CERAMICS INTERNATIONAL
·
2018
·
IF 3.057
Jingkun Yuan,Peigang He,Xiaomin Liang,Dechang Jia,Lingyu Jia,Delong Cai,Zhihua Yang,Xiaoming Duan,Shengjin Wang,Yu Zhou
In this paper, a high temperature treatment procedure was designed to evaluate the effect of holding temperature on thermal evolution process of Li + substituted Cs-based geopolymer (Cs 0.7 Li 0.3 GP), including the thermal analysis, phase composition and microstructure evolution. With rising of holding temperature, amorphous unheated Cs 0.7 Li 0.3 GP gradually transformed into a multiphase system during the high temperature treatment process, which consisted of pollucite (CsAlSi 2 O 6 ), spodumene (LiAlSi 2 O 6 ) and amorphous glass phase. In the multiphase system, Cs + ions were in the form of pollucite grains, while Li + ions were in the form of spodumene nanocrystallines distributed in amorphous matrix. The pollucite grains gradually coarsened with rise in holding temperature, and the densification of the resulting products were also improved synchronously, which were related to the presence of amorphous glass phases. The amorphous glass phase would be in a molten state when holding temperature over 800 °C. And the presence of molten amorphous phase would make the mass transfer process easier, which could contribute to the growth of the crystal grains and the elimination of the pores.
研究领域:
材料科学
·
地质学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
·
2016
·Vol. 99
·期 11
·3784-3791
·
IF 2.787
Jingkun Yuan,Peigang He,Chao Yang,Dechang Jia,Jinsong You,Shu Yan,Delong Cai,Zhihua Yang,Xiaoming Duan,Shengjin Wang,Jiahuan Xu,Yu Zhou
The purpose of this work was to study the role of lithium in cesium-based geopolymers and the thermal evolution during heat treatment together with thermal expansion behavior of the resulting geopolymer ceramic. A series of lithium-substituted cesium-based geopolymers, Cs (1− x ) Li x GP (where x = 0, 0.1, 0.2, and 0.3), were prepared. All the geopolymer samples were heated at 1300°C for 2 h and thermal evolution on heating was studied by a variety of techniques. Phase composition, microstructure evolution, and thermal expansion behaviors of the ceramics derived from the geopolymers were characterized. All the geopolymer specimens exhibited similar thermal evolutionary trends. With increases in lithium content, overall mass loss increased gradually due to the higher hydration energy of Li + than Cs + . Thermal shrinkage of these specimens can be divided into four stages, i.e., structural resilience, dehydration, dehydroxylation, and sintering, according to the dilatometer results. The introduction of Li results in two-step sintering behavior for the lithium-substituted cesium-based geopolymers. The average thermal expansion coefficient (CTE) of Cs (1− x ) Li x GP ceramics decreased from 4.80 × 10 −6 K −1 ( x = 0) to 3.61 × 10 −6 K −1 ( x = 0.3) with increase in lithium substitution. The reason can be attributed to the presence of spodumene after thermal treatment, which has a relatively low thermal expansion coefficient compared with pollucite. Meanwhile, molten spodumene could serve as a buffer phase between pollucite crystals also conducive to the decline of CTE of this system.
研究领域:
材料科学
·
无机非金属材料
·
陶瓷学
·
热物理性能
·
固废资源化
✓ 已验证
DOI
高影响因子
APPLIED THERMAL ENGINEERING
·
2025
·
IF 6.9
Wenxin Zhu,Kunliang Yao,Ruijiao Miao,Sha Han,Zheng Li,Yuqing Han,Yonghua Huang
Successful cryopreservation and revival rely on effective cooling and rewarming strategies. Rewarming processes are more vital, because insufficient rewarming normally leads to devitrification or recrystallization, resulting in irreversible damage to biomaterials. Conventional rewarming methods often fail to achieve the required super-high rates. Laser warming has emerged as a promising approach for achieving ultra rapid and internalized heating. Most studies on laser rewarming rely heavily on simulations and lack experimental validation. Moreover, conventional procedures require the manual transfer of vitrified samples from liquid nitrogen to laser exposure spot, which introduces operational risks. To address these limitations, an integrated platform combining vitrification-based cryopreservation with automated laser rewarming was developed. A fast-response temperature measurement system was incorporated to monitor the real-time thermal changes in samples during laser irradiation. The laser rewarming rate of a 1 μL droplet was measured to be 3.5 × 10 6 K/min, which is far beyond those achieved by conventional water bath methods and significantly higher than the required critical warming rate. Three distinct temperature evolution modes were observed: insufficient, appropriate, and excessive heating. We directly confirmed a temperature overshoot followed by rapid thermal decay immediately after laser exposure, which has never been reported before. By varying the laser energy and beam size, the extent of temperature overshoot and subsequent thermal relaxation were controlled, which enabled the optimization of laser rewarming strategy. The findings can be used for the refinement of numerical models and will contribute to the development of safer and more effective rewarming protocols in the cryopreservation field.
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）