The Rise of Robots in China Cheng, Hong; Jia, Ruixue; Li, Dandan ...
The Journal of economic perspectives,
04/2019, Letnik:
33, Številka:
2
Journal Article
Recenzirano
Odprti dostop
China is the world's largest user of industrial robots. In 2016, sales of industrial robots in China reached 87,000 units, accounting for around 30 percent of the global market. To put this number in ...perspective, robot sales in all of Europe and the Americas in 2016 reached 97,300 units (according to data from the International Federation of Robotics). Between 2005 and 2016, the operational stock of industrial robots in China increased at an annual average rate of 38 percent. In this paper, we describe the adoption of robots by China's manufacturers using both aggregate industry-level and firm-level data, and we provide possible explanations from both the supply and demand sides for why robot use has risen so quickly in China. A key contribution of this paper is that we have collected some of the world's first data on firms' robot adoption behaviors with our China Employer-Employee Survey (CEES), which contains the first firm-level data that is representative of the entire Chinese manufacturing sector.
Excitonic effects caused by Coulomb interactions between electrons and holes play subtle and significant roles on photocatalysis, yet have been long ignored. Herein, porphyrinic covalent organic ...frameworks (COFs, specifically DhaTph-M), in the absence or presence of different metals in porphyrin centers, have been shown as ideal models to regulate excitonic effects. Remarkably, the incorporation of Zn2+ in the COF facilitates the conversion of singlet to triplet excitons, whereas the Ni2+ introduction promotes the dissociation of excitons to hot carriers under photoexcitation. Accordingly, the discriminative excitonic behavior of DhaTph-Zn and DhaTph-Ni enables the activation of O2 to 1O2 and O2 •–, respectively, under visible light irradiation, resulting in distinctly different activity and selectivity in photocatalytic terpinene oxidation. Benefiting from these results, DhaTph-Ni exhibits excellent photocatalytic activity in O2 •–-engaged hydroxylation of boronic acid, while DhaTph-Zn possesses superior performance in 1O2-mediated selective oxidation of organic sulfides. This work provides in-depth insights into molecular oxygen activation and opens an avenue to the regulation of excitonic effects based on COFs.
Small‐molecule organic fluorophores, spectrally active in the 900–1700 nm region, with tunable wavelength and sensing properties are sought‐after for in vivo optical imaging and biosensing. A panel ...of fluorescent dyes (CX) has been developed to meet this challenge. CX dyes exhibit the wavelength tunability of cyanine dyes and have a rigidified polymethine chain to guarantee their stability. They are chemo‐ and photo‐stable in an aqueous environment and have tunable optical properties with maximal absorbing/emitting wavelength at 1089/1140 nm. They show great potential in high‐contrast in vivo bioimaging and multicolor detection with negligible optical cross talk. Förster resonance energy transfer (FRET) between CX dyes was demonstrated in deep tissue, providing an approach for monitoring drug‐induced hepatotoxicity by detection of OONO−. This report presents a series of NIR‐II dyes with promising spectroscopic properties for high‐contrast bioimaging and multiplexed biosensing.
A series of NIR‐II dyes (CX) with promising spectroscopic properties has been developed and used for in vivo multicolor imaging at a tissue depth of up to 4 mm. These were used to develop a FRET‐based fluorescence probe, which was successfully applied to the in vivo detection of drug‐induced hepatotoxicity. The regulation of NIR‐II fluorescence via FRET could serve as a general strategy for future NIR‐II fluorescent sensor design.
In this review, we provide an overview of recent progress achieved in MOF-based photocatalysts for CO2 reduction on the basis of the reduced products. Diverse modification techniques for improving ...relevant photocatalytic performance and the corresponding structure-activity relationships are highlighted. Particular emphasis is placed on the role of CO2 capture capacity for the photocatalytic CO2 reduction performance over MOF-based materials. Furthermore, the opportunities, challenges and future prospects of the application of MOF-based materials for photocatalytic CO2 conversion have also been highlighted.
Display omitted
•An overview of research advances in photocatalytic CO2 reduction over MOF-based materials.•Key role of CO2 capture capacity in CO2 photoreduction performance over MOF-based materials.•The challenges and opportunities of MOF-based materials for photocatalytic CO2 reduction.
Photocatalytic reduction of carbon dioxide (CO2) into high value-added chemicals using clean and renewable solar energy is a very promising pathway to address energy and environmental issues. Recently, metal-organic frameworks (MOFs) have been intensively exploited in photocatalytic CO2 reduction owing to their promising CO2 capture capability, photochemical and textural properties. In this review, we provide an overview of recent progress achieved in MOF-based photocatalysts for CO2 reduction on the basis of the reduced products, including photocatalytic conversion of CO2 into CO and the other organic chemicals (formic acid, methanol and methane). Diverse modification techniques for improving relevant photocatalytic performance and the corresponding structure-activity relationships are highlighted. Particular emphasis is placed on the role of CO2 capture capacity for the photocatalytic CO2 reduction performance over MOF-based materials. Furthermore, the opportunities, challenges and future prospects of the application of MOF-based materials for photocatalytic CO2 conversion are given, aiming at rational design of more creative MOF-based photocatalytic systems for CO2 utilization with a green and sustainable strategy.
Probiotics have been widely used in the treatment of intestinal diseases, but the effect of probiotics on female reproductive tract health is still controversial.
Lactobacillus
is the most abundant ...microorganism in the vagina, which is related to the vaginal mucosal barrier.
Lactobacillus
adheres to the vaginal epithelium and can competitively antagonize the colonization of pathogens. The factors produced by
Lactobacillus
, such as bacteriocin and hydrogen peroxide (H
2
O
2
), can inhibit the growth of pathogenic microorganisms and maintain the low pH environment of the vagina. Probiotics play an important role in maintaining the stability of vaginal microenvironment, improving immune defense and blocking the progression of cervical cancer. We review the research progress of probiotics represented by
Lactobacillus
in gynecological diseases such as human papilloma virus (HPV) infection, bacterial vaginosis (BV) and Genitourinary Syndrome of Menopause (GSM), so as to provide basis for further exerting the role of probiotics in women’s health.
Filamentous fungi have been of great interest because of their excellent ability as cell factories to manufacture useful products for human beings. The development of genetic transformation ...techniques is a precondition that enables scientists to target and modify genes efficiently and may reveal the function of target genes. The method to deliver foreign nucleic acid into cells is the sticking point for fungal genome modification. Up to date, there are some general methods of genetic transformation for fungi, including protoplast-mediated transformation, Agrobacterium-mediated transformation, electroporation, biolistic method and shock-wave-mediated transformation. This article reviews basic protocols and principles of these transformation methods, as well as their advantages and disadvantages.
The contrast and sensitivity of in vivo fluorescence imaging has been revolutionized by molecular fluorophores operating in the second near-infrared window (NIR-II; 1000-1700 nm), but an ongoing ...challenge is the solvatochromism-caused quenching in aqueous solution for the long-wavelength absorbing fluorophores. Herein, we develop a series of anti-quenching pentamethine cyanine fluorophores that significantly overcome the severe solvatochromism, thus affording stable absorption/emission beyond 1000 nm with up to ~ 44-fold enhanced brightness and superior photostability in aqueous solution. These advantages allow for deep optical penetration (8 mm) as well as high-contrast and highly-stable lymphatic imaging superior to clinical-approved indocyanine green. Additionally, these fluorophores exhibit pH-responsive fluorescence, allowing for noninvasive ratiometric fluorescence imaging and quantification of gastric pH in vivo. The results demonstrate reliable accuracy in tissue as deep as 4 mm, comparable to standard pH electrode method. This work unlocks the potential of anti-quenching pentamethine cyanines for NIR-II biological applications.
Interfacial electron transfer between cocatalyst and photosensitizer is key in heterogeneous photocatalysis, yet the underlying mechanism remains subtle and unclear. Surfactant coated on the metal ...cocatalysts, greatly modulating the microenvironment of catalytic sites, is largely ignored. Herein, a series of Pt co‐catalysts with modulated microenvironments, including polyvinylpyrrolidone (PVP) capped Pt nanoparticles (denoted as PtPVP), Pt with partially removed PVP (PtrPVP), and clean Pt without PVP (Pt), were encapsulated into a metal–organic framework (MOF), UiO‐66‐NH2, to afford PtPVP@UiO‐66‐NH2, PtrPVP@UiO‐66‐NH2, and Pt@UiO‐66‐NH2, respectively, for photocatalytic hydrogen production. The PVP appears to have a negative influence on the interfacial electron transfer between Pt and the MOF. Compared with PtPVP@UiO‐66‐NH2, the removal of interfacial PVP improves the sluggish kinetics of electron transfer, boosting photocatalytic hydrogen production.
Pt co‐catalysts with modulated microenvironments, including polyvinylpyrrolidone (PVP) capped Pt nanoparticles (denoted as PtPVP), Pt with partially removed PVP (PtrPVP), and clean Pt without PVP (Pt), are encapsulated in a metal–organic framework (MOF). Systemic investigations suggest that the PVP presents negative influence on the interfacial electron transfer between Pt and the MOF, and the PVP removal greatly boosts photocatalysis.
•We formulated a methodology framework to establish data-driven models for effective groundwater management.•We verified the applicability of data-driven models across tempo-spatial scale.•We ...demonstrated the tempo-spatial distribution of changes in groundwater level by using O2S2 method.
The overexploitation of groundwater resource and its delicacy management has gained increasing attentions in recent years worldwide because of causing a series of serious environmental and geological problems. Currently, accurately predicting the groundwater level (GWL) is an important issue in effective groundwater management across scales. In the present study, three popularly-used data-driven models, which are an autoregressive integrated moving average (ARIMA), a back-propagation artificial neural network (BP-ANN) and long short-term memory (LSTM), were established in five zones with different hydrogeological properties to explore the model’s accuracy in predicting the GWL at monthly and daily scales in a Northern Plain in China. The developed models were evaluated by both the Nash-Sutcliffe efficiency coefficient (NSE) and root mean square error (RMSE). The results indicate that the performance of the LSTM model is best at monthly time scales with the NSEs greater than 0.76 and RMSEs smaller than 1.15 m in each zone during the training period and demonstrate a good performance at daily time scales with the NSEs greater than 0.9 and the RMSEs smaller than 0.55 m at a local area. Meanwhile, the tempo-spatial distribution of the probability of drawdowns from the LSTM model was estimated by using the object-oriented spatial statistical (O2S2) method. The results show that cumulative drawdowns greater than 10 m are mainly concentrated in water source areas, with probabilities over 0.7 from 2003 to 2010 and declining to less than 0.3 from 2011 to 2014. The GWL rose generally in the study area from 2015 to 2018, but the probability of a drawdown with more than 5 m exceeded 0.8 in Zone V because of continuing groundwater exploitation. This study formulates a framework on developing effective data-driven models for predicting the GWL across scales which have the potential to aid groundwater management.
PDF
