18 results about "Tan delta" patented technology

Provided is a multilayer adhesive for bonding components within a foldable electronic device. The adhesive includes an elastic layer having opposed first and second major surfaces, where a first viscoelastic skin layer disposed on the first major surface and a second viscoelastic skin layer disposed on the second major surface. The elastic layer has a Tan Delta at 70ºC of from 0.02 to 0.20 and each of the first and second viscoelastic skin layers independently has a Tan Delta at 70ºC of from 0.20 to 0.55, with the Tan Delta of each of first and second viscoelastic skin layers being at least 125 percent that of the elastic layer. Advantageously, the multilayer adhesive enables a high degree of crease recovery, while preserving strong adhesion and decoupling bending stresses to avoid damage to functional layers within the foldable electronic device.

The present disclosure relates to polyethylene copolymers. The polyethylene copolymers include 90 wt% or greater ethylene units and a remainder balance of C3-C20 comonomer units. The polyethylene copolymers have a melt index of about 0.1 g / 10min to about 2.2 g / min, a high load melt index (HLMI) of about 10 g / 10 min to about 50 g / 10 min, a melt index ratio (MIR) of about 20 to about 35, a molecular weight distribution (MWD) of about 3 to about 7, a melt strength of about 0.03 N to about 0.10 N, a ∆CWF / ∆T of about wt% / 0.02 °C to about 0.03 wt% / °C, a SignCDI *ɳ0*1032 / (Tan delta (ω=0.1) * MW6.82) of about 2 Pa*s / [(g / mol)6.82]to about 8 Pa*s / [(g / mol)6.82], and a CDI_NWZ,w of about 0.200 to about 0.33.

A display film includes a transparent glass layer having a thickness of 250 micrometers or less, or in a range from 25 to 100 micrometers. A transparent energy dissipation layer is fixed to the transparent glass layer. The transparent energy dissipation layer has a glass transition temperature of 27 degrees Celsius or less and a Tan Delta peak value of 0.5 or greater, or from 1 to 2.

The invention discloses a method for evaluating the aging performance of flame-retardant insulating oil, and relates to the technical field of performance evaluation of insulating materials of power equipment, and the method comprises the following steps: S1, sample preparation; s2, a sequential coupling aging test: sequentially performing an accelerated thermal aging test and a disruptive discharge aging test on the flame-retardant insulating oil sample; s3, performance parameter testing and characteristic rule identification: testing a flash point, a breakdown voltage, a dielectric loss factor tan delta and an acid value of the sample at different stages of the sequential coupling aging test; analyzing an evolution rule of a flash point along with thermal aging time, change characteristics of a breakdown voltage in thermal aging and breakdown discharge aging processes, and change trends of a dielectric loss factor and an acid value; and S4, comprehensive performance and service life evaluation. According to the invention, through a sequential coupling aging test, a complex working condition of a thermal-electric stress synergistic effect in the transformer is comprehensively simulated, and the limitation of a traditional single aging mode is overcome.

The invention discloses glass for a through-hole glass substrate and a preparation method of the glass, and belongs to the technical field of through-hole glass. Comprising the following steps: weighing raw materials according to a ratio, uniformly mixing, melting at 1550-1650 DEG C, homogenizing and clarifying, molding into a required shape, and annealing to finally obtain finished glass. Wherein the thermal expansion coefficient of the finished glass in the range of 50-300 DEG C is (4.0-5.0) * 10 <-6 > / DEG C, and the dielectric loss tangent value tan delta at the frequency of 0.8 GHz is less than 0.003. According to the invention, through a unique component ratio, two properties, namely a proper thermal expansion coefficient and extremely low dielectric loss, which are crucial to TGV application are successfully and perfectly combined together, so that the problem that an existing glass material is difficult to give consideration to the two properties is solved. And the preparation process belongs to a conventional technology, is easy to realize large-scale production, and has a good industrialization prospect.

The invention belongs to the technical field of electronic ceramics, and particularly discloses a low-Curie-temperature medium-entropy lead magnesium tungstate-based ceramic and a preparation method and application thereof, the chemical general formula of the low-Curie-temperature medium-entropy lead magnesium tungstate-based ceramic is Pb (Mg < 1 / 4 > W < 1 / 4 > B '< 1 / 4 > B' < 1 / 4 >) O3, B '= Yb < 3 + > or Lu < 3 + >; b ''= Nb < 5 + > or Ta < 5 + >. According to the low-Curie-temperature medium-entropy lead magnesium tungstate-based ceramic and the preparation method and application thereof, the Curie temperature TC of the lead magnesium tungstate ceramic can be effectively reduced through the method, the dielectric constant is increased, low dielectric loss is kept, and the obtained ceramic has a pure perovskite structure and good compactness; the phase change temperature of the lead magnesium tungstate-based antiferroelectric ceramic ranges from-11 DEG C to-24 DEG C, the maximum relative dielectric constant ranges from 800 to 1100, the maximum dielectric loss tan delta ranges from 0.05 to 0.065, and the problems that an existing lead magnesium tungstate-based antiferroelectric ceramic is high in phase change temperature and low in dielectric constant can be solved.

The invention provides an article having a non-flat geometry, wherein the non-flat geometry can be a sphere or hemisphere formed from a thermoplastic polyurethane having a low tan delta a high rebound and wherein the article demonstrates low hysteresis. The article may be useful in applications such as tennis balls.

Provided is a novel glass sheet that can be used as a substrate or window material for high-frequency devices and has a low propagation loss or transmission loss in a high-frequency band. The glass sheet is a glass sheet having a dielectric loss tangent tan delta A at 10 GHz and a glass transition temperature Tg (°C), and satisfies (tan delta 100 - tan delta A) >= 0.0004 when the dielectric loss tangent is set to tan delta 100 upon heating the glass sheet to (Tg + 50) °C and then cooling it to (Tg - 150) °C at a rate of 100 °C / min.

The application relates to the technical field of functional ceramic materials, in particular to a high-power low-loss piezoelectric ceramic and a preparation method and application thereof. The high-power low-loss piezoelectric ceramic has a chemical formula of Pb(Mn 1 / 3 Sb 2 / 3 ) x Zr 0.51‑x Hf 0.01 Ti 0.48 O3+0.1wt%MnO2+ywt%CuO, wherein 0.03<=x<=0.05 and 0.05<=y<=0.15. The high-power low-loss piezoelectric ceramic has excellent comprehensive performance, d33=350pC / N, kp=0.64, epsilon r=1500, Qm=2000, tan delta (400V / mm)=2.6%, high piezoelectric performance and mechanical quality factor, low high-field loss, and the comprehensive performance is obviously superior to that of a commercially available high-power piezoelectric ceramic.

The invention discloses a chip epoxy resin composition suitable for packaging a hollow structure type electronic device. The composite material is prepared from 55-85 parts of an inorganic filler, 0.25-0.5 part of a coupling agent, 2.7-6.3 parts of I-type epoxy resin, 4-18 parts of II-type epoxy resin, 4.5-14.2 parts of a curing agent, 0.15-0.65 part of a curing accelerator, 3-7.4 parts of thermoplastic resin and 0.15-0.5 part of a coloring agent through the processes of glue preparation, primary coating, drying, semi-curing, secondary laminating, rolling and cutting and the like. The elasticity of the sheet type epoxy resin composition is greater than the viscosity at the use temperature, namely, the physical parameter tan delta (G '' / G ', loss modulus / storage modulus) lt is 0.7 for representing the viscoelastic characteristic, and the sheet type epoxy resin composition can well inhibit flow permeability, so that the packaging requirements of hollow structure type electronic devices are met.

Apparatus and methods are described including an additional lens (24) made from an amorphous viscoelastic material and having an optical design. A curvature of the additional lens (24) is changed such as to conform with a curvature of abase eyeglasses lens (22), without causing a loss of the optical design of the additional lens (24), by heating the additional lens (24) to a temperature at which a Tan Delta of the amorphous viscoelastic material is between 0.2 and 0.8, and shaping the additional lens (24). Subsequently, the additional lens (24) is adhered to the base eyeglasses lens (22). The optical design of the additional lens (24) is such that, upon being adhered to the base eyeglasses lens (22), the adhered base eyeglasses lens (22) and the additional lens (24) provide a combined lens (20) having a desired optical prescription. Other applications are also described.

The invention discloses a high-dielectric high-power low-loss ferrite material and a preparation method thereof, the matrix structure is yttrium iron garnet, the ferrite material belongs to a gyromagnetic ferrite material, the chemical formula of the ferrite material is Y3-a-b-cBiaCabDycZrbIndFe5-b-d-fO12-1. 5f, a is greater than or equal to 0.9 and less than or equal to 1.55, b is greater than or equal to 0.2 and less than or equal to 0.45, c is greater than or equal to 0 and less than or equal to 0.06, d is greater than or equal to 0 and less than or equal to 0.3, and f is greater than or equal to 0 and less than or equal to 0.2. The invention also discloses a preparation method of the ferrite material, the specific gravity of a liquid phase medium is gradually reduced in two times of ball milling, the particle size of the material is reduced, and the particle uniformity is improved. And a sectional sintering process is combined, so that uniform generation of fine grain ferrite is promoted, and precipitation of a second phase is inhibited. According to the ferrite material prepared by the invention, the dielectric constant is 22-31, the ferromagnetic resonance line width is 70-110 Oe, the saturation magnetization is 1600-1950 Gs, and the electromagnetic loss is tan delta epsilon lt; the ferrite material has good performance stability, and can be applied to a small-size ultra-wideband circulator.

Examples relate to a package substrate in which thermal shock resistance, impact resistance, durability, reliability, and the like are improved by adjusting a difference in physical properties between the upper and lower portions of a glass core. An example package substrate includes a glass core, a wiring layer, and an insulating layer, the wiring layer being a conductive layer disposed on a surface of the glass core, the insulating layer being a layer disposed between the conductive layers, the package substrate having an upper surface and a lower surface, the insulating layer disposed on an upper portion of the glass core being an upper insulating layer, and the insulating layer disposed on a lower portion of the glass core being a lower insulating layer. The insulating layer is a glass core, a cover layer is further arranged on the upper portion of the insulating layer, the insulating layer arranged on the lower portion of the glass core is a lower insulating layer, a solder resist layer is further arranged on the lower portion of the lower insulating layer, the flexibility index FI is a value represented by the following formula 1, and the FI of the cover layer has a value larger than the FI of the solder resist layer. FI = 10000 * (E '* tan delta) / (H * Er), in the formula 1, E' is the storage modulus, tan delta is the loss tangent, H is the hardness, and Er is the damping modulus.

The invention discloses a polypropylene cable insulation aging state diagnosis method based on multiple characteristic quantities. The method comprises the following steps: firstly, measuring current values of a dielectric loss angle tangent (Tan delta), a resistance-capacitance current ratio (Ir / Ic) and an insulation resistivity (rho) of a cable; then, calculating the change rate (Ktan delta, Kic, Krho) of the initial reference value relative to the initial reference value; thirdly, performing weighted fusion on the three change rates to obtain a quantized comprehensive aging index (CAI); and finally, according to a preset threshold interval in which the CAI value is located, accurately judging the health, attention, early warning or critical state of cable insulation. According to the method, a plurality of complementary electrical characteristic quantities are fused, the diagnosis result is accurate and reliable, quantitative evaluation of the insulation state of the polypropylene cable can be realized, and key decision support is provided for predictive maintenance.

Apparatus and methods are described including an additional lens (24) made from an amorphous viscoelastic material and having an optical design. A curvature of the additional lens (24) is changed such as to conform with a curvature of a base eyeglasses lens (22), without causing a loss of the optical design of the additional lens (24), by heating the additional lens (24) to a temperature at which a Tan Delta of the amorphous viscoelastic material is between 0.2 and 0.8, and shaping the additional lens (24). Subsequently, the additional lens (24) is adhered to the base eyeglasses lens (22). The optical design of the additional lens (24) is such that, upon being adhered to the base eyeglasses lens (22), the adhered base eyeglasses lens (22) and the additional lens (24) provide a combined lens (20) having a desired optical prescription. Other applications are also described.

The invention relates to the technical field of insulation adhesive film testing, in particular to a vehicle FFC insulation adhesive film low-temperature bending testing method which uses a dynamic thermal mechanical analyzer and adopts a double-cantilever mode for testing and comprises the following steps: S1, sample preparation: cutting an insulation adhesive film into rectangular strips; s2, condition setting: temperature, frequency and amplitude conditions of the dynamic thermal mechanical analyzer are set, the frequency is set to be 0.1 Hz, 0.5 Hz, 1Hz, 5Hz and 20Hz, and the amplitude is + / -15 [mu] m; s3, clamping the two ends of the insulating adhesive film obtained in the step S1, applying a load to the middle of the insulating adhesive film, and starting to test according to the conditions set in the step S2 to obtain a storage modulus E ', a loss modulus E' 'and a loss tangent tan delta; and S4, according to the mathematical model corresponding to the data obtained in the step S3, carrying out cracking evaluation, and solving the problems of simple experimental data, no feedback and large subjective judgment error of a traditional thin film low-temperature bending test.

The invention discloses a cold-sintered lead metaniobate high-temperature piezoelectric ceramic material, and a preparation method and application thereof, the cold-sintered lead metaniobate high-temperature piezoelectric ceramic material is characterized in that the chemical general formula of the cold-sintered lead metaniobate high-temperature piezoelectric ceramic material is m% Ln2O3 + (1-x) PbNb2O6 + xBaTiO3, wherein Ln is a lanthanide element, m represents the percentage of Ln2O3 in the total mole number of (PbNb2O6 + BaTiO3), m is more than or equal to 0.1 and less than or equal to 5.0, and x is more than or equal to 0.01 and less than or equal to 0.2. The material disclosed by the invention can regulate and control lattice defects, domain structures and sintering behaviors of lead metaniobate, can be sintered and molded under a cold sintering process condition, has a compact structure and uniformly distributed crystal grains, can be suitable for a wide temperature range of 25-450 DEG C, has a relatively high piezoelectric coefficient (d33 is greater than 100pC / N at normal temperature), has a fluctuation range of no more than + / -10% along with temperature change, and dielectric loss tan delta is less than or equal to 0.015; the Curie temperature Tc is greater than or equal to 480 DEG C, and excellent high-temperature stability and piezoelectric response performance are achieved.