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Dismantling the waste printed circuit boards (WPCBs) of obsolete mobile phones is essential for resource recycling and environmental protection. An automated WPCB disassembly equipment based on the hot-vibration process was designed and applied, with optimized process conditions of a heating temperature of 250 °C and an equipment amplitude of >3.66 mm. The dismantling rate for electronic components and metal shields was 98%, but disassembly of components with underfill was less effective. Both simulation and actual measurement results of the equipment’s thermal field showed that the temperature inside the disassembly bin was uniform, with a maximum temperature difference of 6–8 °C. The area of the low-temperature region accounted for approximately 5% of the total area. The acceleration ranged from 2.11 to 8.28 g when using the disassembly force model. This equipment and process can be applied to disassemble large quantities of WPCBs.

The electric field induced by the substrate could adjust the Schottky barrier from a p-type contact (WSe2/Gr) to an n-type contact (Gr/WSe2). Thus, it is more beneficial for the photo-thermionic electrons to transfer from graphene to WSe2 in Gr/WSe2.

Purpose: To construct deep learning (DL) models based on multicentre biparametric MRI (bpMRI) for the diagnosis of clinically significant prostate cancer (csPCa), and compare the performance of these models with that of Prostate Imaging Reporting and Data System (PI-RADS) assessment of expert-level radiologists based on multiparametric MRI (mpMRI).Methods: This study included 1861 consecutive men with mpMRI from seven hospitals, who underwent radical prostatectomy or biopsy. These patients were divided into training cohort (3 hospitals, 1216 patients) and external validation cohorts (4 hospitals, 645 patients). PI-RADS assessment was performed by expert-level radiologists. The DL models were constructed for the classifications between benign and malignant lesions (DL-BM), and between csPCa and non-csPCa (DL-CS). The integrated model combining a DL-CS model and PI-RADS (PIDL-CS) was constructed. The performance of the deep learning models and PIDL-CS were compared with those of PI-RADS.Results: In each external validation cohort, the area under receiver operating characteristic curve (AUC) values of DL-BM and DL-CS models were not significantly different from that of PI-RADS (Ps > 0.05), whereas the AUC of PIDL-CS was superior to that of PI-RADS (Ps < 0.05) except one external validation cohort (P > 0.05). The specificity of the PIDL-CS for the detection of csPCa was much more than that of PI-RADS (Ps < 0.05).Conclusion: Our proposed DL model can be a potential non-invasive auxiliary tool to predict csPCa. Further, PIDL-CS greatly increased the specificity in the detection of csPCa compared with PI-RADS assessment of expert-level radiologists, greatly reducing the unnecessary biopsies and helping radiologists achieve a precise diagnosis of csPCa.

Purpose This study aimed to develop deep learning (DL) models based on multicentre biparametric magnetic resonance imaging (bpMRI) for the diagnosis of clinically significant prostate cancer (csPCa) and compare the performance of these models with that of the Prostate Imaging and Reporting and Data System (PI-RADS) assessment by expert radiologists based on multiparametric MRI (mpMRI). Methods We included 1861 consecutive male patients who underwent radical prostatectomy or biopsy at seven hospitals with mpMRI. These patients were divided into the training (1216 patients in three hospitals) and external validation cohorts (645 patients in four hospitals). PI-RADS assessment was performed by expert radiologists. We developed DL models for the classification between benign and malignant lesions (DL-BM) and that between csPCa and non-csPCa (DL-CS). An integrated model combining PI-RADS and the DL-CS model, abbreviated as PIDL-CS, was developed. The performances of the DL models and PIDL-CS were compared with that of PI-RADS. Results In each external validation cohort, the area under the receiver operating characteristic curve (AUC) values of the DL-BM and DL-CS models were not significantly different from that of PI-RADS (P > 0.05), whereas the AUC of PIDL-CS was superior to that of PI-RADS (P P > 0.05). The specificity of PIDL-CS for the detection of csPCa was much higher than that of PI-RADS (P Conclusion Our proposed DL models can be a potential non-invasive auxiliary tool for predicting csPCa. Furthermore, PIDL-CS greatly increased the specificity of csPCa detection compared with PI-RADS assessment by expert radiologists, greatly reducing unnecessary biopsies and helping radiologists achieve a precise diagnosis of csPCa.

It was another difficult year for China in 2019. The Chinese economy and government revenue registered the lowest growth in nearly three decades. The employment situation has worsened and inflation driven by the surge in pork prices has reached its peak since 2012. Spending huge amounts of government money on social programmes has been China’s core coping strategy. This approach is however facing difficulties in localities with a smaller and less diverse revenue base. Social challenges will become even more manifest in 2020.

Graphene and its derivatives, due to their two-dimensional carbon nanostructures, have provided new opportunities to fortify organic dye-based photovoltaic and photocatalytic assemblies. In this article, we employed organic dyes Rhodamine B (RdB) and graphene oxide (GO) [or reduced graphene oxide (RGO)] to assemble the composite materials RdB–GO and RdB–RGO. It was found that both GO and RGO could strongly quench the fluorescence (FL) intensity of RdB. The mechanisms of FL quenching in both RdB–GO and RdB–RGO have been investigated by using femtosecond fluorescence up-conversion and transient absorption spectroscopy. When RdB was anchored on the GO (or RGO) surface, the solvent relaxation component 3.1 ps of pure RdB disappeared; instead, the ultrafast excited state electron transfer process (1–2ps) in RdB-GO and RdB-RGO was found and originated from the LUMO of RdB to the conduction band of GO (or RGO). We further reveal that the energy level change caused by GO reduction makes the energy levels of RGO closer to those of RdB, resulting in the electron transfer being more effective in RdB–RGO. Therefore, the RdB–RGO composite materials may have higher application values for dye-sensitized solar cells.

The United States’ fear of losing its technological edge to China is on the rise. The Trump administration has viewed China’s techno-industrial plans and policies as a national security threat. Recognising the reality that it cannot afford to have a Cold War or “cold peace” with the United States, China has shown willingness to make concessions, but only to a certain degree. The Trump administration’s growing hostility is unlikely to stop China from pursuing frontier technologies, which are a source of national competitiveness, security and pride for China as much as for the United States.

China had a bumpy year in 2018. The central government had to make a midyear adjustment with renewed emphasis on stabilising the economy and society prompted largely by the US-China trade war and a slew of domestic factors, such as the grieving middle class increasingly burdened by high living costs and growing household debts. By all signs, the year 2019 will be more difficult and a serious test is forthcoming for the Xi leadership.

The successful operation of dedicated detectors has brought us valuable information for understanding the central engine and the progenitor of gamma-ray bursts (GRBs). For instance, the giant X-ray and optical bumps found in some long-duration GRBs (e.g. GRBs 121027A and 111209A) imply that some extended central engine activities, such as the late X-ray flares, are likely due to the fall-back of progenitor envelope materials. Here we systemically search for long GRBs that consist of a giant X-ray or optical bump from the Swift GRB sample, and eventually we find 19 new possible candidates. The fall-back accretion model could well interpret the X-ray and optical bump for all candidates within a reasonable parameter space. Six candidates showing simultaneous bump signatures in both X-ray and optical observations, which could be well fitted at the same time when scaling down the X-ray flux into optical by one order of magnitude, are consistent with the standard $F_{\nu}\propto\nu^{1/3}$ synchrotron spectrum. The typical fall-back radius is distributed around $10^{10}\rm-10^{12}$ cm, which is consistent with the typical radius of a Wolf-Rayet star. The peak fall-back accretion rate is in the range of $\sim 10^{-11}-10^{-4}M_{\odot} \ \text{s} ^{-1}$ at time $\sim10^{2}- 10^{5}~\rm s$, which is relatively easy to fulfill as long as the progenitor's metallicity is not too high. Combined with the sample we found, future studies of the mass supply rate for the progenitors with different mass, metallicity, and angular momentum distribution would help us to better constrain the progenitor properties of long GRBs., Comment: accepted for publication by ApJ

Mutations in the potassium channel genes may be linked to the development of epilepsy and affect the blood potassium levels. Therefore, accurate determination of potassium in the blood will be critical to diagnose the cause of epilepsy. CE is a competent technique for the fast detection of multiple ions, but complicated matrices of a blood sample may cause significant variation of migration times and the peak shape. In this work, a procedure for rapid stabilization of the capillary inner surface through preflushing of a blood sample was employed. The process takes only 40 min for a capillary and then it can be used for more than 2 weeks. No pretreatment of the blood sample or other surface modification of the capillary is needed for the analysis. The RSDs of the migration time and peak area were reduced to 1.5 and 5.1% from 12.6 and 14.5%, respectively. The proposed method has been successfully applied to the determination of the potassium contents in the blood sample of patients with epilepsy at different stages. The recoveries of potassium ions in these blood samples are in a range from 86.5 to 104.5%.

Efficient interfacial light-electric interconversion in van der Waals heterostructures is critical for their optoelectronic applications. Using time-resolved terahertz spectroscopy and transient absorption spectroscopy, the charge transfer and the dynamical interlayer excitons were investigated in the heterostructures comprising monolayer WSe

Gamma-ray bursts (GRBs) at high redshifts are expected to be gravitationally lensed by objects of different mass scales. Besides a single recent claim, no lensed GRB has been detected so far by using the gamma-ray data only. In this paper, we suggest that the multi-band afterglow data might be an efficient way to search for lensed GRB events. Using the standard afterglow model we calculate the characteristics of the lensed afterglow lightcurves under the assumption of two popular analytic lens models: point mass and Singular Isothermal Sphere (SIS) model. In particular, when different lensed images cannot be resolved, their signals would be superimposed together with a given time delay. In this case, the X-ray afterglows are likely to contain several X-ray flares of similar width in linear scale and similar spectrum, and the optical afterglow lightcurve will show rebrightening signatures. Since the lightcurves from the image arriving later would be compressed and deformed in the logarithmic time scale, the larger time delay (i.e. the larger mass of the lens), the easier is to identify the lensing effect. We analyzed the archival data of optical afterglows and found one potential candidate of the lensed GRB (130831A) with time delay $\sim$500 s, however, observations of this event in gamma-ray and X-ray band seem not to support the lensing hypothesis. In the future, with the cooperation of the all-sky monitoring gamma-ray detectors and multi-band sky survey projects, our method proposed in this paper would be more efficient in searching for strongly lensed GRBs., Comment: Accepted for publication in ApJ

After decades of large-scale rural-to-urban migration, a massive wave of return migration has emerged in China, signalling China’s entry to a new stage of economic and social development. Behind the new trend are the economic take-off of China’s hinterland and the ageing of the first-generation migrant workers. While potentially a benign transformative force for rural China, return migration also risks becoming a way to “dump” ageing, unproductive or laid-off migrant workers in the vast countryside.

In September 2017, China released a list of universities to be developed into world-class universities or universities with world-class disciplines. As Xi Jinping’s most important initiative in higher education, the “Double World-Class” project is expected to advance Chinese universities in major international league tables. While the best Chinese universities aspire to equal the world’s best, deeper changes are needed in the governing of universities, allocating of research funding and fostering of conducive research environment.

Social policy scholars often take the view that welfare states can be classified into different types based on distinct political philosophies and stable institutional features. It is a challenge to position China in any such taxonomy, however. Using the volatile growth of educational expenditure in recent years as an example, this chapter suggests that China’s social policy in general, and educational policy in particular, has not evolved into a stable model. The tension between centralized mandates and decentralized financing generates greater irregularity than any existing theory can sufficiently explain. China often relies on top-down mobilization to achieve unfunded or underfunded policy mandates. Mobilization, however, cannot last long as it stresses and strains local governments. The alternation between mobilization and post-mobilization is highly disruptive for China’s welfare state building. Much more needs to be done to replace mobilization with a more regularized, sustainable, and equitable financing mechanism for education and other social programs.

China performed well in 2017 creating jobs, controlling inflation and promoting income growth. The Chinese Communist Party (CCP) had not been troubled by major disturbing incidents as in previous years. The single most important event in 2017 was the CCP’s 19th National Congress where “people’s ever-growing need for a better life versus unbalanced and inadequate development” was given emphasis. Addressing unbalanced development will likely be the CCP’s central task in the coming years.

The tension between mobilizing resources to meet education-related growth targets and regularizing educational funding for a more stable and sustainable growth is structurally rooted in China’s educational system, which features growth-oriented, centralized mandates and county-based, decentralized financing. It was manifested in 2012, when China experienced a ‘great leap’ in educational expenditure. Based on interviews and school-level data from a province in western China, this article suggests that the ‘great leap’ was real rather than fabricated. Local governments have demonstrated remarkable capacity in resource mobilization involving both formal and informal strategies. It also shows the scarring effects of too much mobilization. The ‘great leap’ has clearly stressed and strained local governments to the extent that there is clear evidence of policy non-compliance and greater irregularity in government funding for education in the aftermath.