Cet article traite de la découverte de lithopone phosphorescent sur des dessins à l'aquarelle, datés entre 1890 et 1905, de l'artiste Américain John La Farge et de l'histoire du lithopone dans l'industrie des pigments à la fin du 19e et au début du 20e siècle. Malgré de nombreuses qualités souhaitables pour une utilisation en tant que blanc dans les aquarelles et les peintures à l'huile, le développement du lithopone comme pigment pour artistes a été compliqué de par sa tendance à noircir lorsqu'il est exposé au soleil. Sa disponibilité et son usage par les artistes demeurent incertains parce que les catalogues des marchands de couleurs n'étaient généralement pas explicites à indiquer si les pigments blancs contenaient du lithopone. De plus, lors d'un examen visuel, le lithopone peut être confondu avec le blanc de plomb et sa phosphorescence de courte durée peut facilement être ignorée par l'observateur non averti. À ce jour, le lithopone phosphorescent a seulement été documenté sur une autre œuvre: une aquarelle de Van Gogh. En plus de l'histoire de la fabrication du lithopone, cet article décrit le mécanisme de sa phosphorescence et son identification à l'aide de la spectroscopie Raman et de la spectrofluorimétrie. En este artículo se discute el descubrimiento del litopón fosforescente en dibujos a la acuarela por el artista americano John La Farge, fechados de 1890 a 1905, y la historia del litopón en la industria de los pigmentos a finales del Siglo XIX y principios del Siglo XX. A pesar de tener muchas cualidades deseables para su uso en pintura para acuarela o pinturas al óleo blancas, el desarrollo del litopón como pigmento para artistas fue obstaculizado por su tendencia a oscurecerse con la luz solar. Su disponibilidad para los artistas y su adopción por ellos sigue siendo poco clara, ya que por lo general los catálogos comerciales de los coloristas no eran explícitos al describir si los pigmentos blancos contenían litopón. Además, el litopón se puede confundir con blanco de plomo durante el examen visual, y su fosforescencia de corta duración puede ser fácilmente pasada por alto por el observador desinformado. A la fecha, el litopón fosforescente ha sido documentado solamente en otra obra mas: una acuarela por Van Gogh. Además de la historia de la fabricación del litopón, el artículo detalla el mecanismo para su fosforescencia, y su identificación con la ayuda de espectroscopía de Raman, y de espectrofluorimetría. Este artigo discute a descoberta de litopônio fosforescente em desenhos de aquarela do artista americano John La Farge datados de entre 1890 e 1905 e a história do litopônio na indústria de pigmento no final do século XIX e início do século XX. Apesar de ter muitas qualidades desejáveis para o uso em aquarela branca ou tintas a óleo, o desenvolvimento do litopônio como um pigmento de artistas foi prejudicado por sua tendência a se escurecer na luz solar. Sua disponibilidade para e uso por parte de artistas ainda não está clara, uma vez que os catálogos comerciais dos vendedores de tintas geralmente não eram explícitos na descrição de pigmentos brancos como algo que contém litopônio. Além disso, o litopônio pode ser confundido com o branco de chumbo durante o exame visual e sua fosforescência de curta duração pode ser facilmente perdida pelo observador desinformado. O litopônio fosforescente foi documentado em apenas um outro trabalho até hoje: uma aquarela de Van Gogh. Além da história da manufatura do litopônio, o artigo detalha o mecanismo para a sua fosforescência e sua identificação auxiliada pela espectroscopia de Raman e espectrofluorimetria.
This study & others have lead France to ban Titanium Dioxide as a Food Additive.
- Take the blade cord for example, the quality of the cord and the shape and direction of the surface barbs are what consumers need to consider. Professional materials in use can meet the needs of most consumers for materials, and the quality of these products is certainly to withstand the test, so if you really can not make up your mind, choose what kind of barbed rope, it is recommended to choose the best blade barbed rope.
- The most obvious difference in a short time is the cross section of this piece, hot dip galvanized barbed wire because of surface anticorrosion treatment, so there will be rust in the cross section of this piece, and stainless steel barbed wire because the internal raw materials and surface raw materials are consistent, so there is no such situation.
The different spacing of the thorn rope is mainly in order to save costs to consider, because if they are too close, then obviously a little waste of resources, but the installation is too sparse will not work. Usually the bottom spacing is about 10cm, and the top is up to 20cm, this is because the higher the place is more difficult to climb over, usually more than one meter without the help of tools it is difficult for ordinary people to climb over, and the bottom because of the relatively tight can prevent personnel from drilling in the past.
- Determine the size of the crate based on the actual size of the dog as an adult. In general, the cage should be three times the size of the dog’s body, so that the dog has enough room to turn around and so on.
- According to the different requirements of the industry, in the smelting furnace in accordance with the standard deployment, put the alloy ingot different weight, such as weave, Ming, paper, Lang, silicon, etc., the data out of the smelting is called gold ore. There are gray iron, white iron and the above-mentioned combined gold ore channels, each of which has its own distinctive characteristics, so they are used in industrial exploration and selection according to their own distinctive characteristics.
- Arrived in other ways can’t end effect of the inclination of hook flower network structure in essence is void, water permeability, the natural effect of groundwater and filtering effect has a strong inclusive, suspended in the water content and silt accumulation in fill in crevices, applied to mountain protection, is conducive to the growth of natural plant, beautify the grass spraying to arrive late his curing effect, Gradually restoring the original ecological environment is a perfect link between beautification and protection.
- The form of installation: in the top with the various cage tied together at least as wrapped stone cage net that combination closely not easy to use bad. If the local bandaging is appropriate, it can increase the stability of the structure. There are a lot of grid edge, if the stone cage net only hook in the cage edge and not prepared in the cage edge, even in loose.
Post time: 31-01-23- In fact, although galvanized hook net is a useful material for iron products, but fundamentally speaking, modern hook net through continuous transformation and improvement, even if it seems to be not useful products, also have a role in its use, here we can turn our attention to people abandoned galvanized hook net.
Excellent anticorrosive makes its popularity in the feed, the net surface smooth and tidy, increased the look and feel, can be adornment effect, this characteristic makes it to show in the mining industry, due to high quality with low carbon materials as raw materials, to make it unique general iron mesh screen does not have flexibility, determine its plasticity in use process, Thus can be used in the hardware process of deep processing and manufacturing, complex wall batch swing, underground leakage prevention cracking, light mesh body, so that the cost is much lower than the cost of iron screen, more able to understand its economic and practical.
Post time: 08-08-22- The tensile resistance of welding net to 120N, otherwise for unqualified welding net. In this respect, there is no simple way to test the tensile resistance of the welding net, only through professional tools, expert testing to test, we will not introduce in detail. The outcrop on both sides of the welding net should not exceed 2MM. The welding net diameter wire and weft wire crossing place should be welded firmly, but the edge of the welding net to weld firmly weft wire must come out some, to weld firmly, but can not come out too much, generally not more than 2 mm is qualified welding net.
- If adult dogs touch noses with puppies out of affection, adult dogs touch noses with dogs that have more meaning in life. For example, dogs can touch their noses to communicate where food is safe and whether people or other animals are in danger.
Post time: 29-05-23- 4. When the dog is tired or nervous, it can enjoy its own private space in the cage and let it have a good rest.
Post time: 22-03-235, the guardrail cavity is equipped with galvanized steel lining or aluminum alloy to strengthen, with enough strength and impact resistance, so that the guardrail has the strength and beauty of steel. Stainless steel welding mesh can be used in the construction industry, highway, bridge for reinforcement. Used for mechanical protection, industry, agriculture, construction and so on.
- For example, in gray iron, its carbon exists in iron ore in graphite condition, the crack is often gray, soft and strong, simple filtering, suitable for casting. In white iron, its carbon and iron together into iron carbide, crack appears white, very strong and brittle quality, for the material of malleable steel. The alloy grade consists of various alloying elements with different compositions and structures.
Hot dip galvanizing is then oiled and chromed. The quality of hot-galvanized sheet produced by this method is significantly improved compared with that by wet galvanizing method. It is only valuable for small-scale production. Continuous galvanizing production line includes a series of pretreatment procedures, such as alkali degreasing, hydrochloric acid pickling, water washing, solvent coating, drying, etc., and the original plate needs to be annealed in cover furnace before entering the galvanizing line.
Large coil galvanized wire is made of high quality low carbon steel wire rod processing, is made of high quality low carbon steel, after drawing molding, pickling rust removal, high temperature annealing, hot dip galvanized. Cooling process and other processing. Galvanized wire is divided into hot galvanized wire and cold galvanized wire. Galvanized wire in the process of smelting there are a lot of need to pay more attention to the place, galvanized wire products in the manufacturing process will experience a lot of process, of which the following galvanized wire annealing is a very important step, this step to the nature of galvanized wire has brought a lot of help.
- Second, positive and negative twisting rope cost-effective