1,762 research outputs found
Interface structure of poly(ethylene terephthalate)/silica nanocomposites
No full textThe interface structure of the poly(ethylene terephthalate) (PET)/silica nanocomposites was characterized by Fourier transform infrared and solid-state nuclear magnetic resonance. Our study reveals that PET chains are grafted onto the surface of silica nanoparticles, and they form branched and lightly crosslinking structures during the polycondensation. Gel permeation chromatography measurements
indicate that the grafted PET chains have a lower molecular weight and broader distribution. Furthermore,a model has been developed to elucidate the interaction of an entanglement network between silica and PET chains that lead to enhancements of G′, G〞and η* values of PET/2 wt% silica
nanocomposites.The interface structure of the poly(ethylene terephthalate) (PET)/silica nanocomposites was characterized by Fourier transform infrared and solid-state nuclear magnetic resonance. Our study reveals that PET chains are grafted onto the surface of silica nanoparticles, and they form branched and lightly crosslinking structures during the polycondensation. Gel permeation chromatography measurements
indicate that the grafted PET chains have a lower molecular weight and broader distribution. Furthermore,a model has been developed to elucidate the interaction of an entanglement network between silica and PET chains that lead to enhancements of G′, G〞and η* values of PET/2 wt% silica
nanocomposites
Preparation and Characterization of Poly(butylene terephthalate)/Silica Nanocomposites
No full textIn this study, we presented a convenient, in situ polymerization route for the preparation of Poly (butylene
terephthalate) (PBT)/silica nanocomposites, in which silica was not premodified. The nanocomposites were synthesized by in situ polymerization of terephthalic acid (TPA), 1,4-butanediol (BD) and silica. The structure of these nanocomposites were investigated by Fourier transform infrared (FTIR) and thermogravimetric analyses (TGA). The results show that PBT chains were successfully grafted onto the surface of silica. Transmission electron microscope (TEM) micrographs revealed that silica were homogeneously dispersed in PBT matrix at a size level of 10–20 nm. The isothermal crystallization kinetics of pure PBT and PBT/silica nanocomposites were investigated by differential scanning calorimeter (DSC) and simulated by Avrami model.
The existence of silica could lead to an acceleration of
crystallization and enhance the thermal stability of
PBT. According to dynamic mechanical analysis (DMA),
the storage modulus of PBT/silica nanocomposites
were markedly improved compared with pure PBT.In this study, we presented a convenient, in situ polymerization route for the preparation of Poly (butylene
terephthalate) (PBT)/silica nanocomposites, in which silica was not premodified. The nanocomposites were synthesized by in situ polymerization of terephthalic acid (TPA), 1,4-butanediol (BD) and silica. The structure of these nanocomposites were investigated by Fourier transform infrared (FTIR) and thermogravimetric analyses (TGA). The results show that PBT chains were successfully grafted onto the surface of silica. Transmission electron microscope (TEM) micrographs revealed that silica were homogeneously dispersed in PBT matrix at a size level of 10–20 nm. The isothermal crystallization kinetics of pure PBT and PBT/silica nanocomposites were investigated by differential scanning calorimeter (DSC) and simulated by Avrami model.
The existence of silica could lead to an acceleration of
crystallization and enhance the thermal stability of
PBT. According to dynamic mechanical analysis (DMA),
the storage modulus of PBT/silica nanocomposites
were markedly improved compared with pure PBT
XY displacement device
No full textAn XY-displacement device (1) with a four-fold symmetry comprises a reference frame (10); an object mount (20) for holding an object (22) to be displaced; an X-manipulator (100) coupled between the reference frame (10) and the object mount (20), which provides a rigid coupling between the object mount (20) and a piezoelectric X-actuator (140), allows a Y-displacement of the object mount (20) relative to the reference frame (10), and counteracts a Z-displacement of the object mount (20) relative to the reference frame (10); ; and a Y-manipulator (200) coupled between the reference frame (10) and the object mount (20), which provides a rigid coupling between the object mount (20) and a piezoelectric Y-actuator (240), allows an X-displacement of the object mount (20) relative to the reference frame (10), and counteracts a Z-displacement of the object mount (20) relative to the reference frame (10).Applied Science
A Programmable and Reconfigurable Photonic Simulator for Classical XY Models
No full textIn this work, we proposed and experimentally demonstrated a photonic
simulator for XY models, which is a typical kind of classical spin models. By
encoding the XY spins on the phase term of the input light field, the
corresponding XY Hamiltonian could be performed on the output light
intensities. The simulator is mainly based on a programmable and reconfigurable
optical vector-matrix multiplication system, which can map arbitrary XY models
within the dimensionality limit. Here, we demonstrated the
Berezinskii-Kosterlitz-Thouless transition in a two-dimensional XY model, in
which the expectation values of some observables are calculated and consistent
with the theory. Besides, we performed the ground state search of two 25-spin
XY models with different spin connections and coupling strengths. Our proposal
paves a new way to investigate the XY spin system
A Programmable and Reconfigurable Photonic Simulator for Classical XY Models
No full textThe classical spin models attracts growing interests since many optimization problems can be mapped to searching the ground states of these models. However, solving such problems on conventional computers requires exponentially growing resources. In this work, we proposed and experimentally demonstrated a photonic simulator for classical XY models. By encoding the XY spins on the phase term of the input light field, the corresponding XY Hamiltonian could be performed on the output light intensities. The simulator is mainly based on a programmable and reconfigurable optical vector-matrix multiplication system, which can map arbitrary XY models within the dimensionality limit. We first demonstrate the Berezinskii-Kosterlitz-Thouless transition in a two-dimensional XY model, in which the expectation values of some observables are calculated and consistent with the theory. Besides, we performed the ground state search of two 25-spin XY models with different spin connections and coupling strengths. Our proposal paves a new way to investigate the XY spin system
Three-Year, Randomized, Sham-Controlled Trial of Dexamethasone Intravitreal Implant in Patients with Diabetic Macular Edema
No full textPurpose: To evaluate the safety and efficacy of dexamethasone intravitreal implant (Ozurdex, DEX implant) 0.7 and 0.35 mg in the treatment of patients with diabetic macular edema (DME). Design: Two randomized, multicenter, masked, sham-controlled, phase III clinical trials with identical protocols were conducted. Data were pooled for analysis. Participants: Patients (n = 1048) with DME, best-corrected visual acuity (BCVA) of 20/50 to 20/200 Snellen equivalent, and central retinal thickness (CRT) of >= 300 mu m by optical coherence tomography. Methods: Patients were randomized in a 1:1:1 ratio to study treatment with DEX implant 0.7 mg, DEX implant 0.35 mg, or sham procedure and followed for 3 years (or 39 months for patients treated at month 36) at = 15-letter improvement in BCVA from baseline at study end. Safety measures included adverse events and intraocular pressure (IOP). Results: Mean number of treatments received over 3 years was 4.1, 4.4, and 3.3 with DEX implant 0.7 mg, DEX implant 0.35 mg, and sham, respectively. The percentage of patients with >= 15-letter improvement in BCVA from baseline at study end was greater with DEX implant 0.7 mg (22.2%) and DEX implant 0.35 mg (18.4%) than sham (12.0%; P <= 0.018). Mean average reduction in CRT from baseline was greater with DEX implant 0.7 mg (-111.6 mu m) and DEX implant 0.35 mg (-107.9 mu m) than sham (-41.9 mu m; P < 0.001). Rates of cataract-related adverse events in phakic eyes were 67.9%, 64.1%, and 20.4% in the DEX implant 0.7 mg, DEX implant 0.35 mg, and sham groups, respectively. Increases in IOP were usually controlled with medication or no therapy; only 2 patients (0.6%) in the DEX implant 0.7 mg group and 1 (0.3%) in the DEX implant 0.35 mg group required trabeculectomy. Conclusions: The DEX implant 0.7 mg and 0.35 mg met the primary efficacy endpoint for improvement in BCVA. The safety profile was acceptable and consistent with previous reports. (C) 2014 by the American Academy of Ophthalmology
Draft of Marketing Strategy for XY Company in Specialisation of Industrial Cooling
No full textAutorka diplomové práce si jako téma vybrala Návrh marketingové strategie pro společ-nost XY v oboru průmyslového chlazení. V teoretické části na základě rešerše odborné literatury autorka práce si objasní pojmy, které souvisí s tématem diplomové práce. V praktické části provede analýzy vnitřního a vnějšího prostředí firmy XY pomocí kvalitativního výzkumu a vlastního sběru dat. V projektové části se o závěry z těchto analýz bude opírat při zpracování marketingové strategie firmy XY. Vzhledem k tomu, že se jedná o velmi citlivé informace, bude místo názvu firmy používat označení společnost XY.The author of the thesis chose as the topic the draft of Marketing strategy for the XY company in the field of industrial cooling. The author of the work explains terms related to the topic of the thesis in the theoretical part, which is based on technical literature. In the practical part the analysis of internal and external environment of the XY company is acomplished by means of qualitative research and author's own data collection. There is also the conclusion of these analyzes based on the marketing strategy of the XY company in the project part of the work. Taking into consideration using very sensitive information, author uses in the dissertation the XY name for the original company which the work si based on.Ústav marketingových komunikac
Comparative analysis of LLM capabilities and their implementation potential in business workflows
No full textCompany XY is still growing and the processes have changed over the last few years. Therefore, they have never been drawn and analyzed systematically to see if there is any potential for optimization. For this reason, the author was commissioned to do so, and the following research questions have emerged: Are large language models capable of optimizing internal processes? What processes can be optimized? How can they be implemented? And what is the impact of set implementations? The goal of this paper is to get insights into the state of the processes and possible optimizations with a LLM
Marketing Communications of the Firm XY, s.r.o.
No full textThis thesis helps to understand the problems of marketing communication in business-to-business market. The main intention is to show the theoretical background on the example of real company called XY, s. r. o. The author tried to get familiar with the current company marketing communications and applied the theoretical knowledge, especially in the proposals to improve this communication
Scanning the critical fluctuations: Application to the phenomenology of the two-dimensional XY model
No full textWe show how applying field conjugated to the order parameter may act as a very precise probe to explore the probability distribution function of the order parameter. Using this “magnetic-field scanning” on large-scale numerical simulations of the critical two-dimensional XY model, we are able to discard the conjectured double-exponential form of the large-magnetization asymptote.DelftChemTechApplied Science
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