An Evolutionary History of the Production Function

Xin, Yu,Han, Sung-Soo 명지대학교 북한연구소 2004 북한연구 Vol.7 No.-

My goal in this paper is to apply the evolutionary idea to study the history of the production function and argue that the economic theories about the production function have been developing gradually. There is a clear track along which the production function evolves from its most primitive prototype to its fancy mathematical form today in the more than 200 years history of the economic thoughts. Specifically, I focus my discussion on the origin and development of the Cobb-Douglas production function, which is the most ubiquitous function since its "birth" in 1928. The history of Cobb-Douglas production function is a history of the development of the related economic theories. It is necessary to put it in the historical background in order to avoid entangling oneself with piles of data without thinking about the theory for the measurement.

Effect of kaolin pretreatment on the structure and properties of metakaolin phosphate-based geopolymers

Xin Yu,Chengxin Ren,Wenlong Xu,Lina Xu,Qingbo Tian 한양대학교 청정에너지연구소 2024 Journal of Ceramic Processing Research Vol.25 No.1

This study focused on the preparation of metakaolin-based phosphate-activated geopolymers (MKPGs) using kaolin pretreatedat 950 °C for varying times as a precursor. It was found that kaolinite quickly transformed into amorphous metakaolin (MK)and then transitioned from a disordered phase to an ordered phase, resulting in precipitation of kyanite and mullite withincreasing calcination time. The formation of the kyanite phase had an adverse effect on geopolymerization, which causeda decrease in the strength of the MKPGs. The precipitation of the mullite phase hindered the geopolymerization reactionbetween phosphoric acid and MK, and the geopolymer failed to solidify. As the calcination time increased from 10 min to 60min, the compressive strength of the geopolymers increased and then decreased. The maximum strength of the geopolymerscreated from MK calcined for 30 min was 132.1 MPa.

Molecular evolutionary analysis reveals Arctic-like rabies viruses evolved and dispersed independently in North and South Asia

Xin Yu,Hongwei Zhu,Yongheng Bo,Youzhi Li,Jianlong Zhang,Linlin Jiang,Guozhong Chen,Xingxiao Zhang,Yongjun Wen 대한수의학회 2021 Journal of Veterinary Science Vol.22 No.1

Background: Arctic-like (AL) lineages of rabies viruses (RABVs) remains endemic in some Arctic and Asia countries. However, their evolutionary dynamics are largely unappreciated. Objectives: We attempted to estimate the evolutionary history, geographic origin and spread of the Arctic-related RABVs. Methods: Full length or partial sequences of the N and G genes were used to infer the evolutionary aspects of AL RABVs by Bayesian evolutionary analysis. Results: The most recent common ancestor (tMRCA) of the current Arctic and AL RABVs emerged in the 1830s and evolved independently after diversification. Population demographic analysis indicated that the viruses experienced gradual growth followed by a sudden decrease in its population size from the mid-1980s to approximately 2000. Genetic flow patterns among the regions reveal a high geographic correlation in AL RABVs transmission. Discrete phylogeography suggests that the geographic origin of the AL RABVs was in east Russia in approximately the 1830s. The ancestral AL RABV then diversified and immigrated to the countries in Northeast Asia, while the viruses in South Asia were dispersed to the neighboring regions from India. The N and G genes of RABVs in both clades sustained high levels of purifying selection, and the positive selection sites were mainly found on the C-terminus of the G gene. Conclusions: The current AL RABVs circulating in South and North Asia evolved and dispersed independently.

The Spillover Effects of Privatization on Efficiency and Income Inequality in China

Xinyu Li(Xinyu Li),Sunghwan Kim(Sunghwan Kim),Yongshang Liu(Yongshang Liu) The International Academy of Global Business and T 2023 The International Academy of Global Business and T Vol.19 No.1

Purpose - This study examines the spatial and inter-temporal spillover effects of privatization on the corporate efficiency and regional income inequality of Chinese state-owned enterprises (SOEs). Design/Methodology/Approach - The spatial Durbin model (SDM) is used in regressions to examine the spatial and inter-temporal spillover effects of the privatization of SOEs on improving the efficiency and income inequality of Chinese firms across regions. A panel dataset of Chinese-listed firms from 2008 to 2018 is used. The stochastic frontier analysis method is applied in estimating corporate efficiency. Findings - First, the privatization of Chinese SOEs increased their efficiency, but exacerbated their income inequality. Second, the globalization activities after the privatization of Chinese SOEs increased their efficiency, but exacerbated their income inequality. Specifically, exports decrease income inequality, while outward foreign direct investment or OFDI has an inverse U-shaped effect on income inequality. Third, the privatization improved overall corporate efficiency within the province and that of neighboring provinces. Fourth, the Chinese SOE firms after privatization aggravated income equality within the province and that of neighboring provinces. Research Implications - In general, the results of this study indicate that the privatization of SOEs and the globalization activities after the privatization have improved the efficiency of Chinese firms, but worsened income equality within the province and that of neighboring provinces. Therefore, there is a strong need for governmental policies to cure income equality in provinces around the location of privarized firms.

Comparison of Clinical and Radiographic Outcomes Between Transforaminal Endoscopic Lumbar Discectomy and Microdiscectomy: A Follow-up Exceeding 5 Years

Xinyu Yang,Shijun Zhang,Junxiao Su,Sai Guo,Yakubu Ibrahim,Kai Zhang,Yonghao Tian,Lianlei Wang,Suomao Yuan,Xinyu Liu 대한척추신경외과학회 2024 Neurospine Vol.21 No.1

Objective: To compare the long-term clinical and radiographic outcomes of transforaminal endoscopic lumbar discectomy (TELD) versus microdiscectomy (MD). Methods: The data of 154 patients with lumbar disc herniation (LDH) who underwent TELD (n = 89) or MD (n = 65) were retrospectively analyzed. The patients’ clinical outcomes were evaluated using visual analogue scales for leg and low back pain, the Japanese Orthopaedic Association (JOA) score, and the Oswestry Disability Index (ODI). The evolution of radiographic manifestations was observed during follow-up. Potential risk factors for a poor clinical outcome were investigated. Results: During a mean follow-up of 5.5 years (range, 5–7 years), the recurrence rate was 4.49% in the TELD group and 1.54% in the MD group. All scores significantly improved from preoperatively to postoperatively in both groups (p < 0.01). The improvement in the ODI and JOA scores was significantly greater in the TELD than MD group (p < 0.05). Forty-seven patients (52.8%) in the TELD group and 32 (49.2%) in the MD group had Modic changes before surgery, most of which showed no changes at the last follow-up. The degeneration grades of 292 discs (71.0%) were unchanged at the last follow-up, while 86 (20.9%) showed improvement, mostly at the upper adjacent segment. No significant difference was observed in the intervertebral height index or paraspinal muscle-disc ratio. Conclusion: Both TELD and MD provide generally satisfactory long-term clinical outcomes for patients with LDH. TELD can be used as a reliable alternative to MD with less surgical trauma. Modic type II changes, decreased preoperative intervertebral height, and a high body mass index are predictors of a poor prognosis. Objective: To compare the long-term clinical and radiographic outcomes of transforaminal endoscopic lumbar discectomy (TELD) versus microdiscectomy (MD). Methods: The data of 154 patients with lumbar disc herniation (LDH) who underwent TELD (n = 89) or MD (n = 65) were retrospectively analyzed. The patients’ clinical outcomes were evaluated using visual analogue scales for leg and low back pain, the Japanese Orthopaedic Association (JOA) score, and the Oswestry Disability Index (ODI). The evolution of radiographic manifestations was observed during follow-up. Potential risk factors for a poor clinical outcome were investigated. Results: During a mean follow-up of 5.5 years (range, 5–7 years), the recurrence rate was 4.49% in the TELD group and 1.54% in the MD group. All scores significantly improved from preoperatively to postoperatively in both groups (p < 0.01). The improvement in the ODI and JOA scores was significantly greater in the TELD than MD group (p < 0.05). Forty-seven patients (52.8%) in the TELD group and 32 (49.2%) in the MD group had Modic changes before surgery, most of which showed no changes at the last follow-up. The degeneration grades of 292 discs (71.0%) were unchanged at the last follow-up, while 86 (20.9%) showed improvement, mostly at the upper adjacent segment. No significant difference was observed in the intervertebral height index or paraspinal muscle-disc ratio.

Xylazole inhibits NO-cGMP pathway in fetal rat nerve cells

Xinyu Wang,Yue Wu,Lin Liu,Hui Bai,Zhiheng Zhang,Mingchao Zhao,Tianwen Ma,Xiaopeng Song,Lina Jia,Liangyu Lv,Yue Yu,Xinyu Xu,Hong Chen,Li Gao 대한수의학회 2022 Journal of Veterinary Science Vol.23 No.1

Background: Xylazole (Xyl) is a veterinary anesthetic that is structurally and functionally similar to xylazine. However, the effects of Xyl in vitro remain unknown. Objectives: This study aimed to investigate the anesthetic mechanism of Xyl using fetal rat nerve cells treated with Xyl. Methods: Fetal rat nerve cells cultured for seven days were treated with 10, 20, 30, and 40 μg/ mL Xyl for 0, 5, 10, 15, 20, 25, 30, 45, 60, 90, and 120 min. Variations of amino acid neurotransmitters (AANTs), Nitric oxide-Cyclic GMP (NO-cGMP) signaling pathway, and ATPase were evaluated. Results: Xyl decreased the levels of cGMP and NO in nerve cells. Furthermore, Xyl affected the AANT content and Na+-K+-ATPase and Ca2+-Mg2+-ATPase activity in nerve cells. These findings suggested that Xyl inhibited the NO-cGMP signaling pathway in nerve cells in vitro. Conclusions: This study provided new evidence that the anesthetic and analgesic effects of Xyl are related to the inhibition of the NO-cGMP signaling pathway.

First principles study of monolayer Sb2S2Te and a mathematical model of a thin-film thermoelectric generator with maximum power point tracing

Liu Xinyu,Yuan Shaoheng,Gu Bo,Chen Qiongxuan,Pu Xinyu,Zhang Jiangtao 한국물리학회 2022 Current Applied Physics Vol.36 No.-

The result of the structural, electronic and thermoelectric performance of monolayer Sb2S2Te, which is a brannew material, is calculated by using the method of full-potential linearized augmented plane-wave (FP-LAPW), and the exchange-correlation potential selected in this paper is generalized gradient approximation (GGA) scheme. There are no negative frequencies in the calculated phonon spectra, which demonstrates that dynamics of monolayer Sb2S2Te is stable in theory. The average value of lattice thermal conductivity (κl) is smaller than that of other thermoelectric (TE) materials, and monolayer Sb2S2Te has larger figure of merit (ZT) comparing with other well-known materials. According to the TE parameters (Seebeck coefficient S, electrical conductivity σ, electronic thermal conductivity κe and lattice thermal conductivity κl) of monolayer Sb2S2Te, an idealized model of thermoelectric generator (TEG) and a realistic model of maximum power point tracking (MPPT) are built. In addition, this paper studies the influence of different temperature zones, different temperature differences, cross sectional area, height and the number of P–N junction on output power and conversion efficiency of TEG. The results of physical calculation and simulation models show that the conversion efficiency of TEG of monolayer Sb2S2Te is larger than or close to that of other well-known materials, and the tracking accuracy of MPPT proposed in this paper is higher than or close to that of other researches.

A novel hydrothermal releasing synthesis of modified SiO2 material and its application in phenol removal process

Xinyu Yang,Xiaoyao Liu,Wenjing Tang,Yajun Gao,Huijuan Ni,Jianbin Zhang 한국화학공학회 2017 Korean Journal of Chemical Engineering Vol.34 No.3

A modified SiO2 material (MSM) was successfully synthesized by using Na2SiO3 and a novel CO2SM in the presence of CTAB through an innovative hydrothermal releasing treatment protocol. The MSM was systemically characterized using several techniques, including N2 adsorption-desorption isotherm, thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD). The CO2SM as a platform for CO2 capturing and releasing can be reversibly used for multiple cycles without significant loss of capabilities. The optimum conditions for the preparation of MSM were identified as follows: Na2SiO3 concentration, 0.2mol/L; hydrothermal temperature, 120 oC; CO2SM dosage, 6 g; CTAB concentration, 24 g/L, reaction time, 12 h. Additionally, the MSM exhibited high efficiency for the removal of phenol from aqueous solution: it showed a phenol adsorption capacity of 91.29mg/g when shaken with the aqueous phenol solution at 180 rpm for 1 h at 25 oC.

An Empirical Study on the Impact of Trade Facilitation on China's Export Trade

Xinyu ZHAO,Fan ZHANG 한국유통과학회 2020 The Journal of Industrial Distribution & Business( Vol.11 No.9

Purpose: Many studies show that promoting the development of trade facilitation has a positive role in stimulating the country's foreign trade. Therefore, it is of great practical significance to study the development level of trade facilitation for China's export trade. Research design, data and methodology:This study analyzes the growth trend of China's export trade volume in 2009-2019, the characteristics of China's export trade market according to the top 18 major exporting countries in 2017-2018, the structure of export commodities to understand China's economic development level, and compares the total amount of trade exported to all uses this to measure the level of trade development. On this basis, this paper selects the 2011-2018 Trade Facilitation Index and C continents to study the development trend. Based on the theory of trade facilitation, this paper constructs the Trade Facilitation Index, and hina's export trade volume for empirical research. Results: The results show that trade facilitation has a positive and significant impact on the development of China's export trade. Conclusions: Based on the analysis of the actual situations and empirical results, this paper puts forward some suggestions to promote the level of trade facilitation in order to promote the development of import and export trade

Research on the Composite Control Strategy of the Doubly Fed Induction Generator Grid Side Converter

Xinyu Liu,Ke Bai,Guoquan Wang 보안공학연구지원센터 2016 International Journal of Hybrid Information Techno Vol.9 No.10

Aiming at the existing problems of the DFIG grid side converter, this paper studies its control technology and proposes a composite control strategy which includes a terminal sliding mode variable structure control of the current inner-loop and a PI controller of the voltage outer-loop in grid side converter. The simulation results show that the control strategy proposed in this paper can achieve better control of the inverter output voltage and input current. What's more important, this method can not only reduce the adverse effects on the grid side converter due to parameter variations and other factors, but also increases the robustness of the system. It has important actual significance and practical application value.