CN102842303A - Microporous-fiber composite sound absorbing board - Google Patents

Abstract

The invention provides a microporous fiber composite sound-absorbing board, which belongs to the field of instruments for absorbing noise by using the principle of resonance. The sound-absorbing board has good low-frequency sound-absorbing effect, and its sound-absorbing coefficient is greater than 0.5 at 125 Hz; it has a wider absorption frequency band than the aluminum fiber sound-absorbing board. At 250Hz-1600Hz, the sound absorption coefficient is not less than 0.4; the composite sound-absorbing panel is composed of micro-perforated panels and aluminum fiber panels, and adopts a double-resonance coupling structure, and the micro-perforated panels and aluminum fiber panels are connected by a keel to form a first The resonant cavity, the aluminum fiber board and the wall are connected by a dragon skeleton to form a second resonant cavity, the micro-perforated board and the aluminum fiber board are coupled through formant to improve the low-frequency sound absorption effect and expand the sound absorption frequency band. The composite sound-absorbing board of the present invention has an all-aluminum structure, has good recycling and reuse characteristics, and does not have problems such as aging and falling off; the sound-absorbing board also has good heat conduction characteristics, which is convenient for equipment to dissipate heat.

Description

A microporous fiber composite sound-absorbing panel

technical field

The invention belongs to the field of instruments for absorbing noise by using the principle of resonance, and in particular relates to a microporous fiber composite sound-absorbing board. the

Background technique

With the development of urbanization and the enhancement of residents' awareness of environmental protection, the noise problem of substations has gradually become a problem that the power grid operation department needs to face up to. At present, whether it is an urban substation or a rural substation, with the increasing shortage of land resources, the surrounding buildings and population density of the substation are gradually increasing, which also objectively causes the noise of the substation to become a hot spot for some urban residents to complain to the environmental protection department. The resulting petitions and mass incidents are increasing day by day. In the "Macro Environmental Strategy of the State Council" that has been issued, substations in the power industry have been clearly listed as the focus of noise control. the

At present, the noise sources of my country's substation (converter station) are mainly transformers, reactors, filters and fan cooling equipment. Among them, fan noise is mainly medium and high frequency noise, which can be effectively controlled by using traditional noise reduction materials and measures such as rock wool. However, the noise generated by transformers, high voltage reactors and filters is dominated by medium and low frequency electromagnetic noise in the octave range of 125-500Hz. According to previous research and treatment experience, this kind of low- and medium-frequency noise has a large wavelength, slows attenuation with distance, and has strong penetrating power to ordinary residential buildings. It will be difficult to achieve the newly promulgated GB12348- Low-frequency noise emission limits in the 2008 standard. Even if better noise reduction materials and measures are generally used at present, the impact of noise at home for residents far from the substation is still difficult to reach the newly promulgated national standard limit. Some data show that after the promotion of UHV power transmission and transformation technology, this exceeding standard will become more obvious. According to Chinese law, if the noise at the factory boundary exceeds the national noise emission standards and interferes with the normal life, work and study of others outside the factory boundary, the enterprise must pay the penalty for excessive noise pollution and compensate residents for their losses. Therefore, in order to avoid economic losses to enterprises and noise disturbance to residents, it is necessary to use new sound-absorbing materials or new sound-absorbing structures for noise control. the

All materials with strong sound absorption and noise reduction performance can be classified as sound-absorbing materials. In principle, the sound absorption coefficient should be greater than 02. Porous materials have been widely used as effective sound-absorbing materials for noise reduction, for example, materials like fiberglass panels and micro-perforated panels have been used to absorb airborne noise. the

According to the investigation of the substation's own service characteristics, the sound-absorbing materials required for substation noise control should have the following characteristics:

Has a certain mechanical strength;

It has excellent sound absorption effect for low and medium frequencies (mainly at 125-500Hz);

Not affected by the climate environment, the sound absorption coefficient will not decrease due to humidity in high humidity areas;

The heat transfer effect is good, which is conducive to the heat dissipation of the equipment;

Long service life, not easy to aging failure;

Safe and environmentally friendly, easy to recycle;

Small weight, easy to install and arrange;

Comprehensive use cost is low. the

Traditional sound-absorbing materials generally include glass wool, slag wool and rock wool. This kind of material has good medium and high frequency sound absorption performance, and has the characteristics of light weight, non-combustibility, non-corrosion, non-aging, low price, etc., thus replacing natural fiber sound-absorbing materials, and has been widely used in acoustic engineering. The main disadvantage of this type of material is the pollution of its dust to the environment. the

For example, rock wool/glass wool sound-absorbing materials have no strength, are easy to be damp, and basically do not absorb sound after being damp. It is easy to age and pollute the environment. Under certain service conditions, the rock wool dust will start to volatilize in 2-3 years, and the pollution will be serious in less than ten years on average. the

Rock wool fiber is a huge hazard to personnel. Workers exposed to glass wool, rock wool, and mineral wool may have X-ray chest changes, that is, changes in pneumoconiosis, and the lung function test FVC (forced expiratory volume) is lower than normal. The pathological examination of the lung biopsy of workers exposed to glass fiber showed that there were glass fiber dust cell foci in the lung tissue, mild hyperplasia of collagen, lung cancer, and lung abscess. the

In addition to the above environmental problems, mineral fiber sound-absorbing materials also have the following disadvantages:

Poor thermal conductivity: The thermal conductivity of rock wool glass wool is very low, and it is often used as thermal insulation material, which is not good for the heat dissipation of substation equipment;

No strength, need protection board: The strength of rock wool glass wool is very low, it cannot bear its own weight alone, and the outer layer needs to be covered with a protective layer and frame; 

Low sound absorption coefficient of medium and low frequency: For low frequency noise, especially frequency noise below 500Hz, its sound absorption coefficient is generally below 0.3, and the efficiency is low;

Susceptible to environmental influences: The sound absorption coefficient of rock wool glass wool sound-absorbing materials for high-frequency noise drops greatly after being damp, or even has no sound-absorbing effect at all. Because the outer plate of the protective layer needs a large number of holes to ensure the sound waves are transmitted, Therefore, it is impossible to completely seal the rock wool glass wool, that is, the problem of moisture cannot be well solved. the

At present, traditional sound-absorbing materials are widely used in China for sound-absorbing treatment, such as rock wool and glass wool, which account for more than 90% of all sound-absorbing materials in actual use. the

In addition to traditional sound-absorbing materials, some new sound-absorbing materials, such as foam metal and sprayed fibers, are also used in some key projects or projects with specific requirements for noise control. Foam metal sound-absorbing materials are expensive, which is not conducive to large-scale promotion; although sprayed fibers have good low-frequency sound-absorbing performance, their high price and poor thermal conductivity are also not conducive to serving in the field of power transmission and transformation. the

Metal fiber board has the characteristics of excellent heat transfer, light weight, and can be adjusted for low-frequency noise absorption through process adjustment, and the process is relatively simple, and the overall production cost is low. It is widely used in traffic noise reduction abroad. At present, metal fiber sound absorption is gradually valued in China. The development of materials, but the sound absorption effect for the low-frequency noise of the substation fundamental frequency 125Hz-500Hz is still insufficient. By adjusting the process parameters such as surface density, rolling gap, fiber diameter and other influencing conditions, the absorption peak can be effectively moved to the middle and low frequencies, but At this time, the absorption frequency band is narrow, and generally the absorption trough appears around 1000-1200Hz, so it needs to be adjusted through the structural form. the

In terms of sound-absorbing structures, China currently has a good foundation in theoretical research. Based on the theory of micro-perforated sound-absorbing structures published by Academician Ma Dayou, a number of advanced-level micro-perforated sound-absorbing structures have been developed. And on this basis, follow-up development and optimization. Various types of perforated plates are the most common resonant sound-absorbing structure. The micro-perforated structure uses the principle of Helmholtz resonators to reduce the noise by consuming the sound energy of the sound wave through resonance with the sound wave. Many factors such as the pore size, distribution mode, and arrangement density of the micro-perforated structure can affect the sound absorption effect of the structure. The combination of a single-layer micro-perforated sound-absorbing panel and a back cavity still cannot achieve a good low-frequency sound-absorbing effect. the

Application No. 201010191493.3, an invention patent titled "A Microporous Fiber Perforated Plate and Its Preparation Method", its technical solution provides a microporous fiber perforated plate and its preparation method, and the examples obtained The effect is at 125Hz, and the sound absorption coefficient is below 0.1, which cannot meet the requirements of low-frequency sound absorption. the

Contents of the invention

The purpose of the present invention is to provide a microporous fiber composite sound-absorbing panel. The composite sound-absorbing panel is a double-resonance coupling structure. The coupling between the micro-perforated panel and the aluminum fiber panel can improve the low-frequency sound-absorbing effect and expand the sound-absorbing frequency band. Purpose. The microporous fiber composite sound-absorbing panel has good low-frequency sound-absorbing effect, and its sound absorption coefficient is greater than 0.5 at 125 Hz; it has a wider absorption frequency band than aluminum fiber sound-absorbing panels, and its sound absorption coefficient is not less than 250 Hz-1600 Hz. 0.4; the sound-absorbing board is an all-aluminum structure, which is beneficial to recycling and environmental protection, has good recycling characteristics, and does not have problems such as aging and falling off; in addition, the sound-absorbing board also has good thermal conductivity, which is convenient for equipment Heat dissipation. the

For realizing the object of the present invention, the technical scheme that the present invention adopts is as follows:

A microporous fiber composite sound-absorbing board, the sound-absorbing board includes a micro-perforated board and an aluminum fiber board; the improvement is that the composite sound-absorbing board is a double resonance coupling structure, and the gap between the micro-perforated board and the aluminum fiber board is The first resonant cavity is formed through the keel connection, and the second resonant cavity is formed between the aluminum fiber board and the wall through the keel connection; the micro-perforated plate is an aluminum plate. the

Another preferred technical solution of the present invention is: the distance between the micro-perforated plate and the aluminum fiber plate is 20-80mm. the

Another preferred technical solution of the present invention is: the distance between the aluminum fiber board and the wall is 20-180 mm. the

Another preferred technical solution of the present invention is: the thickness of the micro-perforated plate is 0.5-1 mm, the hole diameter is 0.5-1.5 mm, and the hole spacing is 2-20 mm. the

Another preferred technical solution of the present invention is: the surface density of the aluminum fiberboard is 300-800g/m ² , and the fiber diameter is 70-150μm.

Another preferred technical solution of the present invention is: the aluminum fiber board sequentially comprises four layers of aluminum expanded mesh, aluminum fiber, aluminum foil and aluminum expanded mesh along the normal direction of the board surface. the

Owing to adopting above-mentioned technical scheme, beneficial effect of the present invention comprises:

1) Improve low-frequency sound absorption coefficient

The structure of the sound-absorbing panel is provided with a first resonant cavity and a second resonant cavity, the two resonant cavities and the thickness of the micro-perforated plate and the aluminum fiber plate form a double-resonant system, and its sound absorption coefficient at 125Hz is at least 0.523, Significantly improved the low-frequency sound absorption coefficient;

2) Broaden the sound absorption frequency band

Since the sound-absorbing panel of the present invention is made of two kinds of resonant materials, micro-perforated plate and aluminum fiber board, the sound-absorbing panel structure of the composite sound-absorbing panel is a double-resonance coupling structure, so that the resonance frequency of its vibration system is 125Hz-1600Hz, and the minimum sound absorption The coefficient is 0.42;

3) It has the characteristics of recycling

The aluminum fiber board and micro-perforated board that make up the composite sound-absorbing board are all-aluminum structures, which have good recycling characteristics and do not have problems such as aging and falling off; 

4) Excellent heat dissipation performance

The aluminum alloy has excellent thermal conductivity, which facilitates the heat dissipation of the equipment. the

Description of drawings

The present invention will be further described below in conjunction with the accompanying drawings. the

Figure 1 is a schematic diagram of the structure of the microporous fiber composite sound-absorbing panel;

Fig. 2 is a schematic diagram of the aluminum fiberboard structure;

Figure 3 is a curve diagram of the sound absorption coefficient of the sound-absorbing panel 1#;

Figure 4 is a graph of the sound absorption coefficient of sound-absorbing panel 2#;

Figure 5 is a graph of the sound absorption coefficient of sound-absorbing panel 3#;

Figure 6 is a graph of the sound absorption coefficient of sound-absorbing panel 4#;

Reference signs:

1-micro-perforated plate, 2-aluminum fiberboard, 3-long skeleton, 4-aluminum fiber, 5-aluminum foil, 6-aluminum expanded mesh, 7-first resonance cavity, 8-second resonance cavity;

SAC - sound absorption coefficient. the

Detailed ways

Below in conjunction with example the present invention is described in detail. the

The microporous-fiber sound-absorbing panel is a double-resonance coupling structure, and the two resonant sound-absorbing materials achieve the purpose of improving the low-frequency sound-absorbing effect and expanding the sound-absorbing frequency band through the coupling of the resonance peaks. the

1) Prepare the standard micro-perforated board 1 and aluminum fiber board 2 by optimizing the process conditions, and then conduct acoustic performance tests on the micro-perforated board 1 and aluminum fiber board 2 respectively, and master the corresponding relationship between the process parameters and the sound absorption characteristics of the two sound-absorbing boards;

2) Then, on the basis of a large amount of measured data in the early stage, an acoustic model is established, and the parameters of the two are re-optimized through simulation to guide the determination of the parameters of the composite sound-absorbing panel. And through the actual measurement, the model is constantly corrected to achieve the purpose of improving the accuracy of the simulation. Finally, after a large number of actual measurements and simulated screening, the optimal process parameters are obtained, and the microporous fiber composite sound-absorbing panels are prepared. the

By combining micro-perforated panels with aluminum fiber sound-absorbing panels, through necessary process control and adjustment, it is possible to not only maintain the low-frequency sound absorption effect of the original aluminum fiber sound-absorbing panels, but also broaden the absorption frequency band to achieve a wider range Achieve a sound absorption coefficient of not less than 0.4. the

The composite sound-absorbing panel is composed of micro-perforated board 1 and aluminum fiber board 2. Its specific structure is: micro-perforated board 1 is a panel, and aluminum fiber board 2 is arranged thereafter. There is a gap between micro-perforated board 1 and aluminum fiber board 2 The first resonant cavity 7, the first resonant cavity 7 refers to the hollow part formed between the micro-perforated plate 1 and the aluminum fiber plate 2 with a certain plane spacing; the aluminum fiber plate 2 is arranged behind the backboard or directly installed on the wall through the keel 3 Above, a second resonant cavity 8 is formed. The second resonant cavity 8 refers to the hollow part with a certain plane distance formed between the aluminum fiber board 2 and the wall; the micro-perforated board 1 and the aluminum fiber board 2 are also connected by the keel 3 . Refer to schematic diagram 1 for the specific structure. the

The microporous fiberboard 1, the distance between the microperforated board 1 and the aluminum fiberboard 2 is 20-80mm, and the thickness of the back cavity between the aluminum fiberboard 2 and the wall or backboard is 20-180mm;

The micro-perforated plate 1 is made of pure aluminum plate, the plate thickness is 0.5-1mm, the hole diameter is 0.5-1.5mm, and the hole spacing is 2-20mm;

The aluminum fiber board 2 is a commercially available aluminum fiber sound-absorbing board, and its specific parameters can be adjusted. Its structure is composed of front and rear aluminum expanded mesh 6, aluminum fiber 4, and aluminum foil ⁵ . The diameter is 70-150 μm, and the fiber type is aluminum fiber prepared by melting pumping method. The structure of aluminum fiber board 2 is shown in schematic diagram 2;

The sound absorption coefficient curve of the microporous fiber composite sound-absorbing panel generally increases with the increase of the frequency, gradually decreases after reaching the peak, and rebounds and rises after decreasing to the trough. So between 125-1600Hz, the minimum sound absorption coefficient appears at 125Hz, and at 250-1600Hz, the minimum sound absorption coefficient appears at the trough. the

Example 1: Sound-absorbing panel 1#

Micro-perforated plate 1: Prepare the micro-perforated plate 1 with a commercially available 0.5 mm aluminum plate, in which the hole spacing is 2 mm and the hole diameter is 1.5 mm;

Manufacturer Name: Zhongzhou Aluminum Co., Ltd.

Factory Address: Koutou Industrial Zone, Xiaoguan Town, Gongyi City, Henan Province

Aluminum plate model: 1050 series aluminum plate

The aluminum plates in Embodiment 2, Embodiment 3 and Embodiment 4 are all purchased from the above-mentioned manufacturers. the

Aluminum fiber board 2: Customized aluminum fiber board ² with an area density of 300g/m2, in which the aluminum fiber is prepared by melting and pumping method, and the fiber diameter is 120μm;

Combination: Combine the micro-perforated board 1 and the aluminum fiber board 2, and connect them through the keel 3. The distance between the micro-perforated board and the aluminum fiber board is 20mm, and the distance between the aluminum fiber board 2 and the wall is 180mm; it is made into a sound-absorbing board 1#;

The sound absorption coefficient curve (red line) of the sound-absorbing board 1# is shown in Figure 3. The sound-absorption coefficient curve of the aluminum fiber sound-absorbing board (AL-fibre board) used as a comparative experiment in Figure 3 is represented by a black line, and the test uses aluminum fiber The distance between the sound-absorbing board and the wall is 180mm, which is the same as that of the composite sound-absorbing board. It can be seen in the figure that the sound absorption coefficient curve of the microporous fiber composite board (Composite board) does not appear as in the sound absorption coefficient curve of the aluminum fiber sound-absorbing board. The trough whose sound coefficient is lower than 0.4 has a sound absorption coefficient of 0.523 at 125Hz; the minimum sound absorption coefficient of 250-1600Hz is 0.42;

Example 2: Sound-absorbing board 2#

Micro-perforated plate 1: A commercially available 0.6mm aluminum plate is used to prepare a micro-perforated plate, in which the hole spacing is 10mm and the hole diameter is 1.0mm;

Aluminum fiber board 2: Customized aluminum fiber board 2 with an area density of 400g/ ^m2 , in which the aluminum fiber is prepared by melting and pumping method, and the fiber diameter is 70μm;

Combination: Combine the micro-perforated plate 1 and the aluminum fiber plate 2, and connect them through the keel 3. The distance between the micro-perforated plate 1 and the aluminum fiber plate 2 is 40mm for the first resonance cavity 7, and the second resonance between the aluminum fiber plate 2 and the wall The distance of cavity 8 is 160mm; it is made into sound-absorbing board 2#;

The sound absorption coefficient curve (red line) of the sound-absorbing panel 2# is shown in Figure 4, and the sound-absorption coefficient curve of the aluminum fiber sound-absorbing panel as a comparison in Figure 4 is represented by a black line, and the test is performed between the aluminum fiber sound-absorbing panel and the wall The distance between surfaces is 160mm, which is the same as that of the composite sound-absorbing panel. It can be seen in the figure that the sound absorption coefficient curve of the microporous fiber composite panel does not appear as in the trough where the sound absorption coefficient is lower than 0.4 in the sound absorption coefficient curve of the aluminum fiber sound-absorbing panel, and its 125Hz sound absorption The coefficient is 0.768; the minimum sound absorption coefficient of 250-1600Hz is 0.525;

Example 3: Sound-absorbing board 3#

Micro-perforated plate 1: A commercially available 0.8mm aluminum plate is used to prepare a micro-perforated plate, in which the hole spacing is 15mm and the hole diameter is 0.8mm;

Aluminum fiber board 2: Customized aluminum fiber board with an area density of 500g/ ^m2 , in which the aluminum fiber is prepared by melting and pumping method, and the fiber diameter is 90μm;

Combination: Combine the micro-perforated plate 1 and the aluminum fiber plate 2, and connect them through the keel 3. The distance between the micro-perforated plate 1 and the aluminum fiber plate 2 is 60mm for the first resonance cavity 7, and the second between the aluminum fiber plate 2 and the wall The distance of resonance cavity 8 is 120mm; it is made into sound-absorbing board 3#;

The sound absorption coefficient curve (red line) of sound-absorbing panel 3# is shown in Figure 5. The sound-absorption coefficient curve of the aluminum fiber sound-absorbing panel as a comparison in Figure 5 is represented by a black line. Composite sound-absorbing panels are at the same distance of 160mm. It can be seen in Figure 5 that the sound absorption coefficient curve of the microporous fiber composite panel does not appear as in the trough where the sound absorption coefficient is lower than 0.4 in the sound absorption coefficient curve of the aluminum fiber sound-absorbing panel, and its 125Hz sound absorption coefficient is 0.597 ;250-1600Hz minimum sound absorption coefficient is 0.564;

Example 4: Sound-absorbing board 4#

Micro-perforated plate 1: A commercially available 1.0mm aluminum plate is used to prepare a micro-perforated plate, in which the hole spacing is 20mm and the hole diameter is 0.5mm;

Aluminum fiber board 2: custom-made aluminum fiber board with an area density of 800g/ ^m2 , in which the aluminum fiber is prepared by melting and pumping method, and the fiber diameter is 150 μm;

Combination: Combine the micro-perforated plate 1 and the aluminum fiber plate 2, and connect them through the keel 3. The distance between the micro-perforated plate 1 and the aluminum fiber plate 2 is 80mm for the first resonance cavity 7, and the second resonance between the aluminum fiber plate 2 and the wall The distance of cavity 8 is 20mm; it is made into sound-absorbing board 4#;

The sound absorption coefficient curve (red line) of the sound-absorbing panel 4# is shown in Figure 6. The sound-absorption coefficient curve of the aluminum fiber sound-absorbing panel as a comparison in Figure 6 is represented by a black line. Composite sound-absorbing panels have the same distance of 120mm. It can be seen in Figure 6 that the sound absorption coefficient curve of the microporous fiber composite panel does not appear as in the trough where the sound absorption coefficient is lower than 0.4 in the sound absorption coefficient curve of the aluminum fiber sound-absorbing panel, and its 125Hz sound absorption coefficient is 0.757 ;250-1600Hz minimum sound absorption coefficient is 0.402;

The parameter comparison of each embodiment is shown in Table 1:

Table 1: Example parameter comparison

the Acoustic panel 1# Acoustic panel 2# Acoustic panel 3# Acoustic panel 4# Micro-perforated plate thickness (mm) 0.5 0.6 0.8 1 Micro-perforation aperture (mm) 1.5 1.0 0.8 0.5 Micro-perforation pitch (mm) 2 10 15 20 Interval cavity distance (mm) 20 40 60 80 Composite sound-absorbing panel back cavity distance (mm) 180 160 120 20

[0091] Surface density of aluminum fiberboard (g/m ² ) 300 400 500 800 Aluminum fiberboard back chamber distance (mm) 180 160 160 120 Aluminum fiber diameter (μm) 120 70 90 150 Types of Aluminum Fiber Melting pumping Melting pumping Melting pumping Melting pumping 125Hz sound absorption coefficient 0.523 0.768 0.597 0.757 250-1600Hz minimum sound absorption coefficient 0.42(872Hz) 0.525(576Hz) 0.564(568Hz) 0.402(1488)

The invention has been described herein in terms of specific exemplary embodiments. Appropriate substitutions or modifications will be apparent to those skilled in the art without departing from the scope of the present invention. The exemplary embodiments are illustrative only, and not limiting of the scope of the invention, which is defined by the appended claims. the

Claims (6)

1. microporous fibre sound-absorbing composite board, said acoustic board comprises microperforated panel (1) and aluminum fiberboard (2); It is characterized in that said sound-absorbing composite board is the double resonance coupled structure; Be connected to form first resonating cativty (7) through keel (3) between said microperforated panel (1) and the aluminum fiberboard (2), be connected to form second resonating cativty (8) through keel (3) between said aluminum fiberboard (2) and wall or the backboard; Said microperforated panel (1) is an aluminium sheet.

2. a kind of microporous fibre sound-absorbing composite board as claimed in claim 1 is characterized in that the interplanar distance between said microperforated panel (1) and the aluminum fiberboard (2) is 20-80mm.

3. a kind of microporous fibre sound-absorbing composite board as claimed in claim 1 is characterized in that the interplanar distance between said aluminum fiberboard (2) and wall or the backboard is 20-180mm.

4. a kind of microporous fibre sound-absorbing composite board as claimed in claim 1, the thickness of slab that it is characterized in that said microperforated panel (1) is 0.5-1mm, and the aperture is 0.5-1.5mm, and pitch of holes is 2-20mm.

5. a kind of microporous fibre sound-absorbing composite board as claimed in claim 1, the surface density that it is characterized in that said aluminum fiberboard (2) is 300-800g/m ², fibre diameter is 70-150 μ m.

6. a kind of microporous fibre sound-absorbing composite board as claimed in claim 1 is characterized in that said aluminum fiberboard (2) is made up of aluminium expanded sheets (6), aluminum fiber (4), aluminium foil (5) and aluminium expanded sheets (6) four layer materials along plate face normal direction successively.

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