The ultralow detection threshold,ultralow intrinsic background,and excellent energy resolution of ptype point-contact germanium detectors are important for rare-event searches,in particular for the detection of direct...The ultralow detection threshold,ultralow intrinsic background,and excellent energy resolution of ptype point-contact germanium detectors are important for rare-event searches,in particular for the detection of direct dark matter interactions,coherent elastic neutrino-nucleus scattering,and neutrinoless double beta decay.Anomalous bulk events with an extremely fast rise time are observed in the CDEX-1B detector.We report a method of extracting fast bulk events from bulk events using a pulse shape simulation and reconstructed source experiment signature.Calibration data and the distribution of X-rays generated by intrinsic radioactivity verified that the fast bulk experienced a single hit near the passivation layer.The performance of this germanium detector indicates that it is capable of single-hit bulk spatial resolution and thus provides a background removal technique.展开更多
Black phosphorus(BP)has been shown as a promising two-dimensional(2D)material for electronic devices owing to its high carrier mobility.To realize complementary electronic circuits with 2D materials,it is important to...Black phosphorus(BP)has been shown as a promising two-dimensional(2D)material for electronic devices owing to its high carrier mobility.To realize complementary electronic circuits with 2D materials,it is important to fabricate both n-type and p-type transistors with the same channel material.By engineering the contact region with copper(Cu)-doped BP,here we demonstrate an n-type carrier transport in BP field-effect transistors(FETs),which usually exhibit strongly p-type characteristics.Cu metal atoms are found to severely penetrate into the BP flakes,which forms interstitial Cu(Cuint)-doped edge contact and facilitates the electron transport in BP.Our BP FETs in backgated configuration exhibit n-type dominant characteristics with a high electron mobility of^138 cm^2 V^−1 s^−1 at room temperature.The Schottky barrier height for electrons is relatively low because of the edge contact between Cuint-doped BP and pristine BP channel.The contact doping of BP by highly mobile Cu atoms gives rise to n-type transport property of BP FETs.Furthermore,we demonstrate a p-n junction on the same BP flake with asymmetric contact.This strategy on contact engineering can be further extended to other 2D materials.展开更多
The Baumann Skin Typing System diagnoses patients as having one of 16 skin types based on their answers to a validated questionnaire [i] known as the Baumann Skin Type Indicator [ii]. The BSTI questionnaire has been t...The Baumann Skin Typing System diagnoses patients as having one of 16 skin types based on their answers to a validated questionnaire [i] known as the Baumann Skin Type Indicator [ii]. The BSTI questionnaire has been tested over the last decade on over 200,000 people of various ages and ethnicities in different geographic locations around the world. In this study, data were collected from 52,862 patients to compare skin type prevalence between those who presented to doctor’s offices and those who took the quiz without supervision online. The most common skin types varied only slightly between patients that took the quiz online and those that completed the questionnaire in their doctor’s office. This indicates that the prevalence of skin types seen in the doctor’s office is similar to that in the general population and that supervision is not necessary to get an accurate result on the BSTI. [iii] In addition, comparison of data gathered in China, Korea, and the US did not show a significant difference in skin type prevalence between Asian and Caucasian skin types. [iv] This study demonstrates that the English version of the BSTI is valid for English speaking patients online, and in doctors’ offices in the US, China and Korea.展开更多
基金supported by the National Key Research and Development Program of China(No.2017YFA0402203)the National Natural Science Foundation of China(No.11975162)the SPARK project of the research and innovation program of Sichuan University(No.2018SCUH0051)。
文摘The ultralow detection threshold,ultralow intrinsic background,and excellent energy resolution of ptype point-contact germanium detectors are important for rare-event searches,in particular for the detection of direct dark matter interactions,coherent elastic neutrino-nucleus scattering,and neutrinoless double beta decay.Anomalous bulk events with an extremely fast rise time are observed in the CDEX-1B detector.We report a method of extracting fast bulk events from bulk events using a pulse shape simulation and reconstructed source experiment signature.Calibration data and the distribution of X-rays generated by intrinsic radioactivity verified that the fast bulk experienced a single hit near the passivation layer.The performance of this germanium detector indicates that it is capable of single-hit bulk spatial resolution and thus provides a background removal technique.
基金supported by the Research Grant Council of Hong Kong(PolyU 152145/15E and 15305718)the Hong Kong Polytechnic University(G-YBPS,G-SB79 and 1-ZE6G)X.G.and Y.Z.thank Dr.Wei Lu for optimizing the JEOL JEM-2100F microscope.
文摘Black phosphorus(BP)has been shown as a promising two-dimensional(2D)material for electronic devices owing to its high carrier mobility.To realize complementary electronic circuits with 2D materials,it is important to fabricate both n-type and p-type transistors with the same channel material.By engineering the contact region with copper(Cu)-doped BP,here we demonstrate an n-type carrier transport in BP field-effect transistors(FETs),which usually exhibit strongly p-type characteristics.Cu metal atoms are found to severely penetrate into the BP flakes,which forms interstitial Cu(Cuint)-doped edge contact and facilitates the electron transport in BP.Our BP FETs in backgated configuration exhibit n-type dominant characteristics with a high electron mobility of^138 cm^2 V^−1 s^−1 at room temperature.The Schottky barrier height for electrons is relatively low because of the edge contact between Cuint-doped BP and pristine BP channel.The contact doping of BP by highly mobile Cu atoms gives rise to n-type transport property of BP FETs.Furthermore,we demonstrate a p-n junction on the same BP flake with asymmetric contact.This strategy on contact engineering can be further extended to other 2D materials.
文摘The Baumann Skin Typing System diagnoses patients as having one of 16 skin types based on their answers to a validated questionnaire [i] known as the Baumann Skin Type Indicator [ii]. The BSTI questionnaire has been tested over the last decade on over 200,000 people of various ages and ethnicities in different geographic locations around the world. In this study, data were collected from 52,862 patients to compare skin type prevalence between those who presented to doctor’s offices and those who took the quiz without supervision online. The most common skin types varied only slightly between patients that took the quiz online and those that completed the questionnaire in their doctor’s office. This indicates that the prevalence of skin types seen in the doctor’s office is similar to that in the general population and that supervision is not necessary to get an accurate result on the BSTI. [iii] In addition, comparison of data gathered in China, Korea, and the US did not show a significant difference in skin type prevalence between Asian and Caucasian skin types. [iv] This study demonstrates that the English version of the BSTI is valid for English speaking patients online, and in doctors’ offices in the US, China and Korea.
