Influence of Diesel Engine Intake Throttle and Late Post Injection Process on the Rise of Temperature in the Diesel Oxidation Catalyst

In order to effectively implement DPF(Diesel Particulate Filters)regeneration control,thermal management of exhaust products before and inside Diesel Oxidation Catalyst(DOC)is necessary.In the present study,the Influence of the intake throttle valve and late post injection process on temperature rise inside DOC is analyzed through engine bench tests.The steady experiment results show that adjustment of the intake throttle valve can effectively increase exhaust temperature before DOC;in particular,with intake throttle valve opening at 20%,temperature before DOC can be increased by about 170℃ with respect to the full opening.An increase in the late post injection quantity can produce a significant rise of the temperature inside DOC,however its impact on the exhaust temperature before DOC is relatively limited.As the late post injection quantity increases,Hydrocarbon(HC)emissions also grow;in the present work it is shown that with a proper injection quantity,a considerable temperature increase inside the DOC can be obtained with relatively low HC emission.More specifically,with the intake throttle valve at 30%and DOC reaching ignition temperature as the late post injection quantity is increased,the exhaust temperature after DOC can be made larger than 550℃,adequate for DPF active regeneration.

CFD Analysis and Optimization of a Diesel Engine Cooling Water Jacket

The STAR-CCM+software is used to investigate the flow inside a cooling water jacket of an in-line six-cylinder diesel engine.The results show that the average flow velocity of the cooling water inside the jacket is 1.669 m/s while the flow velocity distribution is not uniform for each cylinder.Moreover,the fluid velocity in proximity to the cylinder head is too low,thereby affecting the cooling performances of the water jacket.Two corresponding structural optimization schemes are proposed to mitigate this issue and the post-optimization performances of the water jacket are discussed in detail.

Impact of effective stress on permeability for carbonate fractured-vuggy rocks

To gain insight into the flow mechanisms and stress sensitivity for fractured-vuggy reservoirs,several core models with different structural characteristics were designed and fabricated to investigate the impact of effective stress on permeability for carbonate fractured-vuggy rocks(CFVR).It shows that the permeability performance curves under different pore and confining pressures(i.e.altered stress conditions)for the fractured core models and the vuggy core models have similar change patterns.The ranges of permeability variation are significantly wider at high pore pressures,indicating that permeability reduction is the most significant during the early stage of development for fractured-vuggy reservoirs.Since each obtained effective stress coefficient for permeability(ESCP)varies with the changes in confining pressure and pore pressure,the effective stresses for permeability of four representative CFVR show obvious nonlinear characteristics,and the variation ranges of ESCP are all between 0 and 1.Meanwhile,a comprehensive ESCP mathematical model considering triple media,including matrix pores,fractures,and dissolved vugs,was proposed.It is proved theoretically that the ESCP of CFVR generally varies between 0 and 1.Additionally,the regression results showed that the power model ranked highest among the four empirical models mainly applied in stress sensitivity characterization,followed by the logarithmic model,exponential model,and binomial model.The concept of“permeability decline rate”was introduced to better evaluate the stress sensitivity performance for CFVR,in which the one-fracture rock is the strongest,followed by the fracture-vug rock and two-horizontalfracture rock;the through-hole rock is the weakest.In general,this study provides a theoretical basis to guide the design of development and adjustment programs for carbonate fractured-vuggy reservoirs.

Experimental Study on Gas Flow Uniformity in a Diesel Particulate Filter Carrier

A Diesel Particulate Filter(DPF)is a critical device for diesel engine exhaust products treatment.When using active-regeneration purification methods,on the one hand,a spatially irregular gas flow can produce relatively high local temperatures,potentially resulting in damage to the carrier;On the other hand,the internal temperature field can also undergo significant changes contributing to increase this risk.This study explores the gas flow uniformity in a DPF carrier and the related temperature behavior under drop-to-idle(DTI)condition by means of bench tests.It is shown that the considered silicon carbide carrier exhibits good flow uniformity,with a temperature deviation of no more than 2%with respect to the same radius measurement point at the outlet during the regeneration stage.In the DTI test,the temperature is relatively high within r/2 near the outlet end,where the maximum temperature peak occurs,and the maximum radial temperature gradient is located between r/2 and the edge.Both these quantities grow as the soot load increases,thereby making the risk of carrier burnout greater.Finally,it is shown that the soot load limit of the silicon carbide DPF can be extended to 11 g/L,which reduces the frequency of active regeneration by approximately 40%compared to a cordierite DPF.

Ecological Networks of Allometric Growth,Feeding Behavior and Gut Microbiota in Chinese Alligator Hatchlings

Chinese alligator hatchlings in captivity are fragile and have a high mortality rate within first year.The body mass gain of reptile animals is closely related to their feeding behavior and gut microbiota.This study analyzed the intrinsic factors influencing the allometric growth of Chinese alligator hatchlings based on their body mass gain,feeding behavior,and gut microbiota.This information would enhance the health management of Chinese alligator hatchlings.There was a significant correlation between the total distance moved,the average number of conspecifics nearby,and body mass gain.Chinese alligator hatchlings with a greater growth rate showed greater activity and more independent behavior during feeding than those with a lower growth rate.Moreover,after feeding started,some functions of the gut microbiota showed significant relationships with growth rate and feeding activity.Chinese alligator hatchlings with a greater growth rate showed greater levels of heme biosynthesis than those with a lower growth rate,and feeding activity was inhibited by long-chain fatty acid biosynthesis.These results elucidate the relationships between health,feeding behavior,and the gut microbiota of Chinese alligator hatchlings.Understanding the intrinsic factors of their health and feeding behavior can improve the health management of Chinese alligator hatchlings in captivity for conservation.

WT-FCTGN:A wavelet-enhanced fully connected time-gated neural network for complex noisy traffic flow modeling

Accurate forecasting of traffic flow provides a powerful traffic decision-making basis for an intelligent transportation system. However, the traffic data's complexity and fluctuation, as well as the noise produced during collecting information and summarizing original data of traffic flow, cause large errors in the traffic flow forecasting results. This article suggests a solution to the above mentioned issues and proposes a fully connected time-gated neural network based on wavelet reconstruction(WT-FCTGN). To eliminate the potential noise and strengthen the potential traffic trend in the data, we adopt the methods of wavelet reconstruction and periodic data introduction to preprocess the data. The model introduces fully connected time-series blocks to model all the information including time sequence information and fluctuation information in the flow of traffic, and establishes the time gate block to comprehend the periodic characteristics of the flow of traffic and predict its flow. The performance of the WT-FCTGN model is validated on the public Pe MS data set. The experimental results show that the WT-FCTGN model has higher accuracy, and its mean absolute error(MAE), mean absolute percentage error(MAPE) and root mean square error(RMSE) are obviously lower than those of the other algorithms. The robust experimental results prove that the WT-FCTGN model has good anti-noise ability.

Analysis of the Influence of Geometrical Parameters on the Performance of a Proton Exchange Membrane Fuel Cell

A suitable channel structure can lead to efficient gas distribution and significantly improve the power density of fuel cells.In this study,the influence of two channel design parameters is investigated,namely,the ratio of the channel width to the bipolar plate ridge width(i.e.,the channel ridge ratio)and the channel depth.The impact of these parameters is evaluated with respect to the flow pattern,the gas composition distribution,the temperature field and the fuel cell output capability.The results show that a decrease in the channel ridge ratio and an increase in the channel depth can effectively make the distributions of velocity,temperature and concentration more uniform in each channel and improve the output capability of the fuel cell.An increase in the channel ridge ratio and depth obviously reduces the flow resistance and improves the flow characteristics.

An organic visible-photocatalytic-adsorbence mechanism to high-efficient removal of heavy metal antimony ions

Purification of emerging heavy metal antimony contaminated water based on advanced ingenious strategies.An activated modified coconut shell charcoal(CSC)was synthesized and evaluated as a substrate-supported loaded organic photovoltaic material,PM6:PYIT:PM6-b-PYIT,to prepare a surprisingly highly efficient,stable,environmentally friendly,and recyclable organic photocatalyst(CSC–N–P.P.P),which showed excellent effects on the simultaneous removal of Sb(Ⅲ)and Sb(Ⅴ).The removal efficiency of CSC-N-P.P.P on Sb(Ⅲ)and Sb(Ⅴ)reached an amazing 99.9%in quite a short duration of 15 min.At the same time,under ppb level and indoor visible light(~1 W m^(2)),it can be treated to meet the drinking water standards set by the European Union and the U.S.National Environmental Protection Agency in 5 min,and even after 25 cycles of recycling,the efficiency is still maintained at about 80%,in addition to the removal of As(Ⅲ),Cd(Ⅱ),Cr(Ⅵ),and Pb(Ⅱ)can also be realized.The catalyst not only solves the problems of low reuse rate,difficult structure adjustment and high energy consumption of traditional photocatalysts but also has strong applicability and practical significance.The pioneering approach provides a much-needed solution strategy for removing highly toxic heavy metal antimony pollution from the environment.

Research on ECMS Based on Segmented Path Braking Energy Recovery in a Fuel Cell Vehicle

Proton exchange membrane fuel cells are widely regarded as having the potential to replace internal combustion engines in vehicles.Since fuel cells cannot recover energy and have a slow dynamic response,they need to be used with different power sources.Developing efficient energy management strategies to achieve excellent fuel economy is the goal of research.This paper proposes an adaptive equivalent fuel minimum consumption strategy(AECMS)to solve the problem of the poor economy of the whole vehicle caused by the wrong selection of equivalent factors(EF)in traditional ECMS.In this method,the kinematics interval is used to update the equivalent factor by considering the penalty term of energy recovery on SOC changes.Finally,the optimized equivalent factor is substituted into the optimization objective function to achieve efficient energy regulation.Simulation results under the New European Driving Cycle show that compared with the traditional ECMS based on fixed SOC benchmarks,the proposed method improves fuel economy by 1.7%while ensuring vehicle power and increases SOC by 30%.

Antioxidant Activity of Ethyl Acetate Extract of Amomum villosum Lour.

[Objectives]To study the antioxidant activity of the ethyl acetate extract of Amomum villosum Lour.[Methods]The removal rate of chelated iron ions,hydroxyl radicals,superoxide anion free radicals and DPPH free radicals by the ethyl acetate extract of A.villosum Lour.was determined by UV spectrophotometer.[Results]0.5000μg/mL ethyl acetate extract of A.villosum Lour.had the strongest ability to chelate with ferrous ions and to remove hydroxyl radicals,superoxide anion free radicals and DPPH free radicals.The ability to chelate with ferrous ions was 95.14%,and the removal rate of the above free radicals was 86.217%,81.44%,and 85.16%.[Conclusions]The ethyl acetate extract of A.villosum Lour.had a strong antioxidant effect,and its antioxidant capacity was related to the sample concentration,which provides a theoretical basis for its application in the development of antioxidant skin care products.

Study of the Effects of Lower Limb Muscle Strengthening Exercises on Hospitalized Pregnant Women on Bed Rest for Prevention of Miscarriage

Objective: Against a background of the two-child policy in China, the objective is to explore the effects of lower limb strengthening exercises on hospitalized pregnant women put on bed rest for prevention of miscarriage. Method: Sixty cases of pregnant women admitted to the Department of Obstetrics in one of the highest ranking hospitals in Guangzhou, China, during the period from November 2018 to December 2019 for the purpose of preventing miscarriage were selected. They were divided into an experimental group and a control group of 30 cases each. The control group was put under routine care while the intervention group conducted lower limb muscle strengthening exercise on top of the routine care. After the intervention, the conditions of lower limbs, the psychological states and the results of pregnancy for the two groups were compared. Results: After the intervention, the scores of the experimental group in anxiety, depression and postpartum depression were lower and leg circumferences were smaller compared to the control group. The difference is statistically significant (P < 0.05). The experimental group had longer gestation than the control group and was able to get out of bed earlier than the control group after delivery, with statistically significant difference (P < 0.05). Conclusion: Lower limb muscle strengthening exercises can effectively improve the physiological and psychological states of pregnant women hospitalized for prevention of miscarriage and promote their postpartum recovery.

钙钛矿型水氧化电催化剂

在全球能源结构“清洁化”转型的背景下,可再生能源的开发与利用能够有效解决能源危机与环境问题,符合我国的可持续发展路线。能源转换与储存技术贯穿着循环能源技术的各个环节,是新型能源框架的核心支撑。水氧化反应是众多能源体系(例如,水裂解反应、二氧化碳还原反应、氮还原反应和金属-空气电池)的重要半反应,但其动力学缓慢,严重限制了设备的能源效率,阻碍了相应技术的广泛应用。因此,亟需开发具有低成本、高活性、强稳定性的水氧化电催化剂以降低反应能垒,进而推动能源转换与存储设备的工业化发展。钙钛矿型材料的晶体结构包容性强,元素组成涵盖广泛,具有丰富而独特的电子特性,易于实现表面化学与电子结构的精准调控,因此被公认为理想的催化材料设计平台。本文综述了钙钛矿型水氧化电催化剂的最新研究进展。首先介绍了钙钛矿型材料的晶体结构和电子特性,归纳了制备钙钛矿型氧化物的代表性的合成策略。通过讨论近期钙钛矿型水氧化电催化剂在酸性和碱性介质中的研究进展,强调了钙钛矿型电催化剂结构与催化性能间的构效关系。最后,我们总结了钙钛矿型水氧化电催化剂在实际应用中面临的挑战与机遇,提出了相应的建议与解决方案,期望能使读者更清晰地认识到该领域的未来发展方向。

有机配体表面改性NiCo2O4纳米线用于水全分解

由于水分解在绿色能源领域的重要作用,能够在碱性介质中进行析氢(HER)和析氧(OER)反应的双功能电催化剂具有重要的应用价值。本文报道一种具有丰富缺陷的表面改性NiCo_(2)O_(4)纳米线(NWs),在碱性介质中作为一种高效的整体水裂解电催化剂。X射线光电子能谱(XPS)分析表明,Co^(2+)/Co^(3+)比值的增加是表面修饰NiCo_(2)O_(4)纳米线具有优异双功能电催化性能的重要原因。结果表明,在1.0 mol·L^(−1)KOH溶液中,通过有机配体主导的表面改性,优化后的NiCo_(2)O_(4)纳米线在电流密度达到10 mA·cm^(−2)时的HER过电位仅为83 mV,OER过电位仅为280 mV。更重要的是,有机配体表面改性后的NiCo_(2)O_(4)纳米线表现出了出色的水分解性能,在2.1 V电压下达到了100 mA·cm^(−2)的电流密度。目前的工作凸显了提高NiCo_(2)O_(4)NWs尖晶石结构中Co^(2+)含量对促进整体水裂解的重要性。

胃癌及胃高级别上皮内瘤变多灶现象的临床研究

目的:探讨同时性多发性胃癌和(或)高级别上皮内瘤变的临床病理特点,分析病灶之间的关联性。方法:收集2007年11月至2017年12月间于石河子大学医学院第一附属医院接受内镜下黏膜剥脱术或外科手术的56例同时性多发性胃癌和(或)高级别上皮内瘤变患者的临床资料,分析其临床病理特点,根据多发性胃癌中对主、副病灶的定义,探究病灶间的关联性。结果:56例同时性多发性胃癌和(或)高级别上皮内瘤变患者平均年龄为(63.82±11.88)岁,男性多见,占75%(42/56),伴有病灶周围黏膜萎缩患者为25例(44.64%)。主、副病灶的浸润深度均以T1期为主。主、副病灶的直径呈正相关(r=0.797,P<0.001),病理类型具有关联性(P=0.007);内镜分型具有较高的一致性(P<0.001);在空间分布方面,主、副病灶也具有关联性,其中垂直位置列联相关系数c=0.484(P=0.002),水平位置列联相关系数c=0.535(P=0.007)。同时性多发性胃癌和(或)高级别上皮瘤变中主病灶在淋巴结转移、TNM分期、是否合并黏膜萎缩等方面与单发性胃癌或高级别上皮内瘤变存在差异。结论:同时性多发性胃癌和(或)高级别上皮内瘤变的高危人群为合并黏膜萎缩的老年男性,在胃镜检查时应注意根据主、副病灶间的关联性仔细观察,避免漏诊。

Central pancreatectomy for pancreatic schwannoma: A case report and literature review

Schwannomas are mesenchymal tumors originating from Schwann cells in peripheral nerve sheaths. Although the tumor can be located in any part of the human body, the most common locations are the head, neck, trunk and extremities. Pancreaticschwannomas are rare. To our knowledge, only 64 cases of pancreatic schwannoma have been reported in the English literature over the past 40 years. In this paper, we present a pancreatic schwannoma in a 59-year-old female. Ultrasound, computed tomography and magnetic resonance imaging revealed the tumor located in the pancreatic body; however, accurate diagnosis was hard to obtain preoperatively and a pancreatic cystadenoma was preliminarily considered. During laparotomy, the mass was found in the body of the pancreas. An enlarged gallbladder with multiple stones was also observed. We performed central pancreatectomy, end-to-side pancreaticojejunostomy and cholecystectomy. Notably, central pancreatectomy has been reported in only one case prior to this report. The gross specimen showed a mass with a thin capsule, 1.6 cm × 1.1 cm × 1.1 cm in size. Microscopic examination showed that the tumor was mainly composed of spindle-shaped cells with palisading arrangement and no atypia, which is consistent with a benign tumor. Both hypercellular and hypocellular areas were visible. Immunohistochemical staining revealed strongly positive results for protein S-100. Finally, the tumor was diagnosed as a schwannoma of the pancreatic body. Postoperatively, the patient recovered well and left the hospital 6 d later. During the 53-mo follow-up period, the patient remained well and free of complications.

Identification of Dynamic Active Sites Among Cu Species Derived from MOFs@CuPc for Electrocatalytic Nitrate Reduction Reaction to Ammonia

Direct electrochemical nitrate reduction reaction(NITRR)is a promising strategy to alleviate the unbalanced nitrogen cycle while achieving the electrosynthesis of ammonia.However,the restructuration of the high-activity Cu-based electrocatalysts in the NITRR process has hindered the identification of dynamical active sites and in-depth investigation of the catalytic mechanism.Herein,Cu species(single-atom,clusters,and nanoparticles)with tunable loading supported on N-doped TiO_(2)/C are successfully manufactured with MOFs@CuPc precursors via the pre-anchor and post-pyrolysis strategy.Restructuration behavior among Cu species is co-dependent on the Cu loading and reaction potential,as evidenced by the advanced operando X-ray absorption spectroscopy,and there exists an incompletely reversible transformation of the restructured structure to the initial state.Notably,restructured CuN_(4)&Cu_(4) deliver the high NH_(3) yield of 88.2 mmol h^(−1)g_(cata)^(−1) and FE(~94.3%)at−0.75 V,resulting from the optimal adsorption of NO_(3)^(−) as well as the rapid conversion of^(*)NH_(2)OH to^(*)NH_(2) intermediates originated from the modulation of charge distribution and d-band center for Cu site.This work not only uncovers CuN_(4)&Cu_(4) have the promising NITRR but also identifies the dynamic Cu species active sites that play a critical role in the efficient electrocatalytic reduction in nitrate to ammonia.

色氨酸代谢在炎症性肠病中的研究进展

炎症性肠病(inflammatory bowel disease,IBD)包括溃疡性结肠炎和克罗恩病,其发病机制与肠道菌群紊乱密切相关.肠道菌群紊乱导致的肠道微环境异常影响氨基酸的代谢.色氨酸作为人体必需氨基酸,其代谢产物参与调节免疫、神经元功能和肠道稳态等.IBD疾病的发生与发展伴随色氨酸的缺乏或代谢异常.本综述主要介绍了肠道菌群代谢物色氨酸及其代谢产物与IBD疾病发生与发展之间的关系,并为未来预测IBD疾病活动的诊断方法和治疗IBD的方案提供了新思路.

China Internet Industry State Analysis and Prosperity Indexes

With the background of China's fast growing economy, Internet has become a key factor to keep the economy go steadily. It is important to quantitatively analyze the whole Internet industry and hence master its development direction clearly, which will provide regulators with reference for industry analysis, policy formulation, and policy evaluation. This article re-constructs the calculation method of traditional Prosperity Indexes, and builds up a new indicators portfolio for Internet Industry Prosperity Indexes. By calculation, the Internet Industry Coincidence Index value is 105.9. And the Leading Index and Coincidence Index are all within the up-going range, which suggests that China's Internet Industry is likely to remain in its usual fast growing state.

Successful treatment of a pancreatic schwannoma by spleen-preserving distal pancreatectomy

Schwannomas are neurogenic tumors that arise from the neural sheaths of peripheral nerves. These tumors can be located in any area of the human body; the most common locations are the head, neck, trunk and extremities. Pancreatic schwannomas are very rare. Over the past 40 years, only 67 cases of pancreatic schwannomas have been reported in the English literature. Here we present a case of pancreatic schwannoma in a 62-year-old male. The tumor was revealed by ultrasound and computed tomography in the neck and body of the pancreas. An accurate diagnosis was difficult to obtain preoperatively. The patient consented to the performance of a laparotomy, and the mass was found in the neck and body of the pancreas and successfully treated using a spleen-preserving distal pancreatectomy with splenic artery and vein preservation. The procedure has only been reported in one other case of pancreatic schwannoma; here we present the second reported case. Macroscopically, the tumor was well circumscribed, gray-white in color and 3.3 cm x 2.8 cm in size. Microscopically, the tumor cells were spindle-shaped and had a palisading arrangement with no atypia, which are results compatible with a benign tumor. Both hypercellular and hypocellular areas were visible. Immunohistochemically, the tumor cells were strongly positive for S-100 protein. The tumor was definitively diagnosed as a schwannoma of the pancreatic neck and body. The patient was followed for 72 mo and has been doing well without any complications.

Schwannoma in the hepatoduodenal ligament: A case report and literature review

Schwannomas are mesenchymal neoplasms with low malignant potential that arise from Schwann cells. They can occur almost anywhere, although the most common locations are the head, neck and extremities. Primary benign schwannoma of the hepatoduodenal ligament is rare. To date, only three cases have been reported in the English literature. In the present study, we report a case of hepatoduodenal ligament schwannoma in a 43-year-old male, who was admitted to our hospital because of a abdominal mass found by physical examination. It was hard to determine the definitive location and diagnosis of the mass using ultrasound, computed tomography and magnetic resonance cholangiopancreatography. During laparotomy, the mass was found in the hepatoduodenal ligament and close to the cholecystic duct, so we resected the gallbladder and cholecystic duct along with the mass. The gross specimen revealed an 8.5 cm × 5.5 cm × 3.0 cm localized tumor. Microscopic examination showed that the tumor was mainly composed of spindle-shaped cells. Immunohistochemical staining showed a strong positive S-100 protein reaction. Finally, the lesion was diagnosed as a benign schwannoma in the hepatoduodenal ligament. However, one month later, the patient was readmitted to our hospital because of skin and sclera jaundice caused by common bile duct stenosis without common bile duct stone or tumor. The patient recovered well after implantation of a common bile duct stent under endoscopic retrograde cholangiopancreatography. He was followed up for a period of 17 mo, during which he was well with no complications.