Analysis and Prediction Model Reinforced UHPC Shrinkage Property

This paper explores the shrinkage of reinforced UHPC under high-temperature steam curing and natural curing conditions.The results are compared with the existing shrinkage prediction models.The results show that the maximum shrinkage strain of reinforced UHPC after steam curing is 164μεand gradually becomes zero.As for natural curing,the maximum shrinkage strain is 173μεand the value stabilizes on the 10th day after pouring.This indicated that steam curing can significantly reduce shrinkage time.Compared with the plain UHPC tested in the previous literature,the structural reinforcement can significantly inhibit the UHPC shrinkage and greatly reduce the risk of cracking due to shrinkage.By comparing the results in this paper with the existing models for predicting the shrinkage strain development,it is found that the formula recommended in the French UHPC structural and technical specification is suitable for the shrinkage curve in the present paper.

两性聚合物降滤失剂的合成及性能评价

以丙烯酰胺[AM]、2-丙烯酰胺基-2-甲基丙磺酸[AMPS]、烯丙基聚乙二醇[APEG-500]、丙烯酰氧乙基三甲基氯化铵（DAC]为单体，利用溶液聚合法制备了一种钻井液用两性聚合物降滤失剂。对降滤失剂进行了红外光谱表征，探讨了单体质量配比对钻井液降滤失性能的影响，评价了降滤失剂在淡水基浆、饱和盐水基浆、复合盐水基浆中的降滤失性能。研究结果表明：单体的最佳配比为m[AM]：m[AMPS]：m[APEG-500]：m[DAC]=65：25：5：5，降滤失剂在淡水基浆、饱和盐水基浆、复合盐水基浆的滤失量分别为7．5、9．6、10．1mL，最高使用温度可达200℃。

Review on Drug Regulatory Science Promoting COVID-19 Vaccine Development in China

Regulatory science is a discipline that uses comprehensive methods of natural science,social science,and humanities to provide support for administrative decision-making through the development of new tools,standards,and approaches to assess the safety,efficacy,quality,and performance of regulated products.During the pandemics induced by infectious diseases,such as H1N1 flu,severe acute respiratory syndrome(SARS),and Middle East respiratory syndrome(MERS),regulatory science strongly supported the development of drugs and vaccines to respond to the viruses.In particular,with the support of research on drug regulatory science,vaccines have played a major role in the prevention and control of coronavirus disease 2019(COVID-19).This review summarizes the overall state of the vaccine industry,research and development(R&D)of COVID-19 vaccines in China,and the general state of regulatory science and supervision for vaccines in China.Further,this review highlights how regulatory science has promoted the R&D of Chinese COVID-19 vaccines,with analyses from the aspects of nationallevel planning,relevant laws and regulations,technical guidelines,quality control platforms,and postmarketing supervision.Ultimately,this review provides a reference for the formulation of a vaccine development strategy in response to the current pandemic and the field of vaccine development in the post-pandemic era,as well as guidance on how to better respond to emerging and recurring infectious diseases that may occur in the future.

Emulsion Polymerization of P (MMA-AA-EA) and Its Demulsifying Performance in Water/Oil Emulsion

Stable water-in-oil emulsions are produced in oil exploitation and cause many environmental and operational issues.In this paper,a co-polymer demulsifier is reported in detail;an emulsion polymerization method is used to prepare nano-P(MMA-AA-EA)with MMA,AA and EA as the monomers,DVB as the cross-linker and APS as the initiator.The resulting products are characterized by FT-IR.Furthermore,the surface tension and particles size analysis is investigated.The results show that the surface tension reduction is 10.66 mN/m at 20?C when the concentration of co-polymer is 1000 ppm and the average size is 76.99 nm.Moreover,the HLB of polymer is discussed specifically by changing the amount of AA.With the increase of AA,the HLB value of the polymer is increased accordingly.Besides,the demulsification performance of the co-polymer is also evaluated at different synthesis and demulsification conditions.It is showed that the maximum demulsification efficiency is 96%at 70?C for 60 min.The optimum concentration of demulsifier is 400 ppm when the amounts of AA and DVB are 1.4 g and 0.1 g,respectively.At last,the process of demulsification is showed under a microscope;the coalescence process of water droplets is indicated under the action of the demulsifier.

High sensitivity of semimetal photodetection via Bose–Einstein condensation

The discovery of semiconductor has witnessed remarkable strides toward high performance of photodetectors attributed to its excellent carrier properties.However,semimetal,owning to the high carrier concentration and low carrier mobility compared to those of semiconductor,is generally considered unsuitable for photodetection.Herein,we demonstrate an outstanding photodetection in a layered semimetal titanium diselenide(TiSe_(2))in Bose-Einstein condensation(BEC)state.High sensitivity of semimetal photodetector is realized in the range of visible,infrared and terahertz bands.The noise equivalent power(NEP)has threefold improvement at the visible and infrared wavebands,and significant decrease by one order of magnitude in the terahertz frequencies via BEC phenomenon,attributed to the electrical parameter variation after condensation.The best NEP value in the terahertz frequency is comparable to that of commercial Si photodetector.Our results show another recipe to fabricate high performance of photodetection via semimetal except for semiconductor and pave the way to exploit macroscopic quantum phenomena for optoelectronics.

Plasmonic semiconductor nanogroove array enhanced broad spectral band millimetre and terahertz wave detection

High-performance uncooled millimnetre and terahertz wave detectors are required as a building block for a wide range of applications.The state-of-the art technologies,however,are plagued by low sensitivity,narrow spectral bandwidth,and complicated architecture.Here,we report semiconductor surface plasmon enhanced high-performance broadband millimetre and terahertz wave detectors which are based on nanogroove InSb array epitaxially grown on GaAs substrate for room temperature operation.By making a nanogroove array in the grown InSb layer,strong millimetre and terahertz wave surface plasmon polaritons can be generated at the InSb-air interfaces,which results in significant improvement in detecting performance.A noise equivalent power(NEP)of 2.2× 10^(-14)WHz^(-1/2) or a detectivity(D)of 2.7× 10^(12)cmHz^(1/2) W^(-1) at 1.75 mm(0.171 THz)is achieved at room temperature.By lowering the temperature to the thermoelectric cooling available 200 K,the corresponding NEP and D'of the nanogroove device can be improved to 3.8× 10^(-15)WHz^(-1/2) and 1.6× 10^(13) cm Hz^(-1/2) w^(-1),respectively.In addition,such a single device can perform broad spectral band detection from 0.9 mm(0.330 THz)to 9.4 mm(0.032 THz).Fast responses of 3.5μs and 780 ns are achieved at room temperature and 200 K,respectively.Such high-performance millimnetre and terahertz wave photodetectors are useful for wide applications such as high capacity communications,walk-through security,biological diagnosis,spectroscopy,and remote sensing.In addition,the integration of plasmonic semiconductor nanostructures paves a way for realizing high performance and multifunctional long-wavelength optoelectrical devices.

Antenna-assisted subwavelength metal–InGaAs–metal structure for sensitive and direct photodetection of millimeter and terahertz waves

Millimeter and terahertz wave photodetectors have a wide range of applications. However, the state-of-the-art techniques lag far behind the urgent demand due to the structure and performance limitations. Here, we report sensitive and direct millimeter and terahertz wave photodetection in compact InGaAs-based subwavelength ohmic metal–semiconductor–metal structures. The photoresponse originates from unidirectional transportation of nonequilibrium electrons induced by surface plasmon polaritons under irradiation. The detected quantum energies of electromagnetic waves are far below the bandgap of InGaAs, offering, to the best of our knowledge, a novel direct photoelectric conversion pathway for InGaAs beyond its bandgap limit. The achieved room temperature rise time and noise equivalent power of the detector are 45 μs and 20 pW · Hz^(-1∕2), respectively,at the 0.0375 THz(8 mm) wave. The detected wavelength is tunable by mounting different coupling antennas.Room temperature terahertz imaging of macroscopic samples at around 0.166 THz is also demonstrated. This work opens an avenue for sensitive and large-area uncooled millimeter and terahertz focal planar arrays.