Thermally responsive hydrogels have drawn significant research attention recently because of their simple use as drug carrier at human body temperature. Here we design a hybrid hydrogel that incorporates a hydrophilic...
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Thermally responsive hydrogels have drawn significant research attention recently because of their simple use as drug carrier at human body temperature. Here we design a hybrid hydrogel that incorporates a hydrophilic polymer, polyethyleneimine (PEI), into the thermally responsive hydrogel poly( N ‐isopropylacrylamide) (PNIPAm), as a general drug carrier model for controlled drug release. In this work, on one hand, PEI modifies the structure and the size of the pores in the PNIPAm hydrogel. On the other hand, PEI plays an important role in tuning the water content in the hydrogel and controls the water release rate of the hydrogel below the lower critical solution temperature (LCST), resulting in a tunable release rate of the drugs at human body temperature (37 °C). Different release rates are shown as different amounts of PEI are incorporated. PEI controls the release rate, dependent on the charge characteristics of the drugs. The hydrogel blends described in this work extend the concept of a general drug carrier for loading both positively and negatively charged drugs, as well as the controlled release effect.
Measurements of physical properties, including transport and magnetic properties, specific heat, and thermal conductivity, have been performed on high-quality samples of LaNiO3 and LaCuO3 synthesized under high pressu...
Measurements of physical properties, including transport and magnetic properties, specific heat, and thermal conductivity, have been performed on high-quality samples of LaNiO3 and LaCuO3 synthesized under high pressure. Some measurements, such as thermoelectric power and magnetic susceptibility, have been made under high pressure. The availability of a complete set of data enables a side-by-side comparison between these two narrowband systems. We have demonstrated unambiguously the mass enhancement due to electron-electron correlations in both systems relative to the recent density functional theory results. Correlations in these narrowband systems also enhance the magnetic susceptibility. Ferromagnetic spin fluctuations give rise to a strong Stoner enhancement in the magnetic susceptibility in the quarter-filled LaNiO3. Although we are able to tune the bandwidth by either chemical substitutions or by applying hydrostatic pressure on LaNiO3, the Stoner enhancement does not lead to the Stoner instability.
The temperature distribution in the vicinity of the laser used in direct metal deposition (DMD) plays a critical role in determining the final microstructure and mechanical properties of the deposit and the heat-affec...
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The contribution deals with prediction of tensile properties based on measurement of microhardness. First of all, the database of stress - strain, σ-Ε vs. hardness data was created. Tensile strength, yield strength,...
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Zirconia (ZrO2) as a ceramic biomaterial facilitates the osteoconductivity in new bone formation around implant. In order to improve the degradation and the surface properties, it is necessary to apply a surface film ...
Zirconia (ZrO2) as a ceramic biomaterial facilitates the osteoconductivity in new bone formation around implant. In order to improve the degradation and the surface properties, it is necessary to apply a surface film to satisfy multiple clinical requirements such as mechanical strength, biocompatibility, and degradation rate. Therefore, surface changing to form a tenacious, biocompatible and corrosion resistant modified layer has become a necessary study in biodegradable materials. The aim of the study is to observe the morphology, structural and scratch analysis for some coatings of ZrO2-CaO and ZrO2-Y2O3 having similar thickness deposited with an atmospheric plasma spraying facility, Sulzer Metco 9MCE, using scanning electron microscopy and X-Ray diffraction. Some mechanical aspects were highlighted during the scratch test. Comparative scratch tests were carried out to study the bonding properties between the coatings and the substrates.
Energy consumption of buildings worldwide has steadily increased over the past couple of decades. Furthermore, energy performance of buildings is one of the factors that contribute to energy waste and its perennial ad...
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ISBN:
(纸本)9780983762430
Energy consumption of buildings worldwide has steadily increased over the past couple of decades. Furthermore, energy performance of buildings is one of the factors that contribute to energy waste and its perennial adverse impact on the environment. This paper presents a data mining approach for assessing the heating and cooling requirements of residential buildings. The proposed approach combines Artificial Neural Networks (ANNs) and cluster analysis to assess and predict the heating and cooling energy efficiency of residential buildings. The ANN-based model uses eight input variables (i.e., relative compactness, surface area, wall area, roof area, overall height, orientation, glazing area, and glazing area distribution) to predict both the heating and cooling loads of residential buildings. Buildings are then clustered based on the output variables using the K-means clustering method. The proposed approach is used to assess and evaluate 768 diverse residential buildings based on simulated literature data. The research results showed that the proposed approach can effectively predict the heating and cooling requirements of residential buildings based on the input variables considered with a very high level of accuracy.
The thermoset pultrusion consists of two sequential steps. First, the dry reinforcement, usually in a tape form, is impregnated with resin as it passes through a resin bath or a pressurized infusion chamber. In the se...
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The thermoset pultrusion consists of two sequential steps. First, the dry reinforcement, usually in a tape form, is impregnated with resin as it passes through a resin bath or a pressurized infusion chamber. In the second step, the saturated preform is further compacted in a heated die and resin cures before it leaves the die. The process model aims to provide a set of predictive tools that relate controllable process parameters - such as speed and temperature - and properties of constituent materials to predict the properties of manufactured composite such as degree of cure and void content. In this study, we present a model to describe the heat transfer and cure during step 2 of the process. The formulated model simulates the heating and the curing stage within the die to predict the exit temperature and conversion state of the composite. Characterization of the material properties is described and provided as input to the process model. Experimental setup to measure the temperature during the pultrusion process both at fixed locations and by sensors embedded in the moving reinforcement is presented. Finally, the experimental results are discussed and model verification is addressed.
In this study the structure and properties of surface-alloyed cp-titanium layers obtained by non-vacuum electron beam cladding of niobium carbide powders were analyzed. A thickness of coatings fabricated by single-lay...
In this study the structure and properties of surface-alloyed cp-titanium layers obtained by non-vacuum electron beam cladding of niobium carbide powders were analyzed. A thickness of coatings fabricated by single-layer cladding was 1.3 mm. Cladding of the second layer led to an increase in the thickness by 0.8 mm. It was found that titanium carbide particles of different morphology acted as strengthening structural elements. The X-ray diffraction (XRD) analysis revealed the presence of α-Ti (α'-Ti), β-Ti, and TiC in the cladded layer. The results of the energy dispersive X-ray (EDX) analysis indicated the presence of Nb in the titanium matrix as well as in the carbide phase. However, such phases as NbC and (Nb, Ti)C were not identified by the XRD analysis. Transmission electron microscopy (TEM) revealed zones containing an increased amount of Nb. The structure of these zones was represented by the β-Ti and ω-Ti precipitation. An average microhardness value of cladded layers was approximately 330 HV.
CaCrO3 is at the crossover from localized to itinerant electronic behavior, and interpretation of its electronic state has remained controversial. It is a metal from an optical study. However, the collinear type-C ant...
CaCrO3 is at the crossover from localized to itinerant electronic behavior, and interpretation of its electronic state has remained controversial. It is a metal from an optical study. However, the collinear type-C antiferromagnetic spin ordering below TN≈90K is characteristic of localized electron magnetism. We have performed many runs of high-pressure synthesis. CaCrO3 crystals can be found in some batches. We have used specific-heat measurement as a diagnostic tool to probe the electronic states near the Fermi energy. An electronic bandwidth is broadened by applying high pressure. The magnetization measurement under pressure reveals a dTN/dP<0. The crystal structural change corresponding to the pressure-induced electron structural change has been monitored by in situ neutron diffraction under high pressure. The t22 d-electron configuration on octahedral site Cr4+ is orbitally threefold degenerate. Local site distortions are argued to show that in CaCrO3 the crossover from localized to itinerant 3d electrons does not result in a charge-density wave in which segregation of the interatomic interactions results in the stabilization of molecular clusters, but in an intraatomic orbital ordering that stabilizes a half-filled localized-electron xy orbital and a 1/4-filled c-axis π* band. Local structural changes under pressure reveal a weakening of long-range magnetic order is associated with a smooth Mott-Hubbard transition of the xy electrons.
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