also subjected to undesirable inputs, such as noise in command inputs and disturbances arising from changes in the plant parameters or changes in the environment in which the plant is operating. Noise inputs that enter the system with the command input require filtering techniques to remove or suppress them without affecting the command input itself. We shall limit our discussion to disturbance inputs which enter the system at the plant rather than at the controller.实际系统总是容易受到不希望的输入干扰，例如， 命令输入中的噪声以及由于参数改变在被控对象中产生的干扰或者被控对象工作环境变化产生的干扰。随着命令输入进入系统的噪声输入需要滤波器进行驱除或者抑制并不对输入信号产生影响。我们将限于讨论通过被控对象进行系统的噪声而不讨论通过控制器进入系统的噪声。It is often difficult to minimize both components of the error simultaneously. Obviously, it is necessary to have some knowledge as to the nature of probable disturbance inputs. Both error terms of Eq.(2-2B-7) can be set equal to zero by introducing an integrator into the controller. This additional integrator increases the type of the system ( from 1 to 2, for example) , thus eliminating the velocity error, and by being introduced ahead of the point of entry of the disturbance into the system, eliminates the steady-state error resulting from a step in the disturbance input. This additional integrator must be accompanied by at least one zero if the system is to remain stable.通常同时将误差的两个部分最小化是困难的。很明显，具有适当的干扰输入特性的一些知识是很有必要的。方程2-2B-7的两个误差项都能通过在控制器中加入积分器而消除。这些附加的积分器增加了系统的型（例如，从1型系统变为2型系统），因此可以消除速度误差，并通过在系统扰动进入点之前引入积分环节，可以消除由输入信号中包含的阶跃扰动引起的稳态误差。如果要保持系统稳定该附加的积分器必须相应增加至少一个零点。

Humidifier 普通加湿器Purifying Humidifier 净化加湿器