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By treating users' interactions as a user-item graph, graph learning models have been widely deployed in Collaborative Filtering(CF) based recommendation. Recently, researchers have introduced Graph Contrastive Learning(GCL) techniques into CF to alleviate the sparse supervision issue, which first constructs contrastive views by data augmentations and then provides self-supervised signals by maximizing the mutual information between contrastive views. Despite the effectiveness, we argue that current GCL-based recommendation models are still limited as current data augmentation techniques, either structure augmentation or feature augmentation. First, structure augmentation randomly dropout nodes or edges, which is easy to destroy the intrinsic nature of the user-item graph. Second, feature augmentation imposes the same scale noise augmentation on each node, which neglects the unique characteristics of nodes on the graph. To tackle the above limitations, we propose a novel Variational Graph Generative-Contrastive Learning(VGCL) framework for recommendation. Specifically, we leverage variational graph reconstruction to estimate a Gaussian distribution of each node, then generate multiple contrastive views through multiple samplings from the estimated distributions, which builds a bridge between generative and contrastive learning. Besides, the estimated variances are tailored to each node, which regulates the scale of contrastive loss for each node on optimization. Considering the similarity of the estimated distributions, we propose a cluster-aware twofold contrastive learning, a node-level to encourage consistency of a node's contrastive views and a cluster-level to encourage consistency of nodes in a cluster. Finally, extensive experimental results on three public datasets clearly demonstrate the effectiveness of the proposed model., This paper is accepted to SIGIR 2023. Code is avaliable: https://github.com/yimutianyang/SIGIR23-VGCL

Long-term conventional tillage leads to soil compaction and formation of a plough layer, which affects soil physical properties, transport of water, and growth of crop roots toward deeper soil, resulting in soil degradation and a decline in crop productivity. Long-term sub-soiling tillage has proven to be an effective measure for remediating the plough layer and improving the structure and physical properties of the soil. In this study, we experimentally investigated the effects of long-term sub-soiling tillage in an arid region of Henan Province, China, along a deep soil (0–100 cm) profile over 8 years of sub-soiling tillage at a depth of 30 cm and compared the results against conventional tillage at a depth of 15 cm. We measured soil pore distributions of macropores (> 1 mm in diameter), mesopores (0.16–1.0 mm), and total pores (> 0.16 mm) measured by X-ray computed tomography (CT), soil total porosity (ϕ) and > 0.16 mm equivalent porosity measured by conventional methods, soil bulk density (ρs), soil organic carbon content (SOC), the proportion of macroaggregates (> 0.25 mm) (PMA), soil field moisture capacity (fc), available moisture content, and saturated hydraulic conductivity (Ksat). The results indicate that long-term sub-soiling tillage increased soil pore numbers at 0–35 cm depth (macropores, mesopores, and total pores), improved pore shape, and significantly increased porosity at 0–20 cm depth (macropores, mesopores, and total pores; p < 0.05) compared to conventional tillage. In addition, ϕ and > 0.16 mm equivalent porosity were increased by 10.4 and 87.1% at depths of 0–60 cm under sub-soiling tillage, respectively. SOC (0–55 cm depth), fc (0–45 cm depth), available moisture content (0–40 cm depth), Ksat (0–40 cm depth), and PMA (0–50 cm depth) were increased by 16.7, 14.3, 23.8, 471.5, and 98.3%, respectively, and ρs (0–60 cm depth) was reduced by 8.6%. Observed correlations between SOC, soil pore parameters, and soil physical properties suggest that soil pore parameters and soil physical properties can be improved by increasing SOC. These correlations are stronger under sub-soiling than that under conventional tillage. Therefore, sub-soiling is an effective technique for improving soil pore characteristics and physical properties while preventing soil degradation.

Intensive farming leads to soil degradation, and poses a serious threat to agricultural yield sustainability and soil ecology. Superabsorbent polymer (SAP) and organic manure (OM) are amendments that can remediate the soil, and improve soil structure and soil pore characteristics, thereby enhancing soil quality and promoting crop growth. These benefits may be enhanced through long-term continuous application of the amendments. X-ray computed tomography (CT) was used to determine the number, connectivity, and locations of pores (160–1,000 μm, >1,000 µm) in the soil at depths of 0–100 cm. Soil organic carbon content, proportion of water-stable macroaggregates (>0.25 mm) (WSM), soil bulk density, field water capacity, available water content, wilting point content, and saturated hydraulic conductivity were also determined. Compared to the control, long-term SAP and OM treatments significantly increased the number of 160–1,000 µm and >1,000 µm soil pores (5–20 cm depths), >1,000 µm and >160 µm soil porosity (at 0–20 cm depths), total organic carbon (10–20 cm and 40–50 cm), field water capacity (0–20 cm), available water content (0–20 cm), wilting point (10–30 cm), saturated water content (10–70 cm), saturated hydraulic conductivity (0–90 cm), and WSM (0–30 cm and 40–50 cm) while decreasing the soil bulk density (0–70 cm). Compared to OM, SAP had greater beneficial effects on the total organic carbon, soil field water capacity, available water content, saturated water content, saturated hydraulic conductivity, and WSM in soil at 0–20 cm depth. The improvements to soil quality resulted in an increase in the yields of wheat and maize. Therefore, although SAP and OM were both effective at improving soil properties and increasing the economic yield of wheat and maize, the effectiveness of SAP was greater than that of OM.

In obesity, macrophages and other immune cells accumulate in organs affected by insulin, leading to chronic inflammation and insulin resistance. 4-Hydroxyisoleucine (4-HIL) is a non-protein amino acid found in fenugreek seeds. 4-HIL enhances insulin sensitivity, but its mechanism is still unclear. In this study, 4-HIL intervention reduced weight gain, liver steatosis, and dyslipidemia; moreover, it increased systemic insulin sensitivity and improved insulin resistance in mice. Importantly, after administration, the accumulation of M1 like CD11c+ macrophages and inflammation in the liver and adipose tissue were reduced in the mice. 4-HIL also reduced the proportion of CD11c+ macrophages among bone marrow-derived macrophages, which were induced in vitro. These observations demonstrate a new role of 4-HIL in insulin resistance in hepatocytes and adipocytes. 4-HIL inhibits obesity-related insulin resistance by reducing inflammation and regulating the state of M1/M2 macrophages.

Super absorbent polymer (SAP) and organic manure (OM) may improve soil structure and change soil organic carbon (SOC) composition and agroecosystem functioning. However, the understanding of the effects of SAP and OM on SOC composition, specifically in deeper soil layers, is still not clear. The objectives of this study were to examine the effects of long-term application of SAP and OM (8 years) on changes in SOC and soil structure down to a soil depth of 100 cm. Therefore, in order to investigate the stability of soil structure and the distribution of organic carbon at different soil depths (0-10 cm, 10-20 cm,…, 90-100 cm) under long-term application of SAP, OM, and a control treatment, soil structure and soil organic carbon content were analyzed in mixed soil samples and undisturbed soil samples. The results indicated that with depth, the proportion of large aggregates (0.5-2.0 mm) decreased gradually, while the proportion of small aggregates (0.5 mm soil aggregates in the 0-30 cm and 40-60 cm soil layers (P < 0.05) and 0.25-0.5 mm in the 0-50 cm soil layer (P < 0.05), and while the OM treatment had the same effect in the 0-30 cm soil layer (P < 0.05). The total organic carbon content (TOC) and labile organic carbon content (LOC) of bulk soil increased (0-20 cm) initially with depth, and then decreased (20-70 cm) approximately. In the 0-50 cm soil layer, the TOC and LOC under SAP treatment were higher than those under OM treatment. The SAP treatment was more beneficial to the increase of the TOC and LOC of 0.5-2.0 mm and 0.25-0.5 mm aggregates in the 10-40 cm soil layer compared with the control and OM treatment (P < 0.05). The SAP treatment was also more beneficial in increasing the contribution rate of organic carbon (CROC) in> 0.5 mm aggregates in 0-40 cm soil depth, while the OM treatment was more beneficial in increasing the CROC of > 0.5 mm aggregates in 0-30 cm soil depth. The SAP treatment improved the stability of the soil structure in 0-30 cm and 40-60 cm depths, and the OM treatment had the same effect in the 0-30 cm depth. Compared with the control and OM treatments, SAP treatment has shown to be the most beneficial in improving soil structure and increasing organic carbon content.

Additional file 1: Supplementary Table 1. False-Positive Report Probability Values for Associations Between the Risk of rheumatoid arthritis and the Frequency of Variants and Model of FCRL Gene in the Chinese Han population.

Antitumor transcription activator NFE2L1, with the functions to regulate redox homeostasis, protein turnover, and material metabolism, plays an important role in embryonic development and specialization of tissue and organ functions. Deficiency of NFE2L1 gene in different regions yields distinct phenotypes, suggesting that NFE2L1 may have a transcription factor-independent function. Here we originally discovered the non-transcription factor activity of NFE2L1 by constructing a truncated protein-NFE2L1ΔC without 152 aa at the C-terminus which lost the transcription factor activity. The regulation of NFE2L1 on redox homeostasis, proteasome function, and immune response mainly depends on its transcription activator function in nucleus, while the regulation on metabolism, ribosome function, and canceration is germanely to its non-transcription factor activity in cytoplasm. Surprisingly, the results indicated the tumor suppressive effect of NFE2L1 by repression of Wnt/β-catenin signaling in a non-transcription factor manner, indicating the potential value of NFE2L1 as a therapeutic target in clinical cancer treatment independent of its transcription factor activity. Our observations reveal the non-transcription factor activity of NFE2L1 for the first time, and lay foundation for the basic and applied research of NFE2L1.

A novel carrier stored (CS) SOI lateral insulated gate bipolar transistor (LIGBT) with ultralow on-state voltage drop ( ${V}_{ \mathrm{\scriptscriptstyle ON}}$ ) and high current capability is proposed and its electronic performance is investigated by simulation. The device features the CS layer and the trigate (TG) structure, named TGCS LIGBT. The CS effect in the on-state delivers an ultralow ${V}_{ \mathrm{\scriptscriptstyle ON}}$ . The TG is employed to increase the channel density and modulate the current distribution, further reducing the ${V}_{ \mathrm{\scriptscriptstyle ON}}$ and achieving high current capability. Moreover, TG assists in depleting the highly doped CS layer, which enhances the conductivity modulation and maintains high breakdown voltage. The extended P+ in the comb-shaped P+ region provides a low-resistance hole current path, and thus enhances the latch-up immunity. At the same turn-off loss, the TGCS LIGBT reduces the ${V}_{ \mathrm{\scriptscriptstyle ON}}$ by 32.5% and 36.4% compared with the tridimensional channel (TC) LIGBT and the conventional (Con). LIGBT, respectively. The TGCS LIGBT exhibits high current capability, which has an improvement of 151% and 26.8% compared with those of the Con. LIGBT and the TC LIGBT, respectively. The TGCS LIGBT shows a little better short-circuit capability than does the Con. LIGBT.

In order to find out the appropriate measures for soil water preservation and wheat yield increase, a three–year field experiment was conducted in Yuzhou Experimental Station of Water Saving Agriculture in the west of Henan Province, China, during the growing seasons of 2014–2015, 2015–2016 and 2016–2017 to study the effects of different tillage modes and soil mulching measures on dynamics of soil moisture and temperature, photosynthetic characteristics and yield of winter wheat (Triticum aestivum L.). The results showed that straw coverage and film mulching measures under the conventional tillage and no tillage modes increased soil moisture by 4.4%–27.3%,13.4%–41.8% and 6.2%–46.7%, 2.4%–80.2%, respectively. The treatments of soil surface coverage measures under both conventional tillage and no tillage modes at tillering stage increased the temperature of soil layer at 10 cm and 15 cm depth by 9.1%–18.2% and 10.0%–40.0% in 2014–2015, while mulching measures under the conventional tillage obviously increased soil temperature at wintering stage but decreased soil temperature at booting and mature stages in 2016–2017. However, mulching measures under no tillage mode reduced soil temperature in shallower layer during seedling establishment stage in the three–year period of 2014–2017. Moreover, the two mulching measures raised net photosynthetic rate (Pn) and water use efficiency (WUE) of functional leaves under the conventional tillage mode and reduced transpiration rate (Tr) at the filling stage. Except straw coverage measures under no tillage in 2015–2016, the combination of mulching measures under no tillage reduced Pn, Tr and WUE of wheat leaves at filling stage as compared to those without mulching measures. Under the conventional tillage mode, straw coverage increased wheat yield by 6.4%–9.3%, mainly due to the increase in the number of grains per panicle. Under no tillage mode, both straw coverage and mulching measures reduced wheat yield to different extents and film mulching measures was more effective than straw coverage. The combination of conventional tillage and straw mulching resulted in a yield of 8425.9–8888.9 kg hm−2, so this combination was recommended as the optimal treatment under the conditions set in this study.

Soil amendments, such as straw mulch, organic fertilizers and superabsorbent polymer (SAP), are extensively applied to improve soil structure and porosity, and we reported the functional consequences of the individual application of these amendments in our previous study. However, whether combined amendments are more effective than their individual applications for improving soil pore structure is unknown. Here, we conducted X-ray computed tomography (CT) scanning on undisturbed soil columns to investigate the efficiency of two-amendment application, including straw mulch and organic manure, SAP and organic manure, or SAP and straw mulch, for improving soil pore properties and pore distribution. The X-ray CT technique allows us to accurately determine the number, morphology, and location of macropores (>1 mm in diameter) and smaller pores (0.13–1.0 mm). Compared to the control treatment, which showed the lowest increase in soil porosity, all the combined treatments led to an increase in the numbers of both macropores and smaller soil pores, causing a significant improvement in soil structure and porosity. Among these treatments, the application of both straw mulch and organic manure was the most effective for improving soil porosity and soil physical structure.

Tillage combined with straw mulching is an effective water-saving agricultural strategy in eastern Central China. A two-year field experiment with four treatments, including conventional tillage (CT), conventional tillage with straw mulching (CT+S), no-tillage (NT) and no-tillage with straw mulching (NT+S), was conducted on semihydromorphic soil. The objective was to investigate how tillage with straw mulching affected the soil temperature, water consumption, photosynthetic rate (Pn), grain yield, soil temperature use efficiency (TUE) and water productivity (WP) in a winter wheat-summer maize rotation system. The results indicated that straw mulching tended to increase the soil temperature before the wheat regreening stage and decrease the soil temperature during the following wheat growing season and throughout the maize growing season. Compared with CT, the soil effective accumulated temperature (EAT) under the NT+S treatment significantly decreased by 4.8% but the annual ET increased by 4.3% in the winter wheat–summer maize rotation system. The Pn and transpiration rate (Tr) at the anthesis stage of wheat under the NT+S treatment increased by 15.2% and 15.6%, respectively, and the leaf water use efficiency (LWUE) during the growing season of maize increased by 11.3% as compared with that under CT treatment. Wheat yields decreased in the order of NT+S, NT, CT and CT+S during both experimental years, and the average yield of maize under the NT+S treatment increased by 27.2% compared with that under CT. Additionally, WP values under the NT+S treatment during both the wheat and maize seasons were 7.0% and 21.8% higher than those of the CT treatment (p

An ultra-low specific ON-resistance ( ${R}_{\text {on,sp}}$ ) LDMOS is proposed and investigated by simulation in this letter. It features an extended tri-gate, a trench source, and a trench drain. in the on-state, multi-plane electron accumulation layers (MALs) and hence multiple ultra-low resistance current paths are formed along the bottom surface and side wall of the extended tri-gate. In the OFF-state, the extended gate assists in depleting the drift region and thus increases the doping concentration of the drift region ( ${N}_{d})$ . Both contribute to an ultralow ON-resistance. Moreover, the combined structure of the extended gate and tri-gate enhances the transconductance ( ${g}_{m})$ of the device. Additionally, the trench source and the trench drain shorten the current paths. As a consequence, both the current under the extended tri-gate and the total current increase. The performance of the MAL LDMOS is superior to that of the current state of art. Compared with the 70 V conventional LDMOS (Con. LDMOS) with the same dimension, the MAL LDMOS reduces the ${R}_{\text {on,sp}}$ by 90% and doubles the ${g}_{m}$ owing to the multi-plane accumulation layers. The MAL LDMOS maintains nearly the same breakdown voltage as the Con. LDMOS.

The movement and distribution of the soil water and nitrogen are significantly influenced by tillage management. However, the dynamics of soil water and nitrogen due to changes in tillage and surface residue cover can be difficult to characterize due to limitations in field experimentation. The objective of this study was to quantify the differences in the soil water and nitrogen balance in the 0–100 cm soil profile, winter wheat (Triticum aestivum L.) yield, water productivity (WP) and nitrogen use efficiency (NUE) that occur when conventional tillage (CT) was changed to four types of conservation tillage treatments (no-tillage [NT], subsoiling tillage [ST], no-tillage with straw [NS] and subsoiling tillage with straw [SS]). Experimental data from 2011 to 2016 collected in Henan province, China on a sandy loam soil was used to calibrate and validate the Root Zone Water Quality Model (RZWQM2). Then the model was used to simulate four tillage systems (NT, NS, ST, SS) that were then compared with CT. The agreement index (d) between simulated and measured soil water content, soil nitrate concentration, and grain yield ranged between 0.71 and 0.93. The root means square error (RMSE) of the soil water content and nitrate concentration was in the range 0.02–0.03 cm cm−1and 5.5–10.3 mg kg−1, respectively. When CT was converted to NT from 2011 to 2016, the model simulated a 9.1 % reduction in annual water loss and a 55.6 % decrease in nitrogen leaching loss and simulated significant increase in average grain yield, WP and NUE. Replacing CT with NT appears to be the best of the four alternative conservation tillage conversion strategies in Henan Province of China.

Background Adenocarcinoma, the most common form of lung cancer, is one of main human malignant tumors. In this paper, we focus on the effect of antitumor activity of cytokine-induced killer (CIK) cells on human lung adenocarcinoma cell line A549. Methods CIK cells were obtained by inducing peripheral blood mononuclear cells with recombinant human (rh) interferon-gamma, monoclonal anti-CD3 antibody, rh interleukin (IL)-1alpha, and rhIL-2, which were added into the culture. A549 cell viability of CIK cells was determined using MTS assay. Flow cytometry (FCM) experiments were performed to detect cell cycle changes. The expression of P27 in A549 cells treated by CIK cells was evaluated by Western blot. Result The percentage of CD3+CD16+CD56+ T cells in a representative peripheral blood mononucleated cell sample was 33.7 ± 1.3%. CIK cells, in dose and time dependent manners, inhibited the proliferation of A549. FCM demonstrated that A549 cells were accumulated in G2/M and G0/G1 phases when treated with CIK cells. FCM was used to analyze whether A549 cells treated with CIK cells induced apotosis or necrosis at 10:1 or 20:1. Compared to the control group, P27 was prominently upregulated in the CIK treated group. Conclusion We propose that the pharmacological mechanisms of A549 cells inhibited by CIK cells can be estimated to possibly elicit different biological significance, which, in part, can be ascribed to a different mass transport rate in vitro.

Eutrophication in lakes or reservoirs can lead to blue-green algae(BGA) bloom that is detrimental to the aquatic ecosystems and often pose a potentially serious health threat to people having access to the impaired waters.Since 1990s,Lake Dianchi has been experiencing BGA bloom almost on an annual basis,raising ever increasing levels of concerns from the public and governments.To control the eutrophication and reduce the outbreak frequency of BGA bloom in Lake Dianchi,it is necessary to identify the responsive relationship between the BGA bloom and the influencing factors including nutrient loadings,weather conditions,among others.However,to fulfill this task is very difficult in practice since there exist no,and it is impossible to obtain,a complete dataset that simultaneously covers the occurrence of BGA bloom and the influencing factors due to the transient and heterogeneous nature of the Lake Dianchi system.Even though the remote sensing technology offers a cost-effective way to acquire data about the occurrence of BGA bloom,it still far from sufficient to provide a complete dataset due to the data gap from lack of observations or interruption by clouds. To overcome the data limitation in deriving reliable relationship between BGA blooms and the main influencing factors,this study applied a robust EMB algorithm to reconstruct a complete dataset from the available dataset with missing data,hence forming a basis for quantitatively relating the BGA bloom to its contributing factors.The analysis starts with discovering the general trend of BGA bloom in Lake Dianch through using boxplots of chlorophyll-a data in the lake,which shows that the area represented by monitoring station Huiwanzhong appears to be the most likely place for BGA bloom.As for temporal trend,it was found that the chlorophyll-a concentration doesn′t have as much variability inter-annually as intra-annually.In general,chlorophyll-a concentrations increase from February to August,and then decrease thereafter until the next February.Subsequently,a multiple imputation based EMB algorithm was employed to re-construct the entire basic datasets from month April to October from 2004 through 2008 for the Waihai of Lake Dianchi based on the available incomplete datasets of weather condition and BGA bloom.With the complete datasets,the relationship between chlorophyll-a and outbreak probability of BGA bloom was established using conditional probability curves for two time ranges,i.e.,from April to October and June to September,respectively.The analysis suggests that there is a threshold concentration of chlorophyll-a determining whether a BGA bloom would occur.However,the same method was found to be invalid for analyzing the relationship between outbreak frequency and nutrient concentrations.The scatter plots of TN vs.TP along with labels of BGA bloom occurrence indicate that 1) there might not be a threshold exists for TN or TP to control BGA;2) it seems more efficient to reduce concentration of TN than TP;3) it is necessary to control concentration of TN and TP at a reasonable and realistic range,while pursuing a higher water quality standard in short term might not be necessary. The results of this study suggest that it is critical to reduce TN and TP under water quality standard level V by all means,while at the same time,supplemental measures such as water volume control,water quality and hydrodynamic condition adjustment and aquatic ecosystem restoration should be taken to direct the lake ecological system to evolve from the phytoplankton dominant regime to the macrophyte dominant regime.

With the rapid development of ecology and increased concern on environment and resources, forest management have shifted from single-target (such as timber production, ecological shelter, biodiversity conservation) traditional forest management to multi-target biodiversity-oriented forest management for sustainable ecology, economy and society. Given hierarchical complexities of forest system and multi-target forest management, forestry decision support system (DDS) has emerged as an important tool to determine management objectives, design scenarios, assess climate change and management plan. The core components of forest management DDS are habitat suitability and forest dynamics models used to assess the impact of management scenarios and climate change on forest functions, services and especially biodiversity conservation. In this paper, the development of forest dynamics and habitat suitability models are discussed, followed by a forestry DSS review with a particular focus on the current state and problems.

[ABSTRACT] An attempt was made to assess the effect of increase in mean annual temperature and precipitation on forest growth rate. By analyzing data from 77 meteorological stations and 721 forest sample plots in different faces of Taihang Mountain, it was approved, through regression, that there was a good relationship between temperature and forest growing stock in the whole Taihang Mountain. And furthermore, the effect of temperature on forest growing stock in different faces represented by Shanxi Province in the northwest slope of the whole Taihang Mountain, which run from southwest to northeast, and Hebei Province in the southeast face was analyzed. The result suggested that, in Shanxi Province, 1℃ of temperature increase could result in 3.8m^3 decrease in forest growing stock. But in Hebei Province, 1℃ of temperature increase could result in 6.88 to 8.68 m^3/ha of decrease in forest growing stock for 23 year's old forest averagely. The relationship between precipitation and forest growing stock was not very certain since the unevenly distribution of rainfall in this region.

Time-selective channel estimator for orthogonal frequency division multiplexing (OFDM) systems using pilot added scheme is proposed in this paper. The OFDM system is with robustness to multipath fading in wireless communications. At the same time, time-variation can destroy the orthogonality between subcarriers which will degrade the performance of the system. In this paper, we propose a pilot added scheme which superimposes periodic pilot sequences on information bearing symbols. This approach is computationally simple and spectrally efficient as well. The results of computer simulations are presented and the factors which can affect the performance are analyzed.

In this paper, the high-voltage, ultra-shallow junction PJFET was fabricated with the Bi-FET (JFET compatible bipolar) process. The device with the top-gate junction depth about 0.1µm, the breakdown voltage more than 80V, the gate-leakage current less than 5 pA, and the pinch-off voltage 0.8V~2.0V adjustable was realized. The PJFET and its Bi-FET process technology were used to design and process a high-precision integrated OPA. The measured results showed that the OPA has the bias current of less than 50 pA, the voltage noise of less than 50 nV/Hz1/2, and the current noise of less than 0.05 pA/Hz1/2.

In this paper, an authentication mechanism based on key refurbish is proposed to solve the problems of secret key distribution and management, and a new scheme is designed to realize mutual authentication and generate a session key confirmed by both sides of communication. This scheme has the advantages of simple structure and high efficiency, which also provides a non-repudiation service.

In this paper, we present a space time block coded (STBC) MIMO-OFDM scheme for indoor UWB using whose channel is frequency selective because of full of multipaths. After briefly introducing transmit diversity of MIMO-OFDM, we give out STBC scheme which can achieve space and frequency diversity gain. Numerical simulation results show that in the UWB environment, the performance of the STBC MIMO-OFDM system proposed in this paper is improved compared with conventional space frequency block coded OFDM systems.

Doubly-selective channel estimator for orthogonal frequency division multiplexing (OFDM) systems is proposed in this paper. Based on the generalized complex exponential basis expansion model (GCE-BEM), we describe the time-variant channel with time-invariant coefficients over multiple OFDM blocks. The time variation of channel destroys the orthogonality between subcarriers. The resulting channel matrix in the frequency domain is no longer diagonal, but the main interference comes from the near subcarriers. Based on this, we propose a least-square (LS) channel estimator with low pilot ratio. The proposed estimator is with the advantages of low pilot ratio and robustness against inter-carrier interference.

Two types of 5 μm thick hybrid orientation structure wafers, which were integrated by (110) or (100) orientation silicon wafers as the substrate, have been investigated for 15–40 V voltage ICs and MEMS sensor applications. They have been obtained mainly by SOI wafer bonding and a non-selective epitaxy technique, and have been presented in China for the first time. The thickness of BOX SiO2 buried in wafer is 220 nm. It has been found that the quality of hybrid orientation structure with (100) wafer substrate is better than that with (110) wafer substrate by "Sirtl defect etching of HOSW".

A novel structure of a VDMOS in reducing on-resistance is proposed. With this structure, the specific on-resistance value of the VDMOS is reduced by 22% of that of the traditional VDMOS structure as the breakdown voltage maintained the same value in theory, and there is only one additional mask in processing the new structure VDMOS, which is easily fabricated. With the TCAD tool, one 200 V N-channel VDMOS with the new structure is analyzed, and simulated results show that a specific on-resistance value will reduce by 23%, and the value by 33% will be realized when the device is fabricated in three epitaxies and four buried layers. The novel structure can be widely used in the strip-gate VDMOS area.

A novel depletion-mode NJFET compatible high-voltage BiCMOS process is proposed and experimentally demonstrated with a four-branch 12-bit DAC (digital-to-analog converter). With this process, an NJFET with a pinch-off voltage of about-1.5 V and a breakdown voltage of about 16 V, an NLDDMOS (N-type lightly-dosed-drain in MOS) with a turn-on voltage of about 1.0 V and a breakdown voltage of about 35 V, and a Zener diode with a reverse voltage of about 5.6 V were obtained. Measurement results showed that the converter had a reference temperature coefficient of less than ±25 ppm/°C, a differential coefficient error of less than ±0.3 LSB, and a linear error of less than ±0.5 LSB. The depletion-mode NJFET and its compatible process can also be widely used for high-voltage ADCs or DACs.

The characteristics of radiation damage under a high or low dose rate in lateral PNP transistors with a heavily or lightly doped emitter is investigated. Experimental results show that as the total dose increases, the base current of transistors would increase and the current gain decreases. Furthermore, more degradation has been found in lightly-doped PNP transistors, and an abnormal effect is observed in heavily doped transistors. The role of radiation defects, especially the double effects of oxide trapped charge, is discussed in heavily or lightly doped transistors. Finally, through comparison between the high- and low-dose-rate response of the collector current in heavily doped lateral PNP transistors, the abnormal effect can be attributed to the annealing of the oxide trapped charge. The response of the collector current, in heavily doped PNP transistors under high- and low-dose-rate irradiation is described in detail.

With Shockley's approximate-channel theory and TCAD tools, a high-voltage, ultra-shallow junction PJFET for the input stage of an integrated operational amplifier (OPA) was realized. The high-performance PJFET device was developed in the Bi-FET process technology. The measured specifications are as follows. The top-gate junction depth is about 0.1 μm, the gate-leakage current is less than 5 pA, the breakdown voltage is more than 80 V, and the pinch-off voltage is optional between 0.8 and 2.0 V. The device and its Bi-FET process technology were used to design and process a high input-impedance integrated OPA. The measured results show that the OPA has a bias current of less than 50 pA, voltage noise of less than 50 nVTHz1/2, and current noise of less than 0.05 pA/Hz1/2.

Several novel prokaryotic and eukaryotic expression vectors were constructed for protein transduction and subcellular localization. These vectors employed an N-terminal stretch of 11 basic amino acid residues (47–57) from the human immunodeficiency virus type 1 (HIV-1) TAT protein transduction domain (PTD) for protein translocation and cellular localization. The vectors also contained a six-histidine (His6) tag at the N- or C-terminus for convenient purification and detection, and a multiple cloning site for easy insertion of foreign genes. Some heterologous genes including HSV-TK, Bcl-rambo, Smac/DIABLO and GFP were fused in-frame to TAT PTD and successfully overexpressed in Escherichia coli. The purified TAT-GFP fusion protein was able to transduce into the mammalian cells and was found to locate mainly in the cytosol when exogenously added to the cell culture medium. However, using a transfection system, mammalian-expressed TAT-GFP predominantly displayed a nuclear localization and nucleolar accumulation in mammalian cell lines. This discrepancy implies that the exact subcellular localization of transduced protein may depend on cell type, the nature of imported proteins and delivery approach. Taken together, our results demonstrate that a TAT PTD length of 11 amino acids was sufficient to confer protein internalization and its subsequent cellular localization. These novel properties allow these vectors to be useful for studying protein transduction and nuclear import.