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"Han, Jiang"
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One-phase-low-pH enzyme induced carbonate precipitation (EICP) method for soil improvement
Enzyme induced carbonate precipitation (EICP) is an emerging soil improvement method using free urease enzyme for urea hydrolysis. This method has advantages over the commonly used microbially induced carbonate precipitation (MICP) process as it does not involve issues related to bio-safety. However, in terms of efficiency of calcium carbonate production, EICP is considered lower than that of MICP. In this paper, a high efficiency EICP method is proposed. The key of this new method is to adopt a one-phase injection of low pH solution strategy. In this so-called one-phase-low-pH method, EICP solution consisting of a mixture of urease solution of pH = 6.5, urea and calcium chloride is injected into soil. The test results have shown that the one-phase-low-pH method can improve significantly the calcium conversion efficiency and the uniformity of calcium carbonate distribution in the sand samples as compared with the conventional two-phase EICP method. Furthermore, the unconfined compressive strength of sand treated using the one-phase-low-pH method is much higher than that using the two-phase method and the one-phase-low-pH method is also simpler and more efficient as it involves less number of injections.
Journal Article
الاقتصاد الصيني : (العقبات والحلول) : أكبر 18 مشكلة اقتصادية تواجه الصين وكيفية حلها
تناول الكتاب بين طياته أكبر 18 مشكلة تواجه الصين وكيفية حلها، وذلك من خلال إجراء الأبحاث والدراسات عن تلك المسائل والقيام بتحاليل وتوصيات لها. ولقد اختيرت هذه القضايا الثمانية عشر من واجب الالتفات إلى الوضع العام لمسايرة الاتجاه مع الأخذ في الاعتبار أهمية وطول مدى القضية، مثل ما هو مخرج الاقتصاد الصيني بعد الأزمة المالية العالمية، كيف تتجنب الصين السقوط في \"فخ\" الدخل المتوسط، كيف تتعامل الصين مع أزمة الموارد المتزايدة الخطورة، هل مستقبل الصادرات الصينينة ما زال مشرقا، كيف تضيق الصين فجوة توزيع الدخل الآخذة في التزايد، لماذا لا يعترف الغرب بوضع اقتصاد السوق الصيني...الخ. وفيما يتعلق بالأجابةعلى هذه الأسئلة، فتستخدم مؤلف الكتاب سياسة \"المراحل الثلاث\"وهي عبارة عن طرح المشكلة وتحليل الأسباب ووضع التدابير المضادة. كما يحتوي كل جواب على أكثر من ثلاثة أجزاء.
BOOK
Red light-driven electron sacrificial agents-free photoreduction of inert aryl halides via triplet-triplet annihilation
Selective photoactivation of inert aryl halides is a fundamental challenge in organic synthesis. Specially, the long-wavelength red light is more desirable than the widely-applied blue light as the excitation source for photoredox catalysis, due to its superior penetration depth. However, the long-wavelength red light-driven photoactivation of inert aryl halides remains a challenge, mainly because of the low energy of the single long-wavelength red photon. Herein, we report the photoreduction of aryl bromides/chlorides with 656 nm LED via triplet-triplet annihilation (TTA) strategy. This method is based on our discovery that the commonly used chromophore of perylene can serve as an efficient and metal-free photocatalyst to enable the photoreduction of inert aryl halides without the conventional need for electronic sacrificial agents. By introducing a red light-absorbing photosensitizer to this perylene system, we accomplish the long-wavelength red light-driven photoreduction of aryl halides via sensitized TTA mechanism. Moreover, the performance of such a TTA-mediated photoreduction can be significantly enhanced when restricting the rotation freedom of phenyl moiety for perylene derivatives to suppress their triplet nonradiative transition, in both small and large-scale reaction settings.
The functionalization of aryl halides via photocatalysis typically involves the use of blue light. Here, the authors report the photoreduction of aryl halides enabled by red light; the method does not require a sacrificial electron donor.
Journal Article
Effect of pH on soil improvement using one-phase-low-pH MICP or EICP biocementation method
One-phase-low-pH MICP (Microbially Induced Carbonate Precipitation) or EICP (Enzyme Induced Carbonate Precipitation) is a new biocementation method for soil improvement. This method uses the low pH of bacterial or urease solution to provide a delay for the MICP or EICP process so that the treatment solution can be evenly distributed in soil during grouting. However, how are the delay duration and the effect of biocementation affected by the initial pH (pH0) of bacterial or urease solution has not been studied. In this paper, an experimental study using different pH0 of urease (or bacterial) solution for EICP (or MICP) biocementation is presented. The study shows that the lower the pH0, the longer the delay period. However, the EICP or MICP process becomes ineffective when the pH0 is equal to or lower than 4.5 or 4.0 for EICP and MICP, respectively. The pH0 also has a significant effect on the strength of treated sand by affecting the morphology and crystallinity of precipitated calcium carbonate crystals. The pH0 on the other hand, has little effect on the amount of calcium carbonate production and its distribution in soil as long as the delay duration is sufficient for the distribution of treatment solution in soil.
Journal Article
Piezoceramic membrane with built-in ultrasound for reactive oxygen species generation and synergistic vibration anti-fouling
Piezoceramic membranes have emerged as a prominent solution for membrane fouling control. However, the prevalent use of toxic lead and limitations of vibration-based anti-fouling mechanism impede their wider adoption in water treatment. This study introduces a Mn/BaTiO
3
piezoceramic membrane, demonstrating a promising in-situ anti-fouling efficacy and mechanism insights. When applied to an Alternating Current at a resonant frequency of 20 V, 265 kHz, the membrane achieves optimal vibration, effectively mitigating various foulants such as high-concentration oil (2500 ppm, including real industrial oil wastewater), bacteria and different charged inorganic colloidal particles, showing advantages over other reported piezoceramic membranes. Importantly, our findings suggest that the built-in ultrasonic vibration of piezoceramic membranes can generate reactive oxygen species. This offers profound insights into the distinct anti-fouling processes for organic and inorganic wastewater, supplementing and unifying the traditional singular vibrational anti-fouling mechanism of piezoceramic membranes, and potentially propelling the development of piezoelectric catalytic membranes.
Piezoceramic membranes in water treatment have been limited by the single vibration-based anti-fouling mechanism. The authors break this limitation using Mn/BaTiO
3
membranes to generate reactive oxygen species via piezoelectric vibration, offering insights for developing piezoelectric anti-fouling and catalytic membranes.
Journal Article
Hidden and doubly heavy molecular states from interactions D(s)(∗)D¯s(∗)/B(s)(∗)B¯s(∗) and D(s)(∗)Ds(∗)/B(s)(∗)Bs(∗)
In this work, we perform a systematical investigation about the possible hidden and doubly heavy molecular states with open and hidden strangeness from interactions of D(∗)D¯s(∗)/B(∗)B¯s(∗), Ds(∗)D¯s(∗)/Bs(∗)B¯s(∗), D(∗)Ds(∗)/B(∗)Bs(∗), and Ds(∗)Ds(∗)/Bs(∗)Bs(∗) in a quasipotential Bethe-Salpeter equation approach. The interactions of the systems considered are described within the one-boson-exchange model, which includes exchanges of light mesons and J/ψ/Υ meson. Possible molecular states are searched for as poles of scattering amplitudes of the interactions considered. The results suggest that recently observed Zcs(3985) can be assigned as a molecular state of D∗D¯s+DD¯s∗, which is a partner of Zc(3900) state as a DD¯∗ molecular state. The calculation also favors the existence of hidden heavy states DsD¯s/BsB¯s with spin parity JP=0+, DsD¯s∗/BsB¯s∗ with 1+, and Ds∗D¯s∗/Bs∗B¯s∗ with 0+, 1+, and 2+. In the doubly heavy sector, the bound states can be found from the interactions (D∗Ds+DDs∗)/(B∗Bs+BBs∗) with 1+, DsD¯s∗/BsB¯s∗ with 1+, D∗Ds∗/B∗Bs∗ with 1+ and 2+, and Ds∗Ds∗/Bs∗Bs∗ with 1+ and 2+. Some other interactions are also found attractive, but may be not strong enough to produce a bound state. The results in this work are helpful for understanding the Zcs(3985), and future experimental search for the new molecular states.
Journal Article
Examining the impact of differing caffeine dosages in conjunction with plyometric training on physiological adaptations in basketball players
The aim of the current study was to investigate the effects of ingesting different dosages of caffeine (CAF) prior to plyometric jump training (PJT) on sport-related performance and physiological parameters in male basketball players. Twenty-four young athletes were randomly divided into 3 groups and performed 6 weeks of PJT while consuming 3 mg·kg
–1
of body mass caffeine (CAF3, n = 8), 6 mg·kg
–1
body mass caffeine (CAF6, n = 8) or placebo (PL; n = 8) one hour prior to each training session. Before and after the 6-week PJT, the players were evaluated for field-based basketball-specific performance measures (vertical jump, 20-m sprint, Illinois change of direction speed [CODS], and maximal strength) and lab-based physiological (aerobic capacity and anaerobic power) parameters. CAF3, CAF6, and PL groups demonstrated significant improvements in vertical jump (ES = 1.07, 1.45, and 1.1, respectively), 20-m sprint (ES = – 0.50, – 0.61, and – 0.36), change of direction performance (ES = – 1.22, – 1.26, and – 1.09), maximal strength (ES = 1.68, 2.29, and 1.17), maximum oxygen uptake (V̇O
2max
) (ES = 1.09, 1.59, and 0.92), and peak (ES = 1.82, 1.85, and 0.82) and average power output (ES = 1.39, 1.32, and 1.07) after 6 weeks of training. Comparative analysis of individual adaptive responses to training indicated that the CAF6 led to insignificantly greater effects in vertical jump (ES = 1.45), maximal strength (ES = 2.29), and V̇O
2max
(ES = 1.59) with lower residuals in individual changes and lower coefficient of variations (CV) in mean group changes. Regarding sprint and CODS performance, both experimental groups indicated similar changes, residuals in individual changes, and CVs in mean group changes. Overall, consuming 6 mg·kg
–1
body mass caffeine induces superior adaptations in aerobic fitness, anaerobic power, and sport-specific performance measures, with lower inter-individual variability in the adaptations and more homogenized changes over the training period.
Journal Article