Calcium phosphate biocomposites are candidate materials for bone tissue engineering due to their conductivity and biocompatibility. Calcium phosphate could be grown on collagen by precipitation method in long reaction time. Microwave irradiation is rapid method to assist precipitation by reducing reaction time. In order to study carbonated calcium phosphate precipitation on collagen and investigate the influence of microwave irradiation time, the carbonated calcium phosphate has been grown on collagen by microwave assisted precipitation method. The collagen sheets were soaked in carbonated calcium phosphate suspension prepared by using Ca(NO3)2.4H2O, (NH4)2HPO4, and NaHCO3 as starting materials, then microwave irradiated at 270 Watt for 2 minutes, 8 minutes, and 16 minutes. X-ray powder diffraction (XRD) pattern shows the transformation of dicalcium phosphate dyhydrate to apatite crystal structure. Increase in irradiation time had increased crystallinity of carbonate apatite phase. FTIR spectrum had confirmed presence of collagen, phosphate, and carbonate functional group. Scanning electron micrograph showed the presence of collagen with pore, and the carbonated calcium phosphate could attach and be deposited onto collagen.

Reconstruction of bone defect due to a disease or a trauma can use autograft, allograft, xenograft or synthetic bonegraft as the bone substitute material. However, in particular cases, it is required a material that has a specific resorption characteristic, beside owning excellent bioactive properties, such as β-tricalcium phosphate (β-TCP). In this study, we report the synthesis of β-TCP particles with mesopores structure by using chitosan and aloe vera as templates. A solution of (NH4)2HPO4 was added dropwise into solution of Ca(NO3)2·4H2O and the template at 85°C for 2 hours, and subsequently aged for 3 hours. Then, the formed precipitate was washed and centrifuged repeatedly prior to drying at 80°C for 24 hours. Finally, the dried precipitate was calcined at 900°C for 1 hour to obtain β-TCP powder. Phase identification and mesopores structure were analyzed using X-ray diffraction (XRD), while the existence of functional groups was identified by Fourier-transform infrared (FTIR) spectroscopy. Microstructure and particle size distribution were characterized by scanning electron microscopy (SEM) and particle size analyzer (PSA), respectively. XRD analysis shows that β-TCP is dominant with the presence of small amount of impurities. Furthermore, low angle peak in XRD analysis indicates the formation of mesopores structure. From the SEM and PSA analysis, the morphology of both TCP-K and TCP-KA particles showed more large agglomerates and more heterogeneous particle size distribution due to the addition of the biopolymers in the synthesis of β-TCP.

Lithium-ion battery has been drawing attention from researchers due to its excellent properties in terms of electrochemical and structural stability, low cost, and high safety feature, leading to prospective applications in electric vehicles and other large-scale applications. However, lithium-ion batteries are still in charging time owing to its low conductivity, restricting its wide applications in large-scale applications. In this work, therefore, lithium lanthanum titanate (LLTO) was synthesized derived from lanthanum oxalate, as a lanthanum source, for an anode active material application in the lithium-ion batteries due its high electrochemical conductivity and pseudocapacitive characteristics. To the best our knowledge, our work is the first one to synthesize LLTO from lanthanum oxalate as the lanthanum source. Commercial lithium carbonate and commercial titanium oxide were used as the lithium and titanium sources, respectively. It was used low cost and simple solid-state reaction process to synthesize this material and performed a two-step calcination processs at 800 oC for 8 hours and 1050 oC for 12 hours under ambient atmosphere. The physical characteristics showed that LLTO possesses high purity (98.141%) and micro sized grains with abundant empty spaces between the grains. This, therefore, lead to improve electrochemical performances such as stable discharge capacity at low potential even near to zero (98.67 mAh), and a high conductivity of 2.45 × 10-2 S/cm at room temperature. This LLTO is interesting to be used as the anode active material in low potential lithium-ion battery applications.

Biphasic calcium phosphate (BCP) is a bonegraft material which is a mixture of hydroxyapatite (Ca10(PO4)6(OH)2, HA) and betatricalcium phosphate (Ca3(PO4)2, β-TCP). The combination of HA and β-TCP provides faster osseointegration, compared to HA, into parent bone so it can accelerate the bone recovery process. The mesoporous structure of bone graft material is suitable for drug delivery purpose. In order to study the mesoporous structure of BCP, the BCPs were prepared by precipitation method using chitosan, aloe vera, and chitosan-aloe vera hybrid as templates. A solution containing Ca(NO3)2·4H2O and template and a solution containing (NH4)2HPO4 and NH4HCO3 were used as starting materials. All prepared samples were calcined at 900°C for 1 hour. The identification of phases and functional groups of obtained BCP powders were characterized by X-Ray Diffraction technique and Fourier Transform Infrared (FTIR) spectroscopy, repectively. The XRD patterns show typical peaks of both HA and β-TCP crystal phases. FTIR spectra confirm the presence of phosphate functional groups. Morphological analysis using Scanning Electron Microscope (SEM) observed the presence of regular porous structure, however, the mesoporous structure was not seen. Particle size distribution and pore size analysis were analyzed by Particle Size Analyzer and Brunauer–Emmett–Teller (BET) method, respectively.

Li4Ti5O12 (lithium titanium oxide) or LTO is extensively utilized as active material in Li-ion battery anode mainly due to its zero strain properties and excellent lithium-ion intercalation/deintercalation reversibility with negligible volumetric change. However, LTO is still faced with low electronic conductivity problem, thus the addition of another material such as graphene is necessary to overcome. In this study, LTO was synthesized using sol-gel method with addition of Li varied from 35, 40 and 55 wt% which was controlled by addition of Li2CO3. XRD analysis was performed to investigate the crystal structure and phase characteristic of synthesized powder. The results revealed that LTO with addition of 55 wt% Li exhibited the highest purity of Li4Ti5O12 phase of 97.7%. It was then added with 5 wt% of graphene. Two-coin cells of Li-ion batteries were made from LTO powders without and with graphene addition as active materials for anode and their electrochemical performances were analyzed. LTO without and with graphene show conductivity of 3.40710-5 and 2.48810-5 S/cm, while obtained specific capacity was about 140 mAH and 85 mAh, respectively. This would require further optimization for current experimental condition particularly on graphene addition.

Large contributions of the thermal conductivity due to spins, κspin, in low-dimensional spin systems are expected to be utilized as highly thermal conducting materials. One-dimensional spin system RbFeCl3 with ferromagnetic chains and CsFeBr3 with antiferromagnetic chains in magnetic fields have been prepared in order to observe the contribution of κspin to the value of thermal conductivity. The temperature dependence of the thermal conductivity parallel to spin chains along the c-axis, κ//c, of RbFeCl3 enhanced around 3 K and 10 K by the application of magnetic field. In the thermal conductivity perpendicular to c-axis, κ⊥c, of RbFeCl3, on the other hand, it has been found that only one peak around 3 K is enhanced by the application of magnetic field. Since κ⊥c is mainly owing to the thermal conductivity due to phonons, κphonon, it has been concluded the peak of κ//c around 10 K in magnetic fields is due to the contribution of κspin. For CsFeBr3, it has been found that κ//c shows two peaks around 3 K and 25 K while κ⊥c shows one peak around 12 K in zero field. This indicates that there is a marked contribution of κspin to κ//c. κ⊥ However, the details of the marked contribution of κspin to κ//c are not yet clear, since κ//c has been suppressed by the application of magnetic field in contrast with the enhancement of the thermal conductivity in RbFeCl3.

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