A comprehensive review on the preparation and application of calcium hydroxyapatite: A special focus on atomic doping methods for bone tissue engineering

Hydroxyapatite (HAP) has been considered to be one of the most preferred scaffold materials among many in the last decade for the bone tissue engineering. Be it prosthetic implants, scaffolds or artificial bone cement, hydroxyapatite has received highest attraction among all due to its chemical and physical properties similar to that of human bone. Although it can be used in the bone tissue engineering as the original composition; for enhancing its different properties relevant to in vivo applications, the calcium in HAP may also be replaced by other atomic dopants depending on usage. Here, we review various HAP coating agents and methods, their merits and demerits. We also review various HAP doping materials, including both cationic as well as anionic materials. We discuss the effects and usage of substitution of hydroxyapatite and their subsequent usage in both bone tissue engineering and maxillofacial surgeries. We consider various research articles published in recent times to accomplish detailed discussion on the subject.     

Efficient overall water splitting over a Mo(IV)-doped Co3O4/NC electrocatalyst

To meet the demand of producing hydrogen at low cost, a molybdenum (Mo)-doped cobalt oxide (Co₃O₄) supported on nitrogen (N)-doped carbon (x%Mo–Co₃O₄/NC, where x% represents Mo/Co molar ratio) is developed as an efficient bifunctional electrocatalyst for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). This defect engineering strategy is realized by a facile urea oxidation method in nitrogen atmosphere. Through X-ray diffraction (XRD) refinement and other detailed characterizations, molybdenum ion (Mo⁴⁺) is found to be doped into Co₃O₄ by substituting cobalt ion (Co²⁺) at tetrahedron site, while N is doped into carbon matrix simultaneously. 4%Mo–Co₃O₄/NC is the optimized sample to show the lowest overpotentials of 91 and 276 mV to deliver 10 mA cm^?2 for HER and OER in 1 M potassium hydroxide solution (KOH), respectively. The overall water splitting cell 4%Mo–Co₃O₄/NC||4%Mo–Co₃O₄/NC displays a voltage of 1.62 V to deliver 10 mA cm^?2 in 1 M KOH. The Mo⁴⁺ dopant modulates the electronic structure of active cobalt ion (Co³⁺) and boosts the water dissociation process during HER, while the increased amount of lattice oxygen and formation of pyridinic nitrogen due to Mo doping benefits the OER activity. Besides, the smaller grain size owing to Mo doping leads to higher electrochemically active surface area (ECSA) on 4%Mo–Co₃O₄/NC, resulting in its superior bifunctional catalytic activity.     

非建设属性类国有企业开展全过程工程咨询的实施策略研究

分析非建设属性类国有企业开展基建项目时存在的优势和劣势,提出非建设属性类国有企业采用全过程工程咨询的实施策略,包括实施模式,委托阶段、委托方式、项目后评价四个方面。以某烟草企业经营业务用房建设项目为例,分析非建设属性类国有企业采用传统建设模式开展基建项目存在的问题和采用全过程工程咨询模式的优势,为非建设属性类国有企业采用全过程工程咨询提供参考借鉴。     

An Innovative Non-Pillar Coal-Mining Technology with Automatically Formed Entry: A Case Study

A non-pillar coal-mining technology with an automatically formed entry is proposed, which reduces the waste of coal resources and the underground entry drivage workload. Three key techniques in this technology cooperate to achieve automatic formation and retaining of the gob-side entry, and to realize non-pillar mining. Constant-resistance large deformation (CRLD) support ensures the stability of the entry roof; directional presplitting blasting (DPB) separates the entry roof and the gob roof; and a blocking-gangue support system (BGSS) integrates the caved rock material as an effective entry rib. An industrial test was conducted to verify the engineering effects of these key techniques. The field application results showed that the retained entry was under the pressure-relief zone due to the broken-expansion nature of the caved rock mass within the DPB height. After going through a provisional dynamic pressure-bearing zone, the retained entry entered the stability zone. The final stable entry meets the requirements of safety and production. The research results demonstrate the good engineering applicability of this technology. By taking the framework of the technology design principles into consideration and adjusting the measures according to different site conditions, it is expected that the proposed non-pillar coal-mining technology can be popularized on a large scale.     

基于熵权TOPSIS的工程咨询机构BIM技术应用能力评价

构建工程咨询机构BIM技术应用能力评价的指标体系,提出改进的熵权TOPSIS评价模型,以4个典型的工程咨询单位为例,进行BIM技术运用能力评价。研究表明,BIM行业的整体水平已经有了明显的提升,但是区域间的发展还存在一定差距。     

抗凝冰乳化沥青涂层的性能研究

为了研究自制融雪剂对抗凝冰乳化沥青涂层性能的影响,将自制固态型融雪剂按5%、10%、15%的比例加入乳化沥青制备涂层乳液,采用水煮法、摆式摩擦仪、电导率试验分别对涂层材料的粘附性、抗滑性能和抗凝冰性能进行了测试。结果表明:自制型融雪剂对乳化沥青与集料的粘附性影响不大;随着融雪剂掺配比例的增大,抗凝冰乳化沥青涂层的摩擦系数有所降低,但均满足规范要求;相比于普通沥青涂层,抗凝冰乳化沥青涂层的抗凝冰性能得到改善,且随着融雪剂掺配比例的增大,凝冰性能逐渐提高。     

Blockchain-oriented dynamic modelling of smart contract design and execution in the supply chain

Recently, the applications of Blockchain technology have begun to revolutionise different aspects of supply chain (SC) management. Among others, Blockchain is a platform to execute the smart contracts in the SC as transactions. We develop and test a new model for smart contract design in the SC with multiple logistics service providers and show that this problem can be presented as a multi-processor flexible flow shop scheduling. A distinctive feature of our approach is that the execution of physical operations is modelled inside the start and completion of cyber information services. We name this modelling concept ‘virtual operation’. The constructed model and the developed experimental environment constitute an event-driven dynamic approach to task and service composition when designing the smart contract. Our approach is also of value when considering the contract execution stage. The use of state control variables in our model allows for operations status updates in the Blockchain that in turn, feeds automated information feedbacks, disruption detection and control of contract execution. The latter launches the re-scheduling procedure, comprehensively combining planning and adaptation decisions within a unified methodological framework of dynamic control theory. The modelling complex developed can be used to design and control smart contracts in the SC.