Highly effective transfer of micro-LED pixels to the intermediate and rigid substrate with weak and tunable adhesion by thiol modification.

Based on transfer printing technology, micro-LED pixels can be transferred to different types and sizes of driving substrates to realize displays with different application scenarios. To achieve a successful transfer, GaN-based micro-LEDs first need to be separated from the original epitaxial substrate. Here, micro-LED pixels (each size 25 µm × 30 µm) on the sapphire substrate were transferred to a flexible semiconductor wafer processing (SWP) tape that is strongly sticky by conventional laser lift-off (LLO) techniques. The pixels on the SWP tape were then transferred by using a sacrificial layer of non-crosslinked oligomeric polystyrene (PS) film onto the intermediate and rigid substrate (IRS) with weak and tunable adhesion by thiol (-SH) modification. The electrode of the micro-LED is Au metal, which forms Au-S bonds with the surface of the IRS to fix the pixels. The rigid substrate helps ensure that the pixel spacing is almost unchanged during the stamp transfer process, and the weak and tunable adhesion facilitates the pixels being picked up by the stamp. The experimental results demonstrate that the pixels can be efficiently transferred to the IRS by LLO and sacrificial layer-assistance, which will provide the possibility of achieving the further transfer of pixels to different types and sizes of driving substrates by a suitable transfer stamp. The transfer process details are discussed, which can provide insights into the transfer of micro-nano devices through polymer sacrificial layers.

Bagasse Cellulose Grafted with an Amino-Terminated Hyperbranched Polymer for the Removal of Cr(VI) from Aqueous Solution.

A novel bio-adsorbent was fabricated via grafting an amino-terminated hyperbranched polymer (HBP-NH2) onto bagasse cellulose. The morphology and microstructure of the HBP-NH2-grafted bagasse cellulose (HBP-g-BC) were characterized and its adsorption capacity for Cr(VI) ions in aqueous solutions was investigated. The rough surface structure of HBP-g-BC that is beneficial for improving the adsorption capacity was observed by scanning electron microscopy (SEM). The grafting reaction was confirmed by Fourier-transform infrared (FT-IR) spectroscopy. The adsorbent performance was shown to be better with a lower pH value, a higher adsorbent dosage, or a higher initial Cr(VI) concentration. Moreover, the kinetics study revealed that the adsorption behavior followed a pseudo-second-order model. The isotherm results showed that the adsorption data could be well-fitted by the Langmuir, Freundlich, or Temkin models. Moreover, HBP-g-BC could maintain 74.4% of the initial removal rate even after five cycles of regeneration. Thus, the high potential of HBP-g-BC as a bio-adsorbent for heavy metal removal has been demonstrated.

[Strategic framework for cholera prevention and control in Chengdu: construction and effectiveness evaluation].

OBJECTIVE: To construct an operable strategic framework for cholera prevention and control which mobilized the advantages of local resources and adapted to social developments in Chengdu, and to evaluate its application effects. METHODS: (1) After analyzing the local epidemic data of cholera in Chengdu from 1994 to 2004, we determined the main problems of cholera prevention and control works as well as the efficiency and deficiency of employed measures, and then formed a basic strategic framework. (2) After 55 invited experts preliminarily scored the strategic framework, we selected 72 specific measures to establish a measure entry database, and then the importance and operability of each measure were scored by 17 core experts. (3) Finally, the effectiveness of this strategic framework was evaluated according to the analyzing results of infection control, health education and etiological monitoring. RESULTS: (1) The framework took government leadership as main scenario and the informatization as subordination scenario. Meanwhile, it focused on three points: the improvement of social environment, the completion of system and mechanisms for monitoring and early warning, and the enhancement of CDC response to public health emergencies. Total importance score and operability score of 35 specific measures included in this framework was 4.20 ± 0.86 and 4.09 ± 0.87, respectively. (2) Chengdu had maintained zero cholera incidence for five consecutive years from 2005 to 2009 since it gradually began to implement the strategic framework in 2002. There were 19 positive cholera cases detected by etiological monitoring and all of them were seafood or fishery products including soft-shelled turtles, silver carps and bullfrogs. The coverage rate and qualification rate of the training for grassroots cadres, grassroots medical workers, mobile cooks and their assistants was 98.14% (198 452/202 220) and 98.17% (194 820/198 452) in average, respectively. The qualification rate of the training for employees in food industry was over 96.00% (912 470/950 489). The average awareness rate of cholera prevention and cure knowledge in rural residents, grassroots cadres, grassroots medical workers, mobile cooks and their assistants was 93.87% (1653/1761) and the average formation rate of good hygiene habits was 70.58% (1243/1761). CONCLUSION: A strategic framework suitable for cholera prevention and control in Chengdu has been successfully established in this study. The incidence rate of cholera has maintained zero in Chengdu for five consecutive years under incessant threatening conditions such as the occurrence of cholera cases from time to time in its surrounding areas and the continuous existence of Bacillus comma in seafood or fishery products that entered local markets. Therefore, it demonstrated a good application effects.